Health monitoring for electronic package using a simple Moire interferometry

Abstract

Like a diagnosis of human body, it is important to monitor conditions of electronic packages in use. Even if electronic packages are sound in the beginning, thermal cycles during operations can produce fatigue cracks that lead to the system failure eventually. If we know the crack length in the package in real-time, a fatal damage can be prevented before the system failure. Currently, there are no simple methods for real-time monitoring of electronic packages in use. In this research, we propose a non-destructive monitoring method that detects the crack length in electronic packages. The electronic package in use is heated continuously by itself. When the crack at a weak site of the electronic package occurs, thermal deformation on the chip side is changed. Therefore, we can measure these micro deformations by using Moiré interferometry and find out the crack length. The proposed monitoring method is applied to ACF type package specimens. Experimental results show that the crack length of the electronic package affects the thermal deformation of the chip. If we have data of thermal strain by a specific crack length, we can monitor the crack length in real-time. Since the failure of a super-computer or network-server system affect the tremendous damage, we must know the health conditions of electronic packages in real-time. This research focuses the health monitoring of the electronic package of these system.