TW201807491A - Resist composition and method for producing device using same - Google Patents

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

Method for manufacturing resist composition and device using same

Several aspects of this invention are related with the composition which can be used for forming a resist pattern, and the manufacturing method of the apparatus using the same.

For semiconductor devices, for example, high-integration circuit elements typified by DRAM, etc., further high-density, high-integration, and high-speed are urgently desired. Accompanying this, in various electronic device manufacturing fields, the establishment of a micron-level microfabrication technology, such as the development of photolithography technology for forming fine patterns, has become increasingly strict. In photolithography, in order to form a fine pattern, it is necessary to improve the resolution. Here, the resolution (R) of the reduced projection exposure device is expressed by the Rayleigh formula R = k‧λ / NA (where λ is the wavelength of the exposure light, NA is the number of lens openings, and k is the process factor), so By reducing the wavelength λ of the active energy ray (exposure light) used when forming the resist pattern, the resolution is improved.

As a photoresist suitable for a short wavelength, a chemically amplified photoresist has been proposed (Patent Documents 1 to 3). The chemically amplified photoresist is characterized in that by irradiating light with an exposure light, an acid is generated as a photoacid generator containing a component, and the acid undergoes an acid-catalyzed reaction with a resist compound or the like after heat treatment after exposure.

With the miniaturization of semiconductor devices, the requirements for EUV lithography using EUV (Extreme Ultra Violet: 13.5 nm) light as the exposure light are increasing. However, the biggest disadvantage of EUV lithography is the insufficient output of EUV light sources. Therefore, a high-sensitivity photoresist is required, but there is a trade-off relationship between sensitivity, resolution, and LWR (Line Width Roughness). Therefore, when sensitivity is increased, the resolution is reduced and the roughness is increased. The problem.

[Existing technical literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 10-7650

[Patent Document 2] Japanese Patent Laid-Open No. 2003-327572

[Patent Document 3] Japanese Patent Laid-Open No. 2008-7410

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

An object of one of several aspects of the present invention is to provide a resist composition capable of improving acid generation efficiency. In addition, another object of some aspects of the present invention is to provide a method for manufacturing a device using the above-mentioned resist suitable for use as a photoresist composition satisfying high sensitivity, high resolution, and high LWR characteristics.组合 物。 Composition.

In order to solve the above problems, the present inventors have conducted intensive studies and found that by using a photoresist precursor containing a photosensitizer that can form a photosensitizer due to acid dissociation, a photoacid generator, a hydroxyl group-containing compound, and an acid-reactive compound, As a chemically amplified resist composition, the agent composition can increase the efficiency of acid generation.

More specifically, in the pattern formation using a chemically amplified photoresist containing a photoacid generator, a composition containing a photosensitizer precursor, a photoacid generator, a hydroxyl-containing compound, and an acid-reactive compound is used. As a chemically amplified photoresist composition, for example, an acid is generated from a photoacid generator by irradiating a first active energy ray such as EUV light or an electron beam (EB), and the photosensitizer precursor is generated by the acid. The acid is dissociated to form a photosensitizer, and the photosensitizer is further irradiated with a second light by UV light or the like, thereby causing electrons to move to the photoacid generator, and the acid generation efficiency is improved.

One embodiment of the present invention is a resist composition containing a photosensitizer precursor, a photoacid generator, a hydroxyl-containing compound, and an acid-reactive compound 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, and R ¹ is selected from the group consisting of a thioalkoxy group, an arylthio group, and a thioalkyl group which may have a substituent. In any group of the oxyphenyl group, X is any one selected from the group consisting of a sulfur atom, an oxygen atom, and a direct bond, and R ² is an alkyl group and an aryl group which may have a substituent. In each of Y, Y is independently any one of an oxygen atom and a sulfur atom, and R ³ and R ⁴ are each independently a linear, branched, or cyclic alkyl group which may have a substituent, The above R ³ and R ⁴ may be bonded to each other to form a ring structure with two Y in the formula, and at least one carbon-carbon single bond in the alkyl group of R ¹ , R ² , R ³ and R ⁴ may be carbon -Carbon double bond or carbon-carbon triple bond substitution, at least one methylene group in the alkyl group possessed by R ¹ , R ² , R ^3, and R ⁴ may be substituted by a divalent hetero atom-containing group.)

The resist composition of one aspect of the present invention can improve the acid generation efficiency of the photoacid generator, and has high sensitivity, high resolution, and high LWR characteristics.

The present invention is explained in detail below.

<1> Photosensitizer precursor

The photosensitizer precursor in one aspect of the present invention is characterized 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, and R ¹ is selected from the group consisting of a thioalkoxy group, an arylthio group, and a thioalkoxy group which may have a substituent. In any one of the groups consisting of phenyl groups, X is any one selected from the group consisting of a sulfur atom, an oxygen atom, and a direct bond, and R ² is an alkyl group or an aryl group which may have a substituent. In any case, Y is each independently an oxygen atom and a sulfur atom, and R ³ and R ⁴ are each independently a linear, branched, or cyclic alkyl group which may have a substituent. ³ and R ⁴ may be bonded to each other to form a ring structure with two Y in the formula, and at least one carbon-carbon single bond in the alkyl group of R ¹ , R ² , R ³ and R ⁴ may be carbon-carbon The double bond or the carbon-carbon triple bond is substituted, and at least one methylene group in the alkyl group of R ¹ , R ² , R ^3, and R ⁴ may be substituted with a divalent hetero atom-containing group.

In the photosensitizer precursor according to one aspect of the present invention, the sum of Hammett constant σ is preferably 0.2 or less.

In the present invention, the total of the Hammett's substituent constant σ refers to a group bonded to a quaternary carbon bonded to two Y, Ar ¹ , and Ar ² in the general formula (1), Sum of the Hammett's substituent constant σ of each substituent bonded to each of Ar ¹ and Ar ² .

The Hammett substituent constant σ refers to the value (σ p value, σ m value) obtained from the empirical rule proposed by LP Hammett in 1935 in order to quantitatively discuss the effect of substituents on the reaction or equilibrium of benzene derivatives. , Σ o value).

The values of the σ p value and the σ m value in the substituent constants obtained from Hammy's law are disclosed in detail in, for example, JADean, "Lange's Handbook of Chemistry" 12th edition, 1979 (McGraw-Hill), "Sector" Supplement, No. 122, pages 96-103, 1979 (Nanguangtang).

In addition, σ o values studied in terms of the effects of steric hindrance are disclosed in detail in Nuclear magnetic resonance studies of ortho-substituted phenols in dimethyl sulfoxide solutions. Electronic effects of orthos J. Am. Chem. Soc., 1969, 91 ( 2), pp 379-388, by M. Thomas and James G. Traynham.

The total of the Hammett's substituent constant σ of the photosensitizer precursor is preferably 0.2 or less, and more preferably -0.01 or less. In addition, it is preferably -3.00 or more. 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. When the sum of the Hammett substituent constant σ of the substituent in Ar ¹ and the Hammett substituent constant σ of the substituent in Ar ² is 0.2 or less, the Hammett substitution of the photosensitizer precursor is performed. The total of the basis constants σ is 0.2 or less.

If the sum of the Hammett's substituent constants σ of the photosensitizer precursor is within the above range, it is electron-donating. When the photosensitizer precursor undergoes acid dissociation and becomes a photosensitizer, the acid production efficiency of the photoacid generator can be improved . In order to make the sum of the Hammett substituent constants σ 0.2 or less, an electron-donating group or an electron-withdrawing substituent is appropriately selected according to the Hammett substituent constant σ disclosed above, and the above-mentioned Ar ¹ and Ar ^{2 are introduced} . The electron group can be introduced at an appropriate position to adjust the Hammett substituent constant σ.

Ar ¹ and Ar ² in the formula (1) are each a phenylene group, and may each have a substituent other than R ¹ or -XR ² (hereinafter, the substituents of Ar ¹ and Ar ² are referred to as "first substituents""). In addition, from the viewpoint of synthesis, it is preferable that Ar ¹ and Ar ^{2 are} not bonded to form a ring, either directly or indirectly.

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, and an aromatic sulfur. And thioalkoxyphenyl. Examples of the first substituent include a long-chain alkoxy group having a polyethylene glycol chain (-(CH ₂ CH ₂ O) _n- ). When the first substituent is bonded to the para position of Ar ¹ or Ar ² , it may have a hydroxyl group as the first substituent.

In addition, in the present invention, the substitution positions such as the "para" of Ar ¹ or Ar ² are bonded to the quaternary carbon bonded to two Y, Ar ¹ , and Ar ² in the above formula (1). Position in terms of groups. Not only the first substituent, but also other groups, the reference of the substitution position such as "para-position" is also relative to the position of the group bonded to the quaternary carbon.

The alkyl group as the first substituent is not particularly limited, and examples include methyl, ethyl, propyl, butyl, pentyl, hexyl, isopropyl, tert-butyl, cyclohexyl, and adamantyl. 1 ~ 20 Linear, branched and cyclic alkyl. The alkoxy group as the first substituent is not particularly limited, and examples thereof include alkoxy groups 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 thioalkoxy group, arylthio group, and thioalkoxyphenyl group with R ¹ described later. Same group.

When the first substituent is an alkoxy group, an alkoxyphenyl group, a thioalkoxy group, an arylthio group, and a thioalkoxyphenyl group, it is preferably ortho to Ar ¹ and Ar ² , that is, a phenylene group and / Or para-bond. In this case, the total number of the first substituents that Ar ¹ and Ar ² have is preferably 3 or less.

R ¹ in the formula (1) is any ^one selected from the group consisting of a thioalkoxy group, an arylthio group, and a thioalkoxyphenyl group which may have a substituent.

As the thioalkoxy group of R ¹ , specifically, a thio group having 1 to 20 carbon atoms such as a thiomethoxy group, a thioethoxy group, a thio-n-propoxy group, and a thio-n-butoxy group is preferable. The alkoxy group is more preferably a thioalkoxy group having 1 to 12 carbon atoms.

Specific examples of the arylthio group of R ¹ include a phenylthio group and a naphthylthio group.

Specific examples of the thioalkoxyphenyl group of R ¹ include a thiomethoxyphenyl group, a thioethoxyphenyl group, a thiopropoxyphenyl group, and a thiobutoxybenzene group. A phenyl group having a thioalkoxy group having 1 to 20 carbon atoms, such as a group, is more preferably a phenyl group having a thioalkoxy group having 1 to 12 carbon atoms. The substitution position of R ¹ as a thioalkoxy group bonded to a phenylene group is not particularly limited, and from the viewpoint of improving the electron donating property and the molar absorption coefficient at 365 nm, it is preferably a para position.

The R ¹ is preferably bonded to the ortho or para position of the Ar ¹ phenylene group.

R ² in the formula (1) is any one of an alkyl group and an aryl group which may have a substituent.

Examples of the alkyl group of R ² include straight-chain and branched carbon atoms having 1 to 20 carbon atoms such as methyl, ethyl, propyl, butyl, pentyl, hexyl, isopropyl, tert-butyl, and cyclohexyl. Chain and cyclic alkyl.

Examples of the aryl group of R ² include a phenyl group and a naphthyl group.

R ¹ and R ² in the formula (1) may have a substituent as the substituent (hereinafter, the substituents of R ¹ and R ² are referred to as "second substituent"), and are not particularly limited, except for the first Examples of the substituent include a nitro group, a sulfonyl group, a carbonyl group, and a hydroxyl group. In particular, when at least one of R ¹ and R ² is an aryl group, and the aryl group has a second substituent, by using a nitro group, a sulfofluorenyl group, a carbonyl group, a hydroxyl group, and the like as the second substituent, the number can be increased. A molar absorption coefficient of 365 nm is preferred.

As will be mentioned later, a polymerizable group may be introduced into the above-mentioned R ¹ or R ² and used as a polymer having a sensitizing effect after polymerization. That is, the polymer containing a part having a function as a photosensitizer precursor as a unit is also a photosensitizer precursor in one embodiment of the present invention, and the second substituent may have a structure containing a polymer main chain. Examples of the polymerizable group include (meth) acrylic fluorenyloxy, epoxy, and vinyl.

In addition, "(meth) acrylfluorenyl" represents acrylfluorenyl and methacrylfluorenyl.

When X in the formula (1) is an oxygen atom or a sulfur atom, the X is preferably ortho or para to Ar ² . When the X is a direct bond, the X is preferably ortho or para to Ar ² .

At least one carbon-carbon single bond in the alkyl group possessed by R ¹ , R ² , the first substituent and the second substituent may be substituted by a carbon-carbon double bond or a carbon-carbon triple bond. In addition, at least one methylene group in the alkyl group possessed by R ¹ , R ² , the first substituent and the second substituent may be substituted with a divalent hetero atom-containing group.

The divalent heteroatom-containing group is selected from the group consisting of -O-, -CO-, -COO-, -OCO-, -O-CO-O-, -NHCO-, -CONH-, -NH-CO. -O-, -O-CO-NH-, -NH-, -N (R)-, -N (Ar)-, -S-, -SO- and -SO _2- Or divalent organic group. Further, among R ¹ , R ² , the above-mentioned first and second substituents, it is preferred that there is no continuous connection of heteroatoms such as -OO- and -SS-.

Examples of R include the same groups as those exemplified for the first substituent.

Examples of Ar include the same groups as those of the aryl group of R ² .

The total number of carbon atoms of R ¹ in the formula (1) is not particularly limited, and the total number of carbon atoms is preferably 1 to 20 regardless of the presence or absence of a substituent of R ¹ . The total number of carbon atoms of R ² in the formula (1) is not particularly limited, and the total number of carbon atoms is preferably 1 to 20 regardless of the presence or absence of a substituent of R ² .

The above-mentioned photosensitizer precursor is a polymer, preferably comprising removing the total number of carbon atoms to become part of the polymer backbone of the second group of substituents R ¹ and R ² is 1 to 20.

R ¹ , R ² , the first substituent and the second substituent may have an acid-dissociable group. The acid-dissociable group may be a protecting group that is deprotected by the action of an acid, and examples thereof include tert-butoxycarbonyloxy, methoxymethoxy, ethoxymethoxy, and trimethyl Methylsilyloxy, tetrahydropyranyloxy, 1-ethoxyethoxy and the like. 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 the acid, and the solubility comparison between the exposed portion and the unexposed portion is easily obtained. Preferred.

Y is each independently 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. Examples of the alkyl group of R ³ and R ⁴ include a straight chain having 1 to 20 carbon atoms such as methyl, ethyl, propyl, butyl, pentyl, hexyl, isopropyl, tert-butyl, and cyclohexyl. Shaped, branched and cyclic alkyl.

From the viewpoint of synthesis, it is preferable that R ³ and R ^{4 are the} same.

In addition, in the present invention, when R ³ and R ⁴ are the groups exemplified above, the photosensitizer precursor may have a carbonyl group due to acid deprotection.

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 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. n is not particularly limited as long as it is 2 or more, and is preferably 8 or less in terms of ease of synthesis. In addition, from the viewpoint of the activation energy of a cyclic acetal protecting group described later, n is preferably 3 or more. R ⁵ and R ⁶ are groups corresponding to a group in which R ³ and R ⁴ in the above formula (1) are bonded to each other to form a ring.

It is known that the activation energy of acyclic acetals is generally lower than that of cyclic acetals, and the hydrolysis of cyclic acetal compounds high speed. In addition, among cyclic acetal compounds, the activation energy of a 5-membered ring structure such as 1,3-dioxolane is high and stable, while the 1,3-dioxane structure and 1,3-dioxane Cycloheptane, which has a 6-membered or more structure, has low activation energy. Relative comparative values of hydrolysis rates due to differences in the structure of the cyclic acetal compound are described, for example, in 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 for the acetal protecting group. This is because the photosensitizer precursor is easily converted into a photosensitizer by a deprotection reaction of the acetal. From the viewpoint of the activation energy of the acetal protecting group, the 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), when 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 preferably-(CH ₂ ) _n -where n is 3 or more. .

R ³ and R ⁴ in the 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"), there is no particular limitation, except for the above-mentioned Examples of the 2 substituent include aryl groups such as phenyl and naphthyl.

At least one carbon-carbon single bond in the alkyl group possessed by R ³ , R ⁴ and the third substituent may be substituted by a carbon-carbon double bond or a carbon-carbon triple bond. In addition, at least one methylene group in the alkyl group possessed by R ³ , R ^4, and the third substituent may be substituted with the divalent hetero atom-containing group.

The total number of carbon atoms of R ³ and R ⁴ in the formula (1) is not particularly limited, and the photosensitizer precursor may be a constituent component of a polymer. Regardless of whether or not R ³ or R ⁴ is substituted, the total number of carbon atoms is preferably 1 to 20, respectively. In the formula (2), R ⁵ and R ⁶ may have the above-mentioned third substituent which is the same as the above-mentioned R ³ and R ⁴ . A polymerizable group may be introduced into R ³ or R ⁴ and used as a polymer that imparts sensitization after polymerization. That is, when the photosensitizer precursor according to one embodiment of the present invention is a polymer containing a moiety having a photosensitizer precursor function as a unit, the third substituent may have a polymer-containing host instead of the second substituent. The composition of the chain.

In addition, the total number of carbon atoms of R ³ and R ⁴ is preferably 1 to 20. When the photosensitizer precursor is a polymer, the total number of carbon atoms of R ³ and R ⁴ except for the polymer main chain-containing portion that becomes the third substituent is preferably 1 to 20.

The photosensitizer having a carbonyl group generated after the photosensitizer precursor is acid-treated, that is, when the photosensitizer precursor is deprotected by an acid, preferably has a molar absorption coefficient of 1.0 × 10 ⁵ cm ² / mol or more at 365 nm. Although the molar absorption coefficient is preferably high at 365 nm, the actual value is 1.0 × 10 ¹⁰ cm ² / mol or less. In order to make the molar absorption coefficient into the above range, for example, the photosensitizer precursor may have at least one selected from the group consisting of a thioalkoxy group, an arylthio group, and a thioalkoxyphenyl group, or It has a configuration of any one of two or more alkoxy groups and aryloxy groups.

In the present invention, the molar absorption coefficient is a value at 365 nm in a chloroform solvent or an acetonitrile solvent measured using a UV-VIS absorbance spectrophotometer using chloroform or acetonitrile as a solvent. In several aspects of the present invention, the molar absorption coefficient of the photosensitizer having a carbonyl group can reach the above-mentioned range whether it is a chloroform solvent or an acetonitrile solvent.

In addition, the photosensitizer precursor in one aspect of the present invention is selected from the group consisting of -YR ³ and -YR ⁴ or -YR ^{3 in the} entire photosensitizer precursor in terms of easy synthesis and light absorption characteristics. Groups other than -R ⁴ -Y- in the group consisting of thioalkoxy, arylthio, alkoxyphenyl, thioalkoxyphenyl, alkoxy and aryloxy are preferred It is 4 or less.

As a preferable example of the photosensitizer precursor represented by said Formula (1), the following photosensitizer precursor is illustrated, for example. In the following examples, the part indicated by the parentheses represents a unit of the polymer. The photosensitizer precursor in several aspects of this invention is not limited to this.

[Chemical 4]

[Chemical 5]

<2> Synthesis method of photosensitizer precursor

A method for synthesizing a photosensitizer precursor in one embodiment of the present invention will be described. In the present invention, the synthesis method 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, an alkyl group selected from alkoxybenzyl chloride, alkyl benzyl chloride, thioalkoxybenzyl chloride, thioalkyl benzyl chloride, and their alkyl groups selected from the group -XR ^{2 is} used. One of the group consisting of the compound after the aryl group becomes an aryl group; and a halogenated benzene having an R ¹ group, a benzophenone derivative is obtained by a Grignard reaction. Next, the benzophenone derivative, and orthoesters such as alcohol and a dehydrating agent such as trialkyl orthoformate (R ³ , R ⁴ = alkyl) used as needed, are reacted 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 formula (3) obtained above and 1,3-propanediol can be mixed with camphorsulfonic acid or the like. It is obtained by reacting at 0 to 100 ° C for 1 to 120 hours in the presence of an 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) and methyl mercaptan obtained in the above can be obtained in a way It can be obtained by reacting in the presence of silicic acid at -78 ° C to 0 ° C for 1 to 120 hours.

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 formula (3) and 3-mercapto-1-propanol can be chlorinated by the above-mentioned method. It is obtained by reacting for 1 to 120 hours at 0 to 100 ° C in the presence of a Lewis acid such as zirconium (IV).

When the photosensitizer precursor in one embodiment of the present invention has a structure represented by the following formula (7), It is obtained by reacting the derivative represented by the above formula (3) and methyl mercaptan obtained in the above with a Lewis acid such as boron trichloride at 0 to 100 ° C for 1 to 120 hours.

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

The photosensitizer precursor according to one embodiment of the present invention can efficiently perform an acetalization reaction by having a specific structure. Ar ¹ and Ar ² preferably do not have a ring structure formed by bonding a divalent group to the quaternary carbon. As a reason, when Ar ¹ and Ar ² have a ring structure via a divalent group and the above-mentioned quaternary carbon, for example, when having a skeleton such as thioxanthone, the acetalization reaction may be difficult to proceed efficiently. Therefore, from the viewpoint of synthesis, it is preferable that Ar ¹ and Ar ² do not have a ring structure formed by direct bonding or a ring structure formed by bonding with a quaternary carbon through a divalent group.

<3> Photoacid generator

The acid generator in one embodiment of the present invention is not particularly limited as long as it is an acid generator generally used in a chemically amplified resist composition, and examples thereof include onium salt compounds and N-sulfonyloxyimine Compounds, halogen-containing compounds, diazolone compounds, and the like. The photoacid generator can be used alone or in combination of two or more. Considering the sensitivity of EUV and EB, the electron accepting property is preferably high, and the molar absorption coefficient at 365 nm is more preferably 1.0 × 10 ⁴ cm ² / mol or less.

Examples of the onium salt compound include a sulfonium salt, an iodonium salt, a sulfonium salt, a diazonium salt, and a pyridinium salt. Examples of the sulfonium salt and iodonium salt include the salts described in WO2011 / 093139. Specific examples include a photoacid generator represented by the following formula (9) or (10), but are not limited thereto.

R ^a COOR ^b SO ₃ ^- M ⁺ (9)

In the formula (9), R ^a represents a monovalent organic group having 1 to 200 carbon atoms which may have a substituent, and R ^b represents a hydrocarbon group in which a part of hydrogen atoms may be substituted with fluorine atoms. M ⁺ represents a counter cation.

R ^a COOCH ₂ CH ₂ CFHCF ₂ SO ₃ ^- M ⁺ (10)

In the 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 photoacid generator may be added to the resist composition as a low molecular weight component, or may be contained as a unit of a polymer. That is, the polymer may be contained in the polymer as a unit that is bonded to the polymer main chain at an arbitrary position of the photoacid generator. For example, when the photoacid generator is a sulfonium salt, it is preferable to have an atomic bond directly bonded to the polymer main chain or via a linking group instead of one H of the substituent in the sulfonium salt.

<4> hydroxyl-containing compounds

The hydroxy-containing compound in one embodiment of the present invention is not particularly limited as long as the hydrogen of the hydroxy group becomes a hydrogen supply source when the photoacid generator is decomposed. By including the hydroxyl-containing compound in the resist composition, the acid generation efficiency of the photoacid generator can be improved, and by adding a hydroxyl group, it is possible to reduce the ionization potential as compared with a case where the hydroxyl group is not present.

Examples of the hydroxy-containing compound include those derived from hydroxystyrene, hydroxyvinylnaphthalene, hydroxyphenyl acrylate, hydroxyphenyl methacrylate, hydroxynaphthyl acrylate, hydroxynorbornene acrylate, and hydroxybenzene. A polymer of units such as norbornene methacrylate, hydroxynaphthyl methacrylate, hydroxyadamantyl acrylate, and hydroxyadamantane methacrylate; bisphenol, TrisP-PA (manufactured by Honshu Chemical Industry Co., Ltd.) Polyphenol compounds such as aromatic hydrocarbons; etc. Among them, polymers containing units derived from hydroxystyrene, hydroxyvinylnaphthalene, hydroxyphenyl acrylate, hydroxyphenyl methacrylate, hydroxynaphthyl acrylate, hydroxynaphthyl methacrylate, and the like are preferred. Examples of the hydroxyaryl-containing compound include a polymer having a unit represented by the following formula (11).

[Chemical 13]

In the above formula (11), Ar ³ is an arylene group, R ⁷ is a hydrogen atom or a hydrocarbon group, and L represents a carbonyloxy group or a direct bond.

The arylene group of Ar ³ may have a hydroxyl group in addition to the hydroxyl group disclosed in Formula (11). As the arylene group of Ar ^3, an arylene group having 6 to 14 carbon atoms which may have a substituent other than a hydroxyl group is preferable, a phenylene group or a naphthylene group which may have a substituent group is more preferable, and it is more preferable that Substituent phenylene.

The hydrocarbon group of 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.

As said hydroxyaryl group containing compound, the polymer which has a unit represented by a following formula is mentioned preferably, but it is not limited to this.

<5> acid-reactive compounds

Examples of the acid-reactive compound include a compound having a protective group deprotected by an acid, a compound having a polymerizable group polymerized by an acid, and a cross-linking agent having a cross-linking effect by an acid.

The compound having a protective group deprotected by an acid means a compound that, for example, when a composition is used as a resist composition, a gene acid is protected and deprotected to generate a polar group, thereby changing the solubility of the developer. For example, in the case of developing with an aqueous system such as an alkaline developer, although it shows insolubility to the alkaline developer, the acid generated by the photoacid generator by exposure causes deprotection of the protective group in the exposed portion, thereby protecting the alkali. A developer-soluble compound.

In the present invention, the developer is not limited to an alkaline developer, and may be a neutral developer or an organic solvent for development. Therefore, when an organic solvent developing solution is used, a compound having a protective group deprotected by an acid is a compound that removes the protective group by deprotection by exposing the acid generated by the photoacid generator by exposure, thereby preventing A compound in which the solubility of an organic solvent developer is reduced.

Examples of the polar group include a hydroxyl group and a carboxyl group, an amino group and a sulfo group.

Specific examples of the protective group deprotected by an acid include an ester group, an acetal group, a tetrahydropyranyl group, a silyloxy group, a benzyloxy group, and the like. As the compound having the protective group, a compound having a styrene skeleton, a methacrylate or an acrylate skeleton modified by these protective groups is preferably used.

The compound having a protective group deprotected by an acid may be a low-molecular compound containing a protective group or a polymer containing a protective group. In the present invention, a low molecular compound refers to a compound having a weight average molecular weight (weight average molecular weight) of less than 1,000, and a polymer refers to a polymer having a weight average molecular weight of 1,000 or more.

The compound having a polymerizable group polymerized by an acid refers to a compound in which, for example, when a composition is used as a resist composition, the polymerizable group is polymerized by the acid, and the solubility in the developing solution is changed. For example, in the case of water-based development, although it is soluble in the water-based developer, the acid generated by the photoacid generator through exposure causes the polymerizable group to polymerize in the exposed portion, and the Compounds with reduced solubility. In this case, an organic solvent developing solution may be used instead of the aqueous developing solution.

Examples of the polymerizable group polymerized by an acid include an epoxy group, a vinyloxy group, and an oxetanyl group. As the compound having the polymerizable group, a compound containing a styrene skeleton, a methacrylate or an acrylate skeleton having these polymerizable groups is preferably used.

The compound having a polymerizable group polymerized by an acid may be a polymerizable low-molecular compound or a polymer.

Examples of the cross-linking agent having a cross-linking effect due to an acid include a compound that changes solubility in a developing solution due to cross-linking of an acid when a composition is used as a resist composition, such as In the case of aqueous development, a compound that acts on a compound that is soluble in the aqueous developer and crosslinks the compound to reduce the solubility of the compound in the aqueous developer. in particular, Examples include methylated melamines such as 2,4,6-tri [bis (methoxymethyl) amino] -1,3,5-triazine, and 1,3,4,6-tetrakis (methoxymethyl) Methyl) urea and the like. In this case, examples of the compound to be crosslinked include compounds having a phenolic hydroxyl group and a carboxyl group.

The compound having a crosslinking effect due to an acid may be a polymerizable low-molecular compound or a polymer.

<6> Composition containing photosensitizer precursor

One aspect of the present invention is a resist composition containing the photosensitizer precursor, the photoacid generator, the hydroxyl-containing compound, and the acid-reactive compound.

With respect to the photosensitizer precursor in several aspects of the present invention, in the above composition, the photoacid generator generates an acid by irradiating active energy rays or the like, and the acid is deprotected to become a photosensitizer.

In the present invention, it is preferable that the photoacid generator generates an acid by the first irradiation using the first active energy ray, and the photosensitizer precursor becomes a photosensitizer because the acid is deprotected, and the photosensitizer is used by using the photoacid generator. The second active energy ray of the wavelength of the light absorbed by the agent is subjected to the second irradiation, and only the portion subjected to the first irradiation is caused by the action of the photosensitizer, and the photoacid generator can generate acid again. Thus, the acid further generates a photosensitizer, and at the same time, an acid-reactive compound that reacts with the acid can react.

As a resist composition which is one embodiment of the present invention, the following compositions can be more specifically exemplified.

A resist composition containing the photosensitizer precursor, the compound having a protective group deprotected by an acid, and a photoacid generator; the photosensitizer precursor containing the polyacrylamide due to an acid; A compound of a polymerizable group and a resist composition of the photoacid generator; a photosensitizer precursor, a crosslinker having a crosslinking action due to an acid, and a reaction with the crosslinker for development A compound whose solubility in a liquid is changed, a resist composition of a photoacid generator, and the like.

The photosensitizer precursor in one embodiment of the present invention can be preferably used as a sensitizer of a positive-type and a negative-type resist composition.

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 more preferably 0.5 to 2.0 molar equivalents with respect to the photoacid generator. When at least one of the photosensitizer precursor and the photoacid generator is a polymer, the mass of the portion from which the polymer main chain is removed is used as a reference.

The content of the photoacid generator in the resist composition according to one aspect of the present invention is preferably 1 to 50 parts by mass, and more preferably 1 to 100 parts by mass of the resist composition component from which the photoacid generator is removed. -30 mass parts, more preferably 1-15 mass parts. By including 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 improved. In the calculation of the content of the photoacid generator described above, the solvent is not included in 100 parts by mass of the resist composition component.

In the present invention, it is also preferred that each unit bonded to the same polymer is at least two selected from the group consisting of the photosensitizer precursor, the photoacid generator, the hydroxyl-containing compound, and the acid-reactive compound. And contain. This makes it possible to make the distribution in the resist composition uniform.

The photosensitizer precursor and at least one selected from the group consisting of the photoacid generator, the hydroxyl-containing compound, and the acid-reactive compound are simultaneously used as units of the same polymer. When contained, the unit functioning as the photosensitizer precursor is preferably 1 to 40 mol%, more preferably 10 to 35 mol%, and even more preferably 10 to 30 mol% in all units of the polymer.

When the photoacid generator and at least one member selected from the group consisting of the photosensitizer precursor, the hydroxyl-containing compound, and the acid-reactive compound are simultaneously contained as a unit of the same polymer, the photoacid generator is generated as the photoacid. The unit in which the agent functions 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 hydroxyl-containing compound and at least one selected from the group consisting of the photosensitizer precursor, the photoacid generator, and the acid-reactive compound are simultaneously contained as a unit of the same polymer, as the hydroxyl-containing compound In the case of a positive resist composition used for water-based development, the unit that functions is preferably 3 to 90 mol%, more preferably 5 to 80 mol%, and still more preferably 7 to mol% in all units of the polymer. 70 mol%. In the case of a negative-type resist composition used 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 and at least one selected from the group consisting of the photosensitizer precursor, the photoacid generator, and the hydroxyl-containing compound are simultaneously contained as a unit of the same polymer, before the photosensitizer The unit that functions as a bulk is preferably 3 to 40 mol%, more preferably 5 to 35 mol%, and even more preferably 7 to 30 mol% in all units of the polymer.

The weight average molecular weight of the polymer in one embodiment of the present invention is preferably 1,000 to 200,000, more preferably 2,000 to 50,000, and even more preferably 2,000 to 15,000. From the viewpoint of sensitivity, the preferred dispersion (molecular weight distribution) (Mw / Mn) of the polymer is 1.0 to 1.7, and more preferably It is 1.0 ~ 1.2. The weight average molecular weight and the degree of dispersion of the polymer are defined in terms of polystyrene conversion values measured by GPC.

In addition to the above-mentioned components, the composition according to an aspect of the present invention may further contain, as required, any combination of the following: an acid diffusion inhibitor and a surfactant used in a general resist composition , Organic carboxylic acids, solvents, dissolution inhibitors, stabilizers and pigments, sensitizers other than the aforementioned photosensitizer precursors, and the like.

The above-mentioned acid diffusion inhibitor can suppress the diffusion phenomenon of the acid generated by the photoacid generator in the resist film, and has the effect of suppressing an adverse chemical reaction in a non-exposed area. Therefore, the storage stability of the obtained resist composition improves, and the resolution as a resist improves. At the same time, it is possible to suppress a change in the line width of the resist pattern due to a change in the standing time from exposure to development processing, and obtain a resist composition having excellent process stability.

Examples of the acid diffusion inhibitor include compounds having one, two, or three nitrogen atoms in the same molecule, a sulfonylamine-containing compound, a urea compound, and a nitrogen-containing heterocyclic compound. In addition, as the acid diffusion inhibitor, a photodegradable peptone that generates a weak acid upon exposure to light can also be used. Examples of the photodegradable europium include an onium salt compound and an iodonium salt compound that have lost their ability to inhibit acid diffusion due to exposure to decomposition.

Specific examples include 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. 2010-243773, and Japanese Patent Laid-Open No. 2011-37835. And the compounds described in Japanese Patent Application Laid-Open No. 2012-173505.

The content of the acid diffusion inhibitor is preferably 0.01 to 100 parts by mass of the resist composition component. -10 parts by mass, more preferably 0.03 to 5 parts by mass, and still more preferably 0.05 to 3 parts by mass.

The surfactant is preferably used to improve coating properties. Examples of the surfactant include polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene polyoxypropylene block copolymers, sorbitol fatty acid esters, and polyoxyethylene. Non-ionic surfactants such as ethylene sorbitol fatty acid esters, fluorine-based surfactants, and organosiloxane polymers.

The content of the surfactant is preferably 0.0001 to 2 parts by mass, and 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 an aliphatic carboxylic acid, an alicyclic carboxylic acid, an unsaturated aliphatic carboxylic acid, a hydroxycarboxylic acid, an alkoxycarboxylic acid, a ketocarboxylic acid, a benzoic acid derivative, and orthophthalic acid. Formic 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 are preferred from the viewpoint of suppressing volatilization from the surface of the resist film and contaminating the drawing room when electron beam exposure is performed under vacuum. Among them, benzoic acid, 1-hydroxy-2-naphthoic acid, and 2 are preferred. -Hydroxy-3-naphthoic acid as an organic carboxylic acid.

The content of the organic carboxylic acid is preferably 0.01 to 10 parts by mass relative to 100 parts by mass of the resist composition component, more preferably 0.01 to 5 parts by mass, and still more preferably 0.01 to 3 parts by mass.

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, β-methoxyisobutyrate, ethyl butyrate, propyl butyrate, methyl Isobutyl ketone, ethyl acetate, acetic acid Isoamyl ester, ethyl lactate, toluene, xylene, cyclohexyl acetate, diacetone alcohol, N-methylpyrrolidone, N, N-dimethylformamidine, γ-butyrolactone, N, N-di Methylacetamide, propylene carbonate, ethylene carbonate, and the like. These solvents may be used alone or in combination.

The resist composition component is preferably dissolved in the solvent so that the solid content concentration becomes 1 to 40% by mass. It is more preferably 1 to 30% by mass, and even more preferably 3 to 20% by mass. By setting it as such a range of solid content concentration, the said film thickness can be implement | achieved.

The resist composition according to an aspect of the present invention may contain a fluorine-containing waterproof polymer in addition to the above. The fluorine-containing waterproof polymer is not particularly limited, and examples thereof include polymers generally used in immersion exposure processes, and the fluorine atom content rate is preferably higher than that of the polymers. Therefore, when the resist film is formed using the resist composition, the fluorine-containing waterproof polymer can be unevenly distributed on the surface of the resist film due to the waterproofness of the fluorine-containing waterproof polymer.

The composition of one aspect of the present invention can be obtained by mixing the components of the composition, and the mixing method is not particularly limited.

The resist composition according to an aspect 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 a substance produced by subjecting the sensitizer precursor to an acid treatment and hydrolysis. Each substituent in the following general formula (12) is the same as the substituent in the general formula (1). Therefore, it is not necessary to use an acid-based deprotection reaction, and it can be used as a photosensitizer having a molar absorption coefficient of 1.0 × 10 ⁵ cm ² / mol or more at absorption up to 365 nm. Therefore, it is also suitable as a chemically amplified resist composition for UV, and is particularly suitable for use in an optical device requiring high visible light transmittance. In the case of a chemically amplified resist for UV, even if the resist composition does not contain a hydroxyl-containing compound, the acid generation efficiency can be improved by containing the ketone derivative.

<7> Manufacturing method of device

One embodiment of the present invention is a method for manufacturing a device, which includes the steps of applying the composition to a substrate to form a resist film (hereinafter, also referred to as a "resist film forming step"); A step of irradiating a resist film with a first active energy ray (hereinafter, also referred to as a "first irradiation step"); a step of irradiating a resist film irradiated with the first active energy ray to a second active energy ray (hereinafter , Referred to as a "second irradiation step"); and a step of developing a pattern by developing the resist film irradiated with the second active energy ray (hereinafter, 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 using the first active energy ray, and the photosensitizer precursor becomes a photosensitizer due to the acid deprotection. Then, the second irradiation is preferably performed by using a second active energy ray having a wavelength at which the photosensitizer absorbs light. Due to the action of the photosensitizer, the photoacid generator can generate acid again only in the portion where the first irradiation is performed. . Thus, the acid further generates a photosensitizer, and at the same time, an acid-reactive compound that reacts with the acid can 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 by activating a photoacid generator contained in the composition, and examples thereof include KrF excimer laser and ArF excimer laser. , F ₂ excimer laser, electron beam, UV, visible light, X-ray, ion beam, g-ray, h-ray, i-ray, EUV, etc. Among them, electron beam, X-ray, EUV, and the like are preferred.

The second active energy ray used for the second irradiation may have a wavelength absorbed by a photosensitizer generated by deprotection of R ³ and R ⁴ of the photosensitizer precursor represented by the formula (1), and examples thereof include electromagnetic waves. Examples of the electromagnetic wave include KrF excimer laser, ArF excimer laser, F ₂ excimer laser, UV, visible light, g-ray, h-ray, and i-ray.

When the first active energy ray is an electromagnetic wave, the electromagnetic wave of the first active energy ray is preferably shorter than the wavelength of the electromagnetic wave used as the second active energy ray.

Except for using the composition containing the said photosensitizer precursor, what is necessary is just to use the manufacturing method of a normal apparatus.

One embodiment of the present invention may be a method for manufacturing a substrate, which uses the composition described above and includes a resist film forming step, a first irradiation step, a second irradiation step, and a pattern forming step. Pattern in front of the wafer.

In one aspect of the present invention, the film thickness of the resist film formed from the resist composition is preferably 10 to 200 nm. The above-mentioned resist composition is coated on the substrate by a suitable coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, and blade coating, and is prebaked at 60 to 150 ° C for 1 to 20 minutes, preferably 80 to 120. Pre-bake at ℃ for 1 ~ 10 minutes to form a thin film. The film thickness of this coating film is 10 ~ 200nm. Choose 20 ~ 150nm.

[Example]

Hereinafter, the present invention will be described in more detail through examples, but the present invention is not limited by these examples. In addition, in the following synthesis examples, the molar absorption coefficient of the compound after the acid treatment of the compound, that is, the molar absorption coefficient of the benzophenone compound derivative obtained at the deprotection of the compound at 365 nm, were measured using a UV-VIS absorbance photometer ( U-3300 (manufactured by Hitachi, Ltd.) was obtained 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 39 ml of a 1 mol / L methylmagnesium bromide solution was added dropwise thereto at 5 ° C or lower. After the dropwise addition, the mixture was stirred at 5 ° C or lower for 30 minutes to obtain a THF solution of 4-methylthiophenylmagnesium bromide. 8.8 g of 2,4-dimethoxybenzidine chloride was dissolved in 15 g of THF, and a solution of 4-methylthiophenylmagnesium bromide in THF was added dropwise to the obtained solution at 10 ° C or lower, and thereafter at 25 ° C Stir for 1 hour. After stirring, 50 g of a 10% by mass ammonium chloride aqueous solution was added at 20 ° C. or lower, and the mixture was stirred for 10 minutes, and the organic layer was extracted with 80 g of ethyl acetate. After washing with pure water, ethyl acetate and tetrahydrofuran were distilled off to obtain crude crystals. The crude crystals were recrystallized using 120 g of ethanol to obtain 7.6 g of 2,4-dimethoxy-4'-methylthiobenzophenone. The molar absorption coefficient at 365 nm in the chloroform solvent was 1.1 × 10 ⁶ cm ² / mol.

[Chemical 16]

(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, 47 mg of sulfuric acid, and 13.5 g of trimethyl orthoformate were dissolved in 12.5 g of methanol and stirred at reflux temperature for 3 hours. After cooling to room temperature, 50 g of a 5% by mass sodium bicarbonate aqueous solution was added thereto, followed by stirring for 10 minutes, and the precipitated crystals were filtered. The crystals were recovered, dissolved in 50 g of ethyl acetate, and washed with pure water. Thereafter, ethyl acetate was distilled off to obtain 4.0 g of (2,4-dimethoxy) phenyl- (4'-methylthio) phenyl-dimethoxymethane. The sum of the Hammett's substituent constants σ is -0.56.

(Synthesis Example 3) Synthesis of 4-fluoro-4'-methylthiobenzophenone

Except using 4-fluorobenzyl chloride instead of 2,4-dimethoxybenzyl chloride, the same operation as in Synthesis Example 1 was performed to obtain 4-fluoro-4'-methylsulfide. Substituted benzophenone 7.4g.

[Chemical 18]

(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, and 3.2 g of thiophenol and 4.0 g of potassium carbonate were added thereto and stirred at 70 ° C for 4 hours. After stirring, 90 g of pure water was added and stirred for 10 minutes, and the organic layer was extracted with 60 g of toluene. After washing three times with pure water, toluene was distilled off to obtain crude crystals. The crude crystals were recrystallized using 40 g of ethanol to obtain 5.6 g of 4-methylthio-4'-phenylthiobenzophenone. The molar absorption coefficient at 365 nm in the chloroform solvent was 2.6 × 10 ⁶ cm ² / mol.

(Synthesis Example 5) Synthesis of (4-methylthio) phenyl- (4'-phenylthio) phenyl-dimethoxymethane (precursor compound B2)

Use 4-methylthio-4'-phenylthiobenzophenone instead of 2,4-dimethoxy-4'-methylthiobenzophenone. The same operation as in Synthesis Example 2 above yields To 3.1 g of (4-methylthio) phenyl- (4'-phenylthio) phenyl-dimethoxymethane. Hammett's substituent constant is 0.2 or less.

(Synthesis Example 6) Synthesis of (4-methylthio) phenyl- (4'-phenylthio) phenyl-diethoxymethane (precursor compound B3)

5.0 g of (4-methylthio) phenyl- (4'-phenylthio) phenyl-dimethoxymethane obtained in Synthesis Example 5, 300 mg of camphorsulfonic acid, and triethyl orthoformate 4.3 g was dissolved in 32.5 g of dehydrated ethanol, and the temperature of the solution was 70 ° C. The methanol and ethanol in the solution were distilled off together and stirred for 5 hours. After cooling to room temperature, 50 g of a 5% by mass sodium bicarbonate aqueous solution was 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 purified by column chromatography (ethyl acetate / cyclohexane = 5/95 (volume ratio)) to obtain (4-methylthio) phenyl- (4'-benzene Thio) phenyl-diethoxymethane 4.6 g. The sum of the Hammett's substituent constants σ is 0.2 or less.

[Chemical 21]

(Synthesis Example 7) Synthesis of 2- (4-methylthio) phenyl-2- (4'-phenylthio) phenyl-1,3-dioxolane (precursor compound B4)

Instead of using dehydrated ethylene glycol instead of dehydrated ethanol, the same operation as in Synthesis Example 6 was performed to obtain 2- (4-methylthio) phenyl-2- (4'-phenylthio). ) Phenyl-1,3-dioxolane 4.6 g. The sum of the Hammett's substituent constants σ is 0.2 or less.

(Synthesis Example 8) Synthesis of 2-methoxy-4'-methylthiobenzophenone (sensitizer compound A3)

Except using 2-methoxybenzyl chloride instead of 2,4-dimethoxybenzyl chloride, the same operation as in Synthesis Example 1 was performed to obtain 2-methoxy-4 ' -Methylthiobenzophenone. The molar absorption coefficient at 365 nm in the 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)

Use 2-methoxy-4'-methylthiobenzophenone instead of 2,4-dimethoxy-4'-methylthiobenzophenone. In the same manner as in Synthesis Example 2, 2.7 g of 2- (2-methoxyphenyl) -2- (4'-methylthiophenyl) -dimethoxymethane was obtained. The sum of the Hammett's substituent constants σ is -0.37.

(Synthesis Example 10) Synthesis of 4- (4-methoxyphenyl) -4'-methylthiobenzophenone (sensitizer compound A4)

Instead of using 2,4-dimethoxybenzyl chloride instead of 4- (4-methoxyphenyl) benzyl chloride, 4 was obtained by performing the same operation as in Synthesis Example 1 above. -(4-methoxyphenyl) -4'-methylthiobenzophenone 5.2 g. The molar absorption coefficient at 365 nm in the 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)

Use 4- (4-methoxyphenyl) -4'-methylthiobenzophenone instead of 2,4-dimethoxy-4'-methylthiobenzophenone By performing the same operation as in Synthesis Example 2 above, 4.1 g of (4-methoxyphenyl) -phenyl- (4'-methylthiophenyl) -dimethoxymethane was obtained. The sum of the Hammett's substituent constants 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 were dissolved in 15 g of dichloromethane. 5.0 g of 4-methoxybenzidine chloride was added dropwise thereto at 30 ° C or lower over 30 minutes. Thereafter, after stirring at 5 ° C for 2 hours, 15 g of pure water was added to 25 ° C or lower, and the mixture was stirred for 10 minutes. The organic layer was separated and recovered, washed with pure water, and dichloromethane was distilled off. The obtained residue was recrystallized using 70 g of ethanol to obtain 2-methylthio-4,4'-dimethoxydibenzoyl. Ketone 6.5g. The molar absorption coefficient at 365 nm in the 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-4,4'-dimethoxybenzophenone is used instead of 2,4-dimethoxy-4'-methylthiobenzophenone, in addition, by The same operation as in Synthesis Example 2 was performed to obtain 3.7 g of (2-methylthio-4-methoxy) phenyl- (4'-methoxy) phenyldimethoxymethane. The sum of the Hammett's substituent constants σ is -0.33.

(Synthesis Example 14) Synthesis of 4- (2-vinyloxy) ethylthiostilbene

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 and stirred at the reflux temperature for 3 hours. Then, it cooled to room temperature, 60 g of pure water was added, and it stirred for 5 minutes. 90 g of toluene was added thereto for extraction, and the solution was separated and washed with pure water. Thereafter, toluene was 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) ethylthiobromobenzene was used in place of 4-bromothioanisole, and the same operation as in Synthesis Example 1 was performed to obtain 4- (2- Vinyloxy) ethylthio-2 ', 4'-dimethoxybenzophenone) 8.4 g. The molar absorption coefficient at 365 nm in the 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, 3.3 g of pure water, and 0.44 g of pyridinium p-toluenesulfonate were added to 30 g of acetone. The mixture was stirred at the reflux temperature for 3 hours. Then, it cooled to room temperature, 85g of pure water was added, and after stirring for 5 minutes, it extracted with ethyl acetate. After separating and washing with pure water, ethyl acetate was distilled off to obtain 4.6 g of 4- (2-hydroxy) ethylthio-2 ', 4'-dimethoxybenzophenone.

(Synthesis Example 17) Synthesis of 4- (2-methylpropenyloxy) ethylthio-2 ', 4'-dimethoxybenzophenone (sensitizer compound A6)

5 g of 4- (2-hydroxy) ethylthio-2 ', 4'-dimethoxybenzophenone and 2.9 g of methacrylic anhydride were dissolved in 15 g of THF, and the temperature was changed to 20 ° C over 30 minutes. Among them, 1.9 g of triethylamine was added dropwise. After the dropwise addition, after stirring at 25 ° C for 3 hours, 40 g of pure water was added and the mixture was stirred for 10 minutes. It was extracted with 50 g of ethyl acetate and separated and washed with pure water. Thereafter, ethyl acetate was distilled off to obtain 5.1 g of the target product 4- (2-methacrylfluorenyloxy) ethylthio-2 ', 4'-dimethoxybenzophenone. The molar absorption coefficient at 365 nm in the chloroform solvent was 1.1 × 10 ⁶ cm ² / mol.

(Synthesis Example 18) 4-[(2-Methacryloxy) ethylthio] -phenyl- (2 ', 4'-dimethoxyphenyl) dimethoxymethane (precursor compound B8) Synthesis

Use 4- (2-methylpropenyloxy) ethylthio-2 ', 4'-dimethoxybenzophenone instead of 2,4-dimethoxy-4'-methylthiodione Except for benzophenone, the same operation as in Synthesis Example 2 described above was performed to obtain 4-[(2-methylpropenyloxy) ethylthio] -phenyl- (2 ', 4' -2.6 g of dimethoxyphenyl) dimethoxymethane. The sum of the Hammett's substituent constants σ is -0.56.

(Synthesis Example 19) Synthesis of 4- (4-hydroxyphenylthio) -4'-methylthiobenzophenone (sensitizer compound A7)

Except using 4-hydroxybenzenethiol instead of thiophenol, the same operation as in Synthesis Example 4 was performed to obtain 4- (4-hydroxyphenylthio) -4'-methylthiodiol. Benzophenone 5.8g. The molar absorption coefficient at 365 nm in the chloroform solvent was 3.01 × 10 ⁶ cm ² / mol. The molar absorption coefficient at 365 nm in the acetonitrile solvent was 1.73 × 10 ⁶ cm ² / mol.

(Synthesis Example 20) Synthesis of 4- (4-hydroxyphenylthio) phenyl-4'-methylthiophenyl-dimethoxymethane (precursor compound B9)

Use 4- (4-hydroxyphenylthio) -4'-methylthiobenzophenone instead of 2,4-dimethoxy-4'-methylthiobenzophenone, By carrying out the same operation as in Synthesis Example 2 above, 3.3 g of 4- (4-hydroxyphenylthio) phenyl-4'-methylthiophenyl-dimethoxymethane was obtained. The sum of the Hammett's substituent constants σ is 0.2 or less.

(Synthesis Example 21) Synthesis of 4,4'-bis (4-hydroxyphenylthio) benzophenone (sensitizer compound A8)

6.5 g of 4,4′-difluorobenzophenone was dissolved in 20 g of DMF, 11.3 g of 4-hydroxybenzenethiol and 12.4 g of potassium carbonate were added thereto, and the mixture was stirred at 70 ° C. for 2 hours. After stirring, 90 g of pure water was added and stirred for 10 minutes to precipitate a solid. The precipitated solid was recovered by filtration and vacuum dried to obtain crude crystals. The crude crystals were dispersed in 120 g of dichloromethane and stirred for 1 hour. After stirring, the solid was recovered by filtration and dried under vacuum to obtain 12.0 g of 4,4'-bis (4-hydroxyphenylthio) benzophenone. The molar absorption coefficient at 365 nm in the acetonitrile solvent was 2.77 × 10 ⁶ cm ² / mol.

(Synthesis Example 21) Synthesis of bis [4- (4-hydroxyphenylthio) phenyl] -dimethoxymethane (precursor compound B10)

Using 4,4'-bis (4-hydroxyphenylthio) benzophenone instead of 2,4-dimethoxy-4'-methylthiobenzophenone, in addition, The same operation as in Synthesis Example 2 above was performed to obtain 3.0 g of bis [4- (4-hydroxyphenylthio) phenyl] -dimethoxymethane. The sum of the Hammett's substituent constants σ is 0.2 or less.

(Synthesis Example 22) Synthesis of 4- [4- (methoxymethoxy) phenylthio] phenyl-4'-methylthiophenyl-dimethoxymethane (precursor compound B11)

2.0 g of 4- (4-hydroxyphenylthio) phenyl-4'-methylthiophenyl-dimethoxymethane obtained in Synthesis Example 20 was dissolved in 8.0 g of DMF, and chloromethyl was added thereto. 0.61 g of methyl ether and 1.1 g of potassium carbonate were stirred at 70 ° C. for 12 hours. After stirring, 16 g of pure water and 32 g of dichloromethane were added to recover the organic layer, and the organic layer was 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 obtain 4- [4- (methoxymethoxy) phenylthio). ] 1.2 g of phenyl-4'-methylthiophenyl-dimethoxymethane. The sum of the Hammett's substituent constants σ is 0.2 or less.

(Synthesis Example 23) Synthesis of 4- [4- (tert-butoxycarbonyloxy) phenylthio] phenyl-4'-methylthiophenyl-dimethoxymethane (precursor compound B12)

2.0 g of 4- (4-hydroxyphenylthio) phenyl-4'-methylthiophenyl-dimethoxymethane obtained in Synthesis Example 20 was dissolved in 12.0 g of methylene chloride, and added thereto 1.6 g of di-tert-butyl dicarbonate, 0.76 g of triethylamine, and 92 mg of N, N-dimethyl-4-aminopyridine were stirred at room temperature for 6 hours. After stirring, 12 g of pure water was added to recover the organic layer, and the organic layer was washed twice with pure water. Thereafter, the organic solvent was distilled off and purified by column chromatography (ethyl acetate / hexane = 1/3 (volume ratio)) to obtain 4- [4- (tert-butoxycarbonyloxy) phenylsulfide. Alkyl] phenyl-4'-methylthiophenyl-dimethoxymethane 1.3 g. The sum of the Hammett's 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 a 35% aqueous hydrochloric acid solution were dissolved in 28 g of dehydrated dioxane. 2.73 g of cyclohexyl vinyl ether was dissolved in 2.80 g of dehydrated dioxane, and the solution was added dropwise to the polyhydroxystyrene solution over 30 minutes. After the dropwise addition, the mixture was stirred at 40 ° C for 2 hours. After stirring, 0.014 g of dimethylaminopyridine was added after cooling. Thereafter, the solution was dropped into 260 g of pure water to precipitate a copolymer. This was separated by filtration under reduced pressure, and the separated solid was washed twice with 300 g of pure water, and then dried under vacuum to obtain the following copolymer as a white solid. A 9.2g. In addition, the monomer ratio of the copolymer unit in this invention is not limited to the following.

(Synthesis example 25) Synthesis of copolymer B

7.0 g of ethoxylated styrene, 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) was dissolved in 35 g of tetrahydrofuran (THF) for deoxygenation. This was added dropwise over 4 hours to 20 g of THF which had been fluidized with nitrogen to a reflux temperature in advance. After the dropwise addition, the mixture was stirred for 2 hours and then cooled to room temperature. This was dropped into a mixed solvent of 149 g of hexane and 12 g of THF to precipitate a copolymer. The solid obtained by filtration under reduced pressure was washed with 52 g of hexane, and then dried under vacuum to obtain 10.3 g of a copolymer B represented by the following formula. The weight average molecular weight calculated by polystyrene conversion using gel permeation chromatography was 9,200. In addition, the monomer ratio of the copolymer unit in this invention is not limited to the following.

[Chemical 41]

(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 stirred at the reflux temperature for 6 hours. Then, it cooled to 25 degreeC, the obtained solution was dripped at the mixed liquid of 30 g of acetone, and 30 g of pure water, and the copolymer was precipitated. After filtering under reduced pressure for separation, the separated solid was washed twice with 30 g of pure water and then dried under vacuum to obtain 4.3 g of a copolymer C represented by the following formula as a white solid. The weight average molecular weight calculated by polystyrene conversion by gel permeation chromatography was 9,100. In addition, the monomer ratio of the copolymer unit in this invention is not limited to the following.

(Synthesis example 27) Synthesis of copolymer D

5.0 g of α-methacryloxy-γ-butyrolactone and 2-methyladamantane-2-methylpropane 6.0 g of enoate, 3.6 g of 2-hydroxynorbornene-1-methacrylate, and 0.51 g of V601 were dissolved in 26 g of tetrahydrofuran and degassed under reduced pressure. This was added dropwise to a flask in which 4 g of THF was refluxed over 4 hours. After stirring for 2 hours, the solution was cooled to 25 ° C. This solution was dropped into a mixed solvent consisting of 160 g of hexane and 18 g of tetrahydrofuran, and the solution was reprecipitated. After filtration, the dispersion was washed twice with 37 g of hexane, and filtered and dried under vacuum to obtain 7.7 g of a copolymer D of a target product as a white powder. The weight average molecular weight calculated by polystyrene conversion using gel permeation chromatography was 9,700.

(Synthesis example 28) Synthesis of copolymer E

0.80 g of the aforementioned precursor compound B8, 3.9 g of α-methacryloxy-γ-butyrolactone, 2.9 g of 2-methyladamantane-2-methacrylate, and (4-hydroxy) phenylmethyl 2.3 g of methacrylate, 0.13 g of butyl mercaptan, and 0.58 g of V601 were dissolved in 12.5 g of tetrahydrofuran and degassed under reduced pressure. After deaeration, it was added dropwise to a flask in which 4 g of THF was refluxed by fluidization with nitrogen over 4 hours. After stirring for 2 hours, the solution was cooled to 25 ° C. After cooling, it was added dropwise to a mixed solvent composed of 107 g of hexane and 11 g of tetrahydrofuran to reprecipitate.

After filtering, the dispersion was washed twice with 37 g of hexane, and after filtration, vacuum drying was performed to obtain a white color. 6.2 g of copolymer E of powdery target product. The weight average molecular weight calculated by polystyrene conversion using gel permeation chromatography was 8,600.

(Synthesis example 29) Synthesis of copolymer F

Weigh 0.80 g of the aforementioned precursor compound B8, 3.9 g of α-methacryloxy-γ-butyrolactone, 2.9 g of 2-methyladamantane-2-methacrylate, and (4-hydroxy) benzene 2.3 g of methyl methacrylate, 0.49 g of 5-phenyldibenzothienium 1,1-difluoro-2- (2-methylpropenyloxy) -ethanesulfonate, 0.13 g of butyl mercaptan 2.9 g of (4-hydroxy) phenyl methacrylate, dimethyl-2,2'-azobis (2-methylpropionate) (product name V601, manufactured by Wako Pure Chemical Industries, Ltd., ( Hereinafter referred to as "V601") 0.56 g, dissolved in 12.2 g of tetrahydrofuran, and degassed under reduced pressure. After degassing, it was added dropwise over 4 hours to a flask where 4 g of THF was refluxed by fluidization with nitrogen. After stirring for 2 hours, it was cooled to 25 ° C. After cooling, it was added dropwise to a mixed solvent consisting of 107 g of hexane and 11 g of tetrahydrofuran to reprecipitate. After filtering, it was dispersed and washed twice with 37 g of hexane. After filtration, it was vacuum dried. 6.6 g of the target product copolymer F was obtained as a white powder. The weight-average molecular weight calculated by polystyrene conversion using gel permeation chromatography was 9,100.

(Synthesis example 30) Synthesis of copolymer G

5.0 g of α-methacryloxy-γ-butyrolactone, 6.0 g of 2-methyladamantane-2-methacrylate, and 0.51 g of V601 were dissolved in 26 g of tetrahydrofuran and degassed under reduced pressure. This was added dropwise to a flask in which 4 g of THF was refluxed over 4 hours. After stirring for 2 hours after the dropwise addition, the mixture was cooled to 25 ° C. This solution was dropped into a mixed solvent consisting of 160 g of hexane and 18 g of tetrahydrofuran, and the solution was reprecipitated. This was filtered and dispersed and washed twice with 37 g of hexane. After filtration, vacuum drying was performed to obtain 7.4 g of a copolymer G of a target product as a white powder.

(Comparative Synthesis Example 1) Synthesis of Copolymer H

5.0 g of α-methacryloxy-γ-butyrolactone, 6.0 g of 2-methyladamantane-2-methacrylate, 4.0 g of adamantane-1-methacrylate, and 0.51 g of V601 It was dissolved in 26 g of tetrahydrofuran and degassed under reduced pressure. This was added dropwise to a flask in which 4 g of THF was refluxed over 4 hours. After stirring for 2 hours, the solution was cooled to 25 ° C. This solution was dropped into a mixed solvent consisting of 160 g of hexane and 18 g of tetrahydrofuran, and the solution was reprecipitated. After filtering, the dispersion was washed twice with 37 g of hexane, and after filtration, vacuum drying was performed to obtain 8.0 g of a copolymer H of a target product as a white powder. The weight average molecular weight calculated by polystyrene conversion using gel permeation chromatography was 8,800.

<Preparation of sample for sensitivity evaluation ("evaluation sample") 1>

Evaluation samples 1 to 20 were prepared as described below. In 7000 mg of cyclohexanone, the following substances were added in the following proportions to prepare a sample: selected from the group consisting of the above-mentioned copolymers A, C, and G 500 mg, copolymer E 507 mg, copolymer F 497 mg, and copolymer H 500 mg Resin of any one; diphenyliodonium-nonafluorobutanesulfonate (DPI-Nf) or phenyldithiophenium-nonafluorobutanesulfonate (PBpS- Nf) 0.043 mmol; precursor compounds B1 to 3, B9, and B10 as photosensitizer precursors; 2,2-diphenyl-1,3-dioxolane (compound C1) as a comparative compound (Ha The sum of the Mitte substituent constants σ is 0, and the molar absorption coefficient at 365 nm in a chloroform solvent is 6.3 × 10 ⁴ cm ² / mol). Any of 0.043 mmol or no added; trioctylamine as a quencher 0.0043 mmol; 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. The details of the prepared sample are shown in Table 1.

<Sample Evaluation 1>

Each of the evaluation samples 1 to 20 was coated on a Si wafer previously treated with hexamethyldisilazane (HMDS), spin-coated, and heated at 110 ° C. to obtain a resist film having a thickness of 100 nm.

Next, a 30 keV EB drawing device was used to change the exposure amount to form a 1: 1 line and space pattern with a half-pitch of 100 nm at a line width of 100 nm, and the evaluation sample resist film was exposed. Thereafter, the entire surface of the wafer was irradiated with ultraviolet rays using a UV lamp having a bright line of 365 nm. Next, it was heated on a hot plate at 110 ° C for 1 minute. After heating, develop using a developer (product name: NMD-3, tetramethylammonium hydroxide 2.38% by mass, manufactured by Tokyo Chemical Industry Co., Ltd.) for 1 minute, and rinse with pure water. Wash to get the pattern. The observation was performed with a microscope, and the exposure amount at which the resist was completely peeled off was taken as the E size (minimum exposure amount). The results of evaluating the minimum exposure amount as the sensitivity are shown in Table 2.

As shown in Table 2, in Examples 1 to 9 and 13 to 16 in which the resist composition containing the photosensitizer precursor in one embodiment of the present invention was used, the minimum exposure amount of EB was changed by irradiating UV after EB irradiation. small. Thus, in the resist compositions of Examples 1 to 9 and 13 to 16, the photosensitization of the photosensitizer generated from the photosensitizer precursor leads to an increase in acid generation efficiency and sensitivity. In addition, it can be seen from the comparison between Example 4 and Comparative Example 1 and Example 7 and Comparative Example 2 that by including a compound having a hydroxyl group in a resist, the EB-based The acid production efficiency is improved, and high sensitivity is achieved.

It can be seen from the comparison between Examples 1 to 4 and Comparative Example 1 that even if the same precursor compound B1 is used as the photosensitizer precursor, the copolymers A and C having a large proportion of hydroxyl groups, especially hydroxyaryl groups in the composition are used. High photosensitization efficiency. The reason for this is considered to be that the hydroxyaryl group functions as an excellent proton donor in the hydroxy group. In addition, by making the copolymer have a large number of hydroxy groups, the polarity of the resist becomes high, and a photosensitizer precursor is generated. As the photosensitizer becomes stable, the absorption tends to be longer, and the molar absorption coefficient at 365nm increases. In addition, it can be seen from the comparison of Examples 4 and 5 that for the effect of UV irradiation, as long as the sum of the Hammett substituent constants σ is 0.2 or less, the larger the molar absorption coefficient of the photosensitizer generated from the photosensitizer precursor, the more For high sensitivity.

In addition, as shown in Examples 10 and 11, when the precursor compound B8 was bonded to the polymer, the acid generation efficiency by UV irradiation was higher than that of Examples 1 to 9. This is because the generated photosensitizer is uniformly dispersed in the resist, and the probability of reaction between the photosensitizer and the photoacid generator is higher than that in the case where the photosensitizer precursor is mixed in the resist. As shown in Example 12, when the precursor compound B8 and PAG were bonded to the polymer, the acid generation efficiency based on UV irradiation was higher than that of Examples 10 and 11.

As can be seen from Comparative Examples 5, 13, and 14, when the precursor compound B9 or B10 is mixed with the resist, the sensitivity is higher than when the precursor compound B2 is mixed with the resist. This is because, like the sensitizer compounds A7 and A8 produced from the precursor compounds B9 and B10, the introduction of 4-hydroxyphenylthio group increases the molar absorption coefficient at 365 nm, and the phenolic hydroxyl group improves electron-donating properties. In addition, the phenolic hydroxyl group of the photosensitizer becomes a proton source, and the photosensitized acid production efficiency caused between the photosensitizer and the acid generator is improved.

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

<Preparation of sample for sensitivity evaluation ("evaluation sample") 2>

Evaluation samples 16 to 25 were prepared as described below. The following substances were added to 7000 mg of cyclohexanone in the following proportions to prepare a sample: the above-mentioned copolymer A or H 500 mg; as a photoacid generator (PAG) Diphenyliodonium-nonafluorobutane sulfonate (DPI-Nf), phenyldibenzothiophenium-nonafluorobutane sulfonate (PBpS-Nf) or (4-phenylthio) benzene Diphenylphosphonium-nonafluorobutane sulfonate (PSDPS-Nf) 0.043 mmol; 0.043 mmol of any of the sensitizer compounds A1, A2, A7, and A8 as a photosensitizer or not added; as quenching Trioctylamine was 0.0043 mmol. The details of the prepared sample are shown in Table 3.

<Sample Evaluation 2>

Each of the evaluation samples 21 to 32 was coated on a Si wafer subjected to hexamethyldisilazane (HMDS) treatment in advance, spin-coated, and heated at 110 ° C. to obtain a resist film having a thickness of 500 nm.

Next, the exposure amount was changed using a UV exposure apparatus having a bright line of 365 nm across a 1: 1 line and a space pattern mask with a half pitch of 2 μm of line width, and the evaluation sample resist film was exposed . Next, it was heated on a hot plate at 110 ° C for 1 minute.

After heating, development was performed using a developing solution (product name: NMD-3, tetramethylammonium hydroxide 2.38% by mass, manufactured by Tokyo Yingka Kogyo Co., Ltd.) for 1 minute, and the pattern was washed with pure water. The observation was performed with a microscope, and the exposure amount at which the resist was completely peeled off was taken as the E size (minimum exposure amount). The results of evaluating the minimum exposure amount as sensitivity are shown in Table 4.

As shown in Comparative Example 5, PBpS-Nf has no UV absorption at 365 nm, and therefore does not generate acid. However, Examples 17, 18, and 19 used a resist composition containing a photosensitizer in one embodiment of the present invention. 21, 24, and 25, because the added photosensitizer absorbs light during UV irradiation and sensitizes the acid generator to generate acid. In addition, the sensitivity of any of the examples was higher than that of Comparative Examples 6 and 7 in which an acid generator having UV absorption at 365 nm was mixed. As a result, in the resist compositions of Examples 17 to 25, acid generation increased and sensitivity increased. The results of Example 20 and Comparative Example 6, and Example 23 and Comparative Example 7 show that even for irradiation The wavelength UV has an acid generator that absorbs, and the effect of the photosensitizer tends to be highly sensitive.

By comparing Examples 17, 18, 24, and 25, it can be seen that the larger the molar absorption coefficient of the added sensitizer compound, the higher the sensitivity. In addition, like the sensitizer compounds A7 and A8, by introducing a hydroxyl group into the thioaryl structure, the electron-donating property is improved, so that the sensitivity of Examples 24 and 25 is higher. In addition, since the phenolic hydroxyl group of the sensitizer compound becomes a proton source, the acid production efficiency of the sensitization reaction caused between the photosensitizer and the acid generator is improved.

[Industrial availability]

According to several aspects of the present invention, a resist composition containing a photosensitizer precursor can be provided. Photosensitizer precursors are used to improve the efficiency of acid production and form photoresists with high sensitivity, high resolution, and high LWR characteristics.

Claims (13)

A resist composition comprising a photosensitizer precursor represented by the following general formula (1), a photoacid generator, a hydroxyl-containing compound, and an acid-reactive compound, In the formula (1), Ar ¹ and Ar ² are each independently a phenylene group which may have a substituent, and R ¹ is selected from the group consisting of a thioalkoxy group, an arylthio group, and a thioalkyl group which may have a substituent. In any one of the groups consisting of oxyphenyl, X is any one selected from the group consisting of a sulfur atom, an oxygen atom, and a direct bond, and R ² is an alkyl group and a phenyl group which may have a substituent. In each of Y, Y is each independently an oxygen atom and a sulfur atom, and 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, and at least one carbon-carbon single bond in the alkyl group of R ¹ , R ² , R ^3, and R ⁴ may be A carbon-carbon double bond or a carbon-carbon triple bond is substituted, and at least one methylene group in the alkyl group possessed by R ¹ , R ² , R ^3, and R ⁴ may be substituted by a divalent hetero atom-containing group. The resist composition according to claim 1, wherein the hydroxyl-containing compound is a compound containing a hydroxyaryl group. The resist composition according to claim 1 or 2, wherein a molar absorption coefficient at 365 nm after the photosensitizer precursor is treated 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 the Ar ¹ and / or the 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 resist composition according to any one of claims 1 to 5, wherein the Ar ¹ and / or the Ar ² further has a member selected from the group consisting of an alkoxy group, a thioalkoxy group, an arylthio group, and At least one of the group consisting of a thioalkoxyphenyl group is used as a substituent, and the substituent is bonded to the ortho and / or para position of the Ar ¹ and / or the Ar ² . The resist composition according to any one of claims 1 to 6, wherein the R ^{1 is} bonded to an ortho or para position of the 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, the X is bonded to an ortho or para position of the Ar ² . The resist composition according to any one of claims 1 to 8, further comprising a member selected from the group consisting of the photosensitizer precursor, the photoacid generator, the hydroxyl-containing compound, and the acid-reactive compound. At least two of the groups constituted as each unit bonded to the same polymer. The resist composition according to any one of claims 1 to 9, further comprising at least any one selected from the group consisting of an acid diffusion inhibitor, a surfactant, a dissolution inhibitor, and a solvent. A method for manufacturing a device has the following steps: A step of applying the resist composition according to any one of claims 1 to 10 on a substrate to form a resist film; a step of irradiating the resist film with a first active energy ray; The step of irradiating the resist film after the first active energy ray with the second active energy ray; and the step of developing the resist film after irradiating the second active energy ray to obtain a pattern. The method for manufacturing a device according to claim 11, wherein the first active energy ray is a particle beam or an electromagnetic wave, and when the first active energy ray is a particle beam, the second active energy ray is an electromagnetic wave, so When the first active energy ray is an electromagnetic wave, the second active energy ray is an electromagnetic wave having a wavelength longer than the electromagnetic wavelength of the first active energy ray. The method for manufacturing a device according to claim 11 or 12, wherein the first active energy ray is an electron beam or extreme ultraviolet rays.