Photoresist composition for deep ultraviolet lithography
The present invention relates to a photoresist composition comprising a photoacid generator and at least one polymer comprising at least one unit as described by structure 1, The invention also relates to a process for imaging the photoresist composition of the present invention, and to a process of making the polymer in the presence of an organic base.
1 . A process for making a fluoro polymer, where a fluoroalcohol polymer comprising an aliphatic cyclic fluoroalcohol unit is reacted with a compound capable of functionalizing the fluoroalcohol unit with an alkyloxycarbonylalkyl group, in the presence of a mixture comprising at least one organic base, and thereby forming the fluoro polymer comprising at least one unit as described by structure 1,
where, either
(i) R 1 is an aliphatic cyclic unit of a polymer, R 2 is selected from H, F, (C 1 -C 8 )alkyl, (C 1 -C 8 )fluoroalkyl, cycloalkyl, cyclofluoroalkyl, and (CR 3 R 4 )p(CO)OR 5 , and R f is selected from F, H, (C 1 -C 8 )alkyl, or a fully or partially fluorinated alkyl, and cyclofluoroalkyl, or
(ii) R 1 and R 2 combine to form an aliphatic cyclic unit of a polymer, and R f is selected from F, H, (C 1 -C 8 )alkyl and a fully or partially fluorinated alkyl, and cyclofluoroalkyl, or
(ii) R 1 and R f combine to form an aliphatic cyclic unit of a polymer, and R 2 is selected from H, F, (C 1 -C 8 )alkyl, (C 1 -C 8 )fluoroalkyl, cycloalkyl, cyclofluoroalkyl, and (CR 3 R 4 )p(CO)OR 5 ; and,
R 3 and R 4 are independently H, F, (C 1 -C 8 )alkyl, (C 1 -C 8 )fluoroalkyl, cycloalkyl, cyclofluoroalkyl, (CR 3 R 4 )p(CO)OR 5 , R 3 and R 4 may combine to form an alkylspirocyclic or a fluoroalkylspirocyclic group,
X is selected from (C 1 -C 8 )alkylene, (C 1 -C 8 )fluoroalkylene, O(C 1 -C 8 )alkylene, O(C 1 -C 8 )fluoroalkylene, cycloalkyl and fluorinatedcycloalkyl,
R 5 is H or an acid labile group, m=0-1, and p=1-4.
2 . The process of claim 1 , where the organic base is selected from an ammonium base, a phosphonium base and a sulfonium base.
3 . The process of claim 1 , where the organic base is (R 1 ′)(R 2 ′)(R 3 ′)(R 4 ′)NOH, and wherein R 1 ′,R 2 ′,R 3 ′ and R 4 ′ are independently (C 1 -C 20 ) alkyl.
4 . The process of claim 1 , where the mixture further comprises a salt selected from an ammonium salt, phosphonioum salt and sulfonium salt.
5 . The process of claim 1 , where the organic base is selected from tetramethyl ammonium hydroxide, tetrabutyl ammonium hydroxide and mixtures thereof.
6 . The process of claim 1 , where the mixture further comprises a solvent.
7 . The process of claim 1 , where reaction temperature can range from about −30° C. to about 80° C.
8 . The process of claim 1 , where the aliphatic cyclic unit is an aliphatic multicyclic unit or an aliphatic monocyclic unit.
9 . The process of claim 1 , where the alkyloxycarbonylalkyl group is selected from t-butyloxycarbonylmethyl, methyl-adamantyloxycarbonylmethyl, t-amyloxycarbonylmethyl, methyl-norbornyloxycarbonylmethyl, t-butyloxycarbonylpropyl and t-butyloxycarbonyldifluorobutyl.
10 . The process according to claim 1 , where the unit of structure 1 is selected from those derived from the following monomers,
where, in the above structures, R 1 -R 7 are independently H, F, (C1-C8)alkyl, (C1-C8)fluoroalkyl, and at least one of R 1 -R 6 forms the unit described in structure 1.
11 . The process according to claim 1 , where the unit of structure 1 is selected from the group derived from the following monomers,
12 . The process of claim 1 , where the aliphatic cyclic unit is a monocyclic unit.
13 . The process of claim 1 , where the fluoroalcohol polymer is selected from,
14 . The process of claim 1 , where the fluoroalcohol polymer is selected from poly(bicyclo[2.2.1]hept-5-en-2-yl)-1,1,1-trifluoro-2-(trifluoromethyl)propan-2-ol), poly(1,1,2,3,3-pentafluoro-4-trifluoromethyl-4-hydroxy-1,6-heptadiene and poly(1,1,2,3,3-pentafluoro-4-trifluoroalkyl-4-hydroxy-1,6-heptadiene).
15 . The process of claim 1 , where the fluoroalcohol polymer comprises a mixture of polymers comprising monocyclic units and polymers comprising multicyclic units.
16 . The process of claim 15 , where the polymer mixture is poly(bicyclo[2.2.1]hept-5-en-2-yl)-1,1,1-trifluoro-2-(trifluoromethyl)propan-2-ol) with poly(1,1,2,3,3-pentafluoro-4-trifluoromethyl-4-hydroxy-1,6-heptadiene).
17 . The process of claim 1 , where the acid labile group is selected from secondary and tertiary alkyls, acetals and ketals, trimethylsilyl, β-trimethylsilyl substituted alkyls, tetrahydrofuranyl, tetrahydropyranyl, substituted or unsubstituted methoxymethoxycarbonyl, and β-trialkylsilylalkyl.
18 . The process of claim 1 , where the fluoro polymer further comprises units containing nonacid labile groups and/or acid labile groups.
19 . A composition comprising the fluoro polymer of claim 1 and a photoacid generator.
20 . A composition comprising the fluoro polymer of claim 12 and a photoacid generator.