Plasma Surface Modification of Aromatic Polyester (Vecstar OC®) Films for Copper Metallization - Dynamic Surface Properties of Plasma-Modified Vecstar OC Films

Vecstar OC films were modified by Ar, O-2, N-2 and NH3 plasmas and further heat-treated in order to improve their adhesion to deposited copper metal. Effects of these plasma modifications and heat treatment were evaluated from water contact angle measurements, surface roughness measurements with a scanning probe microscope and chemical composition measured with XPS. The plasma modification alone is not efficient, but the combination of plasma modification and heat treatment is effective in improvement of adhesion between copper metal and the Vecstar OC films. Furthermore, O=C groups and amino groups formed by the plasma modification contribute to adhesion improvement. In order to achieve an effective improvement, the O=C and amino groups should be present in the topmost layer (within 3 nm depth from the film surface) of the Vecstar OC films. The O=C and amino groups not available in the topmost layer do not contribute to adhesion improvement. The heat treatment on a glass plate helps migration of the O=C and amino groups from the inner layer to the topmost layer of the plasma-modified Vecstar OC films.