Analysis on formation of bad pixel cluster in IRFPA

Bad pixel cluster in infrared focal plane array (IRFPA) increases difficulty and complexity of bad pixel correction algorithm. Meanwhile, software-based tracking and target recognition system are generally less tolerant of bad pixels, especially large bad pixel cluster, than a human user system. This reduces the amount of qualified IRFPAs. Statistical results of bad pixels were obtained through a lot of tests on IRFPA products. Single bad pixel, bad pixel pair and bad pixel cluster accounted for 60.8%, 17.6% and 21.6% of total bad pixels respectively. Causes of bad pixel cluster were confirmed through analysis and tests, which were material defects, pattern missing, indium residual, indium bump defects, non-contact pixels, crack and potential defects exposed in reliability tests. Screening test on detector material, better fabrication technology of indium bumps, low stress technical process and structure are important to reduce bad pixel cluster, which are conducive to improve the performance of IRFPA.