Methods and systems for managing byproduct material accumulation during plasma-based semiconductor wafer fabrication process

A method for managing byproduct accumulation during a plasma-based semiconductor wafer fabrication process, comprising:

• positioning a wafer on a wafer support structure such that a peripheral portion of the wafer extends radially outward from an outer perimeter of a top surface of the wafer support structure to an outer perimeter of the wafer, and such that a lower peripheral open region is formed between the peripheral portion of the wafer and an edge ring structure that extends below the peripheral portion of the wafer without physically contacting the wafer, wherein the lower peripheral open region is exposed to a plasma generation region located above a top surface of the wafer;
• etching of a material on the top surface of the wafer by generating a plasma within the plasma generation region, the etching causing accumulation of byproduct material within the lower peripheral open region between a bottom surface of the peripheral portion of the wafer and the edge ring structure;
• supplying a flow of a byproduct volatizing gas through the lower peripheral open region while performing the etching, wherein the byproduct volatizing gas is formulated to undergo dissociation when exposed to reactive species of the plasma to create reactive species of the byproduct volatizing gas, wherein the byproduct volatizing gas includes either carbon dioxide (CO2) or carbon monoxide (CO), and wherein the byproduct material is an ammonium salt;
• exposing the byproduct volatizing gas within the lower peripheral open region to reactive species of the plasma while performing the etching to create reactive species of the byproduct volatizing gas within the lower peripheral open region, the reactive species of the byproduct volatizing gas interacting with the byproduct material accumulated within the lower peripheral open region to form a volatile material while performing the etching;
• and
• evacuating the volatile material from the lower peripheral open region through an exhaust gas flow while performing the etching.