Study of metal-polymer adhesion—A new technology: Cu plasma PIB
Adhesion between copper and n-type parylene (PA-N) has been studied. The PA-N film was deposited on Si(100) substrate by vapor deposition polymerization (VDP), and the Cu film was deposited on PA-N by plasma partially ionized beam (Plasma PIB) as well as other deposition techniques as a comparison. The adhesion strength was measured by 90° peel test after the sample was cleaved into a strip to define geometry. A peel strength of greater than 70 g/mm between the Cu film and PA-N was achieved by Cu Plasma PIB. X-ray photoelectron spectroscopy (XPS) studies found no Cu-O-C bond formation at Cu-parylene surface, while secondary ion mass spectrometry (SIMS) studies showed that a significant amount of Cu was shallowly implanted into the PA-N, with an average concentration of 1017–1018 atoms/cm3 near the interface. The results showed that a physically intermixing layer of about 100Å between the two phases formed by shallow implantation of Cu into PA-N was the main mechanism of adhesion. A suggested model is proposed correspondingly.