Patent ID: 9355856
Filing Date: 2016-05-31
CPC Classification: H01J,H01L

Claim Text:
1. A method of etching a patterned substrate, the method comprising: placing the patterned substrate in a substrate processing region of a substrate processing chamber, wherein the patterned substrate comprises a horizontal Si(100) facet disposed between two adjacent silicon oxide portions; flowing a first halogen-containing precursor into the substrate processing region while forming a local plasma in the substrate processing region to initiate a trench in the horizontal Si(100) facet to form a remaining silicon portion, wherein the first halogen-containing precursor comprises one or more of fluorine, chlorine and bromine; flowing a second halogen-containing precursor into a remote plasma region while forming a remote plasma in the remote plasma region by applying a remote plasma power to produce plasma effluents, wherein the second halogen-containing precursor comprises one or both of chlorine and bromine; flowing the plasma effluents into the substrate processing region through through-holes in a showerhead; and selectively etching the remaining silicon portion to form two Si(111) faces which intersect to form a V-shaped trench, wherein the patterned substrate is not exposed to external atmosphere between placing the patterned substrate into the substrate processing region and selectively etching the remaining silicon portion; and wherein the substrate processing region is plasma-free and fluorine-free during the selectively etching operation.