Patterning process

Patent metadata

Field	Value
Publication number	US-9760010-B2
Application number	US-201615176967-A
Country	US
Kind code	B2
Filing date	Jun 8, 2016
Priority date	Jun 9, 2015
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

A pattern is formed by coating a resist composition comprising a fluorine-containing polymer, a base resin, an acid generator, and an organic solvent, baking the composition at 50-300° C. in an atmosphere of a solvent having a boiling point of 60-250° C., exposure, and development. In immersion lithography, the resist film is improved in water repellency and water slip, and LWR after pattern formation is reduced. In EB or EUV lithography, outgassing is suppressed and LWR is reduced.

First claim

The invention claimed is:

1. A pattern forming process comprising the steps of:
coating a resist composition comprising a fluorine-containing polymer, a base resin adapted to change its alkaline solubility under the action of acid, an acid generator, and an organic solvent,
baking the composition at a temperature of 50 to 300° C. in an atmosphere of a solvent having a boiling point of 60 to 250° C. under atmospheric pressure, to form a resist film,
exposing the resist film, and
developing the exposed resist film,
wherein the fluorine-containing polymer contains an α-trifluoromethylhydroxy or fluorosulfonamide group, and dissolves in an alkaline developer, said fluorine-containing polymer consisting of recurring units (a1) having the formula (1), recurring units (a2) having the formula (2), recurring units (a3) having a fluorinated alkyl or aryl group, recurring units (b1) to (b4) represented by the following formulae (3) to (6), and recurring units (c1) having a carboxyl or sulfo group:

wherein R 1 and R 4 are each independently hydrogen or methyl,
R 2 is a single bond, or a straight, or branched C 1 -C 12 alkylene group which may contain an ether, ester or carbonyl moiety,
R 3 is hydrogen, fluorine, methyl, trifluoromethyl or difluoromethyl, or R 3 may bond with R 2 to form a ring which may contain an ether moiety, fluorinated alkylene moiety or trifluoromethyl moiety,
R 5 is a single bond or a straight, branched or cyclic C 1 -C 12 alkylene group which may contain an ether, ester or carbonyl moiety,
R 6 is a fluorinated, straight, branched or cyclic C 1 -C 10 alkyl or phenyl group,
m is 1 or 2,
in case of m=1, X 1 is a single bond, —O—, —C(═O)—O—R 7 — or —C(═O)—NH—R 7 —, R 7 is a straight or branched C 1 -C 10 alkylene group which may contain an ester or ether moiety,
in case of m=2, X 1 is —C(═O)—O—R 8 ═ or —C(═O)—NH—R 8 ═, R 8 is an optionally ester or ether-containing, straight or branched C 1 -C 10 alkylene group, with one hydrogen atom eliminated,
X 2 is a single bond, phenylene group, —O—, —C(═O)—O—R 7 — or —C(═O)—NH—R 7 —,

wherein R 20 is hydrogen or methyl, Z 1 is a single bond, —C(═O)—O— or —O—, Z 2 and Z 3 are each independently phenylene or naphthylene, Z 4 is methylene, —O— or —S—, R 21 is a C 6 -C 20 aryl group or C 2 -C 20 alkenyl group, R 22 , R 23 , R 24 and R 25 are each independently hydrogen, hydroxyl, cyano, nitro, amino, halogen, straight, branched or cyclic C 1 -C 10 alkyl group, straight, branched or cyclic C 2 -C 6 alkenyl group, C 6 -C 10 aryl group, straight, branched or cyclic C 1 -C 10 alkoxy group, or straight, branched or cyclic C 2 -C 10 acyloxy group, and
wherein recurring units (a1) to (a3), recurring units (b1) to (b4), and recurring units (c1) are incorporated in the range of 0≦a1≦1.0, 0≦a2≦1.0, 0.5≦a1+a2≦1.0, 0≦a3<1.0, 0≦b1≦0.9, 0≦b2≦0.9, 0≦b3≦0.9, 0≦b4≦0.9, 0≦b1+b2+b3+b4≦0.9, 0≦c1≦0.6, and a1+a2+a3+b1+b2+b3+b4+c1=1.

2. The process of claim 1 wherein as a result of the baking step, the resist film is surface covered with the fluorine-containing polymer.

3. The process of claim 1 wherein the solvent having a boiling point of 60 to 250° C. under atmospheric pressure is selected from the group consisting of ester solvents of 4 to 10 carbon atoms, ketone solvents of 5 to 10 carbon atoms, ether solvents of 8 to 12 carbon atoms, aromatic solvents of 7 to 12 carbon atoms, and amide solvents of 4 to 8 carbon atoms.

4. The process of claim 3 wherein the ester solvents of 4 to 10 carbon atoms include propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, propylene glycol mono-t-butyl ether acetate, ethyl pyruvate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, t-butyl acetate, t-butyl propionate, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, and 2-phenylethyl acetate,
the ketone solvents of 5 to 10 carbon atoms include 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methyl cyclohexanone, acetophenone, methylacetophenone, cyclopentanone, cyclohexanone, cyclooctanone, and methyl-2-n-pentyl ketone,
the ether solvents of 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, di-s-butyl ether, di-n-pentyl ether, diisopentyl ether, di-s-pentyl ether, di-t-pentyl ether, di-n-hexyl ether, and anisole,
the aromatic solvents of 7 to 12 carbon atoms include toluene, xylene, ethylbenzene, isopropylbenzene, t-butylbenzene, and mesitylene, and
the amide solvents of 4 to 8 carbon atoms include N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylpropionamide, N-ethylpropionamide, and pivalamide.

5. The process of claim 1 wherein the exposure step is to expose the resist film to KrF excimer laser of wavelength 248 nm, ArF excimer laser of wavelength 193 nm, EUV of wavelength 3 to 15 nm, or EB.

6. The process of claim 5 wherein the exposure step is to expose the resist film to ArF excimer laser by immersion lithography.

7. The process of claim 1 wherein the base resin comprises recurring units having the formula (7) and/or recurring units having the formula (8):

wherein R 10 and R 12 are each independently hydrogen or methyl,
R 11 and R 14 are each independently hydrogen or an acid labile group,
Y 1 is a single bond, phenylene, naphthylene or —C(═O)—O—R 15 —, R 15 is a straight, branched or cyclic C 1 -C 10 alkylene group which may contain an ether moiety, ester moiety, lactone ring or hydroxyl moiety, a phenylene group or naphthylene group,
Y 2 is a single bond, phenylene, naphthylene, —C(═O)—O—R 16 —, —C(═O)—NH—R 16 —, —O—R 16 — or —S—R 16 —, R 16 is a straight, branched or cyclic C 1 -C 10 alkylene group which may contain an ether moiety, ester moiety, lactone ring or hydroxyl moiety,
R 13 is a single bond, a straight, branched or cyclic C 1 -C 16 divalent to pentavalent aliphatic hydrocarbon group which may contain an ether or ester moiety, or a phenylene group,
d1 and d2 are positive numbers satisfying 0≦d1<1.0, 0≦d2<1.0, and 0<d1+d2≦1.0, and n is an integer of 1 to 4.

8. The process of claim 1 wherein in the resist composition, 0.1 to 15 parts by weight of the fluorine-containing polymer is present per 100 parts by weight of the base resin.

9. The process of claim 1 wherein the recurring units (a1) having a fluorinated alkyl or aryl group are derived from monomers selected from the group consisting of the following formulae:

Assignees

• Shinetsu Chemical Co

Inventors

• Hatakeyama Jun
• Adachi Teppei

Classifications

• H10P50/692

  characterised by their composition, e.g. multilayer masks or materials · CPC title

• H10P76/2041

  Photolithographic processes · CPC title

• B05D3/0433

  the gas being a reactive gas · CPC title

• C08L33/16

  Homopolymers or copolymers of esters containing halogen atoms · CPC title

• C08F220/26

  Esters containing oxygen in addition to the carboxy oxygen · CPC title