Method of forming shallow trench isolation using antireflection layer

Abstract

Shallow trench isolation among transistors and other devices on a semiconductor substrate is provided by initially forming a layer of highly absorbing silicon rich nitride to serve as a hardmask between a semiconductor substrate and a photoresist. The highly absorbing layer of silicon rich nitride has an extinction coefficient (k)>0.5. As reflected light passes through the layer of silicon rich nitride, a substantially amount of light is absorbed therein thereby blocking such reflected light from negatively interfering with patterning of the photoresist during photo-lithography. Following patterning of the photoresist, isolation trenches are formed in the semiconductor substrate by etching through the silicon rich nitride in accordance with the pattern formed on the photoresist.

Dependencies are inferred from the claim text.