Patent ID: 9576788
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, wherein the patterned substrate has a high aspect ratio via having a height-to-width aspect ratio greater than 25:1; flowing a fluorine-containing precursor into a remote plasma region while forming a remote plasma in the remote plasma region to produce plasma effluents; flowing the plasma effluents through a first showerhead and into an intershowerhead region between the first showerhead and a second showerhead; combining the plasma effluents with a nitrogen-and-hydrogen-containing precursor in the intershowerhead region, wherein the nitrogen-and-hydrogen-containing precursor has not been passed through any plasma to form a precursor combination; flowing the precursor combination through the second showerhead into the substrate processing region; forming a local plasma in the substrate processing region; and removing an exposed portion of silicon oxide from the bottom of the high aspect ratio via.