Patent ID: 7772121

Claim:
A method of forming a trench structure, comprising: positioning a substrate having high aspect ratio features in a deposition chamber; ionizing one or more chemical etch species selected from the group comprising sulfur hexafluoride (SF 6 ), carbon tetrachloride (CCl 4 ), trifluoromethane (CHF 3 ), difluoromethane (CH 2 F 2 ), and fluorochloromethane (CH 2 FCl) in a remote chamber by a remote power source; providing a gas mixture to the deposition chamber, wherein the gas mixture comprises one or more process gases and the one or more ionized chemical etch species, wherein the one or more ionized chemical etch species are provided into the deposition chamber in a collimated manner; and depositing an oxide layer on the substrate from the one or more process gases, wherein the ionized chemical etch species in the gas mixture selectively remove portions of a material layer deposited adjacent to the high aspect ratio features.