Patent ID: 8946002
Filing Date: 2015-02-03
Classification: H01L

Abstract:
1. A method of forming an insulated gate semiconductor device comprising the steps of: providing a region of semiconductor material having a major surface; forming a first trench extending from the major surface into the region of semiconductor material; forming a first dielectric layer overlying surfaces of the first trench; forming a photosensitive layer overlying the first dielectric layer; exposing the photosensitive layer to an energy source to form a soluble portion of the photosensitive layer and a non-soluble portion of the photosensitive layer, wherein the soluble portion is adjacent at least a portion of the first dielectric layer on at least one upper sidewall surface of the first trench; removing the soluble portion in a solution to expose the first dielectric layer on at least one upper sidewall surface of the first trench; removing the exposed portion of the first dielectric layer from the at least one upper sidewall surface of the first trench; removing the non-soluble portion of the photosensitive layer; forming a second dielectric layer along the at least one upper sidewall surface, wherein the first and second dielectric layers have different thicknesses; and forming a first conductive electrode along at least one of the first and second dielectric layers.