Patent ID: 8530344

Claim:
A method for manufacturing fine-pitch bumps at least comprising: providing a silicon substrate having a surface, a plurality of bond pads disposed at the surface and a protective layer disposed at the surface, wherein the protective layer comprises a plurality of openings, and the bond pads are revealed by the openings; forming a titanium-containing metal layer on the protective layer and the bond pads, the titanium-containing metal layer comprises a plurality of first zones and a plurality of second zones located outside the first zones; forming a photoresist layer on the titanium-containing metal layer; patterning the photoresist layer to form a plurality of opening slots corresponded to the first zones of the titanium-containing metal layer; forming a plurality of copper bumps at the first zones of the titanium-containing metal layer, each of the copper bumps comprises a first top surface and a first ring surface; heating the photoresist layer to ream the opening slots of the photoresist layer, and the heat process enables the photoresist layer to form a plurality of body portions and a plurality of removable portions; etching the photoresist layer to remove the removable portions and reveal the titanium-containing metal layer, each of the body portions comprises an inner lateral surface; forming a plurality of bump protection layers on the titanium-containing metal layer, the first top surface and the first ring surface of each of the copper bumps, wherein each of the bump protection layers comprises a metallic coverage portion and a bump coverage portion, the bump coverage portion comprises a second top surface and a second ring surface, the first top surface and the first ring surface of each of the copper bumps are covered with each of the bump coverage portions, and the second ring surface and the inner lateral surface of each of the body portions are spaced apart from each other to define a gap; plating a plurality of gold layers at each of the gaps, the second top surface and the second ring surface of each of the bump coverage portions, and each of the gold layers comprises a third top surface; removing the body portions of the photoresist layer; and removing the second zones of the titanium-containing metal layer to enable each of the first zones of the titanium-containing metal layer to form an under bump metallurgy layer located under each of the copper bumps, each of the under bump metallurgy layers comprises a bearing portion located under each of the copper bumps and an extending portion protruded to the first ring surface of each of the copper bumps, and the extending portion of each of the under bump metallurgy layers is covered with the metallic coverage portion of each of the bump protection layers.