JP6642345B2 - Resist material and pattern forming method - Google Patents

Description

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

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

  Very short-wavelength high-energy rays such as electron beams (EB) and X-rays are hardly absorbed by hydrocarbons used in resist materials, and therefore are mainly composed of hydrocarbons. A resist material is being studied.

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

  Here, with the increase in the acceleration voltage, the reduction in 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 the electron drawing energy is improved and the resolution and dimensional controllability are improved. As a result, the sensitivity of the resist film decreases. Since the mask exposure machine exposes the image with one-stroke drawing directly, a decrease in the sensitivity of the resist film leads to a decrease in productivity, which is not preferable. Due to the demand for higher sensitivity, chemically amplified resist materials are being studied.

  With the progress of miniaturization, image blurring due to diffusion of acid has become a problem. In order to ensure resolution in a fine pattern having a size of 45 nm or less, it has been proposed that not only improvement in the solubility contrast conventionally proposed but also control of acid diffusion is important (Non-Patent Document) 1). However, since chemically amplified resist materials increase sensitivity and contrast by diffusion of acid, reducing the temperature and time of post-exposure bake (PEB) to minimize acid diffusion significantly reduces sensitivity and contrast. .

  The relationship between the sensitivity, the resolution, and the triangle trade-off of the edge roughness is shown. Here, it is necessary to suppress the acid diffusion in order to improve the resolution, but the sensitivity decreases as the acid diffusion distance becomes shorter.

  It is effective to add an acid generator that generates a bulky acid to suppress acid diffusion. Therefore, it has been proposed that a polymer contains a repeating unit derived from an onium salt containing a polymerizable unsaturated bond 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 a main chain.

  Investigations have also been made to suppress acid diffusion using techniques other than bulky acid generators. Patent Literatures 3 to 8 disclose adhesive groups containing a nitrogen atom. The presence of a nitrogen atom electron pair is effective for controlling acid diffusion. However, the nitrogen atom may not only prevent acid diffusion but also suppress the acid-catalyzed reaction. In this case, the deprotection reaction does not proceed, or even if it proceeds, the speed is slow, so that the contrast is reduced. Problems arise.

JP 2006-045311A JP 2006-178317 A JP 2011-203656 A International Publication No. 2011/024953 WO 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, and a resist material which reduces acid diffusion, has a higher resolution than conventional resist materials, has a small edge roughness (LER, LWR), and provides a good pattern shape. An object of the present invention is to provide a pattern forming method using a resist material.

  The present inventors have been intensively studying in recent years to obtain a resist material having high sensitivity, high resolution and small edge roughness, and as a result, have found that a polymer containing a repeating unit containing a succinimide structure contains a resist material, particularly It has been found that it is extremely effective if used as a base resin for a chemically amplified resist material.

  Further, the present inventors, in order to improve the dissolution contrast by suppressing acid diffusion, 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 of chemically amplified resist material, it has high sensitivity, extremely 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 having good edge roughness and particularly suitable for use in the manufacture of VLSI or for forming a fine pattern of a photomask, in particular, a chemically amplified resist material can be obtained.

  The resist material of the present invention can increase the decomposition efficiency of the acid generator, in particular, is highly sensitive, has a high effect of suppressing acid diffusion, has high resolution, has low edge roughness, and has process adaptability. And the pattern shape after exposure is good. Therefore, it has these excellent properties and is extremely practical, and is very effective as a resist material for ultra LSI 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１のレジスト材料。

（式中、Ｒ⁹は、水素原子又はメチル基を表す。）
３．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又は２のレジスト材料。
４．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１〜３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。）
５．更に、酸発生剤及び有機溶剤を含む１〜４のいずれかのレジスト材料。
６．更に、塩基性化合物及び／又は界面活性剤を含む１〜５のいずれかのレジスト材料。
７．１〜６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。
８．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７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 containing a polymer having 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. And
A resist material, 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 .

(In the formula, R ¹ represents a hydrogen atom or a methyl group. R ² represents a hydrogen atom, a linear or branched or cyclic alkyl group having 1 to 8 carbon atoms, a linear alkyl group 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, or an ester group or an ether group. Or a linking group having a carbon number of 1 to 12 containing a lactone ring. A represents a positive number satisfying 0 <a <1.0.)
2 . 1. The resist material according to 1 , wherein the repeating unit containing a group whose polarity is changed by an acid is derived from a monomer represented by the following formula.

(In the formula, R ⁹ represents a hydrogen atom or a methyl group.)
3 . The polymer further comprises 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 ester group, a cyano group, an amide group, and -O- 1 or 2 resist materials containing a repeating unit containing an adhesive group selected from C (= O) -G- (G is -S- or -NH-).
4 . The resist material according to any one of 1 to 3 , wherein the polymer further contains at least one repeating unit selected from the following formulas (d1) to (d3).

(Wherein 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 - represents, Y ⁰ represents -O- or -NH-, R ^a is a carbonyl group, an ester group, which may contain an ether group or hydroxy group, 1 carbon atoms A linear, branched or cyclic alkylene group having 6 or a linear, branched or cyclic alkenylene group having 2 to 6 carbon atoms, or a phenylene group, represented by R ²² , R ²³ , R ²⁵ , R ²⁶ , R ²⁷ , R ²⁹ , R ³⁰ and R ³¹ each independently represent 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, and a hydroxy group. Or an aryl group having 6 to 12 carbon atoms, an aryl group having 7 to 20 carbon atoms. Represents a aralkyl group or a mercaptophenyl group, Z ¹ is a single bond, or a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms which may contain an ether group, an ester group or a lactone ring, or Represents a linear, branched or cyclic alkenylene group having 2 to 12 carbon atoms or an arylene group having 6 to 10 carbon atoms, and Z ² represents a single bond, a methylene group, an ethylene group, a phenylene group, or a fluorinated group. phenylene, -O-R ³² -, or ^{-C (= O) -Z 3 -R} 32 - represents, Z ³ represents -O- or -NH-, R ³² is a carbonyl group, 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.)
5 . Further, any one of the resist materials 1 to 4 further comprising an acid generator and an organic solvent.
6 . Further, any one of the resist materials 1 to 5 , further comprising a basic compound and / or a surfactant.
7 . A pattern forming method, comprising: a step of applying any one of the resist materials 1 to 6 on a substrate; a step of exposing with a high energy ray after a heat treatment; and a step of developing with a developer.
<8 . 7. The pattern forming method according to 7 , wherein the high energy ray is an i-line, a KrF excimer laser, an ArF excimer laser, EB, or EUV having a wavelength of 3 to 15 nm.

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

  Further, the resist material of the present invention, in particular, a chemically amplified resist material can be used not only for lithography in forming a semiconductor circuit, but also for forming a mask circuit pattern, or for forming a micro machine or a thin film magnetic head circuit.

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

In the formula, R ¹ represents a hydrogen atom or a methyl group. R ² represents 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 a C ² to C 6 Represents a linear, branched or cyclic alkoxycarbonyl group. 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 described 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 reacting a compound represented by the following formula (a1) with a compound represented by the following formula (a2).

Wherein R ¹ , R ² and X ¹ are the same as above. X ² represents a hydrogen atom, a chlorine atom, a halogen atom such as 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 the following, but are not limited thereto. In the following formula, R ¹ is the same as described above.

  The repeating unit a is characterized by containing a succinimide structure. An amide group or carbamate group containing both a nitrogen atom and an oxygen atom has a disadvantage that the effect of suppressing acid diffusion is too high to suppress the deprotection reaction, but the succinimide structure has two carbonyl groups around the nitrogen atom. Is present, the nitrogen atom has a low basicity and does not inhibit the acid-catalyzed deprotection reaction. Nevertheless, the effect of suppressing acid diffusion by the unpaired electrons of the nitrogen atom is high. Adhesion is secured by the three carbonyl groups, and acid diffusion can be suppressed by unpaired electrons of the nitrogen atom, whereby pattern collapse and edge roughness (LWR) can be reduced.

Examples of the repeating unit containing a group whose polarity is changed by an acid (hereinafter, also referred to as a 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 a repeating unit b1) or a repeating unit represented by the following formula (b2) (hereinafter, also referred to as a repeating unit b2). Is preferred. When the repeating unit b1 and / or b2 is used, the resist material of the present invention can be used as a positive resist material for obtaining a positive pattern by alkali development or a negative resist material for obtaining a negative pattern by organic solvent development. .

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 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 straight, branched or cyclic, alkyl group or alkoxy group, or a number 2-7 straight , 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 satisfying 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).

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

Examples of the linking group having 1 to 12 carbon atoms containing a lactone ring represented by Y ¹ include the following.

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

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

The acid labile groups represented by R ⁴ in formula (Mb1) and R ⁸ in formula (Mb2) are variously selected, but may be the same or different. The acid labile groups described in JP-A-2013-83821 can be used.

Typically, those represented by the following formula can be 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, particularly 1 to 20 carbon atoms, and oxygen, sulfur, It may contain a hetero atom such as nitrogen or fluorine. R ⁵² and R ⁵³ each independently represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, such as a linear, branched or cyclic alkyl group, and include oxygen, sulfur, nitrogen, fluorine, etc. May be included. 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 have a carbon number of 3 to 20, preferably 4 to 4 together with a carbon atom or a carbon atom and an oxygen atom to which they are bonded. Sixteen rings, in particular, alicyclic rings may be formed.

R ⁵⁵ , R ⁵⁶ and R ⁵⁷ each independently represent a monovalent hydrocarbon group having 1 to 20 carbon atoms such as a linear, branched or cyclic alkyl group, and include oxygen, sulfur, nitrogen and fluorine. It may contain heteroatoms. R ⁵⁵ and R ⁵⁶ , R ⁵⁵ and R ⁵⁷ , or R ⁵⁶ and R ⁵⁷ are bonded to each other to form a ring having 3 to 20, preferably 4 to 16 carbon atoms, together with the carbon atom to which they are bonded. 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 giving the repeating unit b3 include, but are not limited to, the following. In the following formula, R ⁹ represents a hydrogen atom or a methyl group.

  Polymer A further comprises 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 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 giving the repeating unit c include, but are not limited to, the following.

  In the case of a monomer containing a hydroxy group, the hydroxy group may be replaced with an acetal group that is easily deprotected by an acid such as an ethoxyethoxy group during polymerization, and may be deprotected with a weak acid and water after the polymerization, or an acetyl group, Alkaline hydrolysis may be carried out after polymerization after substitution with a formyl group, pivaloyl group or the like.

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 - represents, Y ⁰ represents -O- or -NH-, R ^A Is a linear, branched or cyclic alkylene 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 linear or branched alkylene group having 2 to 6 carbon atoms. Or 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 represent a carbonyl group, an ester group or an ether group, or a carbon number of 1 to 5, which may contain a hydroxy group. It represents a 12 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 linear, branched or cyclic alkylene group having 1 to 12 carbon atoms which may contain an ether group, an ester group or a lactone ring, or a linear chain having 2 to 12 carbon atoms. , 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 It represents -O- or -NH-, R ³² is a carbonyl group, an ester group, an ether group or hydroxy group of which may contain 1 to 12 carbon atoms linear, branched or cyclic, alkylene group Or an alkenylene group or a phenylene group. M ^- represents a non-nucleophilic counter ion. d1 to d3 are positive numbers satisfying 0 ≦ d1 ≦ 0.5, 0 ≦ d2 ≦ 0.5, 0 ≦ d3 ≦ 0.5, and 0 <d1 + d2 + d3 ≦ 0.5.

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

M ^- as a non-nucleophilic counter ion represented by the chloride ion, halide ions such as bromide ion, triflate, 1,1,1-trifluoroethane sulfonate, fluoroalkyl sulfonate such as nonafluorobutanesulfonate; Arylsulfonates such as tosylate, benzenesulfonate, 4-fluorobenzenesulfonate, 1,2,3,4,5-pentafluorobenzenesulfonate; alkylsulfonates such as mesylate and butanesulfonate; bis (trifluoromethylsulfonyl) imide, bis ( Imide acids such as perfluoroethylsulfonyl) imide and bis (perfluorobutylsulfonyl) imide; and methide acids such as tris (trifluoromethylsulfonyl) methide and tris (perfluoroethylsulfonyl) methide.

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

In the 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 a group, and may contain an ether group, an ester group, a carbonyl group, a lactone ring, or a fluorine atom.

In the formula (K-2), R ⁴² is 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 include an ether group, an ester group, a carbonyl group, or a lactone ring. .

  When a polymer containing at least one repeating unit selected from repeating units d1 to d3 is used, the blending of a photoacid generator described later can be omitted.

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

In the formula, R ^{110 to} R ¹¹⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, or a carbon atom having 1 to 30 carbon atoms in which some or all of the hydrogen atoms bonded to the carbon atoms 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 include a repeating unit f derived from styrene, vinylnaphthalene, vinylanthracene, vinylpyrene, methyleneindane, or the like.

  As a method for synthesizing the polymer A, for example, a method in which a desired monomer among the monomers giving the repeating units a to f is heated and polymerized by adding a radical polymerization initiator in an organic solvent can be used.

  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. Examples of the polymerization initiator include 2,2′-azobisisobutyronitrile (AIBN), 2,2′-azobis (2,4-dimethylvaleronitrile), and dimethyl-2,2-azobis (2-methylpropionate). Benzoyl peroxide, lauroyl peroxide and the like. The reaction temperature is preferably from 50 to 80 ° C, and the reaction time is preferably from 2 to 100 hours, more preferably from 5 to 20 hours.

  When synthesizing a polymer containing a repeating unit derived from hydroxystyrene or hydroxyvinylnaphthalene, acetoxystyrene or acetoxyvinylnaphthalene is used instead of hydroxystyrene or hydroxyvinylnaphthalene, and after polymerization, the acetoxy group is removed by alkali hydrolysis. For protection, a hydroxystyrene unit or a hydroxyvinylnaphthalene unit may be used. Ammonia water, triethylamine and the like can be used as the base at the time of alkali hydrolysis. The reaction temperature is preferably -20 to 100C, more preferably 0 to 60C, and the reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 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 a repeating unit b1, b2, 0 <a <1.0, 0 ≦ b1 <1.0, 0 ≦ b2 <1.0, 0 <b1 + b2 <1.0, 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 proportion of the repeating unit c is 0 ≦ c ≦ 0.9, but when the repeating unit c is contained, it is preferably 0 <c ≦ 0.9 and 0.2 ≦ a + b + c ≦ 1.0. Here, when the repeating unit b is a repeating unit b1 or 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.

  The proportion of the repeating units d1 to d3 is 0 ≦ d1 ≦ 0.5, 0 ≦ d2 ≦ 0.5, 0 ≦ d3 ≦ 0.5, and 0 ≦ d1 + d2 + d3 ≦ 0.5. If it is 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, although 0.2 ≦ a + b1 + b2 + c + d1 + d2 + d3 ≦ 1.0, it is particularly preferable that 0.4 ≦ a + b1 + b2 + c + d1 + d2 + d3 ≦ 1.0.

  The proportions of the repeating units e1 to e5 are 0 ≦ e1 ≦ 0.5, 0 ≦ e2 ≦ 0.5, 0 ≦ e3 ≦ 0.5, 0 ≦ e4 ≦ 0.5, 0 ≦ e5 ≦ 0.5. , 0 ≦ e1 + e2 + e3 + e4 + e5 ≦ 0.5, but when including the repeating units e1 to e5, 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 proportion 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.

  Polymer A has a weight average molecular weight (Mw) of 1,000 to 500,000, preferably 2,000 to 30,000. When the Mw is 1,000 or more, the resist material has excellent heat resistance, and when the Mw is 500,000 or less, the alkali solubility is good, and there is no possibility that a footing phenomenon occurs after pattern formation. Note that Mw is a measured value in terms of polystyrene by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent.

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

  In the resist material of the present invention, the base resin may be one containing one kind of polymer A, one blended with two or more kinds of polymers having different composition ratios, molecular weight distributions, molecular weights, etc., a polymer containing neither polymer A nor repeating unit a. B may be blended.

[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 a compound that generates an acid in response to actinic rays or radiation (photoacid generator).

  The photoacid generator may be any compound as long as it is a compound that 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 the photoacid generator, those represented by the following formula (1) can also be suitably used.

In the 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 linear, branched or cyclic monovalent hydrocarbon group having 1 to 40 carbon atoms which may contain a fluorine atom or a hetero atom.

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

In the formula (1A ′), R ¹⁰⁴ represents a hydrogen atom or a trifluoromethyl group, and is 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 the hetero atom, an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom and the like are preferable, and an oxygen atom is more preferable. As the monovalent hydrocarbon group, a group having 6 to 30 carbon atoms is 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 Tyl 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 and the like. In addition, some of the hydrogen atoms in these groups may be substituted with a hetero atom-containing group such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, or between some carbon atoms in these groups. A hetero atom-containing group such as an oxygen atom, a sulfur atom and a nitrogen atom may be interposed, and as a result, a hydroxy group, a cyano group, a carbonyl group, an ether group, an ester group, a sulfonic ester group, a carbonate group, a lactone ring , A sultone ring, a carboxylic anhydride, a haloalkyl group, or the like.

  Regarding the synthesis of a sulfonium salt containing an anion represented by the formula (1A ′), JP-A-2007-145797, JP-A-2008-106045, JP-A-2009-7327, and JP-A-2009-258695 Etc. Further, sulfonium salts described in JP-A-2010-215608, JP-A-2012-41320, JP-A-2012-106986, JP-A-2012-153644 and the like are also preferably used.

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

In the formula (1B), R ^fb1 and R ^fb2 each independently represent a linear, branched or cyclic monovalent hydrocarbon group having 1 to 40 carbon atoms which may contain a fluorine atom or a hetero atom. Represent. Examples of the monovalent hydrocarbon group include the same groups as those described in the description of R ¹⁰⁵ . R ^fb1 and R ^fb2 are preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. Further, R ^fb1 and R ^fb2 may be bonded to each other to form a ring together with the group to which they are bonded (—CF ₂ —SO ₂ —N ^—— SO ₂ —CF ₂ —). ^The group obtained by bonding ^fb1 and ^Rfb2 to each other is preferably a fluorinated ethylene group or a fluorinated propylene group.

In the formula (1C), R ^fc1 , R ^fc2 and R ^fc3 each independently represent a linear, branched or cyclic monovalent carbon 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 groups as those described in the description of 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 the group to which they are bonded (—CF ₂ —SO ₂ —C ^—— SO ₂ —CF ₂ —). ^The group obtained by bonding ^fc1 and ^Rfc2 to each other is preferably a fluorinated ethylene group or a fluorinated propylene group.

In the 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 groups as those described in the description of R ¹⁰⁵ .

  The synthesis of the sulfonium salt containing the 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. In the following formula, Ph represents a phenyl group.

  The photoacid generator containing an anion represented by the formula (1D) has no fluorine at the α-position of the sulfo group but has two trifluoromethyl groups at the β-position. As a result, it has sufficient acidity to cleave acid labile groups in the resist polymer. Therefore, it can be used as a photoacid generator.

Further, as the photoacid generator, those represented by the following formula (2) can also be suitably used.

In the formula (2), R ²⁰¹ and R ²⁰² each independently represent 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 a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an s-butyl group, a t-butyl group, an n-pentyl group, a t-pentyl group, and an n-hexyl group. , N-octyl, n-nonyl, n-decyl, cyclopentyl, cyclohexyl, 2-ethylhexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl , Norbornyl, oxanorbornyl, tricyclo [5.2.1.0 ^2,6 ] decanyl, adamantyl, phenyl, naphthyl, anthracenyl and the like. In addition, some of the hydrogen atoms of these groups may be substituted with a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, or some of the 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 sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, It may contain 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, 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; saturated cyclic divalent hydrocarbon groups such as cyclopentanediyl group, cyclohexanediyl group, norbornanediyl group and adamantanediyl group; unsaturated cyclic groups such as phenylene group and naphthylene group Valent hydrocarbon group, and the like. In addition, some of the hydrogen atoms in these groups may be substituted with an alkyl group such as a methyl group, an ethyl group, a propyl group, an n-butyl group, and a t-butyl group. In addition, some of the hydrogen atoms in these groups may be substituted with a hetero atom-containing group such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, or between some carbon atoms in these groups. A hetero atom-containing group such as an oxygen atom, a sulfur atom and a nitrogen atom may be interposed, and as a result, a hydroxy group, a cyano group, a carbonyl group, an ether group, an ester group, a sulfonic ester group, a carbonate group, a lactone ring , A sultone ring, a carboxylic anhydride, a haloalkyl group, or the like. The hetero atom is preferably an oxygen atom.

As the photoacid generator represented by the formula (2), a photoacid generator represented by the following formula (2 ′) is preferable.

Wherein (2 '), L ^A is as defined 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 groups as those described in the description of R ¹⁰⁵ . x and y each independently represent an integer of 0 to 5; 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, 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 preferred because of their low acid diffusion and excellent solubility in resist solvents. Further, those containing an anion represented by the formula (2 ′) have extremely low acid diffusion, and are particularly preferable.

  The amount of the acid generator is preferably 0.01 to 100 parts by mass, more preferably 0.1 to 80 parts by mass, based on 100 parts by mass of the base resin. The acid generators can be used alone or in combination of two or more.

[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 and 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, and 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; Can be These solvents can be used alone or in combination of two or more.

  The amount of the organic solvent is preferably 50 to 10,000 parts by mass, more preferably 100 to 5,000 parts by mass, based on 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 controlling agent, a surfactant, an acetylene alcohol, and the like.

  By incorporating a basic compound into the resist material, for example, the diffusion rate of acid 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. The amount of the basic compound is preferably from 0 to 100 parts by mass, more preferably from 0.001 to 50 parts by mass, based on 100 parts by mass of the base resin.

  By adding a surfactant to the resist material, the coatability 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. The amount of the surfactant is preferably 0 to 10 parts by mass, more preferably 0.0001 to 5 parts by mass, based on 100 parts by mass of the base resin.

  By adding a dissolution controlling agent to the resist material, the difference in dissolution rate between the exposed and unexposed portions can be further increased, and the resolution can be further improved. Examples of the dissolution controlling agent include those described in paragraphs [0155] to [0178] of JP-A-2008-122932. The amount of the dissolution controlling agent is preferably from 0 to 50 parts by mass, more preferably from 0 to 40 parts by mass, based on 100 parts by mass of the base resin.

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

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

（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。） Further, the resist material of the present invention contains, as a quencher, a sulfonic acid in which the α-position represented by the following formula (3) is not fluorinated or an onium salt of a carboxylic acid represented by the following formula (4). May be.

(Wherein, R ¹⁵¹ , R ¹⁵² and R ¹⁵³ each independently represent a hydrogen atom, a halogen atom excluding a fluorine atom, or a linear, branched or branched C 1-40 carbon atom which may contain a hetero atom. It 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. M ⁺ represents an onium cation.)

  The onium salt of sulfonic acid in which the α-position is not fluorinated is described in detail in JP-A-2008-158339. Examples of the photoacid generator that generates a sulfonic acid in which the α-position is not fluorinated include compounds described in paragraphs [0019] to [0036] of JP-A-2010-155824 and JP-A-2010-215608. Examples include the compounds described in paragraphs [0047] to [0082]. The onium salt of a carboxylic acid is described in detail in Japanese Patent No. 399,462.

  The anion in the formula (3) or (4) is a conjugate base of a weak acid. The term "weak acid" as used herein means an acidity at which the acid labile group of the acid labile group-containing unit used in the base resin cannot be deprotected. When the onium salt represented by the formula (3) or (4) is used in combination with an onium salt-type photoacid generator having a conjugate base of a strong acid such as sulfonic acid in which the α-position is fluorinated as a counter anion. Acts as a quencher.

  That is, when an onium salt that generates a strong acid such as sulfonic acid in which the α-position is fluorinated is mixed with an onium salt that generates a weak acid such as sulfonic acid or carboxylic acid that is not substituted with fluorine. When a strong acid generated from a photoacid generator by high energy ray irradiation collides with an unreacted onium salt having a weak acid anion, the 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 for 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 in which the α-position is not fluorinated have photodegradability, so that the quenching ability of a portion having a high light intensity is reduced and the α-position is fluorinated. The concentration of sulfonic acid, imido acid or methide acid increases. As a result, it is possible to form a pattern with good dimensional 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, as described above, the strong acid generated by irradiation with high energy rays can be exchanged for a weak acid, but the weak acid generated by irradiation with high energy rays can be used. 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 tends to form an ion pair with the anion of the stronger acid.

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

Examples of the onium salt of a sulfonic acid and the onium salt of a carboxylic acid in which the α-position is not fluorinated include an onium salt of a sulfonic acid represented by the following formula (3 ′) and a The sulfonium salts of the carboxylic acids obtained 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 therebetween. 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 represent a hydrogen atom or a trifluoromethyl group. R ²⁵⁷ and R ²⁵⁸ each independently represent a hydrogen atom, a fluorine atom or a trifluoromethyl group. R ²⁵⁹ represents a linear, branched or cyclic monovalent hydrocarbon group having 1 to 35 carbon atoms which may contain a hydrogen atom, a hydroxy group, or a hetero atom, or a substituted or unsubstituted 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 represent an integer of 0 to 5.

  When such an onium salt is used as a quencher, it can be used alone or in combination of two or more. The compounding amount is preferably 0 to 50 parts by mass, more preferably 0.001 to 50 parts by mass, and still more preferably 0.01 to 20 parts by mass with respect to 100 parts by mass of the base resin. By blending such a quencher in the above range, in addition to the ease of adjusting the resist sensitivity, the diffusion rate of acid in the resist film is suppressed, the resolution is improved, and the change in sensitivity after exposure is reduced. It is possible to reduce the dependence on the substrate and the environment, and to improve the exposure margin and the pattern profile. The addition of such a quencher can also improve the substrate adhesion.

  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 for immersion lithography without using a top coat. As the water repellency improver, a polymer compound containing a fluorinated alkyl group, a polymer compound containing a 1,1,1,1,3,3,3-hexafluoro-2-propanol residue having a specific structure, and the like are preferable. Japanese Patent Application Laid-Open No. 2007-297590, Japanese Patent Application Laid-Open No. 2008-111103, and the like. The water repellency improver needs to be dissolved in an organic solvent developer. The aforementioned water repellent improver having a 1,1,1,3,3,3-hexafluoro-2-propanol residue has good solubility in a developing solution. As a water repellency enhancer, a polymer compound obtained by copolymerizing an amino group or an amine salt as a repeating unit has a high effect of preventing evaporation of an acid in PEB and preventing poor opening of a hole pattern after development. When a water repellency improver is included, the amount is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, based on 100 parts by mass of the base resin of the resist material.

  In a base resin containing the polymer A, an acid generator, an organic solvent, a dissolution controlling agent, a basic compound, a surfactant and the like are appropriately combined according to the purpose to form a resist material. Since the dissolution rate of the polymer A in the developing solution is accelerated by the catalytic reaction, a highly sensitive resist material can be obtained. The resist material of the present invention has a higher dissolution contrast and resolution of a resist film obtained therefrom, has an exposure allowance, has excellent process adaptability, and has a better pattern shape after exposure, but has a better etching resistance. In particular, since the acid diffusion can be suppressed, the dimensional difference between the densities is small. From these, the practicability is high, and it is very effective as a resist material for VLSI. In particular, when an acid generator is blended into a chemically amplified resist material utilizing an acid-catalyzed reaction, the material can be made more sensitive, and various characteristics become more excellent, which is extremely useful. .

[Pattern forming 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, an organic antireflection film, etc.) or a substrate for manufacturing a mask circuit (Cr, CrO). , CrON, MoSi ₂ , SiO _2, etc.) by a suitable coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, etc. so that the coating thickness becomes 0.1 to 2.0 μm. Apply to. This is prebaked on a hot plate, preferably 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 alkaline developer. During development, the protective film is peeled off together with the formation of the resist pattern. The protective film has a function to reduce outgas from the resist film, a function as a filter to cut out-of-band (OOB) of a wavelength of 140 to 300 nm other than 13.5 nm generated from the EUV laser, and a shape of the resist due to environmental influences. Has the function of preventing the head from becoming thin and causing a decrease in the film thickness. Next, the target pattern is exposed through a predetermined mask or directly by 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 radiations. 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 performed on a hot plate, preferably at 60 to 150 ° C for 10 seconds to 30 minutes, more preferably at 80 to 120 ° C for 30 seconds to 20 minutes.

  Furthermore, 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 a developing solution of an alkaline aqueous solution 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. Thereby, when the polymer A contains the repeating units b1 and / or b2, the portion irradiated with light dissolves in the developing solution, the portion not irradiated does not dissolve, 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-ray, soft X-ray, γ-ray, and synchrotron radiation among high energy rays.

  TEAH, TPAH, TBAH, and the like having a longer alkyl chain than TMAH, which is generally widely used, have an 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 a TMAH developer, a 2.38 mass% TMAH aqueous solution is most widely used. This corresponds to 0.26 N, and it is preferable that aqueous solutions such as TEAH, TPAH, and TBAH have the same normality. The masses of TEAH, TPAH and TBAH which are 0.26N are 3.84% by mass, 5.31% by mass and 6.78% by mass, respectively.

  In a pattern of 32 nm or less resolved by EB or EUV, a phenomenon occurs in which lines are distorted, lines are stuck together, or stuck lines fall. This is considered to be because the lines swelled and swelled in the developing solution are stuck together. The swollen line is soft like a sponge containing a developing solution, and thus easily collapses due to the stress of rinsing. The developer having a longer alkyl chain has an effect of preventing swelling and pattern collapse.

  When the polymer A contains the repeating units b1 and / or b2, a negative pattern can be obtained by organic solvent development. Examples of the developer include 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutylketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, Isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, methyl propionate, ethyl propionate Ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate Methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, 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 the development, rinsing is performed. As the rinsing liquid, a solvent that is mixed with the developer and does not dissolve the resist film is preferable. As such a solvent, an alcohol having 3 to 10 carbon atoms, an ether compound having 8 to 12 carbon atoms, an alkane, an alkene, an alkyne or an aromatic solvent having 6 to 12 carbon atoms is preferably used.

  Specifically, 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-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 Tertanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pent Tanol, cyclohexanol, 1-octanol and the like can be mentioned.

  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. Ether, di-n-hexyl ether and the like.

  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, cyclononane, and the like. Can be Alkenes having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene and the like. Alkynes having 6 to 12 carbon atoms include hexine, heptin, octin and the like.

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

  Hereinafter, the present invention will be specifically described with reference to Synthesis Examples, Comparative Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited to the following Examples.

[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 methacrylic acid chloride was added under ice cooling. 4 g were added dropwise. After stirring at room temperature for 5 hours, water was added to stop the reaction. After ordinary aqueous post-treatment, purification was carried out 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 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. The monomers 3 and 4 and the PAG monomers 1 and 2 used in the following synthesis examples are as follows.

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 a solvent Of THF was added. The reaction vessel was cooled to -70 ° C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After the temperature was raised to room temperature, 1.2 g of AIBN was added as a polymerization initiator, and the temperature was raised to 60 ° C., followed by a reaction for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered and dried at 60 ° C. under reduced pressure 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: 30.30
Mw = 7,500
Mw / Mn = 1.59

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 under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After the temperature was raised to room temperature, 1.2 g of AIBN was added as a polymerization initiator, and the temperature was raised to 60 ° C., followed by a reaction for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered and dried at 60 ° C. under reduced pressure 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 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 under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After the temperature was raised to room temperature, 1.2 g of AIBN was added as a polymerization initiator, and the temperature was raised to 60 ° C., followed by a 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- (adamantan-1-yl) -1-methylethyl 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 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 under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After the temperature was raised to room temperature, 1.2 g of AIBN was added as a polymerization initiator, and the temperature was raised to 60 ° C., followed by a reaction for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered and dried at 60 ° C. under reduced pressure 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 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 under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After the temperature was raised to room temperature, 1.2 g of AIBN was added as a polymerization initiator, and the temperature was raised to 60 ° C., followed by a reaction for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered and dried at 60 ° C. under reduced pressure 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 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 Synthetic Example 2 Synthesis of Comparative Polymer 2 Comparative polymer 2 was synthesized in the same manner as in Synthetic 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 instead of Monomer 1.
・ Copolymer composition ratio (molar ratio)
1- (adamantan-1-yl) -1-methylethyl 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] Evaluation of ArF exposure patterning [Examples 1-1 to 1-3, Comparative Examples 1-1 to 1-2]
A solution prepared by dissolving each component having the composition shown in Table 1 in a solvent in which 100 ppm of a surfactant FC-4430 manufactured by Sumitomo 3M Ltd. was dissolved was filtered through a 0.2 μm filter to obtain 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 materials (R-1 to R-5) were coated on a silicon wafer with a spin-on carbon film ODL-101 (carbon content: 80% by mass) of 160 nm by a silicon-containing spin-on. A hard mask SHB-A940 (having a silicon content of 43% by mass) is spin-coated on a substrate for a tri-layer process having a 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 formed.
ArF excimer laser immersion scanner (Nikon Corporation, NSR-610C, NA 1.30, σ 0.98 / 0.78, cross pole aperture 20 degrees, Azimuthally polarized illumination, 6% halftone phase shift mask, wafer size Using a grid-shaped mask having a pitch of 90 nm and a line width of 30 nm) while changing the exposure amount. After the exposure, PEB was performed for 60 seconds at the temperature shown in Table 2, and the developing solution shown in Table 2 was passed through a developing nozzle. Was discharged while rotating at 30 rpm for 3 seconds, followed by static paddle development for 27 seconds and spin drying to obtain a negative pattern.

  The dimensions of 50 locations of the hole pattern where the image of the solvent development was inverted were measured with TDSEM (CG-4000) manufactured by Hitachi High-Technologies Corporation, and the dimensional variation of 3σ was determined. The cross-sectional shape of the hole pattern was observed with an electron microscope S-4300 manufactured by Hitachi High-Technologies Corporation. Table 2 shows the results.

  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 a surfactant FC-4430 manufactured by Sumitomo 3M Ltd. was dissolved was filtered through a 0.2 μm filter to obtain 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

A clean track Mark 5 (manufactured by Tokyo Electron Ltd.) was used on a Si substrate obtained by treating the prepared resist materials (R-6 to R-8) with hexamethyldisilazane (HMDS) vapor prime having a diameter of 6 inches. Spin coating was performed and prebaked on a hot plate at 110 ° C. for 60 seconds to form a resist film having a thickness of 100 nm. Using an HL-800D manufactured by Hitachi, Ltd., drawing in a vacuum chamber was performed at an HV voltage of 50 kV.
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% by mass TMAH aqueous solution to obtain a positive pattern. 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 defined as the resolving power, and the edge roughness (LWR) of 100 nm LS was measured by SEM. Table 4 shows the results.

Claims (8)

A resist material comprising a base resin containing a polymer having 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. And
A resist material, 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 .

(In the formula, R ¹ represents a hydrogen atom or a methyl group. R ² represents a hydrogen atom, a linear or branched or cyclic alkyl group having 1 to 8 carbon atoms, a linear alkyl group 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, or an ester group or an ether group. Or a linking group having a carbon number of 1 to 12 containing a lactone ring. A represents a positive number satisfying 0 <a <1.0.) Repeating units containing groups polarity by acid changes may resist material according to claim 1 wherein is derived from the monomer represented by the following formula.

(In the formula, R ⁹ represents a hydrogen atom or a methyl group.) The polymer further comprises 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 ester group, a cyano group, an amide group, and -O- 3. 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 any one of claims 1 to 3 , wherein the polymer further contains at least one repeating unit selected from the following formulas (d1) to (d3).

(Wherein 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 - represents, Y ⁰ represents -O- or -NH-, R ^a is a carbonyl group, an ester group, which may contain an ether group or hydroxy group, 1 carbon atoms A linear, branched or cyclic alkylene group having 6 or a linear, branched or cyclic alkenylene group having 2 to 6 carbon atoms, or a phenylene group, represented by R ²² , R ²³ , R ²⁵ , R ²⁶ , R ²⁷ , R ²⁹ , R ³⁰ and R ³¹ each independently represent 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, and a hydroxy group. Or an aryl group having 6 to 12 carbon atoms, an aryl group having 7 to 20 carbon atoms. Represents a aralkyl group or a mercaptophenyl group, Z ¹ represents a single bond, or a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms which may contain an ether group, an ester group or a lactone ring; Represents a linear, branched or cyclic alkenylene group having 2 to 12 carbon atoms or an arylene group having 6 to 10 carbon atoms, and Z ² represents a single bond, a methylene group, an ethylene group, a phenylene group, or a fluorinated group. phenylene, -O-R ³² -, or ^{-C (= O) -Z 3 -R} 32 - represents, Z ³ represents -O- or -NH-, R ³² is a carbonyl group, 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.) The resist material according to any one of claims 1 to 4 , further comprising an acid generator and an organic solvent. Furthermore, a basic compound and / or the resist material of any one of claims 1 to 5 comprising a surfactant. A step of applying the resist composition of any one of claims onto a substrate according to claim 1 to 6, after heat treatment, exposing the resist coating to high-energy radiation, a pattern forming method comprising a step of developing with a developer . 8. The pattern forming method according to claim 7 , wherein the high energy ray is an i-line, a KrF excimer laser, an ArF excimer laser, an electron beam, or extreme ultraviolet light having a wavelength in the range of 3 to 15 nm.