Improved Adhesion between Kapton Film and Copper Metal by Silane-Coupling Reactions

Abstract

Kapton film, poly[(N,N′-oxydiphenylene)pyromellitimide], was modified by silane-coupling reactions using 3′(trimethoxysilyl)propoxy-2-hydroxypro-pyl-1,3-diazole (Si-imidazole) to improve the adhesion with copper metal. The Kapton film surface was first treated with argon plasma for 30 s, then dipped into a methanol solution of Si-imidazole (0.01 wt %), followed by heating at 110°C for 90 min. The Kapton surfaces, modified by the argon plasma and Si-imizadole coupling reactions, were analyzed by water contact-angle measurement, atomic force microscopy, and XPS. The Si-imidazole modification showed a large increase in adhesion between the copper metal and the Kapton film. The peel strength of the copper metal/Kapton film joint increased from 0.94 to 2.4 N/5 mm. The failure occurred at the interface between the Si-imidazole and the Kapton film layer. We conclude that the Si-imidazole modification is an effective treatment for improvement of the adhesion between copper metal and Kapton film. © 1999 John Wiley & Sons, Inc.