Focus ring for a plasma-based semiconductor processing tool

Abstract

A focus ring for a plasma-based semiconductor processing tool is designed to provide and/or ensure etch rate uniformity across a wafer during a plasma etch process. The focus ring may include an angled inner wall that is angled away from a center of the focus ring to direct a plasma toward the wafer. The angle of the angled inner wall may be greater than approximately 130 degrees relative to the top surface of the wafer and/or may be less than approximately 50 degrees relative to an adjacent lower surface of the focus ring to reduce and/or eliminate areas of overlapping plasma on the wafer (which would otherwise cause non-uniform etch rates). Moreover, an inner diameter may be configured to be in a range of approximately 209 millimeters to 214 millimeters to further reduce and/or eliminate areas of overlapping plasma on the wafer. In this way, the focus ring provides and/or increases etch rate uniformity across the wafer, which may reduce structural variations across semiconductor devices being formed on the wafer and/or may increase processing yield.