Nondestructive evaluation of the delamination of fine bumps in three-dimensionally stacked flip chip structures

A new nondestructive evaluation method for detecting delamination between a chip and metallic bumps in area-arrayed flip chip structures has been developed by measuring the local surface deformation of a chip, which is caused by the mismatch in mechanical properties between the metallic bumps and underfill. The change of the local deformation was measured by using a high resolution laser displacement meter and it was confirmed that the 3 μm-thick delamination can be detected easily using the proposed method.