Semiconductor device having bucket-shaped under-bump metallization and method of forming same

Abstract

An embodiment of a method of forming a semiconductor device that includes a substrate having an active layer and interconnect formed on the active layer is described. The method includes: forming a dielectric layer above the interconnect having a tapered via exposing at least a portion of a first metal layer; forming an under-bump metallization (UBM) layer over the tapered via and the first metal layer to form a UBM bucket; and forming a dielectric cap layer over the dielectric layer and a portion of the UBM layer. The UBM bucket is configured to support a solder ball and can advantageously block all alpha particles emitted by the solder ball having a relevant angle of incidence from reaching the active semiconductor regions of the IC. Thus, soft errors, such as single event upsets in memory cells, are reduced or eliminated.

Dependencies are inferred from the claim text.