主权项 |
1. A method of etching tungsten, the method comprising:
transferring a patterned substrate into a substrate processing region, wherein the patterned substrate has a tungsten lining layer coating a high aspect ratio trench having a depth more than five times a width of the high aspect ratio trench; flowing a first fluorine-containing precursor into the substrate processing region while applying a bias plasma power to bombard the patterned substrate with fluorine-containing ions; flowing a second fluorine-containing precursor into a remote plasma region fluidly coupled to a substrate processing region via perforations in a perforated plate; forming a remote plasma in the remote plasma region to produce plasma effluents from the second fluorine-containing precursor and flowing the plasma effluents into the substrate processing region through the perforations; and etching the tungsten lining layer, wherein, after etching the tungsten lining layer, a top sidewall thickness of the tungsten lining layer measured on a sidewall of the high aspect ratio trench near the opening of the high aspect ratio trench is within 20% of a bottom sidewall thickness of the tungsten lining layer measured on the sidewall of the high aspect ratio trench near the bottom of the high aspect ratio trench. |