The Investigation of Bonding Reliability Improvement for Power Module Containing Sintered Ag

Abstract

Sintered bonding using Ag particles is one of the bonding materials that enables high-temperature operation of power modules. This bonding has begun to be applied as a die bonding material under SiC chip for getting both low heat resistance and high heat dissipation. This research report focuses on the effect of voids in the sintered Ag layer on bonding reliability. The void geometry observed with SEM(Scanning Electron Microscope) and EBSD(Electron Back Scatter Diffraction). The mechanical properties of each void ratio were got by tensile test and stress relaxation test, and compared with the bonding reliability. As a result, it was found that the dense sintered Ag layer is superior to the sparse sintered Ag layer in terms of bonding reliability, because the shear strain and creep strain of the dense sintered Ag layer are suppressed in heat cycle test. Furthermore, comparing shear Strain and creep strain, it was found that creep strain is the dominant factor in bonding reliability in heat cycle test.