| CPC H01L 21/32134 (2013.01) [C09K 13/00 (2013.01); C09K 13/04 (2013.01); H01L 21/31105 (2013.01); H01L 21/31111 (2013.01)] | 7 Claims |
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1. A method of treating a substrate, the method comprising a step of bringing an etching solution into contact with a substrate comprising a silicon oxide film and a silicon carbonitride film, wherein the etching solution is composed of a homogeneous solution comprising phosphoric acid, water, and a cerium ion, wherein a content of a tetravalent cerium ion contained in the etching solution is 0.001 mol/L or greater and 0.2 mol/L or less.
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