Производство и применение керамических печатных платОпубликовано 2020-03-03
Производство и применение керамических печатных плат
Ceramic substrate refers to a special process board where copper foil is directly bonded to the surface (single-sided or double-sided) of alumina (Al2O3) or aluminum nitride (AlN) ceramic substrate at high temperature. The manufactured ultra-thin composite substrate has excellent electrical insulation properties, high thermal conductivity, excellent solderability and high adhesion strength, and can etch out various patterns like a PCB board, and has a large current carrying capacity. ability. Therefore, ceramic substrates have become the basic materials for high-power power electronic circuit structure technology and interconnection technology.
Features: strong mechanical stress, stable shape; high strength, high thermal conductivity, high insulation; strong binding force, anti-corrosion.
Good thermal cycling performance, with 50,000 cycles, high reliability.
Like PCB board (or IMS substrate), it can etch a variety of graphic structures; no pollution, no pollution.
The operating temperature is wide -55 ℃ ～ 850 ℃; the thermal expansion coefficient is close to silicon, which simplifies the production process of power modules.
At this stage, there are five types of ceramic heat sink substrates: HTCC, LTCC, DBC, DPC, and LAM. HTCC \ LTCC all belong to the sintering process and the cost will be higher.
However, DBC and DPC are developed in China in recent years and are professional technologies for energy production. DBC uses high temperature heating to combine Al2O3 and Cu plates. The technical bottleneck is that it is difficult to solve the problem of micro pores between Al2O3 and Cu plates This makes the product’s mass production energy and yield rate more challenging, while DPC technology uses direct copper plating technology to deposit Cu on the Al2O3 substrate. Its process combines materials with thin film process technology. Its products are The most commonly used ceramic heat sink substrate in recent years. However, its ability to integrate material control and process technology is relatively high, which makes the technical threshold for entering the DPC industry and stable production relatively high. LAM technology is also known as laser rapid activation metallization technology.
1.HTCC (High-Temperature Co-fired Ceramic)
HTCC is also called high-temperature co-fired multilayer ceramic. The manufacturing process is very similar to LTCC. The main difference is that HTCC ceramic powder is not added with glass material. Therefore, HTCC must be dried and hardened at a high temperature of 1300 ~ 1600 ℃. The green embryo is then drilled with vias, and the holes and printed circuits are filled with screen printing technology. Due to the high co-firing temperature, the choice of metal conductor materials is limited. The main material is a high melting point but conductive However, metals with poor properties such as tungsten, molybdenum, manganese, etc. are finally laminated and sintered.
2.LTCC (Low-Temperature Co-fired Ceramic)
LTCC is also known as low-temperature co-fired multilayer ceramic substrate. This technology must first add inorganic alumina powder and about 30% to 50% of glass material plus organic binder to make it evenly mixed into a slurry, and then The scraper is used to scrape the slurry into a sheet shape, and then the sheet slurry is formed into a thin piece of green embryo through a drying process, and then a through hole is drilled according to the design of each layer as the signal transmission of each layer. LTCC internal circuit The screen printing technology is used to fill holes and printed circuits on the raw embryos. The internal and external electrodes can be made of silver, copper, gold and other metals. Finally, the layers are laminated and placed at 850 ~ 900 ° C. Sintering in a sintering furnace can be completed.
3.DBC (Direct Bonded Copper)
Direct copper deposition technology uses copper’s oxygen-containing eutectic solution to directly apply copper to ceramics. The basic principle is to introduce an appropriate amount of oxygen between copper and ceramics before or during the bonding process, at 1065 ℃ ~ 1083. In the range of ℃, copper and oxygen form a Cu-O eutectic liquid. DBC technology uses this eutectic liquid to react with the ceramic substrate to generate CuAlO2 or CuAl2O4 phase on the one hand, and infiltrate the copper foil to achieve the combination of the ceramic substrate and the copper plate.
DPC production process of alumina and aluminum nitride ceramic substrates.