A Reliability Qualification Process for BGA Rework Limit

In recent years BGA packaging types have arisen to be one of the most popular packages in the IC market. BGA packaged ICs benefit various industries such as control systems, artificial intelligence products, and automatic test equipment. However, reworking BGA components is a complicated process that also impacts PCA reliability. Many variables that include precise temperature control and solder paste types are involved in BGA rework process. The PCA reliability after BGA reworks cannot be predicted before an actual rework is done. Therefore, most companies err on the side of caution to limit the BGA reworks. In this paper, we present a reliability qualification process that backward qualifies PCAs with finished aggressive reworks, especially for intensive BGA reworks on single PCA. One case study on high-density PCA is introduced as an example. The successful inspection results from cross-section and dye-and-pry demonstrate the PCA reliability after multiple BGA reworks. The qualified rework cycles provide references and guideline for future BGA reworks on the same category products.