BOTTOM-UP FILL (BUF) OF METAL FEATURES FOR SEMICONDUCTOR STRUCTURES

摘要

Bottom-up fill approaches for forming metal features of semiconductor structures, and the resulting structures, are described. In an example, a semiconductor structure includes a trench disposed in an inter-layer dielectric (ILD) layer. The trench has sidewalls, a bottom and a top. A U-shaped metal seed layer is disposed at the bottom of the trench and along the sidewalls of the trench but substantially below the top of the trench. A metal fill layer is disposed on the U-shaped metal seed layer and fills the trench to the top of the trench. The metal fill layer is in direct contact with dielectric material of the ILD layer along portions of the sidewalls of the trench above the U-shaped metal seed layer.