InSb红外焦平面探测器结构应力的ANSYS分析

STRESS IN InSb INFRARED FOCAL PLANE ARRAY DETECTOR ANALYZED WITH ANSYS

借助有限元软件系统分析了铟柱取不同直径时红外探测器整体结构的应力分布.模拟结果表明,在固定铟柱高度的前提下,当铟柱直径以2μm的步长从36μm减小到18μm的过程中,InSb芯片上的最大应力值呈现出先减小,后线性增加的趋势,但铟柱上应力最大值始终保持在15.7MPa左右,且分布几乎不变.S i读出电路上的应力小于InSb芯片上的应力值,变化趋势类同于InSb芯片上应力的变化趋势.铟柱直径取30μm时,InSb芯片和S i读出电路上的应力均达到最小值260MPa和140MPa,整个器件的应力分布在接触区呈现明显的集中性、均匀性,分布更合理.

Based on viscoplastic Anand model,von Mises stress distribution of the infrared focal plane array detector is analyzed by finite element method.Simulation results show that as the diameters of the indium bump decreases from 36μm to 18μm in step of 2μm,the maximum stress existing in InSb chip reduces at first,then increases linearly with indium bump diameters.Yet the stress distribution in the indium bump is almost unchangeable and its maximum value keeps at 15.7MPa.Furthermore the maximum stress in Si-CMOS readout integrated circuit is smaller than that of InSb chip,and its changing tendency chart is almost the same as that of InSb chip.When the diameter of the indium bump is set to 30μm,the maximum stresses existing in both InSb chip and Si CMOS readout integrated circuit reach the minimal value 260MPa and 140MPa,respectively.Simulations also show that the stress distribution at the contact areas is uniform and concentrated,the stress value in the whole infrared focal plane array detector is smallest,and its distribution is promising.