On-Line Measurement of Thermally Induced Warpage of BGAs with High Sensitivity Shadow Moiré On-Line Measurement of Thermally Induced Warpage of BGAs with High Sensitivity Shadow Moiré

The thermally induced warpage of electronic substrates is a significant concern in manufacturing processes. The ability to evaluate substrate behavior with respect to temperature is particularly important to manufacturing engineers. Previous measurement of thermally induced warpage on Printed Circuit Boards (PCBs) using general Shadow Moiré cannot provide enough sensitivity for modern electronic substrates and packages. Today’s chip-carrier substrates and packages have tighter flatness requirements than the older through-hole connection designs. A successful application of the phase-stepping technique to general Shadow Moiré is reported in this paper. This application has made fringe pattern analysis fully automated and significantly increased the effective sensitivity of the analysis.