红外焦平面探测器热应力的有限元仿真方法分析

Analysis on finite element method of thermal stress for infrared focal plane detector

以64×64红外焦平面探测器为例,构建了包含探测器芯片、铟柱、填充胶和读出电路的全尺寸有限元仿真模型,与探测器芯片、填充层和读出电路的简化模型进行对比。研究表明,两种模型在芯片热应力的变化趋势上保持一致。由于铟材料与碲镉汞材料之间的热膨胀系数相差较大,随着芯片尺寸的增大,铟柱的影响逐渐增加,填充层简化模型计算得到的芯片热应力与全尺寸模型的热应力的差距会越来越大。

A full-scale simulation model of 64×64 infrared focal plane detector was established in this paper,which includes chip,indium bumps,underfill and readout circuit,to compare with a simplified simulation model including chip,mixed underfill layer and readout circuit.Results show that the two models are consistent in the trend of chip thermal stress within a certain range.As the thermal expansion coefficients of indium and HgCdTe are quite different,the effect of indium bumps increases with the increase of chip size,and the gap of chip thermal stress between the simplified model and full-scale model will also be larger and larger.