Etching solution

Abstract

This invention provides an etching solution in a single-state sample that can suppress the etching of silicon oxide (SiO2) and polycrystalline silicon (Poly-Si), and selectively etch silicon nitride (SiN) or silicon carbonitride (SiCN). The single-state sample of this invention relates to an etching solution prepared by mixing phosphoric acid (component A), silicon dioxide (component B), a silane compound represented by formula (I) below (component C), a fluorine compound (component D), and water (component E), wherein the mass ratio of component C to component B, C / B, is 300 or less.