Deformation Analysis of 128×128 Infrared Detector with Reticulated InSb Pixel Array

Abstract

The reticulated InSb pixel array was successfully employed in the design of large format InSb infrared focal plane arrays (IRFPAs) detector, to remove the thermal strain accumulated in InSb IRFPAs with the thermal shock test. In order to explore the deformation rules in the InSb IRFPAs with reticulated InSb pixel array, in light of the proposed equivalent modeling, a three-dimensional modeling of InSb IRFPAs is created, and the Z-component of strain is selected to compare the displacements in the various layers of InSb IRFPAs. Analyzing results that show the top surface deformation of InSb IRFPAs originates from the thermal mismatch between the silicon readout integrated circuit (ROIC) and the indium bump array directly above. After passing through the intermediate layer and the silicon substrate, the deformation amplitude along Z-direction is reduced firstly from 0.113 μm to 0.0395 μm, finally to 0.0042 μm. Here the intermediate layer is made up of the indium bump array and the reticulated InSb pixel array. These deformation data suggest that the InSb IRFPAs with reticulated InSb pixel array is superior to that designed with the underfill filled structure in the fabricating large format InSb IRFPAs.