Etching solution, method for treating substrate with the etching solution, and method for manufacturing semiconductor device

Abstract

Silicon carbonitride with excellent dielectric and/or other properties may be used in manufacturing semiconductor devices. The manufacturing often requires etching silicon carbonitride without etching silicon oxide, but there is no known etching solution that sufficiently selectively etches silicon carbonitride containing carbon compared with silicon nitride used for the same purpose. An object of the present invention is to provide: an etching solution with a high etching selectivity ratio of silicon carbonitride to silicon oxide; a method of treating a substrate, the method including a step of bringing the etching solution into contact with the substrate; and a method of manufacturing a semiconductor device, the method including the method of treating a substrate. The object is achieved by an etching solution for etching silicon carbonitride, the etching solution composed of a homogeneous solution containing phosphoric acid, water, and a cerium ion.