A Void Free Soldering Process in Large-Area, High Power Insulated Gate Bipolar Transistor Modules

• Published in: Japanese Journal of Applied Physics Vol. 40; no. 6R; p. 3985
• Main Authors: Onuki, Jin, Chonan, Yasunori, Komiyama, Takao, Nihei, Masayasu, Saitou, Ryuuichi, Suwa, Masateru, Morita, Toshiaki
• Format: Journal Article
• Language: English
• Published: 01.06.2001
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.40.3985

We have developed a new void free process for making the solder joint between the chip mounted AlN substrate and the metal substrate in large-area, high power insulated gate bipolar transistor (IGBT) modules. This new process consists of two steps. First, Ar + were used to clean the surfaces of Ni plated film on a metal and AlN substrates which were then coated with 0.5-µm-thick Ag film. Second, 50 wt% Pb–Sn solder was sandwiched between the two substrates and heated to 503 K in a vacuum for 5 min before being cooled in a N 2 atmosphere. By using this process, the area percentage of voids in a soldering area up to 130×190 mm 2 can be reduced to less than 0.1%. IGBT modules made by this process were also found to exhibit satisfactory current-voltage characteristics.