POLISHING LIQUID, POLISHING LIQUID SET AND POLISHING METHOD

Provided is a CMP polishing liquid used for removing a part of an insulating portion of a base substrate, which includes a substrate, a stopper provided on one surface of the substrate, and the insulating portion provided on a surface of the stopper opposite to the substrate, by CMP to expose the stopper, the polishing liquid containing: abrasive grains containing cerium; a nonionic water-soluble compound A; a polymer compound B having at least one selected from the group consisting of carboxylic acid groups and carboxylate groups; a basic pH adjusting agent which is optionally contained; and water, in which a content of the basic pH adjusting agent is less than 1.3×10−2 mol/kg based on the total mass of the polishing liquid.