PCB Designers Notebook: Reducing Occurrence of Voids in Solder Balls

摘要

An ongoing problem is excessive voiding within the spherical contact of BGA-packaged ICs. Assembly specialists question the origin of these voids, often random as well as varying in size and number. Of primary concern is the effect of voids on product reliability. The industry's concern regarding voids will continually be debated, but for now, we can refer to the newly released IPC-7095A standard. This document attempts to define criteria for void acceptance. It makes no sense to throw away good product or rework where a void is identified without some indication as to the complexity and the impact on reliability of that condition.