RESIST PROTECTIVE COATING COMPOSITION AND PATTERNING PROCESS

• US 20090286182A1
• Filed: 05/11/2009
• Published: 11/19/2009
• Est. Priority Date: 05/12/2008
• Status: Active Grant

• Current Assignee: Shin-Etsu Chemical Company Limited
• Original Assignee: Shin-Etsu Chemical Company Limited
• Inventors: HARADA, Yuji, HASEGAWA, Koji, HATAKEYAMA, Jun, SHINACHI, Satoshi
• Granted Patent: US 8,158,330 B2
• Time in Patent Office: Days
• US Class Current: 430/285.100
• CPC Class Codes: C08F 220/24 containing perhaloalkyl radicals
• CPC Class Codes: C08F 232/08 having condensed rings coumarone-indene polymers C08F244/00
• CPC Class Codes: G03F 7/0046 with perfluoro compounds, e.g. for dry lithography G03F7/0048 takes precedence
• CPC Class Codes: G03F 7/11 having cover layers or intermediate layers, e.g. subbing layers G03F7/091 - G03F7/093, B41N3/03 take precedence
• CPC Class Codes: G03F 7/2041 in the presence of a fluid, e.g. immersion; using fluid cooling means
• CPC Class Codes: Y10S 430/106 Binder containing
• CPC Class Codes: Y10S 430/108 Polyolefin or halogen containing
• CPC Class Codes: Y10S 430/111 Polymer of unsaturated acid or ester

Abstract

A protective coating composition comprising a copolymer of an alkali-soluble (α-trifluoromethyl)acrylate and a norbornene derivative as a base polymer, optionally in admixture with a second polymer containing sulfonic acid and/or sulfonic acid amine salt in repeat units is applied onto a resist film. The protective coating is effective in minimizing development defects and forming a resist pattern of improved profile.

Claims

1. A resist protective coating composition comprising a polymer P1 comprising repeat units of the general formulae (1a) and (2a):

wherein R^1a and R^1b are hydrogen or straight, branched or cyclic C₁-C₁₀ alkyl, R^1a and R^1b may bond together to form a non-aromatic ring with the carbon atom to which they are attached, R² is hydrogen, methyl or trifluoromethyl, R³ is hydrogen or an acid labile group, and a1 and b1 are numbers satisfying 0<

a1<

1, 0<

b1<

1, and 0<

a1+b1≦

1.

5. The resist protective coating composition of claim 1, further comprising a polymer P3 comprising repeat units of the general formulae (3a), (3b), (4a) and (4b):

wherein

R^5a and R^5b are hydrogen or methyl,

R⁶ is a single bond, C₁-C₄ alkylene, —

C(═

O)—

O—

or —

C(═

O)—

NH—

,

R⁷ is a single bond or straight, branched or cyclic C₁-C₈ alkylene,

R^8a to R^8d and R^10a to R^10c are each independently selected from the group consisting of hydrogen, straight, branched or cyclic C₁-C₁₂ alkyl, alkenyl, oxoalkyl and oxoalkenyl, C₆-C₂₀ aryl, C₇-C₁₂ aralkyl and aryloxoalkyl, in which some or all hydrogen atoms may be substituted by alkoxy groups, R^8a to R^8d and R^10a to R^10c may contain a nitrogen atom, ether, ester, hydroxyl or carboxyl group, at least two of R^8a to R^8d and at least two of R^10a to R^10c may bond together to form a ring with the nitrogen atom to which they are attached, in this event, each participant in the ring formation independently denotes a C₃-C₁₀ alkylene or a group forming with the nitrogen atom a hetero-aromatic ring containing said nitrogen atom therein,

R⁹ is straight, branched or cyclic C₁-C₈ alkylene,

R¹¹ is a straight, branched or cyclic C₁-C₂₀ alkyl which may have a carbonyl, ester, ether group or halogen atom, or a C₆-C₁₀ aryl which may have a carbonyl, ester, ether, halogen atom, C₁-C₁₀ alkyl or fluoroalkyl,

c1, c2, d1, and d2 are numbers satisfying 0≦

c1<

1, 0≦

c2<

1, 0≦

d1<

1, 0≦

d2<

1, and 0<

c1+c2+d1+d2<

1, and if 0<

d2, then 0<

c2.

6. The resist protective coating composition of claim 1, further comprising a polymer P3′

comprising repeat units of the general formulae (3a), (3b), (4a), (4b) and (5);

wherein

R^5a to R^5c are hydrogen or methyl,

R⁶ is a single bond, C₁-C₄ alkylene, —

C(═

O)—

O—

or —

C(═

O)—

NH—

,

R⁷ is a single bond or straight, branched or cyclic C₁-C₈ alkylene,

R^8a to R^8d and R^10a to R^10c are each independently selected from the group consisting of hydrogen, straight, branched or cyclic C₁-C₁₂ alkyl, alkenyl, oxoalkyl and oxoalkenyl, C₆-C₂₀ aryl, C₇-C₁₂ aralkyl and aryloxoalkyl, in which some or all hydrogen atoms may be substituted by alkoxy groups, R⁸² to R^8d and R^10a to R^10c may contain a nitrogen atom, ether, ester, hydroxyl or carboxyl group, at least two of R^8a to R^8d and at least two of R^10a to R^10c may bond together to form a ring with the nitrogen atom to which they are attached, in this event, each participant in the ring formation independently denotes a C₃-C₁₀ alkylene or a group forming with the nitrogen atom a hetero-aromatic ring containing said nitrogen atom therein,

R⁹ is straight, branched or cyclic C₁-C₈ alkylene,

R¹¹ is a straight, branched or cyclic C₁-C₂₀ alkyl which may have a carbonyl, ester, ether group or halogen atom, or a C₆-C₁₀ aryl which may have a carbonyl, ester, ether, halogen atom, C₁-C₁₀ alkyl or fluoroalkyl,

R^12a and R^12b are hydrogen or straight, branched or cyclic C₁-C₁₀ alkyl, R^12a and R^12b may bond together to form a ring with the carbon atom to which they are attached,

c1, c2, d1, d2, and e are numbers satisfying 0≦

c1<

1, 0≦

c2<

1, 0≦

d1<

1, 0≦

d2<

1, 0<

e<

1, 0<

c1+c2+d1+d2<

1, and 0.3≦

c1+c2+d1+d2+e≦

1, and if 0<

d2, then 0<

c2.

7. The protective coating composition of claim 1, further comprising a solvent.

8. The protective coating composition of claim 7 wherein the solvent comprises an ether compound of 8 to 12 carbon atoms.

9. The protective coating composition of claim 8 wherein the solvent comprises at least one ether compound of 8 to 12 carbon atoms selected from the group consisting of di-n-butyl ether, diisobutyl ether, di-sec-butyl ether, di-n-pentyl ether, diisopentyl ether, di-sec-pentyl ether, di-t-amyl ether, di-n-hexyl ether, methyl cyclopentyl ether, and methyl cyclohexyl ether.

10. The protective coating composition of claim 8 wherein the solvent comprises a mixture of the ether compound and 0.1 to 90% by weight of a higher alcohol of 4 to 10 carbon atoms.

11. The higher protective coating composition of claim 10 wherein the alcohol is at least one compound selected from the group consisting of 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-amyl alcohol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2,2-diethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, and cyclohexanol.

12. A pattern forming process comprising the steps of (1) applying a resist material onto a substrate to form a photoresist film, (2) applying the resist protective coating composition of claim 1 onto the photoresist film to form a protective coating thereon, (3) heat treating and exposing the coated substrate to high-energy radiation from a projection lens through a photomask while holding a liquid between the substrate and the projection lens, and (4) developing with a developer.

13. The process of claim 12 wherein the liquid is water.

14. The process of claim 12 wherein the high-energy radiation has a wavelength in the range of 180 to 250 nm.

15. The process of claim 12 wherein the developing step uses a liquid alkaline developer for thereby developing the photoresist film to form a resist pattern and stripping the resist protective coating therefrom at the same time.

16. A lithography process for forming a pattern, comprising the steps of forming a protective coating on a photoresist layer disposed on a mask blank, exposing the layer structure in vacuum to electron beam, and developing,

the protective coating being formed of the protective coating composition of claim 1.

2. A resist protective coating composition comprising a polymer P1′

comprising repeat units of the general formulae (1a), (1b) and (2a);

wherein R^1a and R^1b are hydrogen or straight, branched or cyclic C₁-C₁₀ alkyl, R^1a and R^1b may bond together to form a non-aromatic ring with the carbon atom to which they are attached, R² is hydrogen, methyl or trifluoromethyl, R³ is hydrogen or an acid labile group, R^4a to R^4c are hydrogen or straight, branched or cyclic C₁-C₁₀ alkyl, and a1, a2 and b1 are numbers satisfying 0<

a1<

1, 0<

a2<

1, 0<

b1<

1, and 0<

a1+a2+b1≦

1.

3. A resist protective coating composition comprising a polymer P1″

comprising repeat units of the general formulae (1a), (1b), (2a) and (2b);

wherein R^1a and R^1b are hydrogen or straight, branched or cyclic C₁-C₁₀ alkyl, R^1a and R^1b may bond together to form a non-aromatic ring with the carbon atom to which they are attached, R² is hydrogen, methyl or trifluoromethyl, R³ is hydrogen or an acid labile group, R^4a to R^4c are hydrogen or straight, branched or cyclic C₁-C₁₀ alkyl, R⁵ is straight, branched or cyclic C₁-C₁₀ alkyl, and a1, a2, b1 and b2 are numbers satisfying 0<

a1<

1, 0≦

a2<

1, 0≦

b1<

1, 0<

b2 <

1, and 0<

a1+a2+b1+b2≦

1.

4. A resist protective coating composition comprising a polymer P2 corresponding to a polymer P1-H comprising repeat units of the general formulae (1a) and (2a′

) wherein some or all of hydroxyl groups in either one or both of formula (1a) and formula (2a′

) are protected with protective groups,

wherein R^1a and R^1b are hydrogen or straight, branched or cyclic C₁-C₁₀ alkyl, R^1a and R^1b may bond together to form a non-aromatic ring with the carbon atom to which they are attached, R² is hydrogen, methyl or trifluoromethyl, and a1 and b1 are numbers satisfying 0<

a1<

1, 0<

b1<

1, and 0<

a1+b1≦

1.