Resist composition and patterning process
The resist composition includes a base polymer and a salt. The salt consisting of an anion derived from an iodized or brominated phenol and a cation derived from a 2,5,8,9-tetraaza-1-phosphabicyclo[3.3.3]undecane, biguanide or phosphazene compound. The resist composition exerts a high sensitizing effect and an acid diffusion suppressing effect, causes no film thickness loss after development, and is improved in resolution, LWR and CDU when a pattern is formed therefrom by lithography.
1. A resist composition comprising a base polymer and a salt, the salt consisting of an anion derived from an iodized phenol compound and a cation derived from a 2,5,8,9-tetraaza-1-phosphabicyclo[3.3.3]undecane, biguanide or phosphazene compound, the salt having formula (A):
wherein m is 2 or 3, and n is an integer of 0 to 2, 2≤m+n≤5,
X BI is iodine,
R 1 is hydroxyl, an optionally fluorinated or chlorinated C 1 -C 6 saturated hydrocarbyl group, an optionally fluorinated or chlorinated C 1 -C 6 saturated hydrocarbyloxy group, an optionally fluorinated or chlorinated C 2 -C 6 saturated hydrocarbyloxycarbonyl group, formyl, an optionally fluorinated or chlorinated C 2 -C 6 saturated hydrocarbylcarbonyl group, an optionally fluorinated or chlorinated C 2 -C 6 saturated hydrocarbylcarbonyloxy group, an optionally fluorinated or chlorinated C 1 -C 4 saturated hydrocarbylsulfonyloxy group, a C 6 -C 10 aryl group, fluorine, chlorine, amino, nitro, cyano, —NR 1A —C(═O)—R 1B , or —NR 1A —C(═O)—O—R 1B , R 1A is hydrogen or a C 1 -C 6 saturated hydrocarbyl group, R 1B is a C 1 -C 6 saturated hydrocarbyl group or a C 2 -C 8 unsaturated aliphatic hydrocarbyl group,
A + is a cation having the formula (A)-1, (A)-2 or (A)-3:
wherein R 11 to R 13 are each independently a C 1 -C 24 hydrocarbyl group which may contain a heteroatom,
R 14 to R 21 are each independently hydrogen or a C 1 -C 24 hydrocarbyl group which may contain a heteroatom, a pair of R 14 and R 15 , R 15 and R 16 , R 16 and R 17 , R 17 and R 18 , R 18 and R 19 , R 19 and R 20 , or R 20 and R 21 may bond together to form a ring with the nitrogen atom to which they are attached, or the nitrogen atoms to which they are attached and intervening carbon atom, the ring optionally containing an ether bond,
R 22 to R 29 are each independently hydrogen or a C 1 -C 24 hydrocarbyl group which may contain a heteroatom, a pair of R 22 and R 23 , R 23 and R 24 , R 24 and R 25 , R 25 and R 26 , R 26 and R 27 , or R 27 and R 28 may bond together to form a ring with the nitrogen atom to which they are attached, or the nitrogen atoms to which they are attached and intervening phosphorus atom, a pair of R 22 and R 23 , R 24 and R 25 , R 26 and R 27 , or R 28 and R 29 may bond together to form a group having the formula (A)-3-1, and R 23 may be a group having the formula (A)-3-2 when R 22 is hydrogen,
wherein R 30 to R 39 are each independently hydrogen or a C 1 -C 24 hydrocarbyl group which may contain a heteroatom, a pair of R 30 and R 31 , R 31 and R 32 , R 32 and R 33 , R 33 and R 34 , R 34 and R 35 , R 36 and R 37 , or R 38 and R 39 may bond together to form a ring with the nitrogen atom to which they are attached, or the nitrogen atoms to which they are attached and intervening phosphorus atom, a pair of R 30 and R 31 , R 32 and R 33 , or R 34 and R 35 may bond together to form a group having the formula (A)-3-1,
the broken line designates a valence bond.
2. The resist composition of claim 1 , further comprising an acid generator capable of generating a sulfonic acid, sulfonimide or sulfonmethide.
3. 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 A is each independently hydrogen or methyl, R 41 and R 42 each are an acid labile group, Y 1 is a single bond, phenylene group, naphthylene group, or C 1 -C 12 linking group containing at least one moiety selected from ester bond and lactone ring, and Y 2 is a single bond or ester bond.
4. The resist composition of claim 3 which is a chemically amplified positive resist composition.
5. The resist composition of claim 1 wherein the base polymer is free of an acid labile group.
6. The resist composition of claim 5 which is a chemically amplified negative resist composition.
7. The resist composition of claim 1 wherein the base polymer comprises recurring units of at least one type selected from recurring units having the formulae (f1) to (f3):
wherein R A is each independently hydrogen or methyl,
Z 1 is a single bond, phenylene group, —O—Z 11 —, —C(═O)—O—Z 11 — or —C(—O)—NH—Z 11 —, Z 11 is a C 1 -C 6 aliphatic hydrocarbylene group or phenylene group, which may contain a carbonyl, ester bond, ether bond or hydroxyl moiety,
Z 2 is a single bond, —Z 21 —C(═O)—O—, —Z 21 —O— or —Z 21 —O—C(═O)—, Z 21 is a C 1 -C 12 saturated hydrocarbylene group which may contain a carbonyl moiety, ester bond or ether bond,
Z 3 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, —O—Z 31 , —C(═O)—O—Z 31 —, or —C(—O)—NH—Z 31 —, Z 31 is a C 1 -C 6 aliphatic hydrocarbylene group, phenylene group, fluorinated phenylene group, or trifluoromethyl-substituted phenylene group, which may contain a carbonyl moiety, ester bond, ether bond or hydroxyl moiety,
R 51 to R 58 are each independently a C 1 -C 20 hydrocarbyl group which may contain a heteroatom, any two of R 53 , R 54 and R 55 or any two of R 56 , R 57 and R 58 may bond together to form a ring with the sulfur atom to which they are attached,
R HF is hydrogen or trifluoromethyl, and
M is a non-nucleophilic counter ion.
8. The resist composition of claim 1 , further comprising an organic solvent.
9. The resist composition of claim 1 , further comprising a surfactant.
10. A process for forming a pattern comprising the steps of applying the resist composition of claim 1 to form a resist film on a substrate, exposing the resist film to high-energy radiation, and developing the exposed resist film in a developer.
11. The process of claim 10 wherein the high-energy radiation is ArF excimer laser radiation of wavelength 193 nm or KrF excimer laser radiation of wavelength 248 nm.
12. The process of claim 10 wherein the high-energy radiation is EB or EUV of wavelength 3 to 15 nm.
13. The resist composition of claim 1 wherein A + is a cation having the formula (A)-1 or (A)-2.