Siliconware Precision Industries Co., Ltd.

Chun-chi Ke

Feng-Lung Chien

Randy Hy Lo

A method is proposed for forming circuit probing (CP) contact points on fine pitch peripheral bond pads (PBP) on a flip chip for the purpose of facilitating peripheral circuit probing of the internal circuitry of the flip chip. The proposed method is characterized in the forming of a dual-layer NiV/Cu metallization structure, rather than a triple-layer Al/NiV/Cu metallization structure, over each aluminum-based PBP, which includes a bottom layer of nickel-vanadium (NiV) deposited over the aluminum-based PBP and an upper layer of copper (Cu) deposited over the nickel-vanadium layer. When low-resolution photolithographic and etching equipment is used for photoresist mask definition for selective removal of the NiV/Cu metallization structure, the resulted photoresist masking can be misaligned to the PBP. However, since no aluminum layer is included in the metallization structure, a Cu/NiV specific etchant would only etch away the copper layer and the nickel-vanadium layer but not the aluminum-based PBP, thus leaving the unmasked portion of the aluminum-based PBP intact.

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Taichung Hsien, Taiwan

Chun-chi Ke