Salt, acid generator, resist composition and method for producing resist pattern
A salt represented by formula (I) and a resist composition including the salt are described. wherein, in formula (I), Q 1 and Q 2 each independently represent a fluorine atom or the like, R 1 and R 2 each independently represent a hydrogen atom or the like, Z represents an integer of 0 to 6, X 1 represents *—CO—O—, *—O—CO—, *—O—CO—O— or *—O—, L 1 represents a single bond or an alkanediyl group having 1 to 6 carbon atoms, A 1 represents a divalent cyclic hydrocarbon group having 3 to 36 carbon atoms which may have a substituent, L 2 represents a single bond, a carbonyl group or an alkanediyl group having 1 to 6 carbon atoms, A 2 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms which may have a substituent, R 3 , R 4 and R 5 each independently represent a saturated hydrocarbon group having 1 to 6 carbon atoms, and Z + represents an organic cation.
1. A resist composition comprising:
an acid generator,
a resin having an acid-labile group, and
a salt generating a carboxylic acid having an acidity lower than that of an acid generated from the acid generator,
wherein the acid generator comprises a salt represented by formula (I), and the resin having an acid-labile group includes a structural unit represented by formula (a2-A):
wherein, in formula (I),
Q 1 and Q 2 each independently represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms,
R 1 and R 2 each independently represent a hydrogen atom, a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms,
z represents an integer of 0 to 6 and when z is 2 or more, a plurality of R 1 and R 2 may be the same or different from each other,
X 1 represents *—CO—O—, *—O—CO—, *—O—CO—O— or *—O—, and * represents a bonding site to C(R 1 ) (R 2 ) or C(Q 1 ) (Q 2 ),
L 1 represents a single bond or an alkanediyl group having 1 to 6 carbon atoms,
A 1 represents a divalent alicyclic saturated hydrocarbon group having 3 to 36 carbon atoms which may have a substituent, and —CH 2 —included in the alicyclic saturated hydrocarbon group may be replaced by —O—, —S—, —CO— or —SO 2 —,
L 2 represents a single bond, a carbonyl group or an alkanediyl group having 1 to 6 carbon atoms,
A 2 represents a divalent saturated hydrocarbon group which is: (i) an alkanediyl group having 1 to 24 carbon atoms which may have a substituent, (ii) an alicyclic saturated hydrocarbon group having 3 to 24 carbon atoms which may have a substituent of a halogen atom, a cyano group, a carboxy group, an alkoxy group having 1 to 12 carbon atoms, or a group obtained by combining two or more of these groups, or (iii) a group formed by combining two or more of (i) and (ii),
R 3 , R 4 and R 5 each independently represent a saturated hydrocarbon group having 1 to 6 carbon atoms, and
Z + represents an organic cation;
wherein, in formula (a2-A),
R a50 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom,
R a51 represents a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, an acryloyloxy group or a methacryloyloxy group,
A a50 represents a single bond or *—X a51 —(A a52 —X a52 ) nb— ,and * represents a bonding site to a carbon atom to which —R a50 is bonded,
A a52 represents an alkanediyl group having 1 to 6 carbon atoms,
X a51 and X a52 each independently represent —O—, −CO—O— or —O—CO—,
nb represents 0 or 1, and
mb represents an integer of 0 to 4, and when mb is an integer of 2 or more, a plurality of R a51 may be the same or different from each other.
2. The resist composition according to claim 1 , wherein A 1 is a divalent norbornane lactone group or an adamantanediyl group.
3. The resist composition according to claim 1 , wherein A 2 is an alkanediyl group having 1 to 6 carbon atoms.
4. The resist composition according to claim 1 , wherein the resin having an acid-labile group includes at least one selected from the group consisting of a structural unit represented by formula (a1-1) and a structural unit represented by formula (a1-2):
wherein, in formula (a1-1) and formula (a1-2),
L a1 and L a2 each independently represent —O— or *—O—(CH 2 ) k1 —CO—O—, k1 represents an integer of 1 to 7, and * represents a bonding site to —CO—,
R a4 and R a5 each independently represent a hydrogen atom or a methyl group,
R a6 and R a7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group obtained by combining these groups,
m1 represents an integer of 0 to 14,
n1 represents an integer of 0 to 10, and
n1′ represents an integer of 0 to 3.
5. The resist composition according to claim 1 , further comprising a resin including a structural unit having a fluorine atom.
6. The resist composition according to claim 1 , wherein the substituent possessed by the divalent alicyclic saturated hydrocarbon group of A 1 is a halogen atom, a hydroxy group, a cyano group, a carboxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a group obtained by combining two or more of these groups.
7. The resist composition according to claim 1 , wherein R 1 and R 2 represent a hydrogen atom, and z represents an integer of 0 to 2.
8. The resist composition according to claim 1 , wherein L 2 represents a carbonyl group.
9. A method for producing a resist pattern, which comprises:
(1) a step of applying the resist composition according to claim 1 on a substrate,
(2) a step of drying the applied composition to form a composition layer,
(3) a step of exposing the composition layer,
(4) a step of heating the exposed composition layer, and
(5) a step of developing the heated composition layer.