背减薄过程中面阵探测器形变研究

Deformation Study on Infrared Focal Plane Array Detector in Back-Thinning Process

为提高Insb面阵探测器的探测率,需要借助背减薄工序把Insb光敏元芯片从300tzm减薄到10μm,这一过程通常决定了面阵探测器的成品率。为了解面阵探测器在背减薄工序中的形变规律,针对典型器件结构,借助ANSYS软件,基于等效建模思路,建立了适用于Insb面阵探测器的三维结构模型,调整Insb光敏元芯片厚度,模拟探测器形变特征及分布随背减薄工艺实施过程的变化规律。模拟结果表明:当InSb光敏元芯片较厚时,面阵探测器的整体形变以弯曲变形为主,其中心区域上凸明显;随着InSb光敏元芯片逐步减薄,其中心区域的上凸变形逐步弱化,当InSb光敏元芯片厚度减薄到12μm时,探测器上表面屈曲变形占优,且随着Insb光敏元芯片厚度的减小而愈加清晰可见,此时探测器整体弯曲变形很弱。

To improve the detectivity of InSb infrared focal plane arrays （IRFPAs）,the thickness of InSb photosensitive chip is usually thinned from 300 μ m to 10 μ m by means of the back-thinning process. This back-thinning process determines the yield of InSb IRFPAs. For finding out the deformation rule of IRFPAs in back-thinning process,this paper builds the three dimensional structure model of InSb IRFPAs with ANSYS software,focusing on the specific structure of InSb IRFPAs,and employing the method of e-quivalent modeling. In the modeling of InSb IRFPAs,the thickness of InSb photosensitive chip is reduced from 300 滋 m to 10 滋 m in a suitable step length,thus it obtains the deformation distribution of InSb IRF-PAs with different thickness of InSb photosensitive chip. Simulation results show that, when the InSb pho-tosensitive chip is thicker, the bending of InSb IRFPAs dominates, and its center region is convex up-ward. As the InSb photosensitive chip is getting thinner and thinner,the bending amplitude of InSb IRF-PAs is getting smaller and smaller. When the thickness of InSb photosensitive chip is thinned to 12 滋 m, buckling deformation on the top surface of InSb IRFPAs appears and dominates,and the buckling deform-ation will become obvious and clear as the InSb photosensitive chip is thinned further, whereafter, the buckling deformation of the whole IRFPA detector becomes slow.