AMB AlN ceramic substrate

Aluminum nitride (AlN) ceramics as a high thermal conductivity, thermal expansion coefficient close to silicon semiconductor material, has good insulation and mechanical properties, aluminum nitride copper clad plate has very high thermal conductivity in thermal characteristics, heat dissipation fast; In terms of stress, the thermal expansion coefficient is close to silicon, and the internal stress of the whole module is low, which improves the reliability of IGBT module.  These excellent properties make aluminum nitride copper clad plate the first choice for high pressure IGBT module packaging.  AMB substrate is bonded by chemical reaction between ceramic and active metal solder paste at high temperature, so its bonding strength is higher and reliability is better. 

Specification

Highlight

Advantages of aluminum nitride ceramic AMB copper clad plate:  

1) The ceramic part has excellent thermal conductivity and pressure resistance;  

2) The copper conductor part has a very high current carrying capacity;  

3) High adhesion strength and reliability between metal and ceramics;  

4) Easy to etch the graph, forming the circuit board;  

5) Excellent welding performance, suitable for aluminum wire bonding.  

Solution

We are able to prepare AMB AlN ceramic substrate with excellent performance through the following process.  

1. High performance aluminum nitride ceramic substrate is prepared by flow casting technology, which has high mechanical strength and high thermal conductivity;  

2. The key technology to solve the AMB technology of aluminum nitride ceramics and copper foil welding is brazing solder. In order to achieve a more solid and reliable welding of copper and aluminum nitride ceramics in the welding process, I use a special silver copper titanium brazing solder, combined with printing and other technological means to achieve the coating of solder, and strictly control the sintering temperature of brazing. 

Challenge

In the process of preparing excellent AMB AlN ceramic substrate, we may encounter several difficult problems.  

1. After AlN is sintered, the finer the grain, the larger the area of grain boundary and the more zigzag the grain boundary are, the less conducive to the expansion of brittle crack. At the same time, the finer the grain, the fewer defects and pores, so the substrate strength is higher.  To solve this problem, the sintering temperature of AlN substrate should be strictly controlled. 

2. In the application of aluminum nitride copper clad plate, the interface combination between AlN and Cu is very important, and the interface phase determines the bonding force between ceramic and metal copper layer.  The silver copper titanium brazing technology adopted by our company can realize the effective combination of copper and aluminum nitride substrate, with fewer holes and high reliability. 

Result

AMB ceramic substrate has higher bonding strength and thermal cycling characteristics.  At present, with the rapid development of power electronics technology, the control module of high-power devices on high-speed rail has a huge demand for the key material of IGBT module encapsulation -- ceramic copper clad plate, especially THE AMB substrate has gradually become the mainstream application.  Our company adopts active metal welding process to prepare silicon nitride ceramic copper clad substrate, which can withstand 500 temperature cycles (-40~155℃) and can carry current greater than 300 A. It has been used in electric vehicles, aerospace and other fields.  In particular, the product adopts active metal welding process to bond multilayer oxygen-free copper to silicon nitride ceramics, and adopts copper column welding to realize vertical interconnection, which has a good promotion effect on IGBT module miniaturization and high reliability.  In addition, IN wind, solar, heat pump, hydropower, biomass energy, green building, new energy equipment, electric vehicles, rail transit and other important fields, AMB substrate has also begun to get more and more applications.