Characterization of a novel fine-pitch ball grid array package for flash memory application

Abstract

This paper describes the reliability characterization of a novel 63 ball Fine-pitch Ball Grid Array (FBGA) package for Flash memory application. The package has a fully populated core of 48 functional balls (6/spl times/8 array), with an additional outer 15 support balls located in groups of 4 (one group partially depopulated) at each corner. The reliability characterization of the 63 ball FBGA package was conducted at both component and board level. The package level characterization used a suite of reliability tests. The board level reliability under temperature cycling was performed using two different accelerated temperature cycling conditions (0/spl deg/C to 100/spl deg/C, and -40/spl deg/C to 125/spl deg/C). The data were analyzed using a lognormal distribution. An acceleration factor between the two accelerated thermal cycling tests was calculated and compared to the Coffin-Manson model. Mechanical characterization of the board level assembly was also conducted, using three-point bending and drop impact tests, to estimate solder attach integrity.