Thermal stress is a common problem as for the cryogenic IRFPA (Infrared Focal Plane Array) Assembly, especially when the assembly is in large scale. The stress is generated when the assembly enduring times of temperature cycling ranging from 80K to 300K approximately. This huge temperature change and the mismatch of the CTE (coefficient of thermal expansion) between these materials by which the assembly is made results in severe thermal stress in the IRFPA. This thermal stress is the main reason for the failure of assembly during temperature cycling such as the degradation of device performance and even the die crack. To improve the reliability of the FPA assembly reducing the thermal stress becomes a more important issue. This article presents several results of the analysis of the thermal stress of IRFPA assembly using FEM (Finite Element Method). According to this result we have got an optimal design of the assembly structure.

Date Published: 8 January 2008
PDF: 5 pages
Proc. SPIE 6835, Infrared Materials, Devices, and Applications, 68350J (8 January 2008); doi: 10.1117/12.757438

Published in SPIE Proceedings Vol. 6835:
Infrared Materials, Devices, and Applications
Yi Cai; Haimei Gong; Jean-Pierre Chatard, Editor(s)