Patent ID: 6319777
Filing Date: 2001-11-20
Classification: H01L

Abstract:
A method of manufacturing a semiconductor device having an electrode provided in an insulated trench, trench walls of which are lined with a lower insulating layer in a lower part of the trench and with a thicker upper insulating layer in an upper part of the trench, wherein the insulated trench is formed by process steps that include:(a) etching the trench into a semiconductor body from one surface of the body,(b) providing the lower insulating layer on the trench walls,(c) depositing on the lower insulating layer a further layer of a different material from that of the lower insulating layer,(d) depositing on the further layer a filler material that is of a different material from the further layer,(e) etching away the further layer from the upper part of the trench walls while using the filler material as an etchant mask, so as to form a space adjacent to the upper part of the trench walls while leaving the further layer in the lower part of the trench, and(f) providing the thicker upper insulating layer in the space adjacent to the upper part of the trench walls.