Semiconductor device and methods of formation

Abstract

A layer of conductive material is formed above a bottom-most layer of interconnect structures in an interconnect layer of a semiconductor device, and the layer of conductive material is etched to define the bottom-most layer of metallization structures from the layer of conductive material. To reduce the likelihood of collapse of the free-standing metallization structures, the exposed sidewall surfaces of the free-standing metallization structures may be oxidized to form metal-oxide sidewalls for the free-standing metallization structures. The metal-oxide sidewalls may be formed using a self-aligned oxidation technique that specifically targets the sidewalls of the free-standing metallization structures for oxidation. The metal-oxide sidewalls may be formed of a metal-oxide material that increases the mechanical strength of the free-standing metallization structures, which enables the free-standing metallization structures to resist collapsing.