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The Differences Between Copper PCB and Heavy Copper PCB?

Saturday, October 21st, 2023

With the fast development of digital era, printed circuit board (PCB) has won a huge market in the electronic industry. Nowadays, electronics can be found everywhere, I can say for each electronic products, you will find a PCB or several pcbs are inside. But not every PCB are the same, each printed circuit board plays its unique roles. When it comes to copper pcb, may someone will think about heavy copper pcb, or even think they are the same. But actually, they are totally different, totally from constructure and functions.

What is Copper PCB?

Copper PCB, also known as Copper Core PCB, Copper-based PCB or Copper Clad PCB, which is a type of metal core PCB (MCPCB) that uses copper core as the base substrate. Among all of the PCB types, copper clad pcb is well-known for its extreme high thermal conductivity, which enables to achieve to 401W/m.K, that’s why some people think it is the king of the metal core PCB.

Copper-based PCB consists of three layers: copper foil layer, dielectric layer and base copper layer. Copper foil layer is the electric layer, which is mainly used for components electric connection. Dielectric layer is made by insulation material, so it also called insulation layer. Though it is function as insulation, it has good heat transfer capacity. The base copper layer is the support stone for the whole PCB. Copper core PCB is commonly used in LED lighting and other applications where need good heat dissipation.

What is Heavy Copper PCB?

Heavy copper PCB doesn’t have a clear definition in IPC standard, it is a kind of special PCB just like HDI PCB and extra thin PCB. Generally, for copper thickness equal or exceed 3ounces will be default as heavy copper pcb. For those copper thickness ranges from 20~200ounces is classified as extreme heavy copper PCB.

The base substrate of heavy copper PCB can be FR4 material or aluminum, instead of copper base. This is a significant difference between copper pcb and heavy copper pcb. Heavy copper normally used for a various product but not limited to: high power distribution, bas bur, planar transformers, power convertors, and so on. Due to it enables to carry high current and provide high power, people also called it power supply PCB and high-power PCB.

Differences Between Copper PCB and Heavy Copper PCB?

Except the structural composition, there are still some other differences between the copper core circuit board and heavy copper board. Let’s dive into together.

Copper Thickness

Copper core PCBs typically have thinner copper traces, whereas Heavy Copper PCBs have significantly thicker copper layers. If the trace width is certain, increasing the copper thickness is equivalent to increasing the section area of the circuit, so that it can carry more current.

Current-Carrying Capacity

Copper-based circuit boards are suitable for low to medium current applications. In contrast, Heavy Copper PCBs have thicker copper layers, which enables to handle higher currents without overheating. That’s why it is recommended heavy copper circuit board for high power electronics and high-power applications such as electric car.

Heat Dissipation

Actually, both of them are good in heat dissipation capabilities. But due to the copper clad circuit board is made by copper base, while heavy copper printed circuit board uses epoxy resin or aluminum as the base material, copper core PCB is superior to heavy copper PCB in heat dissipation. So, if your application requires better heat transfer but no need to carry higher power, copper core board is the go-to-choice.

Cost Effective

Among the various metal core PCBs, copper core PCB is the most expensive since the copper core itself is expensive, around 6-7 times than the aluminum core PCB.

Heavy copper PCB also is expensive since it has complex manufacturing processes and thick copper layers. But its price mainly depends on how thick copper thickness it needs. So comprehensive consideration, heavy copper pcb is the most cost-effective.

Applications

Copper PCBs are well-suited for smaller consumer electronics, where cost is a significant factor, and heat generation is minimal.

Heavy Copper PCBs are used in power electronics, automotive applications, and industrial equipment, where high current handling and heat management are essential.

Choosing the Right PCB for Your Project

When choosing between Copper Core PCBs and Power Supply PCBs, consider the following factors:

Your project’s power requirements

Thermal management needs

Budget constraints

Durability and expected lifespan

By evaluating these aspects, you can make an informed decision on which type of PCB is the best fit for your project.

In summary, the choice between Copper PCBs and Heavy Copper PCBs depends on the specific requirements of your electronic project. Copper PCBs are suitable for low to medium current applications with minimal heat generation. On the other hand, Heavy Copper PCBs offer higher current-carrying capacity and superior heat dissipation, making them ideal for high-power applications. Assess your project’s needs carefully to determine which type of PCB will serve you best.

Do you know the relationship between copper thickness and circuit width & spacing?

Saturday, September 2nd, 2023

We know the precision control and performance of a product are paramount, only know that PCB can be built with a nice function, so, to understand the intricate relationship between copper thickness and circuit width and spacing is pivotal. These two parameters are like the gears of a well-oiled machine, interlocking in ways that significantly influence the printed circuit board‘s functionality, signal integrity, and manufacturability. If the designer does not consider the relationship between these two, the design may need to be modified in subsequent production.

In order to avoiding this information, let’s embark on a deeper exploration of this dynamic relationship to uncover its nuances and implications now,

Frist of all, we need to know some basic information about PCB, like copper thickness, circuit width and spacing.

The Essence of Copper Thickness

Copper, known for its exceptional electrical conductivity, is the lifeblood of any PCB. The copper thickness refers to the amount of copper deposited onto the board’s surface during fabrication. It’s the foundation upon which the traces, the intricate pathways that carry electrical signals, are built. The standard copper thickness is often measured in ounces per square foot (oz/ft²) or micrometers (µm). Common options include 1oz (35µm), 2oz (70µm), and even higher, it depends on customer’s requirement.

Circuit Width and Spacing

Circuit width and spacing, though often overlooked, are integral components that determine a PCB’s performance, integrity, and overall functionality. Circuit width refers to the dimension of the conductive traces, while spacing pertains to the distance between these traces. These seemingly simple dimensions have a profound impact on the PCB’s behavior.

Secondly, Unveiling the Intricate Relationship

The relationship between copper thickness, circuit width, and spacing is a sophisticated interplay of electrical properties, heat dissipation, and signal integrity. Let’s delve deeper into this complex web of interactions:

Current-Carrying Capacity and Copper Thickness: Copper thickness directly influences a trace’s ability to carry current without succumbing to overheating. Thicker copper translates to higher current-carrying capacity and reduced resistive losses. However, the trade-off is that wider traces are necessary to accommodate the increased copper thickness.

Resistance and Circuit Width: Wider traces exhibit lower resistance, which in turn reduces voltage drop and enhances the efficiency of signal transmission. Designers must strike a balance between trace width, copper thickness, and available board space.

Spacing and Unwanted Interactions: As circuit spacing decreases, the probability of unwanted interactions, such as crosstalk and electromagnetic interference, rises. Thicker copper can exacerbate these issues due to its larger cross-sectional area. Maintaining appropriate spacing between traces is pivotal to prevent signal degradation and maintain integrity.

Heat Dissipation and Trace Width: Thicker copper also aids in better heat dissipation, a crucial consideration for power-intensive applications. However, this can necessitate wider traces to manage the thermal load effectively.

Signal Integrity and Crosstalk: Smaller spacing reduces the risk of crosstalk, but it’s a double-edged sword. Thicker copper traces may introduce higher capacitance, altering impedance and potentially impacting signal integrity. This delicate balance requires careful consideration during design.

For now, we have known the relationship between them, how to develop a best design between the circuit width & spacing and copper thickness, which depends on what’s you really want, the huge current or heat management? Following details should be considered if you want to develop the best circuit width & spacing.

Current Requirements: Start by understanding the current requirements of your traces based on the components and operational conditions. Selecting the appropriate copper thickness and trace width ensures the PCB can handle the anticipated loads.

Thermal Management: Thicker copper facilitates heat dissipation, which is advantageous for power-dissipating components. However, remember that it might necessitate wider traces to ensure effective heat transfer.

Manufacturability: While thicker copper can enhance current-carrying capacity and heat dissipation, it might pose manufacturing challenges. Consult with PCB manufacturers to align your design choices with their capabilities.

Signal Integrity Analysis: Utilize simulation tools to analyze signal integrity, especially when dealing with smaller spacing and thicker copper. These tools provide insights into impedance matching, potential crosstalk, and overall performance.

Flexibility VS Rigidity: While thicker copper enhances many aspects, it can impact the PCB’s flexibility, crucial for certain applications. Evaluate the mechanical demands of your project and strike the right balance.

Regarding metal core PCB in Best Technology, the copper thickness and its accordingly circuit width & spacing like below, furthermore, it would be better if you can let me know your copper thickness before checking your drawing, we will give you the best solution before formal production.

Copper thickness	Minimum circuit width	Minimum circuit spacing
0.5-2oz	0.25mm	0.23mm
3oz	0.35mm	0.3mm
4oz	0.4mm	0.38mm

(trace_design_guide_of_MCPCB)

Conclusion: Striking the Optimal Balance

The intricate relationship between copper thickness, circuit width, and spacing in PCB design embodies a delicate equilibrium that significantly influences a design’s performance and functionality. This nuanced interplay directly impacts parameters such as current-carrying capacity, resistance, heat dissipation, and signal integrity.

Achieving the optimal balance between these factors requires a deep understanding of electrical properties, thermal considerations, and signal behavior. Designers must carefully evaluate the specific requirements of their projects and leverage simulation tools to fine-tune their choices. Collaboration with PCB manufacturers ensures alignment with manufacturing capabilities.

The dynamic nature of this relationship underscores the constant evolution of PCB technology. As devices become smaller, faster, and more interconnected, the demand for intricate layouts intensifies. Designers must continuously adapt to new challenges, pushing the boundaries of what’s achievable while adhering to the fundamental principles that govern PCB design.

What You Know About Counterbores in PCB Design and Manufacturing

Friday, August 18th, 2023

In the world of design and manufacturing, precision is paramount. Every detail, down to the placement of a single component, can impact the performance and appearance of a product. This is where the concept of counterbores comes into play, a technique employed in various industries to create recessed areas for components or fasteners.

But firstly, what is counterbore? Today we will show you the definition and applications of the countersink in a PCB design.

Definition and Applications:

A counterbore is a cylindrical, flat-bottomed hole that is strategically cut into a material to accommodate specific components or fasteners. It is commonly used in various industries, including woodworking, metalworking, and mechanical engineering. The purpose of a counterbore is to create a recessed area where a component, such as a bolt head, nut, or other hardware, can sit flush with or below the surface of the material. This technique ensures a smooth appearance, prevents interference with other components, and provides mechanical stability.

Counterbores in PCB Design and Manufacturing

In the realm of printed circuit boards (PCBs), counterbores play a crucial role in achieving efficient and functional designs. PCBs are essential components in electronic devices, and their design requires careful consideration of component placement, connectivity, and mechanical stability. Counterbores in PCBs serve several important functions:

Component Alignment and Clearance: Certain components on a PCB, such as connectors, switches, or specialized modules, require precise alignment and clearance for optimal functionality. A counterbore can be introduced to create a recessed area that accommodates these components, ensuring proper alignment with neighboring components and minimizing the risk of interference.

Flush Mounting: To maintain a sleek and compact design, some components need to be mounted flush with the surface of the PCB. A counterbore creates a flat-bottomed recess that allows the component to sit at the same level as the PCB surface, contributing to an aesthetically pleasing and functional layout.

Mechanical Support: Components that are susceptible to mechanical stress or impact may benefit from additional support. By incorporating a counterbore, the PCB design can provide a more secure location for these components, reducing the risk of damage.

Heat Dissipation Enhancement: In applications where certain components generate significant heat, such as power amplifiers or processors, heat sinks are often employed to dissipate the heat. A counterbore can facilitate proper alignment and contact between the heat sink and the component, optimizing heat transfer and overall thermal performance.

The production of counterbores in PCBs involves specialized manufacturing techniques. BEST Technology as a professional PCB manufacturer, we will use precision drilling and routing equipment to create accurately sized and positioned counterbores.

If you want to know more about the counterbores, welcome to follow our post or contact us.

Do You Know How Many Types of Holes in PCB

Tuesday, July 4th, 2023

In the vast realm of engineering and manufacturing, there exists a hidden world of holes, each with its own distinct purpose and position. These holes play a crucial role in facilitating various functions within mechanical and electronic systems. In this blog, we will embark on a journey to explore different types of holes in printed circuit board. So, fasten your seatbelts and let’s delve into the fascinating world of these essential engineering features.

Common Types of Holes in PCB

Upon examining a circuit board, one will discover an array of holes serving specific purposes. These include Via holes, PTH, NPTH, Blind holes, Buried holes, Counterbore holes, Countersunk holes, Location holes, and Fiducial holes. Each hole type fulfills a distinct role and function within the PCB, making it crucial to familiarize oneself with their characteristics to facilitate optimal PCB design.

1. Via holes

Via holes are small openings that connect different layers of a printed circuit board (PCB). They facilitate the seamless flow of signals and power between the layers, enabling efficient circuit design and transmission. Vias can be classified into two types: Plated Through-Holes (PTH) and Non-Plated Through-Holes (NPTH), each serving different functions.

2. PTH (Plated Through-Hole)

Plated Through-Holes (PTH) are vias with conductive material coating the inner walls. PTHs establish electrical connections between different layers of a PCB, allowing the passage of signals and power. They play a crucial role in interconnecting components, facilitating the flow of electrical current, and ensuring the functionality of the circuit.

3. NPTH (Non-Plated Through-Hole)

Non-Plated Through-Holes (NPTH) lack the conductive coating on their inner walls, making them suitable for mechanical purposes only. These holes are used for mechanical support, alignment, or as positioning guides, without establishing any electrical connections. NPTHs provide stability and precision, ensuring proper alignment of components within the circuit board. The mainly different between PTH and NPTH is the copper foil will be plated in the hole wall while NPTH no need to do plate.

4. Blind Holes

Blind holes are partially drilled holes that penetrate only one side of a circuit board. They are primarily employed to connect the outer layer of the board with the inner layer, enabling component mounting on one side while remaining hidden from the other. Blind holes offer versatility and help maximize space in complex circuit board designs.

5. Buried Holes

Buried holes are entirely enclosed within a circuit board, connecting inner layers without extending to the outer layers. These holes are hidden from both sides of the board and serve to establish connections and routes between inner layers. Buried holes allow for denser circuit board designs, reducing the complexity of routing traces and enhancing the overall functionality of the board. They provide a seamless and compact solution without any surface exposure.

6. Counterbore Holes

Counterbore holes are cylindrical recesses created to accommodate the heads of bolts, nuts, or screws. They provide a flat-bottomed cavity that allows the fasteners to sit flush or slightly below the surface of the material. The primary function of counterbore holes is to enhance the aesthetics and functionality of a design by providing a smooth and even appearance. These holes are commonly found in woodworking, metalworking, and engineering applications where a concealed or larger bearing surface is desired.

7. Countersunk Holes

Countersunk holes are conical recesses designed to house the angled heads of screws or fasteners. They are employed to ensure that the screw heads lie flush or slightly below the material surface. Countersunk holes serve both aesthetic and practical purposes, providing a sleek and flawless finish while reducing the risk of snags or protrusions. Their versatility makes them suitable for various applications, from furniture manufacturing to aerospace engineering.

8. Location Holes

Location Holes, also known as Reference Holes or Tooling Holes, serve as key reference points for aligning and positioning components, parts, or fixtures during manufacturing or assembly processes. These holes are strategically placed in a design to ensure precise and consistent alignment, enabling efficient assembly and reducing errors.

9. Fiducial Holes

Fiducial Holes, also referred to as Fiducial Marks or Alignment Marks, are small precision holes or markings placed on a surface or PCB (Printed Circuit Board). These holes serve as visual reference points for vision systems, automated processes, or machine vision cameras.

As we conclude our journey through the fascinating world of holes in engineering, we have gained a deeper understanding of the functions and positions of counterbore holes, countersunk holes, via holes, PTH, NPTH, blind holes, and buried holes. These holes are essential elements in various industries, contributing to the aesthetics, functionality, and efficiency of designs.

After introducing each of them, you should have gained a deeper understanding of their functions, hope this is helpful for you the design holes on your PCB project!!

5 Tips Tell You How to Solder BGA Better in PCBA

Monday, May 29th, 2023

BGA (Ball Grid Array) soldering is a widely used method in the electronics manufacturing industry for mounting integrated circuits onto printed circuit boards (PCBs). This method provides a more compact and reliable connection compared to traditional through-hole or surface mount technology (SMT). However, the complexity of BGA soldering poses various obstacles during the manufacturing process. Herein, we will explore the challenges faced in BGA soldering and discuss effective strategies to address them.

What is BGA Soldering?

BGA soldering is a technique that involves the attachment of integrated circuit packages to a PCB using an array of solder balls. These solder balls are typically made of lead-based or lead-free alloys, depending on environmental regulations and specific requirements. The BGA package consists of a substrate, which acts as a carrier for the integrated circuit, and the solder balls that form the electrical and mechanical connections between the package and the PCB.

The Importance of BGA Soldering in Electronics Manufacturing

BGA soldering plays a critical role in the manufacturing of various electronic devices such as computers, smartphones, and gaming consoles. The increased demand for smaller and more powerful electronics has driven the adoption of BGA packages. Their compact size and high pin density make them suitable for advanced applications where space is limited.

Challenges Faced in BGA Soldering

Component Alignment and Placement

One of the primary challenges in BGA soldering is ensuring accurate component alignment and placement on the PCB. The small size of the solder balls and the dense layout of the BGA package make it difficult to achieve precise positioning. Misalignment during the assembly process can result in solder bridges, open connections, or mechanical stress on the package.

To address this challenge, manufacturers employ advanced technologies such as Automated Optical Inspection (AOI) and X-ray Inspection. AOI systems use cameras and image processing algorithms to verify the correct alignment and placement of BGA components. X-ray inspection, on the other hand, allows manufacturers to see beneath the surface of the PCB and detect any misalignment or defects that may not be visible to the naked eye.

Solder Paste Application

Another significant challenge in BGA soldering is achieving precise and consistent solder paste application. Solder paste, a mixture of solder alloy and flux, is applied to the PCB pads before placing the BGA package. Inadequate or excessive solder paste can lead to solder defects such as insufficient solder joints, solder voids, or solder bridging.

To overcome this challenge, careful attention must be given to stencil design and aperture selection. Stencils with appropriate thickness and properly sized apertures ensure accurate solder paste deposition. Additionally, manufacturers can employ Solder Paste Inspection (SPI) systems to verify the quality and consistency of the solder paste applied. The solder paste that Best Technology uses is SAC305 solder paste, which has good printability and excellent stability.

Temperature Profiling

Temperature profiling, or we can say the thermal management, it is crucial in BGA soldering to ensure proper reflow of the solder paste. The reflow process involves subjecting the PCB to a carefully controlled temperature profile, allowing the solder paste to melt, form a reliable joint, and solidify. Inadequate temperature profiling can lead to insufficient solder wetting, incomplete reflow, or thermal damage to components.

Manufacturers must optimize the reflow oven setup and calibration to achieve the correct temperature profile. Thermal profiling techniques, such as the use of thermocouples and data loggers, help monitor and control the temperature during the reflow process.

Reflow Process

The reflow process itself presents challenges in BGA soldering. The soak zone, ramp rates, and peak temperature must be carefully controlled to prevent thermal stress on the components and ensure proper solder reflow. Inadequate temperature control or improper ramp rates can result in solder defects such as tombstoning, component warpage, or voids in the solder joints.

Manufacturers need to consider the specific requirements of the BGA package and follow recommended reflow profiles provided by component suppliers. Proper cooling after reflow is also essential to prevent thermal shock and ensure the stability of the solder joints.

Inspection and Quality Control

Inspection and quality control are critical aspects of BGA soldering to ensure the reliability and performance of the solder joints. Automated Optical Inspection (AOI) systems and X-ray inspection are commonly used to detect defects such as misalignment, insufficient solder wetting, solder bridging, or voids in the solder joints.

In addition to visual inspection techniques, some manufacturers may perform cross-section analysis, where a sample solder joint is cut and examined under a microscope. This analysis provides valuable information about the quality of the solder joint, such as solder wetting, void formation, or the presence of intermetallic compounds.

In a word, BGA soldering presents unique challenges in electronics manufacturing, primarily related to various factors. By addressing these challenges effectively, manufacturers can ensure the reliability and performance of BGA solder joints, contributing to the production of high-quality electronic devices. Best Technology has rich experience in PCBA assembly and we mounted thousands PCBs for our customers, whatever it is simple design or complex design, all the products are assemble perfect and work well in customer side. Please feel free to contact us for any questions about PCBA.

10 Tips to Reduce the manufacturing cost of Printed Circuit Board

Thursday, March 23rd, 2023

Many times, when PCB engineer or purchaser seek for a PCB manufacturer to make circuit boards, that always think the price is too high, but don’t know where makes the price is so high and how to optimize the cost on the premise of ensuring the quality of the circuit board. Herein, we share a very useful guideline about “Ten tips to reduce the PCB manufacturing cost”, welcome to read on!

Substrate

Different brands of substrate have different price. For a simple example, if you require a multi-layer PCB, Tg should greater than 150^o, and PP need to over 0.20mm, then use GDM will cheaper than KB or SL. But GDM is usually used for making single or double-sided PCB, it is not recommended to make multi-layer circuit board. If you need to fabricate an 8 layers of multi-layer PCB, KB Tg170 is ideal for your choice since it has good performance and relatively cost-efficient.

Solder mask oil

In generally, what we should consider about the solder mask (S/M) are color and brand.

For the solder mask color, the most commonly used are green, white and black, if you would like to choose other special colors such as blue, yellow, gray, the price will be a little more costly.

From the brand aspect, currently the best brand is Taiyo solder mask, because it has high viscosity, stable dielectric constant, good insulation and oxidation resistance properties, but it is more expensive than others. Other brands of solder mask oil will be relatively cheap, but the quality is not particularly stable and can’t be guaranteed. So if the circuit boards need to used on bulk products, we recommend to use Taiyo to get a stable quality.

Printing film

If it is a bulk order with simple design and trace width/space >= 5/5mil, almost manufacturers will use printing film to generate traces. But please remember: the larger the board size, the higher cost of film. (Generally speaking, Prototypes or small orders are use LDI exposure machine to generate the trace, but for mass production, manufacturer will priority choose film and then use LDI.)

Line width/space

The thinner traces, the higher manufacturing price. Because the line is thinner, the accuracy of the equipment and the quality of the chemical solution are required to be relatively high, and the yield will be relatively low, resulting in higher costs. Each manufacturer has its capability, so choose a suitable supplier is most important, view Best’s website to check our capability.

Drill holes

The smaller the hole, the higher the price, the diameter of less than 0.3mm will increase the price. The more holes there are, the higher the price will be. Other special holes will also increase the cost, such as half holes, blind holes, PTH holes larger than 6.0mm, etc. Because the hole is small, only one board can be drilled at a time when drilling the hole on PCB material, which is low efficiency and the possibility of drilling a broken drill bitter is also large, resulting in higher cost.

Finished copper thickness

Finished copper thickness ≥2oz, and hole copper >25μm board will increase the cost. Because the price of copper itself is relatively expensive, the thicker the copper, the higher the price, coupled with the cost of additional electric copper, leads to the overall price rise.

Finished board thickness

There is little difference in the price of PCB with board thickness of 1.2mm and 1.6mm, but if the board thickness is 2.0mm or even thicker, its cost will increase correspondingly. The thicker the board, the more sheets of fiberglass, so the cost will increase accordingly.

Outline

If there are more slots, and the slots are less than 1.0mm, the cost will increase. This is because the gong groove of the board is more shaped, resulting in the processing time is elongated. In addition, if the width of the groove is small, processing can not be too fast, easy to break the milling cutter, so the processing efficiency is low, the natural production cost increases.

Surface treatment

Our common surface treatment processes are: OSP(antioxidant), lead HASL, lead-free HASL (environmental protection), gold plating, immersion gold, ENEPIG and some combination processes. The price of the above process is more expensive in turns, that is, OSP (antioxidant) < lead HASL < lead free HASL < gold plating < immersion gold < ENEPIG.

Tooling fee and testing fee

Tooling fee: in generally most of manufacturers use milling cutter to punch outline if this is a prototype order or small order. But if bulk order, it is needed to use a tooling jig, so there is a tooling fee need to pay.

Testing fee: flying probe tester is usually for small order, mass production need to use testing jig, and there is a different testing fee for both.

Above elements can affect the cost of making a board, you can try to follow those guidelines if you have a limited budget. Or if you want to know a exactly cost, please send RFQ to Best Technology, our sales will give you a best price.

Why Consider Even-Number Multi-Layer PCBs For Your Project?

Tuesday, March 7th, 2023

With the great demands about high-tech electronic equipment, although the single sided PCB or double-sided printed circuit boards have their advantages, multi-layer designs are more beneficial for some applications, that’s why the more and more popular and wide usage of multi-layer PCBs.

Currently in the market and electronic industry, almost of the multi-layer PCB have an even number of layers such as 8, 10 or 12 layers, why designers didn’t consider an odd-number layers? Today let’s explore the reasons together.

Higher cost spent

Normally the standard layers of a multi-layer PCB in the industry are even-numbers, and as the manufacturing technology becomes more and more mature, the cost of fabricating a multi-layer PCB is relative competitive.

But if you want to produce odd-numbers PCB, may the odd-number layers save the cost of material for one layer but the processing cost increase significantly to an even-numbers. Because the core structure requirement for odd layered PCB increases the production cost greatly. However, an even layered PCB can save these costs and reduce the overall manufacturing cost, so why not consider the even number layers?

Long lead time

Long delivery time is unescapable because of the immature fabricating technology. In particular with the odd-layer, the stack up will be unbalance. For example, if it’s an odd layered circuitry, due to the standard symmetrical requirement, the layers will be separated to 2 layers in a one side and another side is 3 layers, so one of the copper layers will be etched away and the odd layered PCB may create uneven weight during the copper plating stage and result in irregular plating issues. This non-standard, odd-layered stack requires an extra core process for layer bonding and adds to the manufacturing time and cost. So, it’s always recommended to use an even number of layers in the PCB stack-up.

Potential quality issue

Quality is very important and crucial for end-application, and the best reason of why not design an odd-number multi-layer PCB is the odd-number layers PCB is very easy to get twist due to the unbalance copper layers. When the PCB is cooled after the multi-layer circuit bonding process, the different lamination tension between the core structure and the foil structure can cause the PCB to bend when cooled. As the board thickness increases, the risk of bending becomes greater for composite PCBs with two different structures. The key to eliminate circuit board bending is to use balanced layering. Although PCBs with a certain degree of bending meet the specification requirements, subsequent processing efficiency will be reduced, resulting in increased costs. Because assembly requires special equipment and technology, the accuracy of component placement is reduced, so the quality will be damaged.

In addition, the twist of an even-number layers PCB can be controlled below 0.7% (IPC 600 standard), but odd layers unable to reach to this quality standard. What’s more, when the warpage of a circuit board greater than 0.7% will seriously affect the operation of Surface Mounted Technology (SMT) process and the reliability of the whole product. Therefore, the designers do not design odd layer generally, even if the odd layer enables to achieve the function, will be designed into false even layer, that is, 5 layers designed into 6 layers, 7 layers designed into 8 layers of board.

Anyway, more layers it is, more complex & difficult the manufacturing will be, and more expensive the cost will be, and the lead time of multi-layer PCB also is different from normal one. So you must choose a right supplier who can provide One-stop service include designing, evaluating, manufacturing or even repairing. Best Technology is an expert in the production of multi-layer PCBs for many companies around the world for over 16 years. Contact us right now and send us inquiries, we are so confident that we can be one of your most reliable suppliers in China.

Do You Know What a Metal Core PCB Is?

Saturday, February 25th, 2023

Metal Core Printed Circuit Board (short for MCPCB) is a technology developed to overcome the thermal limitations of the FR4 Printed Circuit Board. Different with traditional FR4 PCB, the PCB uses FR4 material as base core, while the base material of a metal core PCB is aluminum or copper. So compared with FR4 PCB, Metal Core is a better choice if your boards need to perform in high temperature environment.

What is metal core PCB?

A Metal Core PCB (MCPCB), also known as a thermal PCB or metal backed PCB, is a type of PCB that a metal material as its base for the heating dissipation part of the board. The thick metal is covering one side or double side of the PCB. The purpose of the core of a MCPCB is to redirect heat away from critical board components (such as LED or IC chips), and to less crucial areas such as the metal heatsink backing or metallic core. Base metals in the MCPCB are used as an alternative material to FR4 boards.

Same as FR4 PCB, the metal core PCB can be divided into Single layer MCPCB, Double layers MCPCB and Multi-layer MCPCB.

Single layer MCPCB

A single layer MCPCB is consist of a metal base (usually aluminum or copper alloy), thermal conductivity/dielectric layer and a copper trace layer, you can check below stack up for more details. Due to it only has one layer copper trace, sometimes we called it as one-layer MCPCB or single sided MCPCB.

The single sided MCPCB can be used with surface mount and chip & wire components, and provides much lower thermal resistance than FR4 PCB. What’s more, the metal core provides lower cost than ceramic substrates, and allows much larger areas than ceramic substrates.

Meanwhile, superior heat dissipation and good durability of Aluminum of metal core PCB can greatly eliminate heat sinks or other some voluminous hardware for engineers or designers.

Double layer MCPCB

Double layers MCPCB (2L MCPCB) has two copper layers on one side of PCB, and metal core as a base core on the bottom side of whole MCPCB, so the components only can be populated on the top side, below is a structure of double layer MCPCB.

(Stack_up_of_double_layers_metal_core_PCB)

From the stack up of double layers MCPCB, we can see it consists of a single layer MCPCB and a double sided FR4 PCB, so it needs an additional pressing process to laminate the thermal conductivity and FR4 PCB. Compared with normal FR4, this structure needs more technology and experience on laminating of two layers together with metal core.

There are two layers copper trace on the surface of MCPCB, can we call it as double sided MCPCB like single layer MCPCB?

The answer is NO, because they have different structure and perform different properties. In our next post, we will show you the differences between double sided MCPCB and 2 layers MCPCB.

Multi-layer MCPCB

Same as FR4 PCB, for those copper traces more than 2 layers, we named them Multi-layer MCPCB. Its structure is same as FR4 PCB, but more complex to fabricate. Below is a typical stack up of a 4 layers MCPCB:

Contrast with single layer or double layers MCPCB, multi-layer MCPCB can populate more components and achieve better performance in electronical performance.

Why Choose Metal core PCB?

Metal core PCB offers a great list of advantages when apply in a high-power application, below we listing some benefits of it:

Excellent heat dissipation
Lower thermal expansion than FR4 PCB
Dimensional stability than polyimide FPC
Great durability
Long lifetime
High utilization rate of space due to the heating can be transferred quickly
High strength and lightweight than FR4 PCB
Cost-effective

Where can we use Metal core PCB?

Metal core PCB can be used in high-power filed where requires fast cooling, good heat dissipation characteristics, the following popular applications may give you a guideline:

LED lighting
Power suppliers
Power conversion system
Automotive electronics
Telecom industrial
Photovoltaics
Semiconductors

With more than 16 years manufacturing experience, Best Technology is one of MCPCB supply leaders in Asia with good metal core PCB capability, we are so confident that we can provide you high quality, fast delivery and excellent one-stop service. Warm welcome to contact us if you have inquiries.

How to choose surface finish on Printed Circuit Board？

Saturday, December 17th, 2022

When finish the PCB design, we should choose a suitable surface finish to protect traces from corrosion. Nowadays, the most popular surface treatments for PCB manufacturer to use are HASL/LF HASL, OSP and ENIG.

Different surface treatment has its unique functionality and the cost also is different. This article we will show you the pros and cons of the three surface finishing which use while the PCB manufacturing process.

HASL Surface Finish

HASL (Hot Air Solder Level) can be known as tin-lead HASL and lead-free HASL, it was the mainstream surface treatment technology in the 1980s, but with the increased of “small and high density” demands in PCB, there are less and less circuit boards use the HASL technology because it will cause the defective products due to the solder point are easy to leave on the board surface during SMT process. In view of this situation, some PCB board manufacturers or designers prefer use OSP or immersion gold to ensure the good quality products as well as smooth production process.

Tin-lead HASL

Advantages:

1） Economical and widely available.

2） Excellent solderability.

3）Better mechanical strength & lustrousness than lead-free HSAL.

Disadvantages: it is harmful to environment and violates RoHS compliance.

Lead-free HASL

Advantages: low cost, good solder performance and environmental.

Disadvantages: mechanical strength & lustrousness are not good than lead HASL.

In additional, due to the poor surface flatness of HASL circuit boards, neither leaded nor lead-free HASL is not suitable for soldering fine-pitch components or plated through-holes, because it will cause the short circuits and poor welding during the assembly process.

OSP

OSP (Organic Solderability Preservatives) also named as pre flux, the working principle is to generate a layer of organic film chemically on the copper surface to protect the surface from oxidation or vulcanization in the room environment. Meanwhile, OSP also can increase the oxidation resistance, heat shock resistance and moisture resistance of a PCB.

OSP is equivalent to an anti-oxidation treatment, the protective thin film can be easily removed by the flux quickly under the high soldering temperature, then it makes the exposed copper surface immediately combined with the molten solder in a very short time to become a solid solder spot.

At present, the usage of OSP surface finishing process has increased significantly because it is appropriated for both low and high-end products. If your application has no surface connection functional requirements or storage life limitations, the OSP process is the most desirable surface treatment process.

Advantage:

1）With all the advantages of bare copper soldering, expired (more than 3 months) boards can also be resurfaced, but one time is better.

2）Good for fine-pitch, BGA and smaller components.

3）Low cost and easy to rework.

4）Simple process and easy to ensure quality.

Disadvantage:

1）OSP is easily affected by acid and humidity, so must be packed with vacuum.

2）Need to do surface treatment again if storage time more than 3 months.

3）It should be used within 24 hours after unpacking.

4）OSP is an insulating layer, so the test point must be printed with solder paste to remove the original OSP layer for electrical testing.

ENIG

ENIG (Electroless Nickel/Immersion Gold) is one of a chemical nickel gold deposition method, the working principle is to generate a layer of coating by chemical REDOX reaction to get a thicker gold layer. Currently, ENIG is mainly used in the surface of the circuit board with connection functional requirements and long storage life.

Advantage:

1）Can be stored long time as well as no oxidation.

2）Good flatness surface and suitable for small solder point components.

3）Good solderability.

4）Can be used as the base material for COB wire bonding.

Disadvantage:

1）High cost than other two surface treatments.

2）Easy to exist black-pad issue during production process.

As we can know from above information, each PCB surface treatment has its own merit and demerit, you can choose the one according to the effect you want to reach, as well as your cost.

If you don’t know which is best for you, you can send inquiry to us, our professional engineering team and PCB sales will choose the suitable one for you. Welcome to contact us if you have any other questions.

What is RF PCB board?

Tuesday, November 23rd, 2021

You may have ever heard of RF PCB, but do you know What it is and What are the characteristics of these kinds PCB?

Today let us make a simple introduction for it.

RF PCB, means radio frequency PCB. People also called these PCB High frequency PCB, it is for the PCB with a higher electromagnetic frequency, and it is used on the products field with high frequency. (Frequency greater than 300MHZ or wavelength less than 1 meter) and microwave (frequency greater than 3GHZ or wavelength less than 0.1 meter). It is made by microwave substrate with common PCB manufacturing process or with some special way to make.

High-frequency boards have very high requirements for various physical properties, accuracy, and technical parameters, and are often used in communication systems, automobile anti-collision systems, satellite systems, radio systems and other fields.

How can we know which PCB materials are suitable for making the RF boards?

When evaluating the high-frequency characteristics of a substrate material, the key to its investigation is the change in its DF value (Dissipation Factor).

For substrate materials with high-speed and high-frequency characteristics, in terms of changing characteristics at high frequencies, there are two distinct types of general substrate materials: one is that with the change of frequency, its (DF) value changes very little. There is another type that is similar to the general substrate material in the range of change, but its own (DF) value is lower.

The common epoxy resin-glass fiber cloth-based materials (FR4), the DK value at the frequency of 1MHz is 4.7 and the change of the DK value at the frequency of 1GHz is 4.19. Above 1GHz, the change trend of its DK value is gentle. The change trend is that as the frequency increases, it becomes smaller (but the change is not large). For example, at 10GHz, the DK value of FR-4 is generally 4.15. The substrate material with high-speed and high-frequency characteristics changes in frequency. When the DK value changes slightly, the DK value keeps changing in the range of 0.02 when the frequency changes from 1MHz to 1GHz. Its DK value tends to decrease slightly under different frequency conditions from low to high.

On the other hand, the thermal expansion coefficient of the high-frequency circuit board substrate and the copper foil must be the same. If they are inconsistent, it will cause the copper foil to separate during the cold and hot changes. Secondly, in a humid environment, the water absorption rate must be low, and high water absorption rate will cause dielectric constant and dielectric loss when wet. In general, the heat resistance, chemical resistance, impact resistance, and peel resistance of the high-frequency sheet must be good.

The following are several commonly used high-frequency and high-speed PCB boards we have summarized:

Rogers: RO4003, RO3003, RO4350, RO5880, etc.

TUC: Tuc862, 872SLK, 883, 933, etc.

Panasonic: Megtron4, Megtron6, etc.

Isola: FR408HR, IS620, IS680, etc.

Nelco: N4000-13, N4000-13EPSI, etc.

Other materials like Arlon, Teflon, Taconic are also good for the manufacturing of RF PCB boards.

If you have any question for RF pcb, welcome to send your request and question to discuss more.

PCB & MCPCB – Best Technology

Archive for the ‘FR4 PCB’ Category

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