Micro-BGA package reliability and optimization of reflow soldering profile

Abstract

Micro-BGA package reliability is greatly dependent on the reflow soldering process. Many defects in BGA packaging arise from an inappropriate reflow profile. Researchers have been bringing forward various optimal strategies on reflow soldering to improve this packaging reliability. However, most of them are qualitative, and hence cannot provide a satisfactory answer. Recently, a novel proposal - the heating factor, Q/sub n/ - offers us a quantitative solution to design the reflow profile. In practice, to evaluate the soldering performance of a BGA product, often six critical points on a PCB are monitored, accordingly this will give six reflow profiles, and in each of them, there is a certain value of heating factor. So how to quickly adjust the reflow oven to fulfill all these heating factors in an optimal range at the same time is a puzzle. In this work, we try to give an effective algorithm to set these reflow profiles as fast as possible.