Solder joints between a ceramic ball grid array (CBGA) and a printed circuit board (PCB) generally suffer important thermal strains and stresses during the operation of devices as well as under temperature variations. Mainly, these tend to increase the thermal stress concentration in solder joints. In this study, moire interferometry is used to measure the power-induced thermal displacement in the CBGA assembly. The experimental study is performed under various environmental temperatures using different power levels. Two types of thermal strain distributions are found in the assembly, depending on the thermal loadings. The stress concentrations are located in the CBGA assembly. Then, based on the relative displacement between the CBGA and the PCB, the shear stress on the solder ball is determined. Moreover, the effects of different thermal loadings on the CBGA as well as their impact on the reliability of CBGA solder balls are discussed in details.

Date Published: 29 May 2002
PDF: 4 pages
Proc. SPIE 4537, Third International Conference on Experimental Mechanics, (29 May 2002); doi: 10.1117/12.468758

Published in SPIE Proceedings Vol. 4537:
Third International Conference on Experimental Mechanics
Xiaoping Wu; Yuwen Qin; Jing Fang; Jingtang Ke, Editor(s)