What's good about ceramic PCB circuit boards?

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Brenda 0 2023-11-24 TOPIC

What's good about ceramic PCB circuit boards?

1. Why do we use Chinese ceramic circuit board

Common printed circuit boards are usually made of copper foil bonded with the substrate, 1oz vs 2oz and the substrate material is mainly glass fiber (FR-4), phenolic resin (FR-3) and other materials, and the adhesive is usually phenolic, epoxy and so on. Due to thermal stress, chemical factors, improper manufacturing process or copper asymmetry in the design process, it is easy to cause different degrees of warping of the PCB board.

Another PCB substrate - ceramic substrate, because of its heat dissipation, how to test a circuit board with a multimeter flow carrying, insulation, thermal expansion coefficient and other performance is much better than ordinary glass fiber PCB, so widely used in high-power power electronic modules, aerospace, military electronics and other products.

The copper foil is bonded to the substrate with an adhesive using an ordinary PCB. Ceramic PCBS are combined with copper foils and ceramic substrates at high temperatures. Strong binding force, copper foil will not fall off, high reliability, stable performance in high temperature and high humidity environment.

2. The main material of ceramic substrate

Alumina (Al2O3)

Alumina is the most important and commonly used substrate material in ceramic substrate, because in mechanical, thermal and electrical properties research compared to most other metal oxide ceramics, the strength and chemical structure stability is high, and the main source of raw materials can be rich, suitable for the development of manufacturing capacity through various forms of technology and different shapes of society. According to the percentage of alumina (Al2O3) can be divided into: 75 porcelain, 96 porcelain, 99.5 porcelain. The amount of alumina is different, and its electrical properties are almost not affected, but its mechanical properties and thermal conductivity are greatly affected. There is more glass in the substrate with low purity, and the surface roughness is large. The higher the purity of the substrate, the cleaner and denser, the lower the dielectric propagation loss, but the higher the price.

Beryllium oxide (BeO)

It has a higher thermal conductivity than aluminum and can be used in situations where high thermal conductivity is required.

Aluminum nitride (AlN)

Aluminum nitride ceramics are ceramics with aluminum nitride powder as the main crystalline phase. Compared with alumina ceramic substrate, it has higher insulation resistance and insulation voltage resistance, and lower dielectric constant. Its thermal conductivity is 7 to 10 times that of Al2O3, and the coefficient of thermal expansion (CTE) is approximately matched with silicon wafers, which is very important for high-power semiconductor chips. In the production process, the thermal conductivity of AlN is greatly affected by the content of residual oxygen impurities. Reducing oxygen content can significantly increase thermal conductivity. At present, the thermal conductivity at the production level of 170 Wu002F(m k) is not a problem.

It can be seen that alumina ceramics play a dominant role in microelectronics, power electronics, hybrid microelectronics and power modules with their superior comprehensive properties.

Compared with the ceramic substrate price of different materials of the same size (100mm×100mm×1mm) on the market :96% alumina 9.5 yuan, 99% alumina 18 yuan, aluminum nitride 150 yuan, beryllium oxide 650 yuan, it can be seen that the price gap between different substrates is also relatively large.

3. Advantages and disadvantages of ceramic PCB

advantage

100A current continuously passes through 1 mm 0.3mm thick copper body, and the temperature rises about 17 °C; 100A current is continuously passed through the copper body of 2 mm 0.3mm thick, and the temperature rises about 5 °C

Better heat dissipation, lower coefficient of thermal expansion, more stable shape, less deformation and warping.

Good insulation, high pressure resistance, to ensure personal and equipment safety.

Strong bonding force, using bonding technology, the surface of copper foil will not fall off.

High reliability, high temperature, high humidity environment stable performance

shortcoming

Fragile, which is one of the main disadvantages, resulting in the production of only a small area of the board.

The price is expensive, the requirements for electronic products are getting higher and higher, ceramic circuit boards are also used in some high-end products, low-end products will not be used.

4. The use of ceramic PCB

High power electronics module, solar panel module, etc.

High-frequency electronic switches control power supplies and solid-state relays

Automotive electronics, aerospace, military electronics

High-power LED lighting products

Communication antenna, car igniter

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