Patent ID: 8748322

Claim:
A method of etching gapfill silicon oxide from a narrow trench on a patterned substrate in a substrate processing region of a substrate processing chamber, the method comprising: flowing a treatment gas into the substrate processing region; forming a local plasma from the treatment gas in the substrate processing region, wherein the local plasma is formed by applying a local plasma power and a treatment pressure is maintained in the substrate processing region; treating the patterned substrate with the local plasma; combining a hydrogen-containing precursor and a fluorine-containing precursor in a remote plasma region while forming a remote plasma in the remote plasma region to form plasma effluents, wherein the remote plasma is formed by applying a remote plasma power; flowing the plasma effluents into the substrate processing region; etching the gapfill silicon oxide below the top of the trench, wherein etching the gapfill silicon oxide occurs after the operation of treating the patterned substrate.