KR20170077815A - Resist composition and patterning process - Google Patents

Abstract

(식 중, R¹∼R⁸은 각각 독립적으로 수소 원자 또는 소정의 치환기이다. A^-는 수산화물 이온, 염소 이온, 브롬 이온, 요오드 이온, 질산 이온, 아질산 이온, 염소산 이온, 아염소산 이온, 과염소산 이온, 탄산수소 이온, 인산이수소 이온, 황산수소 이온, 티오시안산 이온, 옥살산수소 이온, 시안화물 이온, 또는 하기 식 (M-1) 혹은 (M-2)로 표시되는 음이온이다.

)[PROBLEMS] Provided are a resist material which has a high dissolution contrast and a small LWR even in a positive resist material, and which does not cause dimensional change in PPD, and a pattern forming method using the resist material.
[MEANS FOR SOLVING PROBLEMS] A resist material comprising a base polymer and an asymmetric salt compound represented by the following formula (A).

Wherein R ¹ to R ⁸ are each independently a hydrogen atom or a predetermined substituent group, and A ^- represents a hydrogen atom, a chloride ion, a bromide ion, an iodide ion, a nitrate ion, a nitrite ion, a chlorate ion, (M-1) or (M-2), wherein the anion is at least one selected from the group consisting of hydrogen ions, hydrogen carbonate ions, hydrogen phosphate ions, hydrogen sulfate ions, thiocyanate ions, hydrogen oxalate ions and cyanide ions.

)

Description

RESIST MATERIAL AND METHOD FOR FORMING RESIST COMPOSITION AND PATTERNING PROCESS

The present invention relates to a resist material containing an asymmetric salt compound and a pattern forming method using the same.

With the increasingly high integration and high speed of LSI, the miniaturization of pattern rules is progressing rapidly. In particular, the flash memory market is expanding and memory capacity is increasing. As a state-of-the-art micromachining technology, devices with 65 nm nodes by ArF lithography are mass-producing, and preparations for mass production of 45 nm nodes by next-generation ArF immersion lithography are underway. As the next-generation 32 nm node, liquid immersion lithography using ultra-high NA lens combined with liquid having a refractive index higher than that of water and high refractive index lens and high refractive index resist material, extreme ultraviolet (EUV) lithography with a wavelength of 13.5 nm, double exposure Patterning lithography) and the like are under review as candidates.

A chemically amplified positive resist material which generates an acid by irradiation of light or electron beam (EB) to cause a deprotection reaction and a chemically amplified negative resist material which causes a crosslinking reaction with an acid, The addition effect of the quencher for the purpose of controlling the diffusion to the unexposed portion of the light to improve the contrast was very effective. For this reason, many amine cements have been proposed (Patent Documents 1 to 3).

And the contrast of the light decreases as the micronization proceeds and approaches the diffraction limit of the light. Due to the lowering of the contrast of light, in the positive type resist film, resolution of the hole pattern or trench pattern and lowering of the focus margin occur.

Attempts have been made to improve the dissolution contrast of the resist film in order to prevent the degradation of the resolution of the resist pattern due to the lowering of the contrast of light. Along with this, attempts have been made to suppress acid diffusion which causes the image in the resist pattern to be blurred.

A chemically amplified resist material using an acid propagation mechanism in which an acid is generated by an acid has been proposed. The concentration of acid increases linearly with an increase in the normal exposure dose, but in the case of acid growth, the concentration of the acid rapidly increases non-linearly with the increase in the exposure dose. Although the acid proliferation system has the merit of further enhancing the advantages such as high contrast and high sensitivity of the chemically amplified resist film, the environmental resistance due to amine contamination is deteriorated and the chemical amplification resist film such as the degradation of the marginal resolution due to the increase of the acid diffusion distance It is a mechanism that is very difficult to control when it is desired to use it for practical use because it further deteriorates the defect.

Another method for increasing the contrast is to lower the concentration of the amine with an increase in the exposure amount. To this, the application of a compound which loses its function as a quencher by light can be considered.

The acid labile groups used in the (meth) acrylate polymers for ArF use a photoacid generator in which a sulfonic acid in which the? -Position is substituted with fluorine is used, whereby the deprotection reaction proceeds, but the? The acid generator generating sulfonic acid or carboxylic acid does not undergo a deprotection reaction. when a sulfonium salt or iodonium salt generating a sulfonic acid in which the? -position is not substituted with fluorine is mixed with a sulfonium salt or iodonium salt in which the? -position in which the? -position is substituted with fluorine is substituted with fluorine A sulfonium salt or an iodonium salt which generates a non-sulfonic acid causes ion exchange with a sulfonic acid substituted at the? -Position with fluorine. The sulfonic acid in which the alpha -position generated by the light is substituted with fluorine is returned to the sulfonium salt or the iodonium salt by ion exchange. Therefore, the sulfonium salt or iodonium salt of the carboxylic acid, Acts as a keeper.

The sulfonium salt or iodonium salt generating a sulfonic acid in which the? -Position is not substituted with fluorine also functions as a photo-decomposable quencher since it loses its ability as a kenapatite due to photodegradation. Although the structural formula is not disclosed, it has been disclosed that the margin of the trench pattern is enlarged by the addition of the photolytic cracker (Non-Patent Document 3). However, the influence on the performance improvement is small, and development of a retainer for improving the contrast is demanded.

Patent Document 4 proposes an onium salt-type kencer in which a carboxylic acid having an amino group is generated by light, and a lactam is generated by an acid to lower the basicity. The diffusion of acid is controlled by the basicity of the unexposed portion where the amount of acid generated is lowered by the mechanism in which the basicity is lowered by the acid, and when the amount of acid generated is large, the basicity of the quencher is lowered, . As a result, the difference in the amount of acid (acid amount) between the exposed portion and the unexposed portion can be increased, and the contrast is improved. However, this method also has a drawback that acid diffusion is increased.

Bicine and phosphazenes are known as super-strong base compounds. They have a higher basicity than diazabicyclo-undecene (DBU), and use thereof as a curing reaction catalyst for epoxy has been studied. For example, Patent Documents 5 and 6 disclose that a base generator that generates guanidine, bigninoide, phosphazene, 2,5,8,9-tetraaza-1-phosphabicyclo [3.3.3] undecane by light, Has been proposed. Generally, the amount of acid generated from the photoacid generator increases with an increase in the exposure dose. However, when the photoacid generator and the photoacid generator are used in combination, the amount of the photoacid generator and the amount of the base generator are the same, , The amount of acid is not increased even if the exposure amount is increased. When the generation efficiency is high due to a large amount of the photoacid generator, the amount of acid increases with an increase in exposure dose, but the amount of increase is small and the contrast of the resist is also low.

A method of forming a negative tone by the development of an organic solvent has attracted attention. When a hole pattern is to be formed by photoexposure, a hole pattern having the smallest pitch can be formed when a combination of a mask of bright pattern and a negative resist is formed. Here, it is a problem that the dimension of the pattern after development changes due to post-exposure bake (PEB) after exposure and post-PEB delay (PPD) between development. It is considered that the acid is gradually diffused to the unexposed portion during the room temperature after PEB, and the deprotection reaction proceeds. In order to solve the PPD problem, one method is to carry out high-temperature PEB using a protecting agent having a high activation energy. Since the PPD is a reaction at room temperature, the larger the temperature gap with the PEB, the less the influence of the PPD is. Use of an acid generator that generates an acid having a bulky anion is also effective in reducing the influence of PPD. Acid proton is paired with anions, but proton hopping is reduced as the size of the anions increases.

Another component that is expected to be effective in reducing the effects of PPDs is the retainer. The development of the conventional quencher has been aimed at improving the contrast of the deprotection reaction by reducing the acid diffusion in the high-temperature PEB. However, in order to reduce the influence of the PPD, it is necessary to change the time point to effectively suppress the acid diffusion at room temperature The development of Keener is demanded.

[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2001-194776 [Patent Document 2] Japanese Unexamined Patent Publication No. 2002-226470 [Patent Document 3] Japanese Unexamined Patent Publication No. 2002-363148 [Patent Document 4] JP-A-2015-90382 [Patent Document 5] JP-A-2010-84144 [Patent Document 6] International Publication No. 2015/111640

SPIE Vol. 5039 p1 (2003) SPIE Vol. 6520 p65203L-1 (2007) SPIE Vol. 7639 p76390W (2010)

In order to suppress the influence of PPD, the addition of a quencher is effective, but in the case of the base generator in which the super strong base is generated as described in Patent Documents 5 and 6, the base is the exposure region. Since the diffusion of acid in the resist film during the room temperature after PEB is diffusion of the acid from the exposed portion to the unexposed portion, in the case of a mechanism where a basic substance is generated only in the exposed portion, acid diffusion from the exposed portion to the unexposed portion Can not be prevented.

A quencher such as an amine quencher, a sulfonic acid or a carboxylic acid sulfonium salt or an iodonium salt has a high basicity and has an effect of suppressing acid diffusion in the unexposed portion, but the performance is still insufficient. It is possible to suppress the acid diffusion at room temperature rather than the quench of a sulfonium salt or an iodonium salt of a sulfonic acid or a carboxylic acid, and further to provide a quencher having a high dissolution contrast and a reduced edge roughness (LWR) Development is required.

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a resist composition which has high dissolution contrast and low LWR even in a positive resist material and negative resist material, And a method of forming a pattern to be used.

DISCLOSURE OF THE INVENTION The inventors of the present invention have made intensive investigations in order to achieve the above object and as a result have found that a resist film having a small LWR and a high dissolution contrast and having no dimensional change in PPD can be obtained by using a predetermined oligomer salt compound as a quencher And finally completed the present invention.

Accordingly, the present invention provides the following resist material and a pattern forming method using the same.

1. A resist material comprising a base polymer and an asymmetric salt compound represented by the following formula (A).

Wherein R ¹ to R ⁸ each independently represent a hydrogen atom, a straight-chain, branched or cyclic alkyl group having 1 to 24 carbon atoms, a linear, branched or cyclic alkenyl group having 2 to 24 carbon atoms, An aryl group, an ether group, a sulfide group, a sulfoxide group, a carbonate group, a carbamate group, a sulfone group, an amino group R ¹ and R ² , R ² and R ³ , R ³ and R ⁴ , R ⁵ and R ⁶ , R ⁶ and R ⁷ , R ⁶ , R ⁷ and R ^{8 are the same as or different from each other} , Or R ⁷ and R ⁸ may combine to form a ring, and the ring may contain an ether bond. A ^- is a cation selected from the group consisting of hydroxide ion, chloride ion, bromide ion, iodide ion, nitrate ion, nitrite ion, chlorate ion, chlorite ion, perchlorate ion, hydrogen carbonate ion, hydrogenphosphate ion, A hydrogen ion, a cyanide ion, an iodic acid ion, or an anion represented by the following formula (M-1) or (M-2).

(Wherein R ⁹ represents a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms, a linear, branched or cyclic alkenyl group having 2 to 30 carbon atoms, a linear, An aralkyl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an aromatic or aliphatic heterocyclic containing group having 3 to 20 carbon atoms. Among these groups, an ester group, an ether group, a sulfide group R ⁹ is a group represented by the following formula (A) -1 (wherein R ¹ is a hydrogen atom, a halogen atom,

(Wherein Ar is an aromatic group having 6 to 16 carbon atoms; R ¹² and R ¹³ are each independently a hydrogen atom, a hydroxyl group, an alkoxy group, a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, Lt; / RTI >

Quot; is not included. R ¹⁰ is a fluorine atom, a linear, branched or cyclic fluorinated alkyl group having 1 to 10 carbon atoms, or a fluorinated phenyl group, and may contain a hydroxyl group, an ether group, an ester group or an alkoxy group. R ¹¹ is a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, a linear, branched or cyclic alkenyl group having 2 to 10 carbon atoms, a straight or branched alkynyl group having 2 to 10 carbon atoms, Or an aryl group having 6 to 10 carbon atoms, which may contain a hydroxyl group, an ether group, an ester group or an alkoxy group)

2. The resist material according to 1, further comprising an acid generator which generates a sulfonic acid, a sulfonimide or a sulfonimide.

3. A resist material according to 1 or 2, further comprising an organic solvent.

4. The resist material according to any one of 1 to 3, wherein the base polymer comprises a repeating unit represented by the following formula (a1) or a repeating unit represented by the following formula (a2).

Wherein R ³¹ and R ³³ are each independently a hydrogen atom or a methyl group, R ³² and R ³⁴ are each independently an acid labile group, X is a single bond, an ester group, a phenylene group, a naphthylene group, And Y is a single bond or an ester group.)

5. A resist material according to 4, further comprising a dissolution inhibitor.

6. A resist material as described in 4 or 5, which is a chemically amplified positive resist material.

7. The resist material according to any one of 1 to 3, wherein the base polymer does not contain an acid labile group.

8. The resist material according to 7, further comprising a crosslinking agent.

9. A resist material as described in 7 or 8 which is a chemically amplified negative resist material.

10. The resist material according to any one of 1 to 9, wherein the base polymer further comprises at least one repeating unit selected from the repeating units represented by the following formulas (f1) to (f3).

(Wherein R ⁵¹ , R ⁵⁵ and R ⁵⁹ are each independently a hydrogen atom or a methyl group, R ⁵² is a single bond, a phenylene group, -OR ⁶³ - or -C (= O) -Y ¹ -R ⁶³ - , Y ¹ is -O- or -NH-, and R ⁶³ is a linear, branched or cyclic, alkylene or alkenylene group having 1 to 6 carbon atoms which may contain a carbonyl group, an ester group, an ether group or a hydroxy group a, or a phenylene ^{group. R 53, R 54, R} 56, R 57, R 58, R 60, R 61 and R ⁶² are each independently a carbonyl group, a straight good having 1 to 12 carbon atoms optionally containing an ester group or ether chain, branched or cyclic alkyl group, or aryl group having a carbon number of 6-12, an aralkyl group, or mercapto group of a carbon number of 7~20. a ¹ represents a single ^{bond, -A 0 -C (= O)} -O- , -A ⁰ -O- or -A ⁰ -OC (= O) -, and A ⁰ represents a straight, branched or cyclic alkyl group having 1 to 12 carbon atoms which may contain a carbonyl group, an ester group or an ether group .. It is the alkylene group A ² is a hydrogen atom or a trifluoromethyl group Z ¹ is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenyl group, -OR ⁶⁴ -, or -C (= O) -Z ² -R ⁶⁴ -, Z ² is -O- or -NH-, and R ⁶⁴ is a straight, branched or cyclic, straight, branched or cyclic C 1-6 carbon atom which may contain a carbonyl group, an ester group, an ether group or a hydroxy group, an alkyl group or an alkenylene group, or a phenylene group, a fluorinated phenyl substituted with a methyl group as a group, or a trifluorophenyl group M ^-.. represents a non-nucleophilic counter ion is f1, f2 and f3 are 0≤f1≤0.5, 0? F2? 0.5, 0? F3? 0.5 and 0 <f1 + f2 + f3? 0.5.

11. A resist composition according to any one of 1 to 10, which further comprises a surfactant.

12. A pattern forming method comprising a step of applying a resist material described in any one of 1 to 11 on a substrate, a step of exposing the substrate to a high energy beam after the heat treatment, and a step of developing the resist material by using a developer.

13. The pattern forming method according to 12, wherein the high energy ray is an ArF excimer laser having a wavelength of 193 nm or a KrF excimer laser having a wavelength of 248 nm.

14. The pattern forming method according to 12, wherein the high energy beam is EB or EUV having a wavelength of 3 to 15 nm.

Since the resist film containing the biguanide salt compound has a high effect of suppressing acid diffusion and has a high dissolution contrast, the positive resist film in the alkali development, the negative resist film, and the negative resist film And has a good resolution and a wide focus margin. The LWR is small, and the dimensional change does not occur in the PPD.

[Resist material]

The resist material of the present invention includes a base polymer and a predetermined beginate salt compound. The above-mentioned biguanide salt compounds undergo ion exchange with a sulfonic acid, a sulfonimide or a sulfonimide generated from an acid generator, particularly a sulfonic acid containing a fluorinated alkyl group, a bissulfoneimide or a trisulfonimide to form a salt , Carboxylic acid or sulfonamide. Since the basicity of BIGUANIDE is very high, the effect of suppressing acid trapping ability and acid diffusion is high. The above-mentioned biguanide salt compound has no photosensitivity and does not generate an anhydride by light, and even an unexposed portion can sufficiently replenish the acid. Therefore, the diffusion of the acid from the exposed portion to the unexposed portion can be suppressed.

In the resist material of the present invention, other amine compound, ammonium salt, sulfonium salt or iodonium salt may be added as a quencher in addition to the above-mentioned biguanide salt compound. As the ammonium salt, sulfonium salt or iodonium salt to be added as a quencher at this time, sulfonium salts or iodonium salts of carboxylic acid, sulfonic acid, sulfonamide and saccharin are suitable. At this time, the carboxylic acid may be fluorinated or not fluorinated at the? -Position.

The acid diffusion inhibiting effect and contrast enhancement effect by the above-described beguinide salt compound are effective both in the positive pattern formation by the alkali development, in the negative pattern formation, and in the negative pattern formation in the organic solvent development.

[Biguanide salt compound]

The asymmetric salt compound contained in the resist material of the present invention is represented by the following formula (A).

In the formula (A), R ¹ to R ⁸ each independently represent a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 24 carbon atoms, a linear, branched or cyclic alkenyl group having 2 to 24 carbon atoms, Branched or cyclic alkynyl group having from 2 to 24 carbon atoms or an aryl group having from 6 to 20 carbon atoms, and an ester group, an ether group, a sulfide group, a sulfoxide group, a carbonate group, a carbamate group, R ¹ and R ² , R ² and R ³ , R ³ and R ⁴ , R ⁵ and R ⁶ , R ⁶ and R ⁷ may be the same or different and each independently represent a hydrogen atom, ⁷ or R &lt; ⁷ &gt; and R &lt; ⁸ &gt; may be combined to form a ring, and the ring may contain an ether bond.

In the formula (A), A ^- represents a cation selected from the group consisting of hydroxide ion, chloride ion, bromide ion, iodide ion, nitrate ion, nitrite ion, chlorate ion, chlorite ion, perchlorate ion, (M-1) or (M-2) shown below. The anion represented by the following formula (M-1) or (M-2)

Wherein R ⁹ represents a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms, a linear, branched or cyclic alkenyl group having 2 to 30 carbon atoms, a linear or branched alkyl group having 2 to 30 carbon atoms, Branched or cyclic alkynyl group, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an aromatic or aliphatic heterocyclic containing group having 3 to 20 carbon atoms. Among these groups, an ester group, an ether R ⁹ is a group represented by the following formulas (A) - (B), a sulfide group, a sulfoxide group, a carbonate group, a carbamate group, a sulfone group, an amino group, an amide group, a hydroxyl group, a thiol group, a nitro group and a halogen atom. One

(Wherein Ar is an aromatic group having 6 to 16 carbon atoms; R ¹² and R ¹³ are each independently a hydrogen atom, a hydroxyl group, an alkoxy group, a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, Lt; / RTI &gt;

Quot; is not included. In the formula (M-2), R ¹⁰ may be a fluorine atom, a linear, branched or cyclic fluorinated alkyl group having 1 to 10 carbon atoms, or a fluorinated phenyl group, and may contain a hydroxyl group, an ether group, an ester group or an alkoxy group. R ¹¹ is a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, a linear, branched or cyclic alkenyl group having 2 to 10 carbon atoms, a straight or branched alkynyl group having 2 to 10 carbon atoms, Or an aryl group having 6 to 10 carbon atoms, which may contain a hydroxyl group, an ether group, an ester group or an alkoxy group.

Examples of the anion of the carboxylate represented by the formula (M-1) include, but are not limited to, the following.

Examples of the anion of the sulfonamide salt represented by the formula (M-2) include, but are not limited to, the following.

The cation of the asymmetric salt salt compound represented by the formula (A) includes, but is not limited to, the following.

The positive charge of the cationized acetonide is localized to five nitrogen atoms. For this reason, there are points for trapping and neutralizing anions of sulfonic acid, sulfonimide, and sulfonimide everywhere, so that anions can be quickly trapped. BGG is an excellent retainer with high trapping ability for high basicity.

Examples of the method for synthesizing an acetonide salt compound represented by the formula (A) include a method of mixing a carboxylic acid or a sulfonamide with an acetonide compound obtained by reacting guanidines and carbodiimides. Such a method is described in detail, for example, in International Publication No. 2015/111640.

The content of the asymmetric salt compound represented by the formula (A) in the resist composition of the present invention is preferably 0.001 to 50 parts by mass relative to 100 parts by mass of the base polymer in terms of sensitivity and acid diffusion suppressing effect, More preferably 0.01 to 20 parts by mass.

[Base polymer]

The base polymer included in the resist material of the present invention includes a repeating unit containing an acid labile group in the case of a positive resist composition. The repeating unit containing an acid labile group is preferably a repeating unit represented by the following formula (a1) (hereinafter referred to as a repeating unit a1) or a repeating unit represented by the formula (a2) (hereinafter referred to as a repeating unit a2) Do.

Wherein R ³¹ and R ³³ are each independently a hydrogen atom or a methyl group. R ³² and R ³⁴ are each independently an acid labile group. X is a linking group having 1 to 12 carbon atoms including a single bond, an ester group, a phenylene group, a naphthylene group or a lactone ring, but a single bond, a phenylene group or a naphthylene group is preferable. Y is a single bond or an ester group, but a single bond is preferable.

The repeating unit a1 includes, but is not limited to, those shown below. In the following formulas, R ³¹ and R ³² are as defined above.

As the acid labile groups represented by R ³² and R ³⁴ in the repeating units a 1 and a 2, various acid labile groups are selected. For example, the acid labile groups described in JP-A-2013-80033 and JP-A-2013-83821 can be used .

Typically, the acid labile groups represented by the following formulas (AL-1) to (AL-3) may be mentioned.

In the formulas (AL-1) and (AL-2), R ³⁵ and R ³⁸ are monovalent hydrocarbon groups of 1 to 40 carbon atoms, particularly 1 to 20 carbon atoms, such as straight, branched, or cyclic alkyl groups, , A sulfur atom, a nitrogen atom, and a fluorine atom. R ³⁶ and R ³⁷ are each independently a hydrogen atom or a monovalent hydrocarbon group such as a straight, branched or cyclic alkyl group of 1 to 20 carbon atoms, and is a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom or a fluorine atom . A1 is an integer of 0 to 10, particularly 1 to 5; R ³⁶ and R ³⁷ , R ³⁶ and R ³⁸ , or R ³⁷ and R ³⁸ are bonded to each other to form a carbon atom or a ring having 3 to 20 carbon atoms, preferably 4 to 16 carbon atoms, Or an alicyclic ring may be formed.

In the formula (AL-3), R ³⁹ , R ⁴⁰ and R ⁴¹ are each independently a monovalent hydrocarbon group of 1 to 20 carbon atoms such as a linear, branched or cyclic alkyl group and is an oxygen atom, a sulfur atom, , And a hetero atom such as a fluorine atom. R ³⁹ and R ⁴⁰ , R ³⁹ and R ⁴¹ , or R ⁴⁰ and R ⁴¹ may combine with each other to form a ring having 3 to 20 carbon atoms, preferably 4 to 16 carbon atoms, in particular an alicyclic ring, together with the carbon atoms to which they are bonded .

The base polymer may further contain a repeating unit b containing a phenolic hydroxyl group as a bonding agent. Examples of the monomer giving the repeating unit b include, but are not limited to, the following.

The base polymer may further contain, as another adhesive group, a repeating unit c containing a hydroxy group other than the phenolic hydroxy group, a lactone ring, an ether group, an ester group, a carbonyl group or a cyano group. Examples of the monomer giving the repeating unit c include, but are not limited to, the following.

In the case of a monomer containing a hydroxyl group, the hydroxy group may be replaced with an acetal group which is easily deprotected by an acid such as an ethoxyethoxy group during polymerization and then deprotected by weak acid and water after polymerization. And the alkali hydrolysis may be carried out after the polymerization by substituting pivaloyl groups with pivaloyl groups.

The base polymer may further include a repeating unit d derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene or a derivative thereof. Examples of the monomer giving the repeating unit d include, but are not limited to, the following.

The base polymer may further include a repeating unit e derived from styrene, vinyl naphthalene, vinyl anthracene, vinyl pyrene, methylene indane, vinyl pyridine or vinyl carbazole.

The base polymer may further contain a repeating unit f derived from an onium salt containing a polymerizable carbon-carbon double bond. Japanese Patent Application Laid-Open No. 2005-84365 proposes a sulfonium salt or an iodonium salt containing a polymerizable carbon-carbon double bond which generates a specific sulfonic acid. Japanese Patent Application Laid-Open No. 2006-178317 proposes a sulfonium salt in which a sulfonic acid is directly bonded to a main chain.

Preferred examples of the repeating unit f include repeating units represented by the following formulas (f1), (f2) and (f3) (hereinafter referred to as repeating units f1, repeating units f2 and repeating units f3). The repeating units f1 to f3 may be used singly or in combination of two or more.

Wherein R ⁵¹ , R ⁵⁵ and R ⁵⁹ are each independently a hydrogen atom or a methyl group. R ⁵² is a single bond, a phenylene group, -OR ⁶³ - or -C (= O) -Y ¹ -R ⁶³ -, Y ¹ is -O- or -NH- and R ⁶³ is a carbonyl group, Branched or cyclic, alkylene or alkenylene group having 1 to 6 carbon atoms which may contain a hydroxyl group or a hydroxy group, or a phenylene group. R ⁵³ , R ⁵⁴ , R ⁵⁶ , R ⁵⁷ , R ⁵⁸ , R ⁶⁰ , R ⁶¹ and R ⁶² each independently represents a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms which may contain a carbonyl group, An aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or a mercaptophenyl group. A ¹ is a single bond, -A ⁰ -C (═O) -O-, -A ⁰ -O- or -A ⁰ -OC (═O) -, A ⁰ includes a carbonyl group, an ester group or an ether group Branched or cyclic alkylene group having 1 to 12 carbon atoms which may be substituted or unsubstituted. A ² is a hydrogen atom or a trifluoromethyl group. Z ¹ represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, -OR ⁶⁴ - or -C (= O) -Z ² -R ⁶⁴ -, Z ² represents -O- or -NH- , R ⁶⁴ is a linear, branched or cyclic alkylene or alkenylene group having 1 to 6 carbon atoms which may contain a carbonyl group, an ester group, an ether group or a hydroxy group, or a phenylene group, a fluorinated phenylene group, A phenylene group substituted with a trifluoromethyl group. M ^- represents an unconjugated counter ion. f1, f2 and f3 are positive numbers satisfying 0? f1? 0.5, 0? f2? 0.5, 0? f3? 0.5 and 0 <f1 + f2 + f3?

The monomer giving the repeating unit f1 includes, but is not limited to, the following. In the formula, M ^- represents an unconjugated counter ion.

Examples of the non-nucleophilic counter ion represented by M ^- include halide ions such as chloride ion and bromide ion, fluoroalkylsulfone such as triflate, 1,1,1-trifluoroethanesulfonate and nonafluorobutanesulfonate Alkylsulfonates such as methanesulfonate, butanesulfonate, and the like; arylsulfonates such as benzylsulfonate, naphthylsulfonate, benzylsulfonate, 4-fluorobenzenesulfonate and 1,2,3,4,5-pentafluorobenzenesulfonate; , Bis (trifluoromethylsulfonyl) imide, bis (perfluoroethylsulfonyl) imide and bis (perfluorobutylsulfonyl) imide, and tris (trifluoromethylsulfonyl) ) Methide, and tris (perfluoroethylsulfonyl) methide.

As the non-nucleophilic counter ion, a sulfonic acid ion represented by the following formula (K-1) wherein the? -Position is fluoro-substituted, a sulfonic acid ion represented by the following formula (K-2) And the like.

In the formula (K-1), R ⁶⁵ represents a hydrogen atom, a straight chain, branched or cyclic alkyl group having 1 to 20 carbon atoms, a straight chain, branched or cyclic alkenyl group having 2 to 20 carbon atoms, An aryl group, an ether group, an ester group, a carbonyl group, a lactone ring or a fluorine atom.

In the formula (K-2), R ⁶⁶ represents a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms, a linear, branched or cyclic acyl group having 1 to 30 carbon atoms, Branched or cyclic alkenyl group, an aryl group having 6 to 20 carbon atoms, or an aryloxy group having 6 to 20 carbon atoms, and may contain an ether group, an ester group, a carbonyl group or a lactone ring.

Examples of the monomer giving the repeating unit f2 include, but are not limited to, the following.

Examples of the monomer giving the repeating unit f3 include, but are not limited to, the following.

By bonding an acid generator to the polymer main chain, it is possible to reduce the acid diffusion and prevent degradation of the resolution due to fogging by acid diffusion. In addition, the edge roughness is improved by uniformly dispersing the acid generator. When a base polymer containing at least one repeating unit selected from the repeating units f1 to f3 is used, the mixing of the photoacid generator to be described later can be omitted.

As the base polymer for a positive resist material, a repeating unit a1 or a2 including an acid labile group is essential. In this case, the content ratios of the repeating units a1, a2, b, c, d, e, f1, f2 and f3 satisfy 0? A1 <1.0, 0? A2 <1.0, 0 <a1 + a2 <1.0, ? 0.9, 0? C? 0.9, 0? D? 0.8, 0? E? 0.8, 0? F1? 0.5, 0? F2? 0.5 and 0? F3? 0.5, 0.8, 0? d? 0.7, 0? e? 0.7, 0? f1? 0.4, 0? f2? 0.4 and 0? f3? 0.4, more preferably 0? a1? 0.8, 0? a2? 0.8, 0.1? a1 + a2? 0.8, 0? b? 0.75, 0? c? 0.75, 0? d? 0.6, 0.6, 0? F1? 0.3, 0? F2? 0.3 and 0? F3? 0.3 are more preferable. Further, a1 + a2 + b + c + d + e + f1 + f2 + f3 = 1.0.

On the other hand, a base polymer for a negative resist material does not necessarily require a fire retardant. Examples of such a base polymer include repeating units b and, if necessary, further containing repeating units c, d, e, f1, f2 and / or f3. The content ratio of these repeating units is 0 <b? 1.0, 0? C? 0.9, 0? D? 0.8, 0? E? 0.8, 0? F1? 0.5, 0? F2? 0.5 and 0? F3? , Preferably 0.2? B? 1.0, 0? C? 0.8, 0? D? 0.7, 0? E? 0.7, 0? F1? 0.4, 0? F2? 0.4 and 0? F3? 0.4, 0.3? B? 1.0, 0? C? 0.75, 0? D? 0.6, 0? E? 0.6, 0? F1? 0.3, 0? F2? 0.3 and 0? F3? 0.3. Further, b + c + d + e + f1 + f2 + f3 = 1.0.

In order to synthesize the base polymer, for example, a monomer for imparting the above-mentioned repeating unit may be subjected to heat polymerization by adding a radical polymerization initiator in an organic solvent.

Examples of the organic solvent used in the polymerization include toluene, benzene, tetrahydrofuran, diethyl ether, and dioxane. Examples of the polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis (2,4-dimethylvaleronitrile), dimethyl 2,2-azobis Nate), benzoyl peroxide, and lauroyl peroxide. The temperature at the time of polymerization is preferably 50 to 80 占 폚. The reaction time is preferably 2 to 100 hours, more preferably 5 to 20 hours.

When hydroxystyrene or hydroxyvinylnaphthalene is copolymerized, acetoxystyrene or acetoxyvinylnaphthalene is used instead of hydroxystyrene or hydroxyvinylnaphthalene, and after the polymerization, the acetoxy group is deprotected by the above-mentioned alkali hydrolysis And hydroxystyrene or hydroxyvinylnaphthalene may be used.

As the base upon alkali hydrolysis, ammonia water, triethylamine and the like can be used. The reaction temperature is preferably -20 to 100 占 폚, more preferably 0 to 60 占 폚. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

The base polymer preferably has a weight average molecular weight (Mw) in terms of polystyrene by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent, preferably 1,000 to 500,000, more preferably 2,000 to 30,000 . If the Mw is too small, the resist material tends to have poor heat resistance. If the Mw is excessively large, the alkali solubility tends to deteriorate and a footing phenomenon tends to occur after pattern formation.

Further, when the molecular weight distribution (Mw / Mn) of the base polymer is wide, there is a fear that foreign matter may be seen on the pattern or the shape of the pattern may deteriorate after exposure, because a polymer having a low molecular weight or a high molecular weight exists have. In order to obtain a resist material suitably used for fine pattern dimensions, the molecular weight distribution of the base polymer is 1.0 to 2.0, particularly 1.0 to 1.5, and the narrow distribution .

The base polymer may include two or more polymers having different composition ratios, Mw, and molecular weight distribution.

[Acid generator]

By adding an acid generator to the resist composition containing the base polymer and an asymmetric salt compound represented by the formula (A), the resist composition can function as a chemically amplified positive resist or a chemically amplified negative resist. Examples of the acid generator include a compound (photo-acid generator) that generates an acid in response to an actinic ray or radiation. As the photoacid generator, any compound capable of generating an acid by irradiation with high energy radiation may be used, but it is preferable that a sulfonic acid, a sulfonimide or a sulfonimide is generated. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, oxime-O-sulfonate acid generators, and the like. Specific examples of the photoacid generator include those described in paragraphs [0122] to [0142] of Japanese Patent Application Laid-Open No. 2008-111103.

As the photoacid generator, those represented by the following formula (1) or (2) can also be suitably used.

In the formula (1), R ¹⁰¹ , R ¹⁰² and R ¹⁰³ each independently represents a linear, branched or cyclic monovalent hydrocarbon group of 1 to 20 carbon atoms which may contain a hetero atom. Any two of R ¹⁰¹ , R ¹⁰² and R ^{103 may} be bonded to each other to form a ring together with the sulfur atom to which they are bonded.

In the formula (1), X ^- represents an anion selected from the following formulas (1A) to (1D).

Formula (1A) of, R ^fa is may contain a fluorine atom, or a heteroatom of a great number of carbon atoms from 1 to 40 linear, branched or cyclic hydrocarbon group of 1.

The anion represented by the formula (1A) is preferably represented by the following formula (1A ').

In the formula (1A '), R ¹⁰⁴ represents a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. R ¹⁰⁵ represents a linear, branched or cyclic monovalent hydrocarbon group of 1 to 38 carbon atoms which may contain a hetero atom. The hetero atom is preferably an oxygen atom, a nitrogen atom, a sulfur atom or a halogen atom, and more preferably an oxygen atom. The monovalent hydrocarbon group preferably has 6 to 30 carbon atoms, in particular, from the viewpoint of obtaining a high resolution in forming a fine pattern. Examples of the monovalent hydrocarbon group include monovalent hydrocarbon groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, an s-butyl group, a t-butyl group, a pentyl group, a neopentyl group, a cyclopentyl group, An isoamyl group, a 1-adamantyl group, a 1-adamantyl group, a 1-adamantyl group, a 2-ethylhexyl group, An allyl group, a benzyl group, a diphenylsulfonyl group, a benzyl group, a benzyl group, a benzyl group, a benzyl group, a benzyl group, a benzyl group, (2-methoxyethoxy) methyl group, an acetoxymethyl group, a 2-carboxy-1-cyclohexyl group, a 2-methoxyethoxy group, a 2- A 2-oxopropyl group, a 4-oxo-1-adamantyl group, and a 3-oxocyclohexyl group. . A part of the hydrogen atoms of these groups may be substituted with a heteroatom-containing group such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, or an oxygen atom, a sulfur atom, a nitrogen atom A carbonyl group, an ether group, an ester group, a sulfonate group, a carbonate group, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group and the like may be interposed between the May be included.

With respect to the synthesis of a sulfonium salt containing an anion represented by the formula (1A '), JP-A No. 2007-145797, JP-A No. 2008-106045, JP-A No. 2009-7327, Japanese Patent Application Laid-Open No. 2009-258695 and the like. Sulfonium salts described in JP-A-2010-215608, JP-A-2012-41320, JP-A-2012-106986, and JP-A-2012-153644 are suitably used .

Examples of the sulfonium salt containing an anion represented by the formula (1A) include, but are not limited to, the following sulfonium salts. In the following formulas, Ac represents an acetyl group and Ph represents a phenyl group.

In formula (1B), R ^fb1 and R ^fb2 each independently represent a straight, branched or cyclic monovalent hydrocarbon group of 1 to 40 carbon atoms which may contain a fluorine atom or a hetero atom. Examples of the monovalent hydrocarbon group include the same monovalent hydrocarbon groups as those described in the description of R ¹⁰⁵ . R ^fb1 and R ^fb2 are preferably a fluorine atom or a straight chain fluorinated alkyl group having 1 to 4 carbon atoms. In addition, R ^fb1 and ^fb2 R is a group to which they are bonded ^{_{(-CF 2 -SO 2 -N - -SO}} 2 -CF 2 -) may be formed with a ring, in particular fluorinated or fluorinated ethylene propylene group It is preferable to form a ring structure.

In the formula (1C), R ^fc1 , R ^fc2 and R ^fc3 each independently represent a straight, branched or cyclic monovalent hydrocarbon group of 1 to 40 carbon atoms which may contain a fluorine atom or a hetero atom. Examples of the monovalent hydrocarbon group include the same monovalent hydrocarbon groups as those described in the description of R ¹⁰⁵ . R ^fc1 , R ^fc2 and R ^fc3 are preferably a fluorine atom or a straight-chain fluorinated alkyl group having 1 to 4 carbon atoms. R ^fc1 and R ^fc2 may be bonded to each other to form a ring together with the group (-CF ₂ -SO ₂ -C ^- -SO ₂ -CF ₂ -) to which they are bonded, and in particular, a ring may be formed by a fluorinated ethylene group or a fluorinated propylene group Structure is preferably formed.

In the formula (1D), R ^fd represents a linear, branched or cyclic monovalent hydrocarbon group of 1 to 40 carbon atoms which may contain a hetero atom. Examples of the monovalent hydrocarbon group include the same monovalent hydrocarbon groups as those described in the description of R ¹⁰⁵ .

The synthesis of a sulfonium salt containing an anion represented by the formula (1D) is described in detail in JP-A-2010-215608 and JP-A-2014-133723.

Examples of the sulfonium salt containing an anion represented by the formula (1D) include, but are not limited to, the following sulfonium salts. In the formula, Ph represents a phenyl group.

Further, the photoacid generator containing an anion represented by the formula (1D) does not have fluorine at the? -Position of the sulfo group but has two trifluoromethyl groups at the? -Position, It has sufficient acidity to cut the ballast. Therefore, it can be used as a photoacid generator.

In formula (2), R ²⁰¹ and R ²⁰² each independently represents a linear, branched or cyclic monovalent hydrocarbon group of 1 to 30 carbon atoms which may contain a hetero atom. R ²⁰³ represents a linear, branched or cyclic divalent hydrocarbon group of 1 to 30 carbon atoms which may contain a hetero atom. Any two of R ²⁰¹ , R ²⁰² and R ^{203 may} be bonded to each other to form a ring together with the sulfur atom to which they are bonded. L ^A represents a straight-chain, branched or cyclic divalent hydrocarbon group of 1 to 20 carbon atoms which may contain a single bond, an ether group or a hetero atom. X ^A , X ^B , X ^C and X ^D each independently represent a hydrogen atom, a fluorine atom or a trifluoromethyl group. Provided that at least one of X ^A , X ^B , X ^C and X ^D represents a substituent other than a hydrogen atom. k represents an integer of 0 to 3;

Examples of the monovalent hydrocarbon group include monovalent hydrocarbon groups such as methyl, ethyl, propyl, isopropyl, n-butyl, s-butyl, A cyclohexyl group, a cyclohexyl group, a cyclohexyl group, a cyclopentyl group, a cyclopentyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexyl group, a cyclohexyl group, a cyclohexyl group, Butyl group, norbornyl group, oxanorbornyl group, tricyclo [5.2.1.0 ^2,6 ] decanyl group, adamantyl group, phenyl group, naphthyl group and anthracenyl group. A part of the hydrogen atoms of these groups may be substituted with a heteroatom-containing group such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, or a part of carbon atoms may be substituted with a hetero atom such as an oxygen atom, May contain a hydroxyl group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a lactone ring, a carboxylic acid anhydride, a haloalkyl group and the like.

Examples of the divalent hydrocarbon group include a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, -1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane- Diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane- A straight chain alkanediyl group such as a 17-diyl group; A saturated cyclic divalent hydrocarbon group such as a cyclopentanediyl group, a cyclopentanediyl group, a cyclohexanediyl group, a norbornanediyl group, and an adamantanediyl group; And unsaturated cyclic divalent hydrocarbon groups such as a phenylene group and a naphthylene group. A part of the hydrogen atoms of these groups may be substituted with an alkyl group such as a methyl group, an ethyl group, a propyl group, an n-butyl group or a t-butyl group. A part of the hydrogen atoms of these groups may be substituted with a heteroatom-containing group such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, or an oxygen atom, a sulfur atom, a nitrogen atom Containing groups such as a hydroxyl group, a cyano group, a carbonyl group, an ether group, an ester group, a sulfonic acid ester group, a carbonate group, a lactone ring, a lactone ring, a carboxylic acid anhydride, a haloalkyl group and the like It may be. The hetero atom is preferably an oxygen atom.

The photoacid generator represented by the formula (2) is preferably represented by the following formula (2 ').

In formula (2 '), L ^A is the same as above. R represents a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. R ³⁰¹ , R ³⁰² and R ³⁰³ each independently represents a hydrogen atom or a straight, branched or cyclic monovalent hydrocarbon group of 1 to 20 carbon atoms which may contain a hetero atom. Examples of the monovalent hydrocarbon group include the same monovalent hydrocarbon groups as those described in the description of R ¹⁰⁵ . x and y each independently represent an integer of 0 to 5, and z represents an integer of 0 to 4.

Examples of the photoacid generator represented by the formula (2) include, but are not limited to, the following. In the following formulas, R is as defined above, and Me represents a methyl group.

Among the above-mentioned photoacid generators, those containing anions represented by the formula (1A ') or (1D) are particularly preferable because of their small acid diffusion and excellent solubility in a resist solvent. Including the anion represented by the formula (2 ') is particularly preferable because the acid diffusion is very small.

The blending amount of the acid generator is preferably 0.1 to 50 parts by mass, more preferably 1 to 40 parts by mass, per 100 parts by mass of the base polymer.

[Other components]

A solution of an organic solvent, a surfactant, a dissolution inhibitor, a crosslinking agent, and the like is added to a chemically amplified positive resist material or a chemically amplified negative resist material containing an asymmetric salt salt compound represented by the formula (A), a base polymer and an acid generator , A positive resist material and a negative resist material are constituted so that the dissolution rate of the base polymer in the developer is accelerated by the catalytic reaction in the exposure section, A negative type resist material can be used. In this case, the resist film has high dissolution contrast and resolution, has an exposure margin, is excellent in process adaptability, has a good pattern shape after exposure, can suppress acid diffusion in particular, and has a small dense dimension difference. It is highly practical and can be very effective as a resist material for a super LSI. In particular, when a chemically amplified positive resist material containing an acid generator and containing acid catalyzed reaction is used, the sensitivity can be made higher, and the characteristics are further improved, which is very useful.

In the case of a positive type resist material, by mixing a dissolution inhibitor, the difference in dissolution rate between the exposed portion and the unexposed portion can be further increased, and the resolution can be further improved. In the case of a negative resist material, a negative pattern can be obtained by reducing the dissolution rate of the exposed portion by adding a crosslinking agent.

Examples of the organic solvent include ketones such as cyclohexanone, cyclopentanone and methyl-2-n-pentyl ketone described in paragraphs [0144] to [0145] of JP-A No. 2008-111103, ketones such as 3-methoxy Butanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol and 1-ethoxy-2-propanol, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl Propylene glycol monomethyl ether acetate, propyleneglycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, 3-methoxyphenol, and the like; an ether such as ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; Esters such as methyl propionate, ethyl 3-ethoxypropionate, t-butyl acetate, t-butyl propionate and propylene glycol mono-t-butyl ether acetate, And mixtures thereof.

The blending amount of the organic solvent is preferably 100 to 10,000 parts by mass, more preferably 200 to 8,000 parts by mass with respect to 100 parts by mass of the base polymer.

Examples of the surfactant include those described in paragraphs [0165] to [0166] of Japanese Patent Application Laid-Open No. 2008-111103. By adding a surfactant, the applicability of the resist material can be further improved or controlled. The blending amount of the surfactant is preferably 0.0001 to 10 parts by mass based on 100 parts by mass of the base polymer.

The dissolution inhibitor preferably has a molecular weight of from 100 to 1,000, more preferably from 150 to 800, and the hydrogen atom of the phenolic hydroxyl group of the compound containing two or more phenolic hydroxyl groups in the molecule is protected by an acid- A compound obtained by substituting the hydrogen atoms of these carboxyl groups of the compound containing a carboxyl group in the molecule with an acid-labile group in an overall ratio of 50 to 100 mol% on the whole. Specific examples thereof include compounds obtained by replacing hydrogen atoms of hydroxyl groups and carboxyl groups of bisphenol A, trisphenol, phenolphthalein, cresol novolak, naphthalenecarboxylic acid, adamantanecarboxylic acid, and cholic acid with acid labile groups, , And Japanese Patent Application Laid-Open No. 2008-122932, paragraphs [0155] to [0178].

The blending amount of the dissolution inhibitor is preferably from 0 to 50 parts by mass, more preferably from 5 to 40 parts by mass, per 100 parts by mass of the base polymer in the case of the positive resist composition.

Examples of the crosslinking agent include an epoxy compound, a melamine compound, a guanamine compound, a glycoluril compound or a urea compound, an isocyanate compound, an azide compound and an alkenyl ether group substituted with at least one group selected from methylol group, alkoxymethyl group and acyloxymethyl group And the like, and the like. These may be used as an additive, but may be introduced as a pendant group in the polymer side chain. In addition, a compound containing a hydroxy group can also be used as a crosslinking agent.

Examples of the epoxy compound include tris (2,3-epoxypropyl) isocyanurate, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, and triethylolethane triglycidyl ether.

Examples of the melamine compound include compounds obtained by methoxymethylating one to six methylol groups of hexamethylol melamine, hexamethoxymethyl melamine, and hexamethylol melamine, or mixtures thereof, hexamethoxyethyl melamine, hexaacyloxymethyl melamine, hexa A compound obtained by acyloxymethylating 1 to 6 methylol groups of methylol melamine, and mixtures thereof.

Examples of the guanamine compound include compounds obtained by methoxymethylating 1 to 4 methylol groups of tetramethylolguanamine, tetramethoxymethylguanamine and tetramethylolguanamine, or mixtures thereof, tetramethoxyethylguanamine, tetraacyloxy A compound obtained by acyloxymethylating 1 to 4 methylol groups of guanamine or tetramethylolguanamine, or a mixture thereof.

Examples of the glycoluril compound include compounds obtained by methoxymethylating 1 to 4 methylol groups of tetramethylol glycoluril, tetramethoxyglycoluril, tetramethoxymethylglycoluril and tetramethylolglycoluril, or mixtures thereof, tetramethylol glycol A compound obtained by acyloxymethylating 1 to 4 of the methyl groups in the uril, or a mixture thereof. Examples of the urea compound include tetramethylol urea, tetramethoxymethyl urea, a compound in which 1 to 4 methylol groups of tetramethylol urea are methoxymethylated or a mixture thereof, and tetramethoxyethyl urea.

Examples of the isocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and cyclohexane diisocyanate.

Examples of the azide compound include 1,1'-biphenyl-4,4'-bisazide, 4,4'-methylidenebisazide, and 4,4'-oxybisazide.

Examples of the compound containing an alkenyl ether group include ethylene glycol divinyl ether, triethylene glycol divinyl ether, 1,2-propanediol divinyl ether, 1,4-butanediol divinyl ether, tetramethylene glycol divinyl ether, neopentyl Cyclohexanediol divinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, sorbitol tetravinyl ether, sorbitol penta-vinyl ether, stearyl divinyl ether, trimethylol propane trivinyl ether, hexanediol divinyl ether, , Trimethylolpropane trivinyl ether, and the like.

The amount of the crosslinking agent to be blended is preferably from 0.1 to 50 parts by mass, more preferably from 1 to 40 parts by mass, per 100 parts by mass of the base polymer in the case of a negative resist composition.

The resist material of the present invention may contain a quencher (hereinafter referred to as another quencher) other than the asymmetric salt compound represented by the formula (A). As other quenchers, there may be mentioned conventional basic compounds. As the conventional basic compound, there may be mentioned a primary compound, a secondary compound or a tertiary aliphatic amine, a mixed amine, an aromatic amine, a heterocyclic amine, a nitrogen-containing compound having a carboxyl group, a nitrogen-containing compound having a sulfonyl group, A nitrogen-containing compound having a hydroxyphenyl group, an alcoholic nitrogen-containing compound, an amide, an imide, and a carbamate. Particularly, the amine compounds of the first, second, and third classes described in paragraphs [0146] to [0164] of JP-A No. 2008-111103, especially hydroxyl groups, ether groups, ester groups, lactone rings, An amine compound having a sulfonic acid ester group, or a compound having a carbamate group described in Japanese Patent No. 3790649 are preferable. By adding such a basic compound, for example, the diffusion rate of the acid in the resist film can be further suppressed or the shape can be corrected.

Examples of other quenchers include onium salts of sulfonic acids and carboxylic acids in which the? -Position is not fluorinated, such as sulfonium salts, iodonium salts, and ammonium salts, described in JP-A-2008-158339 . The sulfonic acid, sulfonimide or sulfonimide in which the α-position is fluorinated is necessary for deprotecting the acid-labile group of the carboxylic acid ester, but the α-position is fluorinated by salt exchange with the non-fluorinated onium salt at the α- A sulfonic acid or a carboxylic acid is released. The sulfonic acid and the carboxylic acid in which the? -position is not fluorinated function as a quencher since they do not cause a deprotection reaction.

Other examples of the quencher include the polymer type quencher disclosed in Japanese Patent Application Laid-Open No. 2008-239918. This improves the squareness of the resist after the pattern by orienting the resist on the surface of the resist after coating. The polymer-type retainer also has an effect of preventing film thickness reduction and rounding of the pattern top when a protective film for liquid immersion exposure is applied.

The amount of other quencher is preferably 0 to 5 parts by mass, more preferably 0 to 4 parts by mass, per 100 parts by mass of the base polymer.

The resist material of the present invention may be blended with a polymer compound (water repellency improving agent) for improving the water repellency of the resist surface after spin coating. The water repellency improving agent can be used for immersion lithography that does not use a topcoat. The water repellency improving agent is preferably a polymer compound containing an alkyl fluoride group, a polymer compound containing a 1,1,1,3,3,3-hexafluoro-2-propanol residue of a specific structure, and the like, -297590, and Japanese Patent Laid-Open Publication No. 2008-111103. The water repellency improving agent needs to be dissolved in an organic solvent developer. The water repellency improving agent having the above-mentioned specific 1,1,1,3,3,3-hexafluoro-2-propanol residue has good solubility in a developing solution. As the water repellency improving agent, a polymer compound containing a repeating unit containing an amino group or an amine salt has a high effect of preventing evaporation of an acid in PEB and preventing defective opening of a hole pattern after development. The blending amount of the water repellency-improving agent is preferably 0 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, per 100 parts by mass of the base polymer.

Acetylene alcohols may be blended in the resist material of the present invention. Examples of the acetylene alcohols include those described in paragraphs [0179] to [0182] of JP-A No. 2008-122932. The blending amount of acetylene alcohols is preferably 0 to 5 parts by mass relative to 100 parts by mass of the base polymer.

[Pattern formation method]

When the resist material of the present invention is used in the manufacture of various integrated circuits, well-known lithography techniques can be applied.

For example, the positive type resist material of the present invention can be used as a substrate for producing an integrated circuit (Si, SiO ₂ , SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflection film, CrON, MoSi ₂ or the like) by a suitable coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating or the like so as to have a coating film thickness of 0.1 to 2.0 μm. This is prebaked on a hot plate, preferably at 60 to 150 DEG C for 10 seconds to 30 minutes, more preferably at 80 to 120 DEG C for 30 seconds to 20 minutes. Subsequently, a desired pattern is exposed to a desired pattern through a predetermined mask or directly with a high-energy beam such as ultraviolet light, far ultraviolet ray, EB, EUV, X-ray, soft X-ray, excimer laser, gamma ray or synchrotron radiation. The exposure dose is preferably about 1 to 200 mJ / cm 2, particularly about 10 to 100 mJ / cm 2, or about 0.1 to 100 μC / cm 2, particularly 0.5 to 50 μC / cm 2. Then, PEB is carried out on a hot plate, preferably at 60 to 150 캜 for 10 seconds to 30 minutes, more preferably at 80 to 120 캜 for 30 seconds to 20 minutes.

In addition, it is preferable to use tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide A dip method, a puddle method, a spray method, or the like using a developing solution of an aqueous alkali solution such as sodium hydroxide, potassium hydroxide (TBAH) or the like for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes By developing by a conventional method, the portion irradiated with light is dissolved in the developer, and the unexposed portion is not dissolved, and a desired positive pattern is formed on the substrate. In the case of a negative resist, the opposite of the case of the positive resist, that is, the portion irradiated with light is insoluble in the developer, and the portion not exposed is dissolved. Further, the resist material of the present invention is particularly suitable for fine patterning by a KrF excimer laser, an ArF excimer laser, EB, EUV, X-ray, soft X-ray, gamma ray or synchrotron radiation even in a high energy beam.

It is also possible to perform negative development to obtain a negative pattern by organic solvent development using a positive type resist material including a base polymer containing an acid labile group. Examples of the developing solution used in this case include 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutylketone, methylcyclohexa Butyronitrile, isopentyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl valerate, ethyl valerate, ethyl valerate, , Methyl pentanoate, 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 Benzyl benzoate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, propyl 3-phenylpropionate, methyl 3-phenylpropionate, ethyl 3-phenylpropionate, And the like acid benzyl, phenyl ethyl acetate, 2-phenylethyl. These organic solvents may be used singly or in combination of two or more kinds.

At the end of development, rinsing is performed. As the rinse solution, a solvent which does not dissolve the resist film by mixing with the developer is preferable. As such a solvent, an alcohol of 3 to 10 carbon atoms, an ether compound of 8 to 12 carbon atoms, an alkane of 6 to 12 carbon atoms, an alkene, an alkyne, and an aromatic solvent are preferably used.

Specific examples of the alcohol having 3 to 10 carbon atoms include n-propyl alcohol, isopropyl alcohol, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, t- Butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol 3-dimethyl-2-butanol, 3-dimethyl-1-butanol, Methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4- Methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol and 1-octanol.

Examples of the ether compound having from 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, di-s-butyl ether, di-n-pentyl ether, diisopentyl ether, di- N-hexyl ether, pentyl ether and di-n-hexyl ether.

Examples of the alkane having 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, Nonan, and the like. Examples of the alkene having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene and the like. Examples of the alkyne having 6 to 12 carbon atoms include hexyne, heptyne, octyne and the like.

Examples of the aromatic solvents include toluene, xylene, ethylbenzene, isopropylbenzene, t-butylbenzene, and mesitylene.

By rinsing, the occurrence of collapse of the resist pattern and the occurrence of defects can be reduced. In addition, rinsing is not absolutely necessary, and the amount of solvent used can be reduced by not rinsing.

The hole pattern or trench pattern after development can also be shrunk by thermal flow, RELACS technology or DSA technology. The water-shrinking agent is applied on the hole pattern, the diffusion of the acid-catalyzed agent from the resist layer in the bake causes the crosslinking of the water-shrinking agent on the surface of the resist, and the water-shrinking agent is attached to the side wall of the hole pattern. The baking temperature is preferably 70 to 180 DEG C, more preferably 80 to 170 DEG C, and the time is preferably 10 to 300 seconds, and the hole pattern is reduced by eliminating the excess water reducing agent.

Example

Hereinafter, the present invention will be described in detail by way of Synthesis Examples, Examples and Comparative Examples, but the present invention is not limited to the following Examples.

Structures of the quenchers 1 to 13 made of an acetyl chloride salt compound used in the resist composition of the present invention are shown below. Quenches 1 to 13 synthesize an acetylated compound giving the following cations according to the method described in International Publication No. 2015/111640, and then reacting the above-mentioned biguanide compound with a carboxylic acid giving the following anion, sulfonimide , Nitric acid, hydrochloric acid or hydrobromic acid.

[Synthesis Examples] Synthesis of polymer compounds (Polymers 1 to 6)

The respective monomers were combined, copolymerized under a tetrahydrofuran solvent, crystallized in methanol, washed with hexane, and then isolated and dried to obtain a polymer compound (polymer 1 to 6 ). The composition of the obtained polymer compound was confirmed by ¹ H-NMR and Mw and the degree of dispersion (Mw / Mn) by gel permeation chromatography (solvent: tetrahydrofuran (THF), standard: polystyrene).

[Examples, Comparative Examples]

A solution prepared by dissolving the respective components in the compositions shown in Tables 1 and 2 was filtered through a filter having a size of 0.2 mu m in a solvent prepared by dissolving 100 ppm of a surfactant FC-4430 manufactured by Sumitomo 3M Co., Ltd. as a surfactant, Type resist material and a negative resist material were prepared.

In Table 1 and Table 2, the respective compositions are as follows.

Polymers 1 to 6 (see the above formula)

Organic solvents: PGMEA (propylene glycol monomethyl ether acetate)

GBL (gamma -butyrolactone)

CyH (cyclohexanone)

CyP (cyclopentanone)

PGME (propylene glycol monomethyl ether)

Acid generator: PAG 1 to 3 (see the following structural formula)

Comparative quenchers 1 to 5 (see the following structural formula)

Water repellent polymer 1 (see the following structural formula)

[ArF liquid immersion exposure evaluation]

[Examples 1-1 to 1-14, Comparative Examples 1-1 to 1-5]

A resist material shown in Table 1 was spin-coated on a silicon wafer with a spin-on-carbon film ODL-102 (carbon content 80% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. as a film with a thickness of 200 nm, -A940 (silicon content: 43 mass%) was spin-coated on a substrate for a tri-layer process having a film thickness of 35 nm and baked at 100 DEG C for 60 seconds using a hot plate to obtain a resist film having a thickness of 80 nm. Using the ArF excimer laser scanner (NSR-S610C manufactured by Nikon Corporation, NA 1.30, σ 0.98 / 0.78, 35 degrees cross pole illumination, azimuthally polarized illumination, 6% halftone phase shift mask) Exposed using a mask having dimensions of 60 nm line and 200 nm pitch and subjected to PEB at a temperature shown in Table 1 for 60 seconds and successively developed with n-butyl acetate for 30 seconds to form a resist film having dimensions of 60 nm and 200 nm Thereby forming a negative pattern of the pitch trench. Next, the above exposure and PEB were performed in the same manner. After the wafer was stored at 23 DEG C for 24 hours in a FOUP, the wafer was developed with n-butyl acetate for 30 seconds to form a negative pattern of the trench with a pitch of 200 nm. The dimensions of the trench pattern were measured with a Hitachi High-Technologies SEM (CG-4000) manufactured by Hitachi High-Technologies Corporation, and the trench pattern formed by standing for 24 hours after PEB, Was taken as the PPD dimension. The results are shown in Table 1.

[EB imaging evaluation]

[Examples 2-1 to 2-5, Comparative Examples 2-1 to 2-5]

The resist materials shown in Table 2 were spin-coated on a hexamethyldisilazane vapor-treated Si substrate and pre-baked at 110 DEG C for 60 seconds using a hot plate to prepare a resist film of 80 nm. In this, HL-800D manufactured by HITASEISAKUSHO Co., Ltd. was used to perform drawing in a vacuum chamber at an acceleration voltage of 50 kV. Immediately after imaging, the film was immediately subjected to PEB on a hot plate at 90 캜 for 60 seconds, and developed with an aqueous solution of 2.38% by mass of tetramethylammonium hydroxide for 30 seconds to obtain a pattern.

The following evaluation was made on the obtained resist pattern.

In the case of the positive type resist film, the minimum trench size at the exposure amount for resolving the 120 nm trench to the dimensions was defined as the resolution. In the case of the negative type resist film, the resolution of the minimum isolated line in the exposure amount for resolving the isolated line of 120 nm to the dimensions was determined as the resolution. Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-3 and 2-5 are positive resist materials, and Example 2-5 and Comparative Example 2-4 are negative resist materials.

The results are shown in Table 2.

From the results shown in Tables 1 and 2, it was found that the resist material containing an asymmetric salt compound of the present invention had excellent dimensional stability in PPD and sufficient resolution and LWR.

Claims (14)

A resist material comprising a base polymer and an asymmetric salt compound represented by the following formula (A).

Wherein R ¹ to R ⁸ each independently represent a hydrogen atom, a straight-chain, branched or cyclic alkyl group having 1 to 24 carbon atoms, a linear, branched or cyclic alkenyl group having 2 to 24 carbon atoms, An aryl group, an ether group, a sulfide group, a sulfoxide group, a carbonate group, a carbamate group, a sulfone group, an amino group R ¹ and R ² , R ² and R ³ , R ³ and R ⁴ , R ⁵ and R ⁶ , R ⁶ and R ⁷ , R ⁶ , R ⁷ and R ^{8 are the same as or different from each other} , Or R ⁷ and R ⁸ may combine to form a ring, and the ring may contain an ether bond. A ^- is a cation selected from the group consisting of hydroxide ion, chloride ion, bromide ion, iodide ion, nitrate ion, nitrite ion, chlorate ion, chlorite ion, perchlorate ion, hydrogen carbonate ion, hydrogenphosphate ion, A hydrogen ion, a cyanide ion, an iodic acid ion, or an anion represented by the following formula (M-1) or (M-2).

(Wherein R ⁹ represents a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms, a linear, branched or cyclic alkenyl group having 2 to 30 carbon atoms, a linear, An aralkyl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an aromatic or aliphatic heterocyclic containing group having 3 to 20 carbon atoms. Among these groups, an ester group, an ether group, a sulfide group R ⁹ is a group represented by the following formula (A) -1 (wherein R ¹ is a hydrogen atom, a halogen atom,

(Wherein Ar is an aromatic group having 6 to 16 carbon atoms; R ¹² and R ¹³ are each independently a hydrogen atom, a hydroxyl group, an alkoxy group, a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, Lt; / RTI &gt;
Quot; is not included. R ¹⁰ is a fluorine atom, a linear, branched or cyclic fluorinated alkyl group having 1 to 10 carbon atoms, or a fluorinated phenyl group, and may contain a hydroxyl group, an ether group, an ester group or an alkoxy group. R ¹¹ is a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, a linear, branched or cyclic alkenyl group having 2 to 10 carbon atoms, a straight or branched alkynyl group having 2 to 10 carbon atoms, Or an aryl group having 6 to 10 carbon atoms, which may contain a hydroxyl group, an ether group, an ester group or an alkoxy group) The resist material according to claim 1, further comprising an acid generator which generates a sulfonic acid, a sulfonimide or a sulfonimide. The resist material according to claim 1, further comprising an organic solvent. The resist material according to claim 1, wherein the base polymer comprises a repeating unit represented by the following formula (a1) or a repeating unit represented by the following formula (a2).

Wherein R ³¹ and R ³³ are each independently a hydrogen atom or a methyl group, R ³² and R ³⁴ are each independently an acid labile group, X is a single bond, an ester group, a phenylene group, a naphthylene group, And Y is a single bond or an ester group.) The resist material according to claim 4, further comprising a dissolution inhibitor. The resist material according to claim 4, which is a chemically amplified positive resist material. The resist material of claim 1, wherein the base polymer does not comprise an acid labile group. The resist material according to claim 7, further comprising a crosslinking agent. 8. The resist composition according to claim 7, wherein the resist composition is a chemically amplified negative resist composition. The resist material according to claim 1, wherein the base polymer further comprises at least one repeating unit selected from repeating units represented by the following formulas (f1) to (f3).

(Wherein R ⁵¹ , R ⁵⁵ and R ⁵⁹ are each independently a hydrogen atom or a methyl group, R ⁵² is a single bond, a phenylene group, -OR ⁶³ - or -C (= O) -Y ¹ -R ⁶³ - , Y ¹ is -O- or -NH-, and R ⁶³ is a linear, branched or cyclic, alkylene or alkenylene group having 1 to 6 carbon atoms which may contain a carbonyl group, an ester group, an ether group or a hydroxy group a, or a phenylene ^{group. R 53, R 54, R} 56, R 57, R 58, R 60, R 61 and R ⁶² are each independently a carbonyl group, a straight good having 1 to 12 carbon atoms optionally containing an ester group or ether chain, branched or cyclic alkyl group, or aryl group having a carbon number of 6-12, an aralkyl group, or mercapto group of a carbon number of 7~20. a ¹ represents a single ^{bond, -A 0 -C (= O)} -O- , -A ⁰ -O- or -A ⁰ -OC (= O) -, and A ⁰ represents a straight, branched or cyclic alkyl group having 1 to 12 carbon atoms which may contain a carbonyl group, an ester group or an ether group .. It is the alkylene group A ² is a hydrogen atom or a trifluoromethyl group Z ¹ is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenyl group, -OR ⁶⁴ -, or -C (= O) -Z ² -R ⁶⁴ -, Z ² is -O- or -NH-, and R ⁶⁴ is a straight, branched or cyclic, straight, branched or cyclic C 1-6 carbon atom which may contain a carbonyl group, an ester group, an ether group or a hydroxy group, an alkyl group or an alkenylene group, or a phenylene group, a fluorinated phenyl substituted with a methyl group as a group, or a trifluorophenyl group M ^-.. represents a non-nucleophilic counter ion is f1, f2 and f3 are 0≤f1≤0.5, 0? F2? 0.5, 0? F3? 0.5 and 0 <f1 + f2 + f3? 0.5. The resist material according to claim 1, further comprising a surfactant. A pattern forming method comprising: a step of applying the resist material of claim 1 on a substrate; a step of exposing the substrate to a high energy beam after the heat treatment; and a step of developing by using a developer. The pattern forming method according to claim 12, wherein the high energy ray is an ArF excimer laser having a wavelength of 193 nm or a KrF excimer laser having a wavelength of 248 nm. 13. The pattern forming method according to claim 12, wherein the high energy ray is an electron beam or an extreme ultraviolet ray having a wavelength of 3 to 15 nm.