Formation mechanism of Cu/Cu3Sn–Cu/Cu interconnections based on solder-filled microporous copper as interlayer via a current-assisted thermal compression bonding

Abstract

In this study, a Cu/Cu3Sn–Cu/Cu interconnection can be achieved based on solder-filled microporous copper (MPC) as interlayer via a current-assisted thermal compression bonding. The high-temperature soldering connection materials can be used in the third-generation semiconductor packaging, so as to meet the promising application in high-temperature power device packaging. The influence of auxiliary current on the microstructure evolution of Cu–Sn IMCs and its formation mechanism were studied. Experiments show that the action of Joule heat coupled with the electron wind significantly enhanced the interfacial reaction at the Cu/Sn metallization interface. The microstructure of Cu6Sn5 changed from scallop-like into columnar due to constitutional supercooling, and the dispersion distribution of Cu6Sn5 also changed. The growth constitutive equations of Cu3Sn in bondlines were established under current-assisted thermal compression bonding process.