ADVANCED SHADOW MOIRE WITH NON-CONVENTIONAL IMAGING ANGLES

Abstract

With the increasingly smaller electronic package size, warpage of electronic packages becomes an important measurement related to the reliability of the products. Higher sensitivity out-of-plane deformation techniques are required to capture the smaller deformations of tiny packages for enhanced design analysis and model verification. The higher sensitivity is realized using non-zero viewing angles with the conventional shadow moiré technique. Advanced configurations to accommodate the non-zero viewing angles are developed to cope with direct reflection encountered on the conventional setup. An expanded governing equation for the configuration is derived and verified experimentally. Then the proposed configuration was implemented in the testing of an actual package to demonstrate the advantages that accrue from the higher sensitivity.