Plasma graft polymerization of vinylimidazole onto Kapton film surface for improvement of adhesion between Kapton film and copper

Kapton film was modified by means of the plasma graft polymerization of vinylimidazole for the improvement of the adhesion with copper metal. Argon plasma exposure generated hydroperoxides at the surface of the Kapton film. Hydroperoxides generated by the argon plasma exposure could initiate the graft polymerization of vinylimidazole. The graft polymerization was restricted at the surface of the Kapton film and never occurred on the inside of the Kapton film. The graft polymer layer was 150–200 nm thick. The surface modification by the plasma graft polymerization of vinylimidazole led to the improvement of adhesion between Kapton film and copper metal. A part of the copper metal made a complex with imino groups in the vinylimidazole chains graft‐polymerized onto Kapton film. The complex is considered to contribute to the improvement of the adhesion.