Cleaning fluid and cleaning method

A cleaning liquid for a semiconductor substrate that has been subjected to a chemical mechanical polishing treatment, the cleaning liquid comprising:

• a component A having two or more onium structures in a molecule;
• and
• water,
• wherein the cleaning liquid has a pH of 7.0 to 11.8 at 25° C., and
• the component A is at least one selected from the group consisting of a compound represented by General Formula (I), a compound represented by General Formula (II), and a compound having two or more sulfonium structures,
• in General Formula (I), R1 to R6 each independently represent a monovalent organic group, two of R1 to R6 may be bonded to each other, L1 represents a divalent linking group which is an aromatic hydrocarbon group, or a group formed by combination of an aliphatic hydrocarbon group and an aromatic hydrocarbon group, the divalent linking group optionally has —S—, —S(═O)2—, —O—, —C(═O)—, or a group formed by a combination of two or more of these groups, instead of a methylene group comprised in the aliphatic hydrocarbon group, n represents 1 or 2, and X(2/n)− represents a (2/n)-valent counterion,
• in General Formula (II), R7 to R12 each independently represent a monovalent organic group, two of R7 to R12 may be bonded to each other, L2 represents a divalent linking group which is an aromatic hydrocarbon group, or a group formed by combination of an aliphatic hydrocarbon group and an aromatic hydrocarbon group, the divalent linking group optionally has —S—, —S(═O)2—, —O—, —C(═O)—, or a group formed by a combination of two or more of these groups, instead of a methylene group comprised in the aliphatic hydrocarbon group, n represents 1 or 2, and X(2/n)− represents a (2/n)-valent counterion.