Adhesion between Ni/Fe lead frame and epoxy molding compounds in IC packages

Abstract

Improvement in the adhesion between an Alloy 42 (Ni/Fe alloy) lead frame and epoxy molding compounds for IC packages was studied by (i) adding modifiers to the epoxy molding compounds; (ii) using various phenol resins as curing agents; and (iii) changing the Alloy 42 die pad surface to Al, SiO, SiO2 or Si3N4. Good improvement was obtained in all three cases. When the lead frame surface was changed to Al, SiO, SiO2 or Si3N4, almost complete adhesion was observed, even after moisture-absorbed IC packages were dipped in the solder.