What is Laser Direct Imaging (LDI)? Role in PCB Fabrication

Hey readers! Hopefully, you are having a great day. Today, we will discuss Laser Direct Imaging (LDI) and its role in PCB fabrication. Laser Direct Imaging (LDI) is a computer-directed method that employs laser beams to expose circuit patterns directly onto photoresist-coated PCBs, without the need for conventional photomasks.

Printed Circuit Boards are the unobtrusive facilitators of contemporary technology, energizing anything from consumer products to aerospace technologies. As the pace of technology advances, however, the electronics within must make their circuits tighter, more advanced, and more efficient. Complying with these demands depends on innovation along every production process, particularly with how circuitry patterns are replicated onto the board.

This important step, imaging, formerly used photomasks and ultraviolet light to pattern-expose a photosensitive surface. Effective enough for ordinary layouts, the technique has trouble keeping pace with the growing requirement for fine-line resolution and variable production.

Laser Direct Imaging, or LDI, provides a compelling solution. Rather than employing physical masks, LDI employs digitally guided laser beams to directly expose the circuit pattern onto the photoresist layer. This maskless process allows for higher accuracy, accommodates fast design changes, and facilitates the creation of finer features with less variation.

Here, we will discover Laser Direct Imaging (LDI), its working, its role in PCB fabrications, and its advantages in detail. Let’s dive.

Where do you get LDI Services?

If you need solid and advanced LDI services, PCBWay Fabrication House has one of the industry's best solutions. With the latest Laser Direct Imaging technology and a trained production team, PCBWay provides high-resolution PCBs with outstanding trace detail, close spacing, and impeccable alignment between layers. Their technology guarantees every board is of the highest performance and precision standards.

What makes PCBWay unique is that they can mesh high-end technology with accessibility. Whether you are developing a prototype, custom design, or large-volume production job, their LDI-capable process facilitates rapid turnaround and design flexibility without compromise. It is the perfect service for engineers, startups, and tech firms who require trustworthy, fine-line PCB manufacturing. For further details, you can visit their website.

Beyond just manufacturing, PCBWay offers a smooth, user-friendly experience. From instant online quotes to expert support and fast worldwide shipping, they make it easy to bring your ideas to life. With PCBWay, you’re not just getting LDI services—you’re getting a trusted partner in innovation.

What is Laser Direct Imaging (LDI)?

The Laser Direct Imaging approach (LDI) is a digital imaging approach at the forefront of innovation that puts patterns of circuits on photoresist-coated PCBs directly through the services of a focused beam laser. LDI does not make use of the physical photomasks or films used traditionally by photolithography since the design data projects straight from a digital file onto the PCB. This gives higher-resolution patterning with improved precision regardless of constraints in mask alignment, as shown in the figure.

LDI also has several advantages over traditional methods of PCB fabrication. It can offer very thin trace widths and intimate spacings and thus is an excellent choice for high-density interconnect (HDI) boards and complex multi-layer PCBs. LDI is also able to support greater speed of adjustments and changes to the design, and that places it perfectly for rapid prototyping and dynamic designs.  LDI by avoiding the requirement of photomasks also saves time and cost in production, offering producers a speedy and low-cost way of producing up-to-date electronic devices.

How LDI Works?

A recent process used for Printed Circuit Board ( PCB ) manufacturing, Laser Direct Imaging ( LDI ) utilizes laser technology to directly image its circuitry onto a copper clad substrate. The process has many benefits over traditional photolithography: improved accuracy, reduced processing time, and no photomask required.

1. Data Preparation:

The LDI process starts with data preparation, where the design files of the PCB, usually in Gerber or ODB++ formats, are transformed to a readable format for the LDI machine. The design files have precise information regarding the layout of the PCB, such as trace position, via position, pad position, and so on. The design is then processed by the computer inside the LDI machine to create laser instructions. This is to ensure that the laser will be able to precisely duplicate the circuit pattern on the photoresist-coated board.

2. Board Preparation:

After preparation of the data, the second step is preparation of the board. A copper-clad laminate (a sheet of copper bonded to a substrate, typically fiberglass) is coated with a layer of photo-resist, a light-sensitive material. Photoresist is a dry film or liquid photoimageable resist (LPI). Dry film resist is a solid thin film deposited, while LPI resist is deposited as a liquid and cross-linked. The layer of photoresist acts as a mask, preventing the underlying copper from being etched during the latter etching process. 

3. Laser Imaging:

In the process of laser imaging, the LDI machine exposes the photoresist to light selectively using computer-controlled UV (ultraviolet) lasers. The laser inscribes the board based on the information in the PCB design file, tracing the pattern of the circuit exactly. The UV lasers reveal the photoresist in specific areas, which creates a pattern matching the traces, pads, and vias. The laser system can function with multiple beams from different angles to be able to simplify the process considerably and speed it up if the number of PCBs is high.

The accuracy of the LDI system allows it to create dense, detailed patterns with far greater accuracy for use in more subtle applications such as high-density interconnects (HDI) and microvias, where standard methods may not be able to provide the level of detail.

4. Development:

After the board has been processed using the laser, it will be developed. Developing is the process of removing the unexposed or exposed regions of the photoresist, respectively, based on whether positive or negative resist has been utilized. For positive resist, the laser-exposed area dissolves and is washed away, and the unexposed area remains to act as a pattern for traces in the PCB. In negative resist, the exposed regions become hardened, and the unexposed regions dissolve.

The board has a patterned photoresist layer after development, which is used as a mask in the next process of copper etching, where unprotected copper is removed to create the electrical traces.

Laser Direct Imaging (LDI) in PCB Fabrication:

Laser Direct Imaging (LDI) is a cutting-edge technology used in the manufacture of Printed Circuit Boards (PCBs) with increased precision, increased speed, and increased design freedom. Using computer-controlled lasers to directly print circuit patterns on a PCB, LDI has become an indispensable tool at several stages of PCB manufacturing, usually enhancing the quality and efficiency of the manufacturing process.

1. Inner Layer Imaging:

Inner layer imaging is an essential step in multilayer PCB production for the proper transfer of copper pattern onto inner layers. Patterns need to be aligned during one-on-top assembly during lamination. LDI improves positioning precision, which reduces registration error responsible for faults or malfunctions. The LDI direct writing of the photoresist prevents degradation of the inner layers since they are printed with high precision, maintaining the integrity of the design in the multilayer PCB process.

2. Outer Layer Patterning:

In outer layer patterning, LDI offers greater resolution than traditional photomasks and is essential in creating fine-pitch traces and complex component footprints. The outer layers typically contain the large circuit traces, pads, and component leads, which have to be precise, particularly with the size of PCBs decreasing and getting denser. The ability to resolve high resolution in LDI allows traces such as those for Ball Grid Array (BGA) footprints to be produced in smaller sizes and higher complexities. A similarly high degree of detail is needed for high-speed and high-frequency applications to maintain stable operation.

3. Solder Mask Imaging:

LDI also plays an important role in solder mask imaging, where the image solder mask is made over the conductive traces of the PCB and on the pads and vias on the PCB, with holes for soldering to occur. The accuracy of LDI guarantees that these holes are made to the right size and position, thereby reducing the chances of soldering failures such as bridges or open joints. The ability to form good solder mask patterns improves end PCB performance and reliability in general by preventing difficulties during assembly. 

4. Photomask Removal:

One of the major advantages of LDI is the elimination of traditional photomasks. Photomasks are costly and labor-intensive to produce, creating extra steps in the PCB manufacturing process. These are eliminated with LDI, design being deposited directly onto the board, reducing cost and time to produce. This also results in turnaround time savings, making intricate PCB designs faster in delivery.

5. Greater Design Flexibility:

LDI enhances the design freedom, especially for HDI and microvia designs. LDI makes it possible for the producers to create small and intricate patterns, which suit modern high-performance devices that require miniaturized components. With an LDI, it is possible to have sophisticated designs and high-density utilisation, which leads to innovation in the manufacture of the PCBs.

Advantages of Laser Direct Imaging (LDI):

Laser Direct Imaging (LDI) has completely revolutionized the PCB manufacturing industry due to so many advantages over traditional photolithography technology. Without such technology being more accurate, more efficient, and more flexible, among other merits, no PCB manufacturing firm can produce high-performance, high-density boards.

1. No Phototools Needed:

One of the largest advantages of LDI is that it eliminates phototools (photomasks). Phototools need to be created for each design in traditional PCB manufacturing, which is extremely time-consuming and expensive. LDI bypasses the requirement for physical masks by having a laser write the circuit pattern onto the photoresist directly. For quick-turn prototyping or having multiple design changes, this equates to reduced setup times, less inventory, and easier design changes.

2. High Resolution and Accuracy:

LDI provides excellent resolution, enabling the imaging of line widths and spaces of 25 microns (1 mil) or smaller.  It is hard to do using conventional photolithography. As such, LDI is the ideal choice for fine line and high density PCB designs, including smartphones, medical devices, and other electronics that have shrunk in size. Its precision supports the current trend of miniaturization in electronics.

3. Improved Registration and Alignment:

With computer-aided positioning and superior optics, LDI systems enable improved registration and alignment. They utilize fiducial marks on the board to achieve precise layer-to-layer registration, a necessity in HDI and multilayer PCBs. Automatic adjustment of this sort reduces misregistration and enhances the reliability and performance of complex PCB assemblies.

4. Reduced Process Variability:

Traditional imaging methods suffer from variability caused by contamination by dust, degradation of phototools, and uneven exposure conditions. LDI avoids these by eliminating physical masks and ensuring a clean, consistent imaging process. This reduction in variability means fewer defects, higher yields, and better overall product quality.

5. Flexibility and Quick Turnaround:

LDI presents unmatched flexibility to produce. Due to the lack of photomasks, the design can be altered without delay. Hence, LDI is an excellent choice for speedy prototyping as well as production in small amounts, where speed-to-market stands as the predominant concern.

6. Lowered Environmental Impact:

LDI promotes cleaner manufacturing through the reduction of material losses associated with phototool production and film consumption. It also reduces chemical usage in development due to its cleaner, more precise imaging process. This assists in lessening the environmental footprint and conforms to modern sustainability goals in manufacturing.

Conclusion:

It is hard to do using conventional photolithography. As such, LDI is the ideal choice for fine line and high density PCB designs, including smartphones, medical devices, and other electronics that have shrunk in size. Its digital processing does away with phototools, shortening setup time and allowing for speedy design modifications—an asset in a current high-tech electronic manufacturing environment. This is perfectly suited to support rapid prototyping and low-to-moderate volume production involving high-mix.

LDI also provides higher resolution and alignment precision, critical to generating fine-line traces and multilayer PCBs with close tolerances. Through minimizing typical defects and process variability, it enhances product quality in general and increases yield. This equates to reduced manufacturing costs and more consistent end products.

Aside from its technical benefits, LDI helps ensure eco-friendly production. It avoids material wastage and chemicals, which means a minimal environmental impact. With improved technologies, LDI is not just an effective tool, but it is at present an important tool for manufacturers who want to maintain a competitive edge and future-proof.

Introduction to LPI Solder Mask in PCB Manufacturing

Hey readers! Welcome to the penetrative guide to PCB manufacturing. Hopefully, you are doing well and looking for something great. The solder mask is the most vital component in manufacturing a printed circuit board (PCB), which guarantees reliability and ensures that everything functions smoothly.

These printed circuit boards serve as the backbone for almost all modern electronics, right from the simple household consumer products like a smartphone and a laptop to diverse applications such as industrial machinery and space equipment. A PCB provides physical and electrical connections and support for the components of electronics. The most crucial area for protection is the solder mask because of its great contribution to the copper behavior of an entire circuit regarding oxidation, dirt, and solder bridging problems during fabrication.

There are different classes of solder masks, but in dense and high-precision applications, the most commonly used solder mask has been LPI or Liquid Photo Imageable. LPI solder mask is an ultraviolet (UV) light-sensitive liquid film coating applied to the PCB surface and cured partially with UV light using either a photomask or laser direct imaging system.  The curing dries the liquid, and depending on the subsequent process, can protect circuit traces with extremely tight accuracy of registration, making LPI solder mask very capable for complex electronic packaging and fine pitch electronic design.

LPI solder masks possess numerous advantages, including excellent resolution, superior adhesion, thermal and chemical stability, and fine-pitch parts compatibility. Their accurate deposition and endurance-based operation qualify them as the commercial and state-of-the-art PCB manufacturing standard. With technological advancements, LPI solder masks will remain critical in manufacturing high-performance, dependable circuit boards.

In this article, you will find the features, composition, and application process of LPI Soldeer Mask.

Where to Order PCBs?

If you want to use the absolute best and trusted option for your quality Printed Circuit Boards (PCBs), look no further than PCBWay Fabrication House. PCBWay is known and trusted by engineers, makers, and electronics companies all over the globe. With years of experience in the industry, PCBWay can deliver engineered quality PCBs for personal prototypes to build products that involve complex industrial applications, to service providers that help and facilitate other businesses.

What is great about PCBWay is the number of variables you can apply to your design. You can select multiple solder mask colors, multiple surface finishes applied over copper, board thicknesses, and flex, rigid-flex, or multilayer designs. PCBWay utilizes highly automated facilities with advanced quality control procedures to ensure the end product is always accurate and precise, even for fine-pitch, high-density boards. For its services, check its page:

It is simple to order from PCBWay. You can easily submit Gerber files using their intuitive online platform, get quotes instantly, and track orders in real time. PCBWay also has reasonable prices and a very responsive English-speaking support team, making PCBWay your partner for your PCB fabrication needs, consistently delivering speed, reliability, and value in every order.

What is LPI Solder Mask?

Liquid Photo Imageable (LPI) solder mask is a type of UV-sensitive liquid coating that goes onto the surface of the PCB. It is placed onto the surface and then hardened in a selective manner using ultraviolet (UV) light either through a patterned photomask or a direct imaging system. The selective hardening of the mask allows the mask to be developed precisely by leaving voids only in the places desired for soldering, such as pads from components and vias.

LPI solder masks are more beneficial in high-density interconnect (HDI) boards, BGA (Ball Grid Array) layouts, and fine-pitch components, among others. In high-density work, there is very little space for soldering bridges, and sometimes only the smallest bridge can have implications that will fail the entire circuit.

Composition of LPI Solder Mask:

Liquid Photo Imageable (LPI) solder mask is a specialized material made up of specific chemical components that work in unison in a series of steps, all contributing to the performance, longevity, and photoimageable qualities. Knowing this composition helps affirm why it is one of the preferred materials in current, modern high-density PCB manufacturing.

1. Epoxy or Acrylic Resin Systems:

At its core, the resin system in LPI solder masks, which is predominantly based upon epoxy or acrylic polymers, is vital for the mechanical strength, adhesion, and electrical insulation to perform repeatably on PCBs. Epoxy systems are the preferred systems because of the thermal properties and chemical resistance, which allows for use with lead-free soldering and extreme environments. Acrylic rods can be an option for applications where flexibility is important. 

2. Photoinitiators:

Photoinitiators are the UV-sensitive chemicals that help the mask harden upon UV light exposure. They are critical for the polymerization of the resin during the imaging process of the solder mask, as they allow for the pattern to develop properly. The effectiveness of the photoinitiators will define the exposure time and resolution that will be essential for tight-pitch PCBs.

3. Pigments:

Pigments are what provide the solder mask with its color (green is traditional, but also red, blue, black, white, or yellow). Pigments also have a functional purpose by blocking unwanted UV light and thus help to prevent overexposure of the area, which is not intended to be developed. Pigments also help to increase visual contrast to assist with visual inspection.

4. Solvents and Additives:

Solvents are added to control the viscosity of the liquid for controlled application of the solder mask via curtain or spray coating. The solvents evaporate during the tack-dry phase. Additives are included to improve specific properties such as adhesion, leveling of surface, UV resistance, and allow for solder mask to be tailored for different production and environmental conditions. 

LPI Solder Mask Application Process:

The application of Liquid Photo Imageable (LPI) solder mask to a printed circuit board is a multi-step process that requires care, cleanliness, and a proper application tool. Every step in the process is imperative to the performance of the mask under electrical and thermal stress during assembly and operation.

Step 1: PCB Cleaning:

Before application, a PCB must be cleaned thoroughly. Cleaning is done to remove any oxidation, dust, grease, or residues that would negatively affect the adhesion of the solder mask to the PCB. Common methods of cleaning include chemical cleaning with alkaline or acidic solutions and plasma treatment for deeper surface activation. A clean surface will not only promote better bonding between the mask and the copper or other substrate but will also reduce the possibility of delamination or peeling during later assembly and operation.

Step 2: Solder Mask Application

Once clean, the liquid form of LPI solder mask is then applied to the surface of the printed circuit board (PCB). The application is done in the following three ways:

  • Curtain Coating: The method most widely employed in high-volume production when the board is processed through a curtain of liquid solder mask.

  • Spray Coating: The method of choice when the boards cannot be easily coated using curtain coating due to the complexity of geometry or for small volume runs. Spray coating is a method that is easy to apply to any shape or size. Typical use is in production volumes for even and uniform coating onto an irregular surface.

  • Screen Printing: Now a less prevalent method, but is also performed with indications in unique design or prototype applications.

The aim is to have a uniform, bubble-free coating covering the entire surface of the PCB.

Step 3: Tack Drying (Pre-curing)

After application, the tack drying step takes place in a convection-type oven or a heat source where the board is heated to a specified temperature to almost harden the solder mask so it can hold its shape while being exposed to UV light in the next step without it flowing or smudging. The board will be flexible enough for imaging, but hard enough to avoid distortion of the mask during imaging.

Step 4: UV Exposure

The tack dried PCB is now exposed to near-UV light. This is done conventionally with a photomask that has specific openings or by utilizing a Laser Direct Imaging (LDI) method that offers a higher level of accuracy. The exposure of the solder mask initiates polymerization at the openings, hardening the solder mask in those areas only.

Step 5: Developing

During this stage, the board is exposed to a basic solution (usually sodium carbonate) to remove the exposed, soft mask material, and all that's left behind are the copper pads or vias to solder. 

Step 6: Final Cure

Lastly, the PCB will go through thermal baking or final UV curing to completely cure the chip location solder mask. This will complete the process and ensure the solder mask is completely durable, chemically resistant, thermally stable, and sturdy enough to be soldered and perform reliably in real life.

Advantages of LPI Solder Mask:

Liquid Photo Imageable (LPI) solder mask provides various benefits, making it the standard for cutting-edge printed circuit board production today. Its chemical makeup, accurate application method, and suitability for leading-edge technologies enable it to satisfy the strict requirements of today's high-density, high-performance electronics.

1. High Resolution for Fine-Pitch Designs:

The prime benefits of LPI solder masks made high-resolution imaging possible. Their applications are extremely effective on PCB designs that contain very closely spaced traces or fine-pitch components. As the size of electronics shrinks and they become more complex, there has been an increasingly higher demand for precision in all areas of design. LPI solder masks provide the highest possible accuracy in alignment and definition of openings. This means that with LPI solder masks, there will be no overlap of solder mask onto pads or vias. This level of precision leads to far lower chances of solder bridging or unwanted shorts during assembly.

2. Durable in Tough Environments:

LPI solder masks are legendary for their well-documented durability after full curing. LPI solder masks displayed extremely excellent chemical resistance, moisture, and abrasion in addition to being high-temperature resistant. They are commendably suited for applications wherein these PCBs will probably be subjected to harsh environmental conditions. Such can include PCB applications for automotive and aeronautical electronics, as well as industrial controls. LPI solder masks are very durable and withstand thermal cycles as dictated by lead-free soldering processes. This compatibility adds to LPI solder masks' strength concerning modern manufacturing processes.

3. Excellent Adhesion and Long-Term Performance:

First, the adhesion of the LPI solder mask to copper traces, as well as PCB substrate material, is better than other solder mask processes. This kind of adhesion proves extremely effective as long as the PCB is not mechanically stressed or thermally cycled, so that we can be sure that the mask will remain in place without delamination and cracking with time as a result of the nature of this adhesion and design reliability, as well as the fabrication of the solder mask. 

4. Compatibility with modern manufacturing processes:

Relatively smooth and uniform surface characteristics will enable high-performance LPI solder masks under any modern manufacturing inspection capability, such as automated optical inspection (AOI). With the defined LPI mask, the clarity of pad and solder connections during inspection is greatly improved, providing a lower probability of missed defects because of bad signal quality. Also, a reliable LPI solder mask is compatible with surface mount technology, resulting in fast, high-volume, productive assembly processes for SMT technology.

5.  Environmentally Friendly and Cost-Effective:

The process for using LPI solder mask produces less waste and is more resource-conservative compared to older types of solder mask.

 The efficiencies of the LPI process and high-volume production allow assembly manufacturers to lower their costs instead of raising their prices on future jobs while maintaining high standards of quality in their assembly processes.

LPI vs Other Solder Masks:

Features 

LPI Solder Mask

Dry Film Solder Mask

Epoxy Ink Mask

Application Method

Liquid (spray/curtain)

Laminate film

Screen printing

Resolution 

High

Moderate

Low 

Adhesion 

Excellent 

Good 

Moderate

Flexibility 

High

Moderate

Low 

Production Volume

Medium to High

Low to Medium

Low 

Cost Efficiency

High for large runs

Lower for prototypes

Very low cost

Conclusion:

The Liquid Photo Imageable (LPI) solder mask is a crucial component in today's PCB manufacturing, giving the proper accuracy, strength, and reliability for the electronic designs employed today. Its ability to facilitate fine-pitch components, withstand challenging environmental conditions, and offer durable adhesion contributes to the deployment of both high-density consumer electronics and mission-critical industrial systems.

Of course, LPI solder mask also brings some other advantages in addition to its functionality. The user benefits from improved process efficiency with environmentally friendly build processes. The effectiveness of LPI with fully automated processes such as surface mount technology (SMT) and automated optical inspection (AOI) adds to its appeal, resulting in process efficiencies and a guaranteed quality process providing reliability.

As devices become more complicated and smaller, obtaining accuracy levels and reliability will become paramount. If your application falls under the umbrella of next-gen IoT, automotive systems, or aerospace, you could not make a better choice than LPI solder mask to ensure your designs not only hold their value over time, but also offer a guarantee of performance in the real-world application.

Solder Melting Temperature and Application Guide

Solder (or brazing filler metal) serves as a filler metal in the process of brazing. In contemporary manufacturing, welding technology functions as an essential method for uniting electronic components, metal parts, and precise devices. The solder melting temperature has a direct impact on the quality, effectiveness, and suitable situations for welding. From conventional tin-lead alloys to eco-friendly lead-free options, and specialized high-melting-point solders or low-temperature solders, the differences in melting single temperature illustrate a significant interaction among material science, technological needs, and environmental policies.

The Solder Material System

Conventional solder compositions are lead-based solders mainly consisting of a lead-tin ( eutectic Sn-Pb solder) alloy, recognized for its stable composition and comparatively low melting point (with the eutectic 63Sn-37Pb solder melting at 183 degrees Celsius). It features outstanding welding and processing capabilities and is economical, resulting in its extensive application.

Nonetheless, with the rise of global environmental awareness, nations are progressively seeking eco-conscious electronic production and alternative Pb-free solder. This change has triggered the wide range of creation and use of solders without lead. These new solders must not only fulfill the fundamental criteria of traditional solders but also have extra physical properties:

(1) They must not bring in any new pollutants moving forward.

(2) Their melting temperature ought to be similar to that of the 63Sn-37Pb eutectic solder.

(3) They need to be compatible with current soldering station. They ought to demonstrate favorable processing traits.

In many countries, the creation and application of lead-free solder mainly emphasize Sn-based solders. The main lead-free solder alloys consist mainly of binary alloy systems such as Sn-Ag, Sn-Au, Sn-Cu, Sn-Bi solders, Sn-Zn, and Sn-In, as well as ternary systems such as Sn-Ag-Cu and Sn-Ag-Bi. Table 9-35 details the performance traits of lead-free solders that could possibly serve as a solid solution for conventional lead-tin solders. Of these, the Sn-Ag-Cu system is now the most commonly utilized lead-free solder.

The Scientific Essence of Melting Point for Lead-free Solder

The melting temperature of solder wire refers to the range of operating temperatures at which a material transitions from a solid to a liquid solder. For pure metals, this melting point is a fixed value. However, solder wire is typically an alloy, and its melting process generally occurs over a temperature range, from the solidus line to the liquidus line. For example, a 60% tin/40% lead-based solder begins to soften at 183°C (solidus) and becomes fully liquid solder at 190°C (liquidus). This characteristic directly influences the control window in the soldering process: if the temperature is too low, it may lead to weak joints, while excessively high-melting-point solders can damage electrical components.

Eutectic Alloys

Such as the 63% tin/37% lead composition, where the solidus and liquidus lines coincide at 183°C, allowing for instantaneous melting, which is ideal for precision soldering iron.

Non-Eutectic Alloys:

These have a melting range and require the temperature to be maintained above the liquidus line to achieve adequate wetting.

Classification of Rohs Solder and Typical Melting Temperatures

The composition design of solder is directly related to its melting temperature. Below are the classifications and characteristics of mainstream solders:

Tin-Lead Solder (Traditional Mainstream)

  • 63/37 Tin-Lead Solder (Eutectic Sn-Pb solder): Melting point of 183°C, solidifies quickly, offers high welding strength, and was once considered the "gold standard" in the electronics industry.

  • 60/40 Tin-Lead Solder: Melting range of 183–190°C, with a wider melting window suitable for the flexibility required in manual soldering iron.

However, due to the toxicity of lead, this type of solder was restricted by the RoHS Directive issued in 2006.

Lead-Free Solder (Eco-Friendly Alternatives)

  • SAC Series (e.g., SAC305): Zn Tin-Silver-Zinc alloys for soldering with a melting point of 217–220°C, offering excellent mechanical properties, though high soldering temperatures may cause PCB warping.

  • Sn-Cu Alloy (e.g., Sn99.3Cu0.7): Melting point of 227°C, cost-effective and suitable for wave step soldering, though it has poorer wettability.

  • Sn-Bi solder (e.g., Sn42Bi58): Melting point of 138°C, ideal for heat-sensitive components like LEDs due to its low-temperature characteristic, but it exhibits higher brittleness for heat-sensitive components .

Specialty Solders

  • High-Temperature Solder: Such as Pb-Ag alloy composition with a melting point of 300–400°C, used in aerospace engines or electrical equipment.

  • Low-Temperature Solder: Such as In-48Sn solder with a melting point of 118°C, used in optoelectronic packaging or biological circuits to avoid thermal damage.

The Impact of Melting Temperature on the Welding Process

The melting temperature of solder candidates is one of the most critical parameters in the welding process, directly impacting the welding quality, efficiency, equipment selection, and ultimately the reliability of the final product. From the microscopic formation of intermetallic compounds to the macroscopic control of process windows, the melting temperature is integral throughout the entire welding procedure.

Benchmark for Process Parameter Settings

In the design of temperature profiles, it is essential to optimize the temperature curves of welding equipment (such as reflow soldering ovens and wave solder melting machines) based on the melting point solder. For example, in the preheat zone, the temperature should be gradually increased to slightly below the solidus temperature of the solder candidates to avoid thermal shock that may cause deformation of components or PCB. In the activation zone, where the solder flux activates, it is crucial to ensure the temperature does not exceed the liquidus temperature of the solder flux to prevent premature melting. In the reflow zone, the temperature should rise 20–50°C above the liquidus line (e.g., SAC305 should reach 240–250°C) to ensure the solder adequately wets the pads. In the cooling zone, rapid cooling helps refine the grain hierarchy of solder joints, enhancing mechanical strength.

Wettability and Solder Joint Formation

Once the solder is fully melted, it must achieve good wettability on the substrate surface (such as copper or nickel), indicated by a contact angle of less than 90 degrees. If the temperature is insufficient, the solder exhibits poor fluidity, resulting in inadequate wetting and forming defective or "ball-shaped" joints (cold soldering). Conversely, if the temperature is too high, it accelerates metal oxidation, generating excessive dross (such as SnOâ‚‚), which diminishes the electrical hierarchy of solder joints.

Risks Associated with Thermally Sensitive Components

LEDs, plastic connectors, and IC chips typically have a temperature tolerance below 200°C. When using high-temperature solder, such as SAC305 with a melting point of 217°C, the soldering process may exceed the components' thermal limits, potentially resulting in deformation or functional failure.

PCB Layering and Warping

The glass transition temperature (Tg) is approximately 130–180°C. If the soldering temperature exceeds Tg, such as in lead-free processes reaching up to 250°C, the PCB is prone to delamination or warping.

Weld Formation

Excessively high or low temperatures can adversely affect the weld's quality. High-melting-point solders are incorrectly usedthe flowability of the molten metal increases, potentially leading to defects such as overly wide welds, uneven surfaces, and undercutting. Conversely, if the temperature is too low, the reduced flowability of the molten metal may result in incomplete penetration, narrow welds, and insufficient weld height.


Requirements for Solder Performance in Integrated Circuit

To meet the requirements of the brazing process and the performance of brazed joints, it is a solid solution that the solder used as a connecting material generally must satisfy the following basic criteria.

(1) It should have an appropriate melting point solder, which must be lower than the melting temperature of the base material being welded.

(2) It should exhibit excellent adequate wetting ability and spreading characteristics with the base material, allowing for proper dissolution and diffusion with the metal of the base material.

(3) The welding interface should possess a certain mechanical strength and maintain stable physical and chemical properties.

(4) It should be moderately priced, with low content of rare and precious metals.

The solder melting temperature is not merely a physical parameter; it serves as the "conductor's baton" for welding processes. From microscopic interfacial reactions to the macroscopic selection of equipment, temperature control plays a primary criteria through the choice of solder. In the future, with the integration of new materials and intelligent technologies, welding processes will become more efficient and precise, yet the choice of solder is Increasingly abundant,and the optimization of melting temperature will remain an enduring subject of research in this field

Introduction to PCB Heat Sinks | A Comprehensive Guide

Heat sinks are the electric routes for heat elimination from the PCB body. The digital electronic world is all about making devices compact and more powerful. This is possible only when the printed circuit boards (PCBs) are small enough to fit into the compact device. The increasing demand for power in low space comes with different challenges, of which the most crucial is the heat management of PCBs. The heat sinks are made of elements such as copper, aluminum, diamond, ceramic materials, graphite, etc., and play a crucial role in the thermal optimization of PCBs for optimal performance and long life. This comprehensive guide is about the basic introduction, heat transfer methods, key parameters, design considerations, and manufacturing techniques involved in the heat sink from the PCB point of view.

Where to Get Thermally Optimized PCBs?

PCBWay is the leading PCB manufacturer and has the honor of introducing the CRM management system to China and international companies for the first time. Before moving on to the theoretical information about PCB heatsinks, let’s discover the basic features of the platform master in providing all kinds of PCB manufacturing services, including high-heat performance PCBs. They provide all PCB-related services, including PCB prototyping, assembly, CNC, 3D printing, and much more. Customer satisfaction is their priority; therefore, they have made the process very smooth, whether it is the quotation procedure or the order tracking. 

The good thing about PCBWay Fabrication House is the quick and easy services, special deals, and discounts with the same working quality. If you want to check the current deals or special discounts, you can check their web page:

Even if the customers come with incomplete or ambiguous ideas about their projects, they can benefit from the PCBway services and book one-on-one assistance for their PCB-related queries. In short, this is the ultimate place to get all types of help, manufacturing, and work about the PCB, and a great number of positive reviews is proof of their smooth services and outstanding products. 

Introduction to Heat Sinks

Heat sinks are the essential components in printed circuit boards that dissipate excess heat from the board and help with thermal management. The electronic components on the PCBs eliminate a lot of heat during their performance, based on the type of PCB and its duty time. Proper heat management is crucial for PCBs to ensure they work in safe temperature ranges and provides the best performance even when working for hours. The following are the basic parts of heat sinks:

Heat Sink Base Plate 

It is made of high-conductive material to absorb more heat and eliminate it through the fins and also provide a solid foundation for the whole heat sink.

Heat Sink Fins

These are extended plates from the base plate, and the whole heat sink is identified through it. The common heat sink types are straight, louvered, and pin, and the density of the fins determines the thermal dissipation rate. 

Thermal Interface Material (TIM)

It is a layer of a specific material placed between the heat sink and PCB to improve thermal contact. 

Cooling Medium

The agency through which the heat is transferred to the external environment is called the cooling medium, and the most common examples are air or fluid. 

Mounting Mechanism

This is the attachment method of heat sink to PCB and include the fastener or adhesives.

The smaller size and high demand for performance from the PCBs have made the manufacturers think more seriously about dissipating the excess heat, and this has enhanced the value of heat sinks. Heat sinks are engineered near the critical components to draw the heat away, disperse it into the surrounding environment, and prevent overheating for optimal performance. 

Basic Heat Transfer in a PCB Heat Sink

It is essential to learn the core heat transfer objectives to understand the types, basic principles, and other related information about heat sinks. Heat transfer occurs through three basic phenomena, and let’s discuss each of them from the PCB point of view:

Conduction in PCBs

Conduction is the phenomenon of heat transfer from one object to another through direct contact because of the temperature difference between them. In PCBs, conduction occurs when the electrical components expel heat and it transfers toward the heat sink. The transfer rate and efficiency of the heat sink depend on the heat sink and PCB material. It is the most uncomplicated and common type of heat transfer.

The optimal place for the heat sink is exactly on the hotspots, and the most common ones are thermal spreaders, integrated circuits, resistors, etc. When the aim is to provide thermal conductivity through conduction, the manufacturer connects the heating component with the heat sink. Moreover, the fins are connected directly to the hotspot for direct heat elimination towards the external environment. 

Convection in PCBs

Convection is the heat transfer from one object to another through fluid movement. In PCBs, convection occurs when the air passes through the heat sink, which eliminates the heat by cooling it down. Basically,  there are two types of convection:

  1. Natural Convection

  2. Forced Convection

Natural convection occurs without the help of external equipment or power consumption. This process is comparatively slow, and when designing a heat sink for natural convection, these must be carefully oriented so the air can directly flow through the fins and help cool down the whole PCB system. 

On the other hand, forced convection requires an external source, such as a power fan, that takes the power but expels all the heat at a higher rate. 

Radiation Process in PCBs

Radiation is the process of heat transfer from one point to another through electromagnetic radiation. It is a good source of thermal optimization in PCBs but is a less common method as compared to conduction and convection. It is simply a phenomenon of heat elimination from an object on a PCB, and the rate of heat transfer depends on the material, surface area, and position of the component emitting heat.

The frequent way to make the heat sink more efficient for radiation is to maximize the infrared wavelength. For this, the heatsinks are made of anodized aluminum to make them more efficient with radiation heat and thermal mechanisms. Moreover, the large surface area is another measure for the same purpose. This heat removal process is useful in heavy-duty and high-temperature applications, and the most supporting point about this method is that radiation is the only heat transfer method in vacuum applications.  

Key Parameters in PCB Heat Sink Performance

When measuring the PCB heat sink performance and designing their locations, multiple factors are kept in mind, and here are some general parameters:

PCB Heat Sink Thermal Resistance (Rθ) 

Thermal resistance is the critical point when designing the heatsink. It is the material’s ability to resist the heat flow from the body to the environment. Therefore, low heat sink thermal resistance shows better heat dissipation and is preferable. A higher conductivity of the material means lower thermal resistance. Other factors to judge the thermal resistance are the component's geometry, thermal interface material (TIM), mounting pressure, and the amount of air flowing through the heat sink.

PCB Heat Sink Thermal Conductivity (k)

It is the ability of the heatsink to conduct the heat, and the unit to measure it is the W/m·K (watts per meter-kelvin). Elements like copper and aluminum have high thermal conductivity and are considered better options for creating heat sinks. Similarly, plastic and other nonmetals have very low conductivity values. 

At very high temperatures, the thermal conductivity of the material is affected, and this results in the unexpected behavior of the material. Moreover, the structure and geometry of the heatsink are another factor affecting the thermal conductivity. 

PCB Heat Sink Fin Design

The fin design is another critical point to consider when measuring the heat sink performance of the PCB. The shape, size, position, and spacing influence the thermal management through the heat sink.


Fin Design

Description

Thermal Heat Dissipation

Straight Fins

Fins extend parallel to a base plate.

Effectively cool in general-purpose applications.

Louvered Fins

Fins form a corrugated or wavy shape.

Increase the surface area to enhance heat transfer.

Pin Fins

Cylindrical fins are arranged in various patterns.

Provide a high surface area for efficient heat dissipation.

Offset Fins

Fins angle to optimize airflow and heat transfer.

Enhance cooling performance in specific applications.

Extruded Fins

Fins form by extruding material through a die.

Offer versatility and are often used for large heat sinks.

Bonded Fins

Fins attach to a base plate using adhesives or fasteners.

Allow for flexible design, suitable for various applications.


In addition to these, the heatsink surface area, position, and airflow are important factors to consider for the PCB heatsink performance. 

PCB Heat Sink Design Considerations

Several considerations are adopted for the expected performance while designing the heatsinks for the right thermal optimization on PCBs. Here are some of these:

PCB Heat Sink Geometry

This is the most basic and obvious point that designers have to keep in mind while designing the heat sink for PCBs. Every design is different in surface area, size, and airflow; therefore, the manufacturers have multiple choices according to the PCB type. Some popular heat sink designs are cross-cut, straight fin, and pin fin, and the choice of a particular design depends on the heat dissipation requirements, available airflow, and total space for the heat sink formation. 

PCB Heat Sink Thermal Interface Material (TIM)

These are the crucial gateways for the heat elimination of electronic components from the environment. They help to fill the gaps between the components and make the thermal optimization smooth. Some general TIMs are thermal grease and thermal pads, phase change materials (PCMs), thermal tapes, etc., and the right choice of TIM is the key to better heat elimination from PCBs. As a result, the thermal resistance decreases, and more heat dissipates into the surrounding area. 

PCB Heatsink Attachment Methods

The main heat elimination methods for heat sinks are convection and conduction, and these depend on the perfect contact of the heat sink with the PCB surface. This connection is accomplished using different types of mechanical fasteners, and some common examples are:

  • Screws

  • Clamps

  • Press fit

  • Clip ons

  • Adhesive-based attachments

While choosing the right attachment method for a heat sink, always consider parameters such as mechanical stress, compatibility, ease of assembly, etc. 

PCB Heatsink Manufacturing Methods

Now let’s discuss the fundamental techniques for crafting the heat sinks in the PCBs for the best thermal optimization.

PCB Heat Sink Extrusion

This manufacturing technique is applied to create the customized heat sink for the PCBs. Here, the heat sink material is usually heated aluminum or copper that is forced through the die to create long-shaped heatsinks with a good cross-section area. The resultant material is then cut into the desired size. The pluses of this technique are precision, efficiency, consistency, and customization according to the manufacturer’s choice. It is usually preferred for LED lights, consumer electronics, and commonly used appliances. 

PCB Heat Sink Die Casting

Die casting is the method in which the molten metal is injected into a mold under high pressure to shape the metal according to the PCB’s requirements. This is preferred where complex heat sink shapes are expected to create highly intricate designs and details. Moreover, this is a perfect option for high-volume production in less time. 

PCB Heat Sink Die Forging

It is a traditional way to get the right heat sink shape through the localized compressed force of a hammer or die, and the heat sink formed as a result has great mechanical strength. The parts made have high mechanical strength and thermal resistance. This technique is applied to create heat sinks for the PCB, which is expected to be utilized in high-performance fields such as aerospace or military. 

PCB Heat Sink Skiving

This method involves the formation of a heat sink by cutting the flat metal sheets. The metal is sliced and bent according to the size, area, and shape of the heat sink required. It is a comparatively complicated method and is applied to create a high-density fin structure so that thermal dissipation occurs at a high rate. This method is applied to high-duty electronic components such as GPUs, CPUs, etc.  

PCB Heat Sink Bonding

This is a relatively straightforward technique for heat sinks that involves fin attachment to the base through thermal adhesion or solder. The manufacturers have the independence to use different material types and customize them according to the PCB type and thermal requirements. The flexible design results in better performance and reliability. 

Hence, this was your guide for the PCB heat sinks, and I hope you got all the information about the topic for what you were searching for. If you want more information, you can ask in the comment section.

Laser Drilling vs Mechanical Drilling in PCB Manufacturing

The printed circuit board (PCB) is the backbone of electronic circuits, and for complex circuits, multi-layer PCBs are utilized to enhance productivity. PCB drilling is a crucial process, especially in multilayer PCB production, and involves precise via creation through laminate material. We know that vias are important conduits that bridge the gaps between multiple layers of PCBs. These are considered the conductive connections in a PCB, especially if it has multiple layers. Without vias, the multilayer PCBs have limited design flexibility and are impractical. In PCB manufacturing, there are multiple drilling types, but today I am going to discuss the comparison between the two most important methods, i.e. mechanical drilling and laser drilling.

The appropriate drilling technique selection ensures the right hole placement, optimal hole quality and reliable performance. Lasers and mechanical drilling have their own merits and demerits. Drilling is a sensitive process, and even a small mistake can damage the PCB if the manufacturer does not keep the required measures in mind. Multiple factors affect the best choice between the two but choosing the best PCB platform can make this task easy.

Best Laser/Mechanical Drilling PCB Manufacturer

PCBx Fabrication House is the leading platform that provides high-quality, low-priced PCBs and turnkey assembly services. PCBx offers all types of PCBs and has the prestige of presenting a seamless solution for laser drilling or mechanical drilling in PCBs. Drilling is a delicate process in PCBs, and we use advanced technologies for sharp, clean, and accurate drilling results, no matter if you are interested in laser drilling or mechanical drilling.

With the latest cutting-edge technology (including AI), the PCB order process is smooth, and we deliver the best PCBs with a smooth assembly and drilling process. Our top-notch automated inspection (SPI, AOI, and AXI) services make it possible for us to deliver the best products in mass production in the least time. With the 3D SPI, 3D AOI, and 3D AXI, the whole production process is under critical inspection to deliver the best product.

The latest technology not only helps to perform a smooth production process, but the top-quality drilling process is the prominent feature of PCBx services. So, if you want to get instant quoting, the most convenient ordering process, and top-quality drilling in your PCB, then you should check PCBx. Let me show you the face of the PCBx website:

The drilling process is crucial for multiple-layer PCBs, and we are offering competitive prices for drilling and multi-layer PCB production I would encourage you to try out our services and get the best quote not only for mechanical or laser drilling PCB manufacturing but also for assembly and design.

Now, let's discuss the comparison between mechanical and laser drilling and then choose the best option according to your needs.

Mechanical Drilling in PCB Manufacturing

The mechanical drilling in PCB production relies on the rotating bit tool to drill small holes in the laminated material. Usually, the drill bit can be used repeatedly because of its micro-granule cemented carbide structure. It can be reshaped and reused up to three times, depending on the type of PCB vias. In the case of mechanical drilling, the standard fiberglass and resin content laminate is used with a copper foil covering as a substrate, also termed FR4. 

The drilling element in this method consists of the pneumatic mandril, which provides almost  300,000 rpm speed to the drill; therefore, high accuracy is required for holes of small sizes. For this, the drill is mounted on the servo-mechanical system so it may move along the X and Y axes. Moreover, the particular actuator works for the PCB movement in the Z axis. As a result, the user gets a smooth, clean, and accurate output.

Mechanical Drilling Advantages in PCBs

Here is the list of common pros of the mechanical drilling process in PCBs:

  • The most common advantage is control over the hole depth with mechanical drilling. The bit tool penetrates deeper than the laser drilling hole. This is an important factor, especially if the manufacturer is working with a PCB with a large number of layers. 

  • It gives high-quality holes consistently with the same sharpness, and it doesn’t matter how many holes are drilled.

  • The mechanical drill does not have any tapers at the end; therefore, the holes are completely drilled through the substrate without any bevels. As a result, the manufacturer gets a clean knee of the wall and a sharp edge finish. 

  • This method allows the user to have a faster drilling speed than laser drilling, resulting in a good throughput level at a given time if all the preparations are done correctly. It works even better on PCBs with dense vias.

Mechanical Drilling Disadvantages in PCBs

Now, let’s have a look at the negative aspects of this technique:

  • Mechanical drilling is an old and outdated method; therefore, it is not perfect for all types of projects. 

  • When using mechanical drilling, the manufacturers have constraints on drill bit size, resulting in fewer via-size options. The narrow holes require a narrow drill, which has a great chance of breakage. For instance, if a high trace dense PCB requires less than 5 mils in diameter via holes, the required bits of diameter 0.008 inches, or 1/64ths of an inch, are too delicate for use in mechanical drilling. 

  • Usually, the bits have a large size; therefore, this technique is not suitable for the latest, smaller but more complex PCBs. 

  • If the right precaution is not taken, the mechanical drilling can cause tiny metal fragments (usually copper) that can stick to the PCB surface and affect its performance, so there is a need to clean the PCB after drilling. 

  • There is a need to deburr the PCB vias after drilling, which is a time-consuming task. 

  • It is an expensive method, and its preparation and post-processing are time-consuming. 

Laser Drilling in PCB Manufacturing

Laser drilling is the PCB drilling process that consists of a complex optics set that makes holes in different PCB layers with 200 μm or even less. As a result, highly precise and sharp drills can be drilled in the PCBs. The size and diameter depend on the laser beam opening, and the exposure time of this bean determines the hole depth. There is a set of particular lenses that perform the duty of bean concentration on a particular point for PCB drilling. This drilling type allows the beam to create even micro vias, blind vias, etc. but also eliminates the delamination. The beam shaping technology is responsible for projecting the laser on the substrate, and as a result, this energy breaks the chemical bond. This process releases the steam that generates the recoil pressure and applies the downward force to the molten material. This results in the molten material flowing out of the hole, so the manufacturers get a clean and sharp hole.

The beam ablates a fine hole in the copper layer, following the substrate materials and the beam type is selected depending on the substrate type of PCB manufacturing. The two most common laser types are:

  1. UV lasers

  2. CO2 lasers

The ultraviolet lasers are more precise and find applications in high-density interconnect (HDI) PCBs. Not only for vias, but this method is considered ideal for PCB cuttings. Conversely, carbon dioxide (CO2) lasers are less expensive but have larger wavelengths. It finds its applications in dealing with different materials in PCB, such as plastics, ceramics, and composites.

Laser Drilling Advantages in PCB Manufacturing

Have a look at some important pros of laser drilling:

  • Laser drilling ablates through a large variety of substrate materials. Therefore, has a great scope for PCBs related to different industries. 

  • It is a non-contact technology, and most processes are automatic; therefore, there are fewer chances of PCB breakage or damage. 

  • Once the laser beam settings are done and the drilling process starts, there is no need for manual changes at every point but just supervision. The laser machine performs all the duties. 

  • It has a high production rate because a large number of holes can be drilled into a single PCB at a time.

  • It is the latest technology and, therefore, suits the latest complex, smaller, and more advanced PCBs. 

Laser Drilling Disadvantages in PCB Manufacturing

Here are some negative points about the laser drilling technology:

  • A metal stop layer is required in PCBs to halt the laser drilling process. Without this layer, the stopping process is challenging. 

  • Lasers suit the smaller hole size because the chemical bond breakage requires a lot of time, effort, and energy. 

  • The aspect ratio (AR) is the hole’s copper plating indicator, and there must be great accuracy in maintaining the AR ratio; otherwise, it’s difficult to get the ideal output. The formula for the AR is given next:


AR= Depth of the hole / Diameter of the drilled hole

PCBx offers the perfect AR ratio; therefore, our clients get a clean and sharp drilling process at all times, even for mass production.

Considerations When Choosing Between Mechanical Drilling and Laser Drilling

Multiple factors affect the best choice for the particular PCB type. The following parameters will help you choose the best technology for your PCB manufacturing:

Size of Vias in PCB

One of the most crucial points to consider while choosing the drilling technique is the size of the vias. As discussed before, laser drilling allows the manufacturers to drill small-sized holes with accuracy as compared to mechanical drilling. When studying the vias size, the two most important parameters to keep in mind are:

  1. Pad to Hole Ratio=Hole Diameter/Pad Diameter​

  2. Aspect Ratio= Depth of the hole / Diameter of the drilled hole

Hence, mechanical drilling is suitable for PCBs with large vias and thicker borders otherwise, laser drilling works with smaller vias size.

Through Hole Vias in PCB

This is the type of vias that goes throughout the PCB while manufacturing and the uncomplicated type of vias because there is no need to take care of the particular layer length. For the PCBs where the manufacturer has to create multiple through-hole vias, mechanical drilling is a better option due to its superior control and grip in depth. On the contrary, if the via size is small then you have to choose laser drilling. 

Substrate Type in PCB

The drilling technique must be according to the type of substrate and other PCB material. For instance, laser drilling can cause thermal stress or delamination in the substrate like FR-4 (Fiberglass) but for polyamide, laser drill is a good choice. 

Mechanical drilling is effective for substrates like FR-4, metalcore, polyimide, etc but for the flexible substrate, laser drilling is preferred. 

Cost of Drilling in PCB Manufacturing

The cost is another fundamental criterion for choosing the best drilling technique for your PCB. Mechanical drilling and laser drilling are distinct each with varying operational costs. Although laser drilling provides more production and can deal with small vias effectively its processing cost is high and due to its complex handling, experts are required.

On the other hand, mechanical drilling is slow but it uses traditional machinery and costs less but the regular maintenance of drill bits and machine make it expensive for bulk orders. PCB manufacturers have the machinery for mechanical drilling which does not require much technical skills so usually, it costs less as compared to laser drilling. 

Hence, the cost of any of these methods depends on the number of PCBs, via size, via type, and other parameters. 

Conclusion

In PCB manufacturing, mechanical drilling and laser drilling are two of the major drilling techniques that are widely used in different PCB types. Mechanical drilling is a conventional, easy, and accurate drilling method that is useful for larger via size, hard substrates, and high AR, and pad hole ratios. On the other hand, laser drilling is the latest, cleanest, and most automated drilling technique. Different types of vias and their size play a role in choosing the right drilling technique. Each method has its demerits and drawbacks, and I hope I’ve cleared up different points. Now you can choose the best technique according to your PCB. If you want more assistance, you can contact us directly.

Introduction to the PCB Etching Process

Hello everyone, I hope you all are doing well. In today’s tutorial, we are going to discuss the PCB Etching process, a fundamental step in PCB manufacturing. The PCB Etching process is used to remove the unwanted copper from the PCB surface to reveal the desired circuit pattern.

As we know, a PCB board has a complete copper layer in its raw form. We design our circuit in the software(i.e. Eagle, Altium, Proteus etc.) and place the pattern on the PCB board. This circuit pattern is normally protected by the tin plating, as shown in the below figure:

Now, there’s a need to remove the extra/unwanted copper layer from the PCB board and this process is called the PCB Etching Process. PCB Etching is carried out in various ways and the most commonly used is the Chemical Etching Process, where a chemical named Ferric Chloride is used to remove the copper. A completely Etched PCB is shown in the below figure:

Finally, we can remove the tin layer, polish the leftover copper layer (of our circuit), drill the holes and our PCB is ready for component placing & soldering.

Where to Order High-Quality Etching for PCBs

PCBway is the leading PCB manufacturing platform that offers all PCB services, from fabrication to assembly, in mass production with instant quotes. We ensure a smooth order process and one-on-one assistance for all your PCB manufacturing services, with the best value in direct pricing. We use modern technology and processes for PCB etching; therefore, we provide a wide range of etching techniques, including laser etching, chemical etching, and much more, to ensure the exact product you are searching for. 

At PCBway Fabrication House, they provide real-time fabrication tracking for your orders so you can get the most satisfying and quick ordering process. Our professional workers know etching is a crucial step in PCB fabrication, and with the modernization of PCBs, they are becoming compact and complex, so etching provides accuracy and precision in the circuit design. Therefore, they follow the best practices and always get positive feedback for the services. For more information, follow the website’s link, and here is the main page:

The safe payment method and worldwide delivery are our prestige to satisfy the customers and work on bulk orders with the buyer’s protection. We deal with every type of PCB and provide multiple packages to grab the attention of every type of buyer. 

In this article, I am going to discuss the introduction, types, workings, and other basic information that you must know before you get started with the etching process. 

Introduction to the PCB Etching Process

PCB etching is a highly intricate process in PCB fabrication that involves the removal of unwanted material from the PCB surface. It is the controlled dissolution or erosion of unwanted copper where the specific PCB areas of the copper layer are removed to get the required pattern. It is also termed PCB printing, where circuit patterns are designed on the surface for the electric components. 

Before starting the PCB etching, there is a need to create the layout of the desired design for the board. Great care is required to create the exact design and layout, and then, it is transferred onto the PCB through a process known as photolithography. During this step, the PCB is coated with light-sensitive materials, and the pattern is then transferred to the board using light. As a result, the blueprint of the design is ready to be etched with sharp results.

PCB etching is part of the manufacturing stage of PCBs, and it takes place just before the electronic components are mounted on them. This crucial part forms the pathways necessary for PCB operations by defining the electronic connections. It is considered the last stage of PCB fabrication, and then the board is moved towards the assembly stage.

PCB Etching Processes

As discussed before, etching is the fundamental part of PCB manufacturing. For that reason, various etching techniques are employed for the specific type and material of the board. Understanding each of them ensures the manufacturer gets the required output and sharp design. Etching is broadly characterized into two major classes:

  1. Wet etching

  2. Dry etching

Let’s discover both these classes and the methods related to them. 

Wet Etching

The wet etching removes the undesired material from the PCB through chemical reactions. The next section will elaborate on its workings:

Wet Etching Working on PCB

An etchant is a chemical substance that is used in the wet etching process to react with and dissolve the excessive  material on the masked PCB. It is usually in liquid form; therefore, this type of etching is known as wet etching. Mainly, the etchants used in this method are acids, bases, or other solvents, and the selection of the right etchant depends on the type of PCB, masking, and some other important parameters. The following steps are required in wet etching:

Surface Preparation in Wet Etching

The patterns we see on the PCB are formed by a layer of metal or oxide on the surface. At the start, a plain layer of this material is coated on the PCB along with the photoresists (coating layer) through photolithography. As a result, only the dischargeable areas of metal or oxide are exposed for the etching. 

Immersion in Etchant

Now, when the board is ready for the dissolving process, it is immersed in the etchant bath, where the  exposed material undergoes the reaction process. Usually, the metal layer made of copper and ferric chloride is the etchant. This is a relatively time-consuming process, and the total time depends on the type of etchant used in this step. As a result, the underlying layer starts showing. At this point, it is important to take the board out of the etchant solution bath.

Rinsing and Cleaning in Wet Etching

After removing the substrate from the etchant solution, the board is thoroughly washed with water or other neutralizing agent to stop the chemical reaction.  

Photoresist Removal in Wet Etching

This is the final step in this process, in which the photoresist layer is stripped away from the board and the user sees the desired pattern on the board.

Wet etching is a simple and effective method to get a precise design, but it requires a lot of care to avoid over-etching or underlying layer damage. Generally, the wet etching is isotropic, which means it etches in all directions. It requires a less complicated method and does not have strong ions; therefore, it has a low risk of board damage.

Types of Wet Etching Processes

The following are the most common wet etching types:

Alkaline Etching on the PCB

The alkaline etching, or alkaline permanganate etching, utilizes an alkaline solution, usually NaOH (sodium hydroxide) and potassium permanganate (KMnO4). The solution dissolves the copper from the PCB, and this process is known for providing uniform etching at a high etching rate. 

Usually, the manufacturers select this etching type in high-pressure and conveyorized chambers to improve efficiency and reaction rate. It is a good option for etching PCBs with an uncomplicated etching design and larger surface areas. Exposing the PCB to the refreshed etch spray within the chamber helps the manufacturer achieve less toxicity than with many other etching processes.

Acidic Etching in PCB

Acidic etching on PCB involves etching away unwanted copper from the surface through the chemical reaction of the acidic solution. The acidic solution can be applied to the PCB through different means, such as dipping it in the bath, spraying the solution on the board, or brushing it on the surface. 

Once the acidic solution dissolves all the discardable copper layer areas, it is then washed and dried completely to stop the chemical reaction. Generally, the acidic method is considered best for the inner layer as it helps minimize the lateral erosion of the etched material of the masked metal layer. The chemical reaction is more controlled in this type; therefore, it provides an intricate and refined circuitry design. Manufacturers consider this method for smaller designs and dense boards because it provides a fine line width.

Dry Etching in PCB

Dry etching is a technique in PCB that involves the removal of unwanted metal coating areas through reactive gases or plasma instead of liquid chemical reactions. It is a highly precise method to create sharp patterns and fine features on PCB. The most common methods of dry etching are described next:

Plasma Etching on the PCB

Plasma etching has been used for PCBs since the 1960s but was not a prominent technique until the 1970s. This method was considered useful for reducing liquid waste disposal and getting sharper results as compared to wet etching. Another prominent benefit of using plasma etching is that it uses excitation and dissociation techniques to remove a particular part without causing damage to PCB surfaces. As a result, it is considered a good option for sensitive and delicate PCBs.

The method involves the use of a plasma system, also known as the plasma chamber. A high voltage is applied to the reactive gases such as oxygen (O2), chlorine (Cl2), argon, fluorine, etc., which break down the molecules into the constituent gas atoms. For this, the plasma system has a radio frequency source that produces electromagnetic waves. Some of these atoms are ionized (acquire charge) and then react with the exposed metal layer. As a result, the discardable copper molecules are broken down and removed. Mostly, the frequency range is 13.56 Mhz, 40 Khz, 80 Khz, 100 Khz, and 2.45 GHz. 

The process does not involve any chemicals and is a dry, clean, and effective method for etching. The positive points of this method are that it is a clean, controlled, and precise method for etching that can be applied on small scales. Unlike some other techniques, there is no risk of vias contamination or solvent absorption. Moreover, it works better on high-density printed circuit boards, often utilized for fine-line circuitry. On the contrary, it is an incredibly costly technique and is not profitable until the etching is done in large quantities regularly. The chamber system requires maintenance and expertise. 

Laser Etching on the PCB

Laser etching is also termed laser ablation or laser direct imaging (LDI) and was used at the start of 1987. It is the process in which a high-power laser beam is incident to the PCB surface to remove the unwanted copper layer and get pinpoint accuracy. It is a computer-controlled method, and the excessive copper is either evaporated entirely or flaked off.

On a larger scale, laser etching has the following sub-types:

  • Fiber Laser

  • Ultra Violet Laser

  • CO2 Laser

Ventilation, eye protection, protective clothes, laser beam reflection maintenance, and limited direction viewing are some of the fundamental precautions required to apply this method. A benefit to using this method is that the number of steps in the whole process is very minimal if all the precautions and machinery are ready to use. No ink, acid, toxic material, or wet chemical is required for this process. 

The disadvantage is, that etching the large board is challenging. Moreover, it requires a lot of investment at the start to get the equipment and system ready. The operational cost is also high in this process. 

Comparing Wet Etching and Dry Etching

The following table shows the difference between wet and dry etching for the printed circuit board:


Feature

Wet Etching

Dry Etching

Process

A liquid chemical solution is required for etching

Gas, plasma, and lasers are required for the etching

Etching Material

Liquid chemicals (e.g., acids, alkaline solutions).

Reactive gases or plasma.

Material Removal

Isotropic (removes material uniformly in all directions), can lead to undercutting.

Can be anisotropic (directional etching), providing more precise control.

Equipment

Requires chemical baths, masks, and washing stations.

Needs vacuum chambers, plasma sources, and more sophisticated equipment.

Cost

Generally lower cost due to simpler equipment.

Higher cost due to complex and high-precision equipment.

Applications

Preferred for use for large-scale material removal in simpler PCB designs.

Preferred for high-precision applications, especially in advanced and complex PCB designs.

Advantages

  • Cost-effective

  • Straightforward

  • Widely used.

  • Precision control

  • Minimal undercutting

  • Suitable for fine features.

Disadvantages

  • Can lead to undercutting

  • Less precision

  • Chemical waste disposal is required.

  • Expensive

  • Requires complex equipment

  • More energy-intensive.

Etching is one of the most basic steps in PCB manufacturing, in which the excess copper layer is removed from the PCB surface to get the desired circuit design. A copper layer is applied to the PCB, and, a mask of unreactive material is applied to the areas required on the board. The unneeded part is then allowed to react with the etchant and is dissolved. After that, the solvent is then removed and dried if required, and masking is then removed. As a result, sharp and fine designs are obtained. Etching is broadly classified into wet and dry etching. Examples of wet etching include alkaline and acetic etching, whereas dry etching includes plasma and laser etching. The choice of method depends on the board size, density, type of board, etc. Each method has its merits and demerits, and we have discussed all the basic points to clear up the topic.

Factors Affecting the Prices of PCB Manufacturing & Assembly

A printed circuit board(PCB) is the most important part of an electronic device. A high-quality PCB is necessary to make a safe and durable device. PCB manufacturers should strive to maintain high quality at a low price. To achieve this goal, some matters should be taken into account.

Some key factors affect the prices of PCB manufacturing and assembly. PCB price depends on size, number of layers, quantity, etc. The material that we choose for PCB also affects the cost. The PCB printing process also matters in this regard. For example, some PCB manufacturers print PCBs manually while some control the whole process with CNC machines. Manual PCB printing is cheaper than CNC machine-printed PCBs. PCB manufacturing is a complicated task that needs experience and technology. A trusted PCB partner is essential for the electronics business.

Where to order cost-effective PCBs?

PCBX is an industry-leading PCB prototype manufacturer. Here you will get a One-Stop PCB Solution from Design to Mass Production.

PCBX specializes in providing 24-hour quick-turn PCB. We offer consistently low prices but high quality. We have 19 Years of Experience with proven expertise in prototype & production. Our Strict QC and advanced inspection ensure high reliability and stability. We have Advanced Automated Inspection (SPI, AOI, AXI) Services designed to ensure the utmost quality and consistency throughout the PCB production.

We integrate innovative technology including AI with efficient processes to deliver high-quality PCBs and complete product assemblies at competitive prices. This combination Minimizes rework and waste, saving on costs.

If you are looking for high quality at a low price, PCBX Fabrication House is the perfect place for you.

Following is a screenshot of the PCBx website’s home page.

We have a special offer of $1 for 10 PCB prototyping, and $15 for 10 PCB Assembly, without compromising on quality. We also give free PCB assembly coupons. You can see the offer on our website as shown in the following picture.

In this article, we will discuss the Factors Affecting the Prices of PCB Manufacturing & Assembly. We will also try to find a balance between cost and quality.

Delivery time

How does shorter delivery time increase manufacturing costs?

Delivery time plays an important role in the manufacturing cost of PCBs. Urgent or express delivery adds more to the cost. When the customer demands urgent delivery, the manufacturer needs to employ extra labour. Workers may need to do overtime. Additional machineries are put into operation. These will increase the overall manufacturing cost.

Due to shorter delivery time requirements, manufacturers often need to adjust production schedules and processes to ensure timely order completion. They may need to rearrange production lines, prioritise urgent orders and accelerate production speed. As a result, costs associated with production adjustments are increased.

After manufacturing the PCB, then comes the question of delivery. Urgent delivery needs special arrangements. Air freights and express delivery services add more to the cost.

PCBX offers a flexible assembly time frame. It can range from as little as 24 hours to a few weeks. You can select the time option that best suits your schedule and budget. We want to ensure transparency. This is why our turn-time policy begins once all the necessary components are ready and all the required PCB files are complete for our assembly work. These files include Gerber files or other PCB file formats, Centroi(PNP file), BOM, and any other essential data, documents, images, or photos. This approach accounts for the complexity involved in determining the turnaround time for PCBA services.

Complexity of design

The design plays an important role in the manufacturing cost of a PCB. The more complex the design is, the costlier it becomes. Complex design usually means the components are densely placed and a lot of traces and vias are very close to each other. This type of complex PCB needs extra care during manufacturing. Complex circuit boards may require larger board areas. The number of layers may also increase. All of these factors will eventually increase the production cost of the PCB. So, it is wise to keep the design as minimalistic as possible. If the whole circuit can be accommodated in a single-layer board, there is no point in making it double-layered. Traces should be placed cunningly to save more place. 

We want to make your PCB designing task easier. We have the PCBX designer to help you with the design. It is an online PCB designing platform. It is quite easy to learn. It takes not more than 5 minutes to learn this tool. No matter what device you use, you can always run this tool. You can import circuit files from other PCB Designer software into PCBX for viewing, editing, and modifications. Following is what the PCBX designer looks like.

PCB Size

Bigger PCBs usually need more substrate materials. They also need more copper foil. All of these materials increase the cost. For high-density boards, the increase in material costs can be significant.

Larger PCBs may need a series of complex manufacturing processes. They depend on larger production equipment, such as larger cutting machines, and larger copper plating holes or slots. This increases manufacturing complexity and costs. The following picture shows a PCB which is bigger than usual.

PCB shapes

PCBs are usually rectangular. But often they are of other shapes. Such as round PCB, Christmas tree-shaped PCB etc. To cut circuit boards in unusual shapes, additional processing steps or customized processes may be required, further adding to manufacturing costs. The following picture shows a PCB having an exotic shape.

Larger PCBs may lead to higher shipping costs. Due to their larger size, they need larger packaging boxes or additional protective measures to ensure the safe transportation of the products. Transportation of big-size PCBs may pose some challenges. As a result, PCB suppliers may need to pay additional charges, such as oversize cargo fees or higher shipping costs.

Number of layers

An increase in the number of layers means the consumption of substrate materials, copper foil, insulation materials, etc., also increases. Thus the number of increased layers raises material costs. The following picture shows the standard composition of a multilayer PCB.

Multi-layer PCBs need a more complex manufacturing process. In multi-layer PCBs, additional processing steps may be required. These steps include lamination of copper foil layers, drilling, and alignment of inner layer circuitry. These processes add to the complexity and difficulty of manufacturing, consequently increasing manufacturing costs.

PCBs must ensure stable signal transmission. This is why multi-layer PCBs require precise alignment and connection between each layer. Multi-layer PCBs have vias between layers to interconnect the components of each different layer. Electroplated vias are very common in these PCBs. To accommodate all these features, multi-layer PCBs demand higher levels of manufacturing technology and equipment. This also contributes to higher manufacturing costs.

With the help of modern technology and expertise, PCBX is capable of manufacturing multi-layer PCBs consisting of up to 8 layers. 

Substrate Material

Different types of substrate materials have different prices. The substrate material you choose directly manipulates the price of your PCB.

For example, commonly used FR-4 fibreglass composite materials are typically cheaper than high-frequency materials like PTFE. The following figure depicts the placement of substrate material in PCBs.

There are certain special applications of PCBs. Many PCBs need to operate in high-frequency, high-speed, or high-temperature environments. For this purpose, special substrate materials may be required to meet performance requirements. Generally, these special substrate materials are more expensive.

The price of PCB directly depends on the thickness of substrate materials. There are some commonly used high-frequency substrate materials with relatively high prices. RO4350, RO5880, etc. are mentionable among those.

Trace Width and Spacing

Finer manufacturing methods and higher-end production equipment are needed for smaller trace widths and spacings. Reduced trace widths and spacings may require the employment of more sophisticated lithography methods and drilling tools, which raises the cost of production. Smaller trace widths and spacings could also result in more complicated production processes and longer processing times, which would raise manufacturing prices even more.

Reduced Yield Loss 

During the manufacturing process, smaller trace widths and spacings may result in a greater yield loss. There might be more scrap or faults during production as a result of the reduced trace widths and spacings, which would raise production costs and reduce yield. Smaller trace widths and spacings may also raise the failure rate during manufacturing, necessitating the need for additional steps to lower scrap rates, such as stepping up inspections or changing production procedures, which raises the cost of manufacturing.

The following picture shows trace width and trace spacing.

Drill holes

Increased Processing Costs

Another thing that heavily influences the price of your PCB is the number and size of drill holes. Smaller drill holes need smaller-sized drill bits. It increases the processing cost of PCBs. There may be some specialized PCB requirements, such as blind vias, buried vias, or controlled-depth holes. Special drilling processes are often required to meet these demands. These special drilling processes typically require higher-level processing equipment and more complex operational steps, thus giving rise to processing costs.

The following picture shows a PCB with different sizes of drill holes.

Increased Material Loss

Drilling processes sometimes lead to material loss. Increased material loss rates result from more material being removed and sliced away when there are more drill holes. Furthermore, additional drill holes might be needed for some specific PCBs, such as high-density boards, in order to achieve complicated circuit layouts, which would further increase material loss rates. To meet specific PCB criteria, including blind vias, buried vias, or controlled-depth holes, unique drilling techniques could be required. Processing expenses are increased because these unique processes usually call for more sophisticated operational procedures and sophisticated processing equipment.

Higher Loss of Materials

Material loss can occur during drilling operations. Increased material loss rates result from more material being removed and sliced away when there are more drill holes. 

Surface Treatment

copper is oxidized and deteriorates in the presence of air. Oxidization seriously affects the electrical properties and solderability of PCBs. The implementation of PCB surface treatment is important for the improvement of the reliability and shelf life of PCBs. The quality of metal-to-metal joints depends on surface treatment These treatments also contribute to the higher manufacturing cost of PCBs.

There are 8 kinds of PCB surface treatment methods. These are-

  1. HASL, hot air solder levelling

  2. OSP, Organic coating.

  3. ENIG.Chemical gold.

  4. IAG. Immersion Silver.

  5. ISN. Immersion tin.

  6. Electroplated Nickel Gold.

  7. Electroless Palladium.

  8. ENEPIG, Electroless Nickel Electroless Palladium Immersion Gold.

The following picture shows different PCB surface finishes.

The costs of all these surface treatment techniques are not the same. For example, organic coating is cheap. On the other hand, palladium is a valuable metal. So, the Electroless Palladium process is expensive. Expiration dates of various surface treatments are different. You have to select the surface treatment according to your application.

How can you decrease PCB manufacturing costs?

Here are some tips to follow if you want to cut down on the manufacturing cost of PCBs

Right placement of components

Component placement of PCB should be done in such a way, that you can connect them to each other by the shortest possible path. When you convert a schematic to a PCB layout, please pay attention to the components that are connected to each other. Place the connectable components close to each other. Try to keep the traces as short as possible.

Aim for the lowest number of layers possible

PCB cost increases proportionally with the number of layers. So, try to accommodate all the traces, vias and components in the lowest number of layers possible.

Remove unnecessary trace spacing

It is essential to maintain an optimum distance between the traces to avoid DRC errors. However, traces should not be placed so far from each other that the total board area becomes cumbersome. Try to place the traces as close as possible to each other without violating DRC rules.

Follow DFM guidelines

DFM stands for design for manufacturability. DFM guideline is a set of rules for cost-effective and efficient manufacturing. By following this guideline, you can optimize the sizes, materials and tolerances of PCBs to reduce costs.

Common Issues Faced in PCB Designing

PCB stands for printed circuit board. You will find PCBs in pretty much all electronic devices. It is usually green/blue in color. The PCB is a circuit in a board that permanently holds all the components of a circuit.  It is the main part of an electronic device. This board controls and regulates the function of the whole device. A circuit may work perfectly in a breadboard. But breadboard circuits are not suitable for use. It will only be eligible to be used in a ready-made product if implemented in a PCB. This is why PCB designing should be done with utmost care. 

Where to order error-free PCBs

It takes a lot of knowledge and expertise to manufacture good-quality PCBs. PCBway is a trusted PCB manufacturer. While their head office is located in China, they ship PCBs worldwide. The following image shows the home page of PCBway.

PCBway Fabrication House is the best PCB manufacturer for professionals and hobbyists. There you can not only print your PCBs. You can get consultancy regarding the whole manufacturing process.  Together with a top-notch design and an expert manufacturer, you can produce a high-quality and durable PCB. The following pictures shows how the order page of PCBway looks.

PCB design should be an accurate process. It involves several critical steps. Different challenges may arise in each step of this process. It is important to detect and solve these problems at the early stage of manufacturing the product. Otherwise, we cannot guarantee a reliable electronic gadget.  This article discusses the common problems faced in PCB designing and practical solutions to solve these.

Misplaced components

Problem

This problem often occurs when the designer is a newbie. The wrong placement of components causes some problems. Due to this mistake, the size of the PCB increases unnecessarily. That costs unnecessary money. Soldering becomes difficult if the components are haphazard. Electromagnetic interference (EMI) may also occur and overall signal integrity may also be affected. Misplaced components also result in the following problems:

  • Difficulties in soldering during the manufacturing process
  • Electromagnetic interference (EMI)
  • Signal integrity issues.

Solution:

We should place components in a PCB wisely. The components should be arranged in such a way that the traces will be as short as possible. The components that are supposed to be directly connected, must be placed close to each other. The following image shows a decent arrangement of components in a PCB.

90-degree traces

Problem:

Making 90-degree traces is a big no-no for pro-level PCB designs. The sharp edge created by this type of tracing creates extra stress on the traces. These traces are more likely to crack or break. The life span of such badly designed PCBs is less than usual. The corners of a right-angled PCB have higher electric field density than standard ones.

Right-angle PCB traces affect signal integrity. The effect of a PCB trace's right-angled corner is the same as that of a transmission line coupled to a capacitive load. This is called parasitic capacitance. As a result, the transmission line signal's rising time is slowed down.

Solution:

Designers should always avoid right-angled traces. In PCB designing software like Proteus, there are functions for making curved traces. We must use those to make our traces curved and not susceptible to cracks after long-term use. The following image shows the difference between a bad and a good trace.

Poor Signal Integrity

Problem:

PCB designers must ensure signal integrity. Signal transmitting across the PCB should not distort. Poor signal Integrity is caused mostly by wrongly designed traces, crosstalk, impedance mismatch etc. Signal distortion causes transmission errors.

Solution:

Modern PCB designing platforms have many important tools that help PCB designers maintain good signal integrity. By knowing how to use them properly, you can avoid errors like uncontrolled line impedances, propagation delays and signal attenuation. 

The following figure shows a relationship between coupling traces and SI(signal integrity parameters.)

Electromagnetic Interference (EMI)

Problem:

EMI causes noise and signal interference. Noise degrades the performance of a PCB. EMI increases with frequency. This may cause many problems in high-frequency circuits and designs where components are congested.

Solution:

EMI can be handled with a combination of design strategies. One method is to use ground planes. We have to place ground planes in such a way that they absorb and redirect electromagnetic emissions.   It is also possible to reduce EMI by reducing the current loop area. 

It is also important to Shield critical components and traces.  Additionally, careful routing of high-frequency traces away from sensitive analog signals can minimize interference.

Heat is generated in PCBs in several ways. Some prime sources of heat generation in PCBs are the active devices or chips that generate heat. Another source is created when an RF power is applied to the circuit. In the case of a double-layered PCB, the copper has extremely high thermal conductivity. On the other hand, the substrate is a thermal insulator that has a very low conductivity. A good-quality PCB must Have a high heat flow. There must be sufficient heat sinks around active components. It is important for keeping the circuit cooler by more efficient heat transfer from the heat source to the heat sink.

The following picture shows some  EMI shielding films.

Power Distribution Problems

Problem:

Structurally a PCB can be perfectly alright. Still, it will be useless if the power supply is not adequate. Power distribution should be according to the requirements of each and every component. There may be different voltage and current requirements for different components of a PCB. For example, a PCB may consist of a microcontroller that operates at 5V, but there may be a motor driver that operates at a different voltage level. So, different amounts of voltage and current must be supplied to different parts of the circuit. It is necessary to design a reliable power distribution network. There are PDN analyzers that can detect anomalies in the PDN.

DRC error

Problem:

If you know how to use a PCB designing software, you already know this term. DRC stands for Design rule check. DRC error occurs when you do not maintain the minimum trace-to-trace distance defined by the software. For example, the minimum spacing between two traces of a 2-layered PCB is 6 mils (mil=1/1000 inch). If any two traces of your PCB layout are closer than this, the software will show a DRC error. The same error messages will appear also when-

  • Traces are overlapped with each other

  • The power plane and the GND plane touch one another

  • The minimum standard distance between a trace and an adjacent via is not maintained. 

We should never ignore DRC errors. If we print a PCB without solving DRC errors, chances are high that it will blow away after powering up.

Solution:

There should be no DRC error in the PCB layout. Each DRC error detected by the software should be corrected before printing the PCB. You have to edit your design to meet the requirements of the software. You may need to adjust the sizes of the traces and vias to comply with the rules. The following image shows the DRC tool of a  PCB designing software.

Manufacturing Defects

Problem:

You may design a flawless PCB, but manufacturing errors can still occur. You can see many short circuits and broken traces. Sometimes it becomes also impossible to read the texts written on the silkscreen. The following picture shows a broken PCB trace.

Solution:

A good collaboration with the manufacturer may help you solve these manufacturing defects. The customer should provide clear and detailed documentation. It is essential to include the fabrication drawings and assembly instructions. It is helpful to perform a manufacturability (DFM) check to identify potential issues before production. Automated optical inspection (AOI) and in-circuit testing (ICT) during manufacturing can also find defects early.

Grounding Issues

Problem:

A well-designed ground system is required for Modern high-speed electronics. PCBS need to operate at their best performance. If the PCB ground is not properly implemented, the circuit board may experience many different problems with noise and electromagnetic interference (EMI).

Sometimes the ground net in a PCB design can appear confusing. Yes, there are many connections, but since most designs will have one or more ground planes in their layer stacked up, you just add a via to the ground, and the work is done. Right? Theoretically, that is correct, practically, there are lots more that need to go into your PCB grounding technique to build a good power delivery network.

Solution:

A single, continuous ground plane is typically the best approach for minimizing ground loops. The following image shows a PCB layout with properly designed POWER and GND planes.

Soldering Issues

Problem:

Soldering issues such as cold joints, bridging, and insufficient solder can lead to unreliable connections and component failures.

The following image shows an example of an accidental short circuit.

Solution:

Designing with manufacturability in mind can help prevent soldering issues. Ensuring appropriate pad sizes and clearances for components can facilitate proper soldering. Specifying the correct solder mask and paste layers in the design files is also important. Automated soldering processes, such as reflow soldering, should be used whenever possible to ensure consistent and reliable solder joints. Inspecting solder joints using AOI and X-ray inspection can catch defects before final assembly.

Inadequate Clearance

Problem:

Inadequate clearance between traces, pads, and components can lead to shorts and an increased risk of crosstalk, affecting the PCB's reliability and performance.

Solution:

Following the clearance guidelines provided by the PCB manufacturer is essential. Maintaining adequate spacing between traces and pads can prevent shorts and crosstalk. Using the DRC tool in the CAD software to check for clearance violations can help identify and rectify issues before fabrication. Also, consider the voltage levels and environmental factors like humidity and temperature. It can guide appropriate clearance settings.

Multilayer Design Complications

Problem:

Designing multilayer PCBs introduces complexity, such as ensuring proper layer stack-up, signal routing, and maintaining signal integrity across layers.

Solution:

Planning the layer stack-up early in the design phase is critical for multilayer PCBs. Assigning specific layers for power, ground, and signal routing can help manage complexity. Using blind and buried vias can optimize space and routing options. Ensuring proper alignment of vias and traces across layers is essential for maintaining signal integrity. Simulation tools can assist in verifying the performance of multilayer designs and identifying potential issues.

Failure to Consider Manufacturing Tolerances

Problem:

Tolerance means the maximum deviation from the design at the time of the manufacturing process. There are always big differences between theory and practice. Your design may be perfect in your software, but you have to consider manufacturing tolerances in practice. If we do not take it into account, our PCB may fail.

Solution:

It is best to check the manufacturing tolerances of the PCB manufacturing company. The following image represents PCBway’s manufacturing tolerance guideline. To learn more about PCBway's manufacturing tolerance policy, you can click here.

Environmental Factors

Problem:

While designing a PCB, it is necessary to take environmental factors into account. You must consider the temperature, humidity, and atmospheric pressure of the environment where it is likely to be used. For example,  a PCB designed for an industrial purpose should be more robust than a PCB of a home appliance.  PCBs are likely to damage early if they are not compatible with their surroundings.

Solution:

First of all, we have to select the components according to their specifications and operating temperatures.  For industrial products, all components and the board itself should be industrial-graded. For better heat dissipation, use thermal vias, heat sinks etc.

Following is a chart of high TG materials used by PCBway.

Conclusion

PCB manufacturing is a process that needs a lot of scrutinization, time and dedication.  PCBs are often printed on a trial-and-error basis.  It should be our goal to save as much money and time as possible while not compromising the PCB quality. We should correct all DRC errors before printing a PCB. We need to provide a proper thermal management system, and proper shielding for removing signal interference. We should not tend to make the design on an ad-hoc basis. Rather, we must always try to make a durable PCB. We should choose a dependable manufacturer.

Advanced Manufacturing Materials for PCB

Hey there, I hope you are having a good day. Printed circuit boards (PCBs) are a popular topic in the electronic world and we also know that PCBs have revolutionized circuits. They not only provide a solid base but the material used in the PCBs helps the circuit to function properly by protecting the circuit from factors like external radiation. These are present in different materials that divide the working, stability, and reliability of the circuit. In recent years, there has been a significant change in the types and strength of PCBs and this depends on the materials used in the manufacturing of these boards. We are interested in studying the advanced materials used in the manufacturing of PCBs and knowing the right type of material for the right circuit.

In this article, we’ll start from the basic introduction of the advanced material and will try to understand why it is better to replace the traditional material with the advanced one. After that, we’ll see some important categories of the advanced materials used in the production of PCBs that are important to meet the needs of the latest technologies.

Where to order PCB?

Before going forward, let me first tell you where you manufacture your PCBs with these materials. PCBWay Manufacturing House provides almost all of these materials for PCB manufacturing. PCWay provides the best services when it comes to PCB designing. I personally use PCBWay for all my PCB orders and always get the best results.

In order to place your order in PCBWay, click on the Order Now Button and insert your PCB details. On that PCB details page, you can select the PCB material for your board. The order page of PCBWay is shown in the below figure:

Advanced Material of PCBs

The transformation of PCBs in recent years is because of the high quality and advanced materials used in manufacturing and this not only has improved the life span of the PCBs but also has a major impact on the circuit performance. The advanced materials are referred to as:

"The advanced materials for PCB manufacturing are the new material or the improved existing materials used in the manufacturing and design of the latest PCBs that help to meet the requirements of the advanced PCBs."

With the advancement in technologies, there is a requirement for faster, smaller, and more efficient electronics, and that in return, has enhanced the need for advanced PCBs. These requirements are fulfilled by using the advanced and more efficient material that helps to meet the need of the time. These materials are responsible for innovating the PCBs and these are not only the trend but are the essentials that are required to meet the requirements of contemporary electronic applications.

The advanced materials are better in performance and provide high-speed data transmission from one end to the other which is the main focus of the advanced digital electronic equipment. 

PCB Advanced Material Examples

Here is a list of almost all the important advanced materials that are extensively used in the PCBs nowadays and play a crucial role in the improvements of the PCB industry:

Advanced PCB High-Speed Laminates

The traditional material is not able to overcome the advanced problems and boundaries of the bandwidth. The high-frequency circuits are introduced in the market that perform complex duties and these circuits are successful only when high-frequency PCBs are used. For this purpose, high-speed laminates are used for the manufacturing and design of the PCB. these cutting-edge laminates are the new generation of high-frequency materials for PCBs tailored for high-frequency applications.

High-Speed Laminates Properties in PCB

  • These laminates have an exceptionally low dielectric constant (Dk) that ensures minimal signal distortion. This property makes the PCB capable of dealing with the speed of light making the circuit work faster and better to match the new trends and requirements of the technology. 

  • The minimal signal loss helps this material to provide another feature to PCB which is the negligible dissipation factor (Df). It maintains the signal integrity and provides low heat dissipation. One must be kept in mind that it results in efficiently dealing with the heat problems of the circuit. 

  • The thermal stability of the high-frequency laminates is a plus point that helps to achieve the advanced level outputs from the circuit. These laminates have the physical properties to bear the high temperature without causing any change in their shape.

Examples of High-Speed Laminates

The following are suitable examples that are widely used in PCBs:

  • Rogers RO4000 series

  • Taconic CERFREE

  • PTFE (Polytetrafluoroethylene)

  • FR-4 

  • Isola Isola-Tate FR-408

  • LCP (Liquid Crystal Polymer)

Metal Core PCBs as Advanced PCB Material

The metal core PCBs (also known as the MCPCBs) are the specialized PCBs that has the metal base as the substrate. The most common metal-based PCB types are listed below:

  • Aluminum

  • Copper

  • Steel alloy

Out of these aluminium-based PCBs are the most cost-effective. One evidence of this statement is, that it has high heat resistance therefore, such PCBs have a long life. Hence, the low heat dissipation results in the better performance of the circuit for a long time.

On the other hand, if the user wants high performance then the copper-based MCPCBs are a better option than the previous one. Copper is considered one of the most reliable conductors because of the physical arrangement of its atoms therefore, using it in the PCB is the best way to get the highest performance. This is the most commonly used material for the PCBs but it is more expensive the the aluminum PCBs.

Another important metal in regard is steel which is harder than the other two options mentioned before. Because of the tightly packed structure, this type of PCB has less conductivity but the plus point is, that these have excellent heat dissipation.

As a result, the specific type of the metal core PCB is used for the specific type of the circuit by keeping the thermal and other characteristics of the PCBs. These types of materials are used in PCBs because they have features like heat dissipation, less distortion, good dimensional stability, etc.

Advanced Flexible Material for PCBs

The flexible PCBs are one of the most trending type of PCBs that have the ability to make space in any type of the circuit and does not cause any major performance change. The advanced technology has made the circuit small and more flexible, therefore, there is a need for the PCB that is flexible and can bear the load of the high calculation and processing. These are made with lightweight, thin, and flexible materials and lead to a high range of applications in all types of circuits.

These PCBs are made on different scales of size and thickness and can be bent like a rubber therefore, are considered the ideal PCBs for wearables and other such technologies. The most commonly used flexible materials for PCBs are

  • LCP (Liquid Crystal Polymer)

  • PEN (Polyethylene naphthalate)

  • PET (Polyethylene Terephthalate)

  • PI (Polyimide)

  • PTFE (Polytetrafluoroethylene)

  • Flexural FR-4

  • Coverlay films (PI, PET, etc.)

  • Metal foil (copper, aluminium)

  • Adhesives (acrylic, epoxy)

Hence in this way, we have seen different type of advanced materials that are used in the PCBs and are making them more efficient and up to date. We started with the basic introduction of the advanced materials in the PCBs and then we understood different types of the advanced material that is revolutionising the PCB industry. The high-speed laminates, metal core PCB, and the flexible materials in the PCBs are important materials in this regard. If you know other such materials that are most common and suitable for advanced PCBs then share with us through the comment section.

Introduction to Rogers 5880 PCB

Hi readers! I hope you are doing great in your fields. It’s time to learn some important points about the Roger 5880 PCB. We know that PCBs are one of the most crucial parts of the circuit at a higher level and have a major effect on the nature and performance of the circuit. We are going to delve into the details of the Roger 5880 PCB and learn from scratch why this is one of the trending options in the market. We’ll not only work on discovering the features of this PCB but will also discuss the best option for all PCB-related services.

PCBWay is one of the most popular and safe ways to design your circuit thoughts and convert them into reality. They provide the best prototyping services on one platform, and their latest technologies attract a large number of customers. This platform is not perfect for professionals, but any user who wants PCBs for a hobby, personal project, or entrepreneurship, or wants a great set of PCBs for the whole office, can get the right product from PCBWay Fabrication House.

Ordering from PCBWay.com is very easy, no matter if you have any technical skills or not. They are providing budget-friendly output without compromising on quality. Multiple options for every type of PCB with full detail and customisation options make it the best way to order and get the right product without any difficulty.

Now, let’s start learning about the Rogers 5880 PCB. 

Introduction to Roger 5880 PCB

The Roger 5880 is a microwave-laminated material that is widely used in specialized PCBs. It is used as the substrate to make highly efficient microwave PCBs. We know that microwave PCBs are the most efficient type of PCB that works under hard conditions of temperature and frequency and still provides the best performance. This can be done because of the high-quality material used in these PCBs. These are considered the ideal PCBs for sensitive fields such as:

  • Radars

  • Satellite communication

  • 5G systems

  • Automotive electronics

Roger 5880’s Unique Features

  • The main characteristic of this material that makes it unique is its composition. It is a ceramic-filled, PTFE (polytetrafluoroethylene) composite substrate that offers great performance in situations where traditional PCBs are unable to work.

  • It offers a unique blend of a low dielectric constant (Dk) and a low loss tangent (Df) and, therefore, offers a high range of frequency tolerance. 

  • It has a small water absorption, which makes it a good choice to be used in areas where moisture may be the killer of the circuit. Such humid areas require specialized circuits for long-term performance. 

  • The shaping and cutting process of the PCBs created with this substrate is easy and more controllable. 

  • This PCB substrate can bear extreme weather conditions and has a low expansion or contraction rate as compared to the other options; therefore, it is a recommended option by the experts.

  • The design flexibility of the Roger 5880 PCBs is another powerful reason behind their popularity. It is a readily drilled PCB that is easy to route and can be platted without making much effort; therefore, it creates a reliable and easily designed PCB.

  • The basic composition of this material allows it to perform the best even at extreme frequency values.

The following table will help you understand the features in detail:

Characteristic

Value

Test Method

Dielectric Constant (Dk)

2.20 ± 0.02

ASTM D150

Loss Tangent (Df)

0.0009

ASTM D150

Dielectric Strength

> 3.0 kV/mil (> 63 kV/mm)

IPC-TM-650

Volume Resistivity

1 x 10^14 ohm-cm

ASTM D257

Surface Resistivity

5 x 10^14 ohms

ASTM D257

Water Absorption

< 0.02%

IPC-TM-650

Thermal Conductivity

0.20 W/mK

ASTM D843

Coefficient of Thermal Expansion (CTE)

31 ppm/°C (X), 48 ppm/°C (Y), 237 ppm/°C (Z)

ASTM D696

Flexural Strength

27.6 ksi

IPC-TM-650

Hardness

50 Shore D

ASTM D2240

Density

2.2 g/cm³

ASTM D792

Flammability Rating

V-0

UL 94

Here, 

  • "X", "Y", "Z" =  principal axes of the laminate

  • "kV/mil","kV/mm" = equivalent units expressing dielectric strength.

  • "ppm/°C" = parts per million per degree Celsius.

  • "W/mK" = watts per meter per kelvin, a unit of thermal conductivity.

Roger 5880 PCB’s Application

  • The most important and obvious fields where these PCBs are extensively used are those that require tolerance for high frequencies. There is a requirement to choose a strong substrate for the PCBs for long-term use. Some important examples in this regard are:

    • Radar systems

    • Satellite communications

    • Test equipment 

    • Measurement equipment

  • The millimeter wave circuits require the specialized material as a substrate and Rogers 5880 stands the best among other options because of the feature to work in the high frequencies. Therefore, it is widely used in applications like:

    • Antennas

    • Filters

    • Mixers

    • Amplifiers

    • Imaging systems.

  • A wide variety of medical equipment uses Roger 5880 substrate PCBs because of their reliable results. These devices are made with the most reliable and long-life material so that medical experts can get the best results for a long time. Some important devices where Roger 5880 PCBs are used are:

    • MRI machines

    • Ultrasound equipment

    • X-ray machines

Hence, Roger 5880 substrates are one of the most reliable and demanding types of PCBs that are used in multiple fields because of their unique features. They are easy to design, have high moisture and corrosion resistance, and can be implemented in a wide variety of applications. We started with its introduction and worked to get information about its basic characteristics and applications. I hope most of the points are clear now, but if you want to know more about these PCBs, you can ask in the comment section.

Syed Zain Nasir

I am Syed Zain Nasir, the founder of <a href=https://www.TheEngineeringProjects.com/>The Engineering Projects</a> (TEP). I am a programmer since 2009 before that I just search things, make small projects and now I am sharing my knowledge through this platform.I also work as a freelancer and did many projects related to programming and electrical circuitry. <a href=https://plus.google.com/+SyedZainNasir/>My Google Profile+</a>

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Syed Zain Nasir