WO2017188297A1

WO2017188297A1 - Resist composition and method for producing device using same

Info

Publication number: WO2017188297A1
Application number: PCT/JP2017/016486
Authority: WO
Inventors: 智至榎本; 優介菅
Original assignee: 東洋合成工業株式会社
Priority date: 2016-04-28
Filing date: 2017-04-26
Publication date: 2017-11-02
Also published as: TW201807491A; JPWO2017188297A1; KR20190004300A; JP6827037B2

Abstract

Provided is a resist composition that improves acid generation efficiency and is used to produce a photoresist having high sensitivity, high resolution, and high LWR properties. The present invention relates to a compound represented by general formula (1). (1) (In formula (1): Ar¹ and Ar² independently represent a phenylene group optionally having a substituent; R¹ represents a member selected from the group consisting of a thioalkoxy phenyl group, an arylthio group, and a thioalkoxy group optionally having a substituent; X represents a member selected from the group consisting of a sulfur atom, an oxygen atom, and a direct bond; R² represents either an aryl group or an alkyl group optionally having a substituent; each Y independently represents either an oxygen atom or a sulfur atom; R³ and R⁴ independently represent a linear, branched, or cyclic alkyl group optionally having a substituent; R³ and R⁴ are optionally bound to each other so as to form a ring structure together with two Y's in the formula; at least one of the carbon-carbon single bonds in the alkyl group included in R¹, R², R³, and R⁴ is optionally substituted with a carbon-carbon double bond or a carbon-carbon triple bond; and at least one of the methylene groups in the alkyl group included in R¹, R², R³, and R⁴ is optionally substituted with a heteroatom-containing divalent group.)

Description

Resist composition and device manufacturing method using the same

Some embodiments of the present invention relate to a composition that can be used for forming a resist pattern and a method for producing a device using the composition.

There is a high demand for higher density, higher integration, and higher speed in highly integrated circuit elements represented by semiconductor devices such as DRAMs. Accordingly, in various electronic device manufacturing fields, there is an increasing demand for the establishment of microfabrication technology on the order of half a micron, for example, the development of photolithography technology for forming fine patterns. In order to form a fine pattern in the photolithography technique, it is necessary to improve the resolution. Here, the resolution (R) of the reduction projection exposure apparatus is expressed by the Rayleigh equation R = k · λ / NA (where λ is the wavelength of exposure light, NA is the numerical aperture of the lens, and k is a process factor). Therefore, the resolution can be improved by shortening the wavelength λ of the active energy ray (exposure light) used in forming the resist pattern.

Chemically-amplified photoresists have been proposed as photoresists suitable for short wavelengths (Patent Documents 1 to 3). A feature of the chemically amplified photoresist is that an acid is generated from a photoacid generator as a component upon exposure to exposure light, and this acid causes an acid-catalyzed reaction with a resist compound or the like by heat treatment after exposure.
With the miniaturization of semiconductor devices, there is an increasing demand for EUV lithography technology that uses EUV (Extreme Ultra Violet) light having a wavelength of 13.5 nm as exposure light. However, the biggest drawback of EUV lithography is the lack of output of the EUV light source. For this reason, a highly sensitive photoresist is required, but there is a trade-off relationship among sensitivity, resolution, and LWR (Line Width Roughness). Therefore, there is a problem that increasing the sensitivity lowers resolution and increases roughness.

Japanese Patent Laid-Open No. 10-7650 JP 2003-327572 A JP 2008-7410 A

In order to solve the above problem, in the chemically amplified photoresist, how to improve the acid generation efficiency is one of the important issues for practical use.

One object of some embodiments of the present invention is to provide a resist composition that can improve the efficiency of acid generation. Another object of some aspects of the present invention is to provide a device manufacturing method using the resist composition that is suitably used as a photoresist composition that satisfies high sensitivity, high resolution, and high LWR characteristics. is there.

As a result of intensive investigations to solve the above problems, the present inventors, as a result, a photosensitizer precursor that can be dissociated by an acid to become a photosensitizer, a photoacid generator, a hydroxy group-containing compound, It has been found that the acid generation efficiency can be improved by using a resist composition containing an acid-reactive compound as a chemically amplified resist composition.
More specifically, in pattern formation using a chemically amplified photoresist containing a photoacid generator, a chemical composition comprising a photosensitizer precursor, a photoacid generator, a hydroxy group-containing compound, and an acid-reactive compound is chemically treated. Used as an amplification type photoresist composition, for example, the photosensitizer precursor is acid-dissociated with an acid generated from the photoacid generator by irradiation with a first active energy ray such as EUV light or electron beam (EB), and photosensitized. It was found that, when the photosensitizer is further irradiated with UV light or the like second, electron transfer to the photoacid generator occurs and the acid generation efficiency is improved.

One aspect of the present invention is a resist composition comprising a photosensitizer precursor represented by the following general formula (1), a photoacid generator, a hydroxy group-containing compound, and an acid-reactive compound. is there.

(In the above formula (1), Ar ¹ and Ar ² are each independently a phenylene group optionally having a substituent,
R ¹ is any one selected from the group consisting of an optionally substituted thioalkoxy group, arylthio group, and thioalkoxyphenyl group;
X is any selected from the group consisting of a sulfur atom, an oxygen atom and a direct bond;
R ² is either an alkyl group or an aryl group which may have a substituent,
Y is each independently one of an oxygen atom and a sulfur atom,
R ³ and R ⁴ are each independently a linear, branched or cyclic alkyl group which may have a substituent, and R ³ and R ⁴ are bonded to each other to form a compound It may form a ring structure with two Y in the inside,
At least one of the carbon-carbon single bonds in the alkyl group of R ¹ , R ² , R ³ and R ⁴ may be replaced with a carbon-carbon double bond or a carbon-carbon triple bond;
At least one of the methylene groups in the alkyl group of R ¹ , R ² , R ³ and R ⁴ may be replaced with a divalent heteroatom-containing group. )

The resist composition according to one embodiment of the present invention improves the acid generation efficiency of the photoacid generator and has high sensitivity, high resolution, and high LWR characteristics.

Hereinafter, the present invention will be described in detail.

<1> Photosensitizer precursor The photosensitizer precursor in one embodiment of the present invention is represented by the following general formula (1).

In the above formula (1), Ar ¹ and Ar ² are each independently a phenylene group optionally having a substituent,
R ¹ is any one selected from the group consisting of an optionally substituted thioalkoxy group, arylthio group, and thioalkoxyphenyl group;
X is any selected from the group consisting of a sulfur atom, an oxygen atom and a direct bond;
R ² is either an alkyl group or an aryl group which may have a substituent,
Y is each independently one of an oxygen atom and a sulfur atom,
R ³ and R ⁴ are each independently a linear, branched or cyclic alkyl group that may have a substituent,
R ³ and R ⁴ may be bonded to each other to form a ring structure with two Ys in the formula,
At least one of the carbon-carbon single bonds in the alkyl group of R ¹ , R ² , R ³ and R ⁴ may be replaced with a carbon-carbon double bond or a carbon-carbon triple bond;
At least one of the methylene groups in the alkyl group of R ¹ , R ² , R ³ and R ⁴ may be replaced with a divalent heteroatom-containing group.

In the photosensitizer precursor according to one embodiment of the present invention, the sum of Hammett substituent constants σ is preferably 0.2 or less.
In the present invention, the sum of Hammett substituent constants σ refers to each Ar ¹ , based on a group in which ^two quaternary carbons bonded to Y, Ar ¹ and Ar ² are bonded in the general formula (1). The sum of Hammett substituent constants σ of each substituent bonded to Ar ² .
Hammett substituent constant [sigma] is used in 1935 to discuss the effect of substituents on the reaction or equilibrium of benzene derivatives quantitatively. P. It is a value (total of σp value, σm value, and σo value) obtained by an empirical rule proposed by Hammett.
Among the substituent constants determined by Hammett's rule, the values of σp value and σm value are, for example, J. A. It is disclosed in detail in the Dean edition, “Lange's Handbook of Chemistry”, 12th edition, 1979 (McGraw-Hill) and “Areas of Chemistry”, 122, 96-103, 1979 (Nankodo).
Further, the σo value discussed regarding the influence of steric hindrance is, for example, Nuclear magnetic resonance studies of ortho-substituted phenols in dimethyl sulfoxide solutions. Electronic effects of orthostitutants J.E. Am. Chem. Soc. , 1969, 91 (2), pp 379-388, M .; Thomas and James G. It is disclosed in detail by Traynham.

The total sum of Hammett substituent constants σ of the photosensitizer precursor is preferably 0.2 or less, and more preferably −0.01 or less. Further, it is preferably −3.00 or more. In addition, the Hammett substituent constant σ of the substituent of Ar ¹ in the general formula (1) is preferably 1 or less. The Hammett substituent constant σ of the substituent of Ar ² in the general formula (1) is preferably 1 or less. The sum of Hammett substituent constant σ of the substituent of Ar ¹ and Hammett substituent constant σ of the substituent of Ar ² is 0.2 or less, so that the Hammett substituent constant σ of the photosensitizer precursor is reduced. Is less than 0.2.
When the sum of the Hammett substituent constants σ of the photosensitizer precursor is within the above range, the photoacid becomes when the photosensitizer precursor is acid-dissociated and becomes a photosensitizer. The acid generation efficiency of the generator can be improved. In order to make the sum of the Hammett substituent constant σ 0.2 or less, according to the Hammett substituent constant σ disclosed above, an electron-donating group or an electron-withdrawing substituent is appropriately selected for Ar ¹ and Ar ^2. And the Hammett substituent constant σ may be adjusted by introducing an electron donating group at an appropriate position.

Ar ¹ and Ar ² in the above formula (1) are each a phenylene group, and each of them is a substituent other than R ¹ or —X—R ² (hereinafter, the substituents of Ar ¹ and Ar ² are referred to as “first It may be referred to as a “substituent”. Ar ¹ and Ar ² are preferably bonded directly or indirectly to form a ring from the viewpoint of synthesis.
Examples of the first substituent include an electron donating group. Specific examples of the electron donating group include an alkyl group, an alkoxy group, an alkoxyphenyl group, a thioalkoxy group, an arylthio group, and a thioalkoxyphenyl group. Can be mentioned. Examples of the first substituent include a long-chain alkoxy group having a polyethylene glycol chain (— (CH ₂ CH ₂ O) _n —). Further, when the first substituent is bonded to the para position of Ar ¹ or Ar ² , it may have a hydroxy group as the first substituent.

In the present invention, the substitution position such as “para-position” of Ar ¹ or Ar ² is the position relative to the group to which the two quaternary carbons bonded to Ar ¹ and Ar ^{2 in} the above formula (1) are bonded. Say. For not only the first substituent but also other groups, the criterion for the substitution position such as “para-position” is the position with respect to the group bonded to the quaternary carbon.
The alkyl group as the first substituent is not particularly limited, but includes methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, isopropyl group, t-butyl group, cyclohexyl group, adamantyl group, etc. Examples thereof include linear, branched and cyclic alkyl groups having 1 to 20 carbon atoms. The alkoxy group as the first substituent is not particularly limited, and examples thereof include an alkoxy group having 1 to 20 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group.
Examples of the thioalkoxy group, arylthio group and thioalkoxyphenyl group as the first substituent include the same thioalkoxy groups, arylthio groups and thioalkoxyphenyl groups of R ¹ described later.

When the first substituent is an alkoxy group, an alkoxyphenyl group, a thioalkoxy group, an arylthio group, or a thioalkoxyphenyl group, the first substituent is bonded to the ortho position and / or the para position of the phenylene group that is Ar ¹ and Ar ^2. Preferably it is. At that time, it is preferred that the total number of the first substituent group of the Ar ¹ and Ar ² is 3 or less.

R ¹ in the above formula (1) is any selected from the group consisting of a thioalkoxy group, an arylthio group and a thioalkoxyphenyl group which may have a substituent.
Specifically, the thioalkoxy group for R ¹ is preferably a thioalkoxy group having 1 to 20 carbon atoms such as a thiomethoxy group, a thioethoxy group, a thio n-propoxy group, or a thio n-butoxy group, and a thioalkoxy group having 1 to 12 carbon atoms. An alkoxy group is more preferable.
Specific examples of the arylthio group for R ¹ include a phenylthio group and a naphthylthio group.

Specific examples of the thioalkoxyphenyl group represented by R ¹ include a phenyl group to which a thioalkoxy group having 1 to 20 carbon atoms such as a thiomethoxyphenyl group, a thioethoxyphenyl group, a thiopropoxyphenyl group, or a thiobutoxyphenyl is bonded. More preferred is a phenyl group to which a thioalkoxy group having 1 to 12 carbon atoms is bonded. No particular restriction on the substitution position of thioalkoxy group attached to the phenylene group in R ^1, but it is the para position is preferred from the viewpoint of increasing the molar extinction coefficient of the electron-donating and 365 nm.
R ¹ is preferably bonded to the ortho or para position of the phenylene group that is Ar ¹ .

R ² in the above formula (1) is either an alkyl group or an aryl group which may have a substituent.
Examples of the alkyl group for R ² include a straight chain or branched chain having 1 to 20 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an isopropyl group, a t-butyl group, and a cyclohexyl group. And cyclic alkyl groups.
Examples of the aryl group for R ² include a phenyl group and a naphthyl group.

R ¹ and R ² in the above formula (1) may have a substituent, and as the substituent (hereinafter, the substituents of R ¹ and R ² are referred to as “second substituent”), Although it does not restrict | limit in particular, In addition to the said 1st substituent, a nitro group, a sulfonyl group, a carbonyl group, a hydroxy group, etc. are mentioned. In particular, when at least one of R ¹ and R ² is an aryl group and the aryl group has a second substituent, the second substituent is a nitro group, a sulfonyl group, a carbonyl group, a hydroxy group, or the like. This is preferable because the molar extinction coefficient of 365 nm increases.
As will be described later, a polymerized group introduced into R ¹ or R ² and polymerized therefrom may be used as a polymer imparted with a sensitizing action. That is, a polymer including a unit having a function of a photosensitizer precursor as a unit is also a photosensitizer precursor in one embodiment of the present invention, and the second substituent includes a polymer main chain. Also good. Examples of the polymerizable group include a (meth) acryloyloxy group, an epoxy group, and a vinyl group.
Note that “(meth) acryloyl” represents acryloyl and methacryloyl.

When X in the formula (1) is an oxygen atom or a sulfur atom, it is preferable that the X is an ortho position or a para position of Ar ² . When X is a direct bond, it is preferable that X is an ortho or para position of Ar ² .

At least one of the carbon-carbon single bonds in R ¹ , R ² , the alkyl group of the first substituent and the second substituent is replaced with a carbon-carbon double bond or a carbon-carbon triple bond. Also good. In addition, at least one of the methylene groups in the alkyl group of R ¹ , R ² , the first substituent and the second substituent may be replaced with a divalent heteroatom-containing group.
Examples of the divalent heteroatom-containing group include —O—, —CO—, —COO—, —OCO—, —O—CO—O—, —NHCO—, —CONH—, and —NH—CO—O—. , —O—CO—NH—, —NH—, —N (R) —, —N (Ar) —, —S—, —SO—, and —SO ₂ —. It is a divalent organic group. Further, it is preferable that R ¹ , R ² , the first substituent, and the second substituent do not have a continuous connection of heteroatoms such as —O—O— and —SS—.
R may be the same as the alkyl group exemplified as the first substituent.
Ar is the same as the aryl group for R ² .
The total number of carbon atoms of R ^{1 in} the above formula (1) is not particularly limited, and is preferably 1 to 20 carbon atoms regardless of the presence or absence of the substituent of R ¹ . The total carbon number of R ^{2 in} the above formula (1) is not particularly limited, and is preferably 1 to 20 in total, regardless of the presence or absence of the substituent of R ² .
When the photosensitizer precursor is a polymer, the total carbon number of R ¹ and R ² excluding the portion containing the polymer main chain that becomes the second substituent is preferably 1-20.
R ¹ , R ² , the first substituent and the second substituent may have an acid dissociable group. The acid-dissociable group may be any protecting group that is deprotected by the action of an acid, such as t-butoxycarbonyloxy group, methoxymethoxy group, ethoxymethoxy group, trimethylsilyloxy group, tetrahydropyranyloxy group, and 1- An ethoxyethoxy group etc. are mentioned. In the resist composition according to one embodiment of the present invention, the photosensitizer precursor has an acid-dissociable group, so that the solubility is changed by the action of an acid, and a solubility contrast is obtained in the exposed and unexposed areas. It is preferable because it is easily formed.

Y is each independently either an oxygen atom or a sulfur atom.
R ³ and R ⁴ are each independently a linear, branched or cyclic alkyl group which may have a substituent. As the alkyl group of R ³ and R ⁴ , a straight chain having 1 to 20 carbon atoms such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, isopropyl group, t-butyl group, cyclohexyl group, etc. Examples include branched and cyclic alkyl groups.
From the viewpoint of synthesis, R ³ and R ⁴ are preferably the same.
In the present invention, when R ³ and R ⁴ are the groups shown above, the photosensitizer precursor may be deprotected with an acid to have a carbonyl group.

R ³ and R ⁴ may be bonded to each other to form a ring structure with two Ys in the formula.
That is, the photosensitizer precursor in one embodiment of the present invention is preferably a cyclic acetal compound having a cyclic acetal protecting group represented by the following formula (2). In the following formula (2), —R ⁵ —R ⁶ — is preferably — (CH ₂ ) _n —, and n is an integer of 2 or more. Although n is not particularly limited as long as it is 2 or more, it is preferably 8 or less for ease of synthesis. Moreover, it is preferable that n is 3 or more from a viewpoint of the activation energy of the cyclic acetal protecting group mentioned later. R ⁵ and R ⁶ correspond to those in which R ³ and R ⁴ in the above formula (1) are bonded to each other to form a ring.

Generally, it is known that an acyclic acetal has a lower activation energy than a cyclic acetal, and a cyclic acetal compound has a high hydrolysis rate. Among cyclic acetal compounds, a 5-membered ring structure such as 1,3-dioxolane has high activation energy and is stable, whereas a 6-membered ring such as 1,3-dioxane structure and 1,3-dioxepane. Those having the above structure have low activation energy. The relative comparison value of the hydrolysis rate due to the difference in the structure of the cyclic acetal compound is described in, for example, Non-patent Document Green's PROTECTIVE GROUPS in ORGANIC SYNTHESIS Fourth Edition, A John Wiley & Sons, Inc. , Publication, p 448-449.
The photosensitizer precursor in one embodiment of the present invention preferably has a low activation energy of the acetal protecting group. This is because the photosensitizer precursor is easily converted into a photosensitizer by the deprotection reaction of acetal. From the viewpoint of the activation energy of the acetal protecting group, R ³ and R ⁴ are preferably a linear, branched or cyclic alkyl group, and more preferably a linear alkyl group. In the above formula (2), in which R ³ and R ⁴ are bonded to each other to form a ring structure with two Y in the formula, —R ⁵ —R ⁶ — is a group in which n is 3 or more. (CH ₂ ) _n- is preferred.

R ³ and R ⁴ in the above formula (1) may have a substituent, and as the substituent (hereinafter, the substituents of R ³ and R ⁴ are referred to as “third substituent”), Although it does not restrict | limit, In addition to the said 2nd substituent, aryl groups, such as a phenyl group and a naphthyl group, etc. are mentioned.

At least one of the carbon-carbon single bonds in the alkyl group of R ³ , R ⁴ and the third substituent may be replaced with a carbon-carbon double bond or a carbon-carbon triple bond. In addition, at least one of methylene groups in the alkyl group of R ³ , R ⁴ and the third substituent may be replaced with the above divalent hetero atom-containing group.
The total carbon number of R ³ and R ^{4 in} the above formula (1) is not particularly limited, and the photosensitizer precursor may be a constituent component of a polymer. R ³ or R ⁴ preferably has a total carbon number of 1 to 20 regardless of the presence or absence of substituents. In the above formula (2), R ⁵ and R ⁶ may have the same third substituent as R ³ and R ⁴ . A polymer obtained by introducing a polymerizable group into R ³ or R ⁴ and polymerizing it may be used as a polymer imparted with a sensitizing action. That is, when the photosensitizer precursor in one embodiment of the present invention is a polymer including a unit having a photosensitizer precursor function as a unit, the third substituent is replaced with the third substituent. The substituent may contain a polymer main chain.
The total carbon number of R ³ and R ⁴ is preferably 1-20. When the photosensitizer precursor is a polymer, the total number of carbon atoms of R ³ and R ⁴ excluding the portion containing the polymer main chain serving as the third substituent is preferably 1-20.

The photosensitizer after acid treatment of the photosensitizer precursor, that is, the photosensitizer having a carbonyl group generated when the photosensitizer precursor is deprotected with an acid has a molar extinction coefficient at 365 nm of 1. It is preferable that it is 0.0 × 10 ⁵ cm ² / mol or more. A higher molar extinction coefficient at 365 nm is preferable, but a practical value is 1.0 × 10 ¹⁰ cm ² / mol or less. In order to make the molar extinction coefficient within the above range, the photosensitizer precursor has, for example, at least one selected from the group consisting of a thioalkoxy group, an arylthio group, and a thioalkoxyphenyl group, or an alkoxy group and A configuration having two or more aryloxy groups may be mentioned.
In the present invention, the molar extinction coefficient is at 365 nm in a chloroform solvent or acetonitrile solvent measured with a UV-VIS spectrophotometer using chloroform or acetonitrile as a solvent. The molar extinction coefficient of the photosensitizer having a carbonyl group in some embodiments of the present invention can be within the above range in either a chloroform solvent or an acetonitrile solvent.
Note that the photosensitizer precursor in one embodiment of the present invention is composed of -YR ³ and -YR ⁴ in the entire photosensitizer precursor from the viewpoint of ease of synthesis and light absorption characteristics. Or, there are no more than 4 groups selected from the group consisting of thioalkoxy groups other than —YR ³ —R ⁴ —Y—, arylthio groups, alkoxyphenyl groups, thioalkoxyphenyl groups, alkoxy groups, and aryloxy groups. It is preferable.

As a preferable example of the photosensitizer precursor represented by the above formula (1), for example, the following photosensitizer precursor can be exemplified. In the following examples, those shown in parentheses represent polymer units. The photosensitizer precursor in some embodiments of the present invention is not limited to this.

<2> Method for Synthesizing Photosensitizer Precursor A method for synthesizing a photosensitizer precursor in one embodiment of the present invention will be described. The present invention is not limited to this.
When the photosensitizer precursor in one embodiment of the present invention has a structure represented by the following formula (3), it can be synthesized, for example, by the following method. First, one selected from the group consisting of an alkoxybenzoyl chloride having an —X—R ² group, an alkylbenzoyl chloride, a thioalkoxybenzoyl chloride and a thioalkylbenzoyl chloride, and an alkyl group in which these alkyl groups are aryl groups, , And a halogenated benzene having an R ¹ group to give a benzophenone derivative by a Grignard reaction. Next, the benzophenone derivative is reacted with an alcohol and, if necessary, an ortho ester such as trialkyl orthoformate (R ³ , R ⁴ = alkyl group) as a dehydrating agent at 0 ° C. to reflux temperature for 1 to 120 hours. Thus, a derivative represented by the following formula (3) can be obtained.

When the photosensitizer precursor in one embodiment of the present invention has a structure represented by the following formula (4), the derivative represented by the above formula (3) and 1,3-propanediol obtained above are It can be obtained by reacting at 0 to 100 ° C. for 1 to 120 hours in the presence of an acid such as camphorsulfonic acid.

In the case where the photosensitizer precursor in one embodiment of the present invention has a structure represented by the following formula (5), the derivative represented by the above formula (3) obtained above and methanethiol are combined with boron trichloride or the like. It can be obtained by reacting at -78 ° C to 0 ° C for 1 to 120 hours in the presence of a Lewis acid.

When the photosensitizer precursor in one embodiment of the present invention has a structure represented by the following formula (6), the derivative represented by the above formula (3) obtained above and 3-mercapto-1-propanol It can be obtained by reacting at 0 to 100 ° C. for 1 to 120 hours in the presence of a Lewis acid such as zirconium chloride (IV).

In the case where the photosensitizer precursor in one embodiment of the present invention has a structure represented by the following formula (7), the derivative represented by the above formula (3) obtained above and methanethiol are combined with boron trichloride or the like. It can be obtained by reacting at 0 to 100 ° C. for 1 to 120 hours in the presence of a Lewis acid.

In the case where the photosensitizer precursor in one embodiment of the present invention has a structure represented by the following formula (8), the derivative represented by the above formula (3) obtained above and 1,3-propanedithiol are obtained. It can be obtained by reacting at 0 to 100 ° C. for 1 to 120 hours in the presence of a Lewis acid such as boron trichloride.

Since the photosensitizer precursor in one embodiment of the present invention has a specific structure, the acetalization reaction can be efficiently advanced. It is preferable that Ar ¹ and Ar ² do not have a ring structure through a divalent group and the quaternary carbon. The reason is that when Ar ¹ and Ar ² have a ring structure via a divalent group and the quaternary carbon, for example, when having a skeleton such as thioxanthone, it is difficult to efficiently advance the acetalization reaction. There is a case. Therefore, it is preferable in the synthesis that Ar ¹ and Ar ² do not have a ring structure directly or via a divalent group and the quaternary carbon.

<3> Photoacid generator The acid generator in one embodiment of the present invention is not particularly limited as long as it is usually used in a chemically amplified resist composition, and examples thereof include onium salt compounds, N-sulfonyloxyimides. Examples thereof include compounds, halogen-containing compounds, diazoketone compounds and the like. A photo-acid generator can be used individually by 1 type or in combination of 2 or more types. In consideration of the sensitivity of EUV and EB, the electron acceptability is preferably high, and the molar extinction coefficient with respect to 365 nm is preferably 1.0 × 10 ⁴ cm ² / mol or less.
Examples of the onium salt compounds include sulfonium salts, iodonium salts, phosphonium salts, diazonium salts, pyridinium salts, and the like. Examples of the sulfonium salt and iodonium salt include those described in WO2011 / 093139. Specific examples include photoacid generators represented by the following formula (9) or (10), but are not limited thereto.

R ^a COOR ^b SO ₃ ⁻ M ⁺ (9)
In the above formula (9), R ^a represents a monovalent organic group having 1 to 200 carbon atoms which may have a substituent, and R ^b represents that some hydrogen atoms are substituted with fluorine atoms. Or a good hydrocarbon group. M ⁺ represents a counter cation.

R ^a COOCH ₂ CH ₂ CFHCF ₂ SO ₃ ⁻ M ⁺ (10)
In the above formula (10), R ^a represents a monovalent organic group having 1 to 200 carbon atoms which may have a substituent. M ⁺ represents a counter cation.

The photo acid generator may be added to the resist composition as a low molecular weight component, or may be contained as a polymer unit. That is, the aspect contained in the polymer as a unit so that it may couple | bond with a polymer principal chain in any position of a photo-acid generator may be sufficient. For example, when the photoacid generator is a sulfonium salt, it is preferable to have a bond bonded to the polymer main chain directly or via a linking group, instead of one of the substituents in the sulfonium salt.

<4> Hydroxy group-containing compound The hydroxy group-containing compound according to one embodiment of the present invention is not particularly limited as long as hydrogen of a hydroxy group can be a hydrogen supply source when the photoacid generator is decomposed. By including the hydroxy group-containing compound in the resist composition, the acid generation efficiency from the photoacid generator is improved, and further, the ionization potential is increased as compared with the case where the hydroxy group is added to have no hydroxy group. Can be lowered.
Examples of hydroxy group-containing compounds include units derived from hydroxystyrene, hydroxyvinylnaphthalene, hydroxyphenyl acrylate, hydroxyphenyl methacrylate, hydroxy naphthyl acrylate, hydroxy norbornene acrylate, hydroxy norbornene methacrylate, hydroxy naphthyl methacrylate, hydroxy adamantane acrylate, hydroxy adamantane methacrylate, and the like. Polymers including: polyphenol compounds such as bisphenol and TrisP-PA (manufactured by Honshu Chemical Industry Co., Ltd.) calixarene; and the like. Among these, polymers containing units derived from hydroxystyrene, hydroxyvinylnaphthalene, hydroxyphenyl acrylate, hydroxyphenyl methacrylate, hydroxy naphthyl acrylate, hydroxy naphthyl methacrylate and the like are preferable. Examples of the hydroxyaryl group-containing compound include a polymer having a unit represented by the following formula (11).

In the above formula (11), Ar ³ represents an arylene group, R ⁷ represents a hydrogen atom or a hydrocarbon group, and L represents a carbonyloxy group or a direct bond.
The Ar ³ arylene group may further have a hydroxy group in addition to the hydroxy group disclosed in formula (11). The Ar ³ arylene group is preferably an arylene group having 6 to 14 carbon atoms which may have a substituent other than a hydroxy group, more preferably a phenylene group or a naphthylene group which may have a substituent. A phenylene group which may have a group is more preferable.
The hydrocarbon group for R ⁷ is preferably an alkyl group having 1 to 12 carbon atoms. R ⁷ is more preferably a hydrogen atom or a methyl group.

Preferred examples of the hydroxyaryl group-containing compound include polymers having units represented by the following formula, but are not limited thereto.

<5> Acid-reactive compound

Examples of the acid reaction compound include a compound having a protecting group that is deprotected by an acid, a compound having a polymerizable group that is polymerized by an acid, and a crosslinking agent having a crosslinking action by an acid.

A compound having a protecting group that is deprotected by an acid is, for example, a compound in which the solubility in a developer is changed when a protective group is deprotected by an acid to form a polar group when the composition is used as a resist composition. It is. For example, in the case of aqueous development using an alkaline developer or the like, it is insoluble in an alkaline developer, but the protective group is deprotected in the exposed area by an acid generated from the photoacid generator upon exposure, whereby an alkaline developer It is a compound that becomes soluble in.

In the present invention, the developer is not limited to an alkali developer, and may be a neutral developer or an organic solvent development. Therefore, when an organic solvent developer is used, the compound having a protecting group that is deprotected by an acid is deprotected in the exposed area by the acid generated from the photoacid generator upon exposure, and the organic solvent developer Is a compound whose solubility is reduced.

Examples of the polar group include a hydroxy group, a carboxy group, an amino group, and a sulfo group.
Specific examples of the protecting group to be deprotected with an acid include an ester group, an acetal group, a tetrahydropyranyl group, a siloxy group, and a benzyloxy group. As the compound having the protecting group, a compound having a styrene skeleton, a methacrylate or an acrylate skeleton pendant with these protecting groups is preferably used.
The compound having a protecting group to be deprotected with an acid may be a protecting group-containing low molecular weight compound or a protecting group-containing polymer. In the present invention, the low molecular weight compound has a weight average molecular weight of less than 1000, and the polymer has a weight average molecular weight of 1000 or more.

For example, when the composition is used as a resist composition, the compound having a polymerizable group that is polymerized with an acid is a compound whose solubility in a developer is changed by polymerization of the polymerizable group with an acid. For example, in the case of aqueous development, it is soluble in an aqueous developer, but the polymerizable group is polymerized in the exposed area by the acid generated from the photoacid generator upon exposure, and is soluble in the aqueous developer. It is a compound that decreases. Also in this case, an organic solvent developer may be used instead of the aqueous developer.

Examples of the polymerizable group that is polymerized with an acid include an epoxy group, a vinyloxy group, and an oxetanyl group. As the compound having a polymerizable group, a compound having a styrene skeleton, a methacrylate or an acrylate skeleton having these polymerizable groups is preferably used.
The compound having a polymerizable group that is polymerized with an acid may be a polymerizable low-molecular compound or a polymer.

For example, when the composition is used as a resist composition, the crosslinking agent having a crosslinking action with an acid is a compound that changes the solubility in a developer by crosslinking with an acid. For example, in the case of aqueous development, aqueous development It acts on a compound that is soluble in a liquid and reduces the solubility of the compound in an aqueous developer after crosslinking. Specifically, methylated melamine such as 2,4,6-tris [bis (methoxymethyl) amino] -1,3,5-triazine, 1,3,4,6-tetrakis (methoxymethyl) glycoluril, etc. And methylated urea. At this time, examples of the cross-linking partner compound include compounds having a phenolic hydroxyl group or a carboxy group.
The compound having a crosslinking action with an acid may be a polymerizable low molecular compound or a polymer.

<6> Composition Containing Photosensitizer Precursor One aspect of the present invention is the photosensitizer precursor, the photoacid generator, the hydroxy group-containing compound, and the acid-reactive compound. , A resist composition containing
In some embodiments of the present invention, the photosensitizer precursor is a photosensitizer in the above composition, wherein the photoacid generator generates an acid upon irradiation with active energy rays or the like, and is deprotected by the acid. obtain.
In the present invention, the photoacid generator generates an acid by the first irradiation using the first active energy ray, the photosensitizer precursor is deprotected by the acid to become a photosensitizer, and By performing the second irradiation using the second active energy having a wavelength at which the photosensitizer absorbs light, the photoacid generator is again applied only to the portion subjected to the first irradiation by the action of the photosensitizer. It is preferable that an acid can be generated. Thereby, while the said acid generates a photosensitizer further, the acid reaction compound which reacts with an acid can be made to react.

Specific examples of the resist composition according to one embodiment of the present invention include the following.
A resist composition comprising the photosensitizer precursor, a compound having a protecting group that is deprotected by the acid, and a photoacid generator; a compound having a polymerizable group that is polymerized by the photosensitizer precursor and the acid. A resist composition comprising: and a photoacid generator; a photosensitizer precursor; a crosslinking agent having a crosslinking action with an acid; a compound that reacts with the crosslinking agent to change solubility in a developer; And a resist composition containing a photoacid generator.
The photosensitizer precursor in one embodiment of the present invention can be preferably used as a sensitizer for positive and negative resist compositions.

The content of the photosensitizer precursor in the composition of one embodiment of the present invention is preferably 0.1 to 5 molar equivalents, and preferably 0.5 to 2.0 molar equivalents with respect to the photoacid generator. It is more preferable. When at least one of the photosensitizer precursor and the photoacid generator is a polymer, the mass is based on the polymer main chain.
The content of the photoacid generator in the resist composition of one embodiment of the present invention is preferably 1 to 50 parts by mass with respect to 100 parts by mass of the resist composition component excluding the photoacid generator. The amount is more preferably 30 parts by mass, and further preferably 1 to 15 parts by mass. By containing the photoacid generator in the composition within the above range, for example, even when the composition is used as a permanent film such as an insulating film such as a display body, the light transmittance can be increased. In the calculation of the content of the photoacid generator, the solvent is not included in 100 parts by mass of the resist composition component.

In the present invention, at least two selected from the group consisting of the photosensitizer precursor, the photoacid generator, the hydroxy group-containing compound, and the acid-reactive compound are included as units bonded to the same polymer. It is also preferable. Thereby, the distribution in the resist composition can be made uniform.
When the photosensitizer precursor is included as a unit of the same polymer together with at least one selected from the group consisting of the photoacid generator, the hydroxy group-containing compound and the acid-reactive compound, the photosensitizer The unit acting as an agent precursor is preferably 1 to 40 mol%, more preferably 10 to 35 mol%, and still more preferably 10 to 30 mol% in the total polymer unit.

When the photoacid generator is included as a unit of the same polymer together with at least one selected from the group consisting of the photosensitizer precursor, the hydroxy group-containing compound, and the acid-reactive compound, the photoacid generator The unit acting as an agent is preferably 1 to 40% by mole, more preferably 5 to 35% by mole, and still more preferably 5 to 30% by mole based on all units of the polymer.
When the hydroxy group-containing compound is contained as a unit of the same polymer together with at least one selected from the group consisting of the photosensitizer precursor, the photoacid generator and the acid-reactive compound, the hydroxy group-containing compound The unit acting as a compound is preferably from 3 to 90 mol%, more preferably from 5 to 80 mol%, more preferably from 7 to 70 mol% in the whole polymer unit for a positive resist composition for aqueous development. More preferably. For a negative resist composition for aqueous development, it is preferably 60 to 99 mol%, more preferably 70 to 98 mol%, and still more preferably 75 to 98 mol% in the total unit of the polymer.
When the acid-reactive compound is included as a unit of the same polymer together with at least one selected from the group consisting of the photosensitizer precursor, the photoacid generator, and the hydroxy group-containing compound, the photosensitization The unit acting as the agent precursor is preferably 3 to 40 mol%, more preferably 5 to 35 mol%, and still more preferably 7 to 30 mol% in the total polymer unit.

The polymer in one embodiment of the present invention preferably has a weight average molecular weight of 1,000 to 200,000, more preferably 2,000 to 50,000, and even more preferably 2,000 to 15,000. The polymer preferably has a dispersity (molecular weight distribution) (Mw / Mn) of 1.0 to 1.7, more preferably 1.0 to 1.2 from the viewpoint of sensitivity. The weight average molecular weight and dispersity of the polymer are defined as polystyrene converted values by GPC measurement.

In the composition of one embodiment of the present invention, in addition to the above components, as an optional component, an acid diffusion controller, a surfactant, an organic carboxylic acid, a solvent, a dissolution inhibitor, which are used in an ordinary resist composition, A stabilizer, a dye, and other sensitizers other than the photosensitizer precursor may be included in combination.
The acid diffusion control agent controls the diffusion phenomenon of the acid generated from the photoacid generator in the resist film, and has an effect of controlling an undesirable chemical reaction in the non-exposed region. Therefore, the storage stability of the resulting resist composition is improved, and the resolution as a resist is improved. At the same time, it is possible to suppress a change in the line width of the resist pattern due to fluctuations in the holding time from exposure to development, and a resist composition having excellent process stability can be obtained.
Examples of the acid diffusion controller include compounds having one, two, or three nitrogen atoms in the same molecule, amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, and the like. Further, as the acid diffusion controlling agent, a photodegradable base that is sensitized by exposure to generate a weak acid can also be used. Examples of the photodegradable base include onium salt compounds and iodonium salt compounds that lose acid diffusion controllability by being decomposed by exposure.
Specifically, Japanese Patent Nos. 3577743, 2001-215589, 2001-166476, 2008-102383, 2010-243773, 2011-37835, and 2012-173505. And the compounds described in the above.
The content of the acid diffusion controller is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 5 parts by mass, and more preferably 0.05 to 10 parts by mass with respect to 100 parts by mass of the resist composition component. More preferably, it is 3 parts by mass.

The surfactant is preferably used for improving the coating property. Examples of surfactants include nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene polyoxypropylene block copolymers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, etc. Agents, fluorosurfactants, organosiloxane polymers, and the like.
The content of the surfactant is preferably 0.0001 to 2 parts by mass, more preferably 0.0005 to 1 part by mass with respect to 100 parts by mass of the resist composition component.

Examples of the organic carboxylic acid include aliphatic carboxylic acid, alicyclic carboxylic acid, unsaturated aliphatic carboxylic acid, oxycarboxylic acid, alkoxycarboxylic acid, ketocarboxylic acid, benzoic acid derivative, phthalic acid, terephthalic acid, isophthalic acid, 2 -Naphthoic acid, 1-hydroxy-2-naphthoic acid, 2-hydroxy-3-naphthoic acid and the like. Aromatic organic carboxylic acids, such as benzoic acid and 1-hydroxy-2-naphthoic acid, among them, are less likely to volatilize from the resist film surface and contaminate the drawing chamber when the electron beam exposure is performed in vacuum. 2-hydroxy-3-naphthoic acid is preferred as the organic carboxylic acid.
The content of the organic carboxylic acid is preferably 0.01 to 10 parts by mass, more preferably 0.01 to 5 parts by mass, and still more preferably 0.01 to 3 parts by mass with respect to 100 parts by mass of the resist composition component. It is.

Examples of the solvent include ethylene glycol monoethyl ether acetate, cyclohexanone, 2-heptanone, propylene glycol monomethyl ether (PGME), propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether propionate, propylene glycol monoethyl ether acetate. Methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl β-methoxyisobutyrate, ethyl butyrate, propyl butyrate, methyl isobutyl ketone, ethyl acetate, isoamyl acetate, ethyl lactate, toluene, xylene, cyclohexyl acetate, diacetone alcohol N-methylpyrrolidone, N, N-dimethylformamide, γ-butyrolactone, N, N-dimethylacetami , Propylene carbonate, ethylene carbonate, etc. are preferable. These solvents are used alone or in combination.
The resist composition component is preferably dissolved in the solvent so that the solid content concentration is 1 to 40% by mass. More preferably, it is 1 to 30% by mass, and further preferably 3 to 20% by mass. By setting the solid content concentration in such a range, the above film thickness can be achieved.

In addition to the above, the resist composition of one embodiment of the present invention may contain a fluorine-containing water-repellent polymer. Although there is no restriction | limiting in particular as said fluorine-containing water-repellent polymer, The thing normally used for the immersion exposure process is mentioned, The one where a fluorine atom content rate is larger than the said polymer is preferable. Accordingly, when the resist film is formed using the resist composition, the fluorine-containing water-repellent polymer can be unevenly distributed on the resist film surface due to the water-repellent property of the fluorine-containing water-repellent polymer. .
The composition of one aspect of the present invention is obtained by mixing the components of the above composition, and the mixing method is not particularly limited.

The resist composition of one embodiment of the present invention may contain a ketone derivative represented by the following general formula (12) instead of the sensitizer precursor. The ketone derivative corresponds to one produced by hydrolysis of the sensitizer precursor by acid treatment. Each substituent in the following general formula (12) is the same as the substituent in the above general formula (1). Thereby, it can be used as a photosensitizer having a large absorption with a molar extinction coefficient at 365 nm of 1.0 × 10 ⁵ cm ² / mol or more without requiring a deprotection reaction with an acid. Therefore, it can be suitably used as a chemically amplified resist composition for UV, and can be suitably used for optical device applications that require particularly high visible light transmittance. In the case of a UV chemically amplified resist, even if the resist composition does not contain a hydroxy group-containing compound, the acid generation efficiency can be improved by including the ketone derivative.

<7> Device Manufacturing Method One embodiment of the present invention includes a step of applying the composition on a substrate to form a resist film (hereinafter also referred to as a “resist film forming step”), and a first step in the resist film. A step of irradiating active energy rays (hereinafter also referred to as “first irradiation step”) and a step of irradiating the resist film irradiated with the first active energy rays with second active energy rays (hereinafter referred to as “second irradiation”). And a step of developing the resist film irradiated with the second active energy ray to obtain a pattern (hereinafter also referred to as “pattern formation step”).

As described above, in the present invention, by performing the first irradiation with the first active energy ray, the photoacid generator generates an acid, and the photosensitizer precursor is deprotected by the acid to cause photosensitization. Become a sensitizer. Then, by performing the second irradiation with the second active energy ray having a wavelength at which the photosensitizer absorbs light, the photoacid generator is again applied only to the portion subjected to the first irradiation by the action of the photosensitizer. Is preferably capable of generating an acid. Thereby, while the said acid generates a photosensitizer further, the acid reaction compound which reacts with an acid can be made to react.
The first active energy ray used in the first irradiation may be a particle beam or an electromagnetic wave that can generate an acid when the photoacid generator contained in the composition is activated, such as a KrF excimer laser beam or an ArF excimer laser. Examples thereof include light, F ₂ excimer laser light, electron beam, UV, visible light, X-ray, ion beam, g-line, h-line, i-line, and EUV. Of these, electron beam, X-ray, EUV and the like are preferable.
As the second active energy rays used in the second irradiation, photosensitizer that produces by R ³ and R ⁴ of the photosensitizer precursor represented by the formula (1) is deprotected to absorb Any electromagnetic wave may be used as long as it has a wavelength. Examples of the electromagnetic wave include KrF excimer laser light, ArF excimer laser light, F ₂ excimer laser light, UV, visible light, g-line, h-line, and i-line. Is mentioned.
When the first active energy ray is an electromagnetic wave, the electromagnetic wave of the first active energy ray preferably has a shorter wavelength than the electromagnetic wave used as the second active energy ray.

Except for using the composition containing the photosensitizer precursor, a normal device manufacturing method may be followed.

One embodiment of the present invention includes a resist film formation step, a first irradiation step, a second irradiation step, and a pattern formation step using the above composition, and a substrate having a pattern before obtaining individualized chips. It may be a manufacturing method.

In one embodiment of the present invention, the resist film formed from the resist composition preferably has a thickness of 10 to 200 nm. The resist composition is applied onto the substrate by an appropriate application method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, and the like, and is performed at 60 to 150 ° C. for 1 to 20 minutes, preferably 80 to Pre-bake at 120 ° C. for 1 to 10 minutes to form a thin film. The thickness of this coating film is 10 to 200 nm, preferably 20 to 150 nm.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the following synthesis examples, the molar extinction coefficient after acid treatment of a compound, that is, the molar extinction coefficient at 365 nm of a benzophenone compound derivative obtained by deprotecting the compound was measured with a UV-VIS spectrophotometer (Hitachi Co., Ltd.). (U-3300) manufactured by Seisakusho, using chloroform or acetonitrile as a solvent.

Synthesis Example 1 Synthesis of 2,4-methoxy-4′-methylthiobenzophenone (sensitizer compound A1) 8.0 g of 4-bromothioanisole was dissolved in 32 g of tetrahydrofuran, and 1 mol / L methylmagnesium bromide was dissolved therein. 39 ml of THF solution is added dropwise at 5 ° C. or lower. After dropping, the mixture is stirred at 5 ° C. or lower for 30 minutes to obtain a THF solution of 4-methylthiophenylmagnesium bromide. To a solution of 8.8 g of 2,4-dimethoxybenzoyl chloride dissolved in 15 g of THF, a THF solution of 4-methylthiophenylmagnesium bromide is dropped at 10 ° C. or lower, and then stirred at 25 ° C. for 1 hour. After stirring, 50 g of a 10% by mass aqueous ammonium chloride solution is added at 20 ° C. or lower and the mixture is further stirred for 10 minutes, and the organic layer is extracted with 80 g of ethyl acetate. After washing with pure water, ethyl acetate and tetrahydrofuran are distilled off to obtain crude crystals. The crude crystals are recrystallized using 120 g of ethanol to obtain 7.6 g of 2,4-dimethoxy-4′-methylthiobenzophenone. The molar extinction coefficient at 365 nm in chloroform solvent is 1.1 × 10 ⁶ cm ² / mol.

Synthesis Example 2 Synthesis of (2,4-dimethoxy) phenyl- (4′-methylthio) phenyl-dimethoxymethane (Precursor Compound B1) 5.0 g of 2,4-dimethoxy-4′-methylthiobenzophenone and 47 mg of sulfuric acid 13.5 g of trimethyl orthoformate is dissolved in 12.5 g of methanol, and this is stirred at reflux temperature for 3 hours. Thereafter, the mixture is cooled to room temperature, and 50 g of a 5% by mass aqueous sodium hydrogen carbonate solution is added thereto, followed by further stirring for 10 minutes, and the precipitated crystals are filtered. The crystals are recovered, redissolved in 50 g of ethyl acetate and then washed with pure water. Thereafter, ethyl acetate is distilled off to obtain 4.0 g of (2,4-dimethoxy) phenyl- (4′-methylthio) phenyl-dimethoxymethane. The sum of Hammett substituent constants σ is −0.56.

(Synthesis Example 3) Synthesis of 4-fluoro-4′-methylthiobenzophenone 4-Fluorobenzoyl chloride was used in the same manner as in Synthesis Example 1 except that 4-fluorobenzoyl chloride was used instead of 2,4-dimethoxybenzoyl chloride. 7.4 g of -4'-methylthiobenzophenone are obtained.

(Synthesis Example 4) Synthesis of 4-methylthio-4′-phenylthiobenzophenone (sensitizer compound A2) 6.0 g of 4-fluoro-4′-methylthiobenzophenone obtained in Synthesis Example 3 was dissolved in 30 g of DMF, Add 3.2 g of thiophenol and 4.0 g of potassium carbonate and stir at 70 ° C. for 4 hours. After stirring, 90 g of pure water is added and the mixture is further stirred for 10 minutes, and the organic layer is extracted with 60 g of toluene. This is washed three times with pure water, and then toluene is distilled off to obtain crude crystals. The crude crystals are recrystallized using 40 g of ethanol to obtain 5.6 g of 4-methylthio-4′-phenylthiobenzophenone. The molar extinction coefficient at 365 nm in chloroform solvent is 2.6 × 10 ⁶ cm ² / mol.

Synthesis Example 5 Synthesis of (4-methylthio) phenyl- (4′-phenylthio) phenyl-dimethoxymethane (precursor compound B2) 4-methylthio-4 ′ instead of 2,4-dimethoxy-4′-methylthiobenzophenone By performing the same operation as in Synthesis Example 2 except that -phenylthiobenzophenone is used, 3.1 g of (4-methylthio) phenyl- (4′-phenylthio) phenyl-dimethoxymethane is obtained. The Hammett substituent constant is 0.2 or less.

Synthesis Example 6 Synthesis of (4-methylthio) phenyl- (4′-phenylthio) phenyl-diethoxymethane (Precursor Compound B3) (4-Methylthio) phenyl- (4′-phenylthio) obtained in Synthesis Example 5 5.0 g of phenyl-dimethoxymethane, 300 mg of camphorsulfonic acid and 4.3 g of triethyl orthoformate are dissolved in 32.5 g of dehydrated ethanol, and the mixture is stirred at 70 ° C. for 5 hours while distilling off methanol in the solution together with ethanol. . Thereafter, the mixture is cooled to room temperature, 50 g of a 5% by mass aqueous sodium hydrogen carbonate solution is added thereto, followed by extraction with 50 g of ethyl acetate and washing with pure water three times. Thereafter, ethyl acetate was distilled off, and purification was performed by column chromatography (ethyl acetate / cyclohexane = 5/95 (volume ratio)) to obtain (4-methylthio) phenyl- (4′-phenylthio) phenyl-diethoxymethane 4 .6 g is obtained. The sum total of Hammett substituent constants σ is 0.2 or less.

(Synthesis Example 7) Synthesis of 2- (4-methylthio) phenyl-2- (4′-phenylthio) phenyl-1,3-dioxolane (precursor compound B4) The above except that dehydrated ethylene glycol was used instead of dehydrated ethanol By performing the same operation as in Synthesis Example 6, 4.6 g of 2- (4-methylthio) phenyl-2- (4′-phenylthio) phenyl-1,3-dioxolane is obtained. The sum total of Hammett substituent constants σ is 0.2 or less.

Synthesis Example 8 Synthesis of 2-methoxy-4′-methylthiobenzophenone (sensitizer compound A3) The same procedure as in Synthesis Example 1 except that 2-methoxybenzoyl chloride was used instead of 2,4-dimethoxybenzoyl chloride To give 2-methoxy-4′-methylthiobenzophenone. The molar extinction coefficient at 365 nm in chloroform solvent is 1.0 × 10 ⁵ cm ² / mol or more.

Synthesis Example 9 Synthesis of (2-methoxy) phenyl- (4′-methylthio) phenyl-dimethoxymethane (precursor compound B5) 2-methoxy-4 ′ instead of 2,4-dimethoxy-4′-methylthiobenzophenone 2.7 g of 2- (2-methoxyphenyl) -2- (4′-methylthiophenyl) -dimethoxymethane is obtained by performing the same operation as in Synthesis Example 2 except that -methylthiobenzophenone is used. The sum of the Hammett substituent constant σ is −0.37.

Synthesis Example 10 Synthesis of 4- (4-methoxyphenyl) -4′-methylthiobenzophenone (sensitizer compound A4) 4- (4-methoxyphenyl) benzoyl chloride is used in place of 2,4-dimethoxybenzoyl chloride Except for the above, the same operation as in Synthesis Example 1 is carried out to obtain 5.2 g of 4- (4-methoxyphenyl) -4′-methylthiobenzophenone. The molar extinction coefficient at 365 nm in chloroform solvent is 1.0 × 10 ⁵ cm ² / mol or more.

(Synthesis Example 11) Synthesis of [4- (4-methoxy) phenyl] phenyl- (4′-methylthio) phenyldimethoxymethane (Precursor Compound B6) In place of 2,4-dimethoxy-4′-methylthiobenzophenone, 4- Except for using (4-methoxyphenyl) -4′-methylthiobenzophenone, the same procedure as in Synthesis Example 2 was performed to obtain (4-methoxyphenyl) -phenyl- (4′-methylthiophenyl) -dimethoxymethane as 4. 1 g is obtained. The sum of the Hammett substituent constant σ is −0.26.

Synthesis Example 12 Synthesis of 2-methylthio-4,4′-dimethoxybenzophenone (sensitizer compound A5) 4.6 g of 3-methylthioanisole and 4.9 g of aluminum chloride are dissolved in 15 g of dichloromethane. 4-methoxybenzoyl chloride 5.0g is dripped at this at 5 degrees C or less over 30 minutes. Then, after stirring at 5 ° C. for 2 hours, 15 g of pure water is added so as to be 25 ° C. or less, and further stirred for 10 minutes. The organic layer is separated and recovered and washed with pure water, dichloromethane is distilled off, and the resulting residue is produced by recrystallization using 70 g of ethanol, whereby 2-methylthio-4,4′-dimethoxybenzophenone. 6.5 g is obtained. The molar extinction coefficient at 365 nm in chloroform solvent is 1.0 × 10 ⁵ cm ² / mol or more.

Synthesis Example 13 Synthesis of (2-methylthio-4-methoxy) phenyl- (4′-methoxy) phenyldimethoxymethane (Precursor Compound B7) 2-methylthio instead of 2,4-dimethoxy-4′-methylthiobenzophenone 3.7 g of (2-methylthio-4-methoxy) phenyl- (4′-methoxy) phenyldimethoxymethane is obtained by performing the same operation as in Synthesis Example 2 except that -4,4′-dimethoxybenzophenone is used. The sum of Hammett substituent constants σ is −0.33.

Synthesis Example 14 Synthesis of 4- (2-vinyloxy) ethylthiobromobenzene 5.0 g of 4-bromothiophenol, 5.7 g of chloroethyl vinyl ether, and 7.3 g of potassium carbonate were dissolved in 20 g of acetone at a reflux temperature. Stir for 3 hours. Then, it cools to room temperature, 60 g of pure waters are added, and it stirs for 5 minutes. To this, 90 g of toluene is added for extraction, followed by separation washing with pure water. Thereafter, toluene is distilled off to obtain 6.4 g of 4- (2-vinyloxy) ethylthiobromobenzene.

(Synthesis Example 15) 4- (2-vinyloxy) ethylthio-2 ′, 4′-dimethoxybenzophenone)
4- (2-Vinyloxy) ethylthio-2 ′, 4′- is performed in the same manner as in Synthesis Example 1 except that 4- (2-vinyloxy) ethylthiobromobenzene is used instead of 4-bromothioanisole. 8.4 g of dimethoxybenzophenone) is obtained. The molar extinction coefficient at 365 nm in chloroform solvent is 1.0 × 10 ⁵ cm ² / mol or more.

Synthesis Example 16 Synthesis of 4- (2-hydroxy) ethylthio-2 ′, 4′-dimethoxybenzophenone 5.0 g of 4- (2-vinyloxy) ethylthio-2 ′, 4′-dimethoxybenzophenone and pure water 3. 3 g and 0.44 g of pyridinium-p-toluenesulfonic acid are added to 30 g of acetone and stirred at reflux temperature for 3 hours. After cooling to room temperature, 85 g of pure water is added and the mixture is stirred for 5 minutes and extracted with ethyl acetate. After separation and washing with pure water, ethyl acetate is distilled off to obtain 4.6 g of 4- (2-hydroxy) ethylthio-2 ′, 4′-dimethoxybenzophenone.

Synthesis Example 17 Synthesis of 4- (2-methacryloxy) ethylthio-2 ′, 4′-dimethoxybenzophenone (sensitizer compound A6) 4- (2-hydroxy) ethylthio-2 ′, 4′-dimethoxybenzophenone 5 g And 2.9 g of methacrylic anhydride are dissolved in 15 g of THF, and 1.9 g of triethylamine is added dropwise thereto in 30 minutes so that the temperature is 20 ° C. or lower. After dripping, after stirring at 25 degreeC for 3 hours, 40 g of pure waters are added, and also it stirs for 10 minutes. This is extracted with 50 g of ethyl acetate and separated and washed with pure water. Thereafter, ethyl acetate is distilled off to obtain 5.1 g of the desired 4- (2-methacryloxy) ethylthio-2 ′, 4′-dimethoxybenzophenone. The molar extinction coefficient at 365 nm in chloroform solvent is 1.1 × 10 ⁶ cm ² / mol.

Synthesis Example 18 Synthesis of 4-[(2-methacryloxy) ethylthio] -phenyl- (2 ′, 4′-dimethoxyphenyl) dimethoxymethane (precursor compound B8) 2,4-dimethoxy-4′-methylthiobenzophenone Instead of 4- (2-methacryloxy) ethylthio-2 ′, 4′-dimethoxybenzophenone, 4-[(2-methacryloxy) ethylthio] -phenyl was obtained in the same manner as in Synthesis Example 2 above. 2.6 g of-(2 ', 4'-dimethoxyphenyl) dimethoxymethane are obtained. The sum of Hammett substituent constants σ is −0.56.

Synthesis Example 19 Synthesis of 4- (4-hydroxyphenylthio) -4′-methylthiobenzophenone (sensitizer Compound A7) Same as Synthesis Example 4 except that 4-hydroxybenzenethiol was used instead of thiophenol By performing the operation, 5.8 g of 4- (4-hydroxyphenylthio) -4′-methylthiobenzophenone is obtained. The molar extinction coefficient at 365 nm in chloroform solvent is 3.01 × 10 ⁶ cm ² / mol. Moreover, the molar extinction coefficient of 365 nm with acetonitrile solvent is 1.73 × 10 ⁶ cm ² / mol.

Synthesis Example 20 Synthesis of 4- (4-hydroxyphenylthio) phenyl-4′-methylthiophenyl-dimethoxymethane (Precursor Compound B9) 4- (4 instead of 2,4-dimethoxy-4′-methylthiobenzophenone Except for using -hydroxyphenylthio) -4'-methylthiobenzophenone, 3.3 g of 4- (4-hydroxyphenylthio) phenyl-4'-methylthiophenyl-dimethoxymethane was obtained by performing the same operation as in Synthesis Example 2 above. obtain. The sum total of Hammett substituent constants σ is 0.2 or less.

Synthesis Example 21 Synthesis of 4,4′-di (4-hydroxyphenylthio) benzophenone (sensitizer Compound A8) 6.5 g of 4,4′-difluorobenzophenone was dissolved in 20 g of DMF, and 4-hydroxybenzene was dissolved therein. Add 11.3 g of thiol and 12.4 g of potassium carbonate and stir at 70 ° C. for 2 hours. After stirring, 90 g of pure water is added and the mixture is further stirred for 10 minutes to precipitate a solid. The precipitated solid is collected by filtration and vacuum dried to obtain crude crystals. The crude crystals are dispersed in 120 g of methylene chloride and stirred for 1 hour. After stirring, the solid is collected by filtration and dried in vacuo to obtain 12.0 g of 4,4′-di (4-hydroxyphenylthio) benzophenone. The molar extinction coefficient at 365 nm in acetonitrile solvent is 2.77 × 10 ⁶ cm ² / mol.

(Synthesis Example 21) Synthesis of bis [4- (4-hydroxyphenylthio) phenyl] -dimethoxymethane (precursor compound B10) 4,4′-di (instead of 2,4-dimethoxy-4′-methylthiobenzophenone) 3.0 g of bis [4- (4-hydroxyphenylthio) phenyl] -dimethoxymethane is obtained by performing the same operation as in Synthesis Example 2 except that 4-hydroxyphenylthio) benzophenone is used. The sum total of Hammett substituent constants σ is 0.2 or less.

Synthesis Example 22 Synthesis of 4- [4- (methoxymethoxy) phenylthio] phenyl-4′-methylthiophenyl-dimethoxymethane (precursor compound B11) 4- (4-hydroxyphenylthio) phenyl obtained in Synthesis Example 20 Dissolve 2.0 g of -4'-methylthiophenyl-dimethoxymethane in 8.0 g of DMF, add 0.61 g of chloromethyl methyl ether and 1.1 g of potassium carbonate, and stir at 70 ° C. for 12 hours. After stirring, 16 g of pure water and 32 g of methylene chloride are added to recover the organic layer, which is further washed twice with pure water. Thereafter, the organic solvent was distilled off and purified by column chromatography (ethyl acetate / hexane = 1/2 (volume ratio)) to give 4- [4- (methoxymethoxy) phenylthio] phenyl-4′-methylthiophenyl- 1.2 g of dimethoxymethane are obtained. The sum total of Hammett substituent constants σ is 0.2 or less.

Synthesis Example 23 Synthesis of 4- [4- (t-butoxycarbonyloxy) phenylthio] phenyl-4′-methylthiophenyl-dimethoxymethane (precursor compound B12) 4- (4-hydroxyphenyl) obtained in Synthesis Example 20 Thio) phenyl-4'-methylthiophenyl-dimethoxymethane (2.0 g) is dissolved in 12.0 g of methylene chloride, and 1.6 g of di-tert-butyldicarbonate, 0.76 g of triethylamine, N, N-dimethyl-4 Add 92 mg of aminopyridine and stir at room temperature for 6 hours. After stirring, 12 g of pure water is added to recover the organic layer, which is further washed twice with pure water. Thereafter, the organic solvent was distilled off, and purification was performed by column chromatography (ethyl acetate / hexane = 1/3 (volume ratio)) to give 4- [4- (t-butoxycarbonyloxy) phenylthio] phenyl-4′- 1.3 g of methylthiophenyl-dimethoxymethane are obtained. The sum total of Hammett substituent constants σ is 0.2 or less.

(Synthesis Example 24) Synthesis of Copolymer A 8.0 g of polyhydroxystyrene (weight average molecular weight 8000) and 0.010 g of 35% hydrochloric acid aqueous solution are dissolved in 28 g of dehydrated dioxane. Thereto, 2.73 g of cyclohexyl vinyl ether is dissolved in 2.80 g of dehydrated dioxane and added dropwise to the polyhydroxystyrene solution over 30 minutes. After dropping, the mixture is stirred at 40 ° C. for 2 hours. After stirring and cooling, 0.014 g of dimethylaminopyridine is added. Thereafter, the solution is dropped into 260 g of pure water to precipitate the copolymer. The solid obtained by separating this by filtration under reduced pressure was washed twice with 300 g of pure water and then vacuum-dried to obtain 9.2 g of copolymer A shown below as a white solid. The monomer ratio of the copolymer unit in the present invention is not limited to the following.

Synthesis Example 25 Synthesis of Copolymer B 7.0 g acetoxystyrene, 3.4 g 2-methyladamantane-2-methacrylate, 0.022 g butyl mercaptan and 0.40 g dimethyl-2,2′-azobis (2-Methylpropionate) (AIBN) is dissolved in 35 g of tetrahydrofuran (THF) and deoxygenated. This is dripped over 4 hours in 20 g of THF which has been brought to a reflux temperature in advance by flowing nitrogen gas. After dropping, the mixture is stirred for 2 hours and then cooled to room temperature. This is dropped into a mixed solvent of 149 g of hexane and 12 g of THF to precipitate the copolymer. The solid obtained by separating this by vacuum filtration was washed with 52 g of hexane, and then vacuum-dried to obtain 10.3 g of a copolymer B represented by the following formula as a white solid. The weight average molecular weight determined by gel permeation chromatography using polystyrene conversion is 9,200. The monomer ratio of the copolymer unit in the present invention is not limited to the following.

(Synthesis Example 26) Synthesis of Copolymer C 6.0 g of copolymer B, 6.0 g of triethylamine, 6.0 g of methanol and 1.5 g of pure water were dissolved in 30 g of propylene glycol monomethyl ether and refluxed for 6 hours. Stir. Thereafter, the mixture is cooled to 25 ° C., and the obtained solution is dropped into a mixed solution of 30 g of acetone and 30 g of pure water to precipitate the copolymer. The solid obtained by separating this by vacuum filtration was washed twice with 30 g of pure water, and then vacuum-dried to obtain 4.3 g of copolymer C represented by the following formula as a white solid. The weight average molecular weight determined by polystyrene conversion using gel permeation chromatography is 9100. The monomer ratio of the copolymer unit in the present invention is not limited to the following.

(Synthesis Example 27) Synthesis of Copolymer D 5.0 g of α-methacryloyloxy-γ-butyrolactone, 6.0 g of 2-methyladamantane-2-methacrylate, 3.6 g of 2-hydroxynorbornene-1-methacrylate, V601.51 g is dissolved in 26 g of tetrahydrofuran and degassed under reduced pressure. This is dripped over 4 hours in the flask which refluxed THF4g. After dropping, the mixture is stirred for 2 hours and then cooled to 25 ° C. This solution is reprecipitated by dropping it into a mixed solvent consisting of 160 g of hexane and 18 g of tetrahydrofuran. This is filtered, dispersed and washed twice with 37 g of hexane, and vacuum dried after filtration to obtain 7.7 g of the desired copolymer D as a white powder. The weight average molecular weight calculated | required by polystyrene conversion using the gel permeation chromatography is 9700.

(Synthesis Example 28) Synthesis of Copolymer E 0.80 g of the precursor compound B8, 3.9 g of α-methacryloyloxy-γ-butyrolactone, 2.9 g of 2-methyladamantane-2-methacrylate, (4 -Hydroxy) phenyl methacrylate 2.3 g, butyl mercaptan 0.13 g, V601 0.58 g are dissolved in tetrahydrofuran 12.5 g and degassed under reduced pressure. After deaeration, the solution is added dropwise over 4 hours to a flask in which 4 g of THF is refluxed by turning into a nitrogen stream. After dropping, the mixture is stirred for 2 hours and then cooled to 25 ° C. After cooling, it is reprecipitated by dropping it into a mixed solvent consisting of 107 g of hexane and 11 g of tetrahydrofuran.
This is filtered, then dispersed and washed twice with 37 g of hexane, filtered and vacuum dried to obtain 6.2 g of the target copolymer E as a white powder. The weight average molecular weight calculated | required by polystyrene conversion using the gel permeation chromatography is 8600.

Synthesis Example 29 Synthesis of Copolymer F 0.80 g of the above precursor compound B8, 3.9 g of α-methacryloyloxy-γ-butyrolactone, 2.9 g of 2-methyladamantane-2-methacrylate, (4 -Hydroxy) phenyl methacrylate 2.3 g, 5-phenyldibenzothiophenium 1,1-difluoro-2- (2-methacryloyloxy) -ethanesulfonate 0.49 g, butyl mercaptan 0.13 g and (4-hydroxy) 2.9 g of phenyl methacrylate and 0.56 g of dimethyl-2,2′-azobis (2-methylpropionate) (product name V601, manufactured by Wako Pure Chemical Industries, Ltd. (hereinafter referred to as “V601”)) Each is weighed and dissolved in 12.2 g of tetrahydrofuran and degassed under reduced pressure. After deaeration, the solution is added dropwise over 4 hours to a flask in which 4 g of THF is refluxed by turning into a nitrogen stream. After dropping, the mixture is stirred for 2 hours and then cooled to 25 ° C. After cooling, it is reprecipitated by dropping it into a mixed solvent consisting of 107 g of hexane and 11 g of tetrahydrofuran. This is filtered, then dispersed and washed twice with 37 g of hexane, filtered and vacuum dried to obtain 6.6 g of the desired copolymer F as a white powder. The weight average molecular weight determined by polystyrene conversion using gel permeation chromatography is 9100.

Synthesis Example 30 Synthesis of Copolymer G α-Methacryloyloxy-γ-butyrolactone 5.0 g, 2-methyladamantane-2-methacrylate 6.0 g, V601 0.51 g, and tetrahydrofuran 26 g were dissolved. Perform vacuum degassing. This is dripped over 4 hours in the flask which refluxed THF4g. After dropping, the mixture is stirred for 2 hours and then cooled to 25 ° C. This solution is reprecipitated by dropping it into a mixed solvent consisting of 160 g of hexane and 18 g of tetrahydrofuran. This is filtered, dispersed and washed twice with 37 g of hexane, and vacuum dried after filtration to obtain 7.4 g of the desired copolymer G as a white powder.

Comparative Synthesis Example 1 Synthesis of Copolymer H 5.0 g of α-methacryloyloxy-γ-butyrolactone, 6.0 g of 2-methyladamantane-2-methacrylate, 4.0 g of adamantane-1-methacrylate, and V601 0.51 g is dissolved in 26 g of tetrahydrofuran and degassed under reduced pressure. This is dripped over 4 hours in the flask which refluxed THF4g. After dropping, the mixture is stirred for 2 hours and then cooled to 25 ° C. This solution is reprecipitated by dropping it into a mixed solvent consisting of 160 g of hexane and 18 g of tetrahydrofuran. This is filtered, dispersed and washed twice with 37 g of hexane, and vacuum dried after filtration to obtain 8.0 g of the desired copolymer H as a white powder. The weight average molecular weight calculated | required by polystyrene conversion using the gel permeation chromatography is 8800.

<Sample Preparation 1 for Sensitivity Evaluation ("Evaluation Sample")>
Evaluation samples 1 to 20 are prepared as follows. 7000 mg of cyclohexanone, 500 mg of copolymer A, C and G, 507 mg of copolymer E, 497 mg of copolymer F and 500 mg of copolymer H, and diphenyliodonium-nona as a photoacid generator (PAG) 0.043 mmol of fluorobutanesulfonate (DPI-Nf) or phenyldibenzothionium-nonafluorobutanesulfonate (PBpS-Nf), precursor compounds B1 to 3, B9 and B10 as photosensitizer precursors and 2 as comparative compounds , 2-diphenyl-1,3-dioxolane (compound C1) (the sum of Hammett substituent constants σ is 0, the molar extinction coefficient at 365 nm in chloroform solvent is 6.3 × 10 ⁴ cm ² / mol) Each with 0.043 mmol or no addition, A sample is prepared by adding 0.0043 mmol of trioctylamine as a carrier, 0.3 mg of Novac FC-4434 as a surfactant, and 0.0015 mmol of 2-hydroxy-3-naphthoic acid as a carboxylic acid compound. Details of the prepared samples are shown in Table 1.

<Sample evaluation 1>
Each of the evaluation samples 1 to 20 is applied onto a Si wafer that has been subjected to hexamethyldisilazane (HMDS) treatment in advance, spin-coated, and heated at 110 ° C. to obtain a resist film having a thickness of 100 nm.
Next, the evaluation sample resist film is exposed by changing the exposure amount so that a 1: 1 line and space pattern having a line width half pitch of 100 nm is formed by an EB drawing apparatus of 30 keV. Thereafter, the entire surface of the wafer is irradiated with ultraviolet rays using a UV light having an emission line of 365 nm. Subsequently, it heats at 110 degreeC on a hotplate for 1 minute. After heating, develop with a developer (product name: NMD-3, 2.38 mass% tetramethylammonium hydroxide, manufactured by Tokyo Ohka Kogyo Co., Ltd.) for 1 minute, and rinse with pure water. Get the pattern with. This is observed with a microscope, and the exposure amount at which the resist is completely peeled is defined as E size (minimum exposure amount). Table 2 shows the results of evaluating the minimum exposure amount as sensitivity.

As shown in Table 2, Examples 1 to 9 and 13 to 16 using the resist composition mixed with the photosensitizer precursor according to one embodiment of the present invention had a minimum EB by UV irradiation after EB irradiation. The exposure amount becomes small. As a result, in the resist compositions of Examples 1 to 9 and 13 to 16, the acid generation is improved by the photosensitization of the photosensitizer generated from the photosensitizer precursor, and the sensitivity is improved. I understand. Furthermore, from the comparison between Example 4 and Comparative Example 1 and Example 7 and Comparative Example 2, the acid generation efficiency by EB is improved by including a compound having a hydroxy group in the resist as compared with the resist having no hydroxy group. It can be seen that the sensitivity is increased.

From the comparison of Examples 1 to 4 and Comparative Example 1, even when the same precursor compound B1 was used as a photosensitizer precursor, copolymers A and C having a high proportion of hydroxy groups, particularly hydroxyaryl groups, in the composition. Has high photosensitizing efficiency. The reason for this is that, in addition to the fact that the hydroxyaryl group works as an excellent proton donor among the hydroxyl groups, the copolymer has many hydroxy groups, so the polarity of the resist is increased, and it is generated from the photosensitizer precursor. It is considered that the stabilization of the obtained photosensitizer increases the wavelength of absorption and increases the molar absorption coefficient at 365 nm. Furthermore, the effect of UV irradiation is greater than the comparison between Examples 4 and 5 in that the molar extinction coefficient of the photosensitizer produced from the photosensitizer precursor is large if the sum of the Hammett substituent constants σ is 0.2 or less. There is a tendency toward higher sensitivity.

Also, as shown in Examples 10 and 11, when the precursor compound B8 is bonded in the polymer, the efficiency of acid generation by UV irradiation is higher than in Examples 1-9. This is because the photosensitizer generated is uniformly dispersed in the resist, and therefore the reaction probability between the photosensitizer and the photoacid generator is higher than when the photosensitizer precursor is mixed in the resist. It is thought that. When precursor compound B8 and PAG are combined in the polymer as shown in Example 12, the efficiency of acid generation by UV irradiation is higher than in Examples 10 and 11.

When Examples 5, 13 and 14 are compared, when the precursor compound B9 or B10 is mixed in the resist, the sensitivity is higher than when the precursor compound B2 is mixed in the resist. This is because, like sensitizer compounds A7 and A8 produced from precursor compounds B9 and B10, an increase in the molar extinction coefficient of 365 nm by introducing a 4-hydroxyphenylthio group, and an electron donating property due to the phenolic hydroxyl group. This is thought to be due to the improvement. Furthermore, it is considered that the acid generation efficiency of the photosensitization occurring between the photosensitizer and the acid generator is improved by the phenolic hydroxyl group of the photosensitizer becoming a proton source.

The compound C1 added in Comparative Examples 3 and 4 has a sum of Hammett substituent constants σ of 0 or more and a molar extinction coefficient at 365 nm of 6.3 × 10 ⁴ cm ² / mol, which is very low, so the sensitization efficiency in UV However, UV irradiation at 200 mJ / cm ² did not improve the amount of acid generated and did not increase the sensitivity.
From the above, it is considered that a highly sensitive photosensitizer precursor can be obtained by adding an electron-donating group to the compound to increase the molar absorption coefficient at 365 nm.

<Preparation of sample 2 for sensitivity evaluation ("evaluation sample")>
Evaluation samples 16 to 25 are prepared as follows. To 7000 mg of cyclohexanone, 500 mg of the copolymer A or H, and diphenyliodonium-nonafluorobutanesulfonate (DPI-Nf), phenyldibenzothionium-nonafluorobutanesulfonate (PBpS-Nf) or (PAG) as a photoacid generator (PAG) 0.043 mmol of 4-phenylthio) phenyldiphenylsulfonium-nonafluorobutanesulfonate (PSDPS-Nf) and 0.043 mmol of any of sensitizer compounds A1, A2, A7 and A8 as photosensitizers, respectively, or A sample is prepared by adding no trioctylamine as a quencher at a ratio of 0.0043 mmol. Details of the prepared samples are shown in Table 3.

<Sample evaluation 2>
Hexamethyldisilazane (each evaluation sample 21 to 32 is applied onto a Si wafer that has been subjected to HMDS treatment, spin-coated, and heated at 110 ° C. to obtain a resist film having a thickness of 500 nm.
Next, the evaluation sample resist film is exposed by changing the exposure amount with a UV exposure apparatus having a bright line of 365 nm through a 1: 1 line having a line width half pitch of 2 μm and a space pattern mask. Subsequently, it heats at 110 degreeC on a hotplate for 1 minute.
After heating, develop with a developer (product name: NMD-3, 2.38 mass% tetramethylammonium hydroxide, manufactured by Tokyo Ohka Kogyo Co., Ltd.) for 1 minute, and rinse with pure water. Get the pattern with. This is observed with a microscope, and the exposure amount at which the resist is completely peeled is defined as E size (minimum exposure amount). Table 4 shows the results of evaluating the minimum exposure amount as sensitivity.

As shown in Comparative Example 5, PBpS-Nf does not generate acid because there is no UV absorption at 365 nm, but Examples 17, 18, and 21 using resist compositions mixed with photosensitizers in one embodiment of the present invention. , 24, and 25 can generate an acid when the added photosensitizer absorbs light during UV irradiation and sensitizes the acid generator. Further, it can be seen that each example has higher sensitivity than Comparative Examples 6 and 7 in which an acid generator having UV absorption at 365 nm is mixed. Thus, in the resist compositions of Examples 17 to 25, the acid generation was improved and the sensitivity was improved. From the results of Example 20 and Comparative Example 6 and Example 23 and Comparative Example 7, the irradiation wavelength was improved. It can be seen that even an acid generator that absorbs UV has higher sensitivity due to the effect of the photosensitizer.

Comparison of Examples 17, 18, 24 and 25 shows that the greater the molar extinction coefficient of the added sensitizer compound, the higher the sensitivity. In addition, Examples 24 and 25 are considered to be more sensitive because electron donating property is improved by introducing a hydroxy group into the thioaryl structure as in sensitizer compounds A7 and A8. Furthermore, it is considered that the effect of improving the acid generation efficiency in the sensitization reaction that occurs between the photosensitizer and the acid generator is also observed by using the phenolic hydroxyl group of the sensitizer compound as a proton source.

According to some aspects of the present invention, a resist composition including a photosensitizer precursor for improving acid generation efficiency and forming a photoresist having high sensitivity, high resolution, and high LWR characteristics can be provided. .

Claims

A photosensitizer precursor represented by the following general formula (1);
A photoacid generator;
A hydroxy group-containing compound;
A resist composition comprising an acid-reactive compound.

(1)
(In the formula (1), Ar 1 and Ar 2 are each independently a phenylene group which may have a substituent,
R 1 is any one selected from the group consisting of an optionally substituted thioalkoxy group, arylthio group, and thioalkoxyphenyl group;
X is any selected from the group consisting of a sulfur atom, an oxygen atom and a direct bond;
R 2 is either an alkyl group which may have a substituent or a phenyl group,
Y is each independently one of an oxygen atom and a sulfur atom,
R 3 and R 4 are each independently a linear, branched or cyclic alkyl group that may have a substituent,
R 3 and R 4 may be bonded to each other to form a ring structure with two Ys in the formula,
At least one of the carbon-carbon single bonds in the alkyl group of R 1 , R 2 , R 3 and R 4 may be replaced with a carbon-carbon double bond or a carbon-carbon triple bond;
At least one of the methylene groups in the alkyl group of R 1 , R 2 , R 3 and R 4 may be replaced with a divalent heteroatom-containing group. )
The resist composition according to claim 1, wherein the hydroxy group-containing compound is a hydroxyaryl group-containing compound.
3. The resist composition according to claim 1, wherein a molar extinction coefficient at 365 nm after the photosensitizer precursor is treated with an acid is 1.0 × 10 5 cm 2 / mol or more.
4. The resist composition according to claim 1, wherein Ar 1 and / or Ar 2 has an electron donating group as a substituent.
The resist composition according to claim 4, wherein the electron donating group is selected from the group consisting of an alkyl group, an alkenyl group, an alkoxy group, and a thioalkoxy group.
The Ar 1 and / or Ar 2 further has at least one selected from the group consisting of an alkoxy group, a thioalkoxy group, an arylthio group, and a thioalkoxyphenyl group as a substituent, and the substituent is the Ar 1 The resist composition according to any one of claims 1 to 5, which is bonded to the ortho position and / or the para position of Ar 2 .
The resist composition according to any one of claims 1 to 6, wherein R 1 is bonded to the ortho or para position of Ar 1 .
The resist composition according to any one of claims 1 to 7, wherein when X is a sulfur atom or an oxygen atom, X is bonded to the ortho or para position of Ar 2 .
The at least two selected from the group consisting of the photosensitizer precursor, the photoacid generator, the hydroxy group-containing compound, and the acid-reactive compound are included as units bonded to the same polymer. The resist composition as described in any one of these.
The resist composition according to any one of claims 1 to 9, further comprising at least one selected from the group consisting of an acid diffusion controller, a surfactant, a dissolution inhibitor, and a solvent.
Applying the resist composition according to any one of claims 1 to 10 on a substrate to form a resist film;
Irradiating the resist film with a first active energy ray;
Irradiating the resist film after the first active energy ray irradiation with a second active energy ray;
And developing a resist film after the second active energy ray irradiation to obtain a pattern.
The first active energy ray is a particle beam or an electromagnetic wave;
When the first active energy ray is a particle beam, the second active energy ray is an electromagnetic wave, and when the first active energy ray is an electromagnetic wave, the second active energy ray is the electromagnetic wave of the first active energy ray. The device manufacturing method according to claim 11, wherein the electromagnetic wave is longer than the wavelength of the device.
The device manufacturing method according to claim 11 or 12, wherein the first active energy ray is an electron beam or extreme ultraviolet rays.