Patent ID: 9012289
Filing Date: 2015-04-21
Classification: H01L

Abstract:
1. A method of manufacturing a semiconductor device, comprising the following steps: providing a semiconductor substrate, forming a patterned dielectric layer on the substrate, the patterned dielectric layer having an opening therein exposing a portion of an upper surface of the substrate; forming a first gate dielectric layer and a mask layer of dielectric material on the first gate dielectric layer, said first gate dielectric layer and said mask layer conforming with the patterned dielectric layer and the opening on the substrate; etching the mask layer to retain at least a portion of the mask layer on the first gate dielectric layer within the opening so that a residual of the mask layer is located within the opening and is attached to the first gate dielectric layer at a sidewall of the opening; etching the first gate dielectric layer using the residual of the mask layer of dielectric material to expose a portion of the substrate within the opening; and forming a second gate dielectric layer on the exposed substrate portion, wherein the thickness of the second gate dielectric layer is less than that of the first gate dielectric layer.