Patent ID: 7196014
Filing Date: 2007-03-27
Classification: G03F,H01L

Abstract:
1. A method for improving critical dimension (CD) uniformity of post lithographic structure comprising the step of implementing a dual frequency capacitive plasma etch process for etching a post lithographic structure at process conditions adapted to reduce the root-mean-square (RMS) line edge roughness (LER) of the resulting post lithographic structure, wherein said dual frequency capacitive (DFC) plasma etch process is applied to a spin-on or CVD-type anti-reflective coating (ARC) material underlying a patterned post lithographic structure, said method comprising tailoring a plasma etch chemistry such that a significant neutral to ion flux ratio of chemically reactive species is achieved whereby a rate of chemisorption of the reactive species onto an ARC material surface is greater than a rate of sputtering of volatile adsorbates from the surface thereby facilitating increased etch isotropy and resulting in reduced CD non-uniformity and uniform line width variation.