Method of adhesion to a polyimide surface by formation of covalent bonds

A polyimide surface (18) of a semiconductor device (12) is pretreat the polyimide layer with a hydroxyl amine solution at an elevated temperature to form functional groups that react with an underfill encapsulant (16) to form covalent bonds during a cure cycle between the polyimide layer and the encapsulant material between the semiconductor device and a substrate (10). The hydroxyl amine solution include a reagent such as 2,(2-aminoethoxy) ethanol dissolved in a solvent like N-methyl pyrolidione at 65 DEG C. for sixty seconds. The hydroxyl amine solution may be sprayed onto the polyimide layer, or deposited by vapor deposition. The semiconductor die with the treated polyimide layer is attached to the substrate by DCA methods leaving a gap between the assemblies. The encapsulant is introduced between the semiconductor die and the substrate and cured to form a covalent bond with the polyimide layer and an environmental seal between the assemblies resulting in enhanced adhesion.