A study on reliability modeling for through hole cracking failure in thermal enhanced PBGA laminate

Recently, BGA-type packages are widely used in the microelectronics industry. Particularly Plastic BGA (PBGA), of various body sizes, are in use throughout the world. From a PBGA reliability stand point, several improvements have taken place in both laminate design and manufacturing processes. However, reliability concerns still remain, primarily to the organic laminate fabrication process. The purpose of this paper is to generate a failure model of through hole cracking which is one of the unique challenges on organic laminates. During thermal cycle stress testing, copper plated through holes are subjected to internal stress due to the CTE mismatch of laminated materials. Consequently open failure is induced due to the through hole cracking. In this evaluation, cavity down-type PBGA with heatspreader was evaluated with several thermal cycle conditions and it is demonstrated that fatigue failure of through holes can be simulated with a modified Coffin-Manson equation.