Cleaning composition for semiconductor substrate and cleaning method
A cleaning composition for a semiconductor substrate contains a solvent, and a polymer that includes a fluorine atom, a silicon atom or a combination thereof. The content of water in the solvent is preferably no greater than 20% by mass. The cleaning composition preferably further contains an organic acid which is a non-polymeric acid. The organic acid is preferably a polyhydric carboxylic acid. The acid dissociation constant of the polymer is preferably less than that of the organic acid. The solubility of the organic acid in water at 25° C. is preferably no less than 5% by mass. The organic acid is preferably a solid at 25° C.
1. A cleaning composition comprising:
a solvent;
a polyhydric carboxylic acid; and
a polymer comprising a fluorine atom or a combination of fluorine and silicon atoms, and comprising a structural unit represented by formula (1-1), a structural unit represented by formula (1-2), or a combination thereof,
wherein, in the formulae (1-1) and (1-2), each Rf independently represents a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms, the monovalent fluorinated hydrocarbon group comprising a group represented by formula (i), and in a case where Rf is present in a plurality of number, a plurality of Rfs are identical or different,
in the formula (1-1), m is an integer of 1 to 3; R 1 represents a hydrogen atom, a fluorine atom, a methyl group or —COOR′; R′ represents a monovalent hydrocarbon group having 1 to 20 carbon atoms; R 2 represents a single bond, —O—, —CO—, —COO— or —CONH—; and in a case of m is 1, R 3 represents a single bond, a divalent organic group having 1 to 20 carbon atoms, and in the case where m is 2 or 3, R 3 represents an organic group having 1 to 20 carbon atoms and having a valency of (m+1), and
in the formula (1-2), n is an integer of 1 to 3; R 2′ represents a single bond, —O—, —COO— or —CONH—; and in a case where n is 1, R 3′ represents a single bond or a divalent organic group having 1 to 20 carbon atoms, and in a case where n is 2 or 3, R 3′ represents an organic group having 1 to 20 carbon atoms and having a valency of (n+1),
wherein in the formula (i), R A and R B each independently represent a hydrogen atom, a fluorine atom, an alkyl group having 1 to 8 carbon atoms or a fluorinated alkyl group having 1 to 8 carbon atoms, wherein at least either one of R A or R B represents a fluorine atom or a fluorinated alkyl group having 1 to 8 carbon atoms; and * denotes a binding site to an atom of the polymer,
wherein when the polymer comprises a structural unit comprising a silicon atom, the structural unit comprising a silicon is at least one structural unit selected from the group consisting of:
2. The cleaning composition according to claim 1 , wherein a content of water in the solvent is no greater than 20% by mass.
3. The cleaning composition according to claim 1 , wherein the polymer does not comprise an acid group, or the polymer comprises an acid group and an acid dissociation constant of the polymer is smaller than an acid dissociation constant of the polyhydric carboxylic acid.
4. The cleaning composition according to claim 1 , wherein a solubility of the polyhydric carboxylic acid in water at 25° C. is no less than 5% by mass.
5. The cleaning composition according to claim 1 , wherein the polyhydric carboxylic acid is a solid at 25° C.
6. The cleaning composition according to claim 1 , wherein a total content of the fluorine atom and the silicon atom in the polymer is 15% by mass or more, and
a content of the polymer with respect to a total solid content in the cleaning composition is 30% by mass or more.
7. The cleaning composition according to claim 1 , wherein a content of the polyhydric carboxylic acid in the cleaning composition is 0.05% by mass or more.
8. The cleaning composition according to claim 1 , wherein a content of the polyhydric carboxylic acid in the cleaning composition is 0.1% by mass or more.
9. The cleaning composition according to claim 1 , wherein a content of the polyhydric carboxylic acid with respect to a total solid content in the cleaning composition is 30% by mass or less.
10. The cleaning composition according to claim 1 , wherein a content of the polyhydric carboxylic acid with respect to a total solid content in the cleaning composition is 10% by mass or less.
11. The cleaning composition according to claim 1 , wherein the polyhydric carboxylic acid is at least one selected from the group consisting of oxalic acid, malic acid and citric acid.
12. The cleaning composition according to claim 1 , wherein a content of the polymer with respect to a total solid content in the cleaning composition is preferably 50% by mass or more.
13. The cleaning composition according to claim 1 , wherein a molecular weight of the polyhydric carboxylic acid is 300 or less.
14. The cleaning composition according to claim 1 , wherein a content of water in the solvent is no greater than 2% by mass.
15. The cleaning composition according to claim 1 , wherein the solvent does not contain water.
16. The cleaning composition according to claim 1 , wherein content of the solvent in the cleaning composition is from 80% by mass to 99.5% by mass.
17. The cleaning composition according to claim 1 , wherein content of the solvent in the cleaning composition is from 90% by mass to 99.0% by mass.