| 摘要 |
PURPOSE: A method for fabricating an unleaded solder bump is provided to reduce fabricating cost and easily control a plating process by forming copper on UBM(under bump metallization) and by diffusing copper in a reflow process of solder. CONSTITUTION: A wafer is prepared which has a passivation layer with an open electrode pad. An UBM is formed on the wafer. A photolithography process of photoresist is performed on the UBM except a portion corresponding to the electrode pad. A copper layer(22) is formed on the UBM corresponding to the electrode pad. The copper layer is plated with solder. The photoresist is eliminated. The UBM is etched by using the solder as a mask while the solder is reflowed to fabricate a solder bump(34). |
