JP2017182033A - Resist material and pattern forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resist material that reduces acid diffusion, has higher resolution than that of conventional resist materials, shows small edge roughness (LER, LWR), and gives an excellent pattern shape, and a pattern forming method using the resist material.SOLUTION: A resist material comprises a base resin comprising a polymer that comprises a repeating unit represented by formula (a) and a repeating unit comprising a group with its polarity changed by acid, and has a weight average molecular weight of 1,000-500,000.SELECTED DRAWING: None

Description

  The present invention relates to a resist material and a pattern forming method using the resist material.

  With the high integration and high speed of LSI, pattern rule miniaturization is progressing rapidly. In particular, the expansion of the flash memory market and the increase in storage capacity are leading to miniaturization. As state-of-the-art miniaturization technology, mass production of 65 nm node devices by ArF lithography has been performed, and preparation for mass production of 45 nm nodes by next generation ArF immersion lithography is in progress. The next generation 32nm node includes immersion lithography with ultra-high NA lens combining liquid with higher refractive index than water, high refractive index lens and high refractive index resist film, extreme ultraviolet (EUV) lithography with wavelength of 13.5nm. ArF lithography double exposure (double patterning lithography) and the like are candidates and are being studied.

  High energy rays with very short wavelengths, such as electron beams (EB) and X-rays, are hardly absorbed by the hydrocarbons used in the resist material, and are therefore mainly based on polyhydroxystyrene based on hydrocarbons. Resist materials are being considered.

  As a mask manufacturing exposure apparatus, an EB exposure apparatus has been used in place of a laser beam exposure apparatus in order to increase the accuracy of the line width. Furthermore, since further miniaturization is possible by increasing the acceleration voltage of the electron gun, 10 kV to 30 kV, and recently 50 kV is the mainstream, and studies of 100 kV are also underway.

  Here, as the acceleration voltage increases, lowering the sensitivity of the resist film has become a problem. When the acceleration voltage is increased, the influence of forward scattering in the resist film is reduced, so that the contrast of electron drawing energy is improved and the resolution and dimensional controllability are improved. Since it passes, the sensitivity of the resist film decreases. Since the mask exposure machine exposes with one stroke of direct drawing, a decrease in sensitivity of the resist film leads to a decrease in productivity, which is not preferable. Chemically amplified resist materials are being studied in order to meet the demand for higher sensitivity.

  As miniaturization progresses, image blur due to acid diffusion has become a problem. In order to ensure the resolution in a fine pattern having a size size of 45 nm or less, it is proposed that not only the conventionally proposed improvement in dissolution contrast but also the control of acid diffusion is important (Non-Patent Document). 1). However, chemically amplified resist materials have increased sensitivity and contrast due to acid diffusion. Therefore, if the post-exposure bake (PEB) temperature and time are shortened to minimize acid diffusion, the sensitivity and contrast are significantly reduced. .

  The relationship of sensitivity, resolution and edge roughness triangle trade-off is shown. Here, in order to improve the resolution, it is necessary to suppress acid diffusion, but when the acid diffusion distance is shortened, the sensitivity is lowered.

  It is effective to suppress acid diffusion by adding an acid generator that generates a bulky acid. Therefore, it has been proposed that a repeating unit derived from an onium salt containing a polymerizable unsaturated bond is included in the polymer as an acid generator. Patent Document 1 proposes a sulfonium salt or an iodonium salt containing a polymerizable unsaturated bond that generates a specific sulfonic acid. Patent Document 2 proposes a sulfonium salt in which a sulfonic acid is directly bonded to the main chain.

  Studies are also underway to suppress acid diffusion using techniques other than bulky acid generators. Patent Documents 3 to 8 describe adhesive groups containing nitrogen atoms. The presence of an electron pair of nitrogen atoms is effective for controlling acid diffusion. However, the nitrogen atom may not only prevent acid diffusion but also suppress acid catalyzed reactions. In this case, the deprotection reaction does not proceed or even if it proceeds, the contrast is lowered. Problems arise.

JP 2006-045311 A JP 2006-178317 A JP 2011-203656 A International Publication No. 2011/024953 International Publication No. 2012/043102 International Publication No. 2013/129342 JP 2012-62371 A JP 2012-197382 A

SPIE Vol. 6520 65203L-1 (2007)

  The present invention has been made in view of the above circumstances, a resist material that reduces acid diffusion, has higher resolution than conventional resist materials, has low edge roughness (LER, LWR), and provides a good pattern shape, and An object is to provide a pattern forming method using a resist material.

  As a result of intensive investigations to obtain a resist material having high sensitivity, high resolution, and low edge roughness, which has been recently demanded, the present inventors have developed a polymer containing a repeating unit containing a succinimide structure as a resist material, particularly It has been found that it is extremely effective when used as a base resin for chemically amplified resist materials.

  Furthermore, in order to suppress the acid diffusion and improve the dissolution contrast, the present inventors use a resist material containing a polymer containing a predetermined repeating unit containing a succinimide structure and a repeating unit containing a group whose polarity is changed by an acid, Especially when used as a base resin for chemically amplified resist materials, it has high sensitivity, very high alkali dissolution rate contrast before and after exposure, high effect of suppressing acid diffusion, high resolution, and pattern shape after exposure. It has been found that a resist material, particularly a chemically amplified resist material, having a good edge roughness, particularly suitable for VLSI manufacturing or for forming a fine pattern of a photomask can be obtained.

  In particular, the resist material of the present invention can increase the decomposition efficiency of the acid generator, so it has high sensitivity, high effect of suppressing acid diffusion, high resolution, small edge roughness, and process adaptability. The pattern shape after exposure is good. Therefore, since it has these excellent characteristics, it is extremely practical and is very effective as a resist material for VLSI and a mask pattern forming material.

（式中、Ｒ¹は、水素原子又はメチル基を表す。Ｒ²は、水素原子、炭素数１〜８の直鎖状、分岐状若しくは環状のアルキル基、炭素数２〜６の直鎖状、分岐状若しくは環状のアシル基、又は炭素数２〜６の直鎖状、分岐状若しくは環状のアルコキシカルボニル基を表す。Ｘ¹は、単結合、フェニレン基、ナフチレン基、又はエステル基、エーテル基若しくはラクトン環を含む炭素数１〜１２の連結基を表す。ａは、０＜ａ＜１.０を満たす正数を表す。）
２．酸による極性変化が、脱離反応によるものである１のレジスト材料。
３．酸によって極性が変化する基を含む繰り返し単位が、酸不安定基で置換された、カルボキシル基又はフェノール性ヒドロキシ基を含むものである１又は２のレジスト材料。
４．酸によって極性が変化する基を含む繰り返し単位が、下記式（ｂ１）又は（ｂ２）で表されるものである３のレジスト材料。

（式中、Ｒ³及びＲ⁵は、それぞれ独立に、水素原子又はメチル基を表す。Ｒ⁴及びＲ⁸は、それぞれ独立に、酸不安定基を表す。Ｒ⁶は、単結合、又は炭素数１〜６の直鎖状若しくは分岐状のアルキレン基を表す。Ｒ⁷は、水素原子、フッ素原子、トリフルオロメチル基、シアノ基、炭素数１〜６の直鎖状、分岐状若しくは環状の、アルキル基若しくはアルコキシ基、又は炭素数２〜７の直鎖状、分岐状若しくは環状の、アシル基、アシロキシ基若しくはアルコキシカルボニル基を表す。ｐは、１又は２を表す。ｑは、０〜４の整数を表す。Ｙ¹は、単結合、フェニレン基、ナフチレン基、又はエステル基、エーテル基若しくはラクトン環を含む炭素数１〜１２の連結基を表す。Ｙ²は、単結合、−Ｃ(＝Ｏ)−Ｏ−、又は−Ｃ(＝Ｏ)−ＮＨ−を表す。ｂ１及びｂ２は、０≦ｂ１＜１.０、０≦ｂ２＜１.０、及び０＜ｂ１＋ｂ２＜１.０を満たす正数を表す。）
５．酸によって極性が変化する基を含む繰り返し単位が、酸による脱水反応によって親水性から疎水性に変化する繰り返し単位である１又は２のレジスト材料。
６．酸によって極性が変化する基を含む繰り返し単位が、下記式で表されるモノマーに由来するものである５のレジスト材料。

（式中、Ｒ⁹は、水素原子又はメチル基を表す。）
７．前記ポリマーが、更に、ヒドロキシ基、カルボキシル基、ラクトン環、カーボネート基、チオカーボネート基、カルボニル基、環状アセタール基、エーテル基、エステル基、スルホン酸エステル基、シアノ基、アミド基、及び−Ｏ−Ｃ(＝Ｏ)−Ｇ−（Ｇは、−Ｓ−又は−ＮＨ−である。）から選ばれる密着性基を含む繰り返し単位を含む１〜６のいずれかのレジスト材料。
８．前記ポリマーが、更に、下記式（ｄ１）〜（ｄ３）から選ばれる繰り返し単位を少なくとも１つ含む１〜７のいずれかのレジスト材料。

（式中、Ｒ²⁰、Ｒ²⁴及びＲ²⁸は、それぞれ独立に、水素原子又はメチル基を表す。Ｒ²¹は、単結合、フェニレン基、−Ｏ−Ｒ^A−、又は−Ｃ(＝Ｏ)−Ｙ⁰−Ｒ^A−を表し、Ｙ⁰は、−Ｏ−又は−ＮＨ−を表し、Ｒ^Aは、カルボニル基、エステル基、エーテル基若しくはヒドロキシ基を含んでいてもよい、炭素数１〜６の直鎖状、分岐状若しくは環状のアルキレン基若しくは炭素数２〜６の直鎖状、分岐状若しくは環状のアルケニレン基、又はフェニレン基を表す。Ｒ²²、Ｒ²³、Ｒ²⁵、Ｒ²⁶、Ｒ²⁷、Ｒ²⁹、Ｒ³⁰及びＲ³¹は、それぞれ独立に、カルボニル基、エステル基若しくはエーテル基、ヒドロキシ基を含んでいてもよい炭素数１〜１２の直鎖状、分岐状若しくは環状のアルキル基、又は炭素数６〜１２のアリール基、炭素数７〜２０のアラルキル基若しくはメルカプトフェニル基を表す。Ｚ¹は、単結合、若しくはエーテル基、エステル基若しくはラクトン環を含んでいてもよい炭素数１〜１２の直鎖状、分岐状若しくは環状のアルキレン基、若しくは炭素数２〜１２の直鎖状、分岐状若しくは環状のアルケニレン基、又は炭素数６〜１０のアリーレン基を表す。Ｚ²は、単結合、メチレン基、エチレン基、フェニレン基、フッ素化されたフェニレン基、−Ｏ−Ｒ³²−、又は−Ｃ(＝Ｏ)−Ｚ³−Ｒ³²−を表し、Ｚ³は、−Ｏ−又は−ＮＨ−を表し、Ｒ³²は、カルボニル基、エステル基、エーテル基若しくはヒドロキシ基を含んでいてもよい炭素数１〜１２の直鎖状、分岐状若しくは環状の、アルキレン基若しくはアルケニレン基、又はフェニレン基を表す。Ｍ^-は、非求核性対向イオンを表す。ｄ１〜ｄ３は、０≦ｄ１≦０.５、０≦ｄ２≦０.５、０≦ｄ３≦０.５、及び０＜ｄ１＋ｄ２＋ｄ３≦０.５を満たす正数を表す。）
９．更に、酸発生剤及び有機溶剤を含む１〜８のいずれかのレジスト材料。
１０．更に、塩基性化合物及び／又は界面活性剤を含む１〜９のいずれかのレジスト材料。
１１．１〜１０のいずれかのレジスト材料を基板上に塗布する工程と、加熱処理後、高エネルギー線で露光する工程と、現像液を用いて現像する工程とを含むパターン形成方法。
１２．前記高エネルギー線が、ｉ線、ＫｒＦエキシマレーザー、ＡｒＦエキシマレーザー、ＥＢ、又は波長３〜１５ｎｍの範囲のＥＵＶである１１のパターン形成方法。 That is, the present invention provides the following resist material and pattern forming method.
1. A resist material comprising a base resin comprising a repeating unit represented by the following formula (a) and a repeating unit containing a group whose polarity is changed by an acid and having a weight average molecular weight of 1,000 to 500,000 .

(In the formula, R ¹ represents a hydrogen atom or a methyl group. R ² represents a hydrogen atom, a straight chain having 1 to 8 carbon atoms, a branched or cyclic alkyl group, or a straight chain having 2 to 6 carbon atoms. Represents a branched or cyclic acyl group, or a linear, branched or cyclic alkoxycarbonyl group having 2 to 6 carbon atoms, and X ¹ represents a single bond, a phenylene group, a naphthylene group, an ester group or an ether group. Alternatively, it represents a linking group having 1 to 12 carbon atoms including a lactone ring, and a represents a positive number satisfying 0 <a <1.0.
2. 1. A resist material, wherein the polarity change due to an acid is due to an elimination reaction.
3. The resist material according to 1 or 2, wherein the repeating unit including a group whose polarity is changed by an acid includes a carboxyl group or a phenolic hydroxy group substituted with an acid labile group.
4). 3. The resist material according to 3, wherein the repeating unit containing a group whose polarity is changed by an acid is represented by the following formula (b1) or (b2).

(In the formula, R ³ and R ⁵ each independently represent a hydrogen atom or a methyl group. R ⁴ and R ⁸ each independently represent an acid labile group. R ⁶ represents a single bond or carbon. Represents a linear or branched alkylene group having 1 to 6. R ⁷ represents a hydrogen atom, a fluorine atom, a trifluoromethyl group, a cyano group, a linear, branched or cyclic group having 1 to 6 carbon atoms. , An alkyl group or an alkoxy group, or a linear, branched or cyclic acyl group, acyloxy group or alkoxycarbonyl group having 2 to 7 carbon atoms, p represents 1 or 2, and q represents 0 to 0. Represents an integer of 4. Y ¹ represents a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms including an ester group, an ether group, or a lactone ring, Y ² represents a single bond, —C (═O) —O— or —C (═O) —NH— .b1 and b2 represent positive numbers satisfying 0 ≦ b1 <1.0,0 ≦ b2 <1.0, and 0 <b1 + b2 <1.0.)
5. The resist material according to 1 or 2, wherein the repeating unit containing a group whose polarity is changed by an acid is a repeating unit which changes from hydrophilic to hydrophobic by a dehydration reaction with an acid.
6). 5. The resist material according to 5, wherein the repeating unit containing a group whose polarity is changed by an acid is derived from a monomer represented by the following formula.

(Wherein R ⁹ represents a hydrogen atom or a methyl group.)
7). The polymer further includes a hydroxy group, a carboxyl group, a lactone ring, a carbonate group, a thiocarbonate group, a carbonyl group, a cyclic acetal group, an ether group, an ester group, a sulfonic acid ester group, a cyano group, an amide group, and —O—. The resist material according to any one of 1 to 6, comprising a repeating unit containing an adhesive group selected from C (═O) —G— (G is —S— or —NH—).
8). The resist material according to any one of 1 to 7, wherein the polymer further contains at least one repeating unit selected from the following formulas (d1) to (d3).

(In the formula, R ²⁰ , R ²⁴ and R ²⁸ each independently represent a hydrogen atom or a methyl group. R ²¹ represents a single bond, a phenylene group, —O—R ^A —, or —C (═O). —Y ⁰ —R ^A —, Y ⁰ represents —O— or —NH—, and R ^A may contain a carbonyl group, an ester group, an ether group or a hydroxy group. 6 represents a linear, branched or cyclic alkylene group, a linear, branched or cyclic alkenylene group having 2 to 6 carbon atoms, or a phenylene group, R ²² , R ²³ , R ²⁵ , R ²⁶ , R ²⁷ , R ²⁹ , R ³⁰ and R ³¹ are each independently a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms which may contain a carbonyl group, an ester group or an ether group, or a hydroxy group. Group, an aryl group having 6 to 12 carbon atoms, or an aryl group having 7 to 20 carbon atoms. Represents a aralkyl group or a mercaptophenyl group, and Z ¹ represents a single bond, an ether group, an ester group or a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms which may contain a lactone ring, or A linear, branched or cyclic alkenylene group having 2 to 12 carbon atoms, or an arylene group having 6 to 10 carbon atoms, Z ² represents a single bond, a methylene group, an ethylene group, a phenylene group, or a fluorinated group. Represents a phenylene group, —O—R ³² —, or —C (═O) —Z ³ —R ³² —, Z ³ represents —O— or —NH—, and R ³² represents a carbonyl group or an ester group. , .M of an ether group or hydroxy group of which may contain carbon atoms of 1 to 12 linear, branched or cyclic, alkylene or alkenylene group, or a phenylene group ^- is a non-nucleophilic counter .d1~d3 representing the ON represents a positive number satisfying 0 ≦ d1 ≦ 0.5,0 ≦ d2 ≦ 0.5,0 ≦ d3 ≦ 0.5, and 0 <d1 + d2 + d3 ≦ 0.5.)
9. Furthermore, the resist material in any one of 1-8 containing an acid generator and an organic solvent.
10. Furthermore, the resist material in any one of 1-9 containing a basic compound and / or surfactant.
11. A pattern forming method including a step of applying a resist material of any one of 11.1 to 10 on a substrate, a step of exposing to high energy rays after heat treatment, and a step of developing using a developer.
12 11. The pattern forming method according to 11, wherein the high energy ray is i-line, KrF excimer laser, ArF excimer laser, EB, or EUV having a wavelength in the range of 3 to 15 nm.

  The resist material of the present invention is highly effective in suppressing acid diffusion, has high resolution, and has good pattern shape and edge roughness after exposure. Therefore, it is particularly suitable as a material for forming a fine pattern of a photomask for VLSI manufacturing or EB drawing, or as a pattern forming material for i-line, KrF excimer laser, ArF excimer laser, EB or EUV exposure.

  The resist material of the present invention, particularly a chemically amplified resist material, can be used not only for lithography in semiconductor circuit formation, but also for mask circuit pattern formation, micromachine, and thin film magnetic head circuit formation.

[Resist material]
[Base resin]
The resist material of the present invention comprises a polymer (hereinafter referred to as polymer A) comprising a repeating unit represented by the following formula (a) (hereinafter also referred to as repeating unit a) and a repeating unit containing a group whose polarity is changed by an acid. Also referred to as a base resin.

In the formula, R ¹ represents a hydrogen atom or a methyl group. R ² is a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms, a linear, branched or cyclic acyl group having 2 to 6 carbon atoms, or 2 to 6 carbon atoms. A linear, branched or cyclic alkoxycarbonyl group is represented. X ¹ represents a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms including an ester group, an ether group, or a lactone ring. a represents a positive number satisfying 0 <a <1.0.

（式中、Ｒ¹、Ｒ²及びＸ¹は、前記と同じ。） Examples of the monomer Ma that gives the repeating unit a include those represented by the following formula (Ma).

(In the formula, R ¹ , R ² and X ¹ are the same as above.)

［式中、Ｒ¹、Ｒ²及びＸ¹は、前記と同じ。Ｘ²は、水素原子、塩素原子、臭素原子等のハロゲン原子、又は下記式（ａ３）で表される基を表す。

（式中、Ｒ¹及びＸ¹は、前記と同じ。破線は、結合手を表す。）］ The monomer Ma can be synthesized, for example, by a reaction between a compound represented by the following formula (a1) and a compound represented by the following formula (a2).

[Wherein R ¹ , R ² and X ¹ are the same as described above. X ² represents a halogen atom such as a hydrogen atom, a chlorine atom or a bromine atom, or a group represented by the following formula (a3).

(In the formula, R ¹ and X ¹ are the same as above. The broken line represents a bond.)]

Examples of the monomer Ma include, but are not limited to, those shown below. In the following formula, R ¹ is the same as described above.

  The repeating unit a includes a succinimide structure. Amide groups and carbamate groups containing both nitrogen and oxygen atoms have the disadvantage of suppressing acid diffusion and suppressing deprotection reaction, but the succinimide structure has two carbonyl groups around the nitrogen atom. Therefore, the basicity of the nitrogen atom is low and the acid-catalyzed deprotection reaction is not inhibited. Nevertheless, the effect of suppressing acid diffusion by the unpaired electrons of the nitrogen atom is high. Adhesion can be ensured by the three carbonyl groups, and acid diffusion can be suppressed by unpaired electrons of the nitrogen atom, which can reduce pattern collapse and edge roughness (LWR).

Examples of the repeating unit containing a group whose polarity is changed by the acid (hereinafter also referred to as repeating unit b) include a repeating unit containing a carboxyl group or a phenolic hydroxy group substituted with an acid labile group. As such a repeating unit, a repeating unit represented by the following formula (b1) (hereinafter also referred to as repeating unit b1) or a repeating unit represented by the following formula (b2) (hereinafter also referred to as repeating unit b2). .) Is preferred. When the repeating units b1 and / or b2 are used, the resist material of the present invention can be used as a positive resist material that obtains a positive pattern by alkali development or a negative resist material that obtains a negative pattern by organic solvent development. .

In the formula, R ³ and R ⁵ each independently represents a hydrogen atom or a methyl group. R ⁴ and R ⁸ each independently represents an acid labile group. R ⁶ represents a single bond or a linear or branched alkylene group having 1 to 6 carbon atoms. R ⁷ is a hydrogen atom, a fluorine atom, a trifluoromethyl group, a cyano group, a linear, branched or cyclic alkyl group or alkoxy group having 1 to 6 carbon atoms, or a linear structure having 2 to 7 carbon atoms. Represents a branched or cyclic acyl group, an acyloxy group or an alkoxycarbonyl group. p represents 1 or 2. q represents an integer of 0 to 4. Y ¹ represents a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms including an ester group, an ether group, or a lactone ring. Y ² represents a single bond, —C (═O) —O—, or —C (═O) —NH—. b1 and b2 represent positive numbers that satisfy 0 ≦ b1 <1.0, 0 ≦ b2 <1.0, and 0 <b1 + b2 <1.0.

（式中、Ｒ³〜Ｒ⁸、Ｙ¹、Ｙ²、ｐ及びｑは、前記と同じ。） Examples of the monomer Mb1 that gives the repeating unit b1 include those represented by the following formula (Mb1). Examples of the monomer Mb2 that gives the repeating unit b2 include those represented by the following formula (Mb2).

(Wherein R ^{3 to} R ⁸ , Y ¹ , Y ² , p and q are the same as above).

The linking group having 1 to 12 carbon atoms containing a lactone ring represented by Y ^1, and the like those shown below.

Examples of the monomer Mb1 include, but are not limited to, those shown below. In the following formulae, R ³ and R ⁴ are the same as described above.

Examples of the monomer Mb2 include, but are not limited to, those shown below. In the following formula, R ⁵ and R ⁸ are the same as described above.

The acid labile groups represented by R ⁴ in the formula (Mb1) and R ⁸ in the formula (Mb2) are variously selected and may be the same or different. Acid labile groups described in JP2013-83821A can be used.

Typically, what is shown by a following formula is mentioned.

In the formula, R ⁵¹ and R ⁵⁴ each independently represent a monovalent hydrocarbon group such as a linear, branched or cyclic alkyl group having 1 to 40 carbon atoms, particularly 1 to 20 carbon atoms, oxygen, sulfur, Hetero atoms such as nitrogen and fluorine may be contained. R ⁵² and R ⁵³ each independently represent a hydrogen atom or a monovalent hydrocarbon group such as a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, such as oxygen, sulfur, nitrogen, fluorine, etc. Of heteroatoms. a5 represents an integer of 0 to 10, particularly 1 to 5. R ⁵² and R ⁵³ , R ⁵² and R ⁵⁴ , or R ⁵³ and R ⁵⁴ are bonded to each other and together with the carbon atom or carbon atom and oxygen atom to which they are bonded, the number of carbon atoms is 3 to 20, preferably 4 to You may form 16 rings, especially an alicyclic ring.

R ⁵⁵ , R ⁵⁶ and R ⁵⁷ each independently represent a monovalent hydrocarbon group such as a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, such as oxygen, sulfur, nitrogen, fluorine, etc. Hetero atoms may be included. R ⁵⁵ and R ⁵⁶ , R ⁵⁵ and R ⁵⁷ , or R ⁵⁶ and R ⁵⁷ , together with the carbon atom to which they are bonded, have 3 to 20 carbon atoms, preferably 4 to 16 carbon atoms, A ring may be formed.

  As the repeating unit b, a repeating unit that changes from hydrophilic to hydrophobic by a dehydration reaction with an acid (hereinafter also referred to as a repeating unit b3) may be used. When the repeating unit b3 is used, the resist material of the present invention can be used as a negative resist material for obtaining a negative pattern by alkali development.

Examples of the monomer that gives the repeating unit b3 include, but are not limited to, those shown below. In the following formulae, R ⁹ represents a hydrogen atom or a methyl group.

  The polymer A further includes a hydroxy group, a carboxyl group, a lactone ring, a carbonate group, a thiocarbonate group, a carbonyl group, a cyclic acetal group, an ether group, an ester group, a sulfonic acid ester group, a cyano group, an amide group, and —O—. A repeating unit containing an adhesive group selected from C (═O) —G— (G is —S— or —NH—) (hereinafter also referred to as a repeating unit c) may be included. Examples of the monomer that gives the repeating unit c include, but are not limited to, those shown below.

  In the case of a monomer containing a hydroxy group, the hydroxy group may be replaced with an acetal group that can be easily deprotected with an acid such as an ethoxyethoxy group at the time of polymerization, and then deprotected with a weak acid and water after the polymerization, or an acetyl group, Substitution with a formyl group, pivaloyl group or the like, and alkali hydrolysis may be performed after polymerization.

The polymer A may further include a repeating unit derived from a sulfonium salt represented by the following formulas (d1) to (d3) (hereinafter also referred to as repeating units d1 to d3, respectively).

In the formula, R ²⁰ , R ²⁴ and R ²⁸ each independently represent a hydrogen atom or a methyl group. R ²¹ represents a single bond, a phenylene group, —O—R ^A —, or —C (═O) —Y ⁰ —R ^A —, Y ⁰ represents —O— or —NH—, R ^A Is a linear, branched or cyclic alkylene group having 1 to 6 carbon atoms or a linear or branched chain having 2 to 6 carbon atoms, which may contain a carbonyl group, an ester group, an ether group or a hydroxy group. Or it represents a cyclic alkenylene group or a phenylene group. R ²² , R ²³ , R ²⁵ , R ²⁶ , R ²⁷ , R ²⁹ , R ³⁰ and R ³¹ each independently have 1 to 1 carbon atoms which may contain a carbonyl group, an ester group or an ether group, or a hydroxy group. 12 represents a linear, branched or cyclic alkyl group, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or a mercaptophenyl group. Z ¹ is a single bond, a C 1-12 linear, branched or cyclic alkylene group which may contain an ether group, an ester group or a lactone ring, or a C 2-12 linear Represents a branched or cyclic alkenylene group or an arylene group having 6 to 10 carbon atoms. Z ² represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, —O—R ³² —, or —C (═O) —Z ³ —R ³² —, and Z ³ represents Represents —O— or —NH—, and R ³² represents a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms which may contain a carbonyl group, an ester group, an ether group or a hydroxy group. Alternatively, it represents an alkenylene group or a phenylene group. M ⁻ represents a non-nucleophilic counter ion. d1 to d3 represent positive numbers that satisfy 0 ≦ d1 ≦ 0.5, 0 ≦ d2 ≦ 0.5, 0 ≦ d3 ≦ 0.5, and 0 <d1 + d2 + d3 ≦ 0.5.

  By binding an acid generator to the polymer main chain, acid diffusion can be reduced, and degradation of resolution due to blurring of acid diffusion can be prevented. Further, the edge roughness (LER, LWR) is improved by uniformly dispersing the acid generator.

Non-nucleophilic counter ions represented by M ⁻ include halide ions such as chloride ions and bromide ions; fluoroalkyl sulfonates such as triflate, 1,1,1-trifluoroethanesulfonate, and nonafluorobutanesulfonate; Aryl sulfonates such as tosylate, benzene sulfonate, 4-fluorobenzene sulfonate, 1,2,3,4,5-pentafluorobenzene sulfonate; alkyl sulfonates such as mesylate, butane sulfonate; bis (trifluoromethylsulfonyl) imide, bis ( And imido acids such as perfluoroethylsulfonyl) imide and bis (perfluorobutylsulfonyl) imide; and methide acids such as tris (trifluoromethylsulfonyl) methide and tris (perfluoroethylsulfonyl) methide.

Furthermore, as a non-nucleophilic counter ion represented by M ⁻ , a sulfonate having a fluoro substituted at the α-position represented by the following formula (K-1), α and β represented by the following formula (K-2) And sulfonates that are fluoro-substituted at the position.

In formula (K-1), R ⁴¹ represents a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an aryl having 6 to 20 carbon atoms. Represents an ether group, an ester group, a carbonyl group, a lactone ring, or a fluorine atom.

In formula (K-2), ^R42 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 2 to 30 carbon atoms. Represents an alkenyl group having 2 to 20 carbon atoms, 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. .

  In addition, when using the polymer containing the at least 1 repeating unit chosen from repeating unit d1-d3, the mixing | blending of the photo-acid generator mentioned later can be abbreviate | omitted.

The polymer A may further contain repeating units represented by the following formulas (e1) to (e5) (hereinafter also referred to as repeating units e1 to e5, respectively).

In the formula, each of R ^{110 to} R ¹¹⁴ is independently a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, or a carbon atom having 1 to 30 carbon atoms in which part or all of the hydrogen atoms bonded to the carbon atom are substituted with halogen atoms. An alkyl group, a hydroxy group, an alkoxy group having 1 to 30 carbon atoms, an acyl group having 2 to 30 carbon atoms, an alkoxycarbonyl group having 2 to 30 carbon atoms, an aryl group having 6 to 10 carbon atoms, a halogen atom, or 1, Represents a 1,1,3,3,3-hexafluoro-2-propanol group. X ⁰ represents a methylene group, an ether group, or a sulfide group.

  The polymer A may further contain a repeating unit f derived from styrene, vinyl naphthalene, vinyl anthracene, vinyl pyrene, methylene indane and the like.

  Examples of a method for synthesizing the polymer A include a method in which a desired monomer among the monomers that give the repeating units a to f is subjected to heat polymerization by adding a radical polymerization initiator in an organic solvent.

  Examples of the organic solvent used at the time of polymerization include toluene, benzene, tetrahydrofuran, diethyl ether, dioxane, cyclohexane, cyclopentane, methyl ethyl ketone, and γ-butyrolactone. As the polymerization initiator, 2,2′-azobisisobutyronitrile (AIBN), 2,2′-azobis (2,4-dimethylvaleronitrile), dimethyl-2,2-azobis (2-methylpropio) Nate), benzoyl peroxide, lauroyl peroxide and the like. The reaction temperature is preferably 50 to 80 ° C., and the reaction time is preferably 2 to 100 hours, more preferably 5 to 20 hours.

  When synthesizing a polymer containing repeating units derived from hydroxystyrene or hydroxyvinylnaphthalene, acetoxystyrene or acetoxyvinylnaphthalene is used instead of hydroxystyrene or hydroxyvinylnaphthalene. After polymerization, the acetoxy group is removed by alkali hydrolysis. It may be protected to a hydroxystyrene unit or a hydroxyvinylnaphthalene unit. Ammonia water, triethylamine, etc. can be used as the base during the alkali hydrolysis. Moreover, reaction temperature becomes like this. Preferably it is -20-100 degreeC, More preferably, it is 0-60 degreeC, Reaction time becomes like this. Preferably it is 0.2-100 hours, More preferably, it is 0.5-20 hours.

  In the polymer A, the ratio of the repeating units a and b is 0 <a <1.0, 0 <b <1.0, and 0.1 ≦ a + b ≦ 1.0. Here, when the repeating unit b is the repeating units b1 and b2, 0 <a <1.0, 0 ≦ b1 <1.0, 0 ≦ b2 <1.0, 0 <b1 + b2 <1.0, 0 0.1 ≦ a + b1 + b2 ≦ 1.0. When the repeating unit b is the repeating unit b3, 0 <a <1.0, 0 <b3 <1.0, and 0.1 ≦ a + b3 ≦ 1.0.

  The ratio of the repeating unit c is 0 ≦ c ≦ 0.9. When the repeating unit c is included, it is preferably 0 <c ≦ 0.9 and 0.2 ≦ a + b + c ≦ 1.0. Here, when the repeating unit b is the repeating units b1 and b2, more preferably 0.02 ≦ a ≦ 0.8, 0 ≦ b1 ≦ 0.8, 0 ≦ b2 ≦ 0.8, 0.1 ≦. b1 + b2 ≦ 0.8, 0.1 ≦ c ≦ 0.88, more preferably 0.05 ≦ a ≦ 0.75, 0 ≦ b1 ≦ 0.7, 0 ≦ b2 ≦ 0.7, 0.1 ≦ b1 + b2. ≦ 0.75, 0.15 ≦ c ≦ 0.85, particularly preferably 0.07 ≦ a ≦ 0.7, 0 ≦ b1 ≦ 0.65, 0 ≦ b2 ≦ 0.65, 0.1 ≦ b1 + b2 ≦ 0.7, 0.2 ≦ c ≦ 0.83. In this case, 0.2 ≦ a + b1 + b2 + c ≦ 1.0, more preferably 0.3 ≦ a + b1 + b2 + c ≦ 1.0, and still more preferably 0.4 ≦ a + b1 + b2 + c ≦ 1.0. When the repeating unit b is the repeating unit b3, more preferably 0.02 ≦ a ≦ 0.8, 0.1 ≦ b3 ≦ 0.8, 0.1 ≦ c ≦ 0.88, and still more preferably 0.8. 05 ≦ a ≦ 0.75, 0.1 ≦ b3 ≦ 0.75, 0.15 ≦ c ≦ 0.85, particularly preferably 0.07 ≦ a ≦ 0.7, 0.1 ≦ b3 ≦ 0.7 0.2 ≦ c ≦ 0.83. In this case, 0.2 ≦ a + b1 + b2 + c ≦ 1.0, more preferably 0.3 ≦ a + b3 + c ≦ 1.0, and still more preferably 0.4 ≦ a + b3 + c ≦ 1.0.

  The ratio of the repeating units d1 to d3 is 0 ≦ d1 ≦ 0.5, 0 ≦ d2 ≦ 0.5, 0 ≦ d3 ≦ 0.5, 0 ≦ d1 + d2 + d3 ≦ 0.5. If included, 0 <d1 + d2 + d3 ≦ 0.5. In this case, preferably 0 ≦ d1 ≦ 0.4, 0 ≦ d2 ≦ 0.4, 0 ≦ d3 ≦ 0.4, 0 <d1 + d2 + d3 ≦ 0.4, more preferably 0 ≦ d1 ≦ 0.3, 0 ≦ d2 ≦ 0.3, 0 ≦ d3 ≦ 0.3, 0 <d1 + d2 + d3 ≦ 0.3, more preferably 0 ≦ d1 ≦ 0.2, 0 ≦ d2 ≦ 0.2, 0 ≦ d3 ≦ 0.2, 0 <D1 + d2 + d3 ≦ 0.25. Further, 0.2 ≦ a + b1 + b2 + c + d1 + d2 + d3 ≦ 1.0, and particularly preferably 0.4 ≦ a + b1 + b2 + c + d1 + d2 + d3 ≦ 1.0.

  The ratio of the repeating units e1 to e5 is 0 ≦ e1 ≦ 0.5, 0 ≦ e2 ≦ 0.5, 0 ≦ e3 ≦ 0.5, 0 ≦ e4 ≦ 0.5, and 0 ≦ e5 ≦ 0.5. 0 ≦ e1 + e2 + e3 + e4 + e5 ≦ 0.5, but when repeating units e1 to e5 are included, 0 <e1 + e2 + e3 + e4 + e5 ≦ 0.5. In this case, preferably 0 ≦ e1 ≦ 0.4, 0 ≦ e2 ≦ 0.4, 0 ≦ e3 ≦ 0.4, 0 ≦ e4 ≦ 0.4, 0 ≦ e5 ≦ 0.4, 0 <e1 + e2 + e3 + e4 + e5 ≦ 0 .4, more preferably 0 ≦ e1 ≦ 0.3, 0 ≦ e2 ≦ 0.3, 0 ≦ e3 ≦ 0.3, 0 ≦ e4 ≦ 0.3, 0 ≦ e5 ≦ 0.3, 0 <e1 + e2 + e3 + e4 + e5 ≦ 0.3.

  The ratio of the repeating unit f is 0 ≦ f ≦ 0.5, preferably 0 ≦ f ≦ 0.4, and more preferably 0 ≦ f ≦ 0.3.

  It is preferable that a + b + c + d1 + d2 + d3 + e1 + e2 + e3 + e4 + e5 + f = 1.

  The polymer A has a weight average molecular weight (Mw) of 1,000 to 500,000, preferably 2,000 to 30,000. If Mw is 1,000 or more, the resist material is excellent in heat resistance, and if it is 500,000 or less, the alkali solubility is good, and there is no possibility that a trailing phenomenon will occur after pattern formation. In addition, Mw is a polystyrene conversion measured value by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent.

  In the polymer A, when the molecular weight distribution (Mw / Mn) of the multi-component copolymer is wide, there is a low molecular weight or high molecular weight polymer. Or get worse. Therefore, since the influence of molecular weight and molecular weight distribution tends to increase as the pattern rule becomes finer, the molecular weight distribution of the polymer A used is 1.0 in order to obtain a resist material suitably used for fine pattern dimensions. It is preferable that the dispersion is narrow, that is, -2.0, particularly 1.0-1.5.

  In the resist material of the present invention, the base resin includes one type of polymer A, a blend of two or more types of polymers having different composition ratios, molecular weight distributions, molecular weights, and the like, and a polymer that does not include polymer A and repeating unit a. B may be blended with B.

[Acid generator]
The resist material of the present invention may contain an acid generator in order to function as a chemically amplified resist material. Examples of the acid generator include compounds that generate an acid in response to actinic rays or radiation (photoacid generator).

  The photoacid generator may be any compound as long as it generates an acid upon irradiation with high energy rays. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, oxime-O-sulfonate type acid generators, and the like. Specific examples of such a photoacid generator include those described in paragraphs [0122] to [0142] of JP-A-2008-111103.

As a photo-acid generator, what is represented by following formula (1) can also be used conveniently.

In formula (1), R ¹⁰¹ , R ¹⁰² and R ¹⁰³ each independently represent a linear, branched or cyclic monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. . Further, any two or more 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).

In the formula (1A), R ^fa represents a fluorine atom or a linear, branched or cyclic monovalent hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom.

As the anion represented by the formula (1A), those represented by the following formula (1A ′) are preferable.

In 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 having 1 to 38 carbon atoms which may contain a hetero atom. As said hetero atom, an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, etc. are preferable, and an oxygen atom is more preferable. As the monovalent hydrocarbon group, those having 6 to 30 carbon atoms are particularly preferable from the viewpoint of obtaining high resolution in forming a fine pattern. Examples of the monovalent hydrocarbon group include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, t-butyl, pentyl, neopentyl, cyclopentyl, hexyl, and cyclohexyl. Group, 3-cyclohexenyl group, heptyl group, 2-ethylhexyl group, nonyl group, undecyl group, tridecyl group, pentadecyl group, heptadecyl group, 1-adamantyl group, 2-adamantyl group, 1-adamantylmethyl group, norbornyl group, Norbornylmethyl group, tricyclodecanyl group, tetracyclododecanyl group, tetracyclododecanylmethyl group, dicyclohexylmethyl group, icosanyl group, allyl group, benzyl group, diphenylmethyl group, tetrahydrofuryl group, methoxymethyl group, Ethoxymethyl group, methylthio Til group, acetamidomethyl group, trifluoroethyl group, (2-methoxyethoxy) methyl group, acetoxymethyl group, 2-carboxy-1-cyclohexyl group, 2-oxopropyl group, 4-oxo-1-adamantyl group, 3 -Oxocyclohexyl group etc. are mentioned. Further, some 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 between some of the carbon atoms of these groups. Hetero atom containing groups such as oxygen atom, sulfur atom and nitrogen atom may be interposed, and as a result, hydroxy group, cyano group, carbonyl group, ether group, ester group, sulfonate group, carbonate group, lactone ring , Sultone ring, carboxylic acid anhydride, haloalkyl group and the like.

  Regarding the synthesis of a sulfonium salt containing an anion represented by the formula (1A ′), JP2007-145797A, JP2008-106045A, JP2009-7327A, JP2009-258695A. It is detailed in etc. In addition, sulfonium salts described in JP2010-215608A, JP2012-41320A, JP2012-106986A, JP2012-153644A, and the like are also preferably used.

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

In formula (1B), R ^fb1 and R ^fb2 each independently represent a fluorine atom or a linear, branched or cyclic monovalent hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom. Represent. Examples of the monovalent hydrocarbon group include the same ones as mentioned in the description of the R ^105. R ^fb1 and R ^fb2 are preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. R ^fb1 and R ^fb2 may be bonded to each other to form a ring together with a group (—CF ₂ —SO ₂ —N ⁻ —SO ₂ —CF ₂ —) to which they are bonded. ^The group obtained by bonding ^fb1 and R ^fb2 to each other is preferably a fluorinated ethylene group or a fluorinated propylene group.

In formula (1C), R ^fc1 , R ^fc2 and R ^fc3 are each independently a linear, branched or cyclic monovalent carbon atom having 1 to 40 carbon atoms which may contain a fluorine atom or a hetero atom. Represents a hydrogen group. Examples of the monovalent hydrocarbon group include the same ones as mentioned in the description of the R ^105. R ^fc1 , R ^fc2 and R ^fc3 are preferably a fluorine atom or a linear 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 a group (—CF ₂ —SO ₂ —C ⁻ —SO ₂ —CF ₂ —) to which they are bonded. ^The group obtained by bonding ^fc1 and R ^fc2 to each other is preferably a fluorinated ethylene group or a fluorinated propylene group.

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

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

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

  Note that the photoacid generator containing an anion represented by the formula (1D) does not have fluorine at the α-position of the sulfo group, but has two trifluoromethyl groups at the β-position. Thus, it has sufficient acidity to cleave the acid labile group in the resist polymer. Therefore, it can be used as a photoacid generator.

Moreover, as a photo-acid generator, what is represented by following formula (2) can be used conveniently.

In formula (2), R ²⁰¹ and R ²⁰² each independently represents a linear, branched or cyclic monovalent hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom. R ²⁰³ represents a linear, branched or cyclic divalent hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom. Further, any two or more 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 single bond, an ether group, or a linear, branched or cyclic divalent hydrocarbon group having 1 to 20 carbon atoms which may contain 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. However, 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 methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group, n-pentyl group, t-pentyl group, and n-hexyl group. N-octyl group, n-nonyl group, n-decyl group, cyclopentyl group, cyclohexyl group, 2-ethylhexyl group, cyclopentylmethyl group, cyclopentylethyl group, cyclopentylbutyl group, cyclohexylmethyl group, cyclohexylethyl group, cyclohexylbutyl group , Norbornyl group, oxanorbornyl group, tricyclo [5.2.1.0 ^2,6 ] decanyl group, adamantyl group, phenyl group, naphthyl group, anthracenyl group and the like. Further, a part of hydrogen atoms of these groups may be substituted with a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, or a part of carbon atoms may be an oxygen atom, a sulfur atom, It may be substituted with a hetero atom such as a nitrogen atom, and as a result, a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, It may contain a haloalkyl group or 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, and a hexane-1,6-diyl group. , Heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1, 12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1,17-diyl group, etc. Linear alkanediyl group of the above; saturated cyclic divalent hydrocarbon group such as cyclopentanediyl group, cyclohexanediyl group, norbornanediyl group and adamantanediyl group; unsaturated cyclic group such as phenylene group and naphthylene group Valent hydrocarbon group, and the like. Moreover, some 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. Further, some 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 between some of the carbon atoms of these groups. Hetero atom containing groups such as oxygen atom, sulfur atom and nitrogen atom may be interposed, and as a result, hydroxy group, cyano group, carbonyl group, ether group, ester group, sulfonate group, carbonate group, lactone ring , Sultone ring, carboxylic acid anhydride, haloalkyl group and the like. The heteroatom is preferably an oxygen atom.

As a photo-acid generator represented by Formula (2), what is represented by following formula (2 ') is preferable.

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

Examples of the photoacid generator represented by formula (2) include, but are not limited to, those shown below. In the following formulas, L ^B is the same as defined above, Me represents a methyl group.

  Among the photoacid generators, those containing an anion represented by the formula (1A ′) or (1D) are particularly preferable because of low acid diffusion and excellent solubility in a resist solvent. Moreover, the thing containing the anion represented by Formula (2 ') has a very small acid diffusion, and is especially preferable.

  0.01-100 mass parts is preferable with respect to 100 mass parts of base resins, and, as for the compounding quantity of an acid generator, 0.1-80 mass parts is more preferable. An acid generator can be used individually by 1 type or in combination of 2 or more types.

[Organic solvent]
The resist material of the present invention may contain an organic solvent. Examples of the organic solvent include ketones such as cyclohexanone and methyl n-pentyl ketone described in paragraphs [0144] to [0145] of JP-A-2008-111103; 3-methoxybutanol, 3-methyl-3-methoxy Alcohols such as butanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol; propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether Ethers such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate Esters such as butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, t-butyl acetate, t-butyl propionate, propylene glycol mono t-butyl ether acetate; lactones such as γ-butyrolactone It is done. These solvents can be used alone or in combination of two or more.

  The blending amount of the organic solvent is preferably 50 to 10,000 parts by mass, more preferably 100 to 5,000 parts by mass with respect to 100 parts by mass of the base resin.

[Other ingredients]
The resist material of the present invention may further contain a basic compound, a dissolution controller, a surfactant, acetylene alcohols and the like.

  By adding a basic compound to the resist material, for example, the acid diffusion rate in the resist film can be suppressed, and the resolution can be further improved. Examples of the basic compound include those described in paragraphs [0146] to [0164] of JP-A-2008-111103. Of these, primary, secondary and tertiary amine compounds, particularly amine compounds containing a hydroxy group, an ether group, an ester group, a lactone ring, a cyano group, a sulfonic acid ester group and the like are preferable. 0-100 mass parts is preferable with respect to 100 mass parts of base resins, and, as for the compounding quantity of a basic compound, 0.001-50 mass parts is more preferable.

  By adding a surfactant to the resist material, the coating property of the resist material can be further improved or controlled. Examples of the surfactant include those described in paragraphs [0165] to [0166] of JP-A-2008-111103. 0-10 mass parts is preferable with respect to 100 mass parts of base resins, and, as for the compounding quantity of surfactant, 0.0001-5 mass parts is more preferable.

  By blending a dissolution control agent in the resist material, the difference in dissolution rate between the exposed area and the unexposed area can be further increased, and the resolution can be further improved. Examples of the dissolution control agent include those described in paragraphs [0155] to [0178] of JP-A-2008-122932. 0-50 mass parts is preferable with respect to 100 mass parts of base resins, and, as for the compounding quantity of a dissolution control agent, 0-40 mass parts is more preferable.

  Examples of acetylene alcohols include those described in paragraphs [0179] to [0182]. The blending amount of acetylene alcohols is preferably 0 to 2% by mass in the resist material, and more preferably 0.02 to 1% by mass.

  The resist material of the present invention may be blended with a polymer quencher described in JP-A-2008-239918. This can enhance the rectangularity of the resist after patterning by orienting on the resist surface after coating. The polymer quencher also has the effect of preventing pattern loss and pattern top rounding when a protective film is applied on the resist. When the polymer type quencher is included, the amount of the polymer quencher can be arbitrarily set within a range not impairing the effects of the present invention.

（式中、Ｒ¹⁵¹、Ｒ¹⁵²及びＲ¹⁵³は、それぞれ独立に、水素原子、フッ素原子を除くハロゲン原子、又はヘテロ原子を含んでいてもよい炭素数１〜４０の直鎖状、分岐状若しくは環状の１価炭化水素基を表す。また、Ｒ¹⁵¹、Ｒ¹⁵²及びＲ¹⁵³のうちのいずれか２つ以上が、互いに結合してこれらが結合する炭素原子と共に環を形成してもよい。Ｒ¹⁵⁴は、ヘテロ原子を含んでいてもよい炭素数１〜４０の直鎖状、分岐状又は環状の１価炭化水素基を表す。Ｍ⁺は、オニウムカチオンを表す。） In addition, the resist material of the present invention contains, as a quencher, a sulfonic acid that is not fluorinated at the α-position represented by the following formula (3) or an onium salt of a carboxylic acid represented by the following formula (4). May be.

(Wherein R ¹⁵¹ , R ¹⁵² and R ¹⁵³ are each independently a hydrogen atom, a halogen atom excluding a fluorine atom, or a linear or branched chain having 1 to 40 carbon atoms which may contain a hetero atom. Represents a cyclic monovalent hydrocarbon group, and any two or more of R ¹⁵¹ , R ¹⁵² and R ¹⁵³ may be bonded to each other to form a ring together with the carbon atom to which they are bonded. ¹⁵⁴ represents a linear, branched or cyclic monovalent hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom, and M ⁺ represents an onium cation.)

  The onium salt of sulfonic acid in which the α-position is not fluorinated is detailed in JP-A-2008-158339. Examples of the photoacid generator that generates a sulfonic acid that is not fluorinated at the α-position include compounds described in paragraphs [0019] to [0036] of JP2010-155824A, and JP2010-215608A. And compounds described in paragraphs [0047] to [0082]. The onium salt of carboxylic acid is detailed in Japanese Patent No. 3991462.

  The anion in formula (3) or (4) is a conjugate base of a weak acid. The term “weak acid” as used herein means an acidity that cannot deprotect the acid labile group of the acid labile group-containing unit used in the base resin. When the onium salt represented by the formula (3) or (4) is used in combination with an onium salt photoacid generator having a conjugate base of a strong acid such as a sulfonic acid having a fluorinated α-position as a counter anion To act as a quencher.

  That is, when an onium salt that generates a strong acid such as a sulfonic acid in which the α-position is fluorinated and an onium salt that generates a weak acid such as a sulfonic acid or a carboxylic acid not substituted with fluorine are used. When a strong acid generated from a photoacid generator upon irradiation with high energy rays collides with an onium salt having an unreacted weak acid anion, a weak acid is released by salt exchange to produce an onium salt having a strong acid anion. In this process, the strong acid is exchanged with a weak acid having a lower catalytic ability, so that the acid is apparently deactivated and the acid diffusion can be controlled.

  In particular, sulfonium salts and iodonium salts of sulfonic acids and carboxylic acids that are not fluorinated at the α-position are photodegradable, so that the quenching ability of the portion with high light intensity is reduced and the α-position is fluorinated. The concentration of the resulting sulfonic acid, imide acid or methide acid increases. As a result, it is possible to form a pattern with good dimension control in which the contrast of the exposed portion is improved and the depth of focus (DOF) is further improved.

  Here, when the photoacid generator that generates a strong acid is an onium salt, the strong acid generated by the high energy beam irradiation can be exchanged for the weak acid as described above, but the weak acid generated by the high energy beam irradiation can be exchanged. It is considered that salt exchange cannot be performed by colliding with an onium salt that generates an unreacted strong acid. This is due to the phenomenon that the onium cation is more likely to form an ion pair with a strong acid anion.

  When the acid labile group is an acetal that is particularly sensitive to acids, the acid for removing the protecting group does not necessarily need to be sulfonic acid, imide acid, or methide acid fluorinated at the α-position, The deprotection reaction may proceed even with a sulfonic acid in which the α-position is not fluorinated. Since the onium salt of sulfonic acid cannot be used as the quencher at this time, it is preferable to use the onium salt of carboxylic acid alone in such a case.

The onium salt of a sulfonic acid that is not fluorinated at the α-position and the onium salt of a carboxylic acid are represented by the onium salt of a sulfonic acid represented by the following formula (3 ′) and the following formula (4 ′), respectively. Sulphonium salts of carboxylic acids are preferred.

In the formula, R ²⁵¹ , R ²⁵² and R ²⁵³ each independently represent a linear, branched or cyclic monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. Further, any two or more of R ²⁵¹ , R ²⁵² and R ²⁵³ may be bonded to each other to form a ring together with the atoms to which they are bonded and the atoms in between. R ²⁵⁴ represents a linear, branched or cyclic monovalent hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom. R ²⁵⁵ and R ²⁵⁶ each independently represents a hydrogen atom or a trifluoromethyl group. ^R257 and ^R258 each independently represents a hydrogen atom, a fluorine atom or a trifluoromethyl group. R ²⁵⁹ is a hydrogen atom, a hydroxy group, a linear, branched or cyclic monovalent hydrocarbon group having 1 to 35 carbon atoms which may contain a hetero atom, or a substituted or unsubstituted group having 6 to 30 carbon atoms. Represents an aryl group. r represents an integer of 1 to 3. z ^1, z ² and z ³ each independently represents an integer of 0 to 5.

  When using such an onium salt as a quencher, it can be used individually by 1 type or in combination of 2 or more types. The blending amount is preferably 0 to 50 parts by weight, more preferably 0.001 to 50 parts by weight, and still more preferably 0.01 to 20 parts by weight with respect to 100 parts by weight of the base resin. By blending such a quencher within the above range, the resist sensitivity can be easily adjusted, the acid diffusion rate in the resist film is suppressed, the resolution is improved, and the sensitivity changes after exposure. It is possible to reduce the dependency on the substrate and the environment, and to improve the exposure margin and the pattern profile. In addition, the substrate adhesion can be improved by adding such a quencher.

  The resist material of the present invention may contain a polymer compound (water repellency improver) for improving the water repellency of the resist surface after spin coating. The water repellency improver can be used in immersion lithography that does not use a top coat. The water repellency improver is preferably a polymer compound containing a fluorinated alkyl group or a polymer compound containing a 1,1,1,3,3,3-hexafluoro-2-propanol residue having a specific structure. Examples are disclosed in Japanese Unexamined Patent Application Publication Nos. 2007-297590 and 2008-111103. The water repellency improver needs to be dissolved in an organic solvent developer. The above-mentioned water repellency improver having a specific 1,1,1,3,3,3-hexafluoro-2-propanol residue has good solubility in a developer. As a water repellency improver, a polymer compound copolymerized with an amino group or an amine salt as a repeating unit is highly effective in preventing evaporation of an acid in PEB and preventing a hole pattern from being poorly opened after development. When the water repellency improver is included, the blending amount is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the base resin of the resist material.

  In the exposed part, the base resin containing the polymer A is combined with an acid generator, an organic solvent, a dissolution control agent, a basic compound, a surfactant, and the like in an appropriate combination according to the purpose to constitute a resist material. Since the dissolution rate of the polymer A in the developer is accelerated by the catalytic reaction, a resist material with extremely high sensitivity can be obtained. The resist material of the present invention has a high dissolution contrast and resolution of the resist film obtained therefrom, an exposure margin, excellent process adaptability, a good pattern shape after exposure, and a better etching resistance. In particular, since the acid diffusion can be suppressed, the dimensional difference in density is small, and from these, the practicality is high and it is very effective as a resist material for VLSI. In particular, when a chemically amplified resist material using an acid catalyzed reaction by blending an acid generator is used, it can be made more sensitive, and various characteristics are further improved, making it extremely useful. .

[Pattern formation method]
When the resist material of the present invention, for example, a chemically amplified resist material containing a base resin, an acid generator, an organic solvent, and a basic compound is used for manufacturing various integrated circuits, a known lithography technique can be applied.

For example, the resist material of the present invention is applied to a substrate for manufacturing an integrated circuit (Si, SiO ₂ , SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflection film, etc.) or a substrate for manufacturing a mask circuit (Cr, CrO). , CrON, MoSi ₂ , SiO _2, etc.) so that the coating film thickness becomes 0.1 to 2.0 μm by an appropriate coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, etc. Apply to. This is preferably pre-baked on a hot plate at 60 to 150 ° C. for 10 seconds to 30 minutes, more preferably at 80 to 120 ° C. for 30 seconds to 20 minutes. A protective film may be formed on the resist film. The protective film is preferably soluble in an alkali developer. During development, the protective film is peeled off together with the formation of the resist pattern. The protective film has a function of reducing outgas from the resist film, a function as a filter for cutting out of band (OOB) of wavelengths 140 to 300 nm other than 13.5 nm generated from the EUV laser, and the shape of the resist due to the influence of the environment. Has the function of preventing the head from becoming a head or causing film loss. Next, the target pattern is exposed through a predetermined mask or directly with a light source selected from high energy rays such as ultraviolet rays, far ultraviolet rays, EUV, EB, X-rays, soft X-rays, excimer lasers, γ rays, and synchrotron radiation. Do. Exposure amount 1 to 200 mJ / cm ² or so, in particular 10 to 100 mJ / cm ^2, or 0.1~100μC / cm ² or so, it is preferable that exposure to particular a 0.5~50μC / cm ^2. Next, PEB is preferably performed on a hot plate at 60 to 150 ° C. for 10 seconds to 30 minutes, more preferably at 80 to 120 ° C. for 30 seconds to 20 minutes.

  Further, 0.1 to 10% by mass, preferably 2 to 5% by mass of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide ( Using an aqueous developer such as TBAH), development is performed for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, by a conventional method such as a dip method, a paddle method, or a spray method. Thus, when the polymer A contains the repeating units b1 and / or b2, the portion irradiated with light is dissolved in the developer, and the portion not irradiated is not dissolved, and a positive pattern is formed on the substrate. When the polymer A contains the repeating unit b3, a negative pattern is formed on the substrate. The resist material of the present invention is particularly suitable for fine patterning by EB, EUV, X-rays, soft X-rays, γ-rays and synchrotron radiation among high energy rays.

  TEAH, TPAH, TBAH, etc. having a longer alkyl chain than TMAH which is generally widely used have the effect of reducing swelling during development and preventing pattern collapse. Japanese Patent No. 3429592 includes a repeating unit containing an alicyclic structure such as adamantane methacrylate and a repeating unit containing an acid labile group such as t-butyl methacrylate, and has no hydrophilic group and high water repellency. An example using an aqueous TBAH solution for polymer development is presented.

  As the TMAH developer, a 2.38 mass% TMAH aqueous solution is most widely used. This corresponds to 0.26N, and it is preferable that aqueous solutions of TEAH, TPAH, TBAH, etc. have the same normality. The masses of TEAH, TPAH, and TBAH that are 0.26N are 3.84 mass%, 5.31 mass%, and 6.78 mass%, respectively.

  In a pattern of 32 nm or less that is resolved by EB or EUV, a phenomenon occurs in which the lines are twisted, the lines are stuck together, or the stuck lines are tilted. This is thought to be because the lines swollen and swollen in the developer are stuck together. Since the swollen line is soft like a sponge containing a developer, it tends to collapse due to the stress of rinsing. A developer having a long alkyl chain has the effect of preventing swelling and preventing pattern collapse.

  When the polymer A contains the repeating units b1 and / or b2, a negative pattern can be obtained by organic solvent development. As the developer, 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methyl acetophenone, 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 crotonic acid, ethyl crotonic acid, 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, phenyl acetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, phenyl ethyl acetate, 2-phenylethyl, and the like. These solvents can be used alone or in combination of two or more.

  At the end of development, rinse is performed. As the rinsing liquid, a solvent which is mixed with the developer and does not dissolve the resist film is preferable. As such a solvent, alcohols having 3 to 10 carbon atoms, ether compounds having 8 to 12 carbon atoms, alkanes having 6 to 12 carbon atoms, alkenes, alkynes, and aromatic solvents are preferably used.

  Specifically, as alcohol having 3 to 10 carbon atoms, n-propyl alcohol, isopropyl alcohol, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, t-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, t-pentyl 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-ethyl-1-butanol, 2-methyl-1-pen Tanol, 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-pen Examples include butanol, cyclohexanol, 1-octanol and the like.

  Examples of the ether compound having 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, and di-t-pentyl. Examples include 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, cyclooctane, and cyclononane. It is done. Examples of the alkene having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, and cyclooctene. Examples of the alkyne having 6 to 12 carbon atoms include hexyne, heptin, octyne and the like.

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

  EXAMPLES Hereinafter, although a synthesis example, a comparative synthesis example, an Example, and a comparative example are shown and this invention is demonstrated concretely, this invention is not limited to the following Example.

[1] Synthesis of Monomer [Synthesis Example 1] Synthesis of Monomer 1 45 g of 2-hydroxy-N-methylsuccinimide and 3.7 g of 4- (dimethylamino) pyridine were dissolved in 500 g of THF, and 92 ml of methacrylic acid chloride under ice cooling. 4 g was added dropwise. After stirring at room temperature for 5 hours, water was added to stop the reaction. After usual aqueous post-treatment, purification was performed by silica gel column chromatography to obtain 120 g of monomer 1.

[Synthesis Example 2] Synthesis of Monomer 2 128 g of Monomer 2 was obtained in the same manner as in Synthesis Example 1, except that methacrylic acid chloride was changed to 128 g of 2-carboxymethyl methacrylate.

[2] Synthesis of Polymer In the following synthesis examples, Mw is a measured value in terms of polystyrene by gel permeation chromatography (GPC) using THF as a solvent. Moreover, the monomers 3-4 and the PAG monomers 1-2 used in the following synthesis examples are as follows.

[Synthesis Example 2] flask 2L polymer 1, 5.6 g of methacrylic acid 1-isopropyl-exo-tetracyclo [4.4.0.1 ^{2, 5} .1 ^7,10] dodecanyl methacrylate 1-isopropyl 3.9 g of cyclopentyl, 2.2 g of 3-hydroxy-1-adamantyl methacrylate, 5.9 g of monomer 1, 5.9 g of 2-oxo-4,5-dimethyltetrahydrofuran-4-yl methacrylate, and solvent As a result, 40 g of THF was added. The reaction vessel was cooled to −70 ° C. in a nitrogen atmosphere, and vacuum degassing and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN was added as a polymerization initiator, and the temperature was raised to 60 ° C., followed by reaction for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered and then dried under reduced pressure at 60 ° C. to obtain a white polymer (Polymer 1).

When the obtained polymer was measured by ¹³ C-NMR, ¹ H-NMR and GPC, the following analysis results were obtained.
-Copolymer composition ratio (molar ratio)
Methacrylic acid 1-isopropyl-exo-tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodecanyl methacrylate: 1-isopropyl-cyclopentyl: 3-hydroxy-1-adamantyl methacrylate: Monomer 1: methacrylic acid 2 -Oxo-4,5-dimethyltetrahydrofuran-4-yl = 0.20: 0.20: 0.10: 0.20: 0.30
Mw = 7,500
Mw / Mn = 1.59

Synthesis Example 3 Synthesis of Polymer 2 In a 2 L flask, 11.7 g of monomer 3, 2.2 g of 3-hydroxy-1-adamantyl methacrylate, 5.9 g of monomer 1, 7.2 g of monomer 4, and 40 g of THF was added as a solvent. The reaction vessel was cooled to −70 ° C. in a nitrogen atmosphere, and vacuum degassing and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN was added as a polymerization initiator, and the temperature was raised to 60 ° C., followed by reaction for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered and dried under reduced pressure at 60 ° C. to obtain a white polymer (polymer 2).

When the obtained polymer was measured by ¹³ C-NMR, ¹ H-NMR and GPC, the following analysis results were obtained.
-Copolymer composition ratio (molar ratio)
Monomer 3: 3-hydroxy-1-adamantyl methacrylate: Monomer 1: Monomer 4 = 0.35: 0.10: 0.30: 0.25
Mw = 7,500
Mw / Mn = 1.59

Synthesis Example 4 Synthesis of Polymer 3 In a 2 L flask, 5.2 g of 1- (adamantan-1-yl) -1-methylethyl methacrylate, 3.1 g of 4- (1-methylcyclopentyloxy) styrene, 8.9 g of monomer 1, 4.4 g of 4-hydroxyphenyl methacrylate, 11.0 g of PAG monomer 1 and 40 g of THF as a solvent were added. The reaction vessel was cooled to −70 ° C. in a nitrogen atmosphere, and vacuum degassing and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN was added as a polymerization initiator, and the temperature was raised to 60 ° C., followed by reaction for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered and dried under reduced pressure at 60 ° C. to obtain a white polymer (Polymer 3).

When the obtained polymer was measured by ¹³ C-NMR, ¹ H-NMR and GPC, the following analysis results were obtained.
-Copolymer composition ratio (molar ratio)
1- (Adamantane-1-yl) methacrylic acid methacrylate: 4- (1-methylcyclopentyloxy) styrene: monomer 1: 4-hydroxyphenyl methacrylate: PAG monomer 1 = 0.20: 0.15: 0.30: 0.20: 0.15
Mw = 9,300
Mw / Mn = 1.76

[Synthesis Example 5] Synthesis of Polymer 4 13.7 g of 4-methylcyclohexyloxyphenyl methacrylate, 8.9 g of monomer 1, 16.0 g of PAG monomer 2 and 40 g of THF as a solvent were added to a 2 L flask. . The reaction vessel was cooled to −70 ° C. in a nitrogen atmosphere, and vacuum degassing and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN was added as a polymerization initiator, and the temperature was raised to 60 ° C., followed by reaction for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered and then dried under reduced pressure at 60 ° C. to obtain a white polymer (polymer 4).

When the obtained polymer was measured by ¹³ C-NMR, ¹ H-NMR and GPC, the following analysis results were obtained.
-Copolymer composition ratio (molar ratio)
4-methylcyclohexyloxyphenyl methacrylate: monomer 1: PAG monomer 2 = 0.50: 0.30: 0.20
Mw = 8,300
Mw / Mn = 1.74

The flask 2L of Synthesis Example 5 Polymer 5, 5.6 g of methacrylic acid 1-isopropyl-exo-tetracyclo [4.4.0.1 ^{2, 5} .1 ^7,10] dodecanyl methacrylate 1-isopropyl 3.9 g of cyclopentyl, 2.2 g of 3-hydroxy-1-adamantyl methacrylate, 12.9 g of monomer 2 and 40 g of THF as a solvent were added. The reaction vessel was cooled to −70 ° C. in a nitrogen atmosphere, and vacuum degassing and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN was added as a polymerization initiator, and the temperature was raised to 60 ° C., followed by reaction for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered and dried under reduced pressure at 60 ° C. to obtain a white polymer (Polymer 5).

When the obtained polymer was measured by ¹³ C-NMR, ¹ H-NMR and GPC, the following analysis results were obtained.
-Copolymer composition ratio (molar ratio)
Methacrylic acid 1-isopropyl-exo-tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodecanyl methacrylate: 1-isopropyl-cyclopentyl: 3-hydroxy-1-adamantyl methacrylate: monomer 2 = 0.20 : 0.20: 0.10: 0.50
Mw = 8,500
Mw / Mn = 1.95

[Comparative Synthesis Example 1]
Comparative polymer 1 was synthesized in the same manner as in Synthesis Example 2 except that monomer 1 was not used.
-Copolymer composition ratio (molar ratio)
Methacrylic acid 1-isopropyl-exo-tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodecanyl methacrylate: 1-isopropyl-cyclopentyl: 3-hydroxy-1-adamantyl methacrylate: methacrylic acid 2-oxo - 4,5-dimethyltetrahydrofuran-4-yl = 0.20: 0.20: 0.10: 0.50
Mw = 8,900
Mw / Mn = 1.71

[Comparative Synthesis Example 2] Synthesis of Comparative Polymer 2 Comparative polymer 2 was synthesized in the same manner as in Synthesis Example 3 except that 2-oxo-4,5-dimethyltetrahydrofuran methacrylate was used in place of monomer 1.
-Copolymer composition ratio (molar ratio)
Monomer 2: 3-hydroxy-1-adamantyl methacrylate: 2-oxo-4,5-dimethyltetrahydrofuran methacrylate: monomer 3 = 0.35: 0.10: 0.30: 0.25
Mw = 7,700
Mw / Mn = 1.51

[Comparative Synthesis Example 3]
Comparative polymer 3 was synthesized in the same manner as in Synthesis Example 4 except that 2-oxotetrahydrofuran-3-yl methacrylate was used in place of monomer 1.
-Copolymer composition ratio (molar ratio)
1- (Adamantane-1-yl) methacrylic acid methacrylate: 4- (1-methylcyclopentyloxy) styrene: 2-oxotetrahydrofuran-3-yl methacrylate: 4-hydroxyphenyl methacrylate: PAG monomer 1 = 0.20: 0.15: 0.30: 0.20: 0.15
Mw = 9,100
Mw / Mn = 1.78

[3] ArF exposure patterning evaluation [Examples 1-1 to 1-3, Comparative Examples 1-1 to 1-2]
A solution obtained by dissolving each component with the composition shown in Table 1 in a solvent in which 100 ppm of surfactant FC-4430 manufactured by Sumitomo 3M Co., Ltd. is dissolved, is filtered through a 0.2 μm size filter to form a positive resist material ( R-1 to R-5) were prepared.
Each composition in Table 1 is as follows.
Organic solvent: PGMEA (propylene glycol monomethyl ether acetate)
GBL (γ-butyrolactone)
Acid generator: PAG1
Quencher: Quencher1
Water repellent polymer 1: Mw = 12,800, Mw / Mn = 1.71

The prepared resist material (R-1 to R-5) is spin-on carbon film ODL-101 (carbon content is 80% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. on a silicon wafer at 160 nm, and silicon-containing spin-on A hard mask SHB-A940 (silicon content: 43% by mass) was spin-coated on a substrate for a trilayer process having a film thickness of 35 nm, and baked at 80 ° C. for 60 seconds using a hot plate. A resist film having a thickness of 80 nm was prepared.
This is an ArF excimer laser immersion scanner (manufactured by Nikon Corporation, NSR-610C, NA1.30, σ0.98 / 0.78, cross pole opening 20 degrees, Azimuthally polarized illumination, 6% halftone phase shift mask, dimensions on wafer) Using a 90 nm pitch and 30 nm line width mask), the exposure is performed while changing the exposure amount. After the exposure, PEB is performed for 60 seconds at the temperature shown in Table 2, and the developer described in Table 2 is supplied from the developing nozzle. Was discharged while rotating at 30 rpm for 3 seconds, followed by stationary paddle development for 27 seconds and spin drying to obtain a negative pattern.

  The dimensions of 50 hole patterns obtained by reversing the image of the solvent development were measured with TDSEM (CG-4000) manufactured by Hitachi High-Technologies Corporation, and the 3σ dimension variation was determined. The cross-sectional shape of the hole pattern was observed with an electron microscope S-4300 manufactured by Hitachi High-Technologies Corporation. The results are shown in Table 2.

  From the results shown in Table 2, the resist material of the present invention was excellent in pattern dimensional uniformity.

[4] EB drawing evaluation [Examples 2-1 to 2-2, Comparative example 2-1]
A solution obtained by dissolving each component with the composition shown in Table 3 in a solvent in which 100 ppm of surfactant FC-4430 manufactured by Sumitomo 3M Co., Ltd. is dissolved, is filtered through a 0.2 μm size filter to form a positive resist material ( R-6 to R-8) were prepared.
Each composition in Table 3 is as follows.
Organic solvent: PGMEA (propylene glycol monomethyl ether acetate)
PGME (propylene glycol monomethyl ether)
CyH (cyclohexanone)
Basic compound: Amine1

Using the clean resist Mark 5 (manufactured by Tokyo Electron Co., Ltd.) on a Si substrate obtained by treating the prepared resist material (R-6 to R-8) with a hexamethyldisilazane (HMDS) vapor prime having a diameter of 6 inches φ. Spin coating was performed and prebaked on a hot plate at 110 ° C. for 60 seconds to prepare a resist film having a thickness of 100 nm. To this, drawing in a vacuum chamber was performed at an HV voltage of 50 kV using HL-800D manufactured by Hitachi, Ltd.
Immediately after drawing, PEB was performed for 60 seconds on a hot plate at a temperature shown in Table 4 using a clean track Mark 5, and paddle development was performed for 30 seconds with a 2.38 mass% TMAH aqueous solution to obtain a positive pattern. It was.

The obtained resist pattern was evaluated as follows.
The minimum dimension at the exposure amount for resolving 100 nm line and space at 1: 1 was taken as the resolving power, and the edge roughness (LWR) of 100 nm LS was measured by SEM. The results are shown in Table 4.

The ratio of the repeating unit c is 0 ≦ c ≦ 0.9. When the repeating unit c is included, it is preferably 0 <c ≦ 0.9 and 0.2 ≦ a + b + c ≦ 1.0. Here, when the repeating unit b is the repeating units b1 and b2, more preferably 0.02 ≦ a ≦ 0.8, 0 ≦ b1 ≦ 0.8, 0 ≦ b2 ≦ 0.8, 0.1 ≦. b1 + b2 ≦ 0.8, 0.1 ≦ c ≦ 0.88, more preferably 0.05 ≦ a ≦ 0.75, 0 ≦ b1 ≦ 0.7, 0 ≦ b2 ≦ 0.7, 0.1 ≦ b1 + b2. ≦ 0.75, 0.15 ≦ c ≦ 0.85, particularly preferably 0.07 ≦ a ≦ 0.7, 0 ≦ b1 ≦ 0.65, 0 ≦ b2 ≦ 0.65, 0.1 ≦ b1 + b2 ≦ 0.7, 0.2 ≦ c ≦ 0.83. In this case, 0.2 ≦ a + b1 + b2 + c ≦ 1.0, more preferably 0.3 ≦ a + b1 + b2 + c ≦ 1.0, and still more preferably 0.4 ≦ a + b1 + b2 + c ≦ 1.0. When the repeating unit b is the repeating unit b3, more preferably 0.02 ≦ a ≦ 0.8, 0.1 ≦ b3 ≦ 0.8, 0.1 ≦ c ≦ 0.88, and still more preferably 0.8. 05 ≦ a ≦ 0.75, 0.1 ≦ b3 ≦ 0.75, 0.15 ≦ c ≦ 0.85, particularly preferably 0.07 ≦ a ≦ 0.7, 0.1 ≦ b3 ≦ 0.7 0.2 ≦ c ≦ 0.83. In this case, 0.2 ≦ a + b 3 + c ≦ 1.0, more preferably 0.3 ≦ a + b3 + c ≦ 1.0, and still more preferably 0.4 ≦ a + b3 + c ≦ 1.0.

In Synthesis Example 3 flask 2L polymer 1, methacrylic acid 1-isopropyl-exo-tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] 5.6g dodecanyl, methacrylic acid 1-isopropyl 3.9 g of cyclopentyl, 2.2 g of 3-hydroxy-1-adamantyl methacrylate, 5.9 g of monomer 1, 5.9 g of 2-oxo-4,5-dimethyltetrahydrofuran-4-yl methacrylate, and solvent As a result, 40 g of THF was added. The reaction vessel was cooled to −70 ° C. in a nitrogen atmosphere, and vacuum degassing and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN was added as a polymerization initiator, and the temperature was raised to 60 ° C., followed by reaction for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered and then dried under reduced pressure at 60 ° C. to obtain a white polymer (Polymer 1).

Synthesis Example 4 Synthesis of Polymer 2 In a 2 L flask, 11.7 g of monomer 3, 2.2 g of 3-hydroxy-1-adamantyl methacrylate, 5.9 g of monomer 1, 7.2 g of monomer 4, and 40 g of THF was added as a solvent. The reaction vessel was cooled to −70 ° C. in a nitrogen atmosphere, and vacuum degassing and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN was added as a polymerization initiator, and the temperature was raised to 60 ° C., followed by reaction for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered and dried under reduced pressure at 60 ° C. to obtain a white polymer (polymer 2).

Synthesis Example 5 Synthesis of Polymer 3 In a 2 L flask, 5.2 g of 1- (adamantan-1-yl) -1-methylethyl methacrylate, 3.1 g of 4- (1-methylcyclopentyloxy) styrene, 8.9 g of monomer 1, 4.4 g of 4-hydroxyphenyl methacrylate, 11.0 g of PAG monomer 1 and 40 g of THF as a solvent were added. The reaction vessel was cooled to −70 ° C. in a nitrogen atmosphere, and vacuum degassing and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN was added as a polymerization initiator, and the temperature was raised to 60 ° C., followed by reaction for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered and dried under reduced pressure at 60 ° C. to obtain a white polymer (Polymer 3).

[Synthesis Example 6 ] Synthesis of Polymer 4 To a 2 L flask, 13.7 g of 4-methylcyclohexyloxyphenyl methacrylate, 8.9 g of monomer 1, 16.0 g of PAG monomer 2 and 40 g of THF as a solvent were added. . The reaction vessel was cooled to −70 ° C. in a nitrogen atmosphere, and vacuum degassing and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN was added as a polymerization initiator, and the temperature was raised to 60 ° C., followed by reaction for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered and then dried under reduced pressure at 60 ° C. to obtain a white polymer (polymer 4).

The flask 2L of Synthesis Example 7 Polymer 5, 5.6 g of methacrylic acid 1-isopropyl-exo-tetracyclo [4.4.0.1 ^{2, 5} .1 ^7,10] dodecanyl methacrylate 1-isopropyl 3.9 g of cyclopentyl, 2.2 g of 3-hydroxy-1-adamantyl methacrylate, 12.9 g of monomer 2 and 40 g of THF as a solvent were added. The reaction vessel was cooled to −70 ° C. in a nitrogen atmosphere, and vacuum degassing and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN was added as a polymerization initiator, and the temperature was raised to 60 ° C., followed by reaction for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered and dried under reduced pressure at 60 ° C. to obtain a white polymer (Polymer 5).

[Comparative Synthesis Example 1]
Comparative polymer 1 was synthesized in the same manner as in Synthesis Example 3 except that monomer 1 was not used.
-Copolymer composition ratio (molar ratio)
Methacrylic acid 1-isopropyl-exo-tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodecanyl methacrylate: 1-isopropyl-cyclopentyl: 3-hydroxy-1-adamantyl methacrylate: methacrylic acid 2-oxo - 4,5-dimethyltetrahydrofuran-4-yl = 0.20: 0.20: 0.10: 0.50
Mw = 8,900
Mw / Mn = 1.71

[Comparative Synthesis Example 2] Synthesis of Comparative Polymer 2 Comparative polymer 2 was synthesized in the same manner as in Synthesis Example 4 except that 2-oxo-4,5-dimethyltetrahydrofuran methacrylate was used instead of monomer 1.
-Copolymer composition ratio (molar ratio)
Monomer 3 : 3-hydroxy-1-adamantyl methacrylate: 2-oxo-4,5-dimethyltetrahydrofuran methacrylate: monomer 4 = 0.35: 0.10: 0.30: 0.25
Mw = 7,700
Mw / Mn = 1.51

[Comparative Synthesis Example 3]
Comparative polymer 3 was synthesized in the same manner as in Synthesis Example 5 except that 2-oxotetrahydrofuran-3-yl methacrylate was used in place of monomer 1.
-Copolymer composition ratio (molar ratio)
1- (adamantan-1-yl) methacrylic acid methacrylate: 4- (1-methylcyclopentyloxy) styrene: 2-oxotetrahydrofuran-3-yl methacrylate: 4-hydroxyphenyl methacrylate: PAG monomer 1 = 0.20: 0.15: 0.30: 0.20: 0.15
Mw = 9,100
Mw / Mn = 1.78

Claims (12)

A resist material comprising a base resin comprising a repeating unit represented by the following formula (a) and a repeating unit containing a group whose polarity is changed by an acid and having a weight average molecular weight of 1,000 to 500,000 .

(In the formula, R ¹ represents a hydrogen atom or a methyl group. R ² represents a hydrogen atom, a straight chain having 1 to 8 carbon atoms, a branched or cyclic alkyl group, or a straight chain having 2 to 6 carbon atoms. Represents a branched or cyclic acyl group, or a linear, branched or cyclic alkoxycarbonyl group having 2 to 6 carbon atoms, and X ¹ represents a single bond, a phenylene group, a naphthylene group, an ester group or an ether group. Alternatively, it represents a linking group having 1 to 12 carbon atoms including a lactone ring, and a represents a positive number satisfying 0 <a <1.0.   The resist material according to claim 1, wherein the polarity change due to the acid is caused by an elimination reaction.   3. The resist material according to claim 1, wherein the repeating unit containing a group whose polarity is changed by an acid contains a carboxyl group or a phenolic hydroxy group substituted with an acid labile group. The resist material according to claim 3, wherein the repeating unit containing a group whose polarity is changed by an acid is represented by the following formula (b1) or (b2).

(In the formula, R ³ and R ⁵ each independently represent a hydrogen atom or a methyl group. R ⁴ and R ⁸ each independently represent an acid labile group. R ⁶ represents a single bond or carbon. Represents a linear or branched alkylene group having 1 to 6. R ⁷ represents a hydrogen atom, a fluorine atom, a trifluoromethyl group, a cyano group, a linear, branched or cyclic group having 1 to 6 carbon atoms. , An alkyl group or an alkoxy group, or a linear, branched or cyclic acyl group, acyloxy group or alkoxycarbonyl group having 2 to 7 carbon atoms, p represents 1 or 2, and q represents 0 to 0. Represents an integer of 4. Y ¹ represents a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms including an ester group, an ether group, or a lactone ring, Y ² represents a single bond, —C (═O) —O— or —C (═O) —NH— .b1 and b2 represent positive numbers satisfying 0 ≦ b1 <1.0,0 ≦ b2 <1.0, and 0 <b1 + b2 <1.0.)   The resist material according to claim 1 or 2, wherein the repeating unit containing a group whose polarity is changed by an acid is a repeating unit that changes from hydrophilic to hydrophobic by a dehydration reaction with an acid. The resist material according to claim 5, wherein the repeating unit containing a group whose polarity is changed by an acid is derived from a monomer represented by the following formula.

(Wherein R ⁹ represents a hydrogen atom or a methyl group.)   The polymer further includes a hydroxy group, a carboxyl group, a lactone ring, a carbonate group, a thiocarbonate group, a carbonyl group, a cyclic acetal group, an ether group, an ester group, a sulfonic acid ester group, a cyano group, an amide group, and —O—. The resist material according to claim 1, comprising a repeating unit containing an adhesive group selected from C (═O) —G— (G is —S— or —NH—). The resist material according to claim 1, wherein the polymer further contains at least one repeating unit selected from the following formulas (d1) to (d3).

(In the formula, R ²⁰ , R ²⁴ and R ²⁸ each independently represent a hydrogen atom or a methyl group. R ²¹ represents a single bond, a phenylene group, —O—R ^A —, or —C (═O). —Y ⁰ —R ^A —, Y ⁰ represents —O— or —NH—, and R ^A may contain a carbonyl group, an ester group, an ether group or a hydroxy group. 6 represents a linear, branched or cyclic alkylene group, a linear, branched or cyclic alkenylene group having 2 to 6 carbon atoms, or a phenylene group, R ²² , R ²³ , R ²⁵ , R ²⁶ , R ²⁷ , R ²⁹ , R ³⁰ and R ³¹ are each independently a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms which may contain a carbonyl group, an ester group or an ether group, or a hydroxy group. Group, an aryl group having 6 to 12 carbon atoms, or an aryl group having 7 to 20 carbon atoms. Represents a aralkyl group or a mercaptophenyl group, and Z ¹ represents a single bond, an ether group, an ester group or a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms which may contain a lactone ring, or A linear, branched or cyclic alkenylene group having 2 to 12 carbon atoms, or an arylene group having 6 to 10 carbon atoms, Z ² represents a single bond, a methylene group, an ethylene group, a phenylene group, or a fluorinated group. Represents a phenylene group, —O—R ³² —, or —C (═O) —Z ³ —R ³² —, Z ³ represents —O— or —NH—, and R ³² represents a carbonyl group or an ester group. , .M of an ether group or hydroxy group of which may contain carbon atoms of 1 to 12 linear, branched or cyclic, alkylene or alkenylene group, or a phenylene group ^- is a non-nucleophilic counter .d1~d3 representing the ON represents a positive number satisfying 0 ≦ d1 ≦ 0.5,0 ≦ d2 ≦ 0.5,0 ≦ d3 ≦ 0.5, and 0 <d1 + d2 + d3 ≦ 0.5.)   Furthermore, the resist material of any one of Claims 1-8 containing an acid generator and an organic solvent.   Furthermore, the resist material of any one of Claims 1-9 containing a basic compound and / or surfactant.   A pattern forming method comprising: a step of applying the resist material according to claim 1 on a substrate; a step of exposing to high energy rays after heat treatment; and a step of developing using a developer. .   The pattern forming method according to claim 11, wherein the high energy beam is an i-line, a KrF excimer laser, an ArF excimer laser, an electron beam, or extreme ultraviolet rays having a wavelength in the range of 3 to 15 nm.