ETCHING SOLUTION, AND METHOD FOR PROCESSING SURFACE OF SINGLE-CRYSTAL SILICON SUBSTRATE

Disclosed is an etching solution which enables the formation of a silicon substrate having fine pyramid-like depressions and protrusions (a textured structure) in a steady manner without requiring the use of any conventional etching inhibitor such as isopropyl alcohol. Specifically disclosed is an etching solution in which a silicon substrate is to be immersed to form pyramid-like depressions and protrusions on the surface of the substrate, and which is characterized by comprising at least one component selected from compounds (A) each represented by general formula (1) and alkali salts thereof and an alkali hydroxide (B) at a concentration of 0.1 to 30 wt% inclusive. (In the formula, R represents one of an alkyl group, an alkenyl group and an alkynyl group each having 4 to 15 inclusive of carbon atoms; and X represents a sulfonic acid group.) By using the etching solution, it becomes possible to form a fine textured structure on the surface of a silicon substrate.