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What Is the Importance of Ground Plane in PCB EMC Design?

Saturday, March 30th, 2024

In the design of electronic products, electromagnetic compatibility (EMC) is a crucial consideration. Particularly in the design of printed circuit boards (PCBs), the rationality of EMC design directly impacts the performance and stability of the product. Among the many factors affecting EMC, one factor is especially critical, and that is the design of the ground plane. Today, let’s talk about the impact of grounding on EMC.

In an electronic product, grounding is a very important element, it is directly related to EMC compliance. Especially in large equipment, the grounding of multiple systems and subsystems is involved. It can be said, a good grounding system means the half successfully of a product.

What are Ground Plane and EMC in a PCB?

The ground plane, as the reference potential in a circuit, not only carries the return path of current but also plays a role in electromagnetic shielding and noise suppression. In high-frequency circuits, the impedance and layout of the ground plane have a significant impact on signal integrity. Unreasonable ground plane design may result in signal interference, increased radiation, and decreased system stability.

EMC stands for Electromagnetic Compatibility. It refers to the ability of electronic devices and systems to operate properly in their intended electromagnetic environment without causing or experiencing interference. EMC ensures that devices can function without adversely affecting other devices nearby or being affected by electromagnetic interference from external sources. Generally, the ground planes will showing three shapes, please see as following:

Why A Grounding Must be Designed in PCB?

Grounding can be understood as an equipotential point or plane serving as the reference potential for a circuit or system, which can be a specific ground layer in a PCB or the metal chassis of a product. While many perceive the purpose of designing a ground plane primarily to prevent external electromagnetic interference (EMI), but in printed circuit board design, it serves multiple purposes beyond this.

Generally, a well-designed ground provides a common reference zero potential for all circuit units within a system, ensuring no potential difference between circuits and thus stable operation. It also protects circuits from damage, ensuring the safe functioning of electronic products. For instance, ground can provide discharge paths for transient disturbances and dissipate accumulated charges on product metal enclosures induced by static electricity, to prevent potential sparks that may cause interference internally. Additionally, choosing appropriate grounding for shielding structures can yield effective electromagnetic shielding.

Grounding design is very necessary especially for medical industry. As we know, there are many medical devices are directly connected to patients’ bodies, such as monitors. In cases where the chassis carries voltage due to poor grounding, fatal risks may arise. Furthermore, grounding reduces common-mode interference currents flowing through PCBs and prevents high-frequency EMI signals within products from reaching equivalent radiating antennas. Thus, grounding is typically a primary method for noise suppression and interference prevention.

Design Principles of Ground Plane in PCB

A well-designed grounding system should not only consider the radiation and conduction of individual PCBs but also prevent from a systemic perspective. In the design phase, failure to carefully consider the grounding system may indicate a high likelihood of EMC failure for the system. So, knowing the design principles is extremely important to make sure the successful of EMC.

  • Keep it short and wide

To reduce the impedance of circuits, especially in high-frequency circuits, the ground plane should be made as short and wide as possible. This helps to minimize the return path of the current, thereby reducing EMI.

  • Partition layout

For complex PCB designs like multilayer PCBs, it is recommended to use a partition layout to separate the ground planes of different functional modules. This helps to isolate noise interference between different modules.

  • Single-point ground and multipoint ground

Depending on the circuit’s operating frequency and signal characteristics, choose between single-point grounding or multipoint grounding. Single-point grounding is suitable for low-frequency circuits, while multipoint grounding is more suitable for high-frequency circuits.

PCB_ground_plane_design
  • Ground plane

Where possible, use a ground plane as the ground. The ground plane can provide a low-impedance return path and aid in electromagnetic shielding.

How to Optimize Your Grounding Design?

As for PCB that has already design the circuit layout, how to optimize the ground to get the maximum EMI? Here are some tips that may helpful for you.

  • Fill the blank areas of the PCB with ground planes to increase the ground plane’s area and reduce impedance.
  • Reducing the area of ground loops helps to decrease electromagnetic radiation and induced noise.
  • Power lines and ground planes should be placed as close as possible and run parallel to reduce the area of the current loop.
  • Placing decoupling capacitors between power and ground planes helps to filter out high-frequency noise.
Semi_flexible_pcb

In PCB EMC design, ground plane design is an essential step that cannot be ignored. By following the principles and optimization methods of ground plane design, the EMC and signal integrity of electronic products can be significantly improved. Therefore, in PCB design, sufficient attention and consideration must be given to ground plane design. Welcome to contact Best Technology if you want to know more about ground and EMC design.

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2024 Newest Guide to High Thermal Conductivity PCBs

Monday, March 18th, 2024

Currently, with the rapid development of the digital era, the demands and requirements for electronics have increased significantly. Many double-sided and multi-layer boards have high density and power, making it difficult to dissipate heat efficiently. Conventional printed circuit board substrates such as FR4 and CEM3 are poor thermal conductors with interlayer insulation, the heat can’t transfer out, which leading to high-temperature failure of electronic components and devices. So, engineers and researchers are aiming to find high thermal conductivity PCBs to solve such problems, and metal core PCB and ceramic PCB stand out at this time.

Metal core PCB is a type of PCB that made by metal alloy material as the base core, commonly are aluminum core or copper core, rarely is iron PCB. They are popular because of its good heat dissipation properties and good mechanical strength.

What is Aluminum PCB and Why Use It?

Aluminum substrate is a low-alloyed Al-Mg-Si series high-ductility alloy sheet. It exhibits excellent thermal conductivity, electrical insulation properties, and mechanical machinability. Compared to traditional FR-4, with the same thickness and line width, aluminum substrate can carry higher currents, withstanding voltages up to 4500V. Its thermal conductivity coefficient exceeds 2.0.

A normal single side (1L) aluminum core PCB consists of three layers, aluminum base, dielectric layer and copper trace layer. Generally speaking, 1L aluminum PCB is always used for LED lighting, high current LED, spotlight, etc. So it also called LED PCB. For high-end applications, there are also designs for double-sided boards, structured as circuit layer, insulation layer, aluminum base, insulation layer, and circuit layer. In rare cases, multi-layer boards are used, which can be composed of multi-layer FR4 boards laminated to insulation layers and aluminum base.

Aluminum_PCB

The thermal conductivity of aluminum core is range from 1-3W/m.k, the higher conductivity, the better heat dissipation. However, not all the projects is suitable for higher conductivity, it should depend on the specific requirements, such as mechanical strengthen, corrosivity. Nowadays, Best Technology used 6061, 5052, 1060 aluminum alloy as the metal core, others also available if customers have requirements.

How Does Copper Core PCB Works?

Copper substrate is the most expensive type among metal substrates, offering significantly better thermal conductivity compared to aluminum and iron substrates. It is suitable for high-frequency circuits, regions with large temperature variations, and precision communication equipment for heat dissipation purposes, as well as in the construction and decoration industries.

The copper PCB’s circuit layer requires a significant current-carrying capacity, thus necessitating the use of thicker copper foils, typically ranging from 35μm to 280μm in thickness. The thermal insulation layer is the core technology of the copper substrate, composed of aluminum oxide and silicon powder as the main thermal conductive components, filled with a polymer of epoxy resin. It exhibits low thermal resistance (0.15), excellent viscoelastic properties, and possesses the ability to resist thermal aging, withstanding mechanical and thermal stresses.

The metal base layer of the copper substrate serves as its supporting component, requiring high thermal conductivity. It is typically made of copper foil, though copper plate can also be used (with copper PCB offering better thermal conductivity, around 1-400W/m.k). These substrates are suitable for conventional mechanical processing methods such as drilling, punching, and cutting.

Copper_core_PCB

What Are Differences Between Copper and Aluminum PCB?

Though both copper and aluminum are metal core PCB, they still have some differences in characteristic and manufacturing. Knowing their differentiation can help you to understanding and making correct decision in material selection.

  • Material

Copper has excellent electrical conductivity and mechanical strength, so copper PCB is well-suit for high frequency circuits and high-power electronic equipment. While aluminum is slightly inferior to the copper base, so it is a good choice of low-power devices.

  • Cost

Compared with copper, aluminum PCB has much advantages in cost, so if you have limited budget and require to use for low-power equipment such as LED lights, aluminum is the better one.

  • Manufacturing

Due to copper has great hardness and good strengthen, it requires for special technical and complex processes, for example: chemical etching, electro-plating. However, the lightweight of aluminum makes it easy in manufacturing. In addition, PTH (plated through holes) can be created on copper PCBs, but not on aluminum ones.

  • Physical Property

The difference in elastic modulus between copper and aluminum is significant, resulting in less warping and expansion/contraction in copper substrates compared to aluminum substrates.

  • Application

Aluminum PCB is lighter than copper substrate, the material cost is lower, often used in daily LED lights or electronic equipment. Because of its strong thermal conductivity and better electrical conductivity, copper substrate is usually used in high-speed circuits and high energy circuits. In addition, copper substrates are also widely used in areas requiring high heat transfer and heat dissipation performance, such as power amplifiers, power supplies, power tools, automotive engine controllers and solar inverters.

Sink_Pad_PCB

What is Ceramic PCB? And Its Thermal Conductivity?

Ceramic PCB is one of the high thermal conductivity PCBs in this industry. They have good high-frequency properties and electrical properties, and have high thermal conductivity, chemical stability and excellent thermal stability of organic substrates without. It is a new generation of large-scale integrated circuits and power electronics module ideal packaging materials. The thermal conductivity of the ceramic substrate can reach about 220W/ M.K according to the preparation method and the material formula. Theoretically speaking, the thermal conductivity of ceramic circuit made by alumina is 24-28W/m.k, AlN is 150-240W/m.k and for BeO is 22-250W/m.k.

Ceramic PCB can be divided into various types of PCB according to its different PCB manufacturing process, they are thick film, thin film PCB, DPC, DBC, HTCC and LTCC ceramic circuit board. Different types of PCB made in different temperature and uses different materials, this means they have different chemistry and physical properties. So you should take them into consideration when designing a ceramic PCB for your device.

Ceramic_PCB

A Reliable PCB Supplier in China – Best Technology

Whatever you choose metal core PCB or ceramic PCB, a reliable supplier is necessary and needed. Best Technology has extensive manufacturing experience in PCB and we are very confident that we can serve you the best service and high-quality product. With rich experience and strong R&D team, we know how to provide you the best solution and evaluate the design files for you. We have professional DFM (Design For Manufacturing) process to identify the mistakes or inappropriate layout in design. Welcome to contact with us to discuss your PCB projects.

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Top 1 Design and Manufacturing Considerations for Bendable Aluminum PCBs

Thursday, March 7th, 2024

You know, bendable aluminum PCBs have gained prominence in various electronic applications due to their unique ability to flex and conform to curved surfaces. Unlike traditional rigid PCBs that are commonly composed of materials like fiberglass , these PCBs utilize aluminum as the base material, allowing it bendable and flexibility when needed. Compared to the rigid characteristics of traditional metal core PCB, bending aluminum PCB can be adapted to specific space requirements and shape requirements. In this article, we will introduce the characteristics of bendable aluminum PCBs and explore the key considerations that engineers and manufacturers need to pay attention during the design and production process.

What Are the Benefits of Bendable Aluminum PCBs?

May some designers are reraly to know the bendable aluminum PCB, in their congnition, the bendable PCBs are including flex circuits, rigid flexible circuit and FFC, and aluminum PCB is classfied into one of rigid PCB. But here, Best Technology is so proud to say, we have developed bendable aluminum PCB and we can manufacture it with fast delivery and high-quality, this is what we prouded.

The primary advantage of bendable aluminum PCBs is their flexibility. They can be bent and shaped to fit into various form factors and designs, making them suitable for applications where space is limited or where flexibility is required and traditional rigid boards are not ideal. Common applications include wearable devices, curved displays, and other electronic systems with unconventional form factors.

Additionally, bendable aluminum PCB has the advantages of aluminum, so it has good heat dissipation and higher thermal management than traditional PCBs. This feature is crucial for maintaining the reliability and performance of electronic devices, especially those operating in high-temperature environments.

Considerations During the Design Process

Al Material Selection:

Considering that it is a bendable aluminum substrate, it must be satisfied that the material selection should be bendable but at the same time have good heat dissipation of the metal base. This aluminum base material is a specially designed aluminum alloy or aluminum base composite material. Meanwhile, the thickness of the material is critical, such as the material is generally from 0.2mm to 1.6mm, of which 0.2mm to 1.0mm is the more common bending metal substrate thickness.

Flexibility Requirements:

Defining the flexibility requirements is a crucial step in the design process. The degree of bending, bending radius, and any other factors related to flexibility must be clearly defined based on the intended application. For instance, a wearable fitness tracker might require a specific bending profile to comfortably conform to the curvature of the wrist.

Also note that the bending radius is different for materials of different thicknesses. In general, a smaller bending radius usually corresponds to a thinner board material, while a larger bending radius can accommodate a thicker board material.

Circuit Layout:

The layout of the circuit components plays a pivotal role in ensuring the longevity of bendable aluminum PCBs. Designers should strategically plan the arrangement of components to accommodate bending without subjecting critical elements, such as sensors or microcontrollers, to excessive stress. Even distribution of components contributes to a balanced bending profile.

And the pad should not be designed at the bend of the bending, which will cause damage to the assembly components after bending, or even no way to bend. In addition, the welding pad near the bending cross should also be kept away from the bending line to avoid collision and extrusion of the components after bending.

Bending Radius:

Determining the minimum bending radius that the PCB can tolerate is essential for preventing structural damage or compromise in electrical performance. Specific bending radii should be defined based on the application’s needs. For example, a bendable aluminum PCB designed for a wearable device might need to withstand repeated bending with a predefined radius.

Dielectric Layer:

Choosing an appropriate dielectric material is crucial for maintaining insulation between different layers of the PCB. The dielectric layer should possess flexibility to withstand bending without compromising its insulating properties.

As we know, when design the aluminum PCB, the thermal conductivity is also important. Bendable aluminum also has the thermal conductivity requirement, but when the thermal conductivity material is higher, the higher the content of ceramic powder in material. And when the content of ceramic powder is higher, the brittleness of the material is higher, and it is easier to break or break after bending. The material of 1W/m.k is more bendable than 3W/m.k。

(Bendable_MCPCB)

Considerations During the Manufacturing Process

Bendable aera line:

For the production requirements of the light plate, the V-cut mark is generally used to determine the complete line at the bend, and attention should be paid to the depth control of the v-cut, so as not to damage the line.

Testing and Validation:

Prototyping is a vital phase in the manufacturing process of bendable aluminum PCBs. Thorough testing and validation are necessary to ensure that the PCB meets the required electrical and mechanical specifications. Bending tests simulating the intended application conditions should be performed to assess the PCB’s durability. such as bending test, bending angle test.

Generally speaking, after the bare board finished, it’s not bendable to the required angle. In order to avoid bad transportation or collision, some customers require not to bend and they will bend it by themselves. But if the customers don’t want to bend the board by himself, we also can help to bend it, it will require mold and it need to custom the package for shipping. The custom package can help to protect the damage in shipping.

Collaboration with Manufacturers:

Close collaboration with experienced PCB manufacturers is key to successful production. Manufacturers with expertise in flexible PCB fabrication can provide valuable insights into the manufacturing process. Working together ensures that the design aligns with manufacturing capabilities, optimizing the production of bendable aluminum PCBs.

Conclusion

In a word, the design and manufacturing of bendable aluminum PCBs involve a series of critical considerations to ensure the success and reliability of the final product. From material selection and flexibility requirements to testing, validation, and compliance with industry standards, each step plays a pivotal role in creating PCBs that meet the unique demands of modern electronic applications. By carefully addressing these considerations, designers and manufacturers can unlock the full potential of bendable aluminum PCBs in diverse and innovative electronic devices. Welcome to contact Best Technology if you want to know more.

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How Does the Ceramic PCB Works in IGBT Modules?

Friday, January 19th, 2024

IGBT (Insulated Gate Bipolar Transistor) is a bipolar junction transistor (BJT) with a MOS gate, or we can say that an IGBT module is a combination of BJT and MOS module. Despite its small size, the IGBT chip can control the transmission of electrical energy. It can switch the current 100,000 times within 1 second under an ultra-high voltage of 650 million volts.

What is the Working Principle of IGBT?

IGBT combines the features of a transistor and a switching circuit, making it a new type of electronic component that can control current efficiency. Its structure allows it to achieve current control from turn on to off without generating excessive leakage current, as well as not affecting the operation of other circuits.

The working principle of IGBT modules including two parts – the current control of MOS gate and BJT transistor. When the voltage of MOS gate changes, it affects the conduction of the transistor, thus controlling the flow of current. When the BJT comes into play, it controls the flow of current, so that improve the working efficiency of the IGBT.

(Working_principle_of_IGBT)

How Does A Ceramic PCB Protect IGBT Modules from Overheat?

As you know, IGBT modules have been applied for many years in various industries such as automotive, industrial, aerospace, consumer electronics, and more. However, optimizing the thermal dissipation of IGBT packaging is crucial to enable the modules to operate at higher power conditions. If heat dissipation is improved, IGBT modules can be used in more advanced applications.

You might be wondering how much heat does an IGBT module generate during running? It’s equivalent to the heat produced by 100 electric furnaces. This substantial amount of heat must be dissipated immediately from the IGBT chip, that’s why the ceramic circuit board stands out.

(Ceramic_pcb_with_DPC_technology)

In IGBT modules, ceramic PCBs are placed beneath the IGBT chip, or we can say the chip is assembled on the ceramic circuit board. The ceramic PCB connects and supports the chip, rapidly dissipating heat to the outer package. This method protects the chip from the adverse effects of heat.

Why ceramic PCBs Are Suitable for IGBT thermal dissipation?

Ceramic materials exhibit excellent thermal dissipation and electrical insulation properties. Unlike aluminum metal core PCBs, ceramic PCBs do not use insulation layers that hinder heat dissipation. In the manufacturing process of ceramic PCBs, copper foil is directly bonded to the ceramic substrate under high pressure and temperature (it depends on the different technology and different copper thickness). During PCB manufacturing, IGBT and other components are mounted on the circuit board through assembly technology.

Ceramic materials have extremely high insulation capabilities, enduring breakdown voltages up to 20KV/mm. At present, there are three ceramic materials that can be used for IGBT modules, they are 99% or 96% Alumina (Al₂O₃), Aluminum Nitride (AlN), and Silicon Nitride (Si₃N₄).

The thermal conductivity of alumina PCB is 15-35W/mK, aluminum nitride PCB is 170-230W/mK, and silicon nitride PCB is 80+W/mK. In contrast, aluminum core circuit boards only have a thermal conductivity of 1-12W/mK.

Applications of Ceramic PCBs in IGBT Packaging

Alumina PCBs are the most commonly used circuit boards in IGBT modules due to their lower cost. But if IGBT modules have higher power or precision requirements, AlN ceramic PCBs and Si3N4 PCBs are the most suitable choices. Because they have higher thermal dissipation and thermal expansion coefficients (CTE) close to semiconductors. Since different ceramic substrate has different features, the uses of ceramic PCB should depend on the specific requirements of IGBT modules.

In addition, with the development of Silicon Carbide (SiC) and Gallium Nitride (GaN) materials, they are starting to be used for IGBT chips due to their high-frequency, high-power, and high-temperature characteristics. Maybe in the future, aluminum nitride PCBs and silicon carbide PCBs will be increasingly applied to high-power IGBT modules in high-density three-dimensional packaging.

Common Properties of Using Ceramic Circuit Board

  • Excellent thermal conductivity and voltage resistance of ceramic substrates.
  • Copper trace layers has extremely high current-carrying capacity.
  • Strong adhesion and reliability between circuit layers and ceramic substrates.
  • Good soldering performance, suitable for wire bonding.
(Ceramic_PCB)

How to Solve the Overheat Issues in IGBT?

Though the ceramic PCB is good at heat dissipation, there still some overheat occasions happened if small power or long-time operation. Here we summarized some solutions for such issues.

1. Clean the heat sink to ensure tight contact between the IGBT and the heat sink.

2. Clean the fan, including the fan blades and lubricate the bearings if needed.

3. Clear the airflow path of the fan.

4. Replace with higher power IGBTs, ensuring the withstand voltage is not lower than the original IGBT’s value.

Above all are the information that we’d shared, welcome to contact us if you want to know more. Best Technology is a historic company which has over 17 years PCB manufacturing experience, here you can enjoy the one-stop ODM & OEM service, one-to-one after sales, quick delivery and high-quality products.

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What Are Differences of ENIG VS ENEPIG in PCB Manufacturing – Series 2

Tuesday, January 2nd, 2024

In our last blog, we simply introduced ENIG surface treatment in PCB manufacturing, and this time, we will share more information about the comparison of ENIG and ENEPIG.

What is ENEPIG Surface Treatment?

ENEPIG stands for Electroless Nickel Electroless Palladium Immersion Gold. This type of metal coating on the PCB pad surface consists of three layers—nickel, palladium, and gold. Apart from protecting the copper surface from corrosion and oxidation, the ENEPIG surface treatment is also suitable for high-density SMT (Surface Mount Technology) designs.

For its manufacturing process, manufacturers begin by activating the copper surface, followed by depositing a layer of electroless nickel, then a layer of electroless palladium, and finally, a layer of immersion gold. The process is somewhat similar to the one they follow in the ENIG process, but adding a palladium layer to the ENIG technology. The palladium layer not only improves the surface protection of the PCB, but also prevents nickel from deteriorating and inhibits interactions with the gold layer.

Pros of ENEPIG Surface Treatment

  • Reduce the black pad issues
  • Excellent solderability and high reflow soldering performance
  • Provide high-reliable wire bonding capability
  • High-density design available
  • Meet the miniaturization standards
  • Suitable for extra thin PCBs

Cons of ENEPIG Surface Treatment

  • Expensive than ENIG process
  • Thicker palladium layer will decrease the effective of SMT soldering
  • Longer wettability time

What are the Differences Between ENIG and ENEPIG?

The main difference between ENIG and ENEPIG is the palladium layer. This is the extra layer that added in ENEPIG process, which provides high oxidation resistance, enhance the electrical performance of the surface cleanliness and improve the abrasion resistance of the PCB surface. However, the palladium layer also increases the cost of manufacturing.

Additionally, the inconsistent surface cleanliness of ENIG, resulting from low solder joint reliability, particularly in gold wire bonding, is a concern. Extra procedures are also required to prevent nickel corrosion in ENIG. When considering it into manufacturing, the ENIG is well-suited for lower-end electronic products.

(ENIG_VS_ENEPIG)

The Considerations of Selecting ENIG or ENEPIG Surface Finishing

Though both two surface treatments offer excellent electrical performance and heat dissipation properties, there are still some conditions that need to consider when choose them.

  • Budget

Cost is an important factor when choose a suitable surface treatment. As we explain above, ENEPIG is expensive than ENIG, if you are trying to find a relative cost-effective coating, then ENIG is the best choice.

  • End-applications

The end-applications or finished products also determined the selection of surface finishing. For example, if your PCB will be used in high temperature applications, ENIG would be the better one since it can withstand high temperature.

  • Flatness

Many traditional surface finishes have poor flatness and smoothness, this brings the big challenge of small-size components mounted. Especially for those fine-pitch components like BGA, an uneven surface can result many problems. However, both ENIG and ENEPIG offer highly smooth surface finishes, forming thin and uniform layers on the solder pads.

  • Bonding demand

ENEPIG provides the optimal choice for wire bonding due to its highly smooth surface finish, which enhances wire bonding capabilities.

  • Environment-friendly

Some traditional surface treatments contain hazardous substances, making them non-compliant with RoHS requirements. Both ENIG and ENEPIG made by Best Technology are fully RoHS compliant and lead-free, so you are don’t worry about the environment unfriendly.

At the end, the choice between ENIG and ENEPIG surface treatments in PCB manufacturing involves a careful consideration of various factors. While both options offer excellent electrical performance, heat dissipation properties, and compliance with environmental standards like RoHS, specific project requirements and priorities will guide the decision-making process. If you are still confuse about the selection of surface treatment, welcome to contact with us, Best Team will give you a best solution that can meet your specific demands and save money for you.

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Why Thermal Conductivity Layer is Important in Aluminum PCB?

Tuesday, January 2nd, 2024

In the aluminum PCB design, people always mention the thermal conductivity value. Do you know what about thermal conductivity and you know what is the role of this layer in the aluminum core circuit board? Welcome to keep reading if you are interested in it.

(1_layer_aluminum_pcb)

What is thermal conductivity?

Thermal conductivity is a physical value signifies the capacity of a material to allow heat flow per unit area through it in a unit of time. A higher thermal conductivity indicates better heat conduction for the material. In the field of heat generation and thermal management products, thermal conductivity is a crucial parameter as it relates to the product’s heat dissipation capability and stability. In the structure of aluminum, the thermal conductivity layer is always stand between the copper circuit layer and base material, so that the heat generated by product can be transfer quickly to outside.

(Stack_up_for_1_layer_aluminum_PCB)

Significance of Thermal Conductivity in Aluminum PCBs

Aluminum substrates are commonly used materials in heat dissipation and thermal management products. Their thermal conductivity is a vital element evaluated heat dissipation properties typically in W/m·K. It can be understood as the material’s heat transfer rate, i.e., the amount of heat conducted per unit time. Specifically, assuming the same amount of heat is conducted in aluminum substrates and other materials, the conduction rate of aluminum substrate will be faster over a certain period. This implies that aluminum substrates can transfer heat more quickly from the heat source to the external environment, achieving efficient heat dissipation.

Impact of Thermal Conductivity on Heat Dissipation Products

The primary function of thermal management products is to dissipate heat. How does thermal conductivity specifically affect them? Let us dive into from below aspects:

1. Thermal Conductivity Value

A higher thermal conductivity leads to better heat dissipation capability, as it can achieve faster transfer of heat from the heat source to the environment. Therefore, thermal conductivity of aluminum substrates plays a crucial role in the heat dissipation products, such as the LED lights, industrial power devices, automotives. At Best Technology, the thermal conductivity we used for aluminum PCB always is range from 1.0 to 3.0W (thickness=75-200um). Different thermal conductivity value has its own thickness.

2. Product Stability

The stability of a product also depends on its thermal conductivity. According to our 17+ manufacturing experience, insufficient thermal conductivity in heat dissipation products may result in overheating during prolonged operation, potentially shortening the product’s lifespan. Let me take a simple example, assume your mobile phone is under long time playing games, then it will generate many heats, finally causing the overheating phenomenon. And this will shorten its lifecycle if you always do like that.

(Single_sided_4_layer_aluminum_PCB)

When it comes to thermal conductivity selection, there is a big misunderstanding is that some may believe that higher thermal conductivity in aluminum substrates is always better. However, this is not entirely accurate. While higher thermal conductivity is generally favorable, it does not mean that aluminum substrates with the highest thermal conductivity are suitable for all heat dissipation applications. In specific use cases, it is essential to choose the appropriate thermal conductivity for aluminum substrates based on actual requirements to achieve the optimal heat dissipation effect.

By the way, if you want to choose higher thermal conductivity value, ceramic PCB is a better choice, which can achieve 24W or more. It mainly depends on its ceramic substrate material, like the Al2O3 thermal conductivity value is around 24W~28W/m-K, while AlN enable to reach 150W~240W/m-K.

Conclusion

All in all, to ensure optimal heat dissipation effects and stability, it is crucial to choose the right thermal conductivity for aluminum substrates based on actual needs. The careful consideration of thermal conductivity values in aluminum PCBs is integral to the longevity and performance of heat dissipation products, emphasizing the importance of informed selection in the pursuit of effective thermal management.

Best Technology is an expert in metal core PCB manufacturing, we have strong R&D team and full-experienced employs that can provide with you the best metal core PCB solution. Welcome to contact us at sales@bestpcbs.com if you want to know more.

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Do You Know How Does the ENEPIG Working for Wire Bonding Circuit Boards?

Friday, November 10th, 2023

The electronics industry has continuously pursued smaller and faster electronic products with increased functionality. To meet these demands, the electronic packaging industry has focused on developing more advanced packaging methods, aiming to increase the density of components on a circuit board while integrating multiple functions into a densely package.

The increasing density of packaging and interconnection has driven the progression of assembly methods from through-hole technology (THT) to surface-mount technology (SMT). Additionally, the use of wire bonding to connect chips to substrates has become more prevalent. The adoption of smaller interconnect pitches and chip-scale packaging (CSP) has further increased component density, while multi-chip modules (MCM) and system-in-package (SiP) have enabled the integration of more functions on a single package.

This post describes the key factors affecting the reliability of interconnections, with a particular focus on the specific properties of surface-treated wire bonding, emphasizing the selection of wire bonding surface treatments.

Selection of Surface Treatment for Wire Bonding

While electroless nickel gold provides excellent performance for wire bonding, it has three main drawbacks that hinder its application in cutting-edge technologies:

1. The relatively high demand for gold layer thickness leads to lengthy process costs.

2. Thick gold layers are prone to the formation of weak tin-gold intermetallic compounds (IMC), reducing the reliability of solder joints. To enhance solder joint reliability, alternative surface treatments may be used, but this increases additional process costs.

3. The electroplating process requires the use of electroplating lines, limiting the design freedom and wiring density of the packaging substrate.

The limitations posed by electroplated nickel-gold provide an opportunity for the adoption of chemical plating. The techniques of chemical plating include Electroless Nickel Immersion Gold (ENIG), Electroless Nickel Electroless Gold (ENEG), and Electroless Nickel Palladium Immersion Gold (ENEPIG).

Among these three options, ENIG is generally unproblematic due to its lack of high reliability in gold wire bonding properties (although it has been used in some low-end consumer products). On the other hand, ENEG shares the high production cost and presents complex challenges in terms of the manufacturing process, similar to electroplated nickel-gold.

ENEPIG was initially introduced in the late 1990s, its market acceptance was delayed until around the year 2000 due to fluctuations in palladium metal prices (which were inflated to unreasonable levels around 2000). However, ENEPIG can meet the requirements of many new packaging applications, providing reliable performance and conform to lead-free/ROHS requirements, with a recent strong surge in market demand.

In addition to the advantages in packaging reliability, the cost of ENEPIG is another benefit. With the recent rise in gold prices surpassing US$800/oz, it becomes challenging to control costs for electronic products requiring thick gold plating. The price of palladium (US$300/oz), relative to gold, is less than half, making palladium a cost-effective alternative with surface-related advantages.

Comparison of Surface Treatments

Up to now, for printed circuit boards accommodating fine-pitch QFP/BGA components, there are primarily four lead-free surface treatments:

Immersion Tin (IT)

Immersion Silver (IAg)

Organic Solderability Preservatives (OSP)

Electroless Nickel Immersion Gold (ENIG)

The table below compares these four surface treatments with ENEPIG. Among these surface treatments, none can simultaneously meet all the requirements of lead-free assembly processes, especially when considering multiple reflow experiences, pre-assembly shelf life, and gold wire bonding experiences. In contrast, ENEPIG offers good shelf life, solder joint reliability, gold wire bonding capability, and can serve as a touch button surface, providing surface-related advantages. Moreover, in the final gold replacement deposition reaction, the chemical palladium layer in ENEPIG works to protect the nickel layer, avoiding excessive corrosion during gold replacement.

(Table 1 – Comparison_of_Different_Surface_Treatment_Performances)

What Are Advantages of ENEPIG?

ENEPIG has several crucial advantages, demonstrating reliable solderability and gold wire bonding concurrently. The key benefits are outlined as follows:

  • Prevention of “Black Nickel Problem” – The absence of gold replacement attacking nickel on the surface prevents interfacial corrosion.
  • The chemical palladium layer acts as a barrier, preventing copper from diffusing to the surface, ensuring satisfactory solderability.
  • Palladium layer enable to completely dissolves in the solder, preventing the exposure of a high-phosphorus layer at the alloy interface. After the dissolution of the chemical palladium layer, the chemical nickel layer is revealed, forming a satisfactory nickel-tin alloy.
  • Capability to Withstand Multiple Lead-Free Reflow Cycles
  • Excellent Gold Wire Bonding Properties

These advantages make ENEPIG a preferred choice in various applications, ensuring reliable performance in both soldering and wire bonding processes while offering cost efficiency. As a one-stop PCB supplier in Asia, Best Technology possesses advanced technology and high-tech manufacturing equipment that can meet the “multi-variety, small volume, high quality, strong capability, short delivery” requirements. Welcome to contact us if you are going to find a reliable circuit board manufacturer.

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How Can I Reduce and Optimize the Cost of My PCB in A Best Way? – Series 2

Saturday, October 28th, 2023

At our latest blog, may the readers have understood the factors that will affect the PCB price, or maybe one of your have put it into practice that get a price lower than your budget. However, people are always not satisfied by the existing situation. If this is bother you as well, keep reading since this time we are going to sharing some useful tips that enable to optimize your PCB price until to the best.

  • Reduce board complexity

It can be said that try to simplest your design/layout and make it easy to fabricate is the simplest way to reduce your PCB cost. The more complex and irregular the forms, the higher the cost. Just remember: for every circuit board, no need to maintain a fancy diagram to demonstrate its excellence, perform functionality correctly is enough.

  • Design it in right size and thickness

Design your board in right size doesn’t means make it smaller as possible. You must know, if your design is complex and layouts are density, that means maker need to spend more time to assemble them. Highly compact sizes are always expensive, don’t skimp when it counts. Otherwise, more money will be spent to afford what you saved.

And in theory, the more layers and thickness the board, the more cost that manufacturer spend. Numerous layers in the PCB will have an influence for holes and diameters. It is recommended that if thinner thickness is enough, then just do it. 

  • Shapes, holes and rings should be regularly

Normally, keep the PCB as square or rectangular shapes is cheaper than irregular shapes like pentagon.  And large holes and rings enable to smooth the production run and easy to create. For smaller holes and rings means the driller must be smaller and delicate control.

  • Consider volume and choose manufacturer

In our last blog, we emphasize manufacturers will set a minimum order quantity (MOQ), it is common in this industry. So, consider your volume and check multiple quantities before ordering can help to recognize which one is the most cost-effective.

During the evaluation period, talk to your suppliers as soon as possible, knowing more about the material specifications, technical and PCB tolerances. A wrong choice will lead to much time waste and some unnecessary cost. This is we call “trial and error cost”. Try to make all things are clear and correct before production.

  • Pick the best vias

There are totally three types of vias in PCB: though-hole, blind, buried. The through hole can be passed through the whole board, while blind vias is created from top or bottom side to the middle of the board without through to bottom or top side. Buried vias, just as its names, it is buried inside the boards and we can’t see it by naked eyes.

Obviously, through hole is cost performance than other two vias, try to use more instead of blind or buried vias enable to decrease your cost. In additionally, blind and buried vias are always necessary in HDI PCB and RF board, otherwise, you don’t usually use them.

  • Make sure all SMT components on the one side

Trying to make all the surface mounted (SMT) components on the one side of circuit board if possible. In this way, assembler can finish the SMT process in one-time, so that can save much manufacturing time and cost. But if the components are distributed on both sides, it is needed to assemble two times, that is top side first – bottom side second (or sometimes bottom first).

  • Select easily replaceable component parts

It is assumed that one of part on your circuit becomes obsolete, then you must search for replaceable part or update your design if you would like to continuedly use this board. As an extensive experienced PCB manufacturer, we strongly recommend that select components that has standard dimension, so that it is easy to match alternative one.

In addition, visit some manufacturer’s website carefully to see if any components are marked as “obsolete” or “not recommended for new designs” before finishing your design. This enables to avoid secondary update.

  • Follow manufacturer’s PCB fabricate standards

Understand and follow manufacturer’s fabricate standards can keep your unit PCB price in a relative lower cost. When designing a new project, please make sure to following below tips.

  1. Use standard stack-up with standard materials.
  2. Design 2-4 layers PCB if possible.
  3. Keep your minimum line width and spacing within the standard spacing.
  4. Avoid adding extra special requirements as much as possible.
  • Use SMT components as possible

Choose surface mounted (SMT) components instead of through hole (THT) component whenever possible. SMT and THT are almost treated as separated manufacturing processes. Hence, if all the THT components can be replaced by mounted parts, the THT process will be eliminated completely. It is not only decreasing the manufacturing cost, but also reducing delivery time. Of course, it is not always possible, but it’s worth trying.  

Whatever decisions you make, the best solution is to consult and discuss with your suppliers. They be always to give you the best one that can save your money and meet your requirements as well. Meanwhile, if you don’t believe the suppliers, you are welcome to reach us. We promise that we can give you a most favorable price and high-quality product.

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What Factors Affect the PCB Board Price? How to Keep the Best Price? – Series 1

Saturday, October 28th, 2023

For each development engineer or purchaser, how to keep the cost within the budget is a most irksome and irritating assignment while the PCB has the good quality and enable to perform desired function. They need to understand the computation rule and calculate the developing cost. So, it is worth to knowing the factors that affect the printed circuit board price, and it is a must learn course for every engineers. Herein, Best Technology is going to dissect the factors affect the cost of PCB, let’s move on!

What affects the cost of a PCB?

Drives the cost of PCBs are numerous, we can see from the PCB itself, for example, circuit board substrate materials, the external factors such as the manufacturing difficulties, the whole order quantities and some other special requirements that from designers.

Here, we listing some basic parameter factors which drives the whole cost of a PCB.

  • PCB substrate material

The substrate of PCB board refers to the material used in the non-conductor part of the circuit board, mainly FR4, glass fiber, epoxy resin, polyimide, copper, aluminum and so on. In the PCB manufacturing, glass fiber is widely used in the manufacture of double-sided circuit board and multi-layer board, while epoxy resin and polyimide are used in the manufacture of high-density multi-layer board. Among them, copper substrate is most expensive material. No matter what kind of materials, all of them shall be calculated according to the real-time international price.

  • PCB size (panel and single pcs)

PCB size will determine the price of PCBs, this is for sure. Generally speaking, with a same number of PCB layers, the smaller the PCB size, the cheaper the cost. Because during calculating cost, vendors will consider the utilization rate of raw materials. Make sure the highest utilization, the cost for both purchaser and vender will be best. The raw material of PCBs is commonly 1200mm*1200mm, or 1220mm for special specifications, when the utilization achieves 90% or above, this is the best.

So, how to improve the utilization of raw materials? Normally, manufacturers will optimize the working files (WF) from single size to panel size, and then material will be cut according to the panel files. But if the panel size is not suitable, then there will be a lot of waste edges of raw material in the cutting process, and generally this will be added into your PCB price. So that the unit PCB price will be more expensive. In another word, if you PCB size is well-suited, then it is good for PCB manufacturer and yourself. And at this time, the utilization will be the highest and your PCB cost is the cheapest as well.

  • Line width/spacing

To a certain extent, as long as you are following the PCB design rules, the PCB price will not too high. However, if your design is complex and the line width is extreme thin, then the price will increase since it is difficult to control during manufacturing.

  • PCB layers

According to the IPC standard, PCBs can be classified to single-layer PCB, double sided PCB and multilayer PCB. For layer count over than 2 layers, we called it as Multilayer PCBs, such as 4 layers PCB, 6 layers PCB. For FR4 PCB, we can make up to 32layers.

Due to the manufacturing process and some unpredictable assembling cycles, the more the layers, the more expensive it is. (The price of single side PCB is the similar to double sided PCBs.)

  • Solder mask ink color

In the past, it is no doubt that you will spend more if you want every color expect green. But now things are changeable. Most colors are available at no or very little extra cost, which usually only occurs for unique requests such as matte tones.

  • PCB copper foil thickness

The weight of copper foil depends on the successful utilization of the material. Thicker copper is more expensive and comes with additional manufacturing difficulties and expenses. You may also have to fill the holes with copper foil to connect layers. In addition, heavier copper means you need to spend more cost in shipping. Let’s take a simple example, for aluminum core PCB and copper core PCB, in the same volume and quantities, copper core PCB stands out for expensive shipping cost since it has thicker copper and heavier weight.

  • PCB surface treatment

Surface treatment is a method that using for protecting the surface from corrosion and improve the solderability. Usually, in consideration of environmental friendliness, vendors can use a couple of gold or silver to achieve further safety for use in some applications.

The commonly used surface treatment methods include OSP, IMMERSION SILVER, ENIG, ENEPIG and HASL (LF). Among them, the price is ENEPIG>ENIG>IMMERSION SILVER>OSP>HASL. You can calculate the PCB board price according to the surface treatment method and gold thickness.

  • Quantity and lead time

When developing a new project, almost of companies would like to make prototypes first and ask for a sample quotation. However, some PCB manufacturers will set the minimum order quantity, the smaller the quantity, the higher cost the PCB board. Please make sure to check the price for different amount before placing an official order.

Meanwhile, the delivery time request also will affect the whole price in a certain. And certainly, the price of quick turn order and expedited service will higher than normal order.

  • Other special requirements (impedance, IPC standard)

To ensure the stable transmission of circuit board signals and improve the quality of signal transmission, designers and engineers will ask for impedance control for the traces. This can be seen as special requirements, so it will add a few extra prices. And the required IPC Criteria is a factor as well. Normally, if customer does not have other request, we will default use IPC class II. III level will more expensive.

Above all are the mainly factors that affect the price composition for a printed circuit board. When evaluating your PCB cost, making them in your consideration is best.

PCB and PCBA supplier that can save cost for you – Best Technology

When you are seeking for a reliable PCB and PCBA supplier, I would like to recommend Best Technology to you. Best Tech offers one-stop service including raw material purchasing, PCB making, components searching, assembly, box building and package out of warehouse. What we can provide is not limited to PCB, but also metal core PCB, ceramic PCB, flexible PCB, rigid flex PCB, special PCB like HDI PCB, heavy copper PCB, extra thin PCB and so on. During the 17 years, the Best Technology company has served include medical industry, consumer electronics, new energy, automotive electronics, aerospace, military and others.

Could it be said that you are searching for a PCB supplier that can provide favorable price that lower than market? If this is true, please go ahead and reach us today, let’s talk about more PCB information right now and start our business trip together. We promise, when you decide to take the first step, and we’ll take the remaining 99 steps.

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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_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.

(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.

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