Abstract
This article is the first in a two-part series analyzing solder connection failures between BGA packages and PCB assemblies. Part I examines failures attributed to oxygen intrusion during reflow, underetched solder resist, and solder paste printing problems. In the latter case, X-ray inspection revealed no abnormalities other than a variation in ball size. To get to the root cause, the corpus of the BGA was progressively ground away, leaving only the balls and an unobstructed view of the PCB surface. A description of the process, supported by detailed images, is included in the article. In Part II, scheduled for the May 2017 issue of EDFA, the author delves deeper into the analysis of voids and presents an alternate FA approach that involves grinding away much of the PCB.
