摘要 |
A method for forming a bump on under bump metallurgy according to the present invention is provided. A bonding pad is first formed on the active surface of a wafer. Subsequently, a passivation layer is formed on the active surface of the wafer and exposes the bonding pad. An under bump metallurgy is formed on the bonding pad. A layer of film is formed on the passivation layer and overlays the under bump metallurgy. Afterward, the portion of the film on the under bump metallurgy is exposed to a UV light and the exposed portion of the film is removed to expose the under bump metallurgy. A solder paste is applied to the under bump metallurgy and the remaining film on the wafer is removed. Finally, the solder paste is reflowed to form a spherical bump.
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