Patent ID: 8808563

Claim:
A method of etching a patterned substrate in a substrate processing region of a substrate processing chamber, wherein the patterned substrate has exposed silicon, the method comprising: flowing each of a fluorine-containing precursor and a hydrogen-containing precursor into a remote plasma region fluidly coupled to the substrate processing region while forming a remote plasma in the remote plasma region to produce plasma effluents, wherein an atomic flow ratio of hydrogen (H) to fluorine (F) is greater than or about 25:1 and forming the remote plasma in the remote plasma region to produce the plasma effluents comprises applying an RF plasma having an RF plasma power to the plasma region; and etching the exposed silicon by flowing the plasma effluents into the substrate processing region through through-holes in a showerhead, wherein a temperature of the patterned substrate during the etching operation is greater than or about 0° C. and a pressure within the substrate processing region is above or about 0.05 Torr and below or about 10 Torr.