Warpage resolution for Ball Grid Array (BGA) package in a fully integrated assembly

The necessity for a more dense silicon to double its device application and a reliable green packaging solution that can withstand higher reflow requirement is to today´s semiconductor industry trend and need. Materials and packaging designs were continuously developed to reduce the integrated circuit (IC) package internal stress during package and board mount assemblies. In response with the said requirement and Cypress objective for a full-in line assembly facility, each process steps and materials used were carefully studied in order to satisfy both conditions. Thus, the objective of the study is to assess the effects of different bill-of material (BOM) combinations for a Ball Grid Array (BGA) package that will give the least if not eliminate strip and package warpage in a fully integrated assembly in both ambient and elevated temperatures. Focusing on the materials used, the overall combination must be reliable and provide the best response in terms of faster package assembly processing time. Interactions between different halogen-free substrates, mold compounds, and die attach adhesives with varied coefficient of thermal expansions (CTE´s) were considered coupled with different silicon densities. Results showed that a low CTE substrate material will provide the best alternative packaging solution in resolving the warpage issues.