CuSn/InAu μ-bump induced local deformation and mechanical stress in high-density 3D-LSI

摘要

Reliability issues such as local deformation and locally induced mechanical stress in the high-density 3D-LSIs byμ -bumps were investigated using the optical interferometer and the micro-Raman spectroscopy. It has been observed that the degree of local deformation in 3D-LSI increases with the increase in the bump spacing and decreases with the increase in the wafer thickness. Whereas the mechanical stress due to local deformation depends not only on the wafer thickness and μ-bump layout dimensions, but also with the surface morphology of the back-ground ultra-thin wafer.