Photoresist composition and resist pattern-forming method
A photoresist composition includes a polymer that includes a first structural unit shown by a formula (1), and an acid generator. R 1 represents a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 2 represents a divalent hydrocarbon group having 1 to 10 carbon atoms. A represents —COO—*, —OCO—*, —O—, —S—, or —NH—, wherein “*” indicates a site bonded to R 3 . R 3 represents a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms. The polymer preferably further includes a second structural unit that includes an acid-labile group.
1. A photoresist composition comprising:
a polymer that comprises:
a first structural unit shown by formula (1);
a second structural unit comprising an acid-labile group and shown by formula (2); and
a third structural unit comprising a lactone group, a cyclic carbonate group, a sultone group, or a combination thereof, and being other than the first structural unit; and
an acid generator,
wherein
R 1 represents a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group,
R 2 represents a divalent hydrocarbon group having 1 to 10 carbon atoms,
A represents —COO—*, —OCO—*, —O—, —S—, or —NH—, wherein “*” indicates a site bonded to R 3 , and
R 3 represents a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms, R 3 being bonded to a carbon atom at a position other than a bridgehead position of the 5-oxo-4-oxatricyclo[4.3.1.1 3,8 ]undecane structure in the formula (1),
wherein
R 4 represents a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group, and
R 5 to R 7 independently represent a linear or branched alkyl group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 4 to 20 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms, or
R 5 represents a linear or branched alkyl group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 4 to 20 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms, and R 6 and R 7 taken together represent a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms together with the carbon atom bonded to R 6 and R 7 ,
wherein a content of the first structural unit in the polymer is from 5 to 30 mol % based on 100 mol % of the polymer, a content of the second structural unit in the polymer is from 30 to 70 mol % based on 100 mol % of the polymer, and a content of the third structural unit in the polymer is from 20 to 60 mol % based on 100 mol % of the polymer.
2. The photoresist composition according to claim 1 , wherein the second structural unit is a structural unit shown by formula (2-i), a structural unit shown by formula (2-ii), a structural unit shown by formula (2-iii), or a combination thereof,
wherein
each of R 4a and R 4b , and R 4c independently represents a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group,
each of R 5a , R 6a , and R 7a independently represents a linear or branched alkyl group having 1 to 5 carbon atoms, wherein a total number of carbon atoms of the alkyl groups represented by R 5a , R 6a , and R 7a is 7 or less,
each of R 5b and R 7b independently represents a linear or branched alkyl group having 1 to 3 carbon atoms,
m is an integer from 1 to 4,
R 5c represents a linear or branched alkyl group having 1 to 4 carbon atoms, and
n is an integer from 1 to 4.
3. The photoresist composition according to claim 1 , wherein the acid generator has an alicyclic structure having 8 to 30 carbon atoms.
4. The photoresist composition according to claim 1 , further comprising a water-repellent polymer additive that comprises a fluorine atom.
5. A resist pattern-forming method comprising:
applying the photoresist composition according to claim 1 on a substrate to form a resist film;
exposing the resist film; and
developing the exposed resist film.
6. The photoresist composition according to claim 1 , wherein R 3 is bonded to a carbon atom at a position 2 of the 5-oxo-4-oxatricyclo[4.3.1.1 3,8 ]undecane structure in the formula (1).
7. The photoresist composition according to claim 1 , wherein the content of the first structural unit in the polymer is from 5 to 20 mol % to 100 mol % of the polymer.
8. The photoresist composition according to claim 1 , wherein R 2 is a methanediyl group.
9. The photoresist composition according to claim 1 , wherein R 2 is a 1,1-ethanediyl group.
10. The photoresist composition according to claim 1 , wherein R 2 is a 1,4-cyclohexanediyl group.
11. The photoresist composition according to claim 1 , wherein the third structural unit comprises a lactone group.
12. The photoresist composition according to claim 1 , wherein the third structural unit comprises a norbornanelactone structure.
13. The photoresist composition according to claim 1 , wherein the third structural unit comprises a norbornanelactone group substituted with a methoxycarbonyl group.
14. The photoresist composition according to claim 6 , wherein the third structural unit comprises a lactone group.
15. The photoresist composition according to claim 6 , wherein the third structural unit comprises a norbornanelactone structure.
16. The photoresist composition according to claim 6 , wherein the third structural unit comprises a norbornanelactone group substituted with a methoxycarbonyl group.