| abstract |
A method of forming a plurality of bumps over a wafer mainly comprises providing the wafer having a plurality of bonding pads formed thereon, forming an under bump metallurgy (UBM) layer over the bonding pads wherein the UBM layer includes an adhesive layer, for example a titanium (Ti) layer or an aluminum (Al) layer, and at least one electrically conductive layer formed on the adhesive layer, removing the portions of the electrically conductive layer located outside the bonding pads, forming a plurality of bumps over the residual portions of the electrically conductive layer disposed above the bonding pads, etching the adhesive layer located outside the bumps, and then reflowing the bumps. |