【Introduction】

      At present, methods that can be used for high-melting point soldering of high-power chips mainly include high-temperature lead-free solder, nanoparticle sintering method and transient liquid phase method. The high-temperature lead-free solder is mainly Sn-Au solder, which has a higher melting point and better strength and conductivity, but the application cost of Au element is higher, and the Au-based alloy has high hardness and poor workability, which is not suitable for large-scale Promote use. The nanoparticle sintering method mainly uses Ag nanoparticles, but the preparation process of Ag nanoparticles is more complicated, and the large pressure required during sintering makes it should be subject to many restrictions. The transient liquid phase method (TLP) has a simple process, designing a suitable composition ratio on the basis of the Sn-based solder, and obtaining an intermetallic compound with a high melting point at a lower temperature. The traditional transient liquid phase method takes a long time to obtain a full-compound solder joint structure. After the introduction of ultrasonic assistance, the time of the chemical reaction can be greatly shortened, and a high melting point solder joint with better mechanical properties can be obtained.

【Innovation Results】

      The use of Sn-based metal particles to mix and prepare the solder paste for SiC chip bonding has a simple process and low cost. And using the method of ultrasonic-assisted reflow, the SiC chip and the pad can be connected in a short time of about 10s. The solder joints have a melting point higher than 400°C and can be used under high temperature conditions to meet the requirements of third-generation semiconductor interconnect solder joints.

       The research content has won 2 national invention patents.

【Scope of application】

      The bonding of third-generation semiconductor chips such as SiC, GaN and InP, as well as high-power devices, can be applied to industries such as automotive electronics and IGBT packaging.

【Person in charge of results】

      Ji Hongjun