Method for processing substrate, chemical solution, and method for providing chemical solution

A method for processing a substrate, for processing a surface of a substrate having projections/depressions formed on the surface, the method comprising:

• a rinsing step of rinsing the surface of the substrate with a rinsing solution containing water;
• a chemical solution replacement step of bringing a chemical solution into contact with the surface of the substrate that has been rinsed, to replace a liquid adhering to the surface of the substrate from the rinsing solution to the chemical solution;
• a state change step of raising a temperature of the substrate wetted with the chemical solution to a temperature equal to or higher than a critical temperature of the chemical solution to allow the chemical solution to reach a supercritical state;
• and
• a removing step of removing the chemical solution in the supercritical state from the surface of the substrate,
• wherein the chemical solution contains an organic solvent (S1) having a higher specific gravity than water, provided that the organic solvent (S1) excludes organic solvents having a fluorine atom, and
• the organic solvent (S1) includes at least one solvent selected from the group consisting of carbonate solvents and lactone solvents.