Resist composition and patterning process
A resist composition comprising a base polymer and a phosphazene salt compound offers a high dissolution contrast, minimal LWR, and dimensional stability on PPD.
1. A resist composition comprising a base polymer and a phosphazene salt compound having the formula (A):
wherein R 1 to R 7 are each independently hydrogen, or a C 1 -C 24 straight, branched or cyclic alkyl group, C 2 -C 24 straight, branched or cyclic alkenyl group, C 2 -C 24 straight, branched or cyclic alkynyl group, or C 6 -C 20 aryl group, which may contain an ester, ether, sulfide, sulfoxide, carbonate, carbamate, sulfone, halogen, amino, amide, hydroxy, thiol or nitro moiety, a pair of R 1 and R 2 , R 2 and R 3 , R 3 and R 4 , R 4 and R 5 , R 5 and R 6 , or R 6 and R 7 may bond together to form a ring, or a pair of R 2 and R 3 , R 4 and R 5 , or R 6 and R 7 , taken together, may form a double bond or a group having the formula (A)-1, R 1 may be a group having the formula (A)-2,
wherein R 8 to R 17 are each independently hydrogen, or a C 1 -C 24 straight, branched or cyclic alkyl group, C 2 -C 24 straight, branched or cyclic alkenyl group, C 2 -C 24 straight, branched or cyclic alkynyl group, or C 6 -C 20 aryl group, a pair of R 8 and R 9 , R 9 and R 10 , R 10 and R 11 , R 11 and R 12 , R 12 and R 13 , R 14 and R 15 , or R 16 and R 17 may bond together to form a ring, or a pair of R 8 and R 9 , R 10 and R 11 , or R 12 and R 13 , taken together, may form a double bond or a group having the formula (A)-1,
A − is an anion selected from the group consisting of hydroxide, chloride, bromide, iodide, nitrate, nitrite, chlorate, chlorite, perchlorate, hydrogencarbonate, dihydrogenphosphate, hydrogensulfate, thiocyanate, hydrogenoxalate, cyanide, iodate ions, and anions of the formulae (M-1) and (M-2):
wherein R 18 is hydrogen, or a C 1 -C 30 straight, branched or cyclic alkyl group, C 2 -C 30 straight, branched or cyclic alkenyl group, C 2 -C 30 straight, branched or cyclic alkynyl group, C 6 -C 20 aryl group, C 7 -C 20 aralkyl group, or C 3 -C 20 aromatic or aliphatic heterocycle-containing group, which may contain an ester, ether, sulfide, sulfoxide, carbonate, carbamate, sulfone, halogen, amino, amide, hydroxy, thiol or nitro moiety, with the proviso that R 18 does not contain a group of the formula (A)-3:
wherein Ar is a C 6 -C 16 aromatic group, R 21 and R 22 are each independently hydrogen, hydroxy, alkoxy, C 1 -C 6 straight, branched or cyclic alkyl group, or C 6 -C 10 aryl group, R 19 is fluorine, or a C 1 -C 10 straight, branched or cyclic fluoroalkyl group or fluorophenyl group, which may contain a hydroxy, ether, ester or alkoxy moiety, R 20 is hydrogen, or a C 1 -C 10 straight, branched or cyclic alkyl group, C 2 -C 10 straight, branched or cyclic alkenyl group, C 2 -C 10 straight or branched alkynyl group, or C 6 -C 10 aryl group, which may contain a hydroxy, ether, ester or alkoxy moiety,
wherein the carboxylate anion having formula (M-1) is selected from the group consisting of the following formulae:
2. The resist composition of claim 1 , further comprising an acid generator capable of generating sulfonic acid, sulfonimide or sulfonmethide.
3. The resist composition of claim 1 , further comprising an organic solvent.
4. The resist composition of claim 1 wherein the base polymer comprises recurring units having the formula (a1) or recurring units having the formula (a2):
wherein R 31 and R 33 are each independently hydrogen or methyl, R 32 and R 34 are each independently an acid labile group, X is a single bond, ester group, phenylene group, naphthylene group or a C 1 -C 12 linking group containing lactone ring, and Y is a single bond or ester group.
5. The resist composition of claim 4 , further comprising a dissolution inhibitor.
6. The resist composition of claim 4 which is a chemically amplified positive resist composition.
7. The resist composition of claim 1 wherein the base polymer is free of an acid labile group.
8. The resist composition of claim 7 , further comprising a crosslinker.
9. The resist composition of claim 7 which is a chemically amplified negative resist composition.
10. The resist composition of claim 1 wherein the base polymer comprises recurring units of at least one type selected from the formulae (f1) to (f3):
wherein R 51 , R 55 and R 59 each are hydrogen or methyl,
R 52 is a single bond, phenylene, —O—R 63 —, or —C(═O)—Y 1 —R 63 —, Y 1 is —O— or —NH—, R 63 is a C 1 -C 6 straight, branched or cyclic alkylene or alkenylene group which may contain a carbonyl, ester, ether or hydroxyl moiety, or phenylene group,
R 53 , R 54 , R 56 , R 57 , R 58 , R 60 , R 61 , and R 62 are each independently a C 1 -C 12 straight, branched or cyclic alkyl group which may contain a carbonyl, ester or ether moiety, or a C 6 -C 12 aryl group, C 7 -C 20 aralkyl group or mercaptophenyl group,
A 1 is a single bond, -A 0 -C(═O)—O—, -A 0 -O— or -A 0 -O—C(═O)—, A 0 is a C 1 -C 12 straight, branched or cyclic alkylene group which may contain a carbonyl, ester or ether moiety,
A 2 is hydrogen or trifluoromethyl,
Z 1 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, —O—R 64 —, or —C(═O)—Z 2 —R 64 —, Z 2 is —O— or —NH—, R 64 is a C 1 -C 6 straight, branched or cyclic alkylene or alkenylene group which may contain a carbonyl, ester, ether or hydroxyl moiety, or phenylene, fluorinated phenylene or trifluoromethyl-substituted phenylene group,
M − is a non-nucleophilic counter ion, and f1, f2 and f3 are numbers in the range: 0≤f1≤0.5, 0≤f2≤0.5, 0≤f3≤0.5, and 0<f1+f2+f3≤0.5.
11. The resist composition of claim 1 , further comprising a surfactant.
12. A process for forming a pattern comprising the steps of applying the resist composition of claim 1 onto a substrate, baking to form a resist film, exposing the resist film to high-energy radiation, and developing the exposed film in a developer.
13. The process of claim 12 wherein the high-energy radiation is ArF excimer laser radiation of wavelength 193 nm or KrF excimer laser radiation of wavelength 248 nm.
14. The process of claim 12 wherein the high-energy radiation is electron beam or extreme ultraviolet radiation of wavelength 3 to 15 nm.
15. A resist composition comprising a base polymer and a phosphazene salt compound having the formula (A):
wherein R 1 to R 7 are each independently hydrogen, or a C 1 -C 24 straight, branched or cyclic alkyl group, C 2 -C 24 straight, branched or cyclic alkenyl group, C 2 -C 24 straight, branched or cyclic alkynyl group, or C 6 -C 20 aryl group, which may contain an ester, ether, sulfide, sulfoxide, carbonate, carbamate, sulfone, halogen, amino, amide, hydroxy, thiol or nitro moiety, a pair of R 1 and R 2 , R 2 and R 3 , R 3 and R 4 , R 4 and R 5 , R 5 and R 6 , or R 6 and R 7 may bond together to form a ring, or a pair of R 2 and R 3 , R 4 and R 5 , or R 6 and R 7 , taken together, may form a double bond or a group having the formula (A)-1, R 1 may be a group having the formula (A)-2,
wherein R 8 to R 17 are each independently hydrogen, or a C 1 -C 24 straight, branched or cyclic alkyl group, C 2 -C 24 straight, branched or cyclic alkenyl group, C 2 -C 24 straight, branched or cyclic alkynyl group, or C 6 -C 20 aryl group, a pair of R 8 and R 9 , R 9 and R 10 , R 10 and R 11 , R 11 and R 12 , R 12 and R 13 , R 14 and R 15 , or R 16 and R 17 may bond together to form a ring, or a pair of R 8 and R 9 , R 10 and R 11 , or R 12 and R 13 , taken together, may form a double bond or a group having the formula (A)-1,
A − is an anion selected from the group consisting of hydroxide, chloride, bromide, iodide, nitrate, nitrite, chlorate, chlorite, perchlorate, hydrogencarbonate, dihydrogenphosphate, hydrogensulfate, thiocyanate, hydrogenoxalate, cyanide, iodate ions, and anions of the formulae (M-1) and (M-2):
wherein R 18 is hydrogen, or a C 1 -C 30 straight, branched or cyclic alkyl group, C 2 -C 30 straight, branched or cyclic alkenyl group, C 2 -C 30 straight, branched or cyclic alkynyl group, C 6 -C 20 aryl group, or C 7 -C 20 aralkyl group, which may contain an ester, ether, sulfide, sulfoxide, carbonate, carbamate, sulfone, halogen, amino, amide, hydroxy, thiol or nitro moiety, with the proviso that R 18 does not contain a group of the formula (A)-3:
wherein Ar is a C 6 -C 16 aromatic group, R 21 and R 22 are each independently hydrogen, hydroxy, alkoxy, C 1 -C 6 straight, branched or cyclic alkyl group, or C 6 -C 10 aryl group, R 19 is fluorine, or a C 1 -C 10 straight, branched or cyclic fluoroalkyl group or fluorophenyl group, which may contain a hydroxy, ether, ester or alkoxy moiety, R 20 is hydrogen, or a C 1 -C 10 straight, branched or cyclic alkyl group, C 2 -C 10 straight, branched or cyclic alkenyl group, C 2 -C 10 straight or branched alkynyl group, or C 6 -C 10 aryl group, which may contain a hydroxy, ether, ester or alkoxy moiety.
16. The resist composition of claim 15 wherein the base polymer comprises recurring units having the formula (a1) or recurring units having the formula (a2):
wherein R 31 and R 33 are each independently hydrogen or methyl, R 32 and R 34 are each independently an acid labile group, X is a single bond, ester group, phenylene group, naphthylene group or a C 1 -C 12 linking group containing lactone ring, and Y is a single bond or ester group.
17. The resist composition of claim 16 which is a chemically amplified positive resist composition.
18. The resist composition of claim 15 wherein the base polymer is free of an acid labile group.
19. The resist composition of claim 18 which is a chemically amplified negative resist composition.
20. A process for forming a pattern comprising the steps of applying the resist composition of claim 15 onto a substrate, baking to form a resist film, exposing the resist film to high-energy radiation, and developing the exposed film in a developer.