Negative electrode structure design in InSb focal plane array detector for deformation reduction

Abstract

When an indium antimonide (InSb) infrared focal plane array (IRFPA) is subjected to a thermal shock test, most of the cracks originate from the region over the negative electrode, which restricts its final yield. In light of the proposed equivalent modeling, three negative electrode structures are assessed to eliminate the accumulated deformation around the negative electrode. Simulation results show that when a thicker indium bump array is connected directly with negative InSb material, the accumulated thermal deformation is the minimum, the top surface of InSb chip is the smoothest, and the square checkerboard buckling pattern, present clearly in both gold buffer layer and sparse thicker indium bump array structure, seems to be unclear. All these mean that a thicker indium bump array structure is a good choice, which will benefit to reduce fracture probability of InSb IRFPAs under thermal shock.