Gas-phase silicon nitride selective etch

摘要

A method of etching silicon nitride on patterned heterogeneous structures is described and includes a gas phase etch using anhydrous vapor-phase HF. The HF may be combined with one or more of several precursors in the substrate processing region and near the substrate to increase the silicon nitride etch rate and/or the silicon nitride selectivity. The silicon nitride etch selectivity is increased most notably when compared with silicon of various forms. No precursors are excited in any plasma either outside or inside the substrate processing region according to embodiments. The HF may be flowed through one set of channels in a dual-channel showerhead while the other precursor is flowed through a second set of channels in the dual-channel showerhead.

主权项

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.