SEMICONDUCTOR DEVICE HAVING BUCKET-SHAPED UNDER-BUMP METALLIZATON AND METHOD OF FORMING SAME

摘要

A semiconductor device includes a first under-bump metallization (UBM) layer disposed over a bond pad, a dielectric layer above an interconnect layer having a via exposing at least a portion of the first UBM layer. A second UBM layer is disposed above the first UBM layer and forms a UBM bucket over the via. The first UBM layer and UBM bucket are 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.

主权项

1. A method of forming a semiconductor device including a substrate having an active layer and interconnect formed on the active layer, and the interconnect having a bond pad, the method comprising:
forming a first under-bump (UBM) layer over the bond pad and directly contacting the bond pad; forming a dielectric layer above the interconnect having a via exposing at least a portion of the first UBM layer, wherein a part of the dielectric layer is above a side of the UBM portion; forming a second UBM layer over the via and the first UBM layer to form a UBM bucket; and forming a dielectric cap layer over the dielectric layer and a portion of the second UBM layer; wherein the UBM bucket is formed so that at least a portion of the UBM bucket is in the dielectric layer, and the UBM bucket defines a region located in the dielectric layer for accommodating a portion of a solder ball; and wherein the first UBM layer extends past a periphery of the solder ball when the solder ball is accommodated in the region defined by the UBM bucket.