Patent ID: 7998871
Filing Date: 2011-08-16
Classification: H01L,Y10T

Abstract:
1. A method of forming a mask for implanting a substrate, the method comprising the steps of: depositing an implant stopping layer over the substrate, wherein the substrate includes at least one trench isolation; depositing a photoresist over the implant stopping layer, the implant stopping layer having a density and a vertical depth greater than a density and a vertical depth of the photoresist; forming a pattern in the photoresist by wet etching to remove a portion of the photoresist to expose portions of the implant stopping layer; and transferring the pattern into the exposed portions of the implant stopping layer by reactive ion etching using the patterned photomask to form the mask, wherein a portion of the implant stopping layer remains over and abutting the at least one trench isolation after the transferring.