Understanding and Controlling Resin Bleed Out

Die attach pastes, which consist of resin, curing agent, catalyst, filler and additives, have been extensively used to attach die onto lead frames in various electronic packages. One of the issues commonly encountered during package assembly is Resin bleed-out (RBO), or epoxy bleed out (EBO). Resin Bleed Out is a surface phenomenon whereby fractions of the organic resin or reactive diluents migrate along the surface of the substrate or up the side of the semiconductor chip due to surface energy difference between the resin & the substrate. The movement of the low viscosity polymer molecules is by capillary action