Study on Defective Elements from Indium Bump Preparation in Focal Plane Array Fabrication

摘要

The defective elements from indium bump preparation in FPA fabrication are tested by optical microscopy and FPA testing bench. Results show that the defective elements from indium bump fabrication include connecting defective elements and missing defective elements. It is easy to identify missing defective elements by FPA testing bench because the response voltage of defective elements is zero and response voltage of other elements around defective element is higher than that of normal elements. And it is difficult to identify connecting defective elements by FPA testing bench because the response voltage of connecting defective elements is basically the same as that of normal elements. The defective elements from indium bump fabrication are due to the indium bump with connecting or missing caused by the process of photolithography, eroding and lift-off. Fabrication process such as photolithography, eroding and lift-off is optimized to reduce defective elements from indium bump fabrication.