US Patent 8390120 Semiconductor device and method of fabricating the same

A semiconductor device includes a via structure and a conductive structure. The via structure has a surface with a planar portion and a protrusion portion. The conductive structure is formed over at least part of the planar portion and not over at least part of the protrusion portion of the via structure. For example, the conductive structure is formed only onto the planar portion and not onto any of the protrusion portion for forming high quality connection between the conductive structure and the via structure.