Patent ID: 9666472
Date: 2017-05-30
CPC Classifications: H01L

Claim:
1. A method for controlling a critical dimension of shallow trench isolations in a STI etch process, wherein the STI etch process comprises the steps of: forming a hard mask layer on a substrate in which active areas are formed, forming a bottom anti-reflective coating layer on the hard mask layer by spin coating, coating a photoresist on the bottom anti-reflective coating layer and patterning to form a photoresist pattern covering the active areas with a target critical dimension, etching the bottom anti-reflective coating layer and the hard mask layer by using the photoresist pattern as a mask according to an etch process recipe and then removing the photoresist pattern and the bottom anti-reflective coating layer, performing a trimming process to the hard mask layer to form a hard mask pattern having a required post-etch critical dimension which is equal to a critical dimension of the active areas, and etching the substrate by using the hard mask pattern as a mask to form the shallow trenches; the method comprises following two steps: Step S Step S