Structural Stress Analysis of 16x16 InSb Infrared Focal Plane Array with Underfill

To reduce the fracture probability of InSb infrared detector in thermal shock from room temperature to 77K, for 16x16 mesa structure InSb infrared focal plane array detector with underfill, here ANSYS, is employed to research the impacts from both indium bump diameters and heights on both Von Mises stress and its distribution. Simulation results show that when the diameters of indium bump increases from 20 mu m to 36 mu m in step of 4 mu m, the maximal Von Mises stress in the InSb chip increases slowly. Besides, when the height of indium bump increases from 8 mu m to 24 mu m in step of 8 mu m, the maximal Von Mises stress in the InSb chip reduces from 1200MPa to 1030MPa. Von Mises stress of Si readout integrated circuits is also much smaller than that of InSb chip.