关键词: IPM封装, 双面覆铜陶瓷基板, 变色

Abstract: Intelligent power module (IPM) packages are often in the form of exposed heat sinks to improve the efficiency of heat exchange with the external environment. The heat sinks are usually made of frames or substrates with high thermal conductivity (such as double-sided direct bond copper ceramic substrates). Due to the structural characteristics of the ceramic substrates, the copper layer exposed on the outer side of the substrate of plastic package is not covered by the tin layer during tin plating process, therefore the surface discoloration problem can occur. The discoloration phenomenon of the heat sinks of IPM modules with double-sided direct bond copper ceramic substrates is analyzed, and the treatment method of discoloration, preventive measures and their respective advantages and disadvantages are summarized. The research results show that combining treatment and prevention methods in the package process design can effectively solve the discoloration problem of heat sinks of double-sided direct bond copper ceramic substrates in IPM package.

Key words: IPM package, double-sided direct bond copper ceramic substrate, discoloration