High-Temperature Deformation Characteristics of Cu<sub>3</sub>Sn Evaluated by the Tests Using Composite Copper Wire Specimen.

Abstract

In recent years, the propulsive movement of electrification of automobiles and airplanes is accelerating to realize a decarbonized society. Along with this movement, lightening of electric mobility is also required to reduce electricity consumption. The power modules used in electric mobility control high voltage and great current and are subjected to high temperature. Since most of the power modules employ Si semiconductor chips which can’t work in such a high-temperature range, cooling systems must be installed to prevent their failure. Therefore, next-generation power semiconductor chips using SiC or GaN, which can work properly in a high-temperature environment of over 200 ℃, are expected to be mounted in power modules to lighten them by eliminating cooling system. Cu3Sn intermetallic bonding technique which can form joints having a high melting point has attracted attention to achieve the mounting of the chips. To put the technique into practical use, the high-temperature deformation characteristics of Cu3Sn must be clarified. We previously proposed a materials testing method using a composite copper wire (CCW) specimen having a Cu3Sn layer to estimate the tensile characteristics of Cu3Sn. In this study, we conducted tensile tests, tension-strain maintenance tests, and cyclic tension-compression loading tests using the CCW specimen to evaluate the deformation characteristics of Cu3Sn in the temperature range between room temperature and 200 ℃.