No-bleed die attach adhesives

Abstract

Resin bleed out (RBO) is a major problem encountered when using die attach adhesives on metal or organic substrates or on top of another die. RBO to the edge of the substrate and/or onto the wire-bonding pad on a die, contaminates these surfaces. This hinders the formation of good wire-bonds between the die-top and the substrate or the wire-bonding fingers. The issue of resin bleed was tackled in three steps: First - understanding the nature of the surface (e.g. surface energy, roughness), and resin properties (e.g. viscosity, molecular weight, surface tension, polarity). Second - modelling the effect of the surface and liquid properties (input), on the adhesive performance (output). Third - design and develop new resins, based on the analysis, to reduce and eliminate resin bleed.