JPWO2017188297A1 - Resist composition and method of manufacturing device using the same - Google Patents

Abstract

Disclosed is a resist composition for improving acid generation efficiency and providing a photoresist having high sensitivity, high resolution and high LWR characteristics.
The compound represented by following General formula (1).
[Chemical formula 1]

(1)
(In the above 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, an arylthio group and a thioalkoxyphenyl group,
X is any one selected from the group consisting of a sulfur atom, an oxygen atom and a direct bond,
R ² is any of an alkyl group and an aryl group which may have a substituent,
Y is 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, and said R ³ and R ⁴ are bonded to each other to form And may form a ring structure with two Y,
At least one carbon-carbon single bond in the alkyl group possessed by R ¹ , R ² , R ³ and R ⁴ may be replaced by a carbon-carbon double bond or a carbon-carbon triple bond,
At least one of the methylene groups in the alkyl group possessed by R ¹ , R ² , R ³ and R ⁴ may be replaced by a divalent hetero atom-containing group. )

Description

  Some aspects of the present invention relate to a composition that can be used for resist patterning and a method of manufacturing a device using the same.

  In semiconductor devices, for example, highly integrated circuit elements represented by DRAM and the like, demands for higher density, higher integration, and higher speed are high. Accordingly, in various electronic device manufacturing fields, a demand for establishment of a half-micron-order microfabrication technology, for example, development of a photolithography technology for micropattern formation, is becoming increasingly severe. In order to form a fine pattern in the photolithographic 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 the 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). The characteristic of the chemical amplification type photoresist is that an acid is generated from the photoacid generator which is a component by irradiation of exposure light, and this acid causes an acid catalyzed reaction with a resist compound etc. by heat treatment after exposure.
With the miniaturization of semiconductor devices, the demand for EUV lithography technology using EUV (Extreme Ultra Violet) light having a wavelength of 13.5 nm as exposure light is increasing. However, the biggest drawback of EUV lithography is the lack of power of the EUV light source. Therefore, although a highly sensitive photoresist is required, there is a trade-off relationship between sensitivity, resolution and LWR (Line Width Roughness), and there is a problem that the resolution decreases and the roughness increases when the sensitivity is increased.

JP 10-7650 A Unexamined-Japanese-Patent No. 2003-327572 JP, 2008-7410, A

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

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

As a result of intensive studies to solve the above problems, the inventors of the present invention have found that a photosensitizer precursor that can be dissociated by an acid to become a photosensitizer, a photoacid generator, and 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 composition containing a photosensitizer precursor, a photoacid generator, a hydroxy group-containing compound and an acid reactive compound is chemically modified. The photosensitizer is used as an amplification type photoresist composition, and the photosensitizer precursor is acid-dissociated by an acid generated from a photoacid generator by irradiation with a first active energy ray such as EUV light or electron beam (EB), for example, for photosensitization It was found that when the second photoirradiant is further irradiated with UV light or the like as an agent, electron transfer to the photoacid generator occurs to improve the acid generation efficiency.

  One embodiment 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 each independently represent a phenylene group which may have a substituent,
R ¹ is any one selected from the group consisting of an optionally substituted thioalkoxy group, an arylthio group and a thioalkoxyphenyl group,
X is any one selected from the group consisting of a sulfur atom, an oxygen atom and a direct bond,
R ² is any of an alkyl group and an aryl group which may have a substituent,
Y is 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, and the above R ³ and R ⁴ are bonded to each other to form a formula May form a ring structure with the two Y in the
At least one carbon-carbon single bond in the alkyl group possessed by R ¹ , R ² , R ³ and R ⁴ may be replaced by a carbon-carbon double bond or a carbon-carbon triple bond,
At least one of the methylene groups in the alkyl group possessed by R ¹ , R ² , R ³ and R ⁴ may be replaced by a divalent hetero atom-containing group. )

  The resist composition which is one aspect 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 aspect of the present invention is characterized by being represented by the following general formula (1).

In the above 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, an arylthio group and a thioalkoxyphenyl group,
X is any one selected from the group consisting of a sulfur atom, an oxygen atom and a direct bond,
R ² is any of an alkyl group and an aryl group which may have a substituent,
Y is 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,
R ³ and R ⁴ may be bonded to each other to form a ring structure with two Y in the formula,
At least one carbon-carbon single bond in the alkyl group possessed by R ¹ , R ² , R ³ and R ⁴ may be replaced by a carbon-carbon double bond or a carbon-carbon triple bond,
At least one of the methylene groups in the alkyl group possessed by R ¹ , R ² , R ³ and R ⁴ may be replaced by a divalent hetero atom-containing group.

The photosensitizer precursor in one aspect of the present invention preferably has a sum of Hammett substituent constants σ of 0.2 or less.
In the present invention, the total of the Hammett substituent constant σ is each Ar ¹ and each Ar ¹ and Ar 4 and Ar ^{2 in} the above general formula (1) based on the group to which the quaternary carbon bonded to Ar ¹ and Ar ² is bonded. The sum of the Hammett substituent constant σ of each substituent bonded to Ar ² is referred to.
The Hammett substituent constant σ is the value of 1935 in order to quantitatively discuss the influence of substituents on the reaction or equilibrium of benzene derivatives. P. It is a value (sum of σp value, σm value, and σo value) obtained by an empirical rule proposed by Hammett.
Among the substituent constants determined by the Hammett rule, the values of the σp value and the σm value are, for example, those described in J. A. Dean, ed., "Lange's Handbook of Chemistry", 12th Edition, 1979 (McGraw-Hill) and "Area of Chemistry", Supplement, No. 122, pp. 96-103, 1979 (Nanko-do).
Further, the σo values discussed with respect to the effects of steric hindrance are, for example, Nuclear magnetic resonance studies of ortho-substituted phenols in dimethyl sulfoxide solutions. Electronic effects of ortho substituents J. Am. Chem. Soc. , 1969, 91 (2), pp 379-388, M., et al. Thomas and James G. It is disclosed in detail in Traynham.

The sum of the Hammett substituent constant σ of the photosensitizer precursor is preferably 0.2 or less, more preferably -0.01 or less. Moreover, it is preferable that it is -3.00 or more. The Hammett substituent constant σ of the substituent that Ar ¹ in the general formula (1) has is preferably 1 or less. It is preferable that the Hammett substituent constant (sigma) of the substituent which Ar < ² > in the said General formula (1) has is 1 or less. The Hammett substituent constant σ of the photosensitizer precursor is set by setting the sum of the Hammett substituent constant σ of the substituent that Ar ¹ has and the Hammett substituent constant σ of the substituent that Ar ² has to 0.2 or less. Is less than 0.2.
When the sum total of the Hammett substituent constant σ of the photosensitizer precursor is within the above range, it becomes an electron donating property, and when the photosensitizer precursor is acid-dissociated to become a photosensitizer, the photoacid The acid generation efficiency of the generator can be improved. In order to make the sum total of Hammett substituent constant σ 0.2 or less, according to Hammett substituent constant σ disclosed above, an electron donating group or an electron withdrawing substituent is appropriately selected for Ar ¹ and Ar ² above. The Hammett substituent constant σ may be adjusted by introducing it and 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 the substituents other than R ¹ or other than —X—R ² (hereinafter referred to as “substituents for Ar ¹ and Ar ² It may have a substituent "). Ar ¹ and Ar ² are preferably not directly or indirectly bonded to form a ring from the viewpoint of synthesis.
Examples of the first substituent include an electron donating group, and 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. It can be mentioned. A long chain alkoxy group having a polyethylene glycol chain (— (CH ₂ CH ₂ O) _n —) may also be mentioned as the first substituent. 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 of such "para" of Ar ¹ or Ar ² is located relative to the two Y and Ar ¹ and Ar ² 4 tertiary group in which the carbon is bonded to bind to the above formula (1) Say Not only for the first substituent but also for other groups, the reference of the substitution position such as “para-position” is the position relative to the group to be bonded to the quaternary carbon.
The alkyl group as the first substituent is not particularly limited, and examples thereof include 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, a cyclohexyl group and an adamantyl group. A C1-C20 linear, branched, and cyclic alkyl group is mentioned. 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, the arylthio group and the thioalkoxyphenyl group as the first substituent include the same as the thioalkoxy group, the arylthio group and the thioalkoxyphenyl group 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, it is bound to the ortho position and / or the para position of a phenylene group which is Ar ¹ and Ar ² Is preferred. 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 one selected from the group consisting of a thioalkoxy group which may have a substituent, an arylthio group and a thioalkoxyphenyl group.
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, a thio n-butoxy group, etc. An alkoxy group is more preferred.
Specific examples of the arylthio group for R ¹ include a phenylthio group and a naphthylthio group.

Specifically, preferred examples of the thioalkoxyphenyl group as R ¹ include a phenyl group having a C ¹ -C 20 thioalkoxy group such as a thiomethoxyphenyl group, a thioethoxyphenyl group, a thiopropoxyphenyl group, and a thiobutoxyphenyl group bonded. And more preferably a phenyl group having a C 1-12 thioalkoxy group bonded thereto. The substitution position of the thioalkoxy group bonded to the phenylene group in R ¹ is not particularly limited, but is preferably in the para position from the viewpoint of enhancing the electron donating property and the molar absorption coefficient at 365 nm.
The R ¹ is preferably bonded to the ortho or para position of the phenylene group which is Ar ¹ .

R ² in the above formula (1) is either an alkyl group which may have a substituent or an aryl group.
The alkyl group for R ² is linear or branched 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 and cyclohexyl group And cyclic alkyl groups.
Examples of the aryl group of 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 substituent of R ¹ and R ² is referred to as “second substituent”), Although not particularly limited, in addition to the above-mentioned first substituent, nitro group, sulfonyl group, carbonyl group, hydroxy group and the like can be 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, etc. This is preferable because the molar absorption coefficient at 365 nm is increased.
Although mentioned later, you may introduce | transduce a polymeric group into said R < ¹ > or R < ² >, and you may use what polymerized this as a polymer which provided the sensitizing effect. That is, a polymer containing, as a unit, a moiety having the action of a photosensitizer precursor as a unit is also a photosensitizer precursor in one aspect of the present invention, and the second substituent comprises a polymer main chain, It is also good. Examples of the polymerizable group include (meth) acryloyloxy group, epoxy group, vinyl group and the like.
In addition, "(meth) acryloyl" represents acryloyl and methacryloyl.

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

At least one of carbon-carbon single bond in the alkyl group which R ¹ , R ² , the first substituent and the second substituent have is replaced by 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 by a divalent hetero atom-containing group.
Examples of the divalent hetero atom-containing group include —O—, —CO—, —COO—, —OCO—, —O—CO—O—, —NHCO—, —CONH—, and —NH—CO—O—. And at least one member selected from the group consisting of -O-CO-NH-, -NH-, -N (R)-, -N (Ar)-, -S-, -SO- and -SO _2- It is a divalent organic group. Moreover, it is preferable that R < ¹ >, R < ² >, the said 1st substituent, and a 2nd substituent do not have a continuous connection of hetero atoms, such as -OO- and -SS-.
R is the same as the alkyl group exemplified as the first substituent.
Ar is the same as the aryl group of R ² .
The total number of carbon atoms of R ¹ in the formula (1) is not particularly limited, it is preferable that the total carbon number of 1 to 20 with or without substituents R ^1. The total number of carbon atoms of R ² in the formula (1) is not particularly limited, it is preferable that the total carbon number of 1 to 20 with or without substituents R ^2.
When the photosensitizer precursor is a polymer, it is preferable that the total carbon number of R ¹ and R ² is 1 to 20 excluding the portion including the polymer main chain to be the second substituent.
R ¹ , R ² , the first substituent and the second substituent may have an acid dissociable group. The acid dissociable group may be a protective group which is deprotected by the action of an acid, and examples thereof include t-butoxycarbonyloxy group, methoxymethoxy group, ethoxymethoxy group, trimethylsilyloxy group, tetrahydropyranyloxy group and 1- An ethoxy ethoxy group etc. are mentioned. In the resist composition according to one aspect 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 the solubility contrast in the exposed area and the unexposed area is obtained. It is preferable because it becomes easy to be removed.

Y is 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 for R ³ and R ^4, a linear group 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. It includes branched and cyclic alkyl groups.
From the point of synthesis, it is preferred that the above R ³ and R ⁴ are the same.
In the present invention, by using R ³ and R ⁴ as the groups shown above, the photosensitizer precursor may be deprotected by an acid to have a carbonyl group.

The R ³ and R ⁴ may be bonded to each other to form a ring structure with two Y in the formula.
That is, the photosensitizer precursor in one aspect 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. n is not particularly limited as long as it is 2 or more, but is preferably 8 or less from the viewpoint of ease of synthesis. In addition, n is preferably 3 or more from the viewpoint of activation energy of a cyclic acetal protecting group described 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, non-cyclic acetals are known to have low activation energy as compared to cyclic acetals, and cyclic acetal compounds have high hydrolysis rates. Among cyclic acetal compounds, a 5-membered ring structure such as 1,3-dioxolane has high activation energy and stability, while a 6-membered ring such as a 1,3-dioxane structure or a 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, for example, in the 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 aspect of the present invention preferably has low activation energy of the acetal protecting group. This is because the photosensitizer precursor is easily converted to a photosensitizer by the acetal deprotection reaction. 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. Further, in the above formula (2), which is a case where R ³ and R ⁴ are mutually bonded to form a ring structure with two Y in the formula, -R ⁵ -R ⁶ -is a group wherein 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 substituent of R ³ and R ⁴ is referred to as “third substituent”) Although it does not restrict | limit, In addition to said 2nd substituent, aryl groups, such as a phenyl group and a naphthyl group, etc. are mentioned.

At least one carbon-carbon single bond in the alkyl group that R ³ , R ⁴ and the third substituent have may be replaced by a carbon-carbon double bond or a carbon-carbon triple bond. In addition, at least one of the methylene groups in the alkyl group of R ³ , R ⁴ and the third substituent may be replaced by the 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 component of a polymer. Each of R ^{3 and} R ⁴ preferably has 1 to 20 carbon atoms in total regardless of the presence or absence of a substituent. In Formula (2) above, R ⁵ and R ⁶ may have the same third substituent as R ³ and R ⁴ above. A polymerizable group may be introduced into the above R ³ or R ^4, and a polymer obtained by polymerizing this may be used as a polymer to which a sensitizing function is imparted. That is, in the case where the photosensitizer precursor in one aspect of the present invention is a polymer containing a unit having the function of the photosensitizer precursor as a unit, a third substituent is substituted for the above-mentioned second substituent. The substituent may be configured to include a polymer main chain.
The total carbon number of R ³ and R ⁴ is preferably 1 to 20. When the photosensitizer precursor is a polymer, it is preferable that the total carbon number of R ³ and R ⁴ excluding the portion including the polymer main chain which is to be the third substituent is 1 to 20.

The photosensitizer precursor after acid treatment, that is, the photosensitizer having a carbonyl group formed when the photosensitizer precursor is deprotected by an acid, has a molar absorption coefficient at 365 nm of 1 It is preferable that it is more than 0. 10 ⁵ cm ² / mol. The molar absorption coefficient at 365 nm is preferably high, but a practical value is 1.0 × 10 ¹⁰ cm ² / mol or less. In order to make the molar absorption coefficient be in the above range, for example, the photosensitizer precursor has at least one selected from the group consisting of a thioalkoxy group, an arylthio group and a thioalkoxyphenyl group, or an alkoxy group and The constitution having two or more of any of aryloxy groups can be mentioned.
In the present invention, the molar absorption coefficient is at 365 nm in chloroform solvent or acetonitrile solvent measured by UV-VIS spectrophotometer using chloroform or acetonitrile as a solvent. The molar absorptivity of the photosensitizer having a carbonyl group in some embodiments of the present invention can be within the above range in either chloroform solvent or acetonitrile solvent.
In addition, the photosensitizer precursor in one aspect of the present invention is -Y-R ³ and -Y-R ⁴ in the entire photosensitizer precursor in terms of easiness of synthesis and light absorption characteristics. Or four or less 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 Is preferred.

  As a preferable example as a photosensitizer precursor represented by said Formula (1), the following photosensitizer precursor can be illustrated, for example. In the following examples, those shown in parentheses represent units of a polymer. The photosensitizer precursor in some aspects of the present invention is not limited thereto.

<2> Method of Synthesizing Photosensitizer Precursor The method of synthesizing a photosensitizer precursor according to one aspect of the present invention will be described. The present invention is not limited to this.
When the photosensitizer precursor in one aspect 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 alkoxybenzoyl chlorides having an —X—R ² group, alkyl benzoyl chlorides, thioalkoxy benzoyl chlorides and thioalkyl benzoyl chlorides, and those in which these alkyl groups are aryl groups The compound is reacted with a Grignard reaction using a halogenated benzene having an R ¹ group to obtain a benzophenone derivative. Then, the benzophenone derivative is reacted with an alcohol and an ortho ester such as trialkyl orthoformate (R ³ , R ⁴ = alkyl group) as a dehydrating agent as needed at 0 ° C. to reflux temperature for 1 to 120 hours. Thus, the derivative represented by the following formula (3) can be obtained.

  When the photosensitizer precursor in one aspect of the present invention has a structure represented by the following formula (4), the derivative represented by the above formula (3) obtained above and 1,3-propanediol 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 camphor sulfonic acid.

  When 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, such as boron trichloride It can be obtained by reacting in the presence of a Lewis acid at -78 ° C to 0 ° C for 1 to 120 hours.

  When the photosensitizer precursor in one aspect 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 (IV) chloride.

  When the photosensitizer precursor in one aspect 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, boron trichloride and the like The reaction can be obtained by reacting at 0 to 100 ° C. for 1 to 120 hours in the presence of a Lewis acid of

  When the photosensitizer precursor in one aspect 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 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.

The photosensitizer precursor in one aspect of the present invention can efficiently proceed with the acetalization reaction by having a specific structure. It is preferable that Ar ¹ and Ar ² do not have a ring structure via a divalent group and the above quaternary carbon. The reason is that when Ar ¹ and Ar ² have a ring structure via a divalent group and the above 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 synthesis that Ar ¹ and Ar ² do not have a ring structure directly or via a divalent group and the above quaternary carbon.

<3> Photoacid Generator The acid generator in one embodiment of the present invention is not particularly limited as long as it is generally used in a chemically amplified resist composition, and, for example, an onium salt compound, N-sulfonyloxyimide A compound, a halogen containing compound, a diazo ketone compound etc. are mentioned. The photoacid generators can be used alone or in combination of two or more. It is preferable that the electron acceptability is high in consideration of the sensitivity of EUV and EB, and further, it is preferable that the molar absorption coefficient at 365 nm is 1.0 × 10 ⁴ cm ² / mol or less.
As onium salt compounds, sulfonium salts, iodonium salts, phosphonium salts, diazonium salts, pyridinium salts and the like can be mentioned. Examples of sulfonium salts and iodonium salts include those described in WO 2011/093139. Although the photo-acid generator represented by following formula (9) or (10) is mentioned specifically, It is not limited to this.

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 has a part of hydrogen atoms substituted with a fluorine atom It also shows good hydrocarbon groups. M ⁺ represents a counter cation.

R ^a COOCH ₂ CH ₂ CFHCF ₂ SO ₃ ^- M ⁺ (10)
In said Formula (10), ^Ra shows the C1-C200 monovalent organic group which may have a substituent. M ⁺ represents a counter cation.

  The photoacid generator may be added to the resist composition as a low molecular weight component, but may be contained as a polymer unit. That is, the embodiment may be included in the polymer as a unit so as to be bonded to the polymer main chain at any position of the photoacid generator. For example, when the photoacid generator is a sulfonium salt, it is preferable to have a bond which is bonded to the polymer main chain directly or via a linking group, instead of one H of the substituent in the sulfonium salt.

<4> Hydroxy Group-Containing Compound The hydroxy group-containing compound in one aspect of the present invention is not particularly limited as long as hydrogen of a hydroxy group can be a hydrogen source when the photoacid generator is decomposed. By containing the above-mentioned hydroxy group-containing compound in the resist composition, the acid generation efficiency from the above photo acid generator is improved, and the addition of a hydroxy group further increases the ionization potential compared to the case where it has no hydroxy group. It can be lowered.
As a hydroxy group-containing compound, for example, a unit derived from hydroxystyrene, hydroxyvinylnaphthalene, hydroxyphenyl acrylate, hydroxyphenyl methacrylate, hydroxynaphthyl acrylate, hydroxy norbornene acrylate, hydroxy norbornene methacrylate, hydroxy naphthyl methacrylate, hydroxy adamantane acrylate, hydroxy adamantane methacrylate, etc. Polymers that contain: bisphenol, polyphenol compounds such as TrisP-PA (made by Honshu Chemical Industry Co., Ltd.) calixarene, etc .; Among them, polymers containing units derived from hydroxystyrene, hydroxyvinyl naphthalene, hydroxyphenyl acrylate, hydroxyphenyl methacrylate, hydroxynaphthyl acrylate, hydroxynaphthyl methacrylate and the like are preferable. As a hydroxyaryl group containing compound, the polymer which has a unit shown by following formula (11) is mentioned.

In the formula (11), Ar ³ is an arylene group, R ⁷ is a hydrogen atom or a hydrocarbon group L is a carbonyl group or a direct bond.
The arylene group of Ar ³ may further have a hydroxy group in addition to the hydroxy group disclosed in Formula (11). The arylene group for Ar ³ 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, Further preferred is a phenylene group which may have a group.
The hydrocarbon group of R ⁷ is preferably an alkyl group having 1 to 12 carbon atoms. As R ⁷ , a hydrogen atom or a methyl group is more preferable.

  As the above-mentioned hydroxyaryl group containing compound, although a polymer which has a unit shown by a following formula is mentioned preferably, it is not limited to this.

<5> Acid Reactive Compound

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

  When the composition is used as a resist composition, for example, a compound having a protective group which is deprotected by an acid is a compound whose solubility in a developer changes by deprotecting the protective group with an acid to form a polar group. It is. For example, in the case of aqueous development using an alkaline developer, etc., the alkaline developer is insoluble in the alkaline developer, but the protective group is deprotected in the exposed area by the acid generated from the photoacid generator upon exposure. Is a compound that becomes soluble in

  In the present invention, the developing solution is not limited to the alkaline developing solution, and may be neutral developing solution or organic solvent development. Therefore, when an organic solvent developer is used, the compound having a protective group which is deprotected with 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 and 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 protective group, a compound having a styrene skeleton, a methacrylate or an acrylate skeleton in which the protective groups are pendant, and the like are suitably used.
The compound having a protecting group which is deprotected by 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 is one having a weight average molecular weight of less than 1000, and the polymer is one having a weight average molecular weight of 1,000 or more.

  The compound having a polymerizable group that is polymerized by an acid is, for example, a compound whose solubility in a developer changes when the composition is used as a resist composition and the polymerizable group is polymerized by 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 the solubility in the aqueous developer is It is a compound that decreases. Also in this case, an organic solvent developer may be used instead of the aqueous developer.

An epoxy group, a vinyloxy group, oxetanyl group etc. are mentioned as a polymeric group which superposes | polymerizes with an acid. As the compound having a polymerizable group, a compound having a styrene skeleton, a methacrylate or an acrylate skeleton, or the like having such a polymerizable group is suitably used.
The compound having a polymerizable group which is polymerized by an acid may be a polymerizable low molecular weight compound or a polymer.

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

<6> Composition Containing Photosensitizer Precursor According to one aspect of the present invention, the photosensitizer precursor, the photoacid generator, the hydroxy group-containing compound, and the acid reactive compound And a resist composition containing
The photosensitizer precursor according to some aspects of the present invention is a composition in which the photoacid generator generates an acid upon irradiation with an active energy ray or the like in the above composition, and the acid is deprotected by the acid to become a photosensitizer. obtain.
In the present invention, the photoacid generator generates an acid by the first irradiation using the first active energy ray, and the photosensitizer precursor is deprotected by the acid to become a photosensitizer, and By performing the second irradiation using the second actinic energy having a wavelength at which the photosensitizer absorbs light, the photoacid generator is regenerated again only in the portion where the first irradiation has been performed by the action of the photosensitizer. It is preferred to be able to generate an acid. As a result, the acid may generate a photosensitizer, and may react with an acid-reactive compound that reacts with the acid.

More specifically, the following can be illustrated as a resist composition which is one aspect of this invention.
A resist composition comprising the photosensitizer precursor, a compound having a protective group which is deprotected by the acid, and a photoacid generator; a compound having a polymerizable group which is polymerized by the photosensitizer precursor and the acid A resist composition containing the photoacid generator and the photoacid generator; a photosensitizer precursor, a crosslinker having a crosslinking action with an acid, and a compound that changes the solubility in a developer by reacting with the crosslinker. A resist composition containing a photoacid generator; and the like.
The photosensitizer precursor in one aspect 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 according to one aspect of the present invention is preferably 0.1 to 5 molar equivalents, and 0.5 to 2.0 molar equivalents with respect to the photo acid generator. Is more preferred. When at least one of the photosensitizer precursor and the photoacid generator is a polymer, it is based on mass excluding 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, further preferably 1 to 15 parts by mass. By incorporating 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, 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 above photosensitizer precursor, the above photoacid generator, the above hydroxy group-containing compound and the above acid reactive compound are contained as units bound to the same polymer. Is also preferred. This makes it possible to make the distribution in the resist composition uniform.
When the photosensitizer precursor is contained 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 photosensitization 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 all units of the polymer.

When the photoacid generator is contained 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 generation The unit acting as an agent is preferably 1 to 40 mol%, more preferably 5 to 35 mol%, and still more preferably 5 to 30 mol% in 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 3 to 90% by mole, more preferably 5 to 80% by mole, and more preferably 7 to 70% by mole, in all the units of the polymer for positive resist compositions for aqueous development. It is further preferred that For a negative resist composition for water-based development, it is preferably 60 to 99 mol%, more preferably 70 to 98 mol%, and still more preferably 75 to 98 mol%, in all units of the polymer.
When the acid-reactive 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 hydroxy group-containing compound, the photosensitization The unit acting as an agent precursor is preferably 3 to 40 mol%, more preferably 5 to 35 mol%, and still more preferably 7 to 30 mol% in all units of the polymer.

  The weight average molecular weight of the polymer in one aspect of the present invention is preferably 1000 to 200000, more preferably 2000 to 50000, and still more preferably 2000 to 15000. The preferred degree of dispersion (molecular weight distribution) (Mw / Mn) of the above polymer is 1.0 to 1.7, more preferably 1.0 to 1.2, from the viewpoint of sensitivity. The weight average molecular weight and the degree of dispersion of the above-mentioned polymer are defined as polystyrene conversion value by GPC measurement.

The composition according to one aspect of the present invention may further contain an acid diffusion control agent, a surfactant, an organic carboxylic acid, a solvent, a dissolution inhibitor, and the like, which are optionally used in the resist composition in addition to the above components. Stabilizers and dyes, and other sensitizers other than the photosensitizer precursor may be contained 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 area. Therefore, the storage stability of the obtained resist composition is improved, and the resolution as a resist is improved. At the same time, it is possible to suppress the line width change of the resist pattern due to the fluctuation of the placement time from exposure to development processing, and a resist composition excellent in process stability can be obtained.
Examples of the acid diffusion control agent include a compound having one, two or three nitrogen atoms in the same molecule, an amide group-containing compound, a urea compound, a nitrogen-containing heterocyclic compound and the like. Further, as an acid diffusion control agent, a photodisintegrable base which is sensitized by exposure to generate a weak acid can also be used. As the photodisintegrable base, for example, an onium salt compound, an iodonium salt compound, etc. which are decomposed by exposure to lose acid diffusion controllability can be mentioned.
Specifically, Japanese Patent No. 3577743, Japanese Patent Laid-Open No. 2001-215689, Japanese Patent Laid-Open No. 2001-166476, Japanese Patent Laid-Open No. 2008-102383, Japanese Patent Laid-Open No. 2010-23773, The compound as described in is mentioned.
The content of the acid diffusion control agent is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 5 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 to improve the coatability. Examples of surfactants include nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene polyoxypropylene block copolymers, sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters Agents, fluorosurfactants, organosiloxane polymers and the like.
The content of the surfactant is preferably 0.0001 to 2 parts by mass and more preferably 0.0005 to 1 parts by mass with respect to 100 parts by mass of the resist composition component.

Examples of the organic carboxylic acids include aliphatic carboxylic acids, alicyclic carboxylic acids, unsaturated aliphatic carboxylic acids, oxycarboxylic acids, alkoxycarboxylic acids, ketocarboxylic acids, benzoic acid derivatives, phthalic acid, terephthalic acid, isophthalic acid, 2 And-naphthoic acid, 1-hydroxy-2-naphthoic acid, 2-hydroxy-3-naphthoic acid and the like. An aromatic organic carboxylic acid, among them, for example, benzoic acid, 1-hydroxy-2-naphthoic acid, from the viewpoint of low risk of volatilizing from the resist film surface and contaminating the drawing chamber when performing electron beam exposure 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.

As the solvent, for example, 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-dimethylacetoamide , Propylene carbonate, ethylene carbonate, etc. are preferable. These solvents may be used alone or in combination.
The resist composition component is preferably dissolved in the above solvent so as to have a solid content concentration of 1 to 40% by mass. More preferably, it is 1-30 mass%, More preferably, it is 3-20 mass%. The above-mentioned film thickness can be achieved by setting it as the range of such solid content concentration.

The resist composition according to one aspect of the present invention may contain a fluorine-containing water-repellent polymer in addition to the above. The above-mentioned fluorine-containing water-repellent polymer is not particularly limited, and those generally used in an immersion exposure process may be mentioned, and it is preferable that the fluorine atom content is larger than that of the above-mentioned polymer. Thereby, when forming a resist film using a resist composition, the above-mentioned fluorine-containing water-repellent polymer can be localized on the resist film surface due to the water repellency 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) in place 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). Thus, it can be used as a photosensitizer having a large absorption of 1.0 × 10 ⁵ cm ² / mol or more at 365 nm, without the need for a deprotection reaction with an acid. Therefore, it can be suitably used as a chemically amplified resist composition for UV, and in particular, it can be suitably used for an optical device application requiring high visible light transmittance. In the case of a chemically amplified resist for UV, even if the resist composition does not contain a hydroxy group-containing compound, the acid generation efficiency can be improved by including the above-mentioned ketone derivative.

<7> Device Manufacturing Method One aspect of the present invention is a step of applying the above composition onto a substrate to form a resist film (hereinafter, also referred to as a “resist film forming step”); A step of irradiating an active energy ray (hereinafter also referred to as "first irradiating step") and a step of irradiating a second active energy ray to the resist film irradiated by the first active energy ray (hereinafter referred to as "second irradiation" And the step of obtaining the pattern by developing the resist film irradiated with the second active energy ray (hereinafter, also referred to as a “pattern forming step”).

As described above, in the present invention, the photoacid generator generates an acid by performing the first irradiation with the first active energy ray, and the photosensitizer precursor is deprotected by the acid to increase the photo It becomes 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 regenerated again only on the portion where the first irradiation is performed by the action of the photosensitizer. Preferably can generate an acid. As a result, the acid may generate a photosensitizer, and may react with an acid-reactive compound that reacts with the acid.
The first active energy ray used in the first irradiation may be any particle beam or electromagnetic wave capable of generating an acid by activating the photoacid generator contained in the composition, such as KrF excimer laser light or ArF excimer laser light, F ₂ excimer laser light, electron beam, UV, visible light, X-rays, ion beam, g-rays, h-line, i-line, and a EUV like. Among them, 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, and examples of the electromagnetic wave include KrF excimer laser light, ArF excimer laser light, F ₂ excimer laser light, UV, visible light, g-ray, h-ray, i-ray and the like. Can be 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 general device manufacturing method may be followed.

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

  In one aspect of the present invention, a film thickness of a resist film formed of the above-mentioned resist composition is preferably 10 to 200 nm. The above resist composition is coated on a substrate by a suitable coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, etc., and preferably at 60 to 150 ° C. for 1 to 20 minutes. Pre-bake at 120 ° C. for 1 to 10 minutes to form a thin film. The thickness of the coating film is 10 to 200 nm, preferably 20 to 150 nm.

  EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited in any way by these examples. In the following synthesis examples, the molar absorption coefficient of the compound after acid treatment, that is, the molar absorption coefficient at 365 nm of the benzophenone compound derivative obtained by deprotecting the compound is a UV-VIS absorptiometer (manufactured by Hitachi, Ltd.) It is determined by using a manufacturer U-3300) 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 is dissolved in 32 g of tetrahydrofuran, in which 1 mol / L methyl magnesium bromide is added. 39 ml of THF solution is added dropwise below 5 ° C. After the dropwise addition, the solution is stirred at 5 ° C. or less for 30 minutes to obtain a THF solution of 4-methylthiophenylmagnesium bromide. In a solution of 8.8 g of 2,4-dimethoxybenzoyl chloride in 15 g of THF, a THF solution of 4-methylthiophenylmagnesium bromide is added dropwise at 10 ° C. or less 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 less, 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 with 120 g of ethanol to give 7.6 g of 2,4-dimethoxy-4'-methylthiobenzophenone. The molar absorption 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 are dissolved in 12.5 g of methanol and this is stirred for 3 hours at reflux temperature. Thereafter, the reaction solution is cooled to room temperature, 50 g of a 5% by mass aqueous sodium hydrogen carbonate solution is added thereto, and the mixture is further stirred for 10 minutes, and the precipitated crystals are filtered. The crystals are recovered, redissolved in 50 g of ethyl acetate and 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 constant σ is −0.56.

Synthesis Example 3 Synthesis of 4-Fluoro-4′-Methylthiobenzophenone 4-Fluorobenzoyl chloride is used in the same manner as in Synthesis Example 1 except that 4-fluorobenzoyl chloride is used in place 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) In 30 g of DMF, 6.0 g of 4-fluoro-4′-methylthiobenzophenone obtained in Synthesis Example 3 was dissolved. 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. The crystals are washed three times with pure water and then toluene is distilled off to obtain crude crystals. The crude crystals are recrystallized with 40 g of ethanol to give 5.6 g of 4-methylthio-4'-phenylthiobenzophenone. The molar absorption 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 the above-mentioned Synthesis Example 2 except using -phenylthiobenzophenone, 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 Dissolve 5.0 g of phenyl-dimethoxymethane, 300 mg of camphorsulfonic acid and 4.3 g of triethyl orthoformate in 32.5 g of dehydrated ethanol and set this to 70 ° C. and stir for 5 hours while distilling off methanol in the solution with ethanol. . Thereafter, the reaction solution is cooled to room temperature, 50 g of a 5% by mass aqueous sodium hydrogencarbonate solution is added thereto, extracted with 50 g of ethyl acetate, and washed three times with pure water. Thereafter, ethyl acetate is distilled off, and the residue is purified by column chromatography (ethyl acetate / cyclohexane = 5/95 (volume ratio)) to obtain (4-methylthio) phenyl- (4′-phenylthio) phenyl-diethoxymethane 4 Get .6g. The sum of the Hammett substituent constant 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) Above, except that dehydrated ethylene glycol is used in place 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 of the Hammett substituent constant σ is 0.2 or less.

Synthesis Example 8 Synthesis of 2-methoxy-4′-methylthiobenzophenone (sensitizer compound A3) The same operation as in the above-mentioned Synthesis Example 1 except that 2-methoxybenzoyl chloride is used instead of 2,4-dimethoxybenzoyl chloride To obtain 2-methoxy-4'-methylthiobenzophenone. The molar absorption 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 By performing the same operation as in the above Synthesis Example 2 except that -methylthiobenzophenone is used, 2.7 g of 2- (2-methoxyphenyl) -2- (4'-methylthiophenyl) -dimethoxymethane is obtained. The sum of the Hammett substituent constant σ is −0.37.

Synthesis Example 10 Synthesis of 4- (4-methoxyphenyl) -4'-methylthiobenzophenone (sensitizer compound A4) Using 4- (4-methoxyphenyl) benzoyl chloride instead of 2,4-dimethoxybenzoyl chloride By performing the same operation as in Synthesis Example 1 except for the above, 5.2 g of 4- (4-methoxyphenyl) -4'-methylthiobenzophenone is obtained. The molar absorption 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) 4--in place of 2,4-dimethoxy-4′-methylthiobenzophenone (4-Methoxyphenyl) -phenyl- (4'-methylthiophenyl) -dimethoxymethane is obtained by the same procedure as in Synthesis Example 2 except that (4-methoxyphenyl) -4'-methylthiobenzophenone is used. Get 1g. 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. To this, 5.0 g of 4-methoxybenzoyl chloride is added dropwise over 30 minutes at 5 ° C. or less. Thereafter, after stirring at 5 ° C. for 2 hours, 15 g of pure water is added so as to be 25 ° C. or less, and stirring is further performed for 10 minutes. The organic layer is separated and washed with pure water, dichloromethane is distilled off, and the resulting residue is produced by recrystallization using 70 g of ethanol to give 2-methylthio-4,4'-dimethoxybenzophenone Get 6.5g. The molar absorption 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 in place of 2,4-dimethoxy-4′-methylthiobenzophenone 3.7 g of (2-methylthio-4-methoxy) phenyl- (4'-methoxy) phenyldimethoxymethane is obtained by the same procedure as in Synthesis Example 2 except that -4,4'-dimethoxybenzophenone is used. The sum of the Hammett substituent constant σ is −0.33.

Synthesis Example 14 Synthesis of 4- (2-vinyloxy) ethylthiobromobenzene A solution of 5.0 g of 4-bromothiophenol, 5.7 g of chloroethyl vinyl ether and 7.3 g of potassium carbonate dissolved in 20 g of acetone at reflux temperature Stir for 3 hours. Then, it cools to room temperature, adds 60 g of pure waters, and stirs for 5 minutes. To this is added 90 g of toluene for extraction, and the resultant is separated and washed 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 obtained by the same procedure as in Synthesis Example 1 except that 4- (2-vinyloxy) ethylthiobromobenzene is used instead of 4-bromothioanisole. Obtain 8.4 g of dimethoxybenzophenone). The molar absorption 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. Add 3 g, 0.44 g of pyridinium-p-toluenesulfonic acid to 30 g of acetone and stir at reflux temperature for 3 hours. Thereafter, the reaction solution is cooled to room temperature, 85 g of pure water is added, and after stirring for 5 minutes, extraction is performed 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, to which 1.9 g of triethylamine is added dropwise over 30 minutes so that the temperature does not exceed 20 ° C. After dropping, the mixture is stirred at 25 ° C. for 3 hours, 40 g of pure water is added, and the mixture is further stirred 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 absorption 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 4-[(2-methacryloxy) ethylthio] -phenyl by carrying out the same operation as in the above Synthesis Example 2 except using 4- (2-methacryloxy) ethylthio-2 ', 4'-dimethoxybenzophenone instead of 2.6 g of (2 ′, 4′-dimethoxyphenyl) dimethoxymethane are obtained. The sum of Hammett substituent constant σ is −0.56.

Synthesis Example 19 Synthesis of 4- (4-hydroxyphenylthio) -4′-methylthiobenzophenone (sensitizer Compound A7) The same as Synthesis Example 4 except that 4-hydroxybenzenethiol is used instead of thiophenol. The operation gives 5.8 g of 4- (4-hydroxyphenylthio) -4'-methylthiobenzophenone. The molar absorption coefficient at 365 nm in chloroform solvent is 3.01 × 10 ⁶ cm ² / mol. In addition, the molar absorption coefficient at 365 nm in an 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) in place of 2,4-dimethoxy-4′-methylthiobenzophenone By performing the same operation as in the above Synthesis Example 2 except using -hydroxyphenylthio) -4'-methylthiobenzophenone, 3.3 g of 4- (4-hydroxyphenylthio) phenyl-4'-methylthiophenyl-dimethoxymethane is obtained obtain. The sum of the Hammett substituent constant σ is 0.2 or less.

Synthesis Example 21 Synthesis of 4,4′-di (4-hydroxyphenylthio) benzophenone (sensitizer compound A8) In 20 g of DMF was dissolved 6.5 g of 4,4′-difluorobenzophenone, and 4-hydroxybenzene was dissolved therein. 11.3 g of thiol and 12.4 g of potassium carbonate are added and stirred at 70 ° C. for 2 hours. After stirring, 90 g of pure water is added, and stirring is further performed 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 vacuum dried to obtain 12.0 g of 4,4'-di (4-hydroxyphenylthio) benzophenone. The molar absorption 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 (4) instead of 2,4-dimethoxy-4′-methylthiobenzophenone 3.0 g of bis [4- (4-hydroxyphenylthio) phenyl] -dimethoxymethane is obtained by the same procedure as in Synthesis Example 2 except that 4-hydroxyphenylthio) benzophenone is used. The sum of the Hammett substituent constant 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 In 8.0 g of DMF, 2.0 g of -4'-methylthiophenyl-dimethoxymethane is dissolved, and 0.61 g of chloromethyl methyl ether and 1.1 g of potassium carbonate are added thereto, followed by stirring 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, and the organic layer is further washed twice with pure water. Thereafter, the organic solvent is distilled off, and the residue is purified by column chromatography (ethyl acetate / hexane = 1/2 (volume ratio)) to give 4- [4- (methoxymethoxy) phenylthio] phenyl-4'-methylthiophenyl- Obtain 1.2 g of dimethoxymethane. The sum of the Hammett substituent constant 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 In 12.0 g of methylene chloride, 2.0 g of thio) phenyl-4'-methylthiophenyl-dimethoxymethane is dissolved, and 1.6 g of di-tert-butyl dicarbonate, 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, and the organic layer is further washed twice with pure water. Thereafter, the organic solvent is distilled off, and the residue is purified by column chromatography (ethyl acetate / hexane = 1/3 (volume ratio)) to thereby obtain 4- [4- (t-butoxycarbonyloxy) phenylthio] phenyl-4′- 1.3 g of methylthiophenyl-dimethoxymethane are obtained. The sum of the Hammett substituent constant 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 a 35% aqueous hydrochloric acid solution are dissolved in 28 g of dehydrated dioxane. There, 2.73 g of cyclohexyl vinyl ether is dissolved in 2.80 g of dehydrated dioxane and added dropwise over 30 minutes to the polyhydroxystyrene solution. It stirs at 40 degreeC after dripping for 2 hours. After stirring, after cooling, 0.014 g of dimethylaminopyridine is added. Thereafter, the solution is dropped into 260 g of pure water to precipitate a copolymer. This is separated by filtration under reduced pressure, and the solid obtained is 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. In addition, the monomer ratio of the unit of the copolymer in this invention is not limited to the following.

Synthesis Example 25 Synthesis of Copolymer B 7.0 g of acetoxystyrene, 3.4 g of 2-methyladamantane-2-methacrylate, 0.022 g of butyl mercaptan and 0.40 g of dimethyl-2,2'-azobis (2-Methylpropionate) (AIBN) is deoxygenated by dissolving in 35 g of tetrahydrofuran (THF). The resultant is dropwise added over 4 hours to 20 g of THF which has been previously brought to a reflux temperature by nitrogenizing. After dropping, the mixture is stirred for 2 hours and then cooled to room temperature. The copolymer is precipitated by dropping this into a mixed solvent of 149 g of hexane and 12 g of THF. This is separated by filtration under reduced pressure and the solid obtained is washed with 52 g of hexane and then vacuum dried to obtain 10.3 g of copolymer B represented by the following formula as a white solid. The weight average molecular weight calculated | required by polystyrene conversion using gel permeation chromatography is 9200. In addition, the monomer ratio of the unit of the copolymer in this 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 are dissolved in 30 g of propylene glycol monomethyl ether and refluxed for 6 hours. Stir. After cooling to 25 ° C., the resulting solution is dropped into a mixed solution of 30 g of acetone and 30 g of pure water to precipitate a copolymer. This is separated by filtration under reduced pressure, and the solid obtained is washed twice with 30 g of pure water and then vacuum dried to obtain 4.3 g of a 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. In addition, the monomer ratio of the unit of the copolymer in this 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, 0.51 g of V601 is dissolved in 26 g of tetrahydrofuran, and vacuum degassing is performed. This is added dropwise over 4 hours to a flask in which 4 g of THF is refluxed. 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. The resultant is filtered, dispersed and washed twice with 37 g of hexane, and after filtration, it is vacuum-dried to obtain 7.7 g of the target copolymer D as a white powder. The weight average molecular weight determined by polystyrene conversion using gel permeation chromatography is 9700.

Synthesis Example 28 Synthesis of Copolymer E 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 2.3 g of (hydroxy) phenyl methacrylate, 0.13 g of butyl mercaptan and 0.58 g of V601 are dissolved in 12.5 g of tetrahydrofuran, and vacuum degassing is performed. After degassing, the reaction solution is dropped over 4 hours into a flask in which 4 g of THF is refluxed by nitrogen stream. After dropping, the mixture is stirred for 2 hours and then cooled to 25 ° C. After cooling, it is reprecipitated by dropwise addition in a mixed solvent consisting of 107 g of hexane and 11 g of tetrahydrofuran.
The resultant is filtered, dispersed and washed twice with 37 g of hexane, and after filtration, it is vacuum-dried to obtain 6.2 g of a target copolymer E as a white powder. The weight average molecular weight determined by polystyrene conversion using 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 2.3 g of (hydroxy) phenyl methacrylate, 0.49 g of 5-phenyldibenzothiophenium 1,1-difluoro-2- (2-methacryloyloxy) -ethanesulfonate, 0.13 g of butyl mercaptan and (4-hydroxy) 2.9 g of phenyl methacrylate and 0.56 g of dimethyl-2,2'-azobis (2-methyl propionate) (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 vacuum degassing is performed. After degassing, the reaction solution is dropped over 4 hours into a flask in which 4 g of THF is refluxed by nitrogen stream. After dropping, the mixture is stirred for 2 hours and then cooled to 25 ° C. After cooling, it is reprecipitated by dropwise addition in a mixed solvent consisting of 107 g of hexane and 11 g of tetrahydrofuran. The resultant is filtered, dispersed and washed twice with 37 g of hexane, and after filtration, it is vacuum-dried to obtain 6.6 g of a target 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 Dissolve 5.0 g of α-methacryloyloxy-γ-butyrolactone, 6.0 g of 2-methyladamantane-2-methacrylate and 0.51 g of V601 in 26 g of tetrahydrofuran, Perform vacuum degassing. This is added dropwise over 4 hours to a flask in which 4 g of THF is refluxed. 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 a target 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 vacuum degassing is performed. This is added dropwise over 4 hours to a flask in which 4 g of THF is refluxed. 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 a target copolymer H as a white powder. The weight average molecular weight determined by polystyrene conversion using gel permeation chromatography is 8800.

<Sample Preparation 1 for Sensitivity Evaluation (“Evaluation Sample”)>
Evaluation samples 1 to 20 are prepared as follows. Any of a resin selected from 7000 mg of cyclohexanone, 500 mg of the copolymers 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) Fluorobutanesulfonate (DPI-Nf) or phenyldibenzothionium-nonafluorobutanesulfonate (PBpS-Nf) 0.043 mmol and precursor compounds B1-3, B9 and B10 as photosensitizer precursors and 2 as a comparison compound Or 2-diphenyl-1,3-dioxolane (compound C1) (the sum of Hammett's substituent constant σ is 0, and the molar absorption coefficient at 365 nm in chloroform solvent is 6.3 × 10 ⁴ cm ² / mol) With 0.043 mmol or less, respectively. A sample is prepared by adding 0.0043 mmol of trioctylamine as-, 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 evaluation sample 1 to 20 is coated on a Si wafer previously treated with hexamethyldisilazane (HMDS), spin coated, and heated at 110 ° C. to obtain a resist film with a film thickness of 100 nm.
Next, the evaluation sample resist film is exposed at different exposure amounts so that a 1: 1 line and space pattern having a line width of 100 nm can be formed by a 30 keV EB lithography system. Thereafter, the entire surface of the wafer is irradiated with ultraviolet light using a UV light having an emission line of 365 nm. Then, heat on a hot plate at 110 ° C. for 1 minute. After heating, develop for 1 minute using a developer (product name: NMD-3, 2.38 mass% tetramethyl ammonium hydroxide, manufactured by Tokyo Ohka Kogyo Co., Ltd.), develop, 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 off is taken as E size (minimum exposure amount). Table 2 shows the results of evaluating the minimum exposure amount as the 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 are the EB minimum by UV irradiation after EB irradiation. The amount of exposure decreases. Thereby, in the resist compositions of Examples 1 to 9 and 13 to 16, the generation of acid is improved by the photosensitization of the photosensitizer generated from the photosensitizer precursor, and the sensitivity is improved. I understand. Further, from the comparison of Example 4 and Comparative Example 1, and Example 7 and Comparative Example 2, the acid generation efficiency by EB is improved more than the resist having no hydroxy group by including a compound having a hydroxy group in the resist. It is understood that the sensitivity is increased by doing this.

  From the comparison of Examples 1 to 4 and Comparative Example 1, even if the same precursor compound B1 is used as a photosensitizer precursor, copolymers A and C having a large proportion of hydroxy groups, particularly hydroxyaryl groups in the composition. Has a high efficiency of photosensitization. The reason for this is that, in addition to the hydroxyaryl group acting as an excellent proton donor among the hydroxyl groups, the presence of many hydroxy groups in the copolymer increases the polarity of the resist, which is generated from the photosensitizer precursor. It is considered that the stabilization of the photosensitizer causes the wavelength of the absorption to be long and the molar absorption coefficient at 365 nm becomes large. Furthermore, from the comparison of Examples 4 and 5, the effect of UV irradiation is that the molar absorption coefficient of the photosensitizer generated from the photosensitizer precursor is large if the sum of Hammett substituent constant σ is 0.2 or less There is a tendency to increase sensitivity.

  In addition, as shown in Examples 10 and 11, when the precursor compound B8 is bound in the polymer, the efficiency of acid generation by UV irradiation is higher than in Examples 1-9. This is because the generated photosensitizer is uniformly dispersed in the resist, and the reaction probability of the photosensitizer and the photoacid generator is higher than when the photosensitizer precursor is mixed in the resist. It is considered to be. When precursor compound B8 and PAG are bound in the polymer as shown in Example 12, the efficiency of acid generation by UV irradiation is higher than in Examples 10 and 11.

  Comparing Examples 5, 13 and 14, 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. As with the sensitizer compounds A7 and A8 generated from the precursor compounds B9 and B10, the increase of the molar absorption coefficient at 365 nm by introducing a 4-hydroxyphenylthio group and the electron donating ability by the phenolic hydroxyl group It is considered to be due to the improvement. Furthermore, it is thought that the acid generation efficiency of the photosensitization which arises between a photosensitizer and an acid generator improved by the phenolic hydroxyl group of a photosensitizer becoming a proton source.

The compound C1 added in Comparative Examples 3 and 4 has an extremely high UV sensitization efficiency because the sum of Hammett substituent constants σ is 0 or more and the molar absorption coefficient at 365 nm is as low as 6.3 × 10 ⁴ cm ² / mol. In the case of 200 mJ / cm ² UV irradiation, the amount of acid generation did not improve and the sensitivity was not increased.
From the above, it is considered that a highly sensitive photosensitizer precursor can be obtained by adding an electron donating group to the compound and increasing the molar absorption coefficient at 365 nm.

Sample Preparation 2 for Sensitivity Evaluation ("Evaluation Sample")>
Evaluation samples 16 to 25 are prepared as follows. To 7,000 mg of cyclohexanone, 500 mg of the above copolymer A or H, diphenyliodonium nonafluorobutanesulfonate (DPI-Nf) as a photoacid generator (PAG), phenyldibenzothionium nonafluorobutanesulfonate (PBpS-Nf) 4-phenylthio) phenyldiphenylsulfonium-nonafluorobutanesulfonate (PSDPS-Nf) 0.043 mmol and sensitizer compounds A1, A2, A7 and A8 as photosensitizers are each added 0.043 mmol or There is no addition, and a sample is prepared by adding trioctylamine as a quencher at a ratio of 0.0043 mmol. Details of the prepared samples are shown in Table 3.

<Sample evaluation 2>
Each of the evaluation samples 21 to 32 is coated on a hexamethyldisilazane (Si wafer subjected to HMDS treatment) in advance, spin-coated, and heated at 110 ° C. to obtain a resist film having a film thickness of 500 nm.
Next, the evaluation sample resist film is exposed by changing the exposure amount by a UV exposure apparatus having a bright line of 365 nm through a 1: 1 line and space pattern mask with a half pitch of 2 μm of line width. Then, heat on a hot plate at 110 ° C. for 1 minute.
After heating, develop for 1 minute using a developer (product name: NMD-3, 2.38 mass% tetramethyl ammonium hydroxide, manufactured by Tokyo Ohka Kogyo Co., Ltd.), develop, 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 off is taken as E size (minimum exposure amount). Table 4 shows the results of evaluating the minimum exposure amount as the sensitivity.

  As shown in Comparative Example 5, PBP-Nf does not generate an acid because there is no UV absorption at 365 nm, but Examples 17, 18, 21 using a resist composition in which a photosensitizer was mixed in one embodiment of the present invention , 24 and 25 can be acid-generated because the added photosensitizer absorbs light at the time of UV irradiation to sensitize the acid generator. Furthermore, it is understood that the sensitivity is higher than that of Comparative Examples 6 and 7 in which any of the examples is mixed with an acid generator having a UV absorption at 365 nm. As a result, in the resist compositions of Examples 17 to 25, the acid generation is improved and the sensitivity is improved. According to the results of Example 20 and Comparative Example 6, and Example 23 and Comparative Example 7, the irradiation wavelength is Even in the case of an acid generator having UV absorption, it is understood that the sensitivity is enhanced by the effect of the photosensitizer.

  When Examples 17, 18, 24 and 25 are compared, it is understood that the larger the molar absorption coefficient of the added sensitizer compound, the higher the sensitivity. Further, it is considered that Examples 24 and 25 are more sensitive because the electron donating property is improved by introducing a hydroxy group to the thioaryl structure as in the sensitizer compounds A7 and A8. Furthermore, it is considered that the effect of the acid generation efficiency in the sensitization reaction occurring between the photosensitizer and the acid generator was also improved by the fact that the phenolic hydroxyl group of the sensitizer compound is a proton source.

  According to some aspects of the present invention, it is possible to provide a resist composition comprising a photosensitizer precursor for improving acid generation efficiency and forming a photoresist with high sensitivity, high resolution and high LWR characteristics. .

Claims (13)

A photosensitizer precursor represented by the following general formula (1),
A photoacid generator,
A hydroxy group-containing compound,
An acid reactive compound, and a resist composition.
(1)
(In the above 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, an arylthio group and a thioalkoxyphenyl group,
X is any one 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 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,
The R ³ and R ⁴ may be bonded to each other to form a ring structure with two Y in the formula,
At least one carbon-carbon single bond in the alkyl group possessed by R ¹ , R ² , R ³ and R ⁴ may be replaced by a carbon-carbon double bond or a carbon-carbon triple bond,
At least one of the methylene groups in the alkyl group possessed by R ¹ , R ² , R ³ and R ⁴ may be replaced by a divalent hetero atom-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 absorption coefficient at 365 nm after treating the photosensitizer precursor with an acid is 1.0 × 10 ⁵ cm ² / mol or more. The resist composition according to any one of claims 1 to 3, wherein Ar ¹ and / or Ar ² have 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 the Ar ² further have 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 the Ar ² and / or the Ar ² . The resist composition according to any one of claims 1 to 6, wherein the R ¹ is bonded to the ortho position or the para position of the Ar ¹ . Wherein when X is sulfur atom or oxygen atom, wherein X is a resist composition according to any one of claims 1 to 7 attached in the ortho or para position of the Ar ^2.   9. The method according to claim 1, wherein 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 contained as respective units bound 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 control agent, a surfactant, a dissolution inhibitor and a solvent. Applying the resist composition according to any one of claims 1 to 10 onto a substrate to form a resist film;
Irradiating the resist film with a first active energy ray;
Applying a second active energy ray to the resist film after the first active energy ray irradiation;
Developing the resist film after the irradiation with the second active energy ray to obtain a pattern. The first active energy beam is a particle beam or an electromagnetic wave,
When the first active energy beam is a particle beam, the second active energy beam is an electromagnetic wave, and when the first active energy beam is an electromagnetic wave, the second active energy beam is the electromagnetic wave of the first active energy beam. The method according to claim 11, wherein the electromagnetic wave is longer than the wavelength of.   The method of manufacturing a device according to claim 11, wherein the first active energy ray is an electron beam or an extreme ultraviolet ray.