| abstract |
A method is disclosed for improving the bonding strength of wire bonds on semiconductor chips. Aluminum-silicon-copper is employed as the metal for wire bonding-pads. Openings are formed in the passivation layer over the bonding-pads. The exposed metal in the openings is treated with a fluorine containing F-plasma. A thin passivation film, with C, F, and O content is formed over the metal bonding pads. This protective film prevents the formation of pitting and staining of the bonding-pads when the wafer is subjected to repeated developing solutions during the color filter process performed for the CMOS image sensors, for example. Consequently, the wire bonds formed during the packaging of the chips are stronger and more reliable. |