Composition for surface treatment, method for producing the same, surface treatment method using composition for surface treatment, and method for producing semiconductor substrate

A composition for surface treatment comprising:

• a polymer compound having at least one ionic functional group selected from the group consisting of a sulfonic acid (salt) group, a phosphoric acid (salt) group, and a phosphonic acid (salt) group;
• and
• water, wherein;
• when the ionic functional group is the sulfonic acid salt group, the sulfonic acid salt group is at least one selected from the group consisting of a sulfonic acid alkali metal salt and a sulfonic acid salt of a group bold 2 element;
• when the ionic functional group is the phosphoric acid salt group, the phosphoric acid salt group is a phosphoric acid metal salt;
• and
• when the ionic functional group is the phosphonic acid salt group, the phosphonic acid salt group is at least one selected from the group consisting of a phosphonic acid alkali metal salt and a phosphonic acid salt of a group 2 element,
• a pH of the composition is less than 7, and
• the polymer compound has a pKa of 3 or less and an ionic functional group density of more than 10%, wherein the ionic functional group density is represented by the following formula (1):
• Ionic functional group density (%)=100×(Number of constituent unit derived from monomer having ionic functional group/Number of constituent unit derived from all monomers constituting polymer compound) Formula (1).