Patent ID: 9576815
Date: 2017-02-21
CPC Classifications: H01L

Claim:
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 has an exposed silicon nitride portion and an exposed silicon portion; flowing anhydrous hydrogen fluoride into a remote region fluidly coupled to the substrate processing region through a dual-channel showerhead, wherein the anhydrous HF flows from the remote region to the substrate processing region through a first channel comprising through-holes through the dual-channel showerhead; flowing a hydrogen-and-oxygen-containing precursor into the substrate processing region through a second channel comprising holes which open into the substrate processing region but not directly into the remote region; combining the HF vapor with the hydrogen-and-oxygen-containing precursor in the substrate processing region; and dry etching the exposed silicon nitride portion, wherein the silicon nitride is removed at a silicon nitride etch rate which is greater than a secondary etch rate at which the exposed silicon portion is removed.