TW201420553A - Photoresist composition, method for forming resist pattern, and acid generator - Google Patents

Abstract

The present invention is a photoresist composition which contains: a polymer that has a structural unit containing an acid-cleavable group; and an acid generator that contains a compound represented by formula (1). In formula (1), R1 represents a substituted or unsubstituted monovalent hydrocarbon group having 1-30 carbon atoms or a substituted or unsubstituted monovalent heterocyclic group having 3-30 ring atoms; R2 represents an alkanediyl group having 1-30 carbon atoms or a fluorinated alkanediyl group having 2-30 carbon atoms, with the number of the fluorine atoms being smaller than the number of the carbon atoms; and Q+ represents a monovalent photodecomposable organic cation.

Description

Photoresist composition, resist pattern formation method and acid generator

The present invention relates to a photoresist composition, a resist pattern formation method, and an acid generator.

In the field of microfabrication represented by the manufacture of integrated circuit components, in the past, a resist film having a polymer having an acid dissociable group was used to form a resist film on a substrate, and the mask pattern was blocked. The film is exposed to exposure light of a short wavelength such as excimer laser light, and the exposed portion is removed by a developing solution to form a fine resist pattern. In this case, a chemically amplified resist which enhances sensitivity by the action of an acid is used in the photoresist composition containing an acid generator which generates an acid by exposure. However, at present, with the advancement of lithography such as high integration and high speed of integrated circuits, it is required to form a photoresist composition having a finer resist pattern. In addition, the photoresist composition is required to have excellent resolution, and it is required to have excellent cross-sectional shape of the pattern, and the MEEF (mask error enhancement coefficient (Mask) of the mask size dependence of the pattern width is displayed. Error Enhancement Factor)) Excellent performance.

For these requirements, various acid generators have been developed The photoresist composition (see JP-A-2007-145803 and International Publication No. 2011/104127). However, more and more towards the development of the refinement of the resist pattern today requires more excellent MEEF performance. Further, in the resist composition described above, the resist pattern formed tends to have a top loss or the like, and the rectangular shape of the cross-sectional shape is also insufficient. Moreover, as the resist film is thinned, the resist pattern is also required to have excellent etching resistance.

[Previous Technical Literature] [Patent Document]

[Patent Document 1] JP-A-2007-145803

[Patent Document 2] International Publication No. 2011/104127

The present invention has been made in view of the above circumstances, and an object thereof is to provide a resist composition which can form a resist pattern having excellent MEEF performance, a rectangular shape in cross-sectional shape, and excellent etching resistance.

The invention for solving the above problems is a photoresist composition containing a polymer having a structural unit containing an acid-dissociable group (hereinafter also referred to as "[A] polymer"), and a formula (1) An acid generator (hereinafter also referred to as "the compound (1)")) (hereinafter referred to as "[B] acid generator"), [Chem. 1] R ¹ -SO ₂ OR ² -SO ₃ ^- Q ⁺ (1)

(In the formula (1), R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 30 carbon atoms or a substituted or unsubstituted monovalent heterocyclic group having 3 to 30 ring atoms, and R ² is a carbon number 1~ 30 alkanediyl or a fluorinated alkanediyl group having a fluorine number of less than 2 to 30 carbon atoms, and Q ⁺ is a monovalent photodecomposable organic cation).

Another invention for solving the above problems is a resist pattern forming method having the steps of: forming a resist film, exposing the resist film, and developing the exposed resist film And a step of forming the above-mentioned resist film by the photoresist composition.

Another invention for solving the above problems is an acid generator containing a compound represented by the following formula (1): R ² -SO ₂ OR ² -SO ₃ ^- Q ⁺ (1)

(In the formula (1), R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 30 carbon atoms or a substituted or unsubstituted monovalent heterocyclic group having 3 to 30 ring atoms, and R ² is a carbon number 1~ 30 alkanediyl or a fluorinated alkanediyl group having a fluorine number of less than 2 to 30 carbon atoms, and Q ⁺ is a monovalent photodecomposable organic cation).

Here, the "hydrocarbon group" means a group consisting of a carbon atom and a hydrogen atom, and is classified into a "chain hydrocarbon group", an "alicyclic hydrocarbon group", and an "aromatic hydrocarbon group". The "chain hydrocarbon group" means a hydrocarbon group which does not contain a cyclic structure and has only a chain structure. The "alicyclic hydrocarbon group" means a hydrocarbon group having only an alicyclic structure as a ring structure. However, it is not necessarily composed only of an alicyclic structure, and a part thereof may have a chain structure. The "aromatic hydrocarbon group" means a hydrocarbon group having an aromatic ring structure as a ring structure. However, it is not necessarily composed only of an aromatic ring structure, and a part thereof may have an alicyclic structure or a chain structure. The chain hydrocarbon group and the chain structure may be linear or branched.

The "heterocyclic group" is a ring structure identical to an alicyclic hydrocarbon group or an aromatic hydrocarbon group, and contains an atom other than carbon as a ring constituting atom. The atom other than carbon is exemplified by one or more hetero atoms such as sulfur, nitrogen, and oxygen. The heterocyclic group may be a monocyclic ring or a polycyclic ring, and may be an aromatic heterocyclic group or an aliphatic heterocyclic group. However, it is not necessarily composed only of a heterocyclic structure, and a part thereof may contain an alicyclic structure, an aromatic ring structure, a chain structure, or the like. The chain structure may be linear or branched.

According to the photoresist composition and the resist pattern forming method of the present invention, it is possible to form a resist pattern having excellent cross-sectional shape rectangularness and etching resistance while exhibiting excellent MEEF performance. Further, the acid generator of the present invention can be preferably used as a component of the photoresist composition. Accordingly, these can be preferably used in the pattern formation of the lithography step of various electronic devices such as semiconductor devices and liquid crystal devices.

<Photoresist composition>

The photoresist composition contains the [A] polymer and the [B] acid generator. The resist composition may further contain a [C] acid diffusion controlling agent, [D] a fluorine atom-containing polymer, and [E] a solvent as suitable components, and may also contain a range which does not impair the effects of the present invention. [F] Other optional components such as a partialization accelerator. Hereinafter, each component will be described.

<[A] Polymer>

[A] The polymer is a polymer having a structural unit containing an acid-dissociable group (hereinafter also referred to as "structural unit (I)"). The solubility of the [A] polymer in the developing solution is changed by the action of an acid produced by the [B] acid generator described later. Therefore, the [A] polymer functions as a usual base polymer. Further, the term "base polymer" means a polymer which is a main component of a polymer constituting a resist pattern formed by a photoresist composition, and preferably means a total of all polymers constituting a resist pattern. 50% by mass or more of the polymer.

The polymer [A] preferably contains, in addition to the structural unit (I), at least a group selected from the group consisting of a lactone structure, a cyclic carbonate structure and a sultone structure, within a range not impairing the effects of the present invention. One type of structural unit (hereinafter also referred to as "structural unit (II)"). The polymer [A] may have one or two or more of these structural units. [A] The polymer may be a random copolymer or a block copolymer.

<structural unit (I)>

The structural unit (I) is a structural unit containing an acid-dissociable group. As for the structural unit (I), there is no particular limitation as long as it contains an acid-dissociable group. The "acid dissociable group" is a group which is substituted with a hydrogen atom such as a hydroxyl group or a carboxyl group, and which is dissociated in the presence of an acid. Thereby, the above structural unit generates a polar group by the action of an acid.

As the acid-dissociable group, for example, a group as a hydrogen atom of a substituted hydroxyl group is exemplified by a third butoxycarbonyl group, a tetrahydropyranyl group, a tetrahydrofuranyl group, a (thiotetrahydropyranylamine sulfonylamino)methyl group, (thiotetrahydrofuran). A methyl group or alkoxy group-substituted methyl group, an alkylsulfonyl group-substituted methyl group, and the like, and a group which substitutes a hydrogen atom of a carboxyl group is exemplified by a tertiary alkyl group. The alkoxy group (substituent group) in the methyl group substituted with an alkoxy group is, for example, an alkoxy group having 1 to 4 carbon atoms. Further, the alkyl group (substituent group) in the methyl group substituted with an alkylsulfonyl group is, for example, an alkyl group having 1 to 4 carbon atoms. The carbon number of the tertiary alkyl group is preferably from 4 to 30, more preferably from 4 to 20. Further, the tertiary alkyl group may be any of a chain hydrocarbon group, an alicyclic hydrocarbon group, and an alicyclic structure.

The structural unit (I) is preferably a structural unit represented by the following formula (3). By allowing the polymer [A] to have the above structural unit, the polar group can be easily produced by an acid, and the compatibility of the [A] polymer with the [B] acid generator can be improved.

In the above formula (3), R ⁹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ¹⁰ is a chain hydrocarbon group having 1 to 10 carbon atoms. R ¹¹ and R ¹² each independently represent a chain hydrocarbon group having 1 to 10 carbon atoms or an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a ring carbon in which the groups are bonded to each other and the carbon atoms bonded thereto Number 3~20 alicyclic structure.

From the viewpoint of improving the copolymerizability of the monomer having the above structural unit, R ⁹ is preferably a hydrogen atom or a methyl group, more preferably a methyl group.

The above-mentioned chain hydrocarbon group having 1 to 10 carbon atoms represented by R ¹⁰ , R ¹¹ and R ¹² is exemplified by, for example, a methyl group, an ethyl group, a n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group or a second butyl group. , tert-butyl, n-pentyl, isopentyl, second amyl, neopentyl, third amyl, n-hexyl, isohexyl, n-heptyl, isoheptyl, n-octyl, isooctyl, An alkyl group such as a fluorenyl group, an isodecyl group, a n-decyl group or an isodecyl group. The above-mentioned chain hydrocarbon group is preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group, an ethyl group or an isopropyl group, more preferably a methyl group.

The monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by R ¹¹ and R ¹² is exemplified by a monocyclic alicyclic hydrocarbon group such as a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group or a cyclooctyl group. a polycyclic alicyclic hydrocarbon group such as a norbornene group, an isobornyl group, an adamantyl group, a tricyclodecanyl group or a tetracyclododecyl group. The above alicyclic hydrocarbon group is preferably a cyclopentyl group, a cyclohexyl group, a norbornyl group, an isobornyl group or an adamantyl group, more preferably a cyclopentyl group or an adamantyl group. The carbon number of the above R ¹¹ and R ¹² is preferably from 4 to 15, more preferably from 4 to 12.

The alicyclic structure having 3 to 20 carbon atoms which is bonded to the above-mentioned R ¹¹ and R ¹² together with the bonded carbon atoms is exemplified by, for example, a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, and a cyclooctane. A monocyclic alicyclic hydrocarbon group such as a structure; a polycyclic alicyclic hydrocarbon group such as a norbornane structure or an adamantane structure; The alicyclic structure is preferably a cyclopentane structure, a cyclohexane structure, a norbornane structure, or an adamantane structure, and more preferably a cyclopentane structure or an adamantane structure. The carbon number of the above R ¹¹ and R ¹² is preferably from 4 to 15, more preferably from 4 to 12.

The structural unit (I) is exemplified by a structural unit represented by the following formulas (4-1) to (4-4).

In the above formulae (4-1) to (4-4), R ⁹ to R ¹² are synonymous with the above formula (3). And r is an integer from 1 to 4.

Construction sheet represented by the above formula (3) or (4-1) to (4-4) The bit number is listed as a structural unit represented by the following formula, for example.

In the above formula, R ⁹ is synonymous with the above formula (3).

The structural unit (I) is preferably a structural unit represented by the above formula (4-1) and a structural unit represented by the formula (4-2), more preferably derived from 1-alkyl-1 (meth)acrylate. a structural unit of cyclopentyl ester derived from a structural unit of 2-alkyl-2-adamantyl (meth)acrylate. And, the structural unit derived from 1-methyl-1-cyclopentyl-(meth) acrylate is further It is preferably a structural unit derived from 1-ethyl-1-cyclopentyl (meth)acrylate, a structural unit derived from 2-methyl-2-adamantyl (meth)acrylate, derived from (meth) The structural unit of 2-isopropyl-2-adamantyl acrylate. Further, (meth) acrylate means acrylate or methacrylate.

The content ratio of the structural unit (I) is preferably from 20 mol% to 80 mol%, more preferably from 40 mol% to 70 mol%, based on the total structural unit of the polymer [A]. By setting the content ratio to the above range, there is a tendency that the photoresist composition can be dissociated in a sufficient amount of acid. When the content ratio of the structural unit (I) is less than the above lower limit, the pattern formation property of the photoresist composition may be lowered. When the content ratio of the structural unit (I) exceeds the above range, the adhesion of the formed resist pattern may be lowered.

<Structural Unit (II)>

The structural unit (II) is a structural unit containing at least one selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure. [A] The polymer can be adjusted to have solubility in a developing solution by further having a structural unit (II). Moreover, the adhesion between the resist pattern formed by the photoresist composition and the substrate can be improved.

The structural unit (II) is exemplified by a structural unit represented by the following formula, and the like.

In the above formula, R ¹³ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

The above R ^{13 is} preferably a methyl group in the above.

The structural unit (II) in this structure contains a lactone structure The structural unit, the structural unit containing the sultone structure is preferably, more preferably a structural unit containing a lactone structure, more preferably a structural unit containing a norbornene lactone structure, preferably derived from (meth)acrylic acid. The structural unit of borneol lactone.

The content ratio of the structural unit (II) is preferably from 0 mol% to 80 mol%, more preferably from 20 mol% to 80 mol%, and more preferably to all structural units constituting the polymer [A]. Good 30% %~70%. By setting the content ratio of the structural unit (II) to the above range, the solubility of the polymer [A] in the developing solution can be further improved. In addition, the adhesion between the resist pattern formed by the photoresist composition and the substrate can be further improved. When the content ratio of the structural unit (II) exceeds the above upper limit, the pattern formation property of the photoresist composition may be lowered.

<Other structural units>

The [A] polymer may contain other structural units in addition to the above structural units (I) and (II). Other structural units are exemplified by, for example, a non-acid dissociable structural unit containing an alicyclic hydrocarbon group, a structural unit having a polar group, and the like. The content ratio of the other structural unit is usually 30 mol% or less, preferably 20 mol% or less, based on the entire structural unit of the polymer [A].

The content of the [A] polymer in the resist composition is usually 70% by mass or more, preferably 75% by mass or more based on the total solid content. When the content of the polymer [A] is less than the above lower limit, the pattern formation property of the photoresist composition may be lowered. Moreover, the photoresist composition can also One or two or more kinds of [A] polymers are contained.

<[A] Polymer Synthesis Method>

The [A] polymer can be synthesized, for example, by polymerizing a monomer which obtains each structural unit in a suitable solvent using a radical polymerization initiator.

The above radical initiator may, for example, be azobisisobutyronitrile (AIBN), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2' -Azobis(2-cyclopropylpropionitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyric acid dimethyl ester, etc. A nitrogen-based radical initiator; a peroxide-based radical initiator such as benzammonium peroxide, tert-butyl hydroperoxide or cumyl hydroperoxide. As the above-mentioned radical polymerization initiator, among these, AIBN, dimethyl 2,2'-azobisisobutyrate is preferred, and AIBN is more preferred. These radical initiators may be used alone or in combination of two or more.

The solvent used in the above polymerization is exemplified by, for example, an alkane such as n-pentane, n-hexane, n-heptane, n-octane, n-decane or n-decane; cyclohexane, cycloheptane, cyclooctane, and decahydrogen; Naphthenes such as naphthalene and norbornane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene and cumene; chlorobutanes, bromohexanes, dichloroethanes, hexamethylene Halogenated hydrocarbons such as dibromo and chlorobenzene; saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, isobutyl acetate, methyl propionate; Ketones such as acetone, 2-butanone, 2-pentanone, 4-methyl-2-pentanone, and 2-heptanone; ethers such as tetrahydrofuran, dimethoxyethane, and diethoxyethane; methanol An alcohol such as ethanol, 1-propanol, 2-propanol or 4-methyl-2-pentanol. The above solvent is preferably 2-butanol. The solvent used in the polymerization may be used singly or in combination of two or more.

The reaction temperature in the above polymerization is usually from 40 ° C to 150 ° C, preferably from 50 ° C to 120 ° C. The reaction time is usually from 1 hour to 48 hours, preferably from 1 hour to 24 hours.

[A] Polymer The polystyrene-equivalent weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) is not particularly limited, and is usually 1,000 or more and 500,000 or less, more preferably 2,000 or more and 400,000 or less, and more preferably It is 3,000 or more and 300,000 or less. When the Mw of the polymer [A] does not reach the above lower limit, the heat resistance of the obtained resist film may be lowered. When the Mw of the polymer [A] exceeds the above upper limit, the developability of the resist film may be lowered.

The ratio (Mw/Mn) of the Mw of the polymer to the polystyrene-equivalent number average molecular weight (Mn) measured by GPC is usually 1 or more and 5 or less, preferably 1 or more and 3 or less, more preferably 1 or more. 2 or less. When Mw/Mn exceeds the above upper limit, the heat resistance of the obtained resist film may be lowered.

The Mw and Mn of the polymer in the present specification are values measured by gel permeation chromatography (GPC) in accordance with the following conditions.

GPC column: 2 G2000HXL, 1 G3000HXL, 1 G4000HXL (above manufactured by TOSOH), column temperature: 40 ° C

Dissolution solvent: tetrahydrofuran

Flow rate: 1.0 ml / min

Sample concentration: 1.0% by mass

Sample injection amount: 100 μL

Detector: differential refractometer

Reference material: monodisperse polystyrene

[A] The low molecular weight component contained in the polymer means a component having a molecular weight of 1,000 or less. The content (% by mass) of the low molecular weight component is preferably less than 0.5% by mass, more preferably less than 0.2% by mass, even more preferably less than 0.1% by mass, from the viewpoint of the glass transition temperature of the [A] polymer.

The content (% by mass) of the low molecular weight component in the present specification is a value measured by high speed liquid chromatography (HPLC) under the following conditions.

HPLC column: Intersil ODS-25μm, 4.6mm ×250mm (made by JL Science Co., Ltd.)

Dissolution solvent: acrylonitrile / 0.1% by mass phosphoric acid aqueous solution

Flow rate: 1.0mL/min

Sample concentration: 1.0% by mass

Sample injection amount: 100 μL

Detector: differential refractometer

<[B] acid generator>

[B] The acid generator is an acid generator containing at least the compound (1). The acid generator refers to a compound which absorbs energy generated by exposure and which generates an acid such as a sulfonic acid. By using the photoresist composition containing the [A] polymer and the [B] acid generator, it is possible to form a resist pattern having a pattern shape such as a cross-sectional shape and excellent etching resistance while exhibiting excellent MEEF performance. The acid generator (B) may contain a compound other than the compound (1) or may be used as an acid generator composition, within the range not impairing the effects of the present invention. These compounds may be used alone or in combination of two or more.

Although the reason why the photoresist composition exhibits the above effects by the above configuration is not clear, for example, it is presumed as follows. That is, by making R ² the alkanediyl group or the above-mentioned fluorinated alkanediyl group, the compatibility of the [B] acid generator with the [A] polymer or the like can be improved, and the [B] acid generator can be made more uniform. Disperse in the resist film. As a result, the resist pattern is difficult to be a tip loss shape as in the past, and the cross-sectional shape is likely to be a rectangle. Further, it is considered that the acid diffusion property is appropriately controlled by the sulfonic acid ester structure and the appropriate polarity of the above R ² , so that the MEEF performance of the photoresist composition can be improved. Further, the number of fluorine atoms in R ² is small, that is, by making the fluorine number of the above R ² into the above range, the resistance to etching can be improved.

<Compound (1)>

The compound (1) is represented by the following formula (1).

R ¹⁰ -SO ₂ OR ² -SO ₃ ^- Q ⁺ (1)

In the above formula (1), R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 30 carbon atoms or a substituted or unsubstituted monovalent heterocyclic group having 3 to 30 ring atoms. R ² is an alkanediyl group having 1 to 30 carbon atoms or a fluorinated alkanediyl group having a fluorine number of less than 2 to 30 carbon atoms. Q ⁺ is a monovalent photodecomposable organic cation.

The above carbon number means the number of carbons contained in the hydrocarbon group, and does not contain the carbon number contained in any substituent. Further, the number of ring atoms refers to the number of carbon atoms and hetero atoms contained in the heterocyclic group, and does not include the number of carbon atoms contained in any substituent.

The above compound (1) contains an anion and a photodecomposable organic cation (Q ⁺ ). The "photodecomposable organic cation" is a cation containing a carbon atom which can be decomposed by exposure to generate a proton.

Since R ¹ is the above hydrocarbon group or the above heterocyclic group, excellent compatibility with the [A] polymer or the [E] solvent can be ensured. When the number of carbon atoms of the hydrocarbon group or the number of ring atoms of the heterocyclic group exceeds the above upper limit, the compatibility is lowered.

The above hydrocarbon group is exemplified by, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, t-butyl, n-pentyl, isopentyl, and second pentyl. , neopentyl, third amyl, n-hexyl, isohexyl, n-heptyl, isoheptyl, n-octyl, isooctyl, n-decyl, isodecyl, n-decyl, isodecyl, etc. a monocyclic cycloalkyl group such as cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl or cyclooctyl; norbornyl, isobornyl, adamantyl, tricyclodecyl, tetracycline a polycyclic cycloalkyl group such as a dialkyl group; an alkenyl group such as a vinyl group or a 1-propen-1-yl group; an alkynyl group such as an ethynyl group or a propynyl group; a phenyl group, a naphthyl group, a biphenyl group, an anthracenyl group or a fluorenyl group An aryl group such as phenanthryl; an aralkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group or a 2-naphthylethyl group.

The carbon number of the hydrocarbon group is preferably from 1 to 20, more preferably from 1 to 15.

The above heterocyclic group is exemplified by, for example, furyl, pyrrolyl, thienyl, oxazolinyl, isoxazolinyl, imidazolyl, thiazolyl, isothiazolyl, pyridyl, pyrimidinyl, tetrazolyl, pyrazole. Aromatic heterocyclic group (ie, heteroaryl) such as pyridyl, pyrazinyl, thiadiazolyl, dibenzofuranyl; piperidinyl, tetrahydropyranyl, tetrahydrofuranyl, oxacyclo An aliphatic heterocyclic group such as a butyl group, an azetidinyl group, a pyrrolidinyl group, a morpholinyl group, a thiomorpholinyl group, a dioxolyl group or a piperazinyl group.

The number of ring atoms of the heterocyclic group is preferably from 3 to 20, more preferably from 3 to 15.

The above hydrocarbon group and heterocyclic group may be substituted for a part or all of the hydrogen atoms by any substituent, within the range not impairing the effects of the present invention. The above substituent is not particularly limited as long as the desired physical properties are obtained, and examples thereof include an alkoxy group, a hydroxyl group, an aldehyde group, a carboxyl group, a carbonyl group, a decylamino group, a quinone imine group, an amine group, an imido group, a cyano group, and an even group. A conventional group such as a nitrogen group, an azide group, a thiol group, a sulfo group, a nitro group, an ether group, an ester group, a group having a lactone structure, an alkylcarbonyl group, an oxo group or a halogen atom. The above substituent is preferably an oxo group in the above. That is, the above R ¹ preferably contains a carbonyl group.

The above R ^{1 is} preferably a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aromatic heterocyclic group, more preferably an unsubstituted alkyl group, a substituted cycloalkyl group. The unsubstituted aromatic heterocyclic group is preferably an unsubstituted alkyl group having 1 to 4 carbon atoms, a cycloalkyl group substituted by an oxo group, and an aromatic heterocyclic group having an oxygen atom as a constituent atom. Preferably, it is methyl, n-butyl, 10-camphoryl, dibenzofuranyl.

The above R ² is an alkanediyl group having 1 to 30 carbon atoms or a fluorinated alkanediyl group having a carbon number of 2 to 30 and a carbon number of 2 to 30, preferably a fluorinated alkane having a fluorine number of less than a carbon number of 2 to 30 carbon atoms. Second base. When the number of carbon atoms of the hydrocarbon group or the number of ring atoms of the heterocyclic group exceeds the above upper limit, the solubility in a solvent is lowered.

The above alkanediyl groups are exemplified by, for example, a methane hydrocarbon diyl group, an ethane hydrocarbon diyl group, a propane hydrocarbon diyl group, a butane hydrocarbon diyl group, a pentane hydrocarbon diyl group, a hexane hydrocarbon diyl group, a heptane diyl group, an octane diyl group, a decane hydrocarbon. Dibasic, decane diyl and the like.

The fluorinated alkanediyl group is exemplified by a group in which one of the hydrogen atoms of the alkanediyl group is substituted with a fluorine atom, and a fluorine atom is less than a carbon number. When the fluorine number is in the above range, it is presumed that the [B] acid generator has excellent properties of both the lipophilicity derived from the hydrocarbon moiety and the polarity derived from the fluorine atom.

The carbon number of the above alkanediyl group is preferably from 1 to 20, more preferably from 1 to 10. Further, the carbon number of the fluorinated alkanediyl group is preferably from 2 to 20, more preferably from 2 to 10.

The alkanediyl and fluorinated alkanediyl groups may be linear or may be With side chains.

The above R ^{2 is} preferably a fluorinated alkanediyl group, and the fluorine atom of the fluorinated alkanediyl group is 2 or more. In this case, the strength of the acid generated can be increased, and as a result, the resist pattern can be more excellent in pattern shape and etching resistance while exhibiting more excellent MEEF performance.

The fluorinated alkanediyl group having a fluorine number of 2 or more is exemplified by, for example, a fluorine atom substituted with two or more propane hydrocarbon diyl groups, a butane hydrocarbon diyl group, a pentane hydrocarbon diyl group, a hexane hydrocarbon diyl group, a heptane diyl group, and an octane hydrocarbon group. Any hydrogen atom such as a base, a decane diyl group or a decane hydrocarbon group is formed.

The above fluorine number is preferably from 2 to 10, more preferably from 2 to 8. Further, the fluorine number is smaller than the carbon number of the fluorinated alkanediyl group.

The above fluorinated alkanediyl group is preferably represented by the following formula (i).

[11]-R ³ -CF ₂ - (i)

In the above formula (i), R ³ is an alkanediyl group having 3 or more carbon atoms or a fluorinated alkanediyl group having 3 or more carbon atoms.

By having the [B] acid generator having the group represented by the above formula (i), the acid strength generated can be further increased, and as a result, the above characteristics of the photoresist composition can be further improved. Further, the -CF ₂ - group of the above formula (i) is bonded to the -SO ₃ ^- group of the above formula (1).

The above R ^{3 is} exemplified by, for example, a propane hydrocarbon diyl group in which one hydrogen atom is substituted or unsubstituted with a fluorine atom, a butane hydrocarbon diyl group in which one or two hydrogen atoms are substituted or unsubstituted by a fluorine atom, and one to three a pentane hydrocarbon diyl group in which a hydrogen atom is substituted or unsubstituted with a fluorine atom, a hexane hydrocarbon diyl group in which one to four hydrogen atoms are substituted or unsubstituted by a fluorine atom, and one to five hydrogen atoms are substituted by a fluorine atom or not a substituted heptane diyl group, a 1-6 alkyl group substituted with a fluorine atom or a fluorine atom substituted by a fluorine atom, or a decane diyl group having 1 to 7 hydrogen atoms substituted or unsubstituted by a fluorine atom, A decane diyl group in which one to eight hydrogen atoms are substituted or unsubstituted with a fluorine atom. Further, any hydrogen atom may be substituted with a fluorine atom within a range not impairing the effects of the present invention.

The carbon number of the above R ³ is preferably from 3 to 29, more preferably from 3 to 19, still more preferably from 3 to 9, in any of the alkanediyl group and the fluorinated alkanediyl group. When the carbon number is in the above range, the compound (1) tends to exhibit more excellent compatibility with the [A] polymer.

The above R ^{3 is} preferably a propane hydrocarbon diyl group in which one hydrogen atom is substituted or unsubstituted by a fluorine atom, a butane hydrocarbon diyl group in which one or two hydrogen atoms are substituted or unsubstituted by a fluorine atom, and one to three a pentane hydrocarbon diyl group in which a hydrogen atom is substituted or unsubstituted with a fluorine atom, a hexane hydrocarbon diyl group in which one to four hydrogen atoms are substituted or unsubstituted by a fluorine atom, and one to five hydrogen atoms are substituted by a fluorine atom or not Substituted heptane diyl, one to six hydrogen atoms substituted or unsubstituted octane diyl, more preferably propane dienyl, difluoropropane diyl, difluorooctane diyl , hexafluorooctane diyl.

The anion of the compound (1) is exemplified by an anion represented by the following formulas (5-1) to (5-14). These anions may be used singly or in combination of two or more.

The anion of the above compound (1) is preferably the above formulas (5-1), (5-4), (5-5), (5-6)' (5-7), (5-8) and The anion represented by 5-11) is more preferably an anion represented by the above formula (5-1).

The Q ⁺ is not particularly limited as long as it is a monovalent photodecomposable organic cation, and is exemplified by a conventional photodecomposable organic cation.

The photodecomposable organic cation is exemplified by, for example, a cerium ion, a cerium ion, an imidazolium ion, a pyridinium ion, an ammonium ion, a pyrrolidinium ion, a cerium ion, or the like. As for the photodecomposable organic cation, among these, ruthenium ions and ruthenium ions are preferred. When the photodegradable organic cation is any of cerium ions and cerium ions, the above characteristics of the MEEF performance of the photoresist composition tend to be improved. These photodecomposable organic cations may be used singly or in combination of two or more.

The Q ^{+ is} more preferably at least one selected from the group consisting of a phosphonium cation represented by the following formula (2-1) and a phosphonium cation represented by the following formula (2-2). It can improve the sensitivity of the resist pattern.

In the above formula (2-1), R ⁴ , R ⁵ and R ^{6 are} each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or Any two or more of these groups are bonded to each other to form a ring structure together with the bonded sulfur atoms.

In the above formula (2-2), R ⁷ and R ⁸ are each independently a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms or a substituted or unsubstituted sum of carbon atoms of an aryl group having 6 to 30, or represents a group such A ring structure formed by bonding together with the iodine atoms bonded thereto.

The above carbon number means the number of carbons contained in each functional group, and does not contain the carbon number contained in any substituent.

When the carbon number of the alkyl group or the aryl group exceeds the above upper limit, the compatibility between the compound and the [A] polymer or the solubility in the [E] solvent may be lowered.

Any of the substituents which R ⁴ to R ⁸ may have are exemplified by, for example, a conventional functional group exemplified in R ¹ .

The alkyl group contained in the above R ⁴ , R ⁵ and R ⁶ is exemplified by, for example, those exemplified as R ¹ . The carbon number of the above alkyl group is preferably from 1 to 15, more preferably from 1 to 10.

The aryl group contained in the above R ⁴ , R ⁵ and R ⁶ is exemplified by, for example, those exemplified as R ¹ . As the above aryl group, among these, a phenyl group is preferred. The carbon number of the above aryl group is preferably from 6 to 25, more preferably from 6 to 20.

The above R ⁴ , R ⁵ and R ⁶ may also represent a ring structure in which any two or more of these groups are bonded to each other and to the sulfur atom to which they are bonded. The ring structure is exemplified by a structure in which one carbon atom in the alicyclic structure is substituted with a sulfur atom. The number of ring atoms is preferably from 3 to 20, more preferably from 3 to 15. When the number of ring atoms is in the above range, there is a tendency to increase the sensitivity of the resist pattern.

The above phosphonium cation is exemplified by, for example, a triphenylphosphonium cation Cyclohexyl 2-oxocyclohexylmethylphosphonium cation, dicyclohexyl 2-oxocyclohexylphosphonium cation, 2-oxocyclohexyldimethylphosphonium cation, 4-hydroxy-1-naphthyldimethylsulfonium cation A conventional cation such as a diphenyl-4-hydroxyphenylphosphonium cation or a 4-tert-butoxyphenyldiphenylphosphonium cation. The above phosphonium cation is preferably a triphenylphosphonium cation in the above.

The alkyl group contained in the above R ⁷ and R ^{8 is} exemplified by, for example, those exemplified as R ¹ . The carbon number of the above alkyl group is preferably from 1 to 15, more preferably from 1 to 10.

The aryl group contained in the above R ⁷ and R ⁸ is exemplified by, for example, those exemplified as R ¹ . The above aryl is preferably a phenyl group based on the above. The carbon number of the above aryl group is preferably from 6 to 25, more preferably from 6 to 20.

The above R ⁷ and R ⁸ may also represent a ring structure in which these groups are bonded to each other and the iodine atoms bonded thereto. The ring structure is exemplified by a structure in which one carbon atom in the alicyclic structure is substituted with an iodine atom. The number of ring atoms is preferably from 3 to 20, more preferably from 3 to 15. When the number of ring atoms is in the above range, there is a tendency to increase the sensitivity of the resist pattern.

The above ruthenium cation is exemplified by a conventional cation such as a diphenylphosphonium cation, a bis(4-t-butylphenyl)phosphonium perfluorooctane sulfonate or a bis(4-t-butylphenyl)fluorene. The above phosphonium cation is preferably a diphenylphosphonium cation in the above.

The compound (1) is exemplified by, for example, a combination of the above anion and a photodecomposable organic cation.

The above compound (1) is preferably a compound represented by the following formula.

The content of the compound (1) contained in the acid generator is not particularly limited, but is usually 10% by mass or more, preferably 20% by mass or more and 100% or less. When the content rate is less than the above lower limit, the cross-sectional shape of the resist pattern may be lowered.

The acid generator other than the compound (1) contained in the acid generator is exemplified by, for example, an onium salt compound other than the compound (1), a halogen-containing compound, a diazoketone compound, an anthraquinone compound, a sulfonic acid compound, and a heavy A nitrogen-methane-based compound, a nitrobenzylsulfonate-based compound, an imidosulfonate-based compound, or the like.

The onium salt compound is exemplified by, for example, a phosphonium salt and a phosphonium salt other than the compound (1), and a phosphonium salt, a diazonium salt, a pyridinium salt or the like, specifically, diphenylsulfonium trifluoromethanesulfonate, and Phenyl quinone nonafluorobutane sulfonate, diphenyl fluorene perfluoro-n-octane sulfonate, diphenyl hydrazine 2-bicyclo[2.2.1]heptan-2-yl-1,1,2,2 -tetrafluoroethane sulfonate, bis(4-tert-butylphenyl)phosphonium trifluoromethanesulfonate, bis(4-t-butylphenyl)phosphonium nonafluorobutane sulfonate, double (4-tert-butylphenyl)phosphonium perfluorooctane sulfonate, bis(4-t-butylphenyl)phosphonium 2-bicyclo[2.2.1]hept-2-yl-1,1, 2,2-tetrafluoroethane sulfonate, cyclohexyl 2-oxocyclohexylmethyl fluorene trifluoromethanesulfonate, dicyclohexyl 2-oxocyclohexyl fluorene trifluoromethane sulfonate, 2-oxygen Cyclohexyldimethylsulfonium trifluoromethanesulfonate and the like.

The halogen-containing compound is exemplified by, for example, a halogenated alkyl group-containing hydrocarbon compound, a halogenated alkyl group-containing heterocyclic compound, and the like. Specifically, for example, phenylbis(trichloromethyl)-s-triazine, 4-methoxyphenylbis(trichloromethyl)-s-triazine, 1-naphthylbis(trichloromethane) Base)-s-triazine, etc. a s-triazine derivative; 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane, and the like.

The diazoketone compound is exemplified by, for example, a 1,3-diketone-2-diazo compound, a diazonium quinone compound, a diazonaphthoquinone compound, or the like. Specifically, for example, 1,2-naphthoquinonediazide-4-sulfonium chloride, 1,2-naphthoquinonediazide-5-sulfonyl chloride, 2,3,4,4'-tetrahydroxydiphenyl Ketone 1,2-naphthoquinonediazide-4-sulfonate, 1,2-naphthoquinonediazide-5-sulfonate, 1,1,1-cis (4-hydroxyphenyl)ethane 1 2-naphthoquinonediazide-4-sulfonate, 1,2-naphthoquinonediazide-5-sulfonate, and the like.

The ruthenium compound is exemplified by, for example, β-ketooxime, β-sulfonylhydrazine, or an α-diazonium compound of the compounds. Specifically, for example, 4-paraphenylethylhydrazine, mesitylene phenethyl hydrazine, bis(phenylsulfonyl)methane, and the like are exemplified.

The sulfonic acid compound is exemplified by, for example, an alkylsulfonate, an alkylsulfonium iminoamine, a haloalkylsulfonate, an arylsulfonate, an imidosulfonate or the like.

Specifically, it is exemplified by benzoin methanesulfonate, pyrogallol (trifluoromethanesulfonate), nitrobenzyl-9,10-diethoxyindole-2-sulfonate, and three Fluoromethanesulfonylbicyclo[2.2.1]hept-5-ene-2,3-dicarbodiimide, nonafluoro-n-butanesulfonylbicyclo[2.2.1]hept-5-ene-2, 3-dicarbodiimide, perfluoro-n-octanesulfonylbicyclo[2.2.1]hept-5-ene-2,3-dicarbodiimide, 2-bicyclo[2.2.1]heptane- 2-yl-1,1,2,2-tetrafluoroethanesulfonylbicyclo[2.2.1]hept-5-ene-2,3-dicarbodiimide, N-(trifluoromethanesulfonate) Oxy) succinimide, N-(nonafluoro-n-butane sulfonyloxy) succinimide, N-(perfluoro-n-octane sulfonyloxy) amber Yttrium, N-(2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonyloxy) succinimide, 1,8-naphthalene dicarboxylate Barium imide trifluoromethanesulfonate, octadecyl n-butane sulfonate 1,8-naphthalene dicarboxylate, perfluoro-n-octane sulfonate of 1,8-naphthalene dicarboxylate Wait.

These compounds may be used alone or in combination of two or more. The amount of the acid generator to be added is usually 0.1 parts by mass to 20 parts by mass, preferably 0.5 parts by mass to 15 parts by mass, per 100 parts by mass of the [A] polymer. When the amount is within the above range, there is a tendency to ensure excellent compatibility between the [A] polymer and the [B] acid generator. When the compounding amount exceeds the above upper limit, the transparency of the photoresist composition to the exposed light is lowered, and it is difficult to obtain a resist pattern having the desired characteristics described above. When the amount of the compound does not reach the above lower limit, the sensitivity or developability of the photoresist composition is lowered.

<Method for producing acid generator>

The acid generator containing the compound (1) is not particularly limited and can be produced according to a conventional method.

When an example of the production method of the compound (1) is exemplified, the above compound obtained by using Br-R ² -OH (R ² is synonymous with the above formula (1)) as a starting material can be obtained by a production method having the following steps. The step of heating the above starting material in an aqueous solution of acetonitrile in the presence of sodium dithionite and sodium hydrogencarbonate, heating the aqueous layer obtained in the previous step in the presence of hydrogen peroxide water and disodium tungstate, before a step of adding a photodegradable organic cation (Q ⁺ ) chloride (Q ⁺ synonymous with the above formula (1)), dichloromethane and water to the aqueous layer obtained in the first step, stirring at room temperature, and before Adding triethylamine and 4-dimethylaminopyridine to the dichloromethane solution obtained in one step, cooling, and then dropwise adding a solution of R ¹ -SO ₂ Cl (R ¹ is synonymous with the above formula (1)) And the step of stirring. The conditions such as temperature, pressure, time, or other steps of the apparatus in each step are not particularly limited, and are appropriately set depending on the materials used. The number of stages in each step is not particularly limited and can be carried out in one stage or in multiple stages.

<arbitrary composition>

The resist composition may further contain a [C] acid diffusion controlling agent, [D] a fluorine atom-containing polymer, and [E] a solvent as suitable components, and may also contain a range which does not impair the effects of the present invention. [F] partialization accelerator, surfactant, alicyclic skeleton compound, sensitizer, crosslinking agent, surfactant, dissolution inhibitor, plasticizer, stabilizer, colorant, antihalation agent, dye, A pigment, a secondary auxiliary agent, an alkali-soluble resin, a low molecular alkali solubility control agent having an acid dissociable protecting group, a basic compound, a dissolution inhibitor, a storage stabilizer, an antifoaming agent, and the like. The amount of other ingredients may be appropriately determined depending on the purpose. These components are described below.

<[C] Acid Diffusion Control Body>

[C] The acid diffusion control body controls the diffusion of acid generated by exposure in the resist film, and exerts the effect of suppressing poor chemical reaction in the unexposed area. Further, the storage stability of the obtained photoresist composition is further improved, and the resolution as a resist is further improved, and the line width variation of the resist pattern due to the change in the leaving time from the exposure to the development treatment can be suppressed, and the process can be obtained. A photoresist composition with excellent stability. [C] The acid diffusion control body may be in the form of a free compound in the form of a free compound (hereinafter referred to as "[C] acid diffusion controlling agent"), or may be incorporated as part of the polymer. The form can also be the form of the two.

The [C] acid diffusion controlling agent is exemplified by, for example, an amine compound, a guanamine group-containing compound, a urea compound, a nitrogen-containing heterocyclic compound, and the like.

The amine compounds are exemplified by, for example, mono(cyclo)alkylamines; di(cyclo)alkylamines; tri(cyclo)alkylamines; substituted alkylanilines or derivatives thereof; ethylenediamine, N, N , N', N'-tetramethylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodi Phenyl ether, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylamine, 2,2-bis(4-aminophenyl)propane, 2-(3- Aminophenyl)-2-(4-aminophenyl)propane, 2-(4-aminophenyl)-2-(3-hydroxyphenyl)propane, 2-(4-aminophenyl) -2-(4-hydroxyphenyl)propane, 1,4-bis(1-(4-aminophenyl)-1-methylethyl)benzene, 1,3-bis(1-(4-amine) Phenyl)-1-methylethyl)benzene, bis(2-dimethylaminoethyl)ether, bis(2-diethylaminoethyl)ether, 1-(2-hydroxyethyl)- 2-imidazolidinone, 2-quinoxaline alcohol, N,N,N',N'-indole (2-hydroxypropyl)ethylenediamine, N,N,N',N",N"-penta Base diethylene triamine and the like.

As the compound containing a guanamine group, for example, an amine compound containing N-tert-butoxycarbonyl group, formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, acetamide, benzamide, pyrrolidone, N-methylpyrrolidone , N-ethinyl-1-adamantanamine, tris(2-hydroxyethyl) isocyanurate, and the like.

Urea compounds are exemplified by, for example, urea, methyl urea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea , tri-n-butyl thiourea, and the like.

The nitrogen-containing heterocyclic compound is exemplified by, for example, imidazoles; pyridines; piperazines; pyrazine, pyrazole, pyridazine, quinazoline, anthracene, pyrrolidine, piperidine, piperidine ethanol, 3-piperidinyl-1 , 2-propanediol, morpholine, 4-methylmorpholine, 1-(4-morpholinyl)ethanol, 4-ethylmercaptomorpholine, 3-(N-morpholinyl)-1,2-propanediol, 1,4-Dimethylpiperazine, 1,4-diazabicyclo[2.2.2]octane, N-t-butoxycarbonyl 4-hydroxypiperidine, and the like.

The [C] acid diffusion controlling agent is preferably N-tert-butoxycarbonyl 4-hydroxypiperidine in the above.

These [C] acid diffusion control bodies may be used singly or in combination of two or more. When the [C] acid diffusion controlling agent is the [C] acid diffusion controlling agent, it is preferably less than 15 parts by mass, more preferably less than 10 parts by mass based on 100 parts by mass of the [A] polymer. Parts by mass. When the content of the [C] acid diffusion controlling agent is at least the above, the sensitivity as a resist may be lowered.

<[D] Polymer of fluorine atom>

The photoresist composition may further contain a fluorine atom in a higher content than [A] A polymer of a polymer (hereinafter also referred to as "[D] a polymer of a fluorine atom"). When the photoresist composition contains the polymer of [D] fluorine atom, the liquid elution exposure is improved even when the hydrophobicity of the resist film is increased, and the substance elution inhibition property is excellent, and the resist film and the liquid immersion liquid are sufficiently improved. When the contact angle is retracted and the effect of not allowing water droplets to remain during scanning exposure at a high speed, the use of the photoresist composition for immersion exposure is high.

[D] The polymer form of the fluorine atom is not particularly limited as long as it has a fluorine atom, and is, for example, a structure in which a fluorinated alkyl group is bonded to the main chain; a structure in which a fluorinated alkyl group is bonded to a side chain; The structure of the fluorinated alkyl group is bonded to the side chain.

The monomer having a structure in which a fluorinated alkyl group is bonded to the main chain is exemplified by, for example, an α-trifluoromethyl acrylate compound, a β-trifluoromethyl acrylate compound, an α,β-trifluoromethyl acrylate compound, and a compound. A compound in which a hydrogen atom of the above ethylene moiety is substituted with a fluorinated alkyl group such as a trifluoromethyl group.

The monomer having a structure in which a fluorinated alkyl group is bonded to a side chain is exemplified by a fluorinated alkyl group or a derivative thereof, for example, an alicyclic olefin compound such as norbornene, which is exemplified by acrylic acid or methacrylic acid. The side chain is an ester compound of a fluorinated alkyl group or a derivative thereof, and a side chain (a site containing no double bond) of one or more kinds of olefins is a fluorinated alkyl group or a derivative thereof.

The monomer having a structure in which a fluorinated alkyl group is bonded to the main chain and the side chain is exemplified by, for example, α-trifluoromethacrylic acid, β-trifluoromethacrylic acid, α,β-trifluoromethacrylic acid, or the like. The chain is a fluorinated alkyl group or an ester compound thereof, and one or more hydrogen atoms of an ethylene moiety are subjected to fluorine such as a trifluoromethyl group. The side chain of the alkyl-substituted compound is substituted by a fluorinated alkyl group or a derivative thereof, and a hydrogen atom bonded to a double bond of one or more alicyclic olefin compounds is a fluorinated alkyl group such as a trifluoromethyl group. Substituted, and the side chain is a fluorinated alkyl group or a derivative thereof or the like. Further, the alicyclic olefin compound is a compound in which a part of the ring is a double bond.

As for the above structure, the structural unit represented by the following formula is preferable.

In the above formula, R ¹⁴ and R ¹⁵ each independently represent a hydrogen atom, a fluorine atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms and having at least one fluorine atom.

Further, the polymer of the [D] fluorine atom may have a structural unit having an acid dissociable group, a lactone structure, a cyclic carbonate structure, and a sultone structure, within a range not impairing the effects of the present invention. At least one structural unit selected from the group is selected as a structural unit other than the fluorine-containing structural unit. The structural unit is exemplified by, for example, those exemplified in the structural units (I) and (II) in the [A] polymer.

[D] The fluorine atom-containing polymer is preferably a copolymer containing a fluorine-containing structural unit and a structural unit containing an acid-dissociable group.

In the polymer of the fluorine atom-containing polymer, the content ratio of the fluorine-containing structural unit is preferably from 5 mol% to 100 mol% based on the total structural unit of the polymer constituting the fluorine atom-containing [D]. It is preferably 10% by mole to 80% by mole, and more preferably 20% by mole to 70% by mole. When the content exceeds the above upper limit, it may cause pattern collapse or pattern peeling. When the content ratio is less than the above lower limit, the substance dissolution inhibiting property may be lowered. [D] The polymer may be a random copolymer or a block copolymer.

Further, in the polymer of the fluorine atom-containing unit [D], the fluorine atom content is preferably from 1% by mass to 60% by mass, more preferably from 2% by mass to 25% by mass. When the fluorine atom content exceeds the above upper limit, there is a case where the formed resist pattern pattern collapses or the pattern is peeled off. When the fluorine atom content rate is less than the above upper limit, the substance elution inhibiting property may be lowered. The fluorine atom content in the polymer can be calculated from the structure of the polymer by ¹³ C-NMR.

These [D] fluorine atom-containing polymers can be used alone, Two or more types can be used in combination. The content of the polymer of the fluorine atom is preferably less than 15 parts by mass, more preferably less than 10 parts by mass, per 100 parts by mass of the [A] polymer. When the polymer content of the fluorine atom is at least the above, the desired resist properties may not be obtained.

The polymer of the above [D] fluorine atom is the same as the case of the polymer [A], and can be synthesized, for example, by polymerizing a monomer corresponding to each specific structural unit in a suitable solvent by using a radical polymerization initiator. .

<[E] Solvent>

The photoresist composition usually contains [E] a solvent. The solvent of the [E] to be used is not particularly limited as long as it dissolves at least the solvent of the [A] polymer and the [B] acid generator. As such solvents, for example, alcohols, ethers, diethylene glycol alkyl ethers, ethylene glycol alkyl ether acetates, alkylene glycol monoalkyl ethers, propylene glycol monoalkyl ether acetates can be used. And propylene glycol monoalkyl ether propionates, aromatic hydrocarbons, ketones, esters, guanamines, nitriles and mixed solvents thereof.

The solvent of the above [E] is exemplified by an alcohol such as benzyl alcohol or diacetone alcohol; and ethers such as tetrahydrofuran, diisopropyl ether, di-n-butyl ether, di-n-pentyl ether, diisoamyl ether, and di-n-hexane. Dialkyl ethers such as ethers; diethylene glycol alkyl ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethyl Glycol ethyl methyl ether or the like; ethylene glycol alkyl ether acetate is, for example, methyl cellosolve acetate, B a base of cellosolve acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monoethyl ether acetate, etc.; propylene glycol monoalkyl ethers are, for example, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, Propylene glycol monobutyl ether or the like; propylene glycol monoalkyl ether acetate is, for example, propylene glycol monomethyl ether acetate (propylene glycol monomethyl ether acetate), propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether Acetate or the like; propylene glycol monoalkyl ether propionate such as propylene glycol monomethyl ether propionate, propylene glycol monoethyl ether propionate, propylene glycol monopropyl ether propionate, propylene glycol monobutyl ether propionate, etc.; aromatic The hydrocarbons are, for example, toluene, xylene, etc.; the ketones are, for example, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 2-heptanone, 4-hydroxy-4-methyl-2-pentanone, etc. The esters are exemplified by, for example, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, 2- Ethyl hydroxy-2-methylpropionate, methyl hydroxyacetate, ethyl hydroxyacetate, butyl glycolate, methyl lactate, ethyl lactate, Butyl acrylate, butyl lactate, methyl 3-hydroxypropionate, ethyl 3-hydroxypropionate, propyl 3-hydroxypropionate, butyl 3-hydroxypropionate, 2-hydroxy-3-methylbutyric acid Methyl ester, methyl methoxyacetate, ethyl methoxyacetate, propyl methoxyacetate, butyl methoxyacetate, methyl ethoxyacetate, ethyl ethoxyacetate, acetoxyacetate Ester, butyl ethoxyacetate, methyl propoxyacetate, ethyl propoxyacetate, propyl propoxyacetate, butyl propoxyacetate, methyl butoxyacetate, ethyl butoxide , butyl butoxyacetate, butyl butoxyacetate, methyl 2-methoxypropionate, ethyl 2-methoxypropionate, 2-methoxy Propyl propionate, butyl 2-methoxypropionate, methyl 2-ethoxypropionate, ethyl 2-ethoxypropionate, etc.; guanamines such as formamidine, N-methyl group Indoleamine, N,N-dimethylformamide, N-methylacetamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, etc.; nitriles such as acetonitrile, C Nitrile and the like.

The solvent of the above [E] is preferably propylene glycol monoalkyl ether acetate or ketone, more preferably propylene glycol monomethyl ether or cyclohexanone.

These [E] solvents may be used singly or in combination of two or more. The content of the solvent of [E] is preferably from 500 parts by mass to 8,000 parts by mass, more preferably from 600 parts by mass to 7,000 parts by mass, per 100 parts by mass of the [A] polymer. When the content exceeds the above upper limit, the manufacturing cost may become high. When the content is less than the above lower limit, the [A] polymer or the like cannot be sufficiently dissolved.

<[F] partialization accelerator>

The photoresist composition may contain a [F] biasing accelerator having an effect of segregating the polymer of the above-mentioned [D] fluorine atom more efficiently on the surface of the resist film. By including the additive in the photoresist composition, the amount of the fluorine atom-containing polymer can be made smaller than in the related art. According to this, it is possible to further suppress the component self-resistance film from being dissolved in the liquid immersion liquid while maintaining the basic characteristics of the resist such as MEEF performance, LWR performance, and pattern collapse resistance, and to perform immersion exposure at a higher speed by high-speed scanning. Such additives are listed as, for example, γ- A lactone compound such as butyrolactone, a cyclic carbonate compound such as propylene carbonate, a nitrile compound such as succinonitrile or a polyhydric alcohol such as glycerin. The above additives are preferably γ-butyrolactone in these.

These [F] partialization accelerators may be used singly or in combination of two or more. The content of the [F] biasing accelerator is preferably from 1 part by mass to 100 parts by mass, more preferably from 2 parts by mass to 80 parts by mass, per 100 parts by mass of the [A] polymer. When the content exceeds the above upper limit, the manufacturing cost may become high. When the content is less than the above lower limit, it is necessary to increase the polymer of the [D] fluorine atom.

<Surfactant>

The surfactant has an effect of improving coatability, streaking property, developing property, and the like. As the surfactant, for example, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octyl phenyl ether, polyoxyethylene n-decyl phenyl ether, poly A nonionic surfactant such as ethylene glycol dilaurate or polyethylene glycol distearate, and the following trade names KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), POLYFLOW No. 75, and POLYFLOW No. 95 (above Kyoeisha Chemical Manufacturing Co., Ltd., EF TOP EF301, EF TOP EF303, EF TOP EF352 (above manufactured by TOHCHEM PRODUCTS), MEGAFAC F171, MEGAFAC F173 (above DIC), FLORARD FC430, FLORARD FC431 (above Sumitomo 3M) , ASAHI GUARD AG710, SURFLON S-382, SURFLON SC-101, SURFLON SC-102, SURFLON SC-103, SURFLON SC-104, SURFLON SC-105, SURFLON SC-106 (above, manufactured by Asahi Glass). These surfactants may be used singly or in combination of two or more.

<Compound containing an alicyclic skeleton>

The compound containing an alicyclic skeleton exhibits effects of improving dry etching resistance, pattern shape, adhesion to a substrate, and the like.

The compound containing an alicyclic skeleton is exemplified by adamantane derivatives such as 1-adamantanecarboxylic acid, 2-adamantanone, and 1-adamantanecarboxylic acid tert-butyl ester; tert-butyl deoxycholate, deoxygenated Deoxycholate esters such as tert-butoxycarbonyl methyl cholate and 2-ethoxyethyl deoxycholate; tert-butyl lithochate, third butoxycarbonyl methyl lithate, lithocholic acid 2 -lithocholate such as ethoxyethyl ester; 3-[2-hydroxy-2,2-bis(trifluoromethyl)ethyl]tetracycline [4.4.0.1 ^2,5 .1 ^7,10 ] Dioxane, 2-hydroxy-9-methoxycarbonyl-5-oxo-4-oxa-tricyclo[4.2.1.0 ^3,7 ]decane, and the like. These alicyclic skeleton-containing compounds may be used singly or in combination of two or more.

<sensitizer>

The sensitizer is an effect indicating an increase in the amount of acid generated by the [B] acid generator, and exhibits an effect of improving the "apparent sensitivity" of the resist composition.

Sensitizers are listed, for example, as oxazoles, acetophenones, diphenyls Ketones, naphthalenes, phenols, diacetyl, eosin, rose red, pyrenes, anthraquinones, phenothiazines, and the like. These sensitizers may be used alone or in combination of two or more.

<Modulation method of photoresist composition>

The method of preparing the photoresist composition is not particularly limited and can be carried out according to a conventional method. The photoresist composition can be prepared by, for example, mixing the [A] polymer, the [B] acid generator, and an optional component in a specific ratio in an organic solvent. Further, the photoresist composition can be used in a state of being dissolved or dispersed in a suitable organic solvent.

<Formation method of resist pattern>

The method for forming the resist pattern has the following steps: a step of forming a resist film (hereinafter also referred to as "resist film forming step"), and a step of exposing the resist film (hereinafter also referred to as "exposure step") And a step of developing the exposed resist film (hereinafter also referred to as "development step"), and the resist film is formed of the photoresist composition.

According to the resist pattern forming method, since the photoresist composition described above is used, it is possible to form a resist pattern having excellent cross-sectional shape rectangularness and etching resistance while exhibiting excellent MEEF performance. Hereinafter, each step will be described.

[Resistance film forming step]

The resist film forming step uses the photoresist composition to form a resist film. As the substrate on which the resist film is formed, for example, a germanium wafer, a germanium dioxide, a wafer coated with an antireflection film, or the like can be used. The coating method of the photoresist composition is exemplified by methods such as spin coating, casting coating, and roll coating. The coating film formed by the above coating is preferably subjected to pre-baking (PB) evaporation to remove the solvent in the coating film. The PB temperature is usually from 60 ° C to 140 ° C, preferably from 80 ° C to 120 ° C. The PB time is usually 5 seconds to 600 seconds, preferably 10 seconds to 300 seconds.

[Exposure step]

The exposure step exposes the resist film formed in the resist film formation step. This exposure is performed by irradiating the exposed light through a photomask or the like (as the case may be, a liquid immersion medium such as water). The light to be exposed is determined by, for example, visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light, X-ray, gamma ray, or the like, and charged particle rays such as an electron beam or an alpha ray. Further, as the light to be exposed, it is preferably far ultraviolet rays, extreme ultraviolet rays, electron beams, etc., more preferably ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm), EUV (13.5 nm). ), electron beam, and better ArF excimer laser light, electron beam.

After the above exposure, post-exposure bake (PEB) is preferably carried out, and in the exposed portion of the resist film, the acid dissociation of the [A] polymer which promotes the acid generated from the [B] acid generator by exposure is promoted. The dissociation of the base. borrow From the PEB, it is possible to surely produce poor solubility of the exposed portion (exposed portion) and the unexposed portion (unexposed portion) with respect to the developing liquid. The PEB temperature is usually from 50 ° C to 180 ° C, preferably from 80 ° C to 130 ° C. The PEB time is usually 5 seconds to 600 seconds, preferably 10 seconds to 300 seconds.

In the immersion exposure, in order to protect the liquid immersion liquid from direct contact with the resist film before the exposure step, a protective film for liquid immersion which is insoluble in the liquid immersion liquid may be provided on the resist film. The protective film for liquid immersion can be used as a solvent-peelable protective film which is peeled off by a solvent before the development step (see, for example, JP-A-2006-227632), and a developing liquid peeling type protective film which is simultaneously peeled off from the development of the developing step. (See, for example, International Publication No. 2005/069076, International Publication No. 2006/035790, etc.). However, from the viewpoint of the amount of treatment, a protective liquid for liquid immersion liquid immersion is preferably used.

[development step]

The developing step is to develop the exposed resist film in the exposure step. Thereby, a specific resist pattern is formed. The above development method may be alkali imaging or organic solvent imaging. Generally, a positive resist pattern is formed by an alkali developing system, and a negative resist pattern is formed by using an organic solvent developing system. After the above development, it is usually washed with a washing liquid such as water or alcohol, and dried.

As for the above-mentioned developing solution, in the case of alkali development, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium citrate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, and di-n-butyl are exemplified. Propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo [5.4.0] An aqueous alkaline solution obtained by dissolving at least one of a basic compound such as 7-undecene and 1,5-diazabicyclo-[4.3.0]-5-decene. As the above developing solution, in the above, a TMAH aqueous solution is preferred, and a 2.38 mass% TMAH aqueous solution is more preferred.

Further, in the case of developing an organic solvent, an organic solvent such as a hydrocarbon solvent, an ether solvent, an ester solvent, a ketone solvent or an alcohol solvent, or a solvent containing an organic solvent may be mentioned. The above-mentioned organic solvent is exemplified by one or two or more kinds of solvents exemplified as the solvent (E) of the above-mentioned photoresist composition. Among these, the organic solvent is preferably an ester solvent or a ketone solvent. The ester solvent is preferably an acetate solvent, more preferably n-butyl acetate. The ketone solvent is preferably a chain ketone, more preferably 2-heptanone.

The photoresist composition of the present invention can be used as a chemical amplification resist. In the chemically amplified resist, the acid dissociable group such as [A] polymer is dissociated by the action of an acid generated by exposure to generate a polar group represented by a carboxyl group. As a result, the solubility of the exposed portion of the resist to the alkali developing solution is increased, and the exposed portion is dissolved and removed by the alkali developing solution to obtain a positive resist pattern. Further, by using a lower polarity containing an organic solvent or the like as a developing liquid, a portion of the polar group generated by the above exposure is hardly dissolved in the developing liquid to obtain a negative resist pattern.

Since the photoresist composition is excellent in compatibility, the resist pattern obtained from the photoresist composition can be excellent in the above characteristics. Specifically, it is possible to form a resist pattern which is excellent in pattern shape and excellent in etching resistance while exhibiting MEEF performance of 4.7 or less and more preferably 4.4 or less.

Photoresist composition and resist pattern forming party according to the present invention The method and the acid generator can form a resist pattern having excellent cross-sectional shape and excellent etching resistance while exhibiting excellent MEEF performance. Accordingly, the present invention can be applied to pattern formation of lithography steps of various electronic devices such as semiconductor devices and liquid crystal devices.

[Examples]

Hereinafter, the embodiments of the present invention will be more specifically described, but the present invention is not limited by the examples.

[ ¹ H-NMR and ¹³ C-NMR]

The analysis was carried out using JNM-EX400 manufactured by JEOL Ltd. using deuterated chloroform as a measuring solvent.

[Weight average molecular weight (Mw) and number average molecular weight (Mn)]

GPC column manufactured by TOSOH (G2000HXL: 2, G3000HXL: 1 , G4000HXL: 1), at a flow rate: 1.0 ml/min, solvent: tetrahydrofuran, column temperature: 40 ° C analysis conditions, monodisperse Polystyrene was measured as a standard by gel permeation chromatography (GPC). Further, the degree of dispersion (Mw/Mn) was calculated from the measurement results of Mw and Mn.

[Content of low molecular weight component]

The content (% by mass) of the low molecular weight component is a value measured by high speed liquid chromatography (HPLC) under the following conditions.

HPLC column: Intersil ODS-25μm, 4.6mm ×250mm (made by JL Science Co., Ltd.)

Dissolution solvent: acrylonitrile / 0.1% by mass phosphoric acid aqueous solution

Flow rate: 1.0mL/min

Sample concentration: 1.0% by mass

Sample injection amount: 100 μL

Detector: differential refractometer

<Synthesis of Compounds> [Synthesis Example 1] (Synthesis of Compound (B-1))

55.0 g (230 mmol) of the compound (1) was added to dissolve 60.1 g (345 mmol) of sodium dithionite and 32.8 g of sodium hydrogencarbonate. (391 mmol) of 100 g of an acetonitrile aqueous solution (acetonitrile: water mass ratio of 4:3) was heated to 65 ° C and stirred for 7 hours. The above reaction solution was fractionated and the aqueous layer was recovered.

To the obtained aqueous layer, 100 g of acetonitrile, 19.9 g (288 mmol) of hydrogen peroxide (31.9%), 29.2 g of an aqueous solution containing hydrogen peroxide, and 7.59 g (23 mmol) of disodium tungstate were added, and the mixture was heated to 40 ° C, and stirred. hour. The above reaction solution was fractionated and the aqueous layer was recovered.

41.2 g (138 mmol) of triphenylsulfonium chloride, 120 g of dichloromethane and 60 g of water were added to the aqueous layer (solid content: 36.2 g; 138 mmol), and the mixture was stirred at room temperature for 2 hours. The reaction solution was purified by liquid separation, and the organic layer was collected and concentrated to give 62.3 g of the above compound (2).

To a solution obtained by dissolving 62.3 g (124 mmol) of the obtained compound (2) in 310 g of dichloromethane, 18.8 g (186 mmol) of triethylamine and 0.303 g (2.48 mmol) of 4-dimethylaminopyridine were added and cooled. 0 ° C. Then, 30 mL of a 37.4 g (149 mmol) dichloromethane solution of D-camphor-10-sulfonium chloride was added dropwise thereto, and the mixture was stirred for 6 hours. Subsequently, it was subjected to liquid separation purification using dichloromethane and water to obtain Compound (B-1) (yield: 79.1 g, total yield: 48%).

[Physical properties of compound (B-1)]

¹ H-NMR analysis (measurement solvent: deuterated chloroform, reference material: tetramethyl decane); δ=7.69-7.78 (m, 15H), 4.26-4.36 (m, 2H), 3.58 (d, 1H), 3.00 (d, 1H), 2.34 - 2.48 (m, 4H), 1.93 - 2.12 (m, 5H), 1.65-1.69 (m, 1H), 1.41-1.48 (m, 1H), 1.10 (s, 3H), 0.87 (s, 3H).

[Synthesis Examples 2 to 7] (Synthesis of Compounds (B-2) to (B-7))

In the same manner as in Synthesis Example 1, a compound represented by the following formula (B-2) to (B-7) was obtained.

[Physical properties of compound (B-2)]

¹ H-NMR analysis (measurement solvent: deuterated chloroform, reference material: tetramethyl decane); δ=7.69-7.78 (m, 15H), 4.26-4.36 (m, 2H), 3.01 (s, 3H), 2.43 -2.56 (m, 2H), 2.04-2.11 (m, 2H).

[Physical properties of compound (B-3)]

¹ H-NMR analysis (measurement solvent: deuterated chloroform, reference material: tetramethyl decane); δ = 7.69-7.78 (m, 15H), 4.23-4.27 (m, 2H), 3.07-3.11 (m, 2H) , 2.41-2.56 (m, 2H), 2.03-2.11 (m, 2H), 1.79-1.87 (m, 2H), 1.42-1.51 (m, 2H), 0.95 (t, 3H).

[Physical properties of compound (B-4)]

¹ H-NMR analysis (measurement solvent: deuterated chloroform, reference material: tetramethyl decane); δ=8.97 (s, 1H), 8.47 (d, 1H), 8.06 (d, 1H), 7.98 (d, 1H) ), 7.69-7.82 (m, 18H), 4.26-4.36 (m, 2H), 2.43-2.56 (m, 2H), 2.04-2.11 (m, 2H).

[Physical properties of compound (B-5)]

¹ H-NMR analysis (measurement solvent: deuterated chloroform, reference material: tetramethyl decane); δ=7.69-7.78 (m, 15H), 4.26-4.36 (m, 2H), 3.58 (d, 1H), 3.00 (d, 1H), 2.34 - 2.48 (m, 4H), 1.93 - 2.12 (m, 3H), 1.65-1.69 (m, 5H), 1.41-1.48 (m, 7H), 1.10 (s, 3H), 0.87 (s, 3H).

[Physical properties of compound (B-6)]

¹ H-NMR analysis (measurement solvent: deuterated chloroform, reference material: tetramethyl decane); δ=7.69-7.78 (m, 15H), 4.26-4.36 (m, 2H), 3.58 (d, 1H), 3.00 (d, 1H), 2.34 - 2.48 (m, 4H), 1.93 - 2.12 (m, 3H), 1.65-1.69 (m, 5H), 1.41-1.48 (m, 3H), 1.10 (s, 3H), 0.87 (s, 3H).

[Physical properties of compound (B-7)]

¹ H-NMR analysis (measurement solvent: deuterated chloroform, reference material: tetramethyl decane); δ=7.69-7.78 (m, 15H), 4.26-4.36 (m, 2H), 3.58 (d, 1H), 3.00 (d, 1H), 2.74-2.88 (m, 4H), 1.93-2.12 (m, 5H), 1.65-1.69 (m, 1H), 1.41-1.48 (m, 1H), 1.10 (s, 3H), 0.87 (s, 3H).

<[A] Synthesis of Polymers>

The compound (monomer) used in the synthesis is shown below.

[Polymerization Example 1] (Synthesis of Polymer (A-1))

Compound (M-1) 21.12 g (55 mol%), compound (M-3) 3.84 g (10 mol%), and compound (M-5) 13.44 g (35 mol%) were dissolved in 80 g of 2 In the butanone, 3.54 g of AIBN was further added to prepare a monomer solution. Next, a 200 mL three-necked flask to which 40 g of 2-butanone was fed was subjected to nitrogen blowing for 30 minutes, and then heated to 80 ° C with stirring to drip the funnel, and the prepared monomer solution was added dropwise over 3 hours. The polymerization reaction was carried out for 6 hours starting from the start of the dropwise addition as the start time of the polymerization reaction. Then, after completion of the polymerization reaction, the polymerization solution was cooled to 30 ° C or lower by water cooling. The cooled polymerization solution was poured into 800 g of methanol, and the precipitated white powder was filtered. After washing the filtered white powder twice with 160 g of methanol, The mixture was filtered and dried at 50 ° C for 17 hours to synthesize a white powdery polymer (A-1).

(A-1) had Mw of 4,500 and Mw/Mn of 1.4. The content of the low molecular weight component of (A-1) was 0.04% by mass. As a result of ¹³ C-NMR analysis, the content ratios of the structural units derived from (M-1), (M-3), and (M-5) were 54 mol%, 11 mol%, and 35 mol, respectively. %.

[Polymerization Example 2] (Synthesis of Polymer (A-2))

(A-2) was synthesized in the same manner as in Polymerization Example 1 except that the monomer of the type and the amount of use shown in the following Table 1 was used. The total mass of the monomers was the same as in Polymerization Example 1. The content, Mw and (Mw/Mn) of the low molecular weight component of each of the obtained polymers are shown in Table 1.

<[D] Synthesis of a fluorine atom-containing polymer> [Polymerization Example 3] (Synthesis of Fluorine-Containing Polymer (D-1))

14.3 g (30 mol%) of the compound (M-4) and 45.7 g (70 mol%) of the compound (M-6) were dissolved in 60 g of 2-butanone, and 3 g of AIBN was added thereto to adjust the monomer solution. The 300 mL three-necked flask to which 30 g of 2-butanone was charged was subjected to nitrogen blowing for 30 minutes, and then heated to 80 ° C while stirring the reactor, and the above monomer solution was added dropwise over 3 hours using a dropping funnel. The polymerization reaction was carried out for 6 hours starting from the start of the dropwise addition as the polymerization start time. After completion of the polymerization reaction, the polymerization solution was cooled to 30 ° C or lower by water cooling, and 600 g of a solution of methanol:water = 8:2 (mass ratio) was added to precipitate a polymer. After removing the supernatant, 120 g of methanol was added to the precipitated polymer to wash the polymer. After removing the supernatant liquid, it was dried at 50 ° C for 17 hours to synthesize a fluorine atom-containing polymer (D-1). (D-1) has Mw of 4,200 and (Mw/Mn) of 1.3. Further, as a result of ¹³ C-NMR analysis, the fluorine atom content was 5% by mass, and the content ratios of the structural units derived from (M-4) and (M-6) were 32.0 mol% and 68.0 mol%, respectively. .

<Modulation of Photoresist Composition>

The [B] acid generator, the [C] acid diffusion controller, the [E] solvent, and the [F] biasing accelerator used in the preparation of the photoresist composition are shown below.

[[B] acid generator]

[[C] Acid Diffusion Control Body]

[[E] solvent]

E-1: propylene glycol monomethyl ether acetate

E-2: alkenyl ketone

[[F] partialization accelerator]

F-1: γ-butyrolactone

[Example 1]

100 parts by mass of (A-1) of the polymer [A], 15 parts by mass of (B-1) as the acid generator (B), and (C-1) 1.1 mass of the [C] acid diffusion control body. And (7) parts by mass of (D-1) as a polymer of [D] fluorine atom, (E-1) 2,590 parts by mass of (E) solvent, and (110) parts by mass of (E-2), and as [F] The (F-1) 15 parts by mass of the partialization accelerator was filtered through a filter having a pore diameter of 0.20 μm to prepare a photoresist composition.

[Examples 2 to 14 and Comparative Examples 1 to 10]

Each of the photoresist compositions was prepared in the same manner as in Example 1 except that each of the components shown in Table 2 below and the blending amount were used.

<Formation of Resistor Patterns>

An antireflection film having a film thickness of 105 nm was formed on the surface of the 12 Å wafer using a composition for forming an antireflection film (ARC66, manufactured by Nissan Chemical Co., Ltd.). A resist film having a film thickness of 95 nm was formed on the antireflection film by using each of the photoresist compositions prepared above, and SB was performed at 115 ° C for 45 seconds. Next, an ArF excimer laser immersion exposure apparatus (NSR S610C, manufactured by NIKON) was used to expose the mask pattern by 50 nm line and 100 nm interval by NA=1.3, ratio=0.800, and Annular conditions. Resist film. After exposure, PEB was performed at 100 ° C for 45 seconds. Subsequently, development was carried out using a 2.38 mass% aqueous solution of TMAH, washed with water and dried to form a positive resist pattern of line and space. When the resist pattern is formed, a line width formed by a 1 to 1 line and a spacer mask having a target size of 50 nm is formed as a line-width of 50 nm with a line-to-space exposure amount as an optimum exposure amount. . Further, the measurement of the resist pattern was carried out using a scanning electron microscope (CG4000, manufactured by Hitachi High-Tech Co., Ltd.).

<Evaluation>

With respect to each of the photoresist compositions prepared as described above, the sensitivity, the squareness of the MEEF performance and the cross-sectional shape, and the etching resistance were evaluated by the following methods. The evaluation results are shown in Table 3.

〔Sensitivity〕

The above optimum exposure amount is taken as the sensitivity. At this time, when the sensitivity was 50 mJ/cm ² or less, the sensitivity was evaluated as "good", and when it was more than 50 mJ/cm ² , the evaluation was "poor".

[MEEF performance]

Using a scanning electron microscope (CG4000, manufactured by Hitachi High-Technology), at the above optimum exposure amount, five mask sizes (48.0 nm line/100 nm interval, 49.0 nm line/100 nm interval, 50.0 nm line/100 nm interval, 51.0) The nm line/100 nm interval, 52.0 nm line/100 nm interval) resolution, and the size of the resist pattern was measured. Using this measured value, the horizontal axis is set as the mask size, and the vertical axis is plotted as the line width formed by each mask size, and the slope of the approximate straight line is calculated by the least square method, and this slope is used as the MEEF performance. The MEEF performance is such that the closer the value is to 1, the better the display. When the MEEF performance was 4.7 or less, the evaluation was "good", and when it was more than 4.7, the evaluation was "poor".

[Rectangle of section shape]

Using the scanning electron microscope described above, the resist pattern was observed, and the line width x of the upper portion of the pattern and the line width y of the lower portion of the pattern were measured at 10 points at any point. Each ratio x/y is calculated, and the sum average of these is obtained. When the value (x/y) is in the range of 0.9 ≦ (x/y) ≦ 1.1, the squareness of the cross-sectional shape is evaluated as "good", and (x/y) is <0.9 or 1.1 < (x/y). The evaluation was "bad".

[etching resistance]

When the etching resistance can be evaluated, a generally known Western parameter is calculated for a portion surrounded by a solid line of the following formula. The value is positive and the smaller the etch The evaluation of patience is "good". The larger the value, the lower the rating.

Daxi parameter = (total number of atoms in the following section) / { (number of carbon atoms in the following section) - (number of oxygen atoms in the following section) - (number of fluorine atoms in the following section)}

The Daxi parameter of the compound of the Example, the compound (B-1) to (B-4) was 15.00, the compound (B-5) was 5.40, the compound (B-6) was 27.00, and the compound (B-7) was 6.00. Further, in the Daxi parameter system of the compound of the comparative example, the compound (CB-1) to (CB-4) was -9.00. Further, the compound (CB-5) was -2.60 after the calculation of the Western parameter for the portion of -SO ₃ ^- bonded to the anion portion. This is because the fluorine number in this part is more than the carbon number.

As understood from the results of Table 3, according to the photoresist composition of the examples, the MEEF is small, the pattern shape and the etching resistance are good, and according to the photoresist composition of the comparative example, the MEEF is large, the pattern shape and the etching resistance are good. Both are bad.

[Industrial Applicability]

According to the photoresist composition and the resist pattern forming method of the present invention, it is possible to form a resist pattern having excellent cross-sectional shape rectangularness and etching resistance while exhibiting excellent MEEF performance. The acid generator of the present invention can be preferably used as a component of the photoresist composition. Accordingly, these can be preferably used in pattern formation of lithography steps of various electronic devices such as semiconductor devices and liquid crystal devices.

Claims (7)

A photoresist composition comprising a polymer having a structural unit containing an acid dissociable group, and an acid generator containing a compound represented by the following formula (1), wherein R ¹ -SO ₂ OR ² -SO ₃ ^- Q ⁺ (1) (In the formula (1), R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 30 carbon atoms or a substituted or unsubstituted monovalent heterocyclic group having 3 to 30 ring atoms; R ² is an alkanediyl group having 1 to 30 carbon atoms or a fluorinated alkanediyl group having a fluorine number of less than 2 to 30 carbon atoms, and Q ⁺ is a monovalent photodecomposable organic cation). The photoresist composition of claim 1, wherein R ² of the above formula (1) is the fluorinated alkanediyl group, and the fluorine atom of the fluorinated alkanediyl group is 2 or more. The photoresist composition of claim 2, wherein the fluorinated alkanediyl group is represented by the following formula (i): [Chemical 2]-R ³ -CF ₂ - (i) (in the formula (i), R ³ is An alkanediyl group having 3 or more carbon atoms or a fluorinated alkanediyl group having 3 or more carbon atoms). The photoresist composition of claim 1, wherein the Q ⁺ in the above formula (1) is a group consisting of a phosphonium cation represented by the following formula (2-1) and a phosphonium cation represented by the following formula (2-2) At least one selected from the group, (In the formula (2-1), R ⁴ , R ⁵ and R ⁶ each independently represent a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or Any two or more of these groups are bonded to each other to form a ring structure together with the sulfur atom to which they are bonded. In the formula (2-2), R ⁷ and R ⁸ each independently represent a substituted or unsubstituted carbon. An alkyl group of 1 to 20 or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a ring structure in which these groups are bonded to each other and to the iodine atom to which they are bonded. The photoresist composition of claim 1, wherein the structural unit is represented by the following formula (3), (In the formula (3), R ⁹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, R ¹⁰ is a chain hydrocarbon group having 1 to 10 carbon atoms, and R ¹¹ and R ¹² each independently represent a carbon number of 1 to a chain hydrocarbon group of 10 or an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or an alicyclic structure having 3 to 20 ring carbon atoms bonded together with the carbon atoms bonded thereto. A resist pattern forming method having the steps of: forming a resist film, exposing the resist film, and exposing the exposed resist film, and by requesting item 1 The photoresist composition forms the above resist film. An acid generator comprising a compound represented by the following formula (1): R ⁵ -SO ₂ OR ² -SO ₃ ^- Q ⁺ (1) (in the formula (1), R ¹ is a substitution or An unsubstituted monovalent hydrocarbon group having 1 to 30 carbon atoms or a substituted or unsubstituted monovalent heterocyclic group having 3 to 30 ring atoms, and R ² is an alkanediyl group having 1 to 30 carbon atoms or a fluorine number smaller than a carbon number A fluorinated alkanediyl group having 2 to 30 carbon atoms, and Q ⁺ is a monovalent photodecomposable organic cation).