A surface energy approach for analyzing die attach adhesive resin bleed

Abstract Die attach adhesive resin bleed is a phenomenon that occurs when the resinous vehicle separates from the polymeric adhesive and migrates over the surface of the substrate beyond its intended boundary. A problem will occur if the material spreads over an area where wirebonding is to be performed. In this paper, a relatively new surface energy approach involving contact angle measurements (three-liquid probe method) was used to determine the mechanism of resin bleed. In addition, a surface profilometer was used to measure the roughness of the epoxy (fiber filled) substrate, and the effect of roughness of the substrate on resin bleed is also discussed. Preliminary results suggest that acid-base interactions play a significant role in resin bleed while no correlation was seen with roughness. The three-liquid probe method appears to hold promise for analysis of resin bleed behavior. Keywords: Acid-base approachresin bleedcontact angleswetting and spreading.