隔离槽深度对面阵探测器热应力影响研究

热冲击下InSb面阵探测器的成品率制约着其适用性。为了解光敏元隔离槽深度对InSb芯片中热应力的影响,针对典型器件结构,借助ANSYS软件,分析了隔离槽深度对InSb芯片、底充胶和硅读出电路中Von Mises应力的影响。模拟结果表明:随着隔离槽深度的增加,InSb芯片上的热应力起初缓慢增加,之后增加速度越来越快,当隔离槽深度超过8μm后,InSb芯片上的热应力陡峭上升。对硅读出电路和底充胶来说,在热冲击下累积的热应力似乎与隔离槽深度无关,分别在370 MPa和190 MPa左右浮动。当隔离槽深度取4μm时,整个器件的热应力较小、且分布均匀,能够满足光学串扰及结构可靠性设计的需求。

Effects of Isolation Trough Depth on Infrared Focal Plane Array Detector Structural Stress

Higher fracture probability, appearing in InSb infrared focal plane array （IRFPA） detec- tor under thermal shock loadings, limits its suitability. To learn the effects from photosensitive cells isola- tion trough depth to the InSb infrared focal plane array detector structural stress, for a typical InSb IRFPA structure with underfill, here ANSYS, is employed to research the impacts from isolation trough depths on both Von Mises stress and its distribution. Simulation results show that as the isolation trough depth in- creases from 0 μm to 10 μm in step of 2 μm, the maximal Von Mises stress in the InSb chip first increa- ses slowly, then accelerates fast, once the isolation trough depth is over 8 μm, the maximal Von Mises stress augments steeply, yet for both Si-ROIC and underfill, the thermal stress accumulated in the thermal shock test seems have noting to do with the isolation trough depths, and fluctuates 370 MPa and 190 MPa, respectively. When the isolation trough depth is set at 4 μm, the thermal stress is uniform and small, which can satisfy the need from photo cross talk and structural reliability.