Patent ID: 8501629

Claim:
A method of etching a silicon-containing layer on a surface of a substrate in a substrate processing region of a substrate processing chamber, wherein the method leaves a relatively smooth post-etch surface, the method comprising: flowing a fluorine-containing precursor and a hydrogen-containing precursor into a first remote plasma region fluidly coupled to the substrate processing region while forming a plasma in the first plasma region to produce plasma effluents, wherein a flow rate of the fluorine-containing precursor and a flow rate of the hydrogen-containing precursor result in a hydrogen-to-fluorine atomic flow ratio of less than 1:2; etching the silicon-containing layer by flowing the plasma effluents into the substrate processing region while forming solid by-products on the surface of the substrate; and sublimating the solid by-products to leave the relatively smooth post-etch surface by increasing a temperature of the substrate above a sublimation temperature of the solid by-products.