XPS analysis of Cu-glass interface obtained by RF ion-plating

The XPS (X-ray photoemission spectroscopy) analysis of the Cu-SiO/sub 2/ interface was undertaken to obtain a better understanding of the cause of the enhanced adhesion reported in ion-plated films. The results indicate the formation of a (Cu/sub 2/O)/sub x/Si interfacial layer, nearly 50 AA thick, lying mostly on the Cu side of the interface. Theories of metal-glass adhesion suggest that this (Cu/sub 2/O)/sub x/Si layer leads to chemical bonding between Cu and SiO/sub 2/ and is responsible for the enhanced adhesion of the ion-plated films. Because of the reported low reactivity of Cu with SiO/sub 2/ it is believed that the use of negative substrate bias along with the (Cu+Ar) plasma in RF ion plating aids in the chemical reaction between Cu and SiO/sub 2/.<>