Warpage Measurement System with Systematic Error analysis

摘要

Out-of-plane displacement (warpage) of the electronic package is an essential source of the electronic device failure. It is caused from the mismatch of the coefficient of thermal expansion among different parts of IC device. Here a projection Moire system is presented for monitoring and analyzing warpage during packaging. Projection moire is particularly useful to measure warpage of surfaces with components. While this method shows promising features, it will give erroneous results if improperly used. In this paper, the formula of the systematic error is deduced. Based on the analysis, compensation could be done to eliminate the systematic error and guarantee an accurate measurement results.