Best technology engaging in the PCB manufacturing and PCB design for more than 17 years. With a strong R&D team, we can provide customers with fast and valued PCB design solutions. Here is one of our industrial motherboard design & industrial PCB case sharing for your reference. If you want to get your own industrial PCB design, welcome to contact us.
A mITX architecture industrial control motherboard
[5]：2x USB 3.0 (Internal) + 1x USB 3.0 (Client) + 2x USB 3.0 (Rear I/O) + 2x USB 2.0 (Rear I/O) +
2x USB 2.0 (Front Header) + 1x USB 2.0 (mPCIe)
Industrial PCB Design Considerations
Control the length of the circuit: Minimize the length of the circuit, especially the key signal lines, to reduce signal attenuation and delay.
Avoid sharp angles and right angles: Right angles and sharp angles should be avoided when wiring, and rounded or 45 degree angles should be used as far as possible to reduce signal reflection and impedance discontinuity.
Line width: Determine the line width according to the current size and thermal requirements to ensure the reliability and stability of the circuit.
Inter-layer wiring: Rational use of multi-layer PCB inter-layer wiring, such as the signal line on the inner layer, power and ground wire on the outer layer.
Impedance control: For high-speed signals, it is necessary to control the line impedance to ensure signal integrity, and carry out impedance matching design if necessary.
Avoid cross and parallel wiring: Try to avoid cross and parallel wiring of signal lines to reduce crosstalk and electromagnetic interference.
Contact us if you have any questions and inquiry about industrial PCB design projects.
In the design of electronic devices and systems, power distribution and heat dissipation management are key factors. Bus bar PCB, as an efficient solution, is particularly outstanding in these aspects. In this article, we would like to introduce the advantages of Bus bar PCB and its applications in different industries.
What Is A Bus Bar PCB?
At the beginning, we should know what a bus bar PCB is. The Bus bar PCB is a special and newest design that integrates the FR4 material and metal alloy into a whole product, which allows the current transfer path into the circuit board. Due to the current carry capacity and special shape, it also called busbar PCB, embedded bus bar PCB, extruded copper PCB, copper inlay PCB, copper extrusion PCB.
Bus bar circuit board provide a more compact and efficient means of current distribution than traditional wires and cables. This design improves the overall performance of the electronic system by reducing inductance, increasing current carrying capacity, and optimizing heat dissipation.
What Are the Advantages of Bus Bar PCB?
Bus bar PCB offers numerous benefits when be using the power supply applications, its main functions are:
1. Reduce the inductance
Bus bar PCBs reduce inductance by allowing current to flow between tightly spaced conductors. This layout reduces the loop area and thus the inductance value. This is particularly important for high-frequency and highspeed applications, as it reduces voltage spikes and noise, improving system stability and performance.
2. Enhanced current carrying capacity
Due to its large cross-sectional area and high-quality conductive materials, Bus bar PCB can efficiently carry large currents. This is particularly useful in applications that require a large amount of power distribution, such as power supplies, electric vehicles, and renewable energy systems. Bus bar PCBs support higher current density compared to conventional PCB wiring, which improves thermal management and reliability.
3. Improve thermal management
The Bus bar PCB effectively dissipates heat generated by key components. In high power applications, the buildup of heat can affect performance and life. The Bus bar PCB helps maintain optimal operating temperatures through efficient heat distribution, reducing the need for additional cooling mechanisms.
4. Save space and weight
The compact design of the Bus bar PCB reduces the overall size and weight of the electronic components. Its simple construction and elimination of multiple wire connectors contribute to space savings. This is particularly beneficial for applications where size and weight are critical, such as the aerospace and automotive industries.
5. Improved reliability and durability
Bus bar PCBS have superior mechanical strength and durability compared to traditional wiring systems. Its robust construction and secure connections reduce the risk of loose connections, failure due to vibration, and mechanical wear. This improves system reliability and service life for harsh environments and demanding applications.
6. Simplify assembly and maintenance
Using a Bus bar PCB simplifies the assembly process because it reduces the number of individual wires and connectors. This not only speeds up installation, but also reduces assembly errors. In addition, the Bus bar PCB provides a more orderly and accessible layout for easy troubleshooting and repair.
7. Cost effective
Although there may be a high initial cost, Bus bar PCBs can provide cost savings in the long term. Its advantages in reduced inductance, improved thermal management and enhanced reliability reduce operating and maintenance costs. In addition, Bus bar PCB reduces the need for addons, such as heat sinks or complex wiring bundles, thereby increasing overall cost effectiveness.
What Applications of Bus Bar PCB?
Due the high current carry capacity of the bus bar PCB, makes it very suitable for power supply or power management devices. Bus bar PCB can perform well in such fields. Here are some common application examples that bus bar PCB can be used for. If you are seeking for a PCB to integrate into your power supply project, then bus bar PCB is the go-to-choice.
1. Power Electronics
In power converters, inverters and high-current power supplies, Bus bar PCBS are widely used because of their ability to efficiently handle high currents and excellent thermal performance.
2. The Automobile industry
Another popular field that bus bar PCB used in is automotives, especially in electric vehicles (EVs) and hybrid electric vehicles (HEVs). In the electric cars, it can be used for battery connectivity and power distribution, contributing to weight reduction and performance improvements.
3. Renewable energy
Bus bar PCB is an environment friendly material, it is often used in solar systems, wind turbines and energy storage solutions to manage high currents and enhance reliability.
4. Industrial equipment
In industrial machinery and equipment, Busbar PCB provides powerful and efficient power distribution for motors, drives and control systems.
5. Aerospace
Bus bar PCBS are used in aerospace applications, such as avionics and power distribution systems, where size, weight and reliability are key factors.
Final Words
All in all, bus bar PCB offers significant advantages in handling high currents, improving thermal management, and providing reliable power distribution across various applications. By integrating bus bar PCBs, industries can achieve better power management, reduced system size and weight, and improved overall reliability.
Best Technology is a one-stop PCB solution provider in Asia, we offer various kinds of PCBs not only include bus bar PCB, but also Extra thin PCB, RF PCB, HDI PCB, Heavy copper PCB, Ceramic PCB, Metal Core PCB, Flex PCB and rigid flex PCB, PCBA and so more. We have more than 17 years-experience in PCB design and manufacturing, and served more than 1200 customers. Choosing Best Technology as your supplier ensures you get high quality PCBs, helping to improve the performance and competitiveness of your products. Contact us right now to customize your own PCB!
High-Density Interconnect (HDI) PCBs are revolutionizing the electronics industry with their advanced capabilities and compact designs. As technology continues to evolve, the demand for smaller, faster, and more efficient electronic devices has led to the widespread adoption of HDI PCBs.
What is Definition of HDI PCB?
HDI board refers to High Density Interconnect, that is, high density interconnect board, which is a relatively new technology developed by the PCB industry at the end of the 20th century.
The drilling of the traditional PCB board is affected by the drilling tool, and when the drilling aperture reaches 0.15mm, the cost is already very high, and it is difficult to improve again. The drilling of HDI board no longer relies on traditional mechanical drilling, but uses laser drilling technology. (This is why it is sometimes called a laser plate.) The hole diameter of the HDI board is generally 3-5mil (0.076-0.127mm), the line width is generally 3-4mil(0.076-0.10mm), the size of the pad can be greatly reduced, so more line distribution can be obtained within the unit area, and the high-density interconnection comes from this.
Smaller device spacing, more I/O pins and embedded passive devices Larger ASiCs and FPGAs with increasingly shorter rise times and higher frequencies all require smaller PCB feature sizes, which is driving a strong demand for HDI/ micro through-holes. The typical high density interconnector designs are including:
1+N+1
2+N+2
3+N+3
4+N+4
What are the benefits of HDI PCB?
HDI is a compact circuit board designed for small volume users. Compared with ordinary FR4 PCB, the most significant feature of HDI is the high wiring density, and the difference between the two is mainly reflected in the following three aspects.
1. HDI is smaller and lighter
HDI board is a traditional dual panel as the core board, through continuous stacking layer by layer. This kind of circuit board made by continuous layering is also called Build-up Multilayer (BUM). Compared with traditional circuit boards, HDI circuit boards have the advantages of “light, thin, short and small”.
The electrical interconnection between the HDI board is realized through the conductive through hole, buried hole and blind hole connection, its structure is different from the common multi-layer circuit board, and a large number of micro-buried blind holes are used in HDI board. HDI uses direct laser drilling, while standard PCBS usually use mechanical drilling, so the number of layers and aspect ratio tend to be reduced.
The high density of HDI board is mainly reflected in the hole, line, pad density, and layer thickness.
â— Micro-via hole
The HDI board contains the design of micro-pilot holes such as blind holes, which is mainly reflected in the micro-hole formation technology with a diameter less than 150um, and the high requirements of cost, production efficiency and hole position precision control. In the traditional multilayer circuit board, there are only through holes and no tiny buried blind holes.
â— Fine line width and line distance
Its main performance in the wire defects and wire surface roughness requirements are more and more stringent. Generally, the line width and line distance do not exceed 76.2um.
â— High pad density
The density of welded contacts is greater than 50 per square centimeter.
â— Thinning of medium thickness
It is mainly manifested in the trend of the thickness of the interlayer medium to 80um and below, and the thickness uniformity requirements are becoming more and more stringent, especially for high-density plates and packaging substrates with characteristic impedance control.
2. Better electrical performance
HDI not only enables end-product designs to be miniaturized, but also to meet higher standards of electronic performance and efficiency at the same time.
The increased interconnect density of HDI allows for increased signal strength and improved reliability. In addition, the HDI board has better improvement for RF interference, electromagnetic wave interference, electrostatic discharge, heat conduction and so on. HDI also uses full digital signal process control (DSP) technology and a number of patented technologies, with a full range of load adaptability and strong short-term overload capability.
3. The HDI board has very high requirements for buried holes
It can be seen from the above that whether it is the volume of the board, or the electrical performance, HDI is better than ordinary PCB. Where the coin has two sides, the other side of HDI is as a high-end PCB manufacturing, its manufacturing threshold and process difficulty are much higher than ordinary PCB, and there are more problems to pay attention to when producing – especially the buried hole jack.
What are the basic parameters of HDI PCB?
HDI PCB has greater different with normal FR4 PCB, from the stack up, material selection, manufacturing and cost. So, it is vital to understanding the basic parameters of a high-density interconnect board before start your designing trip. The standard parameters of HDI board mainly include the following aspects:
Numbers of layers
Generally, the number of layers of HDI board is 4-20 layers, and the high-end HDI board can reach to 40-50 layers.
Line width/spacing
Due to the HDI PCB are always used in high-end applications, their line width and spacing are usually very strict, and the common requirement is that the line width/spacing is 4/4mil (0.1mm), or even smaller.
Blind hole, buried hole, bus
These are one of the characteristics of the HDI board, blind hole and buried hole can reduce the area of the circuit board, make your design more density, and the bus enable to improve the signal transmission rate of the PCB.
Board thickness
The board thickness of HDI board is usually range from 0.8 to 3.2mm, of which 1.6mm is the most common thickness.
Pad
The pad on the HDI board is generally very small, and the common pad size is 0.2mm to 0.5mm. Different factory has different capabilities, it is best to ask your supplier or manufacturer to get a manufacturing capability document.
Impedance control
For high-speed signal transmission circuits, the impedance control of the HDI board is very important, and the requirements are very strict. It is needed to tell your vendor if your HDI board will be used in high-speed devices.
Material
The main materials of HDI board are FR4, BT, PI, PET, etc. Different materials can meet different requirements.
This is the end of this sharing, contact us today to learn more about our HDI PCB solutions and how we can help you achieve your technological goals. In our next chapter, we will introduce the manufacturing process and methods of HDI boards, let me know if you are interested in it.
In PCB design, engineers often use via holes to connect the same electrical network located in different layers, vias and through holes PAD is very similar, the difference is that through holes pad is generally used to insert plug-in components, while via holes are generally small. Vias are very popular in some complex and multi-layer design, because it can serve as a pathway between the different layers.
What are vias in printed circuit boards (PCBs)?
Vias in printed circuit boards (PCBs) are essentially small holes that are drilled or etched into the board’s surface. Â These small, cylindrical holes are plated with conductive material, typically copper, to ensure electrical continuity between the layers. They serve as conduits for electrical connections between different layers of the PCB or between components mounted on the surface of the board and the internal circuitry.
They are important for creating multilayer PCBs, where multiple layers of copper traces are separated by insulating layers. Without vias, it would be impossible to establish connections between these layers, limiting the complexity and functionality of electronic devices.
A via hole in PCB is mainly composed of three parts, hole, pads around the holes, and power layer isolation area. The process of via hole is to plate a layer of copper foil on the cylindrical surface of the hole wall by chemical deposition to connect the copper foil that needs to be connected in the middle of each layer. In this way, the upper and lower sides of the hole are made into ordinary pad shape, which can be directly connected with the traces of the upper and lower sides. The wall thickness of the plating is 1mil or 2mil, and completed hole diameter may be 2mil-4mil smaller than the drilled hole.
Why Employ Vias in PCBs?
Vias in PCBs primarily facilitate electrical connections across different board layers, enabling designers to craft intricate and compact circuit layouts by permitting signal and power traversal through layers. This capability is paramount in multi-layer PCBs, where space is constrained, and high-density component placement is requisite.
Space Optimization
Vias permit the stacking of multiple circuit layers, optimizing PCB real estate, resulting in more compact devices.
Enhanced Electrical Performance
Providing direct electrical signal pathways, reducing interference and loss, thereby enhancing overall circuit performance.
Thermal Management
Thermal vias, specifically engineered for heat dissipation, aid in managing PCB temperatures, ensuring component reliability and longevity.
Design Flexibility
Vias afford greater flexibility in routing traces and component placement, fostering more innovative and efficient PCB designs.
What are the different types of vias used in PCB design?
There are several types of vias, each serving different purposes based on their placement and function. Understanding the different types and their applications is crucial for designing efficient and reliable PCBs. The most common types include through-hole vias, blind vias, and buried vias. Each offers unique advantages depending on the design requirements and constraints of the PCB.
1. Through-Hole Vias: These are the most common type of vias, extending through the PCB’s entire thickness, linking all layers. They are straightforward to manufacture and cost-effective.
2. Blind Vias: These vias connect an outer layer of the PCB to one or more inner layers but do not go through the entire board. They conserve space and simplify board layout complexity.
3. Buried Vias: Located entirely within the inner layers of the PCB, buried vias connect two or more internal layers without reaching the outer surfaces. They are useful for high-density and multi-layer PCBs where space is limited.
4. Micro Vias: Smaller than standard vias, micro vias are typically utilized in high-density interconnect (HDI) PCBs. They can connect adjacent layers or span multiple layers using stacked or staggered configurations.
What is the difference between a PCB hole and a via?
The terms “PCB hole” and “via” are often used interchangeably, yet they denote distinct features within a PCB:
PCB hole generally refers to any drilled PCB hole, serving various purposes such as mounting components (e.g., plug-in components), positioning holes or mechanical mounting points. PCB holes are not necessarily conductive. While vias specifically denotes a conductive hole connecting different PCB layers. They are plated with conductive materials, usually copper, to ensure electrical continuity between layers.
In essence, while all vias are PCB holes, not all PCB holes are vias. Vias are a subset of PCB holes with the specific function of establishing electrical connections between layers, whereas PCB holes can serve a broader range of purposes, including mechanical and non-electrical functions.
What should we consider when designing vias in PCB?
In a PCB design, seemingly simple via holes often bring great negative effects to the design of the circuit. In order to reduce the adverse impact of the parasitic effect of the hole, PCB engineers can try their best to consider below points:
Vias cannot be designed on the pads.
The area extending 1.5mm outward from the contact region between the device’s metal housing and the PCB should not design any vias.
Vias should not be present in the areas where adhesive dots are applied or printed for surface-mount components, such as the PCB areas beneath CHIP and SOP components when using adhesive dot application or printing processes.
In principle, through-hole diameters should be at least 0.2mm (8mil) with an outer diameter of at least 0.4mm (16mil). For some special areas, the outer diameter must be controlled to 0.35mm (14mil).
For BGA designs with a pitch of 0.65mm and above, it is advisable to avoid using blind or buried vias, as they significantly increase costs.
The spacing between vias should not be too close to prevent drilling from causing breaks. Generally speaking, the hole spacing should be 0.5mm or more. Spacings of 0.35mm-0.4mm should be avoided as much as possible, and spacings of 0.3mm or less are prohibited.
The number of vias used for power trace inter-layer connections should meet the current carrying requirements, which is 1A per 0.3mm diameter via.
This is the end of this informational sharing, welcome to contact us if you want to know more about PCBs.
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.
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.
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.
Due to the growing concerns and advocacy for environmental friendliness, as well as the prohibition of harmful substances like lead (tin), an increasing number of industries are moving away from the use of HASL (Hot Air Solder Leveling) technologies for PCB (Printed Circuit Board) surface treatment. The current trend is to use other surface treatments such as OSP, gold plating, immersion tin, immersion silver, ENIG and ENEPIG. Among them, immersion silver becoming a popular choice since it has excellent performance and cost effectiveness.
What is Immersion Silver Finish?
Immersion silver finishing is an environment friendly surface treatment that coating a layer of silver (about 0.1~0.4um) on the copper surface to ensure the good solderability when assembly. When comparing its functional performance with other surface finishes like OSP and ENIG, immersion silver falls between them. It exhibits outstanding solderability and exceptional solder joint strength, surpassing OSP, which lacks a conductive barrier. However, when employed as a contact surface, immersion silver demonstrates lower strength compared to gold.
What is the Working Principle of Immersion Silver?
Immersion silver finishing uses chemical deposition to finish the whole processes. Electrochemical deposition is a method of reducing and depositing metals onto the surface of an object by controlling the current in a solution. In the immersion silver process, the pad serves as the anode (positive electrode), while silver acts as the cathode (negative electrode), with a current applied between them. This causes silver ions (Ag+) to be reduced to silver metal under the influence of the electric field, subsequently adhering to the pad surface and gradually forming a silver layer.
The displacement reaction of immersion silver is:
2Ag+ + Cu = 2Ag + Cu++
This method utilizes both electrical current and chemical reactions to deposit silver from the solution onto the surface of the PCB pad, creating a uniform and porous silver layer.
Silver Plated Analyzing: Pros vs Cons
Before selecting the immersion silver coating, we should understand its advantages and disadvantages to consider whether it is suitable for your PCB project and end-applications.
Pros of immersion silver:
Cost-effective than immersion gold
Good surface flatness and low contact resistance
Corrosion resistance
Good solderability, especially for BGA chips or smaller components
Environment friendly
High reliability
Cons of immersion silver:
Difficult to handle, must wear gloves
Special storage conditions – if the package is opened and not all PCBs need to be used, it must be resealed quickly or use them within 24h.
Peelable masks can’t to use
Important Points You Must Know About Storage
For storage and handling, it needs more careful than immersion tin and OSP.
It is compliant with ROHS and safer than HASL.
In the dry conditions, it can be stored 6-12months.
PCB with immersion silver must be soldered within 24hours if package is unsealed.
If the immersion silver PCB has been stored for more than 12 months, a solderability testing is must before assembling.
Immersion Silver vs ENIG
ENIG also is a common surface treatment in the PCB manufacturing, its full name is Electroless Nickel/Immersion Gold finishing. The ENIG technology is a relative expensive than immersion silver, and it suitable for more complex layout design.
ENIG plating involves safeguarding the copper pads on PCBs by first applying a layer of nickel and then overlaying the copper surface with a thin layer of gold. In essence, the procedure is akin to immersion silver, but it significantly improves PCBs by providing enhanced resistance to oxidation, superior solderability, and excellent surface planarity.
Let’s review the performance comparison between these two surface treatments:
Welcome to contact us if you have any questions about immersion silver or other surface treatment.
The resistance and capacitance buried in multi layers PCB process is a process of burying resistors and capacitors inside the PCB board. Usually, the resistors and capacitors on the PCB are directly soldered on the board through mounting technology, while the buried resistor and capacitor process is to embed the resistors and capacitors into the internal layer of the PCB board.
This kind of printed circuit board consists of a first dielectric layer, a buried resistor, a circuit layer and a second dielectric layer in order from bottom to top. Among them, the part of the buried resistor without a circuit layer on the buried resistor is covered with a polymer isolation layer, and the surface of the polymer isolation layer is roughened, the surface roughness Rz is bigger than 0.01 μm, and the thickness of the polymer isolation layer at the corners is at least 0.1 μm.
The printed circuit board of the utility model covers a layer of polymer isolation layer on the surface of the buried resistor, thereby protecting the buried resistor from being attacked and corroded by chemical chemicals during subsequent wet processes such as browning and super-coarseness, and improving the efficiency of manufacturing buried resistors. Resistor plate process capabilities further promote the application of buried resistive plates to inner layer buried resistors.
The advantages of the buried resistor and buried capacitor process include:
1. Space saving:
Since the resistors and capacitors are embedded directly into the internal layers of the board, space on the PCB board can be saved, making the entire circuit board more compact.
2. Reduce circuit noise:
Embedding resistors and capacitors into the internal layers of the board can reduce the electromagnetic interference and noise of the circuit and improve the stability and anti-interference capabilities of the circuit.
3. Improve signal integrity:
The buried resistance and buried capacitance process can reduce the transmission delay and reflection loss of circuit signals and improve the integrity and reliability of signal transmission.
4. Reduce the thickness of the PCB:
However, the buried resistor and buried capacitor process is relatively complicated in terms of manufacturing and repair, because the resistors and capacitors cannot be directly observed and replaced. In addition, the buried resistance and buried capacitance process is usually used in high-end electronic products, and the cost is relatively high.
When it comes to high-density circuit design, PCB buried resistance and buried capacitance technology has become a very useful technology. In traditional PCB layout, resistors and capacitors are usually soldered on the PCB surface in the form of patches. However, this layout method causes the PCB board to take up more space and may cause noise and interference on the surface.
The buried resistance and buried capacitance process solves the above problems by embedding resistors and capacitors directly into the internal layer of the PCB board.
The following are the detailed steps of the PCB buried resistor and buried capacitor process:
1. Make the inner layer:
When making a PCB board, in addition to the conventional layers (such as outer layer and inner layer), it is also necessary to make a separate inner layer specifically for buried resistance and buried capacitance. These internal layers will contain areas for buried resistors and capacitors. The inner layers are usually made using the same techniques as regular PCB manufacturing, such as electroplating, etching, etc.
2. Resistor/capacitor footprint:
Resistors and capacitors are packaged in a special package in the buried resistor and capacitor process so that they can be embedded into the internal layer of the PCB. These packages are usually thinned to accommodate the thickness of the PCB board and have good thermal conductivity.
3. Buried resistor/capacitor:
In the process of making the inner layer, the buried resistor and capacitor process is completed by embedding resistors and capacitors into the inner layer of the PCB board. This can be achieved through a variety of methods, such as using special pressing techniques to embed resistors and capacitors between inner layers of material, or using laser technology to etch holes in the inner layer material and then fill them with resistors and capacitors.
4. Connection layer:
After completing the inner layer of the buried resistor and buried capacitor, connect it to other regular layers (such as the outer layer). This can be achieved through conventional PCB manufacturing techniques such as lamination, drilling, etc.
In general, the buried resistance and buried capacitance process is a highly integrated technology that embeds resistors and capacitors in the internal layer of the PCB board. It can save space, reduce noise, improve signal integrity, and make PCB boards thinner and lighter. However, due to the complexity, the buried resistor and buried capacitor process is usually used in high-end electronic products with higher performance requirements.
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.
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.
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 costâ€. 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.
Use standard stack-up with standard materials.
Design 2-4 layers PCB if possible.
Keep your minimum line width and spacing within the standard spacing.
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.
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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