Abstract: Silicon oxide layer is deposited on a semiconductor substrate by PECVD at a temperature of less than about 200° C. and is treated with helium plasma to reduce stress of the deposited layer to an absolute value of less than about 80 MPa. Plasma treatment reduces hydrogen content in the silicon oxide layer, and leads to low stress films that can also have high density and low roughness. In some embodiments, the film is deposited on a semiconductor substrate that contains one or more temperature-sensitive layers, such as layers of organic material or spin-on dielectric that cannot withstand temperatures of greater than 250° C. In some embodiments the silicon oxide film is deposited to a thickness of between about 100-200 ?, and is used as a hardmask layer during etching of other layers on a semiconductor substrate.

Abstract: A method for operating a substrate processing chamber includes after performing a process using a fluorine-based gas in the substrate processing chamber: a) during a first predetermined period, supplying a gas mixture to the substrate processing chamber including one or more gases selected from a group consisting of molecular oxygen, molecular nitrogen, nitric oxide and nitrous oxide and supplying RF power to strike plasma in the substrate processing chamber; b) during a second predetermined period after the first predetermined period, supplying molecular hydrogen gas and RF power to the substrate processing chamber; c) repeating a) and b) one or more times; d) purging the substrate processing chamber with molecular nitrogen gas; e) increasing chamber pressure; f) evacuating the substrate processing chamber; and g) repeating d), e) and f) one or more times.