Patent ID: 8999829
Filing Date: 2015-04-07
Classification: H01L

Abstract:
1. A method of forming two gates on a patterned substrate, the method comprising the sequential steps of: (a) providing a patterned substrate having a patterned silicon-and-nitrogen-containing layer over a patterned thick gate dielectric layer formed over a semiconductor material, wherein the patterned substrate comprises a first trench and a second trench which each have a first thickness of thick gate dielectric material of the patterned thick gate dielectric layer; (b) forming a conformal hardmask layer over the patterned substrate; (c) forming a photoresist layer over the patterned substrate; (d) patterning the conformal hardmask layer and the photoresist layer to expose the thick gate dielectric layer in the second trench but leaving the thick gate dielectric layer in the first trench protected; (e) etching the thick gate dielectric material from the second trench to expose the semiconductor material; (f) removing the remaining conformal hardmask layer by exposing the remaining conformal hard mask layer to a plasma; and forming a thin gate dielectric layer on the exposed semiconductor material, wherein the thin gate dielectric layer has a second thickness, different from the first thickness.