Novel die attach films having high reliability performance for lead-free solder and CSP

Properties and reliability of two kinds of die attach films were studied. A die attach film DF-335-7 developed for high temperature reflow soldering due to a lead(Pb)-free solder, was composed of a modified polyimide base resin, a thermosetting resin, and a silver filler. Relationships among peel strength, work of adhesion, water absorption, package crack resistance, and composition of the film were discussed. Another die attach film DF-400 for new advanced packages such as a Fine-pitch Ball Grid Array (F-BGA) and a Chip Scale Package (CSP) was studied. Relationships among chip warpage, attaching temperature, glass transition temperature (Tg) of a base resin, and package crack resistance were discussed.