A simple way to predict the flip–chip gap

Abstract

Using laser scanning confocal microscopy measurement, a concise method for extracting the indium bump shape in microelectronics was first established. The extracted bump shape was then used as the input for finite element analysis. The modeled one-bump deformation was used to predict the final flip–chip gap after bonding. Dovetailed with the results of cross-sectional scanning electron microscopy, this simple and non-destructive method for predicting a flip–chip gap of the order of 10 microns or less was eventually validated.