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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.

What Is Ceramic Metallization Technology? – Series 1

Saturday, October 7th, 2023

Due to the different surface structures of ceramic susbtrates and metal materials, welding/soldering often cannot wet the ceramic surface or form a strong bond with it. Therefore, the joining of ceramics and metals is a special process, which called as metallization.

What Ceramic Metallization Technology Is?

Ceramic metallization refers to the process of firmly attaching a thin layer of metal film to the surface of a ceramic material to achieve a bond between the ceramic and metal. There are various methods for ceramic metallization, commonly including molybdenum-manganese (Mo-Mn) method, directly copper plate (DPC), directly bonded copper (DBC), active metal brazed (AMB) method and more.

Which Ceramics Can Be Used Metallization Technology?

At present, there are four common ceramic substrates that always used for metallization, they are BeO, Al2O3, AlN and Si3O4. But different ceramic has different characteristics, so its metallization method also is different.

BeO Ceramic

The most common method for metallizing BeO ceramics is the Mo-Mn method. This involves applying a paste-like mixture of pure metal powders (Mo, Mn) and metal oxides to the ceramic surface, followed by high-temperature heating in a furnace to form a metal layer.

Al2O3 Ceramic

The primary metallization methods for Al2O3 ceramics are DBC and DPC. This method involves placing a treated copper foil on the surface of Al2O3 ceramics, introducing an inert gas with a certain oxygen content, and then heating. During heating, the copper surface undergoes oxidation, and when the temperature reaches the eutectic liquid phase region, a eutectic liquid phase is formed, wetting both Al2O3 ceramics and copper, achieving a tight bond. In a chemical sense, the adhesion used by DBC is stronger than DPC since it has thicker copper.

AlN Ceramic

Common methods for AlN ceramics include DBC and Active Metal Brazing (AMB). DBC is similar to the method used for Al2O3 ceramics but requires pre-oxidation treatment of AlN ceramics since AlN is a non-oxide ceramic. AMB involves connecting AlN ceramics and copper foils using active metal brazing materials, often Ag-Cu-Ti alloys.

Si3N4 Ceramic

Si3N4 ceramics cannot be directly metallized using the direct copper plating method because they do not generate an oxide layer on the surface like AlN ceramics. Si3N4 ceramics are typically connected to metals using the AMB method, where chemical reactions between Si3N4 and active metals (Ti, Cr, V) form continuous nitride layers at the interface.

What is the Metallization Temperature?

During the metallization process, the sinter temperature should be controlled strictly. Normally, it can be divided into four ranges:

Ultra-High Temperature (Above 1600°C):

This temperature range is reserved for specific applications where extreme heat resistance is required.

High Temperature (1450°C to 1600°C):

High temperatures are essential to ensure that the glass phase spreads and migrates effectively, enabling a strong bond. However, excessively high temperatures can lead to reduced metallization strength.

Mid-Temperature (1300°C to 1450°C):

This range is chosen to balance the need for effective metallization with the preservation of material properties.

Low Temperature (Below 1300°C):

Lower temperatures are used when the primary concern is avoiding thermal stress on the materials involved.

Proper high sintering temperature is necessary, otherwise, the glass phase will not spread and migrate. But if the temperature is too high, the metallization strength will be poor. So, choose a suitable temperature is important to make sure the metallization effective.

This is all the information about metallization technology, in our next blog, we will delve into what factors will affect the metallization. If you are interested in metallization or other technologies about ceramic circuit boards, please leave your message and keep your eyes in Best Technology website.

What Is The Difference Between Thin Film and Thick Film Ceramic PCBs?

Monday, September 25th, 2023

We know due to the rapid development of electronic devices, Ceramic circuit boards have gradually developed into an ideal packaging substrate for a new generation of integrated circuits and power electronic modules. Among them, thick film ceramic substrate and thin film ceramic PCB are the most popular ceramics that be used in package, because they are made by metallization process.

Why use film technology?

Compared with three-dimensional ceramic materials, film has relatively thin thickness and small size, it can be regarded as a two-dimensional structure. Thick film is made by printing process, the thick film can be made independently and the thickness is usually 10~25μm. Thin film is formed by the composition of the conductor materials and it was sputtering on the ceramic substrate directly. Normally the thickness of thin film is equal or less than 1μm. If the metallization thickness between 1μm to 10μm, then we called it as Directly Plated Copper (DPC) ceramic circuit board.

Thick Film Technology

Thick film technology is a method of direct deposition of slurry on substrate through screen printing technology, and sintering at high temperature to form conductive traces and electrodes. After the material is sinter at high temperature, it will form a strong adhesion film on the ceramic circuit board, and after repeated many times, it will form a multi-layer interconnected ceramic circuit board with resistor or capacitor. The thick film manufacturing process is more easier than thin film.

Thin Film Technology

Thin film ceramic PCB is a chip manufacture technology, which is the main method of metal film deposition in microelectronics fabrication. It was made through evaporation and PVD process firstly to deposited a 200-500nm copper layer as the seed layer. Then using electroplating process to increase the copper foil to required thickness. Finally through stripping and etching to generate the circuits. Thin film ceramic circuit is widely used in LED package fields because its fine traces, high accuracy and heat dissipation.

(Manufacturing_process_of_thin_film_ceramic)

Thin film and Thick film ceramic PCB comparison

In addition to the technology manufacturing difference, their performance and limitations also is different. Here we summarized in below table:

Technology	Thick Film	Thin Film
Conductor thick	10-25um	<=1um
Manufacture process	Screen printing, sinter	PVD, DES
TCR	(50-300) *10-6/C	(0-50) *10-6/C
Cost	Relatively Low	High for prototype
Line width	Thicker line width	Fine traces, suitable for RF
Bonding ability	Not suitable for bonding	Good for wire bonding
Resistance	Available	Need mount resistors
Solder mask	Available	Available

Application difference between Thin film and Thick film ceramic PCB

The applications of thin film and thick film also are different because of their different features. Thick film ceramics are widely used in high power devices such as automotive field, power electronics, aerospace due to its ability to handle high current and voltage. Thick film enables to provide excellent thermal management and can dissipation heat effectively. Thin film ceramic PCBs trend to micro-electronics and RF devices because of its fine lines, low resistance, and high-frequency performance.

Each technology has its unique advantages and limitations, it needs to be properly used to make it suitable for different electronic devices and industries. Choose the right ceramic PCB substrate for laymen is a big challenge, so seeking for a reliable supplier is important. Best Technology engaging ceramic circuit board manufacturing for over 10 years. And our core engineering team are deep in this industry for more than 20 years, we are so confident that we can provide the best solution for you. If you are interested in this, welcome to contact us at sales@bestpcbs.com.

Why do ceramic substrates contribute to the breakthrough of 905nm lidar technology?

Friday, September 1st, 2023

LiDAR (Light Detection And Ranging, referred to as “LiDAR”) measurement is a system that integrates three technologies: laser, GPS (Global Positioning System), and IMU (Inertial Measurement Unit, inertial measurement unit), used to obtain data and Generate accurate DEMs (Digital Elevation Models). The combination of these three technologies can highly accurately locate the spot of the laser beam on the object, and the ranging accuracy can reach the centimeter level. The biggest advantage of lidar is accurate, fast, and efficient operation.

Lidar is currently widely used in the field of driverless cars and robots. It is known as the “eye” of a generalized robot. It is an active measurement device that measures the precise distance between an object and a sensor by emitting laser light.

As an indispensable sensor for L3 and above automatic driving, lidar has significantly improved the reliability of the automatic driving system with its excellent ranging capability, high angular resolution and sensitivity to ambient light, and has become the key to improving reliability. A key element of autonomous driving systems, but its application is constrained by cost and technical challenges.

In the past, lidar was difficult to apply to mass-produced vehicles due to its high cost. However, recently, with the continuous evolution of technology and market competition, the cost of lidar has gradually decreased, thereby accelerating its application in the field of autonomous driving.

In this evolution process, the emergence of ceramic substrates has played a vital role in the breakthrough of lidar technology – 905nm wavelength lidar has become mainstream. Traditional materials such as FR-4 and FE-3 are difficult to meet the high heat dissipation requirements of lidar, while ceramic substrates rely on their excellent thermal conductivity. For example, the thermal conductivity of aluminum nitride ceramic substrates is as high as 200W/M.K. It effectively solves the heat dissipation problem and provides a guarantee for the stability and life of the lidar.

In lidar, the transmitter is one of the links with the highest value and the highest barriers. On the transmitter side, with the rise of China’s domestic industrial chain and the adjustment of the overall technical route of the industry, among them, 905nm VCSEL laser chips and other products have achieved breakthroughs in the market and become a hot topic in the industry.

The “heart” of the transmitter is the light source. Laser transmitter is the core component of laser technology, and its composition includes laser working medium, excitation source and resonant cavity. In this system, why choose a ceramic substrate as a component? The main reason lies in its unique advantages in heat dissipation. Especially for VCSEL (Vertical Cavity Surface Emitting Laser) chips, due to their low power conversion efficiency, the problem of heat dissipation is particularly prominent. The application of ceramic substrates has become the best choice to solve the problem of thermoelectric separation.

The ceramic substrate has excellent heat dissipation performance and can effectively conduct the heat generated inside the laser transmitter. The high thermal conductivity of the ceramic substrate allows it to efficiently conduct heat generated inside the lidar, preventing performance degradation due to overheating. In addition, ceramic materials have the advantages of high strength, hardness, thermal shock resistance, insulation, and chemical stability, which can further extend the service life of products, improve sensitivity, and enhance the response speed of lidar.

Ceramic substrates also enable high-density assembly, supporting miniaturization and integration of devices. Its stability ensures that the sensor signal is not distorted, and the matching with the thermal expansion coefficient of the chip ensures the reliability of the product in harsh environments such as high temperature, high vibration, and corrosion. In addition, the metal crystallization performance of the ceramic substrate is excellent, which ensures the stability of the circuit and further improves the quality control level of the lidar.

As a leading manufacturer of ceramic substrates, Best Technology provides a variety of ceramic substrates of different materials, including 96% alumina, 99% alumina, aluminum nitride, zirconia, silicon nitride, sapphire ceramic bases, etc. The heat dissipation properties of these different materials are different, such as aluminum nitride (AlN): thermal conductivity of 170-230 W/mK, silicon nitride (Si3N4): thermal conductivity of 20-80 W/mK, sapphire (Al2O3): thermal conductivity Coefficient 25-40W/mK.

Therefore, choosing a high-quality ceramic substrate not only helps to solve the problem of thermal and electrical separation of laser emitters, but also provides stable heat dissipation and electrical performance, providing reliable support for efficient operation and performance improvement of laser emitters. In the development of lidar technology, ceramic substrates play an increasingly important role, providing key support for performance breakthroughs and innovations in laser transmitters. We are witnessing a revolution in the auto industry brought about by China’s autonomous driving assistance systems.

If you are designing a ceramic PCB and seeking a reliable manufacturer, welcome to leave you message or contact us directly.

Can I Design Via Holes in Thick Film Ceramic Boards?

Tuesday, April 18th, 2023

May some engineers or designers who be interested in thick film ceramic circuit are curious about can thick film ceramic boards design with via holes like FR4 PCB? Herein, we will explore the feasibility of using thick film ceramic boards for via holes, including the materials and processes involved, as well as the advantages of this approach.

What is thick film ceramic board?

The “Thick Film” refers to the thickness of conductor layer on a Ceramic PCB. Normally the thickness will be at least 10um, around 10~13um, which is thicker than spurting technology in Thin Film Ceramic PCB. And of course thickness is less than DCB Ceramic board or FR4 board.

Thick film ceramic circuit enables to put resistor, electric capacitor, conductor, semi-conductor, and interchangeable conductor on ceramic board, after manufacturing steps of printing and high temperature sintering. The more important thing is by using thick film technology, we can make all the resistors with the same value, or different value for different resistor on the same board.

Materials and processes for via holes

In general, thick film ceramic circuit is not suitable for designing via holes. Because the characteristics of thick film ceramic board mainly depends on the insulation properties of its ceramic substrate, rather than conductive properties. The conductivity of thick film ceramic plate is not good than Metal Core PCB, or even we can say it has a very poor conductivity, usually can’t meet the requirements of the via hole.

But, designing via holes in thick film ceramics is available in Best Technology. Generally speaking, the fabrication of via holes in thick film ceramic boards typically involves several key materials and processes.

From the designer’s perspective, a conductive material is used to create a continuous conductive path from one side of the ceramic board to the other. Common conductive materials include gold paste, silver paste, and copper paste. These materials are usually screen printed onto the ceramic board in the desired pattern, and then fired at high temperatures to achieve sintering and form a conductive layer.

Once the conductive layer is formed, the via holes are created by drilling or punching small holes through the ceramic board at the desired locations. These holes are then filled with a conductive material, such as silver paste or copper paste, to establish electrical connections between the different layers of the circuit.

Finally, the via holes are fired again at high temperatures to achieve sintering and ensure good adhesion and electrical performance.

Advantages of Via Holes in Thick Film Ceramic Boards

These via holes offer several advantages in the design and fabrication of thick film ceramic boards, including as following:

Electrical connectivity

Via holes provide electrical connectivity between different layers of a thick film ceramic board. They allow for the interconnection of different circuitry or conductive layers, enabling the flow of electrical signals or power between different parts of the board. This allows for complex and multi-layered circuit designs, which can be highly beneficial in applications that require intricate circuitry or high-density interconnects.

Space-saving

Via holes can provide a means of vertical interconnection, allowing for more efficient use of board real estate. Instead of routing traces or conductors on the surface of the board, which can take up valuable space, via holes can be used to route connections through the board, freeing up surface area for other components or functions. This is especially advantageous in compact or miniaturized electronic devices where space is limited.

Thermal management

Via holes can aid in thermal management in thick film ceramics. They can be used to transfer heat from one layer of the board to another, helping to dissipate heat generated by components or circuits. This can be particularly important in high-power or high-heat applications, where efficient thermal management is crucial for preventing overheating and ensuring reliable performance.

Mechanical stability

Via holes provide additional support and reinforcement to the board, reducing the risk of warping, bending, or cracking. Via holes can also help improve the overall mechanical integrity of the board by reducing stress concentration points and enhancing its structural rigidity.

Design flexibility

Via holes offer design flexibility in thick film ceramic boards. They can be designed and placed according to the specific requirements of the circuit or system, allowing for customized and optimized designs. Via holes can be used to route traces, create vias for component mounting, or provide grounding or shielding, among other functionalities. This flexibility in design allows for more efficient and effective circuit layouts, which can lead to improved performance and reliability.

As previously mentioned, designing via holes in thick film ceramic boards offers various benefits. However, when it comes to choosing the appropriate paste for via holes, silver paste is often recommended to our customers. But why is that? Can I use gold or copper? In our upcoming article, we will delve into the reasons behind this recommendation and provide you with valuable insights. Stay tuned to uncover the answers!

“TEN Q & A” about Ceramic Printed Circuit Board

Monday, February 27th, 2023

Q1: What do the abbreviations DBC and AMB stand for?

A: DBC means “Direct Bond Copper” while full name of AMB is “Active Metal Brazed”. Both abbreviations refer to bonding technology of attaching a relatively thick copper (generally more than 0.2mm) on the ceramic substrates. These two technologies can be used to fabricate metalized ceramic substrates.

Q2: What is the mainly difference between DBC and AMB?

A: The mainly difference is AMB need to braze the copper to a ceramic board by active metal while DBC can directly connect the copper and substrate without any additional materials.

Q3: Which kind of ceramics are suitable for DBC and AMB?

A: DBC technology is suitable for oxide ceramics such as Al2O3 and ZTA. Non-oxide ceramics must be oxidized before they can be bonded to copper by DBC technology. ALN can be made into DBC or AMB ceramics, but Si3N4 only can be used as AMB substrates.

Q4: What is the function of metalized ceramic PCB?

The metallized ceramic substrate needs to carrier and interconnect multiple power semiconductor devices. The resulting electronic components are called power modules or multi-chip packages, most commonly LED packages or semiconductor packages.

Q5: Does AMB can be used with oxide ceramics?

A: Yes, but the effective of DBC technology is better and the cost is relatively lower.

Q6: What is the most important performance need to be considered when design a new ceramic PCB?

A: It depends on the end application of product will be used in. Ceramics are chemically inert substances that are resistant to corrosion, moisture, and high temperatures, making them preferable to organic dielectrics that degrade in corrosive environments. Electrical, thermal and mechanical properties are equally important in the design of a new substrate. Dielectric strength is an important factor to meet the isolation requirements, which should be set according to the standards, specifications and regulations of the target application. Low thermal conductivity is not conducive to the heat transfer between the chip and the surrounding environment. The bending strength and fracture toughness play an important role in prolonging the service life of the substrate under thermal-mechanical stress.

Q7: How to choose a suitable substrate?

A: First, the heat dissipation of power semiconductor devices should be understood. Then, based on the chip and the ambient temperature, the required substrate thermal resistance is calculated. However, the combination of copper and ceramic may not always achieve the desired thermal resistance. For one thing, the isolation voltage determines the minimum thickness of the ceramic. On the other hand, the thickness ratio of copper to ceramic has a great effect on the reliability. Finally, the set of applicable standards will be very limited.

Q8: Are DBC and AMB substrates suitable for high voltage applications?

A: The DBC substrate is ideal for applications with operating voltages up to 1.7 kV. For higher operating voltages, a thicker ceramic layer is required to meet the relevant isolation requirements. Silicon nitride (ALN) is often used because its high thermal conductivity offsets the increased thickness. In addition, resistance to partial discharge is particularly important in this application. Thus, AMB is superior to DBC techniques for this purpose unless the interfacial gap between copper and ceramics can be eliminated.

Q9: Are DBC and AMB substrates copper plated only on both sides?

A: No, both of two technologies can plate copper only on one side. But this is not a standard combination of materials, however, because the resulting flatness of the substrate is critical in multiple applications.

Q10: What are the shapes of substrates?

A: The rectangle is the cheapest and most common shape to produce. Other shapes are also available, but may incur additional production costs.

What is the DBC Ceramic Copper Oxidation Technology

Monday, February 20th, 2023

DBC (Direct Bond Copper) ceramic PCB also known as DCB ceramic, which is widely used in various type of high-power semiconductor, especially in IGBT package material by means of its excellent electricity and thermal conductivity of copper and the advantages of high mechanical strength and low dielectric loss of ceramics. DBC technology uses the oxygen-containing eutectic solution of copper to directly apply it to the ceramic. The key factor in the preparation process is the introduction of oxygen element, so the copper foil needs to be pre-oxidized in advance. Do you want to know what is the copper foil oxidation technology during the DBC ceramics manufacturing? Hereinbelow, we will introduce the oxidation process for you.

Oxidation technology of copper foil

Copper oxidation is divided into Wet Air Oxidation (including soaking oxidation and spraying oxidation) and Dry Oxidation. Both oxidation methods can form CuO or Cu2O on the surface of copper foil.

Wet Air Oxidation (WAO)

i. Soaking oxidation

First, the copper is pickled with 3% dilute sulfuric acid, and then washed by the spray washing machine after overflow. Next, sent the copper into the mixed solution of potassium permanganate and copper sulfate (the concentration of potassium permanganate is about 31.6mg/L and the copper sulfate is about 95.4mg/L) for soaking and oxidation. The oxidized copper is then washed with water and three-stage countercurrent washing, and then slowly pulled for dehydration and drying (the temperature is about 100℃) to complete soaking and oxidation.

ii. Spraying oxidation

Spraying oxidation is a kind of WAO, only the oxidation method become spraying. Spray oxidation is to spray copper with mixed solution of manganese nitrate and copper nitrate (concentration of about 3%) after pickling and washing. The sprayed copper is dried directly in the tunnel kiln (the temperature is about 200℃). In the drying process of tunnel kiln, the manganese nitrate and copper nitrate sprayed on the copper sheet are decomposed into copper oxide and manganese oxide. The ratio of soaking oxidation and spraying oxidation treatment of copper sheet is about 5:5.

Dry Oxidation

Dry oxidation is very easy to process, put the copper into oxidation oven firstly, then heating up to 600~800^oC for oxidizing around 30mins and then subjected to air cooling annealing.

Wet Air Oxidation VS Dry Oxidation

At present, the existing industry is widely used to finish the high-temperature annealing oxidation of copper then sintering with ceramic substrate, that is dry oxidation. But this high temperature annealing, oxidation in one way has some drawbacks as following:

Uneven oxidation. It will directly cause sintering defects during sintering, and the peeling strength will change greatly.
Leaving conveyor belt marks. Because the high temperature and oxidation process is transported by the conveyor belt, the existence of the conveyor belt mesh will affect the temperature distribution of the entire copper is not uniform, leaving marks/traces of the conveyor belt. The result of sintering is to leave the corresponding trace on the bonding surface of CuAl2O3.
High temperature annealing and oxidation will accompany the grain growth of copper. In the subsequent sintering process, the grain will continue to grow, which brings adverse effects on the mechanical properties and surface treatment of copper. The copper surface grain produced by wet oxidation is fine, which is conducive to improving the mechanical properties of copper and eliminating the traces of conveyor belt. The main difference between wet oxidation and dry oxidation is shown in the bending resistance, heat resistance cycle performance and peeling strength, and these three indicators are significantly better than dry oxidation. Wet oxidation products can better meet the requirements of bending strength and heat resistance cycle performance.

So, this is the end of this post, Best Technology specialized in fabricating ceramic PCB (including DBC, DPC, AMB, HTCC and LTCC technology) for more than 16 years, we have rich engineering team and professional sales team can provide one-stop service for you. Welcome to contact us if you have any inquiries about ceramic PCB.

Everything you should know about Tg in PCB

Wednesday, January 4th, 2023

Working temperature changes can have a significant influence on the operation, reliability, lifetime and quality of products. Temperature rises results in materials expanding, however, the substrate materials that PCB are made of have different thermal expansion coefficients, this causes mechanical stress that can create micro-cracks that may be undetected during electrical tests carried out at the end of production.

Due to the policy of RoHS issued in 2002 required lead-free alloys for soldering. However, removing lead directly results in the rise of melting temperature, printed circuit boards are therefore subject to higher temperatures during soldering (including reflow and wave). Depending on the chosen reflow process (single, double…), it is necessary to use a PCB with appropriate mechanical characteristics, especially one with suitable Tg.

What is Tg?

Tg (glass transition temperature) is the temperature value that guarantees the mechanical stability of the PCB during operational life time of the PCB, it refers to the critical temperature at which the substrate melts from solid to rubberized liquid, we called the Tg point, or melting point for easy to understanding. The higher the Tg point is, the higher the temperature requirement of the board will be when laminated, and high Tg board after laminated will also be hard and brittle, which benefits for next process such as mechanical drilling (if any) and keep better electrical properties during use.

The glass transition temperature is hard to be measured accurately in considerate many of factors, as well as each material have its own molecular structure, therefore, different materials have a different glass transition temperature, and two different materials may have the same Tg value even they have different characteristics, this enable us to have an alternative choice when the needed material is out of stock.

Features of High Tg materials

Better thermal stability
Good resistance to moisture
Lower thermal expansion coefficient
Good chemical resistance than low Tg material
High value of thermal stress resistance
Excellent reliability

Advantages of High Tg PCB

In general, a normal PCB FR4-Tg is 130-140 degrees, the medium Tg is greater than 150-160 degrees, and high Tg is greater than 170 degrees, High FR4-Tg will have better mechanical and chemical resistance to heat and moisture than standard FR4, here are some advantages of high Tg PCB for your reviewing:

Higher stability: It will automatically improve the heat resistance, chemical resistance, moisture resistance, as well as stability of the device if increasing the Tg of a PCB substrate.
Withstand high power density design: If the device has a high power density and a fairly high calorific value, then high Tg PCB will be a good solution for heat management.
Larger printed circuit boards can be used to change the design and power requirements of the equipment while reducing the heat generation of ordinary boards, and high Tg PCBS can also be used.
Ideal choice of multi-layer and HDI PCB: Because multi-layer and HDI PCB are more compact and circuit dense, it will result in a high level of heat dissipation. Therefore, high TG PCBs are commonly used in multi-layer and HDI PCBs to ensure the reliability of PCB manufacturing.

When do you need a High Tg PCB?

Normally to ensure the best performance of a PCB, the maximum operating temperature of the circuit board should be about 20 degrees less than the glass transition temperature. For example, if the Tg value of material is 150 degrees, then the actual operating temperature of this circuit board shouldn’t more than 130 degrees. So, when do you need a high Tg PCB?

If your end application requires to bear a thermal load greater than 25 degrees centigrade below the Tg, then a high Tg PCB is the best choice for your needs.
To make sure the safety when your products require an operating temperature equal or greater than 130 degrees, a high Tg PCB is great for your application.
If your application requires a multi-layer PCB to meet your needs, then a high Tg material is good for the PCB.

Applications that require a high Tg PCB

Gateway
Inverter
Antenna
Wifi Booster
Embedded Systems Development
Embedded Computer Systems
Ac Power Supplies
RF device
LED industry

Best Tech has rich experience in manufacturing High Tg PCB, we can make PCBs from Tg170 to maximum Tg260, meanwhile, if your application need to use under extremely high temperature like 800C, you’d better use Ceramic board which can go through -55~880C.

Suitable Choice of Ceramic Substrate for Your Application

Wednesday, December 7th, 2022

With the rapid development of ceramic industry, Ceramic Circuit Board is widely used in semi-conductors and electronic packages fields because it provides an excellent electric conductivity, low thermal expansion and good insulation properties over standard FR4 based PCBs. As you can see from our website: https://www.bestpcbs.com/products/ceramic-substrate.htm, there are various kinds of ceramic substrate materials in the market, different materials have different functions and properties. Here we illustrated the different kinds of materials in the market as below for you to choose which one is ideal for your designs when needs come out.

Common ceramic substrate materials

Nowadays, the most commonly material in the market is oxidation material, it always used in automobile products as its wear resistance and good strength.

Besides, there are some nitrides and silicious can be used in high power products.

For a quick look, here I listed as following:

Alumina Oxide (Al2O3)
Alumina Nitride (ALN)
Beryllium Oxide (BeO)
Silicon Nitride (Si3N4)
Zirconium Oxide (ZrO2)
Silicon Carbide (SiC)

Characteristics of different substrate materials

Alumina Oxide (Al2O3)

Alumina substrate characterize as a pure white substrate and the most commonly used ceramic substrate material in the electronics industry because of its high strength and chemical stability compared to most other oxide ceramics in terms of mechanical, thermal and electrical properties, and the richful source of raw materials is suitable for a variety of technical manufacturing and different shapes. The most commonly used Alumina Oxide are 96% alumina and 99.6% alumina.

96% alumina can be used to fabricate Thick Film Ceramic Circuits as it has excellent electrical insulation, mechanical strength, good thermal conductivity, chemical durability and dimensional stability. The surface roughness is generally 0.2~0.6μm, and the maximum using temperature of the substrate can reach 1600℃
99.6% alumina is the mainstay of most Thin-film electronic substrate applications, commonly used in circuit generation for sputtering, evaporation and chemical vapor deposition of metals. 99.6% alumina has higher purity, smaller grain size, and excellent surface smoothness than 96% alumina (the surface roughness is generally 0.08~0.1μm), and it can withstand maximum 1700°C temperature when applied in applications.

Alumina Nitride (ALN)

Currently, Alumina Nitride won the high attention of the public by means of two key excellent properties: one is high thermal conductivity. Alumina nitride offers a big increasing in thermal conductivity (170Wm.k), which is approximately 100-200 times than FR4 substrates did, while alumina oxide only offers 24W/m.K.

Another characteristic is silicon-matched expansion coefficient of 4.7ppm/°C 20~300°C, this makes it suitable for used in extremely harsh environments likely in high temperatures. The disadvantage is that even an extra thin oxidation will affect the thermal conductivity. Only by strictly controlling the material and process, can aluminum nitride substrate be produced with good consistency. That’s why the alumina nitride is expansive than alumina oxide.

By visually, alumina nitride has an off-white color, that give us a chance to distinguish it with alumina oxide easily.

Beryllium Oxide (BeO)

Beryllium Oxide has a high thermal conductivity than alumina, therefore, it almost used where high thermal conductivity required. But when the temperature exceeds 300°C, it drops quickly. It is not as widely used as alumina oxide or aluminum nitride, the most important thing is that its toxicity limits its development.

Silicon Nitride (Si3N4)

Silicon Nitride is a material with high fracture toughness and strong heat resistance are often used as alternative materials for modules in recent years. With strong mechanical, high temperature resistance, corrosion resistance and wear resistance, it is widely used in automotive shock absorber, engine, especially automotive IGBT products, as well as traffic track, aerospace and other fields.

Zirconium Oxide (ZrO2)

Zirconium Oxide is popular as its exceptional strength, toughness, biocompatibility, high fatigue and wear resistance (15times of alumina oxide) render it optimal for dental applications.

Silicon Carbide (SiC)

The essence of silicon carbide ceramic substrate is a silicon material, which determines its high current density characteristics due to its superior thermal conductivity.

In the meantime, the higher band gap width determines the higher breakdown field and higher operating temperature of silicon carbide (SiC) ceramic circuit board.

The core advantages of silicon carbide are high temperature resistance, high pressure resistance, wear resistance, low loss and high frequency work. Therefore, it is used for products with high heat dissipation, high thermal conductivity, large current, large voltage and high frequency operation.

Send us inquiry for fabrication

At present, you should have a brief acknowledge about different ceramic substrate materials and their characteristics, and you should be able to decide which materials is most suitable for you. If you still have some concerns or different opinions about substrate for Ceramic pcb, welcome to contact us, Best Tech will offer you free advice and technical support for ceramic substrate choice.

Why ENEPIG More Suitable for Ceramic PCB Wire Bonding?

Thursday, October 20th, 2022

There are many surface treatment choices that can be used on Ceramic PCB, but why ENEPIG is one of options we always recommend to our customers whom have wire bonding demands?

In the application of Ceramic PCB, COB or wire bonding was widely used for the packaging technology in thin, short, high speed of electronic products. The Chip On Board (COB) technology refers to a technology in which bare chips are directly attached to the PCB board and then connected electronically through metal wires, namely “Wire Bonding”. Due to gold wire has an excellent electrical conductivity, thermal conductivity, corrosion and oxidation resistance, gold wire is often used as a main bonding material in microelectronics packaging.

What is ENEPIG?

ENEPIG, is a type of surface treatment on Printed Circuit Boards and ceramic PCB, the full name of it is Electroless Nickel – Electroless Palladium – Immersion Gold, now it is widely used in wire bonding field.

How does it work and what’s the standard thickness of each layer?

Electroless Nickel: Nickel acts as a barrier layer, preventing copper from interacting with the other metals involved in this plating technology, particularly gold. The layer is deposited on the catalytic copper surface using an oxidation-reduction reaction. The result is a layer that is between 2.0 to 5.0 microns thick.
Electroless Palladium: Palladium is a relatively stable metal at room temperature, and it is difficult to be oxidized within 400℃. The chemically deposited palladium layer has a neat lattice arrangement, uniform grain size and compact structure. Adding palladium layer between nickel layer and gold layer can effectively prevent the diffusion of nickel layer to gold layer. The Palladium is a layer with a thickness between 0.03 to 0.10 microns, it also depends on the final applications.
Immersion Gold: The main function of the gold layer is to bond with the gold wire. If there is no palladium layer as a diffusion barrier between the nickel layer and the gold layer, the gold layer can also bond with the gold wire after reflow, as long as the gold layer reaches a certain thickness. For example, when the thickness of the electroplated nickel gold reaches 0.3um, it can bond with the gold wire. In addition, gold itself has a good bonding ability with gold wire, and in ENEPIG process, due to the palladium layer protects the gold layer from the pollution of nickel, only a thin gold layer (0.03um~0.05umm) is needed to have a good bonding property. This’s why there’s cost advantage of ENEPIG than that of thicker ENIG.

Why choose ENEPIG?

ENIPIG has a good wiring bonding ability, solder joint reliability, multiple reflow soldering and excellent storage time, can correspond to and meet the requirements of a variety of different assemblies. Below is a comparison about performance of different surface treatments:

(Comparison-about-performance-of-different-surface-treatments)

Advantages of ENEPIG

“Black Nickel” free — The palladium layer separates the Nickel layer from the gold layer, it can prevents the mutual migration of gold and nickel, so no black nickel will appear

Excellent gold wire bondability — the gold plating/coating is very thin, can be used for gold wire bonding as well aluminum wire bonding

Palladium acts as an additional barrier layer to further reduce copper diffusion to surface, thus ensuring good solderability

Cost-effective than ENIG

Lead-free nickel

Good compatibility between coating and solder paste

Very suitable for packaging components such as SSOP, TSOP, QFP, TQFP, PBGA

Best Technology is a 16+ years PCB manufacturer and we made many ENEPIG PCBs and ceramic PCBs for our customers, welcome to contact us if you have demands on ENEPIG PCB.

Archive for the ‘Ceramic PCB’ Category

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