A two-step method for forming a void free oxide layer on a stepped surface of a semiconductor wafer

摘要

A two step process is disclosed for forming a silicon oxide layer over a stepped surface of a semiconductor wafer while inhibiting the formation of voids in the oxide layer which comprises depositing a layer of an oxide of silicon over a stepped surface of a semiconductor wafer in a CVD chamber by flowing into the chamber a gaseous mixture comprising a source of oxygen, a portion of which comprises O.sub.3, and tetraethylorthosilicate as the gaseous source of silicon while maintaining the pressure in the CVD chamber within a range of from about 250 Torr to about 760 Torr and then depositing a second layer of oxide over the first layer in a CVD chamber by flowing into the chamber a gaseous mixture comprising a source of oxygen, a portion of which comprises O.sub.3 ; and tetraethylorthosilicate as the gaseous source of silicon while maintaining the CVD chamber at a lower pressure than during the first deposition step.