Abstract: A novel UBM structure for improving the strength and performance of individual UBM layers in a UBM structure is disclosed. In one aspect, a UBM structure for disposal onto an electrically conductive element comprised of aluminum is disclosed. In one embodiment, the UBM structure comprises a tantalum layer disposed over the aluminum electrically conductive element, and a copper layer disposed over the tantalum layer, where the UBM structure is configured to receive a solder ball thereon.

Abstract: An edge bead removal process is disclosed. The process includes providing a wafer having a feature layer, coating a photoresist on the feature layer, rotating the wafer, and removing an edge bead from the wafer by removing an edge bump portion from the edge bead and removing an edge region from the edge bead.

Abstract: A novel under-bump metallization (UBM) structure for providing electrical communication is described. The UBM structure includes a plurality of metallic layers, which are deposited onto a bonding pad of a semiconductor device, such as a semiconductor chip. The UBM structure may be provided as an interface between the bonding pad and a solder bump deposited over the UBM structure. In one example, the UBM structure includes layers of nickel and copper in which nickel is the upper layer in contact with the solder bump and copper is the lower layer in contact with the bonding pad. The nickel layer is formed to include a downwardly depending perimeter portion, which serves as a cover to the copper layer of the UBM structure. Accordingly, the copper layer is shielded from contact with the solder material during the reflow process, thereby avoiding undesirable reactions between the copper and solder.