InSb面阵探测器铟柱缺陷成因与特征研究

Causes and characteristics of indium bump defects in InSb focal plane array

通过基于正性光刻胶的不同像元尺寸铟柱阵列及器件制备,研究In Sb面阵探测器铟柱缺陷成因与特征.分别研制了像元尺寸为50μm×50μm、30μm×30μm、15μm×15μm的面阵探测器的铟柱阵列,并制备出In Sb面阵探测器,利用高倍光学显微镜和焦平面测试系统对制备的芯片表面形貌、器件连通性及性能进行了检测与分析.研究结果表明:当像元尺寸为50μm×50μm时,芯片表面形貌和器件连通性测试结果较好;随着像元尺寸减小,芯片表面会出现铟柱相连或铟柱缺失缺陷,器件连通性测试结果与表面形貌相吻合.铟柱相连缺陷是由光刻剥离时残留铟渣引起的铟相连造成;铟柱缺失缺陷是由光刻时残留光刻胶底膜引起的铟柱缺失造成.器件相连缺陷元的响应电压与正常元基本相同,缺失缺陷元的响应电压基本为0,其周围最相邻探测单元响应电压相比正常元增加了约25%.器件缺陷元的研究结果,对通过优化探测器制作水平提升其性能具有重要参考意义.

In order to study the causes and characteristics of indium bump defects in infrared focal plane arrays（ IRFPA）,during the fabrication of InSb IRFPAs,indium bumps of different pixel sizes were studied using positive photoresist. Then,the surface morphology of the chip,the connectivity of the detector,and the performance of the detector were characterized using an optical microscope and an FPA test stand,respectively. The results show that the chip surface and detector connectivity of the 50μm × 50 μm pixel size sample is better than other chips. Due to the small pixel size,the surface topography of the chip is connected or missing to the defective indium bump. The connectivity test results are consistent with the test results of the indium raised surface topography. The connected defects are due to the surface of the indium bumps caused by indium remnants during lithography and stripping.The missing defects are due to the lack of elemental indium bumps caused by positive photoresist residual during photolithography. The response voltage of the connected faulty component is basically the same as the response voltage of the normal component. The response voltage of the defect defective element is zero,and the response voltage of the nearest neighbor element is increased by about 25%compared with the normal element. The result has important reference significance for improving the performance of the FPA detectors by optimizing the production process.