Evaluation of thermal deformation behavior in electronic package using UV moire interferometry

In recent years, moire interferometry method has been used extensively in the electronics industry to determine thermal strains caused by temperature changes in microelectronics devices. The size of a flip-chip package has getting smaller. To measure thermal deformations of these small flip-chips, instruments with much higher resolution are required. Many researchers have tried to achieve this resolution enhancement of moire interferometry by using a phase-shifting method. But the phase-shifting method has physical limitations. Fundamentally to get higher resolution, the laser source should be changed. In this article, we constructed a moire interferometry system by utilizing an ultraviolet laser (λ=325nm). This UV system realizes higher resolution than He-Ne (λ=633nm) system. And we apply this system to evaluate thermal deformation in flip-chip package.