红外焦平面探测器封装结构热应力分析

摘要

Infrared focal plane array detector has a multilayer configuration which is mainly composed of electrical lead board,Si-ROIC,indium bumps and detector chip. Substantial thermal stress is generated in the IRFPA packaging as-sembly at cryogenic temperature due to the difference in coefficient of thermal expansion(CTE)of various materials in the assembly,which affects the thermal cycling reliability significantly. A finite element analysis model for investiga-tion of thermal stress distribution in detector at cryogenic temperature is established. This model is utilized to analyze the influence of CTE,Young′s modulus and thickness of electrical lead board on thermal stress and warpage for Si and CdZnTe substrate detectors;Some improved methods are presented respectively according to the analytical results for two kinds of detectors,and these methods are verified by calculation.%红外焦平面探测器是一个主要由引线基板、硅读出电路、铟柱和探测器芯片组成的多层结构。由于材料层间热膨胀系数的差异，低温时探测器中会产生相当大的热应力，对探测器温度循环可靠性影响严重。为了考察红外焦平面探测器低温下的热应力情况，建立了探测器结构的有限元分析模型；利用该模型分析了引线基板热膨胀系数、弹性模量，及其厚度分别对Si、CdZnTe衬底类型的探测器热失配应力和形变的影响；根据对这两种类型探测器的分析结果，分别提出了相应的改进方法，并对方法进行了计算验证。