EVALUATING THE MECHANICAL RELIABILITY OF REBALLED BGA MODULES
Author: Daryl L. Santos Company: Binghamton University Date Published: 2/2/1999
Pan Pacific Symposium
Abstract: The need for Ball Grid Array (BGA) rework may arise from a variety of reasons: placement or other assembly-related errors, design errors, or rescuing of a perfectly functioning BGA module from an otherwise defective board. Because BGA devices typically represent high value components compared to other components on the assembly, the rework need is significant. Previous, significant literature discusses the salvaging of a printed circuit board for BGA replacement – wherein a BGA module is typically discarded and, after site preparation, the board receives a new BGA component. The focus of this paper is on the reballing process step of BGA rework or, in other words, the salvaging of the BGA module. Specifically, this paper serves to evaluate the mechanical reliability of reballed BGA modules. The modules chosen for rework and analysis in this paper are Ceramic BGAs (CBGAs). The CBGAs used in this effort are full array, 255-I/O CBGAs (16x16 with one corner ball position intentionally vacant – for orientation designation) with 1.27 mm center-to-center distances. The reliability is measured by ball shear-force testing. Here, the components are tested prior to assembly.