Warpage measurement of various substrates based on white light shadow moiré technology

Abstract

In this paper, warpage of various substrates are measured with a noncontact shadow moiré technology. Meanwhile, phase-shifting technology is applied to the analysis of fringe pattern images of substrates obtained by shadow moiré. Sensitivity of the fringe pattern analysis is demonstrated to be significantly increased. Two types of samples, QFN (Quad Flat No-lead Package) metal substrates, BGA (Ball Grid Array) substrates are measured by the system. This paper will show that the presented system is a powerful tool for measuring the warpage of various substrates.