Patent ID: 8298949

Claim:
A method forming spacers from a non-silicon oxide, silicon containing spacer layer with horizontal surfaces and sidewall surfaces over a substrate, comprising: (a) forming a silicon oxide layer over plasma etch chamber surfaces before placing a substrate in the plasma etch chamber; (b) providing a plasma oxidation treatment to form a silicon oxide coating over the spacer layer, wherein the silicon oxide coating provides a horizontal coating on the horizontal surfaces and sidewall coatings on the sidewall surfaces of the spacer layer, wherein the providing the plasma oxidation treatment, comprises: providing an oxygen plasma; and sputtering silicon to form silicon oxide with the oxygen plasma, wherein the plasma oxidation treatment sputters silicon oxide from the plasma etch chamber to provide silicon for the silicon oxide layer formed during the plasma oxidation treatment; (c) providing an anisotropic main etch that selectively etches horizontal surfaces of the spacer layer and silicon oxide coating with respect to sidewall surfaces of the spacer layer and the sidewall coatings of the silicon oxide coating; and (d) etching the spacer layer, wherein the sidewall coatings of the silicon oxide coating protect sidewall surfaces of the spacer layer.