Adhesion of copper on polyimide deposited by arc-enhanced deposition

Polyimide films of Kapton EN were coated with copper by arc-enhanced deposition. This deposition method offers the possibility to influence the degree of ionization by setting the anodic arc current without varying other deposition parameters. Estimation of the electron density depending on the anodic arc current is given by flat probe measurements. Adhesion measurements by pull test and peel test were carried out to examine the influence of vapor ionization on adhesion. The adhesion measurements do not show a uniform dependence on the anodic arc current and bias voltage, and the adhesion strength never reached values obtained by thermally evaporated copper coatings. Apparently, either ion impact or vacuum ultraviolet radiation of the anodic arc damages the polymer by a significant amount.