Plasma pre-treatment for improved uniformity in semiconductor manufacturing

A method for forming a semiconductor device, said method comprising:

• forming a photoresist pattern over a material disposed on a substrate;
• and
• etching by performing a sequence of plasma processing operations including a plasma treatment operation, a breakthrough operation, an etch operation, and an overetch operation,
• said plasma treatment operation including a pressure less than about 20 millitorr and a total O2 and Cl2 flow rate in a range of about 40-90 sccm in which said O2 flow rate comprises about 30-55% of said total flow rate.

A method for forming a semiconductor device, said method comprising:

• forming a photoresist pattern over a material disposed on a substrate;
• performing a plasma treatment operation that reduces critical dimensions (CDs) of features of said photoresist pattern to a greater extent at a first portion of said substrate than at a second portion of said substrate, thereby forming a treated pattern;
• etching said material using said treated pattern as a photomask thereby creating etched features;
• and
• after said etching, using an overetch operation that reduces CDs of said etched features of said material to a greater extent at said second portion of said substrate than at said first portion of said substrate.