JP2008241871A - Resist composition and method for forming pattern using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems in techniques for improving performance in microprocessing of semiconductor elements using actinic rays or radiation, particularly, KrF excimer laser beams, electron beams, or EUV beams; to provide a positive resist composition having high sensitivity, reduced line width roughness and density distribution dependency, and particularly in EUV exposure, showing high sensitivity as well as preferable dissolution contrast; and to provide a method for forming a pattern using the composition. <P>SOLUTION: The resist composition contains a resin having a specified repeating unit having an indenone structure and a repeating unit which is decomposed by an effect of an acid to increase alkali solubility, and a compound which generates an acid by irradiation with actinic rays or radiation. The method for forming a pattern is carried out by using the resist composition. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a positive resist composition suitably used in an ultramicrolithography process such as the manufacture of VLSI and high-capacity microchips and other photo-publishing processes. More specifically, the present invention relates to a positive photoresist capable of forming a high-definition pattern using KrF excimer laser light, electron beam, EUV light, etc., and a semiconductor device using KrF excimer laser light, electron beam, EUV light The present invention relates to a positive resist composition that can be suitably used for microfabrication and a pattern formation method using the same.

  Conventionally, in the manufacturing process of semiconductor devices such as IC and LSI, fine processing by lithography using a photoresist composition has been performed. In recent years, with the high integration of integrated circuits, the formation of ultrafine patterns in the submicron region and the quarter micron region has been required. Along with this, there is a tendency to shorten the exposure wavelength from g-line to i-line and further to KrF excimer laser light. Furthermore, at present, in addition to excimer laser light, lithography using electron beams, X-rays, or EUV light is also being developed.

  Lithography using an electron beam or EUV light is positioned as a next-generation or next-generation pattern forming technology, and a positive resist with high sensitivity and high resolution is desired. In particular, high sensitivity is a very important issue for shortening the wafer processing time. However, in positive resists for electron beams and EUV, if high sensitivity is to be pursued, not only the resolution will be lowered. The development of resists that satisfy these characteristics at the same time is strongly desired. Here, the density dependency means a pattern dimension difference between a portion where the resist pattern density is high and a portion where the resist pattern density is low. If this difference is large, the process margin becomes narrow during actual pattern formation. One of the important issues in resist technology development is how to reduce the size. High sensitivity, high resolution, good pattern shape, and good density dependence are in a trade-off relationship, and how to satisfy them simultaneously is very important.

Furthermore, in lithography using KrF excimer laser light, it is also important to satisfy high sensitivity, high resolution, good pattern shape, and good density dependency at the same time. is there.
As a resist suitable for the lithography process using KrF excimer laser light, electron beam, or EUV light, a chemically amplified resist utilizing an acid-catalyzed reaction is mainly used from the viewpoint of high sensitivity. In the resist, as a main component, a phenolic polymer (hereinafter abbreviated as a phenolic acid-decomposable resin) having a property that is insoluble or hardly soluble in an alkaline developer and becomes soluble in an alkaline developer by the action of an acid, and A chemically amplified resist composition comprising an acid generator is effectively used.

  Regarding these positive resists, some resist compositions using phenolic acid-decomposable resins obtained by copolymerizing acid-decomposable acrylate monomers having tertiary alicyclic groups as acid-decomposable groups have been known so far. . For example, positive resist compositions disclosed in Patent Documents 1 to 4 can be exemplified.

Patent Document 5 discloses a resist composition containing a coumarin derivative.
However, in any combination of these, the present situation is that the reduction in high sensitivity, high resolution, line width roughness, and density dependency in the ultrafine region is not satisfactory at the same time.
US Pat. No. 5,561,194 JP 2001-166474 A JP 2001-166478 A JP 2003-107708 A JP 2004-61794 A

  An object of the present invention is to solve the problem of performance improvement technology in microfabrication of a semiconductor device using actinic rays or radiation, particularly KrF excimer laser light, electron beam or EUV light, and has high sensitivity, It is an object of the present invention to provide a positive resist composition having reduced line width roughness and density dependence, and having high sensitivity and good dissolution contrast, particularly in EUV exposure, and a pattern forming method using the same.

As a result of intensive studies, the present inventors have surprisingly found that the object of the present invention is a resin containing a repeating unit represented by the general formula (1), and a compound that generates an acid upon irradiation with actinic rays or radiation. It is achieved by a resist composition characterized by comprising:
That is, the present invention is achieved by the following configuration.

<1> (A) A resin having a repeating unit represented by the general formula (1), which decomposes by the action of an acid to increase alkali solubility, and (B) generates an acid upon irradiation with actinic rays or radiation. A resist composition containing the compound to be used.

（１）

(1)

In general formula (1),
R ¹ represents a hydroxyl group, an alkyl group, a cycloalkyl group, an alkoxy group, a hydroxyl group substituted by an acid labile group, a cyano group, a carboxyl group substituted by an acid labile group, a cyano group or a halogen atom, When present, they may be the same or different.
x represents an integer of 0 to 2, and y represents an integer of 0 to 4.

<2> The resist composition as described in <1> above, wherein the resin (A) further contains a repeating unit represented by the general formula (2).

（２）

(2)

In general formula (2),
AR represents an aromatic ring.
Rn represents an alkyl group, a cycloalkyl group or an aryl group.
AR and Rn may be bonded to each other to form a ring.
A represents a hydrogen atom, an alkyl group, a halogen atom, a cyano group, or an alkyloxycarbonyl group.

<3> The resist composition as described in <1> or <2> above, wherein the resin (A) further contains a repeating unit represented by the general formula (3).

（３）

(3)

In general formula (3),
n represents an integer of 0 to 3. m shows the integer of 0-3. However, m + n ≦ 5.
A ₁ represents a hydrogen atom or a group containing a group that decomposes under the action of an acid, and when there are a plurality of groups, they may be the same or different.
S ₁ represents an arbitrary substituent, and when there are a plurality of them, they may be the same or different.
R ₅ represents a hydrogen atom, an alkyl group, a halogen atom, a cyano group, or an alkyloxycarbonyl group.

<4> The resist composition according to any one of <1> to <3>, further comprising an organic solvent.
<5> The resist composition according to <4>, further containing a dissolution inhibitor.
<6> The resist composition according to <5>, further containing a basic compound.
<7> A pattern forming method comprising a step of forming a resist film with the resist composition according to any one of <1> to <6>, exposing and developing the resist film.
<8> A resin having a weight average molecular weight of 1,000 to 50,000, having a repeating unit represented by the general formula (1) and a repeating unit containing an acid-decomposable group.

  According to the present invention, a positive resist composition excellent in sensitivity and resolving power as well as in pattern shape and density dependence is used for pattern formation by irradiation with an electron beam, KrF excimer laser light, EUV light, etc. A pattern forming method can be provided.

Hereinafter, the compounds used in the present invention will be described in detail.
In addition, in the description of the group (atomic group) in this specification, the description which does not describe substitution and non-substitution includes what has a substituent with what does not have a substituent. For example, the “alkyl group” includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).

  The resist composition of the present invention has a repeating unit represented by the general formula (1) and generates an acid upon irradiation with actinic rays or radiation, and a resin that decomposes by the action of an acid to increase alkali solubility. Contains compounds.

[1] Resin containing a repeating unit represented by the general formula (I) (hereinafter also referred to as resin (A))

（１）

(1)

R ¹ represents a hydroxyl group, an alkyl group, a cycloalkyl group, an alkoxy group, a hydroxyl group substituted by an acid labile group, a cyano group, a carboxyl group substituted by an acid labile group, or a plurality of halogen atoms. When doing, they may be the same or different.
Examples of the acid labile group include an acetal group (including a ketal group) and a tertiary alkyl group. When there are a plurality of R ^{1 s,} they may be bonded to each other with a divalent linking group to form a ring structure.
That is, the hydroxyl group substituted by an acid labile group and the carboxyl group substituted by an acid labile group are groups corresponding to an acid-decomposable group described later.
x represents an integer of 0 to 2, and is preferably 0. y represents an integer of 0 to 4, preferably 0 to 1.

Examples of the alkyl group as R ¹ include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a t-butyl group.
The cycloalkyl group as R ¹ preferably has 6 to 15 carbon atoms, such as a cyclohexyl group and an adamantyl group.
Examples of the alkoxy group as R ¹ include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, and an isobutoxy group.
These groups may have a substituent. Examples of the substituent include an alkoxy group, a hydroxyl group, a halogen atom, a nitro group, an acyl group, an acyloxy group, an acylamino group, a sulfonylamino group, an alkylthio group, an arylthio group, an aralkyl group. A thio group, a thiophenecarbonyloxy group, a thiophenemethylcarbonyloxy group, a heterocyclic residue and the like can be mentioned.
The group as R ¹ preferably has 10 or less carbon atoms.

As the conjugated enone monomer corresponding to the repeating unit represented by the general formula (1), commercially available ones may be used, and phenyl ketone dehydrogenation reaction, allyl alcohol oxidation reaction, and α-halogenated phenyl ketone are removed. It can be synthesized by carrying out a hydrogen halide reaction.
The repeating unit represented by the general formula (1) can be easily obtained by radical copolymerization of a corresponding conjugated enone monomer using a radical initiator.

Specific examples of the repeating unit represented by the general formula (1) are shown below, but are not limited thereto.

Furthermore, the resist composition of the present invention preferably contains a resin (A) containing a repeating unit represented by the general formula (2).

（２）

(2)

In general formula (2),
AR represents an aromatic ring.
Rn represents an alkyl group or an aryl group.
AR and Rn may be bonded to each other to form a ring.
A represents a hydrogen atom, an alkyl group, a halogen atom, a cyano group, or an alkyloxycarbonyl group.

Among the aromatic rings in AR, examples of the benzene ring include phenyl group, 4-methylphenyl group, 4-methoxyphenyl group, 4-isopropylphenyl group, 2,4-
There are dimethylphenyl group, 2,4-dimethoxyphenyl group, 2,4,6-trimethylphenyl group, 4-chlorophenyl group, 4-fluorophenyl group, 4-cyanophenyl group, 4-acetylphenyl group, preferably A phenyl group, a 4-methylphenyl group, and a 4-methoxyphenyl group; Examples of the naphthalene ring include naphthyl group, 4-methylnaphthyl group, 4-methoxynaphthyl group, 4-isopropylnaphthyl group, 2,4-dimethylnaphthyl group, 2,4-dimethoxynaphthyl group, 4-chloro Naphthyl group, 4-fluoronaphthyl group, 4-cyanonaphthyl group, 4-acetylnaphthyl group, 6-methylnaphthyl group, 6-methoxynaphthyl group, 6-isopropylnaphthyl group, 4,6-dimethylnaphthyl group, 4,6 -Dimethoxynaphthyl group, 6-chloronaphthyl group, 6-fluoronaphthyl group, 6-cyanonaphthyl group, 6-acetylnaphthyl group, etc., preferably naphthyl group.

As the alkyl group in Rn, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, pentyl group, cyclopentyl group, hexyl group, cyclohexyl group, octyl group, dodecyl group, etc. , Preferably a linear or branched alkyl group having 1 to 20 carbon atoms is used. These groups may have a substituent, and preferred substituents that may be included include an alkoxy group, a hydroxyl group, a halogen atom, a nitro group, an acyl group, an acyloxy group, an acylamino group, a sulfonylamino group, an alkylthio group, Examples include arylthio groups, aralkylthio groups, thiophenecarbonyloxy groups, thiophenemethylcarbonyloxy groups, and heterocyclic residues such as pyrrolidone residues, among which alkoxy groups, hydroxyl groups, halogen atoms, nitro groups, acyl groups, acyloxy groups, An acylamino group and a sulfonylamino group are preferred.
As the aryl group in Rn, those having 6 to 14 carbon atoms such as phenyl group, xylyl group, toluyl group, cumenyl group, naphthyl group, and anthracenyl group are preferable.

Examples of the alkyl group in A include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, pentyl group, cyclopentyl group, hexyl group, cyclohexyl group, octyl group, dodecyl group, etc. , Preferably a linear or branched alkyl group having 1 to 20 carbon atoms is used. These groups may have a substituent, and preferred substituents that may be included include an alkoxy group, a hydroxyl group, a halogen atom, a nitro group, an acyl group, an acyloxy group, an acylamino group, a sulfonylamino group, an alkylthio group, Examples include arylthio groups, aralkylthio groups, thiophenecarbonyloxy groups, thiophenemethylcarbonyloxy groups, and heterocyclic residues such as pyrrolidone residues. Among them, CF ₃ groups, alkyloxycarbonylmethyl groups, alkylcarbonyloxymethyl groups, hydroxy groups, etc. A methyl group, an alkoxymethyl group and the like are preferable.
Examples of the halogen atom in A include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the alkyl contained in the alkyloxycarbonyl group in A include the same alkyl groups as in A above.

As a feature of the skeleton of the general formula (1), when the adjacent carbon of the aromatic ring is a carbonyl carbon, it exhibits good light absorption under a KrF excimer laser, and the shape, particularly LWR, is improved. In addition, since a cyclic structure can be introduced into the polymer main chain, the glass transition temperature (Tg) of the polymer increases, thereby suppressing excessive diffusion of the acid and improving the density dependency.
The Tg of the polymer is preferably 150 ° C to 190 ° C, more preferably 160 ° C to 180 ° C.
The Tg can be measured, for example, using a measuring instrument “DSC Q1000 V7.3 Build249” and measuring a sample amount of 3 mg from 0 ° C. to 200 ° C. at a rate of temperature increase of 10 ° C./min.

  The monomer corresponding to the repeating unit represented by the general formula (2) includes (meth) acrylic acid chloride and an alcohol compound in a solvent such as THF, acetone and methylene chloride, and a basic catalyst such as triethylamine, pyridine and DBU. It can be synthesized by esterification below. A commercially available product may be used.

  Specific examples of the repeating unit represented by the general formula (2) are shown below, but are not limited thereto.

  The resin (A) preferably further contains a repeating unit represented by the general formula (3).

（３）

(3)

In general formula (3),
n represents an integer of 0 to 3. m shows the integer of 0-3. However, m + n ≦ 5.
A ₁ represents a hydrogen atom or a group containing a group that decomposes under the action of an acid, and when there are a plurality of groups, they may be the same or different.
S ₁ represents an arbitrary substituent, and when there are a plurality of them, they may be the same or different.
R ₅ represents a hydrogen atom, an alkyl group, a halogen atom, a cyano group, or an alkyloxycarbonyl group.

The group containing a group capable of decomposing by the action of an acid is a group in which A ₁ is released, resulting in a hydroxyl group in the repeating unit represented by the general formula (3), that is, an acid-decomposable group itself. It may be a group containing an acid-decomposable group, that is, a group in which an alkali-soluble group such as a hydroxyl group or a carboxyl group is generated in a residue that is decomposed by the action of an acid and bonded to a repeating unit.
Examples of the group containing a group capable of decomposing by the action of an acid include tertiary alkyl groups such as t-butyl group and t-amyl group, t-butoxycarbonyl group, t-butoxycarbonylmethyl group, —C (L ₁ ). Examples include an acetal group represented by (L ₂ ) —O—Z.
L ₁ and L ₂ may be the same or different and each represents an atom or group selected from a hydrogen atom, an alkyl group, a cycloalkyl group, or an aralkyl group.
Z represents an alkyl group, a cycloalkyl group or an aralkyl group.
Z and L ₁ may be bonded to each other to form a 5- or 6-membered ring.

When there are a plurality of S _{1 s,} each independently represents an arbitrary substituent, for example, an alkyl group, alkoxy group, acyl group, acyloxy group, aryl group, aryloxy group, aralkyl group, aralkyloxy group, hydroxy group, halogen atom , A cyano group, a nitro group, a sulfonylamino group, an alkylthio group, an arylthio group, and an aralkylthio group.
For example, as an alkyl group and a cycloalkyl group, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, a pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, an octyl group, A linear or branched alkyl group having 1 to 20 carbon atoms such as a dodecyl group or a cycloalkyl group is preferable. These groups may further have a substituent.
Further preferable substituents which may be included are alkyl group, alkoxy group, hydroxyl group, halogen atom, nitro group, acyl group, acyloxy group, acylamino group, sulfonylamino group, alkylthio group, arylthio group, aralkylthio group, thiophenecarbonyloxy Group, a thiophenemethylcarbonyloxy group, a heterocyclic residue such as a pyrrolidone residue, and the like, and a substituent having 12 or less carbon atoms is preferable.

  Examples of the alkyl group having a substituent include a cyclohexylethyl group, an alkylcarbonyloxymethyl group, an alkylcarbonyloxyethyl group, a cycloalkylcarbonyloxymethyl group, a cycloalkylcarbonyloxyethyl group, an arylcarbonyloxyethyl group, and an aralkylcarbonyloxyethyl group. , Alkyloxymethyl group, cycloalkyloxymethyl group, aryloxymethyl group, aralkyloxymethyl group, alkyloxyethyl group, cycloalkyloxyethyl group, aryloxyethyl group, aralkyloxyethyl group, alkylthiomethyl group, cycloalkylthiomethyl Group, arylthiomethyl group, aralkylthiomethyl group, alkylthioethyl group, cycloalkylthioethyl group, arylthioethyl group, aralkyl Oechiru group, and the like.

  The alkyl group and cycloalkyl group in these groups are not particularly limited, and may further have a substituent such as the aforementioned alkyl group, cycloalkyl group, or alkoxy group.

  Examples of the alkylcarbonyloxyethyl group and cycloalkylcarbonyloxyethyl group include cyclohexylcarbonyloxyethyl group, t-butylcyclohexylcarbonyloxyethyl group, n-butylcyclohexylcarbonyloxyethyl group, and the like.

The aryl group is not particularly limited, but generally includes those having 6 to 14 carbon atoms such as a phenyl group, a xylyl group, a toluyl group, a cumenyl group, a naphthyl group, an anthracenyl group, and the above-mentioned alkyl groups and cycloalkyl groups. And may have a substituent such as an alkoxy group.
Examples of the aryloxyethyl group include a phenyloxyethyl group, a cyclohexylphenyloxyethyl group, and the like. These groups may further have a substituent.

The aralkyl group is not particularly limited, and examples thereof include a benzyl group.
Examples of the aralkylcarbonyloxyethyl group include a benzylcarbonyloxyethyl group. These groups may further have a substituent.

Examples of the aralkyl group in L ₁ , L ₂ and Z include those having 7 to 15 carbon atoms such as benzyl group and phenethyl group. These groups may have a substituent.

Preferable substituents that the aralkyl group has include an alkoxy group, a hydroxyl group, a halogen atom, a nitro group, an acyl group, an acylamino group, a sulfonylamino group, an alkylthio group, an arylthio group, an aralkylthio group, and the like. Examples of the aralkyl group having a substituent include an alkoxybenzyl group, a hydroxybenzyl group, and a phenylthiophenethyl group.
The range of the carbon number of the substituent which the aralkyl group in L ₁ , L ₂ and Z may have is preferably 12 or less.

Examples of the 5- or 6-membered ring formed by combining Z and L ₁ with each other include a tetrahydropyran ring and a tetrahydrofuran ring.

  In the present invention, Z is preferably a linear or branched alkyl group. Thereby, the effect of the present invention becomes more remarkable.

  The monomer corresponding to the repeating unit represented by the general formula (3) is a hydroxy-substituted styrene monomer and a vinyl ether compound in a solvent such as THF and methylene chloride, such as p-toluenesulfonic acid and p-toluenesulfonic acid pyridine salt. It can be synthesized by acetalization in the presence of an acidic catalyst or by t-Boc protection using t-butyl dicarbonate in the presence of a basic catalyst such as triethylamine, pyridine, DBU or the like. A commercially available product may be used.

  Although the specific example of the repeating unit represented by General formula (3) below is given, it is not limited to these.

  The resin (A) preferably further has a repeating unit represented by the general formula (4).

（４）

(4)

In general formula (4),
R ₂ represents a hydrogen atom, a methyl group, a cyano group, a halogen atom, or a perfluoro group having 1 to 4 carbon atoms.
R ₃ represents a hydrogen atom, an alkyl group, a halogen atom, an aryl group, an alkoxy group or an acyl group.
p represents an integer of 0 to 4.
W represents a group that is not decomposed by the action of an acid.

  W represents a group that is not decomposed by the action of an acid (also referred to as an acid stabilizing group). Specifically, a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an acyl group, an alkylamide group, An arylamidomethyl group, an arylamide group, etc. are mentioned. The acid stabilizing group is preferably an acyl group or an alkylamide group, more preferably an acyl group, an alkylcarbonyloxy group, an alkyloxy group, a cycloalkyloxy group, or an aryloxy group.

In the acid stable group of W, the alkyl group is preferably an alkyl group having 1 to 4 carbon atoms such as methyl group, ethyl group, propyl group, n-butyl group, sec-butyl group and t-butyl group. As the alkyl group, those having 3 to 10 carbon atoms such as cyclopropyl group, cyclobutyl group, cyclohexyl group and adamantyl group are preferable, and as the alkenyl group, carbon number such as vinyl group, propenyl group, allyl group and butenyl group. Those having 2 to 4 carbon atoms are preferred, those having 2 to 4 carbon atoms such as vinyl, propenyl, allyl and butenyl groups are preferred as alkenyl groups, and phenyl, xylyl and toluyl groups are preferred as aryl groups. And those having 6 to 14 carbon atoms such as cumenyl group, naphthyl group and anthracenyl group are preferable. W may be at any position on the benzene ring, but is preferably a meta position or a para position of the styrene skeleton, particularly preferably a para position.

  Although the specific example of the repeating unit represented by General formula (4) below is given, it is not limited to these.

Resin (A) is a resin (acid-decomposable resin) whose solubility in an alkaline developer is increased by the action of an acid, and is decomposed by the action of an acid in an arbitrary repeating unit. Contains groups (acid-decomposable groups) that produce soluble groups. Examples of the alkali-soluble group include a carboxyl group and a hydroxyl group.
The repeating unit represented by the general formula (1), (2) or (3) may have an acid-decomposable group or may be contained in another repeating unit.
Examples of the acid-decomposable group include those represented by —C (═O) —X ₁ —R ₀ other than those described above.
In the formula, R ₀ is a tertiary alkyl group such as t-butyl group or t-amyl group, isobornyl group, 1-ethoxyethyl group, 1-butoxyethyl group, 1-isobutoxyethyl group, 1-cyclohexyloxy. 1-alkoxyethyl group such as ethyl group, 1-methoxymethyl group, alkoxymethyl group such as 1-ethoxymethyl group, 3-oxoalkyl group, tetrahydropyranyl group, tetrahydrofuranyl group, trialkylsilyl ester group, 3- An oxocyclohexyl ester group, a 2-methyl-2-adamantyl group, a mevalonic lactone residue and the like can be mentioned. X ₁ represents an oxygen atom, a sulfur atom, -NH -, - NHSO ₂ - or an -NHSO ₂ NH-.

As for the content rate of the repeating unit represented by General formula (1) in resin (A), 1-50 mol% is preferable in all the repeating units, More preferably, it is 1-20 mol%, Most preferably, it is 1- 10 mol%.
The content of the repeating unit having an acid-decomposable group in the resin (A) is preferably from 10 to 50 mol%, more preferably from 12 to 40 mol%, particularly preferably from 15 to 30 mol, based on all repeating units. %.
As for the content rate of the repeating unit represented by General formula (2) in resin (A), 1-50 mol% is preferable in all the repeating units, More preferably, it is 3-40 mol%, Most preferably, it is 5-5. 30 mol%.
As for the content rate of the repeating unit represented by General formula (3) in resin (A), 50-90 mol% is preferable in all the repeating units, More preferably, it is 55-85 mol%, Most preferably, it is 60- 80 mol%.

  The resin (A) may further have a repeating unit represented by the general formula (4), which is preferable from the viewpoints of improving the film quality and suppressing the decrease in film thickness of the unexposed area. The content of the repeating unit represented by the general formula (4) is preferably 0 to 50 mol%, more preferably 0 to 40 mol%, and particularly preferably 0 to 40 mol% in each of all the repeating units. 30 mol%.

  The resin (A) is copolymerized with other polymerizable monomers suitable so that an alkali-soluble group such as a phenolic hydroxyl group or a carboxyl group can be introduced in order to maintain good developability for an alkali developer. In order to improve the film quality, other hydrophobic polymerizable monomers such as alkyl acrylate and alkyl methacrylate may be copolymerized.

The weight average molecular weight (Mw) of the resin (A) is preferably in the range of 1,000 to 100,000, more preferably 1000 to 50,000, and particularly preferably 5,000 to 50,000. The dispersity (Mw / Mn) is preferably 1.0 to 10.0, more preferably 1.0 to 5.0, and particularly preferably 1.0 to 3.0.
Here, the weight average molecular weight is defined by a polystyrene conversion value of gel permeation chromatography.
The resin (A) can be synthesized by a known method such as radical polymerization.

Moreover, you may use resin (A) in combination of 2 or more types.
The total amount of the resin (A) added is generally 10 to 96% by mass, preferably 15 to 96% by mass, and particularly preferably 20 to 95% by mass with respect to the total solid content of the positive resist composition. %.

  Specific examples of the resin containing the repeating unit (A) represented by the general formula (I) are shown below, but are not limited thereto.

[2] Compound that generates acid upon irradiation with actinic ray or radiation In the resist composition of the present invention, a known compound may be used as a compound (acid generator) that generates acid upon irradiation with actinic ray or radiation. However, it is preferable to contain a compound that generates sulfonic acid upon irradiation with actinic rays or radiation (sulfonic acid generator) and / or a compound that generates carboxylic acid upon irradiation with actinic rays or radiation (carboxylic acid generator). .

<Compound (B) that generates sulfonic acid upon irradiation with actinic ray or radiation>
The compound that generates sulfonic acid upon irradiation with actinic rays or radiation contained in the resist composition of the present invention (also referred to as compound (B) or sulfonic acid generator) is an actinic ray such as KrF excimer laser light, electron beam, EUV, etc. Or a compound that generates sulfonic acid upon irradiation with radiation, and examples thereof include diazonium salts, phosphonium salts, sulfonium salts, iodonium salts, imide sulfonates, oxime sulfonates, diazodisulfones, disulfones, and o-nitrobenzyl sulfonates. .

  Further, a group that generates an acid upon irradiation with these actinic rays or radiation, or a compound in which a compound is introduced into the main chain or side chain of the polymer, for example, US Pat. No. 3,849,137, German Patent No. 3914407. JP, 63-26653, JP, 55-164824, JP, 62-69263, JP, 63-146038, JP, 63-163452, JP, 62-153853, The compounds described in JP-A 63-146029 can be used.

  Furthermore, compounds capable of generating an acid by light described in US Pat. No. 3,779,778, European Patent 126,712 and the like can also be used.

In the present invention, examples of sulfonic acid generators that are preferable from the viewpoint of improving image performance such as resolution and pattern shape include sulfonium salts, iodonium salts, imide sulfonates, oxime sulfonates, diazodisulfones, and disulfones.
Among these, examples of particularly preferable ones are listed below.

Although content of a compound (B) is used at 5-20 mass% on the basis of the total solid of a resist composition, Preferably it is 6-18 mass%, Most preferably, it is 7-16 mass%. It is 5% by mass or more from the viewpoint of sensitivity and line width roughness, and 20% by mass or less from the viewpoint of resolution, pattern shape, and film quality. Moreover, 1 type may be used for a compound (B), and 2 or more types may be mixed and used for it. For example, as the compound (B), a compound that generates aryl sulfonic acid upon irradiation with actinic rays or radiation and a compound that generates alkyl sulfonic acid upon irradiation with actinic rays or radiation may be used in combination.
Compound (B) can be synthesized by a known method such as the synthesis method described in JP-A-2002-27806.

<Compound capable of generating carboxylic acid upon irradiation with actinic ray or radiation (C)>
The positive resist composition of the present invention includes a compound (also referred to as a compound (C) or a carboxylic acid generator) that generates a carboxylic acid upon irradiation with actinic rays or radiation together with a sulfonic acid generator (compound (B)). May be used.
As the carboxylic acid generator, a compound represented by the following general formula (C) is preferable.

In the general formula (C), R _{21 to} R ₂₃ each independently represents an alkyl group, a cycloalkyl group, an alkenyl group or an aryl group, and R ₂₄ represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group or an aryl group. Z represents a sulfur atom or an iodine atom. When Z is a sulfur atom, p is 1, and when Z is an iodine atom, p is 0.

In the general formula (C), R _{21 to} R ₂₃ each independently represents an alkyl group, a cycloalkyl group, an alkenyl group, or an aryl group, and these groups may have a substituent.
Examples of the substituent that the alkyl group, cycloalkyl group or alkenyl group may have include a halogen atom (a chlorine atom, a bromine atom, a fluorine atom, etc.), an aryl group (a phenyl group, a naphthyl group, etc.), a hydroxy group, An alkoxy group (methoxy group, ethoxy group, butoxy group, etc.) etc. can be mentioned.
Examples of the substituent that the aryl group may have include a halogen atom (chlorine atom, bromine atom, fluorine atom, etc.), nitro group, cyano group, alkyl group (methyl group, ethyl group, t-butyl group, t -Amyl group, octyl group, etc.), hydroxy group, alkoxy group (methoxy group, ethoxy group, butoxy group, etc.) and the like.

R _{21 to} R ₂₃ are preferably each independently an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, or an aryl group having 6 to 24 carbon atoms. And more preferably an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and an aryl group having 6 to 18 carbon atoms, and particularly preferably an aryl group having 6 to 15 carbon atoms. Each of these groups may have a substituent.

R ₂₄ represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group or an aryl group.
Examples of the substituent that the alkyl group, cycloalkyl group, and alkenyl group may have are the same as those described as examples of the substituent when R ₂₁ is an alkyl group. Examples of the substituent for the aryl group, the R ₂₁ may be the same as those mentioned as examples of the substituent when it is an aryl group.

R ₂₄ is preferably a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms, an aryl group having 6 to 24 carbon atoms, and more Preferably, they are a C1-C18 alkyl group, a C3-C18 cycloalkyl group, and a C6-C18 aryl group, Most preferably, a C1-C12 alkyl group, C3-C3 A cycloalkyl group having 12 carbon atoms and an aryl group having 6 to 15 carbon atoms. Each of these groups may have a substituent.

Z represents a sulfur atom or an iodine atom. p is 1 when Z is a sulfur atom, and 0 when Z is an iodine atom.
Two or more of the cation moieties of formula (C) are bonded by a single bond or a linking group (for example, -S-, -O-, etc.) to form a cation structure having a plurality of cation moieties of formula (C). May be.

  The preferred specific examples of the compound (C) that generates a carboxylic acid upon irradiation with actinic rays or radiation are shown below, but of course not limited thereto.

The content of the compound (C) in the positive resist composition of the present invention is preferably 0.01 to 10% by mass, more preferably 0.03 to 5% by mass, based on the total solid content of the composition. Particularly preferably, the content is 0.05 to 3% by mass. In addition, these compounds that generate a carboxylic acid upon irradiation with actinic rays or radiation may be used alone or in combination of two or more.
The compound (C) / compound (B) (mass ratio) is usually 99.9 / 0.1 to 50/50, preferably 99/1 to 60/40, particularly preferably 98/2 to 70/30. .
Compound (C) can be synthesized by a known method such as a synthesis method described in JP-A-2002-27806.

[3] Organic Basic Compound In the present invention, it is preferable to use an organic basic compound from the viewpoint of improving performance such as resolution and improving storage stability. As the organic basic compound, a compound containing a nitrogen atom (nitrogen-containing basic compound) is more preferable.
A preferable organic basic compound in the present invention is a compound having a stronger basicity than phenol.
As a preferable chemical environment, structures of the following formulas (A) to (E) can be exemplified. Formulas (B) to (E) may be part of a ring structure.

In the formula (A), R ²⁰⁰ , R ²⁰¹ and R ²⁰² may be the same or different and are a hydrogen atom, an alkyl group (preferably having 1 to 20 carbon atoms) or a cycloalkyl group (preferably having 3 to 20 carbon atoms). Or an aryl group (preferably having 6 to 20 carbon atoms), wherein R ²⁰¹ and R ²⁰² may be bonded to each other to form a ring.
The alkyl group, cycloalkyl group and aryl group as R ²⁰⁰ , R ²⁰¹ and R ²⁰² may have a substituent. As the alkyl group and cycloalkyl group having a substituent, an aminoalkyl group having 1 to 20 carbon atoms and an aminocycloalkyl group, and a hydroxyalkyl group having 1 to 20 carbon atoms are preferable.
In the formula (E), R ²⁰³ , R ²⁰⁴ , R ²⁰⁵ and R ²⁰⁶ may be the same or different and each represents an alkyl group having 1 to 6 carbon atoms and a cycloalkyl group.
Further preferred compounds are nitrogen-containing basic compounds having two or more nitrogen atoms of different chemical environments in one molecule, and particularly preferably both a substituted or unsubstituted amino group and a ring structure containing a nitrogen atom. Or a compound having an alkylamino group.

  Preferred examples include guanidine, aminopyridine, aminoalkylpyridine, aminopyrrolidine, indazole, imidazole, pyrazole, pyrazine, pyrimidine, purine, imidazoline, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine and the like. Preferred substituents that these may have include amino groups, alkylamino groups, aminoaryl groups, arylamino groups, alkyl groups (substituent alkyl groups, particularly aminoalkyl groups), alkoxy groups, acyl groups, and acyloxy groups. , Aryl group, aryloxy group, nitro group, hydroxyl group, cyano group and the like.

Particularly preferred compounds include guanidine, 1,1-dimethylguanidine, 1,1,3,3-tetramethylguanidine, imidazole, 2-methylimidazole, 4-methylimidazole, N-methylimidazole, 2-phenylimidazole, 4 , 5-diphenylimidazole, 2,4,5-triphenylimidazole, 2-aminopyridine, 3-aminopyridine, 4-aminopyridine, 2-dimethylaminopyridine, 4-dimethylaminopyridine, 2-diethylaminopyridine, 2- (Aminomethyl) pyridine, 2-amino-3-methylpyridine, 2-amino-4-methylpyridine, 2-amino-5-methylpyridine, 2-amino-6-methylpyridine, 3-aminoethylpyridine, 4- Aminoethylpyridine,

3-aminopyrrolidine, piperazine, N- (2-aminoethyl) piperazine, N- (2-aminoethyl) piperidine, 4-amino-2,2,6,6-tetramethylpiperidine, 4-piperidinopiperidine, 2-iminopiperidine, 1- (2-aminoethyl) pyrrolidine, pyrazole, 3-amino-5-methylpyrazole, 5-amino-3-methyl-1-p-tolylpyrazole, pyrazine, 2- (aminomethyl)- Examples include 5-methylpyrazine, pyrimidine, 2,4-diaminopyrimidine, 4,6-dihydroxypyrimidine, 2-pyrazoline, 3-pyrazoline, N-aminomorpholine, N- (2-aminoethyl) morpholine. It is not limited to this.
These nitrogen-containing basic compounds are used alone or in combination of two or more.

A tetraalkylammonium salt type nitrogen-containing basic compound can also be used. Among these, tetraalkylammonium hydroxide having 1 to 8 carbon atoms (tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetra- (
n-butyl) ammonium hydroxide and the like are preferred. These nitrogen-containing basic compounds are used alone or in combination of two or more.

The use ratio of the acid generator and the organic basic compound in the composition is preferably (total amount of acid generator) / (organic basic compound) (molar ratio) = 2.5 to 300. By setting the molar ratio to 2.5 or more, high sensitivity is obtained, and by setting the molar ratio to 300 or less, it is possible to suppress the resist pattern from becoming thicker over time until post-exposure heat treatment and improve resolution. . (Total amount of acid generator) / (organic basic compound) (molar ratio) is preferably 5.0 to 200, more preferably 7.0 to 150.

[4] Surfactants In the present invention, surfactants can be used, which are preferable from the viewpoints of film forming properties, pattern adhesion, development defect reduction, and the like.

  Specific examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether, polyoxyethylene Polyoxyethylene alkyl allyl ethers such as nonylphenol ether, polyoxyethylene / polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitan tristearate Sorbitan fatty acid esters such as rate, polyoxyethylene sorbitan monolaurate, polyoxyethylene Sorbitan mono palmitate - door,

Nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan tristearate, F-top EF301, EF303, EF352 (Shin-Akita Kasei) (Made by Co., Ltd.), MegaFuck F171, F173 (Dainippon Ink Chemical Co., Ltd.), Florad FC430, FC431 (Sumitomo 3M), Asahi Guard AG710, Surflon S-382, SC101, SC102 , SC103, SC104, SC105, SC106 (manufactured by Asahi Glass Co., Ltd.), Troysol S-366 (manufactured by Troy Chemical Co., Ltd.) and the like, or silicon-based surfactants, organosiloxane polymer KP341 Shin-Etsu Chemical Co., Ltd.) and acrylic or methacrylic acid-based (co) polymer Polyflow No. 75, no. 95 (manufactured by Kyoeisha Yushi Chemical Co., Ltd.). The compounding amount of these surfactants is usually 2 parts by mass or less, preferably 1 part by mass or less per 100 parts by mass of the solid content in the composition of the present invention.
These surfactants may be added alone or in some combination.

The surfactant is any one of fluorine and / or silicon surfactants (fluorine surfactants and silicon surfactants, surfactants containing both fluorine atoms and silicon atoms), or It is preferable to contain 2 or more types.
As these surfactants, for example, JP-A-62-36663, JP-A-61-226746, JP-A-61-226745, JP-A-62-170950, JP-A-63-34540 No. 7, JP-A-7-230165, JP-A-8-62834, JP-A-9-54432, JP-A-9-5988, JP-A 2002-277862, US Pat. No. 5,405,720. , No. 5,360,692, No. 5,529,881, No. 5,296,330, No. 5,543,098, No. 5,576,143, No. 5,294,511, No. 5,824,451. The following commercially available surfactants can also be used as they are.
Examples of commercially available surfactants that can be used include F-top EF301, EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC430, 431 (manufactured by Sumitomo 3M Co., Ltd.), MegaFuck F171, F173, F176, F189, R08 (Dainippon Ink Chemical Co., Ltd.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (Asahi Glass Co., Ltd.), Troisol S-366 (Troy Chemical Co., Ltd.), etc. Fluorine type surfactant or silicon type surfactant can be mentioned. Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used as a silicon-based surfactant.

In addition to the known surfactants described above, the surfactant is derived from a fluoroaliphatic compound produced by a telomerization method (also called telomer method) or an oligomerization method (also called oligomer method). A surfactant using a polymer having a fluoroaliphatic group can be used. The fluoroaliphatic compound can be synthesized by the method described in JP-A-2002-90991.
As the polymer having a fluoroaliphatic group, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate and / or (poly (oxyalkylene)) methacrylate is preferable and distributed irregularly. Or may be block copolymerized. Examples of the poly (oxyalkylene) group include a poly (oxyethylene) group, a poly (oxypropylene) group, a poly (oxybutylene) group, and the like, and a poly (oxyethylene, oxypropylene, and oxyethylene group). A unit having different chain lengths in the same chain length, such as a block linked body) or a poly (block linked body of oxyethylene and oxypropylene) group, may be used. Furthermore, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate (or methacrylate) is not only a binary copolymer but also a monomer having two or more different fluoroaliphatic groups, Further, it may be a ternary or higher copolymer obtained by simultaneously copolymerizing two or more different (poly (oxyalkylene)) acrylates (or methacrylates).
Examples of commercially available surfactants include Megafac F178, F-470, F-473, F-475, F-476, and F-472 (Dainippon Ink Chemical Co., Ltd.). Further, a copolymer of an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxyalkylene)) acrylate (or methacrylate), an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxy) Ethylene)) acrylate (
Or methacrylate) and (poly (oxypropylene)) acrylate (or methacrylate) copolymer, acrylate (or methacrylate) having C ₈ F ₁₇ group and (poly (oxyalkylene)) acrylate (or methacrylate). Polymer, copolymer of acrylate (or methacrylate), (poly (oxyethylene)) acrylate (or methacrylate) and (poly (oxypropylene)) acrylate (or methacrylate) having a C ₈ F ₁₇ group, and the like. be able to.

  The amount of the surfactant used is preferably 0.0001 to 2% by mass, more preferably 0.001 to 1% by mass, based on the total amount of the positive resist composition (excluding the solvent).

[5] Other components The positive resist composition of the present invention may further contain a dye, a photobase generator and the like, if necessary.

1. Dye A dye can be used in the present invention.
Suitable dyes include oily dyes and basic dyes. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (oriental chemical industry) Co., Ltd.), crystal violet (CI42555), methyl violet (CI42535), rhodamine B (CI45170B), malachite green (CI42000), methylene blue (CI522015) and the like.

2. Photobase generator As photobase generators that can be added to the composition of the present invention, JP-A-4-151156, JP-A-4-162040, JP-A-5-197148, JP-A-5-5995, JP-A-6-194835, Examples thereof include compounds described in JP-A-8-146608, JP-A-10-83079 and European Patent No. 622682, specifically, 2-nitrobenzylcarbamate, 2,5-dinitrobenzylcyclohexylcarbamate, N-cyclohexyl-4- Methylphenylsulfonamide, 1,1-dimethyl-2-phenylethyl-N-isopropylcarbamate and the like can be suitably used. These photobase generators are added for the purpose of improving the resist shape and the like.

3. Solvents The resist composition of the present invention is dissolved in a solvent that dissolves each of the above components and coated on a support. The solid content concentration of all resist components is usually preferably 2 to 30% by mass, more preferably 3 to 25% by mass.
Solvents used here include ethylene dichloride, cyclohexanone, cyclopentanone, 2-heptanone, γ-butyrolactone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, ethylene glycol monoethyl ether acetate , Propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, toluene, ethyl acetate, methyl lactate, ethyl lactate, methyl methoxypropionate, ethyl ethoxypropionate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, N, N-dimethyl Formamide, dimethyl sulfoxide, N-methylpyrrolidone, tetrahydrofuran and the like are preferable. Or mixed to use.

  The positive resist composition of the present invention is applied onto a substrate to form a thin film. The thickness of this coating film is preferably 0.05 to 4.0 μm.

  In the present invention, a commercially available inorganic or organic antireflection film can be used if necessary. Furthermore, an antireflection film can be applied to the resist lower layer and used.

  As the antireflection film used as the lower layer of the resist, either an inorganic film type such as titanium, titanium dioxide, titanium nitride, chromium oxide, carbon, amorphous silicon, or an organic film type made of a light absorber and a polymer material may be used. it can. The former requires equipment such as a vacuum deposition apparatus, a CVD apparatus, and a sputtering apparatus for film formation. Examples of the organic antireflection film include a condensate of a diphenylamine derivative and a formaldehyde-modified melamine resin described in JP-B-7-69611, an alkali-soluble resin, a light absorber, and maleic anhydride copolymer described in US Pat. No. 5,294,680. A reaction product of a coalescence and a diamine type light absorbing agent, a resin binder described in JP-A-6-186863 and a methylolmelamine thermal crosslinking agent, a carboxylic acid group, an epoxy group and a light-absorbing group described in JP-A-6-118656. An acrylic resin-type antireflection film in the same molecule, a composition comprising methylol melamine and a benzophenone-based light absorber described in JP-A-8-87115, and a low-molecular light absorber added to a polyvinyl alcohol resin described in JP-A-8-179509 And the like.

  In addition, as the organic antireflection film, commercially available organic antireflection films such as DUV30 series, DUV-40 series manufactured by Brewer Science, AR-2, AR-3, AR-5 manufactured by Shipley, etc. may be used. it can. However, since the resin containing the repeating unit represented by the general formula (1) has light absorption, an organic antireflection film need not be used.

  In the manufacture of precision integrated circuit elements, the pattern forming process on the resist film is carried out on the substrate (eg, silicon / silicon dioxide coated substrate, glass substrate, ITO substrate, quartz / chromium oxide coated substrate, etc.). A resist pattern is formed by applying a resist composition, forming a resist film, and then irradiating actinic rays or radiation such as KrF excimer laser light, electron beam, EUV light, etc., heating, developing, rinsing and drying. Can be formed.

Examples of the alkaline developer used in development include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia, and primary amines such as ethylamine and n-propylamine. Secondary amines such as diethylamine and di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcoholamines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, An aqueous solution (usually 0.1 to 20% by mass) of an alkali such as a quaternary ammonium salt such as choline or a cyclic amine such as pyrrole or piperidine can be used. In addition, an appropriate amount of an alcohol such as isopropyl alcohol or a nonionic surfactant may be added to the alkaline aqueous solution.
Among these developers, quaternary ammonium salts are preferable, and tetramethylammonium hydroxide and choline are more preferable.
The pH of the alkali developer is usually 10-15.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, the content of this invention is not limited by this.
[Synthesis Example 1: Synthesis of Specific Example A-1 of Resin (A)]
Acetoxystyrene, 1-phenylethyl methacrylate, and indenone were charged at a ratio (molar ratio) of 75/20/5, and dissolved in tetrahydrofuran to prepare 100 mL of a solution having a solid content concentration of 20% by mass. To this solution was added 2 mol% of a polymerization initiator V-65 manufactured by Wako Pure Chemical Industries, Ltd., and this was heated to 60 ° C. for 4 hours under a nitrogen atmosphere.
Added dropwise to ml. After completion of the dropwise addition, the reaction solution was heated for 4 hours, 1 mol% of V-65 was added again, and the mixture was stirred for 4 hours. After completion of the reaction, the reaction solution was cooled to room temperature, crystallized in 3 L of hexane, and the precipitated white powder was collected by filtration.
The composition ratio of the polymer determined from C ¹³ NMR was 76/21/3 (molar ratio). Moreover, the weight average molecular weight of standard polystyrene conversion calculated | required by GPC measurement was 9,500.
The polymer was dissolved in 100 ml of ethyl acetate, 5 ml of a 28% methanol solution of sodium methoxide was added and stirred for 1 hour, acidified with hydrochloric acid, and distilled water was added to precipitate the polymer. The precipitate was washed with distilled water and then dried under reduced pressure. After dissolving the polymer in 100 ml of ethyl acetate, hexane was added and the precipitated polymer was powdered by drying under reduced pressure. The weight average molecular weight in terms of standard polystyrene determined by GPC measurement for this powder was 12,000.

Resins exemplified in the structure shown in Table 1 were synthesized in the same manner as in Synthesis Example 1 above.

  The resins used in the examples of the present invention, which have increased solubility in an alkaline developer due to the action of other acids, and acid generators were both synthesized by a known synthesis method.

[Example 1]
(1) Preparation and coating of positive resist Resin A-1 0.93 g
Sulfonic acid generator B-2 0.07g
Is dissolved in 8.8 g of propylene glycol monomethyl ether acetate, 0.001 g of D-1 (see below) as an organic basic compound, and Megafac F176 (manufactured by Dainippon Ink & Chemicals, Inc.) as a surfactant. 0.001 g) (abbreviated as W-1) was added and dissolved, and the resulting solution was microfiltered with a 0.1 μm aperture membrane filter to obtain a resist solution.
This resist solution was applied onto a 6-inch silicon wafer provided with an organic antireflection film (DUV-30) having a film thickness of 60 nm using a spin coater Mark8 manufactured by Tokyo Electron, and baked at 110 ° C. for 90 seconds to obtain a film thickness of 0. A uniform film of 25 μm was obtained.

(2) Production of Positive Resist Pattern This resist film was irradiated with an electron beam using an electron beam drawing apparatus (HL750, acceleration voltage 50 KeV manufactured by Hitachi, Ltd.). After irradiation, it was baked at 110 ° C. for 90 seconds, immersed in an aqueous 2.38 mass% tetramethylammonium hydroxide (TMAH) solution for 60 seconds, rinsed with water for 30 seconds and dried. The obtained pattern was evaluated by the following method.

(2-1) Sensitivity The cross-sectional shape of the obtained pattern was observed using a scanning electron microscope (S-4300, manufactured by Hitachi, Ltd.). The minimum irradiation energy when resolving a 0.15 μm line (line: space = 1: 1) was defined as sensitivity.
(2-2) LWR (Line width roughness)
About the resist pattern obtained by carrying out similarly to the above, the line width was observed with the scanning electron microscope (S-9220 by Hitachi, Ltd.), and the fluctuation | variation (LWR) of the line width in the line width of 130 nm was observed. Using a length-measuring scanning electron microscope (SEM), the line width was detected at a plurality of positions in the measurement monitor, and the dispersion (3σ) of variations in the detected positions was used as an LWR index.
(2-3) Dense / Dense Dependence The line width of the dense pattern (line: space = 1: 1) and the line width of the isolated pattern in the 0.15 μm line pattern at the irradiation dose showing the above sensitivity are measured, and the difference between them is measured. Sparse and dense dependence.

  The results of Example 1 are shown in Table 2.

[Examples 2-7 and Comparative Examples 1-2]
Using the compounds shown in Table 2, resist preparation / coating and electron beam exposure evaluation were carried out in the same manner as in Example 1. The evaluation results are shown in Table 2.

The component (c) used in the examples, other components, and the resins used in the comparative examples are shown below.
[Organic basic compounds]
D-1: tri-n-hexylamine D-2: 2,4,6-triphenylimidazole D-3: tetra- (n-butyl) ammonium hydroxide

[Other components (surfactant)]
W-1: Fluorosurfactant, Megafac F-176 (Dainippon Ink Chemical Co., Ltd.)
W-2: Fluorine / silicone surfactant, MegaFac R08 (manufactured by Dainippon Ink & Chemicals, Inc.)
W-3: Silicon-based surfactant, siloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.)

C-1 ^* : molar composition ratio; 70/30, weight average molecular weight; 9500, dispersity; 1.88, Tg; 101 ° C.

C-2 ^* : molar composition ratio; 65/15/20, weight average molecular weight; 10500, dispersity; 1.78, Tg; 156 ° C.

  From Table 2, the positive resist composition of the present invention is more sensitive and less sensitive to LWR and density than the resist compositions of Comparative Examples 1 and 2 with respect to pattern formation by electron beam irradiation. I understand that.

Example 8
A resist film was obtained in the same manner as in Example 1, except that the sulfonic acid generator B-2 was changed to 0.030 g, and the resist was prepared and coated as shown in Table 3. The film thickness was 0.40 μm.

(3) Formation of positive pattern The obtained resist film was subjected to pattern exposure using a KrF excimer laser stepper (FPA3000EX-5 manufactured by Canon Inc., wavelength 248 nm). The post-exposure processing was performed in the same manner as in Example 1. The pattern was evaluated as follows.
(3-1) Sensitivity The cross-sectional shape of the obtained pattern was observed using a scanning electron microscope (S-4300, manufactured by Hitachi, Ltd.). The minimum irradiation energy when resolving a 0.18 μm line (line: space = 1: 1) was defined as sensitivity.
(3-2) LWR (Line width roughness)
About the resist pattern obtained by carrying out similarly to the above, the line width was observed with the scanning electron microscope (S-9220 by Hitachi, Ltd.), and the fluctuation | variation (LWR) of the line width in the line width of 130 nm was observed. Using a length-measuring scanning electron microscope (SEM), the line width was detected at a plurality of positions in the measurement monitor, and the dispersion (3σ) of variations in the detected positions was used as an LWR index.
(3-3) Density dependency The line width of the dense pattern (line: space = 1: 1) and the line width of the isolated pattern in the 0.18 μm line pattern at the irradiation dose exhibiting the above sensitivity are measured, and the difference between them is measured. Sparse and dense dependence. The evaluation results are shown in Table 3.

[Examples 9 to 14 and Comparative Examples 3 to 4]
Using the compounds shown in Table 3, resist preparation / coating and KrF excimer laser exposure evaluation were performed in the same manner as in Example 8 as described above. The evaluation results are shown in Table 3.

  From Table 3, the positive resist composition of the present invention is superior to the resist compositions of Comparative Examples 3 and 4 with respect to pattern formation by KrF excimer laser exposure, and is excellent in low LWR and density dependence. I understand that.

[Examples 15 to 23 and Comparative Examples 5 to 6]
Using each resist composition shown in Table 4, a resist film was obtained in the same manner as in Example 1. However, the resist film thickness was 0.13 μm. EUV light (wavelength 13 nm) on the resulting resist film
The surface exposure was performed while changing the exposure amount by 0.5 mJ in the range of 0 to 5.0 mJ, and further baked at 110 ° C. for 90 seconds. Thereafter, using a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution, the dissolution rate at each exposure amount was measured to obtain a sensitivity curve. In this sensitivity curve, the exposure amount when the dissolution rate of the resist is saturated was taken as sensitivity, and the dissolution contrast (γ value) was calculated from the gradient of the linear portion of the sensitivity curve. The larger the γ value, the better the dissolution contrast.
The results are shown in Table 4.

  From Table 4, it can be seen that the positive resist composition of the present invention is superior in sensitivity and high contrast as compared with the resist compositions of Comparative Examples 5 and 6 in the characteristics evaluation by irradiation with EUV light. .

Claims (7)

(A) a resin having a repeating unit represented by the general formula (1), which decomposes by the action of an acid and increases alkali solubility, and (B) a compound that generates an acid upon irradiation with actinic rays or radiation. A resist composition containing the resist composition.

(1)
In general formula (1),
R ¹ represents a hydroxyl group, an alkyl group, a cycloalkyl group, an alkoxy group, a hydroxyl group substituted by an acid labile group, a cyano group, a carboxyl group substituted by an acid labile group, or a halogen atom, and a plurality thereof Sometimes they can be the same or different. x represents an integer of 0 to 2, and y represents an integer of 0 to 4. Resin (A) contains the repeating unit further represented by General formula (2), The resist composition of Claim 1 characterized by the above-mentioned.

(2)

In general formula (2),
AR represents an aromatic ring.
Rn represents an alkyl group, a cycloalkyl group or an aryl group.
AR and Rn may be bonded to each other to form a ring.
A represents a hydrogen atom, an alkyl group, a halogen atom, a cyano group, or an alkyloxycarbonyl group. Resin (A) contains the repeating unit further represented by General formula (3), The resist composition of Claim 1 or 2 characterized by the above-mentioned.

(3)
In general formula (3),
n represents an integer of 0 to 3. m shows the integer of 0-3. However, m + n ≦ 5.
A ₁ represents a hydrogen atom or a group containing a group that decomposes under the action of an acid, and when there are a plurality of groups, they may be the same or different.
S ₁ represents an arbitrary substituent, and when there are a plurality of them, they may be the same or different.
R ₅ represents a hydrogen atom, an alkyl group, a halogen atom, a cyano group, or an alkyloxycarbonyl group.   Furthermore, the organic solvent is contained, The resist composition in any one of Claims 1-3 characterized by the above-mentioned.   Furthermore, a basic compound is contained, The resist composition of Claim 4 characterized by the above-mentioned. A pattern forming method comprising: forming a resist film from the resist composition according to claim 1, exposing and developing the resist film. A resin having a weight average molecular weight of 1,000 to 50,000, having a repeating unit represented by the general formula (1) and a repeating unit containing an acid-decomposable group.

(1)
In general formula (1),
R ¹ represents a hydroxyl group, an alkyl group, a cycloalkyl group, an alkoxy group, a hydroxyl group substituted by an acid labile group, a cyano group, a carboxyl group substituted by an acid labile group, or a halogen atom.
x represents an integer of 0 to 2, and y represents an integer of 0 to 4.