JP5086907B2 - Resist processing method - Google Patents

Description

  The present invention relates to a resist processing method, and more particularly to a resist processing method used for forming a fine resist pattern by a double patterning method and a double imaging method.

  In recent years, there has been an increasing demand for miniaturization of semiconductor microfabrication using lithography technology, and as a process for realizing a resist pattern line width of 32 nm or less, a double patterning method (for example, Patent Document 1) or double imaging is used. Laws (for example, Non-Patent Document 1) have been proposed. Here, the double patterning method is a space twice as large as the target resist pattern, and after performing the first transfer by performing normal exposure, development and etching steps, the same exposure is again performed between the spaces. This is a technique for obtaining a desired fine resist pattern by performing a second transfer by performing development and etching processes. The double imaging method is a space twice as large as the target resist pattern. After performing normal exposure, development, and processes, the resist pattern is processed with a chemical called a freezing agent. This is a technique for obtaining a desired fine resist pattern by performing similar exposure and development again.

JP 2007-31508 A Proceedings of SPIE. Vol. 6520, 65202F (2007)

  An object of the present invention is to provide a resist processing method capable of realizing a double patterning method and a double imaging method.

The resist processing method of the present invention includes (1) a resin (A) having an acid labile group, insoluble or hardly soluble in an alkaline aqueous solution, and soluble in an alkaline aqueous solution by acting with an acid, photoacid generation A first resist composition containing an agent (B) and a crosslinking agent (C) and having a weight average molecular weight of the resin (A) of 10,000 or more and 40000 or less is coated on a substrate and dried to give a first Obtaining a resist film;
(2) a step of pre-baking the first resist film;
(3) a step of exposing the first resist film;
(4) a step of post-exposure baking the first resist film;
(5) a step of developing with a first alkaline developer to obtain a first resist pattern;
(6) a step of hard baking the first resist pattern;
(7) A step of applying a second resist composition on the first resist pattern and drying to obtain a second resist film;
(8) a step of pre-baking the second resist film;
(9) a step of exposing the second resist film;
(10) a step of post-exposure baking the second resist film; and
(11) A step of developing with a second alkaline developer to obtain a second resist pattern,
It is characterized by including.

（式中、Ｒ^aは炭素数１〜６の直鎖または分岐の炭化水素基、あるいは炭素数３〜３０の環式炭化水素基を表し、Ｒ^aが環式炭化水素基である場合は、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数１〜４のペルフルオロアルキル基、エーテル基、エステル基、ヒドロキシ基又はシアノ基の１以上が置換されていてもよい。Ａ⁺は有機対イオンを表す。Ｙ¹、Ｙ²は、それぞれ独立に、フッ素原子または炭素数１〜６のペルフルオロアルキル基を表す。） In such a treatment method, the crosslinking agent (C) is preferably at least one selected from the group consisting of a urea crosslinking agent, an alkylene urea crosslinking agent, and a glycoluril crosslinking agent.
Moreover, it is preferable that content of a crosslinking agent (C) is 0.5-30 mass parts with respect to 100 mass parts of resin.
Further, the acid-labile group of the resin (A) is preferably a group having an alkyl ester or lactone ring in which the α-position of the ether bond is a quaternary carbon atom, or a group having a carboxylic acid ester.
The photoacid generator (B) is preferably a compound represented by the formula (I).

(In the formula, R ^a represents a linear or branched hydrocarbon group having 1 to 6 carbon atoms, or a cyclic hydrocarbon group having 3 to 30 carbon atoms, and when R ^a is a cyclic hydrocarbon group, One or more of an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a perfluoroalkyl group having 1 to 4 carbon atoms, an ether group, an ester group, a hydroxy group, or a cyano group may be substituted. A ⁺ represents an organic counter ion, and Y ¹ and Y ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.)

（式中、Ｙ¹、Ｙ²は、それぞれ独立して、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表し、Ｘは−ＯＨ又は−Ｙ−ＯＨを表し（ここで、Ｙは、炭素数１〜６の直鎖又は分岐アルキレン基である）、ｎは１〜９の整数を表し、Ａ⁺は有機対イオンを表す。） Furthermore, the photoacid generator (B) is preferably a compound represented by the formula (III).

(Wherein Y ¹ and Y ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group, X represents —OH or —Y—OH (where Y represents carbon N represents an integer of 1 to 9, and A ⁺ represents an organic counter ion.)

（式中、Ｐ¹〜Ｐ⁵、Ｐ¹⁰〜Ｐ²¹は、それぞれ独立して、水素原子、水酸基、炭素数１〜１２のアルキル基又は炭素数１〜１２のアルコキシ基を表す。Ｐ⁶、Ｐ⁷は、それぞれ独立して、炭素数１〜１２のアルキル基、炭素数３〜１２のシクロアルキル基であるか、Ｐ⁶とＰ⁷とが結合して、炭素数３〜１２の２価の炭化水素基を表す。Ｐ⁸は水素原子を表し、Ｐ⁹は炭素数１〜１２のアルキル基、炭素数３〜１２のシクロアルキル基又は置換されていてもよい芳香族基を表すか、Ｐ⁸とＰ⁹とが結合して、炭素数３〜１２の２価の炭化水素基を表す。Ｄは、硫黄原子又は酸素原子を表す。ｍは、０又は１、ｒは１〜３の整数を表す。）
さらに、樹脂（Ａ）の重量平均分子量が１２０００以上、４００００以下であることが好ましい。 In particular, the photoacid generator (B) is a compound containing one or more cations selected from the group consisting of formulas (IIa), (IIb), (IIc), (IId) and (IV). preferable.

(.P ^{6 wherein, P 1 ~P 5, P 10} ~P 21 is representing independently a hydrogen atom, a hydroxyl group, an alkyl group or an alkoxy group having 1 to 12 carbon atoms having 1 to 12 carbon atoms, P ⁷ is independently an alkyl group having 1 to 12 carbon atoms and a cycloalkyl group having 3 to 12 carbon atoms, or P ⁶ and P ⁷ are bonded to form a divalent valence having 3 to 12 carbon atoms. P ⁸ represents a hydrogen atom, and P ⁹ represents an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an optionally substituted aromatic group, P ⁸ and P ⁹ are combined to represent a divalent hydrocarbon group having 3 to 12 carbon atoms, D represents a sulfur atom or an oxygen atom, m is 0 or 1, and r is 1 to 3. Represents an integer.)
Furthermore, it is preferable that the weight average molecular weights of resin (A) are 12000 or more and 40000 or less.

  According to the resist processing method of the present invention, the double patterning method and the double imaging method are realized, that is, the first layer resist pattern is formed in a desired shape with more certainty and accuracy, and the second layer and thereafter. Even with this process, the shape of the resist pattern of the first layer is maintained without being deformed, and as a result, a very fine pattern can be formed.

  The resist composition used in the resist processing method of the present invention mainly comprises a resin (A), a photoacid generator (B) and a crosslinking agent (C). C) is contained.

  The resin in the resist composition of the present invention has an acid-labile group, is insoluble or hardly soluble in an alkaline aqueous solution before exposure, and an acid generated from the photoacid generator (B) by exposure is The acid-labile groups in the resin can be cleaved by acting catalytically and dissolved in an aqueous alkali solution, while the unexposed portions in the resin remain alkali-insoluble. Thus, a positive resist pattern can be formed by developing the resist composition later with an alkaline aqueous solution. Here, insoluble or hardly soluble in an alkaline aqueous solution may vary depending on the type and concentration of the alkaline aqueous solution, but generally, an alkali generally used as a developer for dissolving 1 g or 1 ml of the resist composition. The term “solubility” means that the aqueous solution needs about 100 ml or more, and “dissolving” means the solubility that the above alkaline aqueous solution is less than 100 ml in order to dissolve 1 g or 1 ml of the resist composition.

The acid-labile group in the resin (A) used in the present invention means a group that is cleaved or easily cleaved by an acid generated from the photoacid generator (B) described later, as described above, The group is not particularly limited as long as it is a group having such properties.
For example, a group having an alkyl ester in which the α position of the ether bond is a quaternary carbon atom, a group having a lactone ring in which the α position of the ether bond is a quaternary carbon atom, a carboxylic acid such as an acetal type ester and an alicyclic ester Examples include groups having an ester. Especially, what gives a carboxyl group by the effect | action of the acid generate | occur | produced from the photo-acid generator (B) mentioned later is preferable. Here, the quaternary carbon atom means a carbon atom that is bonded to a substituent other than a hydrogen atom and is not bonded to hydrogen. In particular, the acid-labile group is preferably a quaternary carbon atom in which the α-position carbon atom of the ether bond is bonded to three carbon atoms.

When a group having a carboxylic acid ester which is one of acid labile groups is exemplified as “R ester of —COOR”, it is represented by tert-butyl ester (that is, —COO—C (CH ₃ ) ₃ ). An alkyl ester in which the α-position of the ether bond is a quaternary carbon atom;
Methoxymethyl ester, ethoxymethyl ester, 1-ethoxyethyl ester, 1-isobutoxyethyl ester, 1-isopropoxyethyl ester, 1-ethoxypropyl ester, 1- (2-methoxyethoxy) ethyl ester, 1- (2- Acetoxyethoxy) ethyl ester, 1- [2- (1-adamantyloxy) ethoxy] ethyl ester, 1- [2- (1-adamantanecarbonyloxy) ethoxy] ethyl ester, tetrahydro-2-furyl ester and tetrahydro-2- Acetal type or lactone ring-containing ester such as pyranyl ester;
An alicyclic ring in which the α-position of the ether bond is a quaternary carbon atom, such as isobornyl ester, 1-alkyl cycloalkyl ester, 2-alkyl-2-adamantyl ester, 1- (1-adamantyl) -1-alkylalkyl ester Formula ester etc. are mentioned.

  Examples of the group having a carboxylic acid ester include a group having a (meth) acrylic acid ester, a norbornene carboxylic acid ester, a tricyclodecene carboxylic acid ester, and a tetracyclodecene carboxylic acid ester.

This resin (A) can be produced by addition polymerization of a monomer having an acid labile group and an olefinic double bond.
As the monomer used here, a monomer containing a bulky group such as an alicyclic structure, particularly a bridged structure as an acid labile group (for example, a 2-alkyl-2-adamantyl group, 1- (1- Adamantyl) -1-alkylalkyl groups, etc.) are preferred because the resolution of the resulting resist tends to be excellent. Examples of the monomer containing a bulky group include 2-alkyl-2-adamantyl (meth) acrylate, 1- (1-adamantyl) -1-alkylalkyl (meth) acrylate, and 5-norbornene-2-carboxylic acid. Examples include 2-alkyl-2-adamantyl, 1- (1-adamantyl) -1-alkylalkyl 5-norbornene-2-carboxylate, and the like.

In particular, when 2-alkyl-2-adamantyl (meth) acrylate is used as a monomer, it is preferable because the resolution of the resulting resist tends to be excellent.
Examples of (meth) acrylic acid 2-alkyl-2-adamantyl include 2-methyl-2-adamantyl acrylate, 2-methyl-2-adamantyl methacrylate, 2-ethyl-2-adamantyl acrylate, and methacrylic acid 2 -Ethyl-2-adamantyl, 2-isopropyl-2-adamantyl acrylate, 2-isopropyl-2-adamantyl methacrylate, 2-n-butyl-2-adamantyl acrylate and the like.
Among these, when 2-ethyl-2-adamantyl (meth) acrylate or 2-isopropyl-2-adamantyl (meth) acrylate is used, the resulting resist tends to have excellent sensitivity and heat resistance. preferable.

  (Meth) acrylic acid 2-alkyl-2-adamantyl can be usually produced by a reaction of 2-alkyl-2-adamantanol or a metal salt thereof with acrylic acid halide or methacrylic acid halide.

  One feature of the resin (A) used in the present invention is that it contains a structural unit having a highly polar substituent. As such a structural unit, for example, a structural unit derived from a compound in which one or more hydroxyl groups are bonded to 2-norbornene, a structural unit derived from (meth) acrylonitrile, an α-position of an ether group is a secondary carbon atom or Tertiary carbon atom alkyl ester, structural unit derived from (meth) acrylic acid ester which is 1-adamantyl ester bonded with one or more hydroxyl groups, derived from styrene monomer such as p- or m-hydroxystyrene And structural units derived from (meth) acryloxy-γ-butyrolactone in which the lactone ring may be substituted with an alkyl group. 1-adamantyl ester is an acid-stable group although the α position of the ether bond is a quaternary carbon atom.

  Specifically, monomers having a highly polar substituent include 3-hydroxy-1-adamantyl (meth) acrylate, 3,5-dihydroxy-1-adamantyl (meth) acrylate, α- (meth) acryloxy- Examples thereof include γ-butyrolactone, β- (meth) acryloxy-γ-butyrolactone, a monomer represented by the following formula (a), a monomer represented by (b), and hydroxystyrene.

（式中、Ｒ¹及びＲ²は、それぞれ独立して、水素原子又はメチル基を表し、Ｒ³及びＲ⁴は、それぞれ独立して、水素原子、メチル基又はトリフルオロメチル基又はハロゲン原子を表し、ｐ及びｑは、１〜３の整数を表す。ｐが２又は３のときには、Ｒ³は互いに異なる基であってもよく、ｑが２又は３のときには、Ｒ⁴は互いに異なる基であってもよい。）

(In the formula, R ¹ and R ² each independently represent a hydrogen atom or a methyl group, and R ³ and R ⁴ each independently represent a hydrogen atom, a methyl group, a trifluoromethyl group, or a halogen atom. And p and q represent an integer of 1 to 3. When p is 2 or 3, R ³ may be a different group, and when q is 2 or 3, R ⁴ is a different group. May be.)

  Among them, a structural unit derived from 3-hydroxy-1-adamantyl (meth) acrylate, a structural unit derived from 3,5-dihydroxy-1-adamantyl (meth) acrylate, α- (meth) acryloxy-γ- A structural unit derived from butyrolactone, a structural unit derived from β- (meth) acryloxy-γ-butyrolactone, a structure derived from the monomer represented by formula (a), and a structural unit derived from the monomer represented by formula (b) A resist obtained from the resin containing the resin is preferable because the adhesion to the substrate and the resolution of the resist tend to be improved.

  The resin (A) used in the present invention may contain other structural units. For example, a structural unit derived from a monomer having a free carboxylic acid group such as acrylic acid or methacrylic acid, a structural unit derived from an aliphatic unsaturated dicarboxylic acid anhydride such as maleic anhydride or itaconic anhydride, 2-norbornene Examples include structural units derived, structural units derived from (meth) acrylic acid esters in which the α-position of the ether group is a secondary or tertiary carbon atom alkyl ester or 1-adamantyl ester. 1-adamantyl ester is an acid-stable group although the α position of the ether bond is a quaternary carbon atom.

  Monomers such as 3-hydroxy-1-adamantyl (meth) acrylate and 3,5-dihydroxy-1-adamantyl (meth) acrylate are commercially available. For example, the corresponding hydroxyadamantane may be (meth) acrylic acid or It can also be produced by reacting with the halide.

  Monomers such as (meth) acryloyloxy-γ-butyrolactone are obtained by reacting α- or β-bromo-γ-butyrolactone, which may have a lactone ring substituted with an alkyl group, with acrylic acid or methacrylic acid, or having a lactone ring It can be produced by reacting an α- or β-hydroxy-γ-butyrolactone optionally substituted with an alkyl group with an acrylic acid halide or a methacrylic acid halide.

Examples of the monomer that gives the structural unit represented by the formulas (a) and (b) include (meth) acrylic acid esters of alicyclic lactones having the following hydroxyl groups, and mixtures thereof. These esters can be produced, for example, by a reaction between a corresponding alicyclic lactone having a hydroxyl group and (meth) acrylic acid (see, for example, JP-A No. 2000-26446).

  Here, as (meth) acryloyloxy-γ-butyrolactone, for example, α-acryloyloxy-γ-butyrolactone, α-methacryloyloxy-γ-butyrolactone, α-acryloyloxy-β, β-dimethyl-γ-butyrolactone, α- Methacryloyloxy-β, β-dimethyl-γ-butyrolactone, α-acryloyloxy-α-methyl-γ-butyrolactone, α-methacryloyloxy-α-methyl-γ-butyrolactone, β-acryloyloxy-γ-butyrolactone, β- Examples include methacryloyloxy-γ-butyrolactone, β-methacryloyloxy-α-methyl-γ-butyrolactone, and the like.

  In the case of KrF excimer laser exposure, sufficient transmittance can be obtained even if a structural unit derived from a styrene monomer such as p- or m-hydroxystyrene is used as the structural unit of the resin. Such a copolymer resin can be obtained by radical polymerization of the corresponding (meth) acrylic acid ester monomer, acetoxystyrene, and styrene, followed by deacetylation with an acid.

（式（ｃ）中、Ｒ⁵及び／又はＲ⁶は、それぞれ独立して、水素原子、炭素数１〜３のアルキル基、カルボキシル基、シアノ基もしくは−ＣＯＯＵ（Ｕはアルコール残基である）を表すか、あるいは、Ｒ⁵及びＲ⁶が結合して、−Ｃ（＝Ｏ）ＯＣ（＝Ｏ）−で示されるカルボン酸無水物残基を表す。） Moreover, since the resin containing a structural unit derived from 2-norbornene has an alicyclic skeleton directly in the main chain, it has a sturdy structure and exhibits excellent dry etching resistance. The structural unit derived from 2-norbornene is introduced into the main chain by radical polymerization using, for example, an aliphatic unsaturated dicarboxylic anhydride such as maleic anhydride or itaconic anhydride in addition to the corresponding 2-norbornene. Can do. Therefore, the one formed by opening the double bond of the norbornene structure can be represented by the formula (c), and the one formed by opening the double bond of maleic anhydride and itaconic anhydride, These can be represented by formulas (d) and (e), respectively.

(In formula (c), R ⁵ and / or R ⁶ are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a carboxyl group, a cyano group, or —COOU (U is an alcohol residue). Or R ⁵ and R ⁶ are bonded to each other to represent a carboxylic acid anhydride residue represented by —C (═O) OC (═O) —.)

When R ⁵ and / or R ⁶ is —COOU, the carboxyl group is an ester, and the alcohol residue corresponding to U has, for example, about 1 to 8 carbon atoms that may be substituted. An alkyl group, a 2-oxooxolan-3- or -4-yl group, and the like. Here, the alkyl group may be substituted with a hydroxyl group, an alicyclic hydrocarbon group or the like.

Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, octyl group, 2-ethylhexyl group and the like. It is done.
Examples of the alkyl group to which a hydroxyl group is bonded, that is, a hydroxylalkyl group, include a hydroxymethyl group and a 2-hydroxyethyl group.
Examples of the alicyclic hydrocarbon group include those having about 3 to 30 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclodecyl, cyclohexenyl, bicyclobutyl, bicyclohexyl, bicyclooctyl, 2 -Norbornyl and the like.
In the present specification, any chemical formula varies depending on the number of carbon atoms, but unless otherwise specified, the above-described groups such as an alkyl group are exemplified as described above. Moreover, the group which can take both a straight chain | strand or a branch includes both (it is the same below).

As described above, specific examples of the norbornene structure represented by the formula (c), which is a monomer that gives a stable structural unit to an acid, include the following compounds.
2-norbornene,
2-hydroxy-5-norbornene,
5-norbornene-2-carboxylic acid,
Methyl 5-norbornene-2-carboxylate,
2-hydroxy-1-ethyl 5-norbornene-2-carboxylate,
5-norbornene-2-methanol,
5-norbornene-2,3-dicarboxylic anhydride.

In addition, if U of —COOU of R ⁵ and / or R ^{6 in} the formula (c) is an acid labile group such as an alicyclic ester in which the α position of the ether bond is a quaternary carbon atom, Although it has a norbornene structure, it is a structural unit having an acid labile group.
Examples of the monomer containing a norbornene structure and an acid labile group include, for example, 5-norbornene-2-carboxylic acid-t-butyl, 5-norbornene-2-carboxylic acid 1-cyclohexyl-1-methylethyl, 5- 1-methylcyclohexyl norbornene-2-carboxylate, 2-methyl-2-adamantyl 5-norbornene-2-carboxylate, 2-ethyl-2-adamantyl 5-norbornene-2-carboxylate, 5-norbornene-2-carboxyl Acid 1- (4-methylcyclohexyl) -1-methylethyl, 5-norbornene-2-carboxylic acid 1- (4-hydroxycyclohexyl) -1-methylethyl, 5-norbornene-2-carboxylic acid 1-methyl-1 -(4-oxocyclohexyl) ethyl, 5-norbornene-2-carboxylic acid 1- (1-adap Pentyl) -1-methylethyl, and the like.

The resin (A) of the resist composition used in the present invention usually varies depending on the type of radiation for patterning exposure, the type of acid-labile group, etc., but usually a monomer having an acid-labile group in the resin It is preferable to adjust the content of the structural unit derived from to a range of 10 to 80 mol%.
And as a structural unit derived from a monomer having an acid-labile group, in particular, 2-alkyl-2-adamantyl (meth) acrylate, 1- (1-adamantyl) -1-alkylalkyl (meth) acrylate When the structural unit is derived from the above, the structural unit is made to be 15 mol% or more of the total structural units constituting the resin, so that the resin has an alicyclic group, so that the resin has a strong structure, and the resist is dried. This is advantageous in terms of etching resistance.

In addition, when using an alicyclic compound having an olefinic double bond in the molecule and an aliphatic unsaturated dicarboxylic acid anhydride as monomers, these tend to be difficult to undergo addition polymerization. These are preferably used in excess.
Further, as the monomer used, monomers having the same olefinic double bond but different acid labile groups may be used in combination, or monomers having the same acid labile group but different olefinic double bonds may be used. You may use together, and you may use together the monomer from which the combination of an acid labile group and an olefinic double bond differs.

The resin (A) suitably has a weight average molecular weight of 10,000 or more, and more preferably 10500 or more, 11000 or more, 11500 or more, 12000 or more. Further, the upper limit is not particularly limited, but if the weight average molecular weight is too large, lithography performance is broken and defects are likely to occur. Therefore, 40000 or less is suitable, and 39000 or less, 38000 or less, and 37000 or less are preferable.
The weight average molecular weight in this case can be determined by gel permeation chromatography, as will be described later.
In the resin (A) in the present invention, for example, a predetermined correlation between the weight average molecular weight and the glass transition temperature (Tg) has been confirmed. In particular, when the weight average molecular weight decreases, the change in Tg is asymptotic. Has been found to have Accordingly, in the present invention, from another viewpoint, the resin (A) having a Tg of 148 ° C. or higher is suitable, and those having a Tg of 149 ° C. or higher and 150 ° C. or higher are preferable. Furthermore, the thing of 160 degrees C or less is suitable, and also the thing of 159 degrees C or less is preferable.

（式中、Ｒ^aは炭素数１〜６の直鎖または分岐の炭化水素基、あるいは炭素数３〜３０の環式炭化水素基を表し、Ｒ^aが環式炭化水素基である場合は、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数１〜４のペルフルオロアルキル基、エーテル基、エステル基、ヒドロキシ基又はシアノ基の１以上が置換されていてもよい。Ａ⁺は有機対イオンを表す。Ｙ¹、Ｙ²は、それぞれ独立に、フッ素原子または炭素数１〜６のペルフルオロアルキル基を表す。） The photoacid generator (B) in the resist composition used in the present invention is not particularly limited as long as it can generate an acid upon exposure, and those known in the art can be used.
For example, the photoacid generator (B) includes a compound represented by the formula (I).

(In the formula, R ^a represents a linear or branched hydrocarbon group having 1 to 6 carbon atoms, or a cyclic hydrocarbon group having 3 to 30 carbon atoms, and when R ^a is a cyclic hydrocarbon group, One or more of an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a perfluoroalkyl group having 1 to 4 carbon atoms, an ether group, an ester group, a hydroxy group, or a cyano group may be substituted. A ⁺ represents an organic counter ion, and Y ¹ and Y ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.)

Here, the hydrocarbon may be the same as the alkyl group described above, or one having one or more double bonds or triple bonds introduced at any position of the alkyl group. Of these, an alkyl group is preferable.
The cyclic hydrocarbon group having 3 to 30 carbon atoms may or may not be an aromatic group, and examples thereof include a monocyclic or bicyclic hydrocarbon group, an aryl group, and an aralkyl group. It is done. Specific examples include phenyl, indenyl, naphthyl, adamantyl, norbornenyl, tolyl, benzyl and the like in addition to the above-described alicyclic hydrocarbon groups such as cycloalkyl and norbornyl having 4 to 8 carbon atoms.
Examples of the alkoxy group include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, tert-butoxy, pentoxy, hexoxy, octyloxy, 2-ethylhexyloxy group and the like.
Examples of perfluoroalkyl include trifluoromethyl, perfluoroethyl, perfluoropropyl, perfluorobutyl and the like.

（式（Ｖ）および式（ＶＩ）中、環Ｅは炭素数３〜３０の環式炭化水素基を表し、環Ｅは炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数１〜４のペルフルオロアルキル基、炭素数１〜６のヒドロキシアルキル基、水酸基又はシアノ基で置換基されていてもよい。Ｚ’は単結合又は炭素数１〜４のアルキレン基を表す。Ａ⁺、Ｙ¹、Ｙ²は上記と同義である。）
アルキレン基としては、以下に示す（Ｙ−１）〜（Ｙ−１２）が例示される。 The photoacid generator (B) may be, for example, a compound represented by the following formula (V) or formula (VI).

(In Formula (V) and Formula (VI), Ring E represents a cyclic hydrocarbon group having 3 to 30 carbon atoms, Ring E is an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, It may be substituted with a C1-C4 perfluoroalkyl group, a C1-C6 hydroxyalkyl group, a hydroxyl group or a cyano group, Z 'represents a single bond or a C1-C4 alkylene group. A ⁺ , Y ¹ and Y ² are as defined above.)
Examples of the alkylene group include (Y-1) to (Y-12) shown below.

［式中、Ｙ¹、Ｙ²は、それぞれ独立して、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表し、Ｘは−ＯＨ又は−Ｙ−ＯＨを表し（ここで、Ｙは、炭素数１〜６の直鎖又は分岐アルキレン基である）、ｎは１〜９の整数を表し、Ａ⁺は上記と同義である。］ Further, the photoacid generator (B) may be a compound represented by the following formula (III).

[Wherein Y ¹ and Y ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group, X represents —OH or —Y—OH (where Y represents carbon N represents an integer of 1 to 9, and A ⁺ has the same meaning as described above. ]

As Y ¹ and Y ² , a fluorine atom is particularly preferable.
Moreover, as n, 1-2 are preferable.
Examples of Y include the following (Y-1) to (Y-12), and among them, (Y-1) and (Y-2) are preferable because of easy production.

式（Ｉ）、（III）、（Ｖ）又は（ＶＩ）で表される化合物におけるアニオンとしては、例えば、以下の化合物が挙げられる。

Examples of the anion in the compound represented by the formula (I), (III), (V) or (VI) include the following compounds.

In addition, the photoacid generator may be a compound represented by the following formula (VII).
_{^{A + - O 3 S-R}} b (VII)
(In the formula, R ^b represents a linear or branched alkyl group or perfluoroalkyl group having 1 to 6 carbon atoms, and A ⁺ has the same meaning as described above.)
R ^b is particularly preferably a C 1-6 perfluoroalkyl group.
Specific examples of the anion of the formula (VII) include ions such as trifluoromethanesulfonate, pentafluoroethanesulfonate, heptafluoropropanesulfonate, and perfluorobutanesulfonate.

（式（VIII）中、Ｐ^a〜Ｐ^cは、それぞれ独立して、直鎖又は分岐の炭素数１〜３０のアルキル基又は炭素数３〜３０の環式炭化水素基を表す。Ｐ^a〜Ｐ^cがアルキル基である場合には、水酸基、炭素数１〜１２のアルコキシ基、炭素数３〜１２の環式炭化水素基、エーテル基、エステル基、カルボニル基、シアノ基、アミノ基、炭素数１〜４のアルキル基置換アミノ基、アミド基の１以上を置換基として含んでいてもよく、Ｐ^a〜Ｐ^cが環式炭化水素基である場合には、水酸基、炭素数１〜１２のアルキル基又は炭素数１〜１２のアルコキシ基、エーテル基、エステル基、カルボニル基、シアノ基、アミノ基、炭素数１〜４のアルキル基置換アミノ基、アミド基の一つ以上を置換基として含んでいてもよい。） In the compounds represented by the formulas (I), (III) and (V) to (VII), the organic counter ion of A ⁺ includes a cation represented by the formula (VIII).

(In Formula (VIII), P ^{a to} P ^c each independently represents a linear or branched alkyl group having 1 to 30 carbon atoms or a cyclic hydrocarbon group having 3 to 30 carbon atoms. P ^a to When P ^c is an alkyl group, a hydroxyl group, an alkoxy group having 1 to 12 carbon atoms, a cyclic hydrocarbon group having 3 to 12 carbon atoms, an ether group, an ester group, a carbonyl group, a cyano group, an amino group, carbon 1 to 4 alkyl group-substituted amino groups and one or more of amide groups may be included as substituents, and when P ^{a to} P ^c are cyclic hydrocarbon groups, a hydroxyl group or a carbon number of 1 to 12 Or an alkyl group having 1 to 12 carbon atoms, an ether group, an ester group, a carbonyl group, a cyano group, an amino group, an alkyl group having 1 to 4 carbon atoms, a substituted amino group, or an amide group as a substituent. May be included.)

式（IIａ）中、Ｐ¹〜Ｐ³は、それぞれ独立して、水素原子、水酸基、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、エーテル基、エステル基、カルボニル基、シアノ基、炭素数１〜４のアルキル基が置換していてもよいアミノ基、アミド基を表す。
アルキル基及びアルコキシ基としては、上記と同様のものが挙げられる。 In particular, the cations represented by the following formula (IIa), formula (IIb), formula (IIc) and formula (IId) are exemplified.

In formula (IIa), P ^{1 to} P ³ are each independently a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an ether group, an ester group, a carbonyl group, A cyano group, an amino group that may be substituted by an alkyl group having 1 to 4 carbon atoms, or an amide group is represented.
Examples of the alkyl group and alkoxy group include the same groups as described above.

式（IIｅ）中、Ｐ²²〜Ｐ²⁴は、それぞれ独立して、水素原子、炭素数１〜４のアルキル基を表し、アルキル基は、直鎖でも分岐していてもよい。 Among the cations represented by the formula (IIa), the cation represented by the formula (IIe) is preferable because of easy production.

In formula (IIe), P ^{22 to} P ²⁴ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and the alkyl group may be linear or branched.

式（IIｂ）中、Ｐ⁴、Ｐ⁵は、それぞれ独立して、水素原子、水酸基、炭素数１〜１２のアルキル基又は炭素数１〜１２のアルコキシ基を表す。 Further, the organic counter ion of A ⁺ may be a cation represented by the formula (IIb) containing an iodine cation.

In formula (IIb), P ⁴ and P ⁵ each independently represent a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.

Further, the organic counter ion of A ⁺ may be a cation represented by the formula (IIc).

In formula (IIc), P ⁶ and P ⁷ each independently represent an alkyl group having 1 to 12 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms, and this alkyl group is branched even in a straight chain. May be.
Examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclodecyl group.
Further, by bonding P ⁶ and P ^7, it may be a divalent hydrocarbon group having 3 to 12 carbon atoms. The carbon atom contained in the divalent hydrocarbon group may be optionally substituted with a carbonyl group, an oxygen atom, or a sulfur atom.
The divalent hydrocarbon group may be any of saturated, unsaturated, chained, and cyclic hydrocarbons. Among them, a chain saturated hydrocarbon group, particularly an alkylene group is preferable. Examples of the alkylene group include trimethylene, tetramethylene, pentamethylene, hexamethylene and the like.

P ⁸ represents a hydrogen atom, and P ⁹ represents an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an optionally substituted aromatic group, or P ⁸ and P ⁹ Are combined to represent a divalent hydrocarbon group having 3 to 12 carbon atoms.
Examples of the alkyl group, cycloalkyl group, and divalent hydrocarbon group are the same as those described above.
As the aromatic group, those having 6 to 20 carbon atoms are preferable, for example, aryl groups and aralkyl groups are preferable, and specific examples include phenyl, tolyl, xylyl, biphenyl, naphthyl, benzyl, phenethyl, anthracenyl groups and the like. It is done. Of these, a phenyl group and a benzyl group are preferable. Examples of the group that may be substituted with an aromatic group include a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, and a hydroxyalkyl group having 1 to 6 carbon atoms.

Further, the organic counter ion of A ⁺ may be a cation represented by the formula (IId).

In formula (IId), P ^{10 to} P ²¹ each independently represents a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. This alkyl group and alkoxy group are as defined above. D represents a sulfur atom or an oxygen atom. m represents 0 or 1.

Specific examples of the cation A ^{+ represented by} the formula (IIa) include cations represented by the following formula.

Specific examples of the cation A ^{+ represented by} the formula (IIb) include cations represented by the following formula.

Specific examples of the cation A ^{+ represented by} the formula (IIc) include cations represented by the following formula.

Specific examples of the cation A ^{+ represented by} the formula (IId) include cations represented by the following formula.

（式中、ｒは１〜３の整数である。）
式（ＩＶ）中、ｒは、特に、１〜２であることが好ましく、２であることが最も好ましい。
水酸基の結合位置は、特に限定されないが、容易に入手可能で低価格であることから、４位の位置であることが好ましい。 In the compounds represented by formulas (I), (III), (V) to (VII), A ⁺ may be a cation represented by formula (IV).

(Wherein, r is an integer of 1 to 3)
In formula (IV), r is particularly preferably 1 to 2, and most preferably 2.
The bonding position of the hydroxyl group is not particularly limited, but the 4-position is preferable because it is readily available and inexpensive.

Specific examples of the cation represented by the formula (IV) include those represented by the following formula.

（式中、Ｐ^６〜Ｐ^９及びＰ²²〜Ｐ²⁴、Ｙ¹、Ｙ²は上記と同義、Ｐ²⁵〜Ｐ²⁷は、互いに独立に、水素原子、炭素数１〜４のアルキル基を表す。） In particular, as the compounds represented by the formula (I) or (III) of the present invention, those represented by the formulas (IXa) to (IXe) give a chemically amplified resist composition exhibiting excellent resolution and pattern shape. Since it becomes a photo-acid generator, it is preferable.

^(Wherein, P 6 to P ⁹ and ^{P 22 ~P 24, Y 1,} Y 2 are as defined above, P ²⁵ to P ²⁷ independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms .)

Among these, the following compounds are preferably used because they are easy to produce.

  Compounds of the formulas (I), (III), (V) to (VII) can be produced by, for example, the method described in JP-A-2006-257078 and a method analogous thereto.

（式中、Ｚ’及びＥは上記と同義、Ｍは、Ｌｉ、Ｎａ、Ｋ又はＡｇを表す。）
式（３）で表されるオニウム塩とを、
Ａ^＋ Ｚ⁻ （３）
（式中、Ａ⁺は、上記と同義、ＺはＦ、Ｃｌ、Ｂｒ、Ｉ、ＢＦ₄、ＡｓＦ₆、ＳｂＦ₆、ＰＦ₆、又はＣｌＯ₄を表す。）
それぞれ、例えば、アセトニトリル、水、メタノール等の不活性溶媒中にて、０℃〜１５０℃程度の温度範囲、好ましくは０℃〜１００℃程度の温度範囲にて攪拌して反応させる方法等が挙げられる。 In particular, the production method of formula (V) or formula (VI) includes, for example, a salt represented by formula (1) or formula (2),

(In the formula, Z ′ and E are as defined above, and M represents Li, Na, K or Ag.)
An onium salt represented by the formula (3),
A ⁺ Z ^- (3)
(In the formula, A ⁺ is as defined above, and Z represents F, Cl, Br, I, BF ₄ , AsF ₆ , SbF ₆ , PF ₆ , or ClO _4. )
Examples thereof include a method of stirring and reacting in an inert solvent such as acetonitrile, water, methanol, etc., in a temperature range of about 0 ° C. to 150 ° C., preferably in a temperature range of about 0 ° C. to 100 ° C. It is done.

  The amount of the onium salt of the formula (3) is usually about 0.5 to 2 mol with respect to 1 mol of the salt represented by the formula (1) or the formula (2). These compounds (V) or (VI) may be taken out by recrystallization or washed with water and purified.

（式（４）および式（５）中、Ｅ及びＺ’は上記と同義。）
で表されるアルコールと、式（６）
Ｍ^{＋ −}Ｏ_３ＳＣＦ_２ＣＯＯＨ （６）
（式（６）中、Ｍは、上記と同義。）
で表されるカルボン酸とを、それぞれエステル化反応させる方法が挙げられる。 As a manufacturing method of the salt represented by Formula (1) or Formula (2) used for manufacture of Formula (V) or Formula (VI), for example, first, Formula (4) or Formula (5)

(In Formula (4) and Formula (5), E and Z ′ have the same meanings as described above.)
An alcohol represented by formula (6)
^{_{M + - O 3 SCF 2 COOH}} (6)
(In formula (6), M is as defined above.)
The method of making esterification reaction with each carboxylic acid represented by these is mentioned.

Alternatively, the alcohol represented by formula (4) or formula (5) and formula (7)
FO ₂ SCF ₂ COOH (7)
There is also a method in which each of the carboxylic acids represented by formula (1) is esterified and then hydrolyzed with MOH (M is as defined above) to obtain a salt represented by formula (1) or formula (2).

The esterification reaction is usually performed in an aprotic solvent such as dichloroethane, toluene, ethylbenzene, monochlorobenzene, acetonitrile, etc., in a temperature range of about 20 ° C. to 200 ° C., preferably in a temperature range of about 50 ° C. to 150 ° C. And stirring. In the esterification reaction, an organic acid such as p-toluenesulfonic acid and / or an inorganic acid such as sulfuric acid is usually added as an acid catalyst.
Further, the esterification reaction is preferably carried out while dehydrating using a Dean Stark apparatus or the like because the reaction time tends to be shortened.

  The amount of the carboxylic acid represented by the formula (6) in the esterification reaction is about 0.2 to 3 mol, preferably about 1 to 3 mol of the alcohol represented by the formula (4) or the formula (5). It is about 0.5 to 2 mol. The acid catalyst in the esterification reaction may be a catalytic amount or an amount corresponding to a solvent, and is usually about 0.001 mol to about 5 mol.

Furthermore, there is also a method for obtaining a salt represented by the formula (VI) or the formula (2) by reducing the salt represented by the formula (V) or the formula (1).
Such a reduction reaction is carried out by using sodium borohydride in a solvent such as water, alcohol, acetonitrile, N, N-dimethylformamide, diglyme, tetrahydrofuran, diethyl ether, dichloromethane, 1,2-dimethoxyethane, or benzene. , zinc borohydride, tri sec-butyl lithium borohydride, borohydride compounds such as borane, lithium tri t- butoxy aluminum hydride, aluminum hydride compounds such as diisobutylaluminum hydride, Et 3 _SiH, such as Ph ₂ SiH ₂ organic silicon hydride compound of can be carried out using a reducing agent of an organic tin hydride compounds such as Bu 3 _SnH. The reaction can be carried out with stirring in a temperature range of about −80 ° C. to 100 ° C., preferably in a temperature range of about −10 ° C. to 60 ° C.

（式中、Ｒ^７は、直鎖、分岐鎖もしくは環状のアルキル基又はフッ素化アルキル基を表す。Ｘａは、少なくとも１つの水素原子がフッ素原子で置換された炭素数２〜６のアルキレン基を表し；Ｙａ、Ｚａは、それぞれ独立に、少なくとも１つの水素原子がフッ素原子で置換された炭素数１〜１０のアルキル基を表す。Ｒ^１０は置換もしくは非置換の炭素数１〜２０の直鎖状、分岐状又は環状のアルキル基又は置換もしくは非置換の炭素数６〜１４のアリール基を示す。） Moreover, you may use the photoacid generator shown to the following (B1) and (B2) as a photoacid generator (B).
(B1) is not particularly limited as long as it has a hydroxyl group in the cation and generates an acid upon exposure. Examples of such cations include those represented by the formula (IV) described above.
The anion in (B1) is not specifically limited, For example, what is known as an anion of an onium salt type acid generator can be used suitably.
For example, an anion represented by general formula (X-1), an anion represented by general formula (X-2), (X-3), or (X-4) can be used.

(In the formula, R ⁷ represents a linear, branched or cyclic alkyl group or a fluorinated alkyl group. Xa represents an alkylene group having 2 to 6 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom. And Ya and Za each independently represent an alkyl group having 1 to 10 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom, and R ¹⁰ is a substituted or unsubstituted straight chain having 1 to 20 carbon atoms. Or a branched or cyclic alkyl group or a substituted or unsubstituted aryl group having 6 to 14 carbon atoms.)

The linear or branched alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.
R ⁷ as the cyclic alkyl group is more preferably 4 to 15 carbon atoms, further 4 to 12 carbon atoms, 4 to 10 carbon atoms, 5 to 10 carbon atoms, and 6 to 10 carbon atoms.
The fluorinated alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.
The fluorination rate of the fluorinated alkyl group (the ratio of the number of fluorine atoms substituted by fluorination to the total number of hydrogen atoms in the alkyl group before fluorination, the same shall apply hereinafter) is preferably 10 to 100%, More preferably, it is 50 to 100%, and in particular, one in which all hydrogen atoms are substituted with fluorine atoms is preferable because the strength of the acid becomes strong.
R ⁷ is more preferably a linear or cyclic alkyl group or a fluorinated alkyl group.

In the general formula (X-2), Xa is a linear or branched alkylene group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkylene group preferably has 2 to 6 carbon atoms. More preferably 3 to 5 carbon atoms, most preferably 3 carbon atoms.
In general formula (X-3), Ya and Za are each independently a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and the carbon number of the alkyl group is Preferably it is 1-10, More preferably, it is C1-C7, Most preferably, it is C1-C3.
The number of carbon atoms of the alkylene group of Xa or the number of carbon atoms of the alkyl groups of Ya and Za is preferably as small as possible because the solubility in a resist solvent is good within the above-mentioned carbon number range.

  In addition, in the alkylene group of Xa or the alkyl group of Ya or Za, the greater the number of hydrogen atoms substituted with fluorine atoms, the stronger the acid, and the transparency to high-energy light and electron beams of 200 nm or less. Is preferable. The fluorination rate of the alkylene group or alkyl group is preferably 70 to 100%, more preferably 90 to 100%, and most preferably a perfluoroalkylene group or perfluoro group in which all hydrogen atoms are substituted with fluorine atoms. It is an alkyl group.

Examples of the aryl group include phenyl, tolyl, xylyl, cumenyl, mesityl, naphthyl, biphenyl, anthryl, phenanthryl and the like.
Examples of the substituent that may be substituted on the alkyl group and the aryl group include a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms, an ether group, an ester group, a carbonyl group, a cyano group, Examples of the substituent include one or more of an amino group, an alkyl group-substituted amino group having 1 to 4 carbon atoms, and an amide group.
In addition, you may combine with the anion represented by A ^<+> in Formula (I) etc. as an anion of (B1).

(B1) is preferably one in which the anion is represented by the above formula (X-1), and more preferably R ⁷ is a fluorinated alkyl group.
For example, the following photo acid generator is illustrated as (B1).

(B2) is not particularly limited as long as it does not have a hydroxyl group in the cation, and those that have been proposed as acid generators for chemically amplified resists can be used.
Examples of such acid generators include onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators, bisalkyl or bisarylsulfonyldiazomethanes, and diazomethanes such as poly (bissulfonyl) diazomethanes. Examples include acid generators, nitrobenzyl sulfonate acid generators, imino sulfonate acid generators, disulfone acid generators, and the like.

（式中、Ｒ^５１は、直鎖、分岐鎖もしくは環状のアルキル基、又は直鎖、分岐鎖もしくは環状のフッ素化アルキル基を表し；Ｒ^５２は、水素原子、水酸基、ハロゲン原子、直鎖もしくは分岐鎖状のアルキル基、直鎖もしくは分岐鎖状のハロゲン化アルキル基、又は直鎖もしくは分岐鎖状のアルコキシ基であり；Ｒ^５３は置換基を有していてもよいアリール基であり；ｔは１〜３の整数である。） As the onium salt acid generator, for example, an acid generator represented by the general formula (XI) can be suitably used.

(Wherein R ⁵¹ represents a linear, branched or cyclic alkyl group, or a linear, branched or cyclic fluorinated alkyl group; R ⁵² represents a hydrogen atom, a hydroxyl group, a halogen atom, linear or A branched alkyl group, a linear or branched halogenated alkyl group, or a linear or branched alkoxy group; R ⁵³ is an optionally substituted aryl group; t Is an integer from 1 to 3.)

In the general formula (XI), R ⁵¹ can be exemplified by the same carbon number, fluorination rate, and the like as the substituent R ⁷ described above.
R ⁵¹ is most preferably a linear alkyl group or a fluorinated alkyl group.

Examples of the halogen atom include a fluorine atom, a bromine atom, a chlorine atom, and an iodine atom, and a fluorine atom is preferable.
In ^R52 , the alkyl group is linear or branched, and the number of carbon atoms thereof is preferably 1 to 5, particularly 1 to 4, and more preferably 1 to 3.
In R ⁵² , the halogenated alkyl group is a group in which part or all of the hydrogen atoms in the alkyl group are substituted with halogen atoms. Examples of the alkyl group and the substituted halogen atom are the same as those described above. In the halogenated alkyl group, 50 to 100% of the total number of hydrogen atoms are preferably substituted with halogen atoms, and more preferably all are substituted.
In ^R52 , the alkoxy group is linear or branched, and the number of carbon atoms is preferably 1 to 5, particularly 1 to 4, and more preferably 1 to 3.
R ⁵² is preferably a hydrogen atom among these.

R ⁵³ is preferably a phenyl group from the viewpoint of absorption of exposure light such as ArF excimer laser.
Examples of the substituent in the aryl group include a hydroxyl group, a lower alkyl group (straight or branched chain, for example, 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms, particularly preferably a methyl group), and a lower alkoxy group. Etc.
As the aryl group for R ^53, an aryl group having no substituent is more preferable.
t is an integer of 1 to 3, preferably 2 or 3, and particularly preferably 3.

Examples of the acid generator represented by the formula (XI) include the following compounds.

  Further, as the onium salt acid generator, for example, acid generators represented by the general formulas (XII) and (XIII) may be used.

（式中、Ｒ^２１〜Ｒ^２３及びＲ^２５〜Ｒ^２６は、それぞれ独立して、アリール基又はアルキル基を表し；Ｒ^２４は、直鎖、分岐又は環状のアルキル基又はフッ素化アルキル基を表し；Ｒ^２１〜Ｒ^２３のうち少なくとも１つはアリール基を表し、Ｒ^２５〜Ｒ^２６のうち少なくとも１つはアリール基を表す。）

Wherein R ^{21 to} R ²³ and R ^{25 to} R ²⁶ each independently represents an aryl group or an alkyl group; R ²⁴ represents a linear, branched or cyclic alkyl group or a fluorinated alkyl group. And at least one of R ^{21 to} R ²³ represents an aryl group, and at least one of R ^{25 to} R ²⁶ represents an aryl group.)

As R ^{21 to} R ²³ , two or more are preferably aryl groups, and all of R ^{21 to} R ²³ are most preferably aryl groups.
The aryl group of R ^{21 to} R ²³ is, for example, an aryl group having 6 to 20 carbon atoms, and in this aryl group, part or all of the hydrogen atoms are substituted with an alkyl group, an alkoxy group, a halogen atom, or the like. May be. The aryl group is preferably an aryl group having 6 to 10 carbon atoms because it can be synthesized at a low cost. Specific examples include a phenyl group and a naphthyl group.
As the alkyl group that may be substituted for the hydrogen atom of the aryl group, an alkyl group having 1 to 5 carbon atoms is preferable, and is a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. Most preferred.

As the alkoxy group that may be substituted on the hydrogen atom of the aryl group, an alkoxy group having 1 to 5 carbon atoms is preferable, and a methoxy group and an ethoxy group are most preferable.
The halogen atom that may be substituted for the hydrogen atom of the aryl group is preferably a fluorine atom.
The alkyl group of R ²¹ to R ^23, for example, a straight, include alkyl groups such as branched or cyclic. It is preferable that it is C1-C5 from the point which is excellent in resolution. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a nonyl group, and a decanyl group. A methyl group is preferable because it is excellent in resolution and can be synthesized at low cost.
Among these, R ^{21 to} R ²³ are most preferably a phenyl group or a naphthyl group, respectively.
R ²⁴ is exemplified by those similar to R ⁷ described above.

All of R ^{25 to} R ²⁶ are preferably aryl groups.
Among these, it is most preferable that all of R ^{25 to} R ²⁶ are phenyl groups.

As specific examples of the onium salt acid generators represented by the formulas (XII) and (XIII),
Trifluoromethanesulfonate or nonafluorobutanesulfonate of diphenyliodonium, trifluoromethanesulfonate or nonafluorobutanesulfonate of bis (4-tert-butylphenyl) iodonium,
Trifluoromethanesulfonate of triphenylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate,
Trifluoromethanesulfonate of tri (4-methylphenyl) sulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate,
Dimethyl (4-hydroxynaphthyl) sulfonium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate,
Trifluoromethanesulfonate of monophenyldimethylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate,
Trifluoromethanesulfonate of diphenylmonomethylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate,
(4-methylphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate,
(4-methoxyphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate,
Trifluoromethanesulfonate of tri (4-tert-butyl) phenylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate,
Trifluoromethanesulfonate of diphenyl (1- (4-methoxy) naphthyl) sulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate,
Trifluoromethanesulfonate of di (1-naphthyl) phenylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate,
1- (4-n-Butoxynaphthyl) tetrahydrothiophenium perfluoroocranesulfonate, 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate ,
N-nonafluorobutanesulfonyloxybicyclo [2.2.1] hept-5-ene-2,3-dicarboximide and the like can be mentioned.
Moreover, the onium salt which the anion of these onium salts replaced with methanesulfonate, n-propanesulfonate, n-butanesulfonate, and n-octanesulfonate can also be used.

  Moreover, the onium salt type acid generator which replaced the anion with the anion represented by Formula (X-1)-(X-3) in general formula (XII) or (XIII) can also be used.

Furthermore, the following compounds may be used.

式中、Ｒ^３１、Ｒ^３２はそれぞれ独立に有機基を表す。 The oxime sulfonate acid generator is a compound having at least one group represented by the formula (XIV), and has a property of generating an acid upon irradiation with radiation. Such oxime sulfonate-based acid generators are frequently used for chemically amplified resist compositions, and can be arbitrarily selected and used.

In the formula, R ³¹ and R ³² each independently represents an organic group.

The organic group of R ³¹ and R ^{32 is} a group containing a carbon atom, and may have an atom other than a carbon atom (for example, a hydrogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, or a halogen atom).
As the organic group for R ³¹ , a linear, branched, or cyclic alkyl group or aryl group is preferable. These alkyl groups and aryl groups may have a substituent. There is no restriction | limiting in particular as this substituent, For example, a fluorine atom, a C1-C6 linear, branched or cyclic alkyl group etc. are mentioned.
As an alkyl group, C1-C20 is preferable, C1-C10 is more preferable, C1-C8 is more preferable, C1-C6 is especially preferable, and C1-C4 is the most preferable. As the alkyl group, a partially or completely halogenated alkyl group (hereinafter sometimes referred to as a halogenated alkyl group) is particularly preferable. The partially halogenated alkyl group means an alkyl group in which a part of hydrogen atoms is substituted with a halogen atom, and the fully halogenated alkyl group means that all of the hydrogen atoms are halogen atoms. Means an alkyl group substituted with Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable. That is, the halogenated alkyl group is preferably a fluorinated alkyl group.
The aryl group preferably has 4 to 20 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms. As the aryl group, a partially or completely halogenated aryl group is particularly preferable.
R ³¹ is particularly preferably a C 1-4 alkyl group having no substituent or a C 1-4 fluorinated alkyl group.

As the organic group for R ³² , a linear, branched, or cyclic alkyl group, aryl group, or cyano group is preferable. ^Examples of the alkyl group and aryl group for R ³² include the same alkyl groups and aryl groups as those described for R ³¹ .
R ³² is particularly preferably a cyano group, an alkyl group having 1 to 8 carbon atoms having no substituent, or a fluorinated alkyl group having 1 to 8 carbon atoms.

式（XVII）中、Ｒ^３３は、シアノ基、置換基を有さないアルキル基又はハロゲン化アルキル基である。Ｒ^３４はアリール基である。Ｒ^３５は置換基を有さないアルキル基又はハロゲン化アルキル基である。
式（XVIII）中、Ｒ^３６はシアノ基、置換基を有さないアルキル基又はハロゲン化アルキル基である。Ｒ^３７は２又は３価の芳香族炭化水素基である。Ｒ^３８は置換基を有さないアルキル基又はハロゲン化アルキル基である。ｗは２又は３、好ましくは２である。 More preferable examples of the oxime sulfonate acid generator include compounds represented by the formula (XVII) or (XVIII).

In formula (XVII), R ³³ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³⁴ is an aryl group. R ³⁵ represents an alkyl group having no substituent or a halogenated alkyl group.
In the formula (XVIII), R ³⁶ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³⁷ is a divalent or trivalent aromatic hydrocarbon group. ^R38 is an alkyl group having no substituent or a halogenated alkyl group. w is 2 or 3, preferably 2.

In general formula (XVII), the alkyl group or halogenated alkyl group having no substituent of R ³³ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and 1 to 1 carbon atoms. 6 is most preferred.
R ³³ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³³ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more, and still more preferably 90% or more. Most preferably, it is a fully fluorinated alkyl group in which a hydrogen atom is 100% fluorine-substituted. This is because the strength of the acid generated increases.

Examples of the aryl group of R ³⁴ include a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthracel group, a phenanthryl group, a group obtained by removing one hydrogen atom from an aromatic hydrocarbon ring, and a ring of these groups. Examples include heteroaryl groups in which part of the carbon atoms constituting the hetero atom is substituted with a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom. Among these, a fluorenyl group is preferable.
The aryl group of R ³⁴ may have a substituent such as an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, or an alkoxy group. The alkyl group or halogenated alkyl group in the substituent preferably has 1 to 8 carbon atoms, and more preferably 1 to 4 carbon atoms. The halogenated alkyl group is preferably a fluorinated alkyl group.
Examples of the alkyl group or halogenated alkyl group having no substituent for R ³⁵ are the same as those for R ³³ described above.

In general formula (XVIII), examples of the alkyl group or halogenated alkyl group having no substituent for R ³⁶ include the same groups as those described above for R ³³ .
Examples of the divalent or trivalent aromatic hydrocarbon group for R ³⁷ include groups obtained by further removing one or two hydrogen atoms from the aryl group for R ³⁴ .
Examples of the alkyl group or halogenated alkyl group having no substituent for R ³⁸ include the same groups as those described above for R ³⁵ .

Specific examples of the oxime sulfonate acid generator include compounds described in paragraph [0122] of JP-A-2007-286161, and [Chemical Formula 18] of paragraphs [0012] to [0014] in JP-A-9-208554. The oxime sulfonate-based acid generator disclosed in [Chemical Formula 19], the oxime sulfonate-based acid generator disclosed in Examples 1 to 40 on pages 65 to 85 of WO2004 / 074242A2, and the like may be used.
Moreover, the following can be illustrated as a suitable thing.

Among diazomethane acid generators, specific examples of bisalkyl or bisarylsulfonyldiazomethanes include bis (isopropylsulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane, Examples include bis (cyclohexylsulfonyl) diazomethane, bis (2,4-dimethylphenylsulfonyl) diazomethane, and the like.
Further, diazomethane acid generators disclosed in JP-A-11-035551, JP-A-11-035552, and JP-A-11-035573 can also be suitably used.
Examples of the poly (bissulfonyl) diazomethanes include 1,3-bis (phenylsulfonyldiazomethylsulfonyl) propane and 1,4-bis (phenylsulfonyldiazomethylsulfonyl) disclosed in JP-A-11-322707. ) Butane, 1,6-bis (phenylsulfonyldiazomethylsulfonyl) hexane, 1,10-bis (phenylsulfonyldiazomethylsulfonyl) decane, 1,2-bis (cyclohexylsulfonyldiazomethylsulfonyl) ethane, 1,3-bis (Cyclohexylsulfonyldiazomethylsulfonyl) propane, 1,6-bis (cyclohexylsulfonyldiazomethylsulfonyl) hexane, 1,10-bis (cyclohexylsulfonyldiazomethylsulfonyl) decane, etc. That.

Among these, it is preferable to use an onium salt having a fluorinated alkyl sulfonate ion as an anion as the component (B2).
In the present invention, any of the photoacid generators can be used alone or in admixture of two or more.
The resist composition used in the present invention has a resin (A) of about 70 to 99.9% by weight, a photoacid generator of about 0.1 to 30% by weight, 0.1 to 0.1% based on the total solid content. It is preferable to contain in the range of about 20% by weight, more preferably about 1-10% by weight. By setting it within this range, the pattern can be sufficiently formed, a uniform solution is obtained, and the storage stability is improved.

The crosslinking agent (C) is not particularly limited, and can be appropriately selected from among crosslinking agents used in the field.
Specifically, amino group-containing compounds such as acetoguanamine, benzoguanamine, urea, ethylene urea, propylene urea, glycoluril, etc. are reacted with formaldehyde or formaldehyde and a lower alcohol, and the hydrogen atom of the amino group is hydroxymethyl group or lower A compound substituted with an alkoxymethyl group; an aliphatic hydrocarbon having two or more ethylene oxide structural moieties; and the like. Among these, in particular, those using urea are urea-based crosslinking agents, those using alkylene ureas such as ethylene urea and propylene urea are alkylene urea-based crosslinking agents, and those using glycoluril are glycoluril-based crosslinking agents. Of these, urea-based crosslinking agents, alkylene urea-based crosslinking agents, glycoluril-based crosslinking agents, and the like are preferable, and glycoluril-based crosslinking agents are more preferable.

  Urea-based crosslinking agents include compounds in which urea and formaldehyde are reacted to replace amino group hydrogen atoms with hydroxymethyl groups; urea, formaldehyde and lower alcohols are reacted to convert amino group hydrogen atoms into lower alkoxy groups. Examples include compounds substituted with a methyl group. Specific examples include bismethoxymethylurea, bisethoxymethylurea, bispropoxymethylurea, bisbutoxymethylurea and the like. Of these, bismethoxymethylurea is preferred.

  Examples of the alkylene urea crosslinking agent include compounds represented by general formula (XIX).

式中、Ｒ^８とＲ^９は、それぞれ独立に、水酸基又は低級アルコキシ基であり、Ｒ^８’とＲ^９’は、それぞれ独立に、水素原子、水酸基又は低級アルコキシ基であり、ｖは０又は１〜２の整数である。
Ｒ^８’とＲ^９’が低級アルコキシ基であるとき、好ましくは炭素数１〜４のアルコキシ基であり、直鎖状でもよく分岐状でもよい。Ｒ^８’とＲ^９’は同じであってもよく、互いに異なっていてもよい。同じであることがより好ましい。
Ｒ^８とＲ^９が低級アルコキシ基であるとき、好ましくは炭素数１〜４のアルコキシ基であり、直鎖状でもよく分岐状でもよい。Ｒ^８とＲ^９は同じであってもよく、互いに異なっていてもよい。同じであることがより好ましい。
ｖは０又は１〜２の整数であり、好ましくは０又は１である。
アルキレン尿素系架橋剤としては、特に、ｖが０である化合物（エチレン尿素系架橋剤）及び／又はｖが１である化合物（プロピレン尿素系架橋剤）が好ましい。

In the formula, R ⁸ and R ⁹ are each independently a hydroxyl group or a lower alkoxy group, R ^{8 ′} and R ^{9 ′} are each independently a hydrogen atom, a hydroxyl group or a lower alkoxy group, and v is 0 or It is an integer of 1-2.
When R ^{8 ′} and R ^{9 ′} are lower alkoxy groups, they are preferably alkoxy groups having 1 to 4 carbon atoms, and may be linear or branched. R ^{8 ′} and R ^{9 ′} may be the same or different from each other. More preferably, they are the same.
When R ⁸ and R ⁹ are lower alkoxy groups, they are preferably alkoxy groups having 1 to 4 carbon atoms, and may be linear or branched. R ⁸ and R ⁹ may be the same or different from each other. More preferably, they are the same.
v is 0 or an integer of 1 to 2, and preferably 0 or 1.
As the alkylene urea crosslinking agent, a compound in which v is 0 (ethylene urea crosslinking agent) and / or a compound in which v is 1 (propylene urea crosslinking agent) are particularly preferable.

  The compound represented by the general formula (XIII) can be obtained by condensation reaction of alkylene urea and formalin, and by reacting this product with a lower alcohol.

  Specific examples of alkylene urea crosslinking agents include mono and / or dihydroxymethylated ethylene urea, mono and / or dimethoxymethylated ethylene urea, mono and / or diethoxymethylated ethylene urea, mono and / or dipropoxymethylated Ethylene urea crosslinkers such as ethylene urea, mono and / or dibutoxymethylated ethylene urea; mono and / or dihydroxymethylated propylene urea, mono and / or dimethoxymethylated propylene urea, mono and / or diethoxymethylated propylene Propylene urea crosslinkers such as urea, mono and / or dipropoxymethylated propylene urea, mono and / or dibutoxymethylated propylene urea; 1,3-di (methoxymethyl) 4,5-dihydroxy-2-imidazolid Non, 1,3-di (methoxymethyl -4,5-dimethoxy-2-imidazolidinone.

Examples of the glycoluril-based crosslinking agent include glycoluril derivatives in which the N position is substituted with one or both of a hydroxyalkyl group and an alkoxyalkyl group having 1 to 4 carbon atoms. This glycoluril derivative can be obtained by condensation reaction of glycoluril and formalin, and by reacting this product with a lower alcohol.
The glycoluril-based cross-linking agent is, for example, mono, di, tri and / or tetrahydroxymethylated glycoluril, mono, di, tri and / or tetramethoxymethylated glycoluril, mono, di, tri and / or tetraethoxymethyl. Glycoluril, mono, di, tri and / or tetrapropoxymethylated glycoluril, mono, di, tri and / or tetrabutoxymethylated glycoluril.

A crosslinking agent (C) may be used independently and may be used in combination of 2 or more type.
The content of the crosslinking agent (C) is preferably 0.5 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, and most preferably 1 to 5 parts by mass with respect to 100 parts by mass of the resin (A) component. . By setting it within this range, the cross-linking can proceed sufficiently and a good resist pattern can be obtained, the storage stability of the resist coating solution is improved, and deterioration of sensitivity over time can be suppressed.

In addition, although the resist composition used by this invention may contain a thermal acid generator, it is preferable not to contain. Here, the thermal acid generator is a compound that is stable at a temperature lower than the hard baking temperature (described later) of the resist in which the thermal acid generator is used, but decomposes at a temperature higher than the hard baking temperature and generates an acid. In contrast, a photoacid generator refers to a compound that is stable at a pre-bake temperature (described later) or a post-exposure bake temperature (described later) and generates an acid upon exposure. These distinctions can be fluid depending on the mode of use of the present invention. That is, in the same resist, it may function as both a thermal acid generator and a photoacid generator or may function only as a photoacid generator depending on the applied process temperature. In some resists, it does not function as a thermal acid generator, but in other resists it may function as a thermal acid generator.
Examples of thermal acid generators include various known thermal acid generators such as benzoin tosylate, nitrobenzyl tosylate (particularly 4-nitrobenzyl tosylate), and other organic sulfonic acid alkyl esters. However, in the present invention, it is preferable not to use these thermal acid generators. However, when a thermal acid generator is used, it is suitable to suppress it to about 0.05 parts by mass or less with respect to 100 parts by mass of the resin (A).

  The resist composition used in the present invention preferably contains a basic compound, preferably a basic nitrogen-containing organic compound, particularly an amine or ammonium salt. By adding a basic compound, the basic compound can act as a quencher to improve performance deterioration due to deactivation of the acid accompanying holding after exposure. When using a basic compound, it is preferable to contain in the range of about 0.01 to 1 weight% on the basis of the total solid content of the resist composition.

Examples of such basic compounds include those represented by the following formulas.

In the formula, R ¹¹ and R ¹² each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, or an aryl group. The alkyl group preferably has about 1 to 6 carbon atoms, the cycloalkyl group preferably has about 5 to 10 carbon atoms, and the aryl group preferably has about 6 to 10 carbon atoms. Have
R ¹³ , R ¹⁴ and R ¹⁵ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group or an alkoxy group. Examples of the alkyl group, cycloalkyl group, and aryl group are the same as those for R ¹¹ and R ¹² . The alkoxy group preferably has 1 to 6 carbon atoms.

R ¹⁶ represents an alkyl group or a cycloalkyl group. Examples of the alkyl group and cycloalkyl group are the same as those for R ¹¹ and R ¹² .
R ¹⁷ , R ¹⁸ , R ¹⁹ and R ²⁰ each independently represents an alkyl group, a cycloalkyl group or an aryl group. Examples of the alkyl group, cycloalkyl group and aryl group are the same as those for R ¹¹ , R ¹² and R ¹⁷ .
Further, at least one hydrogen atom on the alkyl group, cycloalkyl group, or alkoxy group is independently substituted with a hydroxyl group, an amino group, or an alkoxy group having about 1 to 6 carbon atoms. Also good. At least one hydrogen atom on the amino group may be substituted with an alkyl group having 1 to 4 carbon atoms.
W represents an alkylene group, a carbonyl group, an imino group, a sulfide group or a disulfide group. The alkylene group preferably has about 2 to 6 carbon atoms.
Further, in R ^{11 to} R ²⁰ , any of those that can take both a linear structure and a branched structure may be used.
Specific examples of such a compound include those exemplified in JP-A-2006-257078.
Also, a hindered amine compound having a piperidine skeleton as disclosed in JP-A-11-52575 can be used as a quencher.

  The resist composition used in the present invention further contains various additives known in the art, such as sensitizers, dissolution inhibitors, other resins, surfactants, stabilizers, and dyes, as necessary. May be.

The resist composition used in the present invention is usually used as a resist solution composition in a state where each of the above components is dissolved in a solvent. Such a resist composition is used as at least a first resist composition. As a result, it can be used in a so-called double imaging method, and in this double imaging method, a fine resist pattern with a pattern pitch reduced by half can be obtained by repeating the processes of resist coating, exposure and development twice. Such a step may be repeated three or more times (N times). As a result, a finer resist pattern having a pattern pitch of 1 / N can be obtained. The present invention can be suitably applied to such double and triple imaging methods and multiple imaging methods.
Note that the above-described resist composition may be used as the second resist composition. In this case, the composition is not necessarily the same as that of the first resist composition.

In the resist processing method of the present invention, first, the above-described resist solution composition (hereinafter sometimes referred to as the first resist composition) is applied onto a substrate and dried to obtain a first resist film. . Here, the film thickness of the first resist film is not particularly limited, but in the film thickness direction, it is suitable to set it to a level that allows sufficient exposure and development in a subsequent process. , 0. Several micrometers to several millimeters can be mentioned.
The substrate is not particularly limited, and various substrates such as a semiconductor substrate such as a silicon wafer, a plastic, metal or ceramic substrate, an insulating film, or a conductive film formed on these substrates are used. it can.
The method for applying the composition is not particularly limited, and a method that is usually used industrially, such as spin coating, can be used.

Any solvent can be used as long as it can dissolve each component, has an appropriate drying speed, and gives a uniform and smooth coating film after the solvent evaporates. Usually, solvents generally used in the art are suitable.
For example, glycol ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate and propylene glycol monomethyl ether acetate, glycol ethers such as propylene glycol monomethyl ether, esters such as ethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate , Ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone, cyclic esters such as γ-butyrolactone, and the like. These solvents can be used alone or in combination of two or more.

  Examples of the drying include natural drying, ventilation drying, and reduced pressure drying. A specific heating temperature is suitably about 10 to 120 ° C, and preferably about 25 to 80 ° C. The heating time is suitably about 10 seconds to 60 minutes, preferably about 30 seconds to 30 minutes.

Next, the obtained first resist film is pre-baked. Prebaking is, for example, in the temperature range of about 80 to 140 ° C., for example, in the range of about 30 seconds to 10 minutes.
Subsequently, an exposure process for patterning is performed. The exposure process is preferably performed using an exposure apparatus ordinarily used in the field, such as a scanning stepper type projection exposure apparatus (exposure apparatus) that is a scanning exposure type. The exposure light source emits ultraviolet laser light such as KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), F ₂ laser (wavelength 157 nm), solid-state laser light source (YAG or semiconductor laser, etc.) Various types of laser beam can be used, such as those that convert the wavelength of the laser beam from) to radiate a harmonic laser beam in the far ultraviolet region or the vacuum ultraviolet region.

Thereafter, the obtained first resist film is post-exposure baked. By this heat treatment, the deprotecting group reaction can be promoted. The heat treatment here includes, for example, a temperature range of about 70 to 140 ° C., for example, a range of about 30 seconds to 10 minutes.
Subsequently, development is performed with a first alkaline developer to obtain a first resist pattern. As the alkaline developer, various alkaline aqueous solutions used in this field can be used. Usually, an aqueous solution of tetramethylammonium hydroxide, (2-hydroxyethyl) trimethylammonium hydroxide (commonly called choline) or the like is used.
Thereafter, the obtained first resist pattern is hard baked. By this heat treatment, the crosslinking reaction can be promoted. The heat treatment here is, for example, a relatively high temperature range of about 120 to 250 ° C., for example, a range of about 30 seconds to 10 minutes.

Further, a second resist composition is applied on the first resist pattern formed using the resist composition described above, and dried to form a second resist film. This is pre-baked, subjected to exposure processing for patterning, and optionally heat-treated, usually post-exposure baking. Thereafter, the second resist pattern can be formed by developing with a second alkaline developer.
Examples of conditions such as coating, drying, pre-baking, exposure, and post-exposure baking for the second resist composition are the same as those for the first resist composition.
The composition of the second resist composition is not particularly limited, and any of negative and positive resist compositions may be used, and any of those known in the art can be used. Further, any of the resist compositions described above may be used, and in this case, the resist composition is not necessarily the same as the first resist composition.
In the present invention, even when subjected to two or more exposures, developments, multiple heat treatments, etc. by performing the double imaging method, the shape is still maintained and the pattern itself is not deformed. 1 resist film is used, and thereby an extremely fine pattern can be realized.

Next, an Example is given and this invention is demonstrated further more concretely. In the examples, “%” and “part” representing the content or amount used are based on weight unless otherwise specified. The weight average molecular weight is a value determined by gel permeation chromatography. The measurement conditions are as follows.
Column: TSKgel Multipore HXL-M x 3 + guardcolumn (manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Flow rate: 1.0 mL / min
Detector: RI detector Column temperature: 40 ° C
Injection volume: 100 μl
Molecular weight standard: Standard polystyrene (manufactured by Tosoh Corporation)
The monomers used in the resin synthesis are shown below.

Resin Synthesis Example 1: Synthesis of Resin Y1 55.55 parts of 1,4-dioxane was charged into a four-necked flask equipped with a thermometer and a reflux tube, and bubbled with nitrogen gas for 30 minutes. After the temperature was raised to 70 ° C. under a nitrogen seal, 30.00 parts of monomer B shown in the above figure, 11.22 parts of C, 5.79 parts of D, 24.03 parts of E, 21.54 parts of F, azo A solution in which 0.54 parts of bisisobutyronitrile, 2.43 parts of azobis-2,4-dimethylvaleronitrile, and 83.33 parts of 1,4-dioxane were added dropwise over 2 hours while maintaining 70 ° C. did. After completion of dropping, the mixture was kept at 70 ° C. for 5 hours. After cooling, the reaction solution was diluted with 101.84 parts of 1,4-dioxane. The diluted mass was poured into 1204 parts of methanol with stirring, and the precipitated resin was collected by filtration. The residue was put into a liquid of 1204 parts of methanol and filtered after stirring. The obtained filtrate was put into the same liquid, and the operations of stirring and filtering were further performed 4 times. Thereafter, vacuum drying was performed to obtain 65.4 parts of resin. This resin is designated as Y1. Yield: 71%, Mw: 12784, Mw / Mn: 1.52, Tg: 154.7 ° C.

Resin Synthesis Example 2: Synthesis of Resin Y2 In Resin Synthesis Example 1, except that 0.67 parts of azobisisobutyronitrile and 3.04 parts of azobis-2,4-dimethylvaleronitrile were used, and the reaction temperature was 65 ° C. Synthesis was performed in the same manner as in Resin Synthesis Example 1 to obtain 66.4 parts of resin. This resin is designated Y2. Yield: 72%, Mw: 14364, Mw / Mn: 1.63, Tg: 153.6 ° C.

Resin Synthesis Example 3: Synthesis of Resin Y3 Synthesis was performed in the same manner as in Resin Synthesis Example 1 except that the reaction temperature was 65 ° C. in Resin Synthesis Example 1 to obtain 68.2 parts of resin. This resin is designated Y3. Yield: 74%, Mw: 16818, Mw / Mn: 1.67, Tg: 155.7 ° C.

Resin Synthesis Example 4: Synthesis of Resin Y4 In Resin Synthesis Example 1, except that 0.34 parts of azobisisobutyronitrile and 1.52 parts of azobis-2,4-dimethylvaleronitrile were used, and the reaction temperature was 60 ° C. Synthesis was performed in the same manner as in Resin Synthesis Example 1 to obtain 72.4 parts of resin. This resin is designated as Y4. Yield: 78%, Mw: 25808, Mw / Mn: 1.83, Tg: 157.7 ° C.

Resin Synthesis Example 5: Synthesis of Resin Y5 In Resin Synthesis Example 1, except that azobisisobutyronitrile is 0.20 part, azobis-2,4-dimethylvaleronitrile is 0.91 part, and the reaction temperature is 60 ° C., Synthesis was performed in the same manner as in Resin Synthesis Example 1 to obtain 71.5 parts of resin. This resin is designated Y5. Yield: 77%, Mw: 36215, Mw / Mn: 1.88, Tg: 158.2 ° C.

Resin Synthesis Example 6: Synthesis of Resin Y6 27.78 parts of 1,4-dioxane was charged into a four-necked flask equipped with a thermometer and a reflux tube, and bubbled with nitrogen gas for 30 minutes. Then, after heating up to 73 ° C. under a nitrogen seal, 15.00 parts of monomer B, 5.61 parts of C, 2.89 parts of monomer D, 12.02 parts of E, 12.02 parts of monomer F, and 10. A solution prepared by mixing 77 parts, 0.34 parts of azobisisobutyronitrile, 1.52 parts of azobis-2,4-dimethylvaleronitrile, and 63.85 parts of 1,4-dioxane was added to It was added dropwise over time. After completion of dropping, the mixture was kept at 73 ° C. for 5 hours. After cooling, the reaction solution was diluted with 50.92 parts of 1,4-dioxane. The diluted mass was poured into a mixed solution of 481 parts of methanol and 120 parts of ion-exchanged water while stirring, and the precipitated resin was collected by filtration. The filtrate was put into 301 parts of methanol and filtered after stirring. The obtained filtrate was put into the same liquid, and the operations of stirring and filtration were further performed twice. Thereafter, vacuum drying was performed to obtain 37.0 parts of resin. This resin is set to 2. Yield: 80%, Mw: 7883, Mw / Mn: 1.96.

Resin Synthesis Example 7: Synthesis of Resin 1 A 4-neck flask equipped with a thermometer and a reflux tube was charged with 24.36 parts of methyl isobutyl ketone and bubbled with nitrogen gas for 30 minutes. After raising the temperature to 72 ° C. under a nitrogen seal, 16.20 parts of monomer A, 11.56 parts of D, 8.32 parts of F, 0.27 part of azobisisobutyronitrile, 0.27 parts of azobis- A solution in which 1.22 parts of 2,4-dimethylvaleronitrile and 29.77 parts of methyl isobutyl ketone were mixed was added dropwise over 2 hours while maintaining 72 ° C. After completion of dropping, the mixture was kept at 72 ° C. for 5 hours. After cooling, the reaction solution was diluted with 39.69 parts of methyl isobutyl ketone. The diluted mass was poured into 469 parts of methanol with stirring, and the precipitated resin was collected by filtration. The filtrate was put into a liquid of 235 parts of methanol and filtered after stirring. The obtained filtrate was put into the same liquid, and the operations of stirring and filtration were further performed twice. Thereafter, vacuum drying was performed to obtain 22.7 parts of resin. This resin is set to 1. Yield: 63%, Mw: 10124, Mw / Mn: 1.40.

Photoacid generator synthesis example 1: Synthesis of triphenylsulfonium 4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate (photoacid generator 1) (1) 100 parts of difluoro (fluorosulfonyl) acetic acid methyl ester, ion-exchanged water To 250 parts, 230 parts of a 30% aqueous sodium hydroxide solution was added dropwise in an ice bath. The mixture was refluxed at 100 ° C. for 3 hours, cooled, and neutralized with 88 parts of concentrated hydrochloric acid. The obtained solution was concentrated to obtain 164.8 parts of sodium difluorosulfoacetate (containing inorganic salt, purity 62.6%).
(2) Difluorosulfoacetate sodium salt 5.0 parts (purity 62.8%), 4-oxo-1-adamantanol 2.6 parts, ethylbenzene 100 parts, 0.8 part of concentrated sulfuric acid was added, and 30 hours Heated to reflux. After cooling, it was filtered and washed with tert-butyl methyl ether to obtain 5.5 parts of difluorosulfoacetic acid-4-oxo-1-adamantyl ester sodium salt. As a result of purity analysis by ¹ H-NMR, the purity was 35.6%.

  (3) Difluorosulfoacetic acid-4-oxo-1-adamantyl ester 5.4 parts (purity 35.6%) of sodium salt was charged, and a mixed solvent of 16 parts acetonitrile and 16 parts ion-exchanged water was added. To this was added a solution of 1.7 parts triphenylsulfonium chloride, 5 parts acetonitrile, and 5 parts ion-exchanged water. After stirring for 15 hours, the mixture was concentrated and extracted with 142 parts of chloroform. The organic layer was washed with ion exchange water, and the obtained organic layer was concentrated. The concentrated solution was repulped with 24 parts of tert-butyl methyl ether to obtain 1.7 parts of triphenylsulfonium 4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate (photoacid generator 1) as a white solid.

Photoacid generator synthesis example 2: triphenylsulfonium 1-((3-hydroxyadamantyl) methoxycarbonyl) difluoromethanesulfonate (photoacid generator 3) synthesis (1) 100 parts of difluoro (fluorosulfonyl) acetic acid methyl ester, To 150 parts of ion-exchanged water, 230 parts of a 30% aqueous sodium hydroxide solution was added dropwise in an ice bath. The mixture was refluxed at 100 ° C. for 3 hours, cooled, and neutralized with 88 parts of concentrated hydrochloric acid. The obtained solution was concentrated to obtain 164.4 parts of sodium difluorosulfoacetate (containing inorganic salt, purity 62.7%).
(2) 1.0 part of 1,1′-carbonyldiimidazole was added to 1.9 parts of difluorosulfoacetate sodium salt (purity 62.7%) and 9.5 parts of N, N-dimethylformamide and stirred for 2 hours. did. To this solution, 0.2 parts of sodium hydride was added to 1.1 parts of 3-hydroxyadamantylmethanol and 5.5 parts of N, N-dimethylformamide, and added to the solution stirred for 2 hours. After stirring for 15 hours, the produced difluorosulfoacetate-3-hydroxy-1-adamantyl methyl ester sodium salt was used as it was in the next reaction.

  (3) To the solution of difluorosulfoacetic acid-3-hydroxy-1-adamantylmethyl ester sodium salt obtained in (2) above, 17.2 parts of chloroform and 2.9 parts of a 14.8% aqueous solution of triphenylsulfonium chloride were added. did. After stirring for 15 hours, the mixture was separated, and the aqueous layer was extracted with 6.5 parts of chloroform. The organic layers were combined and washed with ion exchange water, and the resulting organic layer was concentrated. Triphenylsulfonium 1-((3-hydroxyadamantyl) methoxycarbonyl) difluoromethanesulfonate (photoacid generator 3) was added as a white solid by adding 5.0 parts of tert-butyl methyl ether to the concentrated liquid, stirring and then filtering. ) Was obtained.

実施例及び比較例
以下の各成分を混合して溶解し、さらに孔径０．２μｍのフッ素樹脂製フィルターで濾過して、各レジスト組成物を調製した。

Examples and Comparative Examples The following components were mixed and dissolved, and further filtered through a fluororesin filter having a pore size of 0.2 μm to prepare resist compositions.

なお、表１において、用いた各成分を以下に示す。

In Table 1, each component used is shown below.

<Crosslinking agent>
Crosslinker 1

<Heat acid generator>
Thermal acid generator 1:

クエンチャー３：ルチジン
クエンチャー４：テトラメチルアンモニウムハライド

<Quencher>
Quencher 1: Tetrabutylammonium hydride quencher 2: 2,6-diisopropylaniline

Quencher 3: lutidine quencher 4: tetramethylammonium halide

<Solvent>
PMEG solvent 1:
Propylene glycol monomethyl ether 285 parts 2-heptanone 35 parts Propylene glycol monomethyl ether acetate 20 parts γ-butyrolactone 3 parts PMEG solvent 2:
Propylene glycol monomethyl ether 255 parts 2-heptanone 35 parts Propylene glycol monomethyl ether acetate 20 parts γ-butyrolactone 3 parts PMEG solvent 3:
Propylene glycol monomethyl ether 170 parts 2-heptanone 35 parts Propylene glycol monomethyl ether acetate 20 parts γ-butyrolactone 3 parts

Example 1
An organic antireflection film having a thickness of 780 mm is formed by applying “ARC-29A-8”, a composition for organic antireflection film made by Brewer, to a silicon wafer and baking it at 205 ° C. for 60 seconds. A resist solution obtained by dissolving the resist composition of Example 1 in Table 1 in the PMEG solvent 1 was spin-coated thereon so that the film thickness after drying was 0.08 μm.
After applying the resist solution, it was pre-baked at 90 ° C. for 60 seconds on a direct hot plate.
The resist film thus obtained was applied to each wafer with an ArF excimer stepper ("FPA5000-AS3" manufactured by Canon, NA = 0.75, 2/3 Annular) and a 1: 1 line having a line width of 100 nm. Using a mask having an and space pattern, the pattern was exposed at an exposure amount of 35 mJ / cm ² .
After exposure, post-exposure baking was performed on a hot plate at 80 ° C. for 60 seconds.
Furthermore, paddle development was performed for 60 seconds with a 2.38 wt% tetramethylammonium hydroxide aqueous solution to form a desired pattern.
Thereafter, hard baking was performed at a temperature of 150 ° C. for 60 seconds.
When the obtained first line and space pattern was observed with a scanning electron microscope, it was confirmed that a good and precise pattern was formed.

Subsequently, on the obtained first line and space pattern, as a second resist solution, a resist solution obtained by dissolving the resist composition of Reference Example A in Table 1 in the PMEG solvent 2 has a thickness after drying. It was applied so as to have a thickness of 0.08 μm.
After applying the second resist solution, it was pre-baked on a direct hot plate at 85 ° C. for 60 seconds.

The second resist film thus obtained was rotated 90 ° on each wafer using an ArF excimer stepper (“FPA5000-AS3” manufactured by Canon, NA = 0.75, 2/3 Annular). The second line and space pattern was exposed at an exposure amount of 29 mJ / cm ² so as to be orthogonal to the first line and space pattern.
After exposure, post-exposure baking was performed on a hot plate at 85 ° C. for 60 seconds.
Further, paddle development was performed for 60 seconds with a 2.38 wt% aqueous solution of tetramethylammonium hydroxide to finally form a lattice pattern.
When the obtained 1st and 2nd line and space pattern was observed with the scanning electron microscope, while the 2nd line and space pattern was formed in the favorable shape on the 1st line and space pattern The first line and space pattern shape was maintained, and it was confirmed that a good pattern was formed as a whole. The cross-sectional shape was also good.

Examples 2-6
Except using the resist composition shown in Table 1, the 1st line and space pattern was created substantially like Example 1, and it observed with the scanning electron microscope. As a result, it was confirmed that a good and precise pattern was formed.

  Subsequently, as in Example 1, a second line and space pattern was created on the obtained first line and space pattern and observed with a scanning electron microscope. As a result, the second line and space pattern is formed in a good shape on the first line and space pattern, and the first line and space pattern shape is maintained. It was confirmed that a pattern was formed. The cross-sectional shape was also good.

Example 7
In Resin Synthesis Example 1, a resin having Mw = 10000 is obtained in substantially the same manner except that 0.60 part of azobisisobutyronitrile and 2.74 parts of azobis-2,4-dimethylvaleronitrile are obtained.
Except for changing this resin to the resin (A) of Example 1 in Table 1, first and second line and space patterns are created in substantially the same manner as in Example 1.
As a result, a good pattern can be obtained as in the first embodiment.

Example 8
In Resin Synthesis Example 1, Mw = 40000 was substantially the same except that 0.17 part of azobisisobutyronitrile, 0.79 part of azobis-2,4-dimethylvaleronitrile, and the reaction temperature was 60 ° C. To obtain a resin.
Except for changing this resin to the resin (A) of Example 1 in Table 1, first and second line and space patterns are created in substantially the same manner as in Example 1.
As a result, a good pattern can be obtained as in the first embodiment.

Comparative Examples 1-3
A first line-and-space pattern is created in the same manner as in Example 1 except that a resist composition using a resin (A) having a relatively low molecular weight shown in Table 1 is used, and is observed with a scanning electron microscope. did.
As a result, the obtained resist pattern, in particular, the first line and space pattern, was partially dissolved or a portion with a narrow line pattern width was observed, and a good pattern was not recognized.
In particular, as in Comparative Example 3, when the thermal acid generator was used, the dissolution of the first line and space pattern was significant.

Comparative Example 4
In Resin Synthesis Example 1, a resin having Mw = 70620 was obtained in substantially the same manner except that 1.34 parts of azobisisobutyronitrile was charged as an initiator and the reaction temperature was set to 60 ° C.
Except for changing this resin to the resin (A) of Example 1 in Table 1, first and second line and space patterns were prepared in substantially the same manner as in Example 1.
As a result, at the time of exposure, it became a lump in some places, no dissolution by the developer was observed, and it was not formed into a line and space pattern.

  According to the resist processing method of the present invention, in a multi-patterning method or a multi-imaging method such as a double patterning method or a double imaging method, a resist pattern obtained by a resist composition for forming a resist pattern for the first time is finely divided. And can be formed with high accuracy.

Claims (8)

(1) Resin (A), photoacid generator (B), and crosslinker (which has an acid labile group, is insoluble or hardly soluble in an aqueous alkali solution and can be dissolved in an aqueous alkali solution by acting with an acid) A step of applying a first resist composition containing C) and having a resin (A) having a weight average molecular weight of 10,000 or more and 40000 or less on a substrate and drying to obtain a first resist film;
(2) a step of pre-baking the first resist film;
(3) a step of exposing the first resist film;
(4) a step of post-exposure baking the first resist film;
(5) a step of developing with a first alkaline developer to obtain a first resist pattern;
(6) a step of hard baking the first resist pattern;
(7) A step of applying a second resist composition on the first resist pattern and drying to obtain a second resist film;
(8) a step of pre-baking the second resist film;
(9) a step of exposing the second resist film;
(10) a step of post-exposure baking the second resist film; and
(11) A step of developing with a second alkaline developer to obtain a second resist pattern,
A resist processing method.   The resist processing method according to claim 1, wherein the crosslinking agent (C) is at least one selected from the group consisting of a urea crosslinking agent, an alkylene urea crosslinking agent, and a glycoluril crosslinking agent.   The resist processing method according to claim 1 or 2, wherein the content of the crosslinking agent (C) is 0.5 to 30 parts by mass with respect to 100 parts by mass of the resin.   The acid-labile group of the resin (A) is a group having an alkyl ester or lactone ring in which the α-position of the ether bond is a quaternary carbon atom, or a group having a carboxylic acid ester. Or a resist processing method. The resist processing method according to claim 1, wherein the photoacid generator (B) is a compound represented by the formula (I).

(In the formula, R ^a represents a linear or branched hydrocarbon group having 1 to 6 carbon atoms, or a cyclic hydrocarbon group having 3 to 30 carbon atoms, and when R ^a is a cyclic hydrocarbon group, One or more of an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a perfluoroalkyl group having 1 to 4 carbon atoms, an ether group, an ester group, a hydroxy group, or a cyano group may be substituted. A ⁺ represents an organic counter ion, and Y ¹ and Y ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.) The resist processing method according to claim 1, wherein the photoacid generator (B) is a compound represented by the formula (III).

(Wherein Y ¹ and Y ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group, X represents —OH or —Y—OH (where Y represents carbon N represents an integer of 1 to 9, and A ⁺ represents an organic counter ion.) The photoacid generator (B) is a compound containing at least one cation selected from the group consisting of formulas (IIa), (IIb), (IIc), (IId) and (IV). 7. The resist processing method according to any one of 6.

(.P ^{6 wherein, P 1 ~P 5, P 10} ~P 21 is representing independently a hydrogen atom, a hydroxyl group, an alkyl group or an alkoxy group having 1 to 12 carbon atoms having 1 to 12 carbon atoms, P ⁷ is independently an alkyl group having 1 to 12 carbon atoms and a cycloalkyl group having 3 to 12 carbon atoms, or P ⁶ and P ⁷ are bonded to form a divalent valence having 3 to 12 carbon atoms. P ⁸ represents a hydrogen atom, and P ⁹ represents an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an optionally substituted aromatic group, P ⁸ and P ⁹ are combined to represent a divalent hydrocarbon group having 3 to 12 carbon atoms, D represents a sulfur atom or an oxygen atom, m is 0 or 1, and r is 1 to 3. Represents an integer.)   The weight average molecular weight of resin (A) is 12000 or more and 40000 or less, The resist processing method in any one of Claims 1-7.