Analysis of the phenomenon of falling off of indium bumps from substrate during reflow process

Indium bumping is a crucial technology in FPAs (focal plane array) application. In this paper, electroplating method is tried to prepare the indium bump arrays. But one difficulty appears during the reflow process. In such process, many indium bumps fall off from the substrate. To solve such problem, its possible causes are discussed and the corresponding measures are taken. Experimental results show that the measures can effectively improve status of the falling off of indium bumps, which is consistent with the reasonable analysis. To analyze the influence of reflow process to the stress in the bump system, finite element analysis with ANSYS is adopted in this paper.