Reliability study of the laminate-based flip-chip chip scale package

The just about chip size package (JACS-Pak) design was developed for portable product applications. The package elements are solder bumped die, an epoxy underfill resin with inorganic filler, a low cost double-sided, semi-rigid epoxy glass or flex substrate, and solder ball terminals. This paper focuses on the board level reliability of the JACS-Pak package and benchmarks it with respect to standard ball grid array (BGA) packages, such as the glob top-BGA (GT-BGA) and the over molded pad array carrier (OMPAC). The samples (packages solder reflow attached to PCBs) are subjected to the liquid-to-liquid thermal shock testing from -55 to 125/spl deg/C at a rate of 5.8 cycles per hour. The results are compared to the thermal fatigue performance of standard 196 I/O GT-BGA and the 1.5 mm pitch OMPAC package. In addition, temperature cycling, temperature-humidity bias (THB), high temperature storage life (HTSL), and autoclave reliability tests were performed on the JACS-Pak package with excellent results.