Patent ID: 8586486

Claim:
A method comprising: (a) treating a material layer above a semiconductor substrate with plasma oxygen; (b) depositing a layer of photoresist over a first surface of the material layer after the treating of the material layer; (c) patterning the layer of photoresist, thereby forming a patterned photoresist and exposing portions of the material layer; (d) etching the exposed portions of at least the material layer to form at least one contact via in the material layer extending to a source or drain region or gate electrode of a device at a surface of the substrate; and (e) removing the patterned photoresist from the first surface of the material layer; wherein an etch stop layer is disposed beneath the material layer, and a bottom surface of the at least one contact via extends at least to a top surface of the etch stop layer; the etch stop layer emits a contaminant while etching the exposed portions of at least the material layer, and treating the first surface of the material layer results in oxidation of the first surface; the at least one contact via further comprises sidewalls, and the contaminant causes formation of photoresist scum on the sidewalls and bottom surface of the at least one contact via; and treating the first surface of the material layer with plasma oxygen prevents the photoresist scum from remaining on the sidewalls and bottom surface of the at least one contact via.