We have studied the adhesion of a sputtered copper film (thickness 5000 Angstroms) to flexible polyimide substrates between 1 mil and 5 mil thick. The polyimide types include Kapton (based on the monomers of pyromellitic dianhydride and oxydialine, i.e., PMDA-ODA) and Upilex (based on the bi-phenyl tetracarboxylic dianhydride monomer). (A. S. Wood, 1988) For each of these polyimides, a clear difference in adhesion is observed when the polymer surface has been treated with a simple AC nitrogen glow discharge. We used a tape test to estimate the strength of the adhesion bond. The difference in adhesion only becomes apparent after the film and substrate have been subjected to either boiling water or steam for 30 minutes or more; the difference becomes quite clear after two hours. After two hours, about 100% of the copper film fails the adhesion tape test for an untreated polyimide surface; for a plasma modified surface, less than 1% of the copper film fails the tape test. In this thesis, we present experimental data on the effects of moisture, cleaning procedures, and plasma surface modification in copper - polyimide adhesion. A crude model of the AC discharge plasma is discussed.
Library of Congress Subject Headings
Thin films--Testing--Analysis; Metal films--Testing--Analysis; Cathode sputtering (Plating process); Polymides
Department, Program, or Center
School of Chemistry and Materials Science (COS)
Ma, Jong-Bong, "Adhesion of sputtered copper to plasma-treated polyimide substrates" (1991). Thesis. Rochester Institute of Technology. Accessed from
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