Adhesion comparison between thermosetting and thermoplastic resin systems based on poly(bisphenol A-co-epichlorohydrin) chemistry

The application of the underfill materials has been to enhance the solder joint fatigue life in flip chip assembly, where normally only thermosetting systems have been extensively employed in industry. However, thermoplastics may be of great economic/cost interest as underfill for some low end use microelectronic products; and furthermore, such investigations could enrich our understanding of the potential thermoplastic systems. In this paper both thermosetting and thermoplastic epoxy resins were studied for the feasibility as underfill materials. The former includes basic liquid resin and advanced solid resin of different molecular weight, while the latter is the so-called phenoxy resin. The solution and hot melt approach were taken for the assembly procedure of the die shear strength test at selected solid content and curing/drying condition. The die shear strength of the systems was collected, which could enable us to get insights into the effects of aging, temperature and coupling agent, etc., for the thermosetting and thermoplastic materials.