Radiation-sensitive resin composition, polymer and method for forming a resist pattern

1. A radiation-sensitive resin composition comprising:

a first polymer comprising:

a structure unit represented by formula (1-1), a structure unit represented by formula (1-2), or both thereof; and

a structure unit represented by formula (2-2), a structure unit represented by formula (2-3), or both thereof,

the first polymer having a content of fluorine atoms of no less than 5% by mass to a total mass of the first polymer;

a second polymer comprising an acid-dissociable group, and having a content of fluorine atoms of less than 5% by mass to a total mass of the second polymer; and

a radiation-sensitive acid generator,

wherein, in the formulae (1-1) and (1-2),

each R 1 independently represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group,

wherein, in the formula (1-1),

Y represents CH;

R 2 and R 3 each independently represent an alkyl group, and optionally R 2 and R 3 bind with each other to form an alicyclic structure together with Y;

R 4 represents an alkyl group, an alkoxy group, an acyl group or an acyloxy group;

in a case where R 4 is present in a plurality of number, the plurality of R 4 are a same or different with each other;

a part or all of hydrogen atoms of R 4 are substituted or unsubstituted;

a is 1 or 2; and

b is an integer of 0 to 3, and

wherein, in the formula (1-2),

R 5 represents an alkyl group;

R 6 represents an alkyl group, an alkoxy group, an acyl group or an acyloxy group;

in a case where R 6 is present in a plurality of number, the plurality of R 6 are a same or different;

a part or all of hydrogen atoms of R 6 are substituted or unsubstituted;

e is 1 or 2; and

f is an integer of 0 to 5,

wherein, in the formulae (2-2) and (2-3),

R 1 represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group,

wherein in the formula (2-2),

R 7 represents a linking group having a valency of (g+1);

R 8 represents an alkali-dissociable monovalent organic group, the alkali-dissociable monovalent organic group being a group that substitutes for a hydrogen atom in a polar functional group and that dissociates in a presence of an alkali;

in a case where R 8 is present in a plurality of number, the plurality of R 8 are a same or different;

Rf 2 and Rf 3 each independently represent a hydrogen atom, a fluorine atom or a fluorinated hydrocarbon group having 1 to 30 carbon atoms, wherein at least one of Rf 2 and Rf 3 does not represent a hydrogen atom;

in a case where Rf 2 or Rf 3 is present in a plurality of number, the plurality of Rf 2 and Rf 3 are each a same or different; and

g is an integer of 2 or 3, and

wherein, in the formula (2-3),

R 9 represents a bivalent linking group;

R 10 represents a hydrogen atom or a monovalent organic group; and

Rf 4 and Rf 5 each independently represent a hydrogen atom, a fluorine atom or a fluorinated hydrocarbon group having 1 to 30 carbon atoms, wherein at least one of Rf 4 and Rf 5 does not represent a hydrogen atom.

2. The radiation-sensitive resin composition according to claim 1 , wherein the first polymer further comprises a structure unit, except for the structure unit represented by the formula (2-3), that comprises a group represented by formula (4-1), a group represented by formula (4-2), or both thereof,

wherein in the formula (4-1),

R 41 represents a hydrocarbon group having 1 to 10 carbon atoms substituted with a fluorine atom.

3. The radiation-sensitive resin composition according to claim 1 , wherein a content of the first polymer with respect to 100 parts by mass of the second polymer is no less than 0.1 parts by mass and no greater than 20 parts by mass.

4. A polymer comprising:

a structure unit represented by formula (1-1), a structure unit represented by formula (1-2) or both thereof; and

a structure unit represented by formula (2-2), a structure unit represented by formula (2-3), or both thereof,

the polymer having a content of fluorine atoms of no less than 5% by mass to a total mass of the first polymer,

wherein, in the formulae (1-1) and (1-2),

each R 1 independently represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group,

wherein in the formula (1-1),

Y represents CH;

R 2 and R 3 each independently represent an alkyl group, and optionally R 2 and R 3 bind with each other to form an alicyclic structure together with Y;

R 4 represents an alkyl group, an alkoxy group, an acyl group or an acyloxy group;

in a case where R 4 is present in a plurality of number, the plurality of R 4 are a same or different with each other;

a part or all of hydrogen atoms of R 4 are substituted or unsubstituted;

a is 1 or 2; and

b is an integer of 0 to 3, and

wherein in the formula (1-2),

R 5 represents an alkyl group;

R 6 represents an alkyl group, an alkoxy group, an acyl group or an acyloxy group;

in a case where R 6 is present in a plurality of number, the plurality of R 6 are a same or different;

a part or all of hydrogen atoms of R 6 are substituted or unsubstituted;

e is 1 or 2; and

f is an integer of 0 to 5,

wherein, in the formulae (2-2) and (2-3),

R 1 represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group,

wherein in the formula (2-2),

R 7 represents a linking group having a valency of (g +1);

R 8 represents an alkali-dissociable monovalent organic group, the alkali-dissociable monovalent organic group being a group that substitutes for a hydrogen atom in a polar functional group and that dissociates in a presence of an alkali;

in a case where R 8 is present in a plurality of number, the plurality of R 8 are a same or different;

Rf 2 and Rf 3 each independently represent a hydrogen atom, a fluorine atom or a fluorinated hydrocarbon group having 1 to 30 carbon atoms, wherein at least one of Rf 2 and Rf 3 does not represent a hydrogen atom;

in a case where Rf 2 or Rf 3 is present in a plurality of number, the plurality of Rf 2 and Rf 3 are each a same or different; and

g is an integer of 2 or 3, and

wherein, in the formula (2-3),

R 9 represents a bivalent linking group;

R 10 represents a hydrogen atom or a monovalent organic group; and

Rf 4 and Rf 5 each independently represent a hydrogen atom, a fluorine atom or a fluorinated hydrocarbon group having 1 to 30 carbon atoms, wherein at least one of Rf 4 and Rf 5 does not represent a hydrogen atom.

5. The polymer according to claim 4 further comprising: a structure unit, except for the structure unit represented by the formula (2-3), that comprises a group represented by formula (4-1), a group represented by formula (4-2), or both thereof,

wherein, in the formula (4-1),

R 41 represents a hydrocarbon group having 1 to 10 carbon atoms substituted with a fluorine atom.

6. A method for forming a resist pattern, comprising:

forming a photoresist film on a substrate using the radiation-sensitive resin composition according to claim 1 ;

subjecting the photoresist film to liquid immersion lithography through a liquid for immersion lithography disposed on the photoresist film; and

developing the photoresist film subjected to liquid immersion lithography to form a resist pattern.

7. A method for forming a resist pattern, comprising:

forming a photoresist film on a substrate using the radiation-sensitive resin composition according to claim 2 ;

subjecting the photoresist film to liquid immersion lithography through a liquid for immersion lithography disposed on the photoresist film; and

developing the photoresist film subjected to liquid immersion lithography to form a resist pattern.

8. A method for forming a resist pattern, comprising:

forming a photoresist film on a substrate using the radiation-sensitive resin composition according to claim 3 ;

subjecting the photoresist film to liquid immersion lithography through a liquid for immersion lithography disposed on the photoresist film; and

developing the photoresist film subjected to liquid immersion lithography to form a resist pattern.

9. The radiation-sensitive resin composition according to claim 2 , wherein the structure unit that comprises a group represented by formula (4-1), a group represented by formula (4-2), or both thereof is derived from a methacrylic acid ester, an acrylic acid ester, or an α-trifluoroacrylic acid ester.

10. The polymer according to claim 5 , wherein the structure unit that comprises a group represented by formula (4-1), a group represented by formula (4-2), or both thereof is derived from a methacrylic acid ester, an acrylic acid ester, or an α-trifluoroacrylic acid ester.

11. The radiation-sensitive resin composition according to claim 1 , wherein the first polymer comprises the structure unit represented by the formula (1-2).

12. The polymer according to claim 4 , wherein the polymer comprises the structure unit represented by the formula (1-2).

13. The radiation-sensitive resin composition according to claim 1 , wherein the first polymer comprises the structure unit represented by the formula (2-3).

14. The polymer according to claim 4 , wherein the polymer comprises the structure unit represented by the formula (2-3).