What is resin bleed out?
Resin bleed out is the migration of organic components of the adhesive onto the surrounding surface due to surface energy differences between the resin and substrate. Bleed is both substrate and adhesive dependent. Substrate surface conditions, such as roughness, cleanliness, presence and level of substrate antioxidants, presence of anti-bleed agents or primers/coupling agents may affect bleed out. Process conditions, such as dwell time before cure and cure profile, can affect the amount of bleed a particular adhesive exhibits. Possible effects include bleed out onto bond surfaces causing poor wire bondability and/or poor adhesion of molding compounds. Bleed out can be reduced by reduction of dwell time, cure optimization, substrate modification, plasma cleaning (in some cases, see above Effects of Plasma Cleaning) and liquid etching.