| 摘要 |
A method for forming a solder bump pad (22), and more particularly converting a wire bond pad (12) of a surface-mount IC device (10) to a flip chip solder bump pad (22), such that the IC device (10) can be flip-chip mounted to a substrate. The process generally entails an aluminum wire bond pad (12) on a substrate, with at least a portion of the wire bond pad (12) being exposed through a dielectric layer (16) on the substrate. A nickel layer (24) is then deposited on the portion of the wire bond pad (12) exposed through the dielectric layer (16). The nickel layer (24) is selectively deposited on the exposed portion of the wire bond pad (12) without use of a masking operation, such as by an electroless deposition technique. The nickel layer (24) completely overlies the aluminum wire bond pad (12), and therefore protects the bond pad (12) from oxidation due to exposure. Thereafter, the solder bump pad (22) is formed by depositing a solderable material on the nickel layer (24). The solder bump pad (22) is formed to cover only a limited portion of the nickel layer (24), and its shape is tailored to achieve the required geometric characteristics for a solder bump (26) subsequently formed on the solder bump pad (22).
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