JP2005084238A - Positive resist composition and method for forming pattern by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive resist composition suitable for the use of an exposure light source at ≤160 nm, in particular, F<SB>2</SB>excimer laser light (at 157 nm), and specifically, to provide a positive resist composition which suppresses development defects, and to provide a method for forming a pattern by using the composition. <P>SOLUTION: The positive resist composition contains: (A) a fluorine-containing resin which has such a structure that a fluorine atom is introduced by substitution in the main chain of the polymer skeleton, which has a group expressed by a specified structure and which is decomposable by the effect of an acid to increase the solubility with an alkaline developing solution; (B) a compound which generates an acid by irradiation with active rays; and (C) at least two basic compounds. The method for forming a pattern is carried out by using the composition. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a positive resist composition suitably used in microlithography processes such as the production of VLSI and high-capacity microchips, and other photofabrication processes. More specifically, the present invention relates to a positive resist composition capable of forming a highly refined pattern using vacuum ultraviolet light of 160 nm or less and a pattern forming method using the same.

  Integrated circuits have been increasingly integrated, and in manufacturing semiconductor substrates such as VLSI, processing of ultrafine patterns having a line width of less than a quarter micron has been required. As one of means for miniaturizing a pattern, it is known to shorten the wavelength of an exposure light source used in forming a resist pattern.

For example, in the manufacture of a semiconductor device having a degree of integration of up to 64 Mbits, i-line (365 nm) of a high-pressure mercury lamp has been used as a light source until now. As a positive resist corresponding to this light source, a number of compositions containing a novolak resin and a naphthoquinonediazide compound as a photosensitive material have been developed, and have achieved sufficient results in processing line widths of up to about 0.3 μm. . Further, in the manufacture of a semiconductor device having an integration degree of 256 Mbit or more, KrF excimer laser light (248 nm) has been adopted as an exposure light source instead of i-line.
Furthermore, for the purpose of manufacturing semiconductors with a degree of integration of 1 Gbit or more, the use of ArF excimer laser light (193 nm), which is a light source with a shorter wavelength in recent years, and further F ₂ excimer laser light to form a pattern of 0.1 μm or less. The use of (157 nm) is under consideration.

In accordance with the shortening of the wavelength of these light sources, the constituent components of the resist material and the compound structure thereof have also changed greatly. That is, in the conventional resist containing novolak resin and naphthoquinonediazide compound, since absorption in the far ultraviolet region of 248 nm is large, it becomes difficult for light to reach the bottom of the resist sufficiently, and only a taper-shaped pattern with low sensitivity can be obtained.
In order to solve such a problem, a compound that generates an acid by irradiation with far ultraviolet light using, as a main component, a resin having a poly (hydroxystyrene) having a low absorption in the 248 nm region as a basic skeleton and protected by an acid-decomposable group ( A composition combining a photoacid generator), a so-called chemically amplified resist, has been developed. Since the chemically amplified resist changes the solubility in the developer by the catalytic decomposition reaction of the acid generated in the exposed area, a highly sensitive and high resolution pattern can be formed.

  However, when ArF excimer laser light (193 nm) is used, since the compound having an aromatic group essentially has a large absorption in the 193 nm wavelength region, sufficient performance was not obtained even with the above chemically amplified resist.

  To solve this problem, an acid-decomposable resin having poly (hydroxystyrene) as a basic skeleton is replaced with an acid-decomposable resin in which an alicyclic structure having no absorption at 193 nm is introduced into the main chain or side chain of the polymer. Improvement of the amplification type resist is attempted.

However, for F ₂ excimer laser light (157 nm), it was found that the alicyclic resin also has a large absorption in the 157 nm region, which is insufficient to obtain the desired pattern of 0.1 μm or less. . In contrast, Non-Patent Document 1 (Proc. SPIE. Vol. 3678. p. 13 (1999)) reports that a resin into which a fluorine atom (perfluoro structure) is introduced has sufficient transparency at 157 nm. Non-Patent Document 2 (Proc. SPIE. Vol. 3999. 330 (2000)), Non-Patent Document 3 (357 (2000)), Non-Patent Document 4 (365 (2000)) )), Patent Document 1 (WO-00 / 17712A2) and the like.
However, resists having these fluororesins have been desired to suppress development defects because of their unique water and oil repellency properties derived from the perfluoro structure.

Proc. SPIE., 1999, Vol. 3678, p.13 Proc. SPIE., 2000, Vol. 3999, p. 330 Proc. SPIE., 2000, Vol. 3999, p. 357 Proc. SPIE., 2000, Vol. 3999. 365 pages International Publication No. 00/17712 Pamphlet

Accordingly, an object of the present invention is to provide a positive resist composition suitable for use with an exposure light source of 160 nm or less, particularly F ₂ excimer laser light (157 nm), and specifically reduces the occurrence of development defects. The present invention provides a positive resist composition and a pattern forming method using the same.

As a result of intensive investigations while paying attention to the above characteristics, the present inventors have found that the object of the present invention can be achieved brilliantly by using the following specific composition, and have reached the present invention.
That is, the present invention has the following configuration.

(1) (A) a fluorine-containing resin having a structure in which a fluorine atom is substituted in the main chain of the polymer skeleton, which is decomposed by the action of an acid and has increased solubility in an alkali developer;
(B) a compound that generates an acid upon irradiation with actinic rays, and
(C) A positive resist composition containing at least two types of basic compounds.

  (2) The weight average molecular weight of the resin (A) is 1,000 to 200,000, and the content of a component having a molecular weight of 1,000 or less in the resin (A) is 10% by mass or less. A positive resist composition.

  (3) The resin (A) is a repeating unit represented by the following general formulas (IV) to (IX) and at least one selected from the group of repeating units represented by the following general formulas (I) to (III) The positive resist composition as described in (1) or (2) above, which is a resin having at least one selected from the group of units.

In general formulas (I) to (IX),
R ₀ and R ₁ may be the same or different and each represents a hydrogen atom, a fluorine atom, an alkyl group, a cycloalkyl group, or an aryl group.
R _{2 to} R ₄ may be the same or different and each represents an alkyl group, a cycloalkyl group, or an aryl group.
R ₀ and R ₁ , R ₀ and R ₂ , R ₃ and R ₄ may combine to form a ring.
R ₅ represents an alkyl group, a cycloalkyl group, an acyl group, or an alkoxycarbonyl group.
R ₆ , R ₇ and R ₈ may be the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group.
R ₉ and R ₁₀ represent a hydrogen atom, a halogen atom, a cyano group or an alkyl group.
R ₁₁ and R ₁₂ may be the same or different and each represents a hydrogen atom, a hydroxyl group, a halogen atom, a cyano group, an alkoxy group, an acyl group, an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group, or an aryl group. .
R ₁₃ and R ₁₄ may be the same or different and each represents a hydrogen atom, a halogen atom, a cyano group or an alkyl group.
R ₁₅ represents —C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), —C (R ₃₆ ) (R ₃₇ ) (OR ₃₉ ) or a group represented by the following general formula (XIV).

R ₃₆ , R ₃₇ , R ₃₈ and R ₃₉ may be the same or different and each represents an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group. Two of R ₃₆ , R ₃₇ and R ₃₈ , or two of R ₃₆ , R ₃₇ and R ₃₉ may be bonded to form a ring.
R ₄₀ represents an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aralkyl group or an aryl group.
Z represents an atomic group constituting a monocyclic or polycyclic alicyclic group together with a carbon atom.
R ₁₆ , R ₁₇ and R ₁₈ may be the same or different and each represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an alkoxy group or —CO—O—R ₁₅ .
A ₁ and A ₂ are a single bond, an alkylene group, an alkenylene group, a cycloalkylene group, an arylene group, a divalent alicyclic group, a divalent linking group formed by combining two or more thereof, or —O—CO—R. _22- , -CO-O-R _23- , -CO-N (R ₂₄ ) -R ₂₅ -are represented.
R ₂₂ , R ₂₃ and R ₂₅ represent a single bond or an alkylene group, an alkenylene group, a cycloalkylene group or an arylene group which may have an ether group, an ester group, an amide group, a urethane group or a ureido group. .
R ₂₄ represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aralkyl group or an aryl group.
n represents 0 or 1, and m represents 1 or 2.

(4) A pattern forming method comprising: forming a resist film from the positive resist composition according to any one of (1) to (3) above; and exposing and developing the resist film.

  The present invention can provide an excellent positive resist composition having a very small number of development defects and a pattern forming method using the same.

Hereinafter, 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).

[1] Fluorine-containing resin (A)
The positive resist composition of the present invention contains a fluorine-containing resin (A) that has a structure in which a fluorine atom is substituted on the main chain of the polymer skeleton, decomposes by the action of an acid, and increases the solubility in an alkali developer. To do.

  The resin (A) used in the present invention has a group represented by the following general formula (1), and is a group that decomposes by the action of an acid and increases the solubility in an alkali developer. ) Or a resin having a tertiary ester of a carboxylic acid as a group which is decomposed by the action of an acid to increase the solubility in an alkaline developer.

In general formula (1),
R ^{a to} R ^f may be the same or different and each represents a fluorine atom or a hydrogen atom. However, at least one of R ^{a to} R ^f is a fluorine atom. One of R ^{a to} R ^f may be connected to the main chain of the resin (A) as a single bond or a carbon chain.
L represents a group that is decomposed by the action of an acid.

In the general formula (1), one of R ^{a to} R ^f may be a single bond or a carbon chain and may be connected to the main chain of the fluorine-containing resin. Such a carbon chain is preferably an alkylene group having 1 to 10 carbon atoms, and examples thereof include a methylene group, an ethylene group, a propylene group, a butylene group, a hexylene group, and an octylene group.
The group that decomposes by the action of an acid of L is a group that decomposes by the action of an acid and generates a group (hydroxyl group) that is soluble in an alkaline developer. The presence of this group causes the resin (A) to react with the action of an acid. It has the property of increasing the solubility in an alkali developer.
In the general formula (1), examples of the group capable of decomposing by the action of an acid of L include, for example, —C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), —C (R ₀₁ ) (R ₀₂ ) (OR _{39), - C (R 36} ) (R 37) ( can be exemplified OR ₃₉₎ or the like.
The group represented by the general formula (1) can be provided, for example, in the repeating units represented by the general formulas (IV) to (VII).
R ₃₆ , R ₃₇ , R ₃₈ and R ₃₉ may be the same or different and each represents an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group. Two of R ₃₆ , R ₃₇ and R ₃₈ , or two of R ₃₆ , R ₃₇ and R ₃₉ may be bonded to form a ring.
R ₀₁ and R ₀₂ represent a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group, or an aryl group.
Preferable specific examples include t-butyl group, t-amyl group, 1-alkyl-1-cyclohexyl group, 2-alkyl-2-adamantyl group, 2-adamantyl-2-propyl group, 2- (4-methylcyclohexyl). ) Ether group or ester group of tertiary alkyl group such as 2-propyl group, acetal group or acetal ester group such as 1-alkoxy-1-ethoxy group, tetrahydropyranyl group, t-alkyl carbonate group, t-alkyl Examples thereof include a carbonylmethoxy group.

In particular, the resin (A) includes at least one selected from the group of repeating units represented by the following general formulas (I) to (III) and a repeating unit represented by the following general formulas (IV) to (IX). It is preferable that it is resin which has at least 1 sort (s) chosen from these groups.
The repeating units represented by the following general formulas (IV) to (VII) are repeating units having a group represented by the above general formula (1), and are represented by the following general formulas (VIII) to (IX). The repeating unit is a repeating unit having a tertiary ester of a carboxylic acid as a group that decomposes by the action of an acid and increases the solubility in an alkaline developer.

In general formulas (I) to (IX),
R ₀ and R ₁ may be the same or different and each represents a hydrogen atom, a fluorine atom, an alkyl group, a cycloalkyl group, or an aryl group.
R _{2 to} R ₄ may be the same or different and each represents an alkyl group, a cycloalkyl group, or an aryl group.
R ₀ and R ₁ , R ₀ and R ₂ , R ₃ and R ₄ may combine to form a ring.
R ₅ represents an alkyl group, a cycloalkyl group, an acyl group, or an alkoxycarbonyl group.
R ₆ , R ₇ and R ₈ may be the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group.
R ₉ and R ₁₀ represent a hydrogen atom, a halogen atom, a cyano group or an alkyl group.
R ₁₁ and R ₁₂ may be the same or different and each represents a hydrogen atom, a hydroxyl group, a halogen atom, a cyano group, an alkoxy group, an acyl group, an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group, or an aryl group. .
R ₁₃ and R ₁₄ may be the same or different and each represents a hydrogen atom, a halogen atom, a cyano group or an alkyl group.
R ₁₅ represents —C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), —C (R ₃₆ ) (R ₃₇ ) (OR ₃₉ ) or a group represented by the following general formula (XIV).

R ₃₆ , R ₃₇ , R ₃₈ and R ₃₉ may be the same or different and each represents an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group. Two of R ₃₆ , R ₃₇ and R ₃₈ , or two of R ₃₆ , R ₃₇ and R ₃₉ may be bonded to form a ring.
R ₄₀ represents an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aralkyl group or an aryl group.
Z represents an atomic group constituting a monocyclic or polycyclic alicyclic group together with a carbon atom.
R ₁₆ , R ₁₇ and R ₁₈ may be the same or different and each represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an alkoxy group or —CO—O—R ₁₅ .
A ₁ and A ₂ are a single bond, an alkylene group, an alkenylene group, a cycloalkylene group, an arylene group, a divalent alicyclic group, a divalent linking group formed by combining two or more thereof, or —O—CO—R. _22- , -CO-O-R _23- , -CO-N (R ₂₄ ) -R ₂₅ -are represented.
R ₂₂ , R ₂₃ and R ₂₅ represent a single bond or an alkylene group, an alkenylene group, a cycloalkylene group or an arylene group, which may have an ether group, an ester group, an amide group, a urethane group or a ureido group.
R ₂₄ represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aralkyl group or an aryl group.
n represents 0 or 1, and m represents 1 or 2.

In general formulas (I) to (IX),
The alkyl group may have a substituent, for example, an alkyl group having 1 to 12 carbon atoms, specifically, a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group. Preferred examples include a group, t-butyl group, hexyl group, and octyl group.
Examples of the alkyl group having a substituent include a haloalkyl group, a hydroxyalkyl group, and an alkoxyalkyl group.
Preferred examples of the haloalkyl group include a perfluoroalkyl group, a chloromethyl group, a chloroethyl group, a chloropropyl group, a chlorobutyl group, a bromomethyl group, and a bromoethyl group. Of these, a perfluoroalkyl group is more preferable, and examples thereof include a perfluorobutyl group, a perfluorohexyl group, a perfluorooctyl group, a perfluorooctylethyl group, and a perfluorododecyl group.
As a hydroxyalkyl group, a C1-C8 hydroxyalkyl group is preferable, for example, a hydroxymethyl group, a hydroxyethyl group, a hydroxypropyl group, a hydroxybutyl group, a hydroxypentyl group etc. can be mentioned.
The alkoxyalkyl group may have a substituent, and examples thereof include a group in which an alkoxy group described later is substituted with an alkyl group. As the alkoxyalkyl group, an alkoxymethyl group which may have a substituent is preferable.

  The cycloalkyl group may have a substituent and may be monocyclic or polycyclic. Examples of the monocyclic type include those having 3 to 8 carbon atoms, and preferred examples include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the polycyclic type include those having 6 to 20 carbon atoms, such as an adamantyl group, norbornyl group, isobornyl group, campanyl group, dicyclopentyl group, α-pinel group, tricyclodecanyl group, and tetocyclododecyl group. Preferred examples include an androstanyl group. However, the carbon atom in the monocyclic or polycyclic cycloalkyl group may be substituted with a heteroatom such as an oxygen atom.

The aryl group may have a substituent, for example, an aryl group having 6 to 15 carbon atoms, such as a phenyl group, a tolyl group, a dimethylphenyl group, a 2,4,6-trimethylphenyl group, a naphthyl group. , Anthryl group, 9,10-dimethoxyanthryl group and the like can be preferably exemplified.
The aralkyl group may have a substituent, for example, an aralkyl group having 7 to 12 carbon atoms, and preferred examples include a benzyl group, a phenethyl group, and a naphthylmethyl group.
The alkenyl group may have a substituent, for example, an alkenyl group having 2 to 8 carbon atoms, and preferred examples include a vinyl group, an allyl group, a butenyl group, and a cyclohexenyl group.

  The alkoxy group may have a substituent, for example, an alkoxy group having 1 to 8 carbon atoms, specifically, a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, a butoxy group. Preferred examples include a group, a pentoxy group, an allyloxy group, an octoxy group and the like.

The acyl group may have a substituent, for example, an acyl group having 1 to 10 carbon atoms, specifically, formyl group, acetyl group, propanoyl group, butanoyl group, pivaloyl group, octanoyl group. Preferred examples include benzoyl group.
The alkynyl group may have a substituent and is preferably an alkynyl group having 2 to 5 carbon atoms, and examples thereof include an ethynyl group, a propynyl group, and a butynyl group.
The alkoxycarbonyl group may have a substituent, i-propoxycarbonyl group, t-butoxycarbonyl group, t-amyloxycarbonyl group, 1-methyl-1-cyclohexyloxycarbonyl group, etc., preferably secondary More preferred is a tertiary alkoxycarbonyl group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

As an alkylene group, you may have a substituent, Preferably a C1-C8 thing, such as a methylene group, ethylene group, a propylene group, a butylene group, a hexylene group, an octylene group, is mentioned.
The alkenylene group may have a substituent, and preferably an alkenylene group having 2 to 6 carbon atoms such as an ethenylene group, a propenylene group, or a butenylene group.

The cycloalkylene group may have a substituent, and examples thereof include those having 5 to 8 carbon atoms such as a cyclopentylene group and a cyclohexylene group.
The arylene group may have a substituent, and examples thereof include those having 6 to 15 carbon atoms such as a phenylene group, a tolylene group, and a naphthylene group.
The divalent alicyclic group may have a substituent and may have any polycyclic structure such as bicyclo, tricyclo, and tetracyclo. The carbon number is preferably 6-30, and more preferably 7-25. Preferred examples of the divalent alicyclic group include, for example, an adamantane residue (residue obtained by removing two hydrogen atoms from adamantane, the same shall apply hereinafter), a noradamantane residue, a decalin residue, a tricyclodecane residue, tetra A cyclododecane residue, a norbornane residue, etc. can be mentioned. More preferable examples of the divalent alicyclic group include an adamantane residue and a norbornane residue.

The ring formed by combining R ₀ and R ₁ , R ₀ and R ₂ , R ₃ and R ₄ is, for example, a 5- to 7-membered ring, specifically, a pentane ring substituted with fluorine, a hexane ring, Examples include a furan ring, a dioxonol ring, and a 1,3-dioxolane ring.
The ring formed by combining two of R _{36 to} R ₃₈ or two of R _{36 to} R ₃₇ and R ₃₉ is, for example, a 3- to 8-membered ring, specifically a cyclopropane ring. , Cyclopentane ring, cyclohexane ring, furan ring, pyran ring and the like.

  Z represents an atomic group constituting a monocyclic or polycyclic alicyclic group, and the formed alicyclic group is, for example, a monocyclic type having 3 to 8 carbon atoms, and a cyclopropyl group , A cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the polycyclic type include those having 6 to 20 carbon atoms, such as an adamantyl group, a norbornyl group, an isobornyl group, a campanyl group, a dicyclopentyl group, an α-pinel group, a tricyclodecanyl group, a tetocyclododecyl group, An androstanyl group etc. can be mentioned preferably.

Alkyl group, cycloalkyl group, aryl group, aralkyl group, alkenyl group, alkoxy group, acyl group, alkynyl group, alkoxycarbonyl group, alkylene group, alkenylene group, cycloalkylene group, arylene group, divalent alicyclic group Examples of the substituent that may be present include those having active hydrogen such as cycloalkyl group, aryl group, amino group, amide group, ureido group, urethane group, hydroxyl group and carboxyl group, and halogen atoms (Fluorine atom, chlorine atom, bromine atom, iodine atom), alkoxy group (methoxy group, ethoxy group, propoxy group, butoxy group, etc.), thioether group, acyl group (acetyl group, propanoyl group, benzoyl group, etc.), acyloxy group (Acetoxy group, propanoyloxy group, benzoyloxy group, etc.), al Alkoxycarbonyl group (methoxycarbonyl group, ethoxycarbonyl group, propoxycarbonyl group), a cyano group and a nitro group.

Here, examples of the alkyl group, cycloalkyl group, and aryl group include those described above. The alkyl group may be further substituted with a fluorine atom or a cycloalkyl group.

In addition to the group represented by the general formula (1), the resin (A) may have a group (acid-decomposable group) that increases the solubility in an alkali developer by the action of an acid. Examples of such an acid-decomposable group include —O—C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), —O—C (R ₀₁ ) (R ₀₂ ) (OR ₃₉ ), —O—C ( R ₃₆ ) (R ₃₇ ) (OR ₃₉ ), —O—COO—C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), —O—C (R ₀₁ ) (R ₀₂ ) COO—C (R ₃₆ ) _{(R 37) (R 38)} , - COO-C (R 36) (R 37) (R 38), - COO-C (R 36) (R 37) (OR 39) , and the like.
R _{36 to} R ₃₉ , R ₀₁ and R ₀₂ are as defined above.

  Preferable specific examples include t-butyl group, t-amyl group, 1-alkyl-1-cyclohexyl group, 2-alkyl-2-adamantyl group, 2-adamantyl-2-propyl group, 2- (4-methylcyclohexyl). ) Ether group or ester group of tertiary alkyl group such as 2-propyl group, acetal group or acetal ester group such as 1-alkoxy-1-ethoxy group, tetrahydropyranyl group, t-alkyl carbonate group, t-alkyl Examples thereof include a carbonylmethoxy group.

  The group that decomposes by the action of an acid and increases the solubility in an alkaline developer can be given, for example, in the repeating units represented by the general formulas (IV) to (IX). It can also be included.

The group that decomposes by the action of an acid and increases the solubility in an alkaline developer can be formed, for example, as an -OL group in the general formula (1).
In the general formula (1), examples of the group capable of decomposing by the action of the acid of L include the aforementioned -C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), -C (R ₀₁ ) (R ₀₂ ). (OR ₃₉ ), —C (R ₃₆ ) (R ₃₇ ) (OR ₃₉ ) and the like can be mentioned.
The group represented by the general formula (1) can be provided, for example, in the repeating units represented by the general formulas (IV) to (VII).

A group that decomposes under the action of an acid and increases the solubility in an alkaline developer can be formed, for example, as a tertiary ester of a carboxylic acid.
The tertiary ester of carboxylic acid can be formed, for example, as a —CO—O—R ₁₅ group in the general formulas (VIII) and (IX).

The content of the repeating unit having a group represented by the general formula (1) is generally 10 to 80 mol%, preferably 30 to 70 mol%, based on all repeating units constituting the resin (A). Preferably it is used in the range of 35-65 mol%.
The total content of the repeating units represented by the general formulas (I) to (VII) is generally 10 to 80 mol%, preferably 30 to 70 mol%, more preferably 35 to 35 mol%, based on all repeating units. Used in the range of 65 mol%.

  In the resin of (A) having at least one repeating unit represented by the general formulas (I) to (III) and at least one repeating unit represented by the general formulas (IV) to (VII), The total content of the repeating units represented by the general formulas (I) to (III) is generally 5 to 70 mol%, preferably 10 to 60 mol%, more preferably 20 to 20%, based on all repeating units. It is used in the range of 50 mol%. The total content of the repeating units represented by formulas (IV) to (VII) is generally 10 to 80 mol%, preferably 30 to 70 mol%, more preferably 35 to 35 mol%, based on all repeating units. Used in the range of 65 mol%.

  In a resin having at least one repeating unit represented by general formulas (I) to (III) and at least one repeating unit represented by general formulas (VIII) to (IX), general formula (I ) To (III), the total content of the repeating units is generally in the range of 10 to 80 mol%, preferably 30 to 70 mol%, more preferably 35 to 65 mol% in the total polymer composition. Used in. The total content of the repeating units represented by the general formulas (VIII) to (IX) is generally 10 to 70 mol%, preferably 10 to 60 mol%, more preferably 20 to 50 in the total polymer composition. Used in the mol% range.

In addition to the above repeating structural units, the resin (A) of the present invention may be copolymerized with other polymerizable monomers for the purpose of further improving the performance of the positive resist of the present invention.
Examples of copolymerizable monomers that can be used include those shown below. For example, an addition polymerizable unsaturated bond selected from acrylic acid esters, acrylamides, methacrylic acid esters, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, styrenes, crotonic acid esters other than the above. A compound having one.

  Specifically, for example, acrylic acid esters, for example, alkyl (the alkyl group preferably has 1 to 10 carbon atoms) acrylate (for example, methyl acrylate, ethyl acrylate, propyl acrylate, t-butyl acrylate) Amyl acrylate, ethyl hexyl acrylate, octyl acrylate, tert-octyl acrylate, chloroethyl acrylate, 2-hydroxyethyl acrylate 2,2-dimethylhydroxypropyl acrylate, 5-hydroxypentyl acrylate, trimethylolpropane monoacrylate, Pentaerythritol monoacrylate, glycidyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, etc.) aryl acrylate (eg, phenyl acrylate);

Methacrylic acid esters, for example, alkyl (the alkyl group preferably has 1 to 10 carbon atoms) methacrylate (for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, t-butyl methacrylate, amyl methacrylate, hexyl methacrylate) Octyl methacrylate, 2-hydroxyethyl methacrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl methacrylate, 2,2-dimethyl-3-hydroxypropyl methacrylate, trimethylolpropane monomethacrylate, pentaerythritol monomethacrylate, glycidyl methacrylate, furfuryl Methacrylate, tetrahydrofurfuryl methacrylate, etc.), arylmetac Rate (e.g., phenyl methacrylate, cresyl methacrylate, naphthyl methacrylate, etc.);

Acrylamides, for example, acrylamide, N-alkyl acrylamide, (the alkyl group having 1 to 10 carbon atoms, for example, methyl group, ethyl group, propyl group, butyl group, t-butyl group, heptyl group, octyl Group, hydroxyethyl group, etc.), N-arylacrylamide (the aryl group includes, for example, phenyl group, tolyl group, nitrophenyl group, naphthyl group, cyanophenyl group, hydroxyphenyl group, carboxyphenyl group and the like. ), N, N-dialkylacrylamide (alkyl groups include those having 1 to 10 carbon atoms, such as methyl, ethyl, butyl, isobutyl, and ethylhexyl groups), N, N-diaryl. Acrylamide (Aryl group includes, for example, phenyl group ), N- methyl -N- phenyl acrylamide, N- hydroxyethyl -N- methylacrylamide, etc. N-2- acetamidoethyl -N- acetyl acrylamide;

Methacrylamide, for example, methacrylamide, N-alkylmethacrylamide (alkyl groups having 1 to 10 carbon atoms such as methyl, ethyl, t-butyl, ethylhexyl, hydroxyethyl, etc.) N-aryl methacrylamide (the aryl group includes a phenyl group), N, N-dialkyl methacrylamide (the alkyl group includes an ethyl group, a propyl group, a butyl group, etc.), N, N-diarylmethacrylamide (the aryl group includes a phenyl group), N-hydroxyethyl-N-methylmethacrylamide, N-methyl-N-phenylmethacrylamide, N-ethyl-N-phenylmethacrylate Amides; allyl compounds such as allyl esters (eg acetic acid) Lil, allyl caproate, allyl caprylate, allyl laurate, allyl palmitate, allyl stearate, allyl benzoate, allyl acetoacetate, allyl lactate, etc.), and allyl oxyethanol;

Vinyl ethers such as alkyl vinyl ethers (eg hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, ethyl hexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, chloroethyl vinyl ether, 1-methyl-2,2-dimethylpropyl vinyl ether, 2-ethylbutyl Vinyl ether, hydroxyethyl vinyl ether, diethylene glycol vinyl ether, dimethylaminoethyl vinyl ether, diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl vinyl ether, tetrahydrofurfuryl vinyl ether, etc., vinyl aryl ethers (for example, vinyl phenyl ether, vinyl tolyl ether, vinyl chloropheny) Ether, vinyl 2,4-dichlorophenyl ether, vinyl naphthyl ether, vinyl anthranyl ether);

Vinyl esters such as vinyl butyrate, vinyl isobutyrate, vinyl trimethyl acetate, vinyl diethyl acetate, vinyl valate, vinyl caproate, vinyl chloroacetate, vinyl dichloroacetate, vinyl methoxyacetate, vinyl butoxyacetate, vinylphenyl Acetate, vinyl acetoacetate, vinyl lactate, vinyl-β-phenylbutyrate, vinyl cyclohexyl carboxylate, vinyl benzoate, vinyl salicylate, vinyl chlorobenzoate, vinyl tetrachlorobenzoate, vinyl naphthoate, etc .;

Styrenes such as styrene, alkyl styrene (eg methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, isopropyl styrene, butyl styrene, hexyl styrene, decyl styrene, chloromethyl styrene, trifluoromethyl styrene, ethoxymethyl Styrene, acetoxymethylstyrene, etc.), alkoxystyrene (eg, methoxystyrene, 4-methoxy-3-methylstyrene, dimethoxystyrene, etc.), halogen styrene (eg, chlorostyrene, dichlorostyrene, trichlorostyrene, tetrachlorostyrene, penta) Chlorstyrene, bromostyrene, dibromostyrene, iodostyrene, fluorostyrene, trifluorostyrene, 2-bromo-4-triflu Methyl styrene, 4-fluoro-3-trifluoromethyl styrene etc.), carboxy styrene, vinyl naphthalene;

Crotonic esters such as alkyl crotonic acid (eg butyl crotonate, hexyl crotonate, glycerol monocrotonate); dialkyl itaconates (eg dimethyl itaconate, diethyl itaconate, dibutyl itaconate); Examples thereof include dialkyl esters of acid or fumaric acid (for example, dimethyl maleate and dibutyl fumarate), maleic anhydride, maleimide, acrylonitrile, methacrylonitrile, maleilonitrile and the like. In addition, any addition-polymerizable unsaturated compound that is generally copolymerizable may be used.

  Specific examples of the repeating structural unit represented by the general formulas (I) to (IX) are shown below, but the present invention is not limited thereto.

  Hereinafter, although the specific example of resin (A) is shown, this invention is not limited to this.

  Each of the repeating structural units represented by the above general formula may be used alone or in combination.

  The molecular weight of the resin (A) is preferably 1,000 to 200,000, more preferably 3,000 to 20,000, in terms of weight average. The dispersity (Mw / Mn) is usually 1 to 10, preferably 1 to 3, and more preferably 1 to 2. The smaller the degree of dispersion, the smoother the resolution, resist shape, and resist pattern side walls, and the better the roughness.

In the resin (A), since development defects are further improved, the content of a component having a molecular weight of 1000 or less is reduced to 15% by mass, preferably 10% by mass or less, and more preferably 8% by mass or less. preferable.
Reduction of the low molecular weight component can be performed by a fractionation treatment in which the resin obtained by the polymerization reaction is dissolved in a good solvent, and then the poor solvent is added to precipitate the high molecular weight component of the resin.

  The addition amount of the resin (A) is generally 50 to 99.9% by mass, preferably 60 to 98% by mass, more preferably 65 to 95% by mass, based on the total solid content of the composition. Is done.

[2] (B) Compound that generates acid upon irradiation with actinic ray Compound used for positive resist composition of the present invention that generates acid upon irradiation with actinic ray (hereinafter sometimes referred to as “acid generator”). Will be described below.
Acid generators that can be used in the present invention include photoinitiators for photocationic polymerization, photoinitiators for photoradical polymerization, photodecolorants for dyes, photochromic agents, and microresists. Known compounds that generate an acid upon irradiation with actinic rays such as far ultraviolet rays and mixtures thereof can be appropriately selected and used.

  For example, diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, onium salts such as arsonium salts, organic halogen compounds, organic metal / organic halides, acid generators having o-nitrobenzyl type protecting groups And compounds capable of generating sulfonic acid by photolysis represented by imino sulfonate and the like, and disulfone compounds.

  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, JP 63- The compounds described in No. 146029 and the like 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.

  Of the above compounds that can be decomposed by irradiation with actinic rays to generate an acid, those that are particularly effectively used will be described below.

  (1) An iodonium salt represented by the following general formula (PAG1) or a sulfonium salt represented by the general formula (PAG2).

Ar ¹ and Ar ² each independently represents an aryl group.
The aryl group as Ar ¹ and Ar ² may have a substituent, and preferred substituents include an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, a nitro group, a carboxyl group, an alkoxycarbonyl group, Examples include a hydroxy group, a mercapto group, and a halogen atom.

R ¹⁰⁰ , R ¹⁰¹ and R ¹⁰² each independently represents an alkyl group, a cycloalkyl group or an aryl group. Preferably, a C6-C14 aryl group, a C1-C8 alkyl group, and a C3-C8 cycloalkyl group can be mentioned.
The alkyl group, cycloalkyl group or aryl group as R ¹⁰⁰ , R ¹⁰¹ and R ¹⁰² may have a substituent, and preferred substituents are alkoxy having 1 to 8 carbon atoms for the aryl group. Group, an alkyl group having 1 to 8 carbon atoms, a nitro group, a carboxyl group, a hydroxy group, and a halogen atom, and an alkyl group and a cycloalkyl group having 1 to 8 carbon atoms, an alkoxy group, a carboxyl group, and alkoxycarbonyl. It is a group.

Z ⁻ represents a counter anion, such as perfluoroalkanesulfonic acid anion such as BF ₄ ⁻ , AsF ₆ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , SiF ₆ ²⁻ , ClO ₄ ⁻ , CF ₃ SO ₃ ⁻ , pentafluoro Examples include, but are not limited to, condensed polynuclear aromatic sulfonate anions such as benzenesulfonate anion and naphthalene-1-sulfonate anion, anthraquinone sulfonate anion, and sulfonate group-containing dyes.

Two of R ¹⁰⁰ , R ¹⁰¹ and R ¹⁰² , and Ar ¹ and Ar ² may be bonded via a single bond or a substituent.

  Specific examples include the following compounds, but are not limited thereto.

  Diphenyl iodonium dodecyl benzene sulfonate, diphenyl iodonium trifluoromethane sulfonate, bis (4-trifluoromethylphenyl) iodonium trifluoromethane sulfonate, bis (4-t-butylphenyl) iodonium camphor sulfonate.

  Triphenylsulfonium dodecylbenzenesulfonate, triphenylsulfonium-2,4,6-trimethylbenzenesulfonate, triphenylsulfonium-2,4,6-triisopropylbenzenesulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium perfluorooctanesulfonate , Triphenylsulfonium perfluorononane sulfonate, triphenylsulfonium camphor sulfonate, triphenylsulfonium perfluorobenzene sulfonate, triphenylsulfonium-3,4-bis (trifluoromethyl) benzene sulfonate.

  The above onium salts represented by the general formulas (PAG1) and (PAG2) are known, and can be synthesized, for example, by the methods described in US Pat. Nos. 2,807,648 and 4,247,473, and JP-A-53-101,331.

  (2) A disulfone derivative represented by the following general formula (PAG3) or an iminosulfonate derivative represented by the general formula (PAG4).

Ar ³ and Ar ⁴ each independently represents an aryl group.
R ¹⁰³ represents an alkyl group, a cycloalkyl group or an aryl group. A represents an alkylene group, an alkenylene group or an arylene group.
Specific examples include the following compounds, but are not limited thereto.

  Bis (tolyl) disulfone, bis (4-methoxyphenyl) disulfone, bis (4-trifluoromethylphenyl) disulfone, phenyl-4-isopropylphenyldisulfone.

  (3) A diazodisulfone derivative represented by the following general formula (PAG5).

R ¹⁰⁴ and R ¹⁰⁵ each independently represents an alkyl group, a cycloalkyl group or an aryl group.
Specific examples include the following compounds, but are not limited thereto.

  Bis (phenylsulfonyl) diazomethane, bis (2,4-dimethylphenylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, bis (tolylsulfonyl) diazomethane, bis (t-butylsulfonyl) diazomethane.

  (4) As the acid generator (B), a phenacylsulfonium derivative represented by the following general formula (PAG6) can also be used.

In general formula (PAG6),
R _{1 to} R ₅ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a nitro group, a halogen atom, an alkyloxycarbonyl group or an aryl group, and at least two of R _{1 to} R ₅ The above may combine to form a ring structure.
R ₆ and R ₇ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, a cyano group or an aryl group.
Y ₁ and Y ₂ each independently represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an aromatic group containing a hetero atom, and Y ₁ and Y ₂ may combine to form a ring. Good.
Y ₃ represents a single bond or a divalent linking group.
X ⁻ represents a non-nucleophilic anion.
At least one of R ₁ to R ₅ and at least one of Y ₁ or Y ₂ may be bonded to form a ring, or at least one of R ₁ to R ₅ and at least one of R ₆ or R ₇ may be bonded. To form a ring.
It may be bonded via a linking group at any position of R ₁ to R ₇ or at any position of Y ₁ or Y ₂ and may have two or more structures of the formula (PAG6).

  Specific examples of the compound represented by the above formula (PAG6) are shown below, but the present invention is not limited thereto.

  Among the above-mentioned compounds that decompose upon irradiation with actinic rays to generate an acid, examples of particularly preferable compounds are listed below.

  An acid generator can be used individually by 1 type or in combination of 2 or more types.

  The amount of the acid generator added is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, and still more preferably 1 to 7% by mass, based on the solid content of the composition.

[3] (C) Basic compound The positive resist composition of the present invention uses the basic compound (C) in order to reduce the change in performance over time from exposure to heating, but further suppresses development defects. Therefore, at least two kinds of basic compounds (C) are used in combination.
The molecular weight of the basic compound (C) is preferably 150 to 3000, more preferably 150 to 1500.
Preferred structures of the basic compound (C) include structures represented by the following formulas (A) to (E).

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 having 1 to 20 carbon atoms or a cycloalkyl group, or an aryl group having 6 to 20 carbon atoms. Here, R ²⁰¹ and R ²⁰² may combine with 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.
These may contain an oxygen atom, a sulfur atom, or a nitrogen atom in the alkyl chain.

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.

  Preferred examples include guanidine, aminopyridine, aminoalkylpyridine, aminopyrrolidine, indazole, pyrazole, pyrazine, pyrimidine, purine, imidazoline, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine, mono, di, and trialkylamine. Aniline, piperidine, mono- or diethanolamine and the like. Preferred substituents that these may have include an amino group, an alkylamino group, an aminoaryl group, an arylamino group, an alkyl group (particularly an aminoalkyl group as a substituted alkyl group), an alkoxy group, an acyl group, an acyloxy group, An aryl group, an aryloxy group, a nitro group, a hydroxyl group, a cyano group, etc. are mentioned.

  Preferred compounds include guanidine, 1,1-dimethylguanidine, 1,1,3,3-tetramethylguanidine, 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, -(2-aminoethyl) pyrrolidine, pyrazole, 3-amino-5-methylpyrazole, 5-amino-3-methyl-1-p-tolylpyrazole, pyrazine, 2- (aminomethyl) -5-methylpyrazine, pyrimidine 2,4-diaminopyrimidine, 4,6-dihydroxypyrimidine, 2-pyrazoline, 3-pyrazoline, N-aminomorpholine, N- (2-aminoethyl) morpholine, 1,5-diazabicyclo [4.3. 0] non-5-ene, 1,8-diazabicyclo [5.4.0] undec-7-ene, 2,4,5-triphenylimidazole, tri (n-butyl) amine, tri (n-octyl) Amine, N-phenyldiethanolamine, N-hydroxyethylpiperidine, 2,6-diisopropylaniline, N-cyclohexyl- '- morpholinoethyl but ethyl thiourea, and the like, but is not limited thereto.

  More preferable compounds include guanidine, aminopyrrolidine, pyrazole, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine, piperidine, and compounds having an imidazole structure, diazabicyclo structure, onium hydroxide structure, onium carboxylate structure, or aniline structure. Can be mentioned.

  Examples of the compound having an imidazole structure include imidazole, 2,4,5-triphenylimidazole, benzimidazole, and the like. The compound having a diazabicyclo structure is 1,4-diazabicyclo [2,2,2] octane, 1,5-diazabicyclo [4,3,0] noner-5-ene, 1,8-diazabicyclo [5,4,0]. Undecar 7-ene. Examples of the compound having an onium hydroxide structure include triarylsulfonium hydroxide, phenacylsulfonium hydroxide, sulfonium hydroxide having a 2-oxoalkyl group, specifically triphenylsulfonium hydroxide, tris (t-butylphenyl) sulfonium. Examples thereof include hydroxide, bis (t-butylphenyl) iodonium hydroxide, phenacylthiophenium hydroxide, and 2-oxopropylthiophenium hydroxide. The compound having an onium carboxylate structure is a compound having an onium hydroxide structure in which the anion moiety is converted to a carboxylate, and examples thereof include acetate, adamantane-1-carboxylate, and perfluoroalkylcarboxylate. Examples of aniline compounds include 2,6-diisopropylaniline and N, N-dimethylaniline. Neither is limited to the illustrated specific examples.

  In the present invention, as the basic compound (C), for example, at least two kinds of basic compounds (C) among the above basic compounds (C), for example, two kinds of basic compounds ( C) Three types of basic compounds (C) or four or more types of basic compounds (C) are used. When using at least 2 types of basic compounds (C), it is preferable that the usage-amount of the basic compound (C) used the least amount is 10 mass% or more of the whole basic compounds (C). In the present invention, by using at least two kinds of basic compounds (C) as the basic compound (C), development defects can be suppressed, and line width variation with time can be improved.

In the present invention, mixing two kinds of basic compounds means mixing basic compounds having different physical properties.
Examples of the physical properties include pKa, molecular size (molecular size), melting point, boiling point, vapor pressure, logP, and the like. PKa here represents the pKa of the conjugate acid.

When mixing basic compounds with different pKa, it is imagined to mix those with high pKa and those with low pKa, but not necessarily, high pKa but slightly different, low pKa but slightly It is also possible to mix different things. That is, the pKa difference between the two organic basic compounds is preferably 0.1 or more, and more preferably 0.5 or more.
pKa is a measure representing the basicity of basic nitrogen, and is known to correlate with the charge density on nitrogen. The charge density on nitrogen can be calculated using molecular orbital calculations. For example, for molecular orbital calculation, MOPAC or the like can be used, and the value obtained thereby can be used as a scale indicating basicity, like pKa. Various calculation methods are known. In general, a molecule is sterically optimized by molecular mechanics calculation (for example, using the MM2 parameter), and then the electronic state of the molecule is taken into account. As the molecular orbital calculation, which is the same method, it can be calculated by MOPAC (parameter is AM1), and the charge density can be obtained. When it is determined by this, it is preferable to mix two kinds whose charge values on nitrogen are separated by 0.01 or more, and more preferably two kinds separated by 0.02 or more.

The molecular size is considered as a factor mainly controlling diffusivity. The molecular size represents the size of the molecule and can be quantified by various methods. For example, after optimizing the molecule structure three-dimensionally by molecular mechanics calculation (for example, using the MM2 parameter), the molecular orbital calculation, which takes into account the electronic state of the molecule, is calculated by MOPAC (parameter is PM3). The surface area and volume of the molecule can be determined. In general, it is preferred to use volume rather than surface area. Since the required diffusivity, that is, the size changes depending on the composition, it is not possible to define the ideal size in general, but usually by mixing large and small molecular sizes, The diffusibility can be controlled. When the volume value of the molecule calculated by the previous method is used, the preferable molecular size difference is 10A ³ or more, and more preferably 15A ³ or more.

  The melting point, boiling point, or vapor pressure is a physical property that affects the volatility and compatibility of the molecule, and sometimes the distribution in the resist film. The melting point and boiling point are preferably 10 ° C. or more apart, more preferably 20 ° C. or more.

  LogP is known as an index representing the hydrophilicity / hydrophobicity of a molecule, and is an important factor from the viewpoint of compatibility in a membrane. By mixing organic basic compounds having different log Ps, the distribution in the film can be controlled. The value of logP is preferably 0.2 or more, and more preferably 0.4 or more.

As described above, mixing two kinds of organic basic compounds does not necessarily depend on only one parameter, and therefore usually satisfies two or more conditions. However, it is sufficient to satisfy one condition, and the value is not limited to the preferable range.
Among these parameters, it is particularly preferable to apply pKa or LogP.
Further, it is more preferable to mix three or four kinds of amines. In this case, the minimum value of the difference in log P values is preferably 0.2 or more, and more preferably 0.4 or more. .

  Preferred combinations of the basic compound (C) in the present invention include tri (n-butyl) amine and diisopropylaniline, tri (n-butyl) amine and N, N-dimethylpyridine, tri (n-butyl) amine and 1 , 8-diazabicyclo [5.4.0] undec-7-ene, tri (n-butyl) amine and triphenylimidazole, diisopropylaniline and N, N-dimethylpyridine, diisopropylaniline and 1,8-diazabicyclo [5. 4.0] undec-7-ene, diisopropylaniline and triphenylimidazole, 1,5-diazabicyclo [4.3.0] non-5-ene and antipyrine, diisopropylaniline and dicyclohexylmethylamine, antipyrine and tri (n- Butyl) amine, hydroxyantipyrine and antipi , Tetramethylammonium hydroxide and diisopropylpyrrolaniline, tetramethylammonium hydroxide and tetrabutylammonium hydroxide, tetramethylammonium hydroxide and tri (n-butyl) amine, diisopropylaniline and dicyclohexylmethylamine and tri (n -Butyl) amine, tri (n-butyl) amine and 1,8-diazabicyclo [5.4.0] undec-7-ene and diisopropylaniline, tri (n-butyl) amine and 1,8-diazabicyclo [5. 4.0] undec-7-ene and diisopropylaniline.

(C) The use amount of the basic compound is preferably 0.001 to 10% by mass, more preferably based on the solid content of the positive resist composition by adding at least two types of basic compounds (C). Is 0.01-5 mass%.
Moreover, about the ratio which mixes at least 2 types of basic compounds, Preferably the least basic compound is 10 mass% or more with respect to the total amount of all the basic compounds, More preferably, it is 15 mass% or more.

[4] (D) Fluorine-based and / or silicon-based surfactant The positive resist composition of the present invention further comprises (D) a fluorine-based and / or silicon-based surfactant (fluorine-based surfactant and silicon-based interface). It is preferable to contain any one or two or more of activators and surfactants containing both fluorine atoms and silicon atoms.
When the positive resist composition of the present invention contains the surfactant (D), a resist having good sensitivity and resolution and less adhesion and development defects when using an exposure light source of 250 nm or less, particularly 220 nm or less. A pattern can be given.
As these (D) surfactants, for example, JP-A-62-36663, JP-A-61-226746, JP-A-61-226745, JP-A-62-170950, JP-A-62-170950 are disclosed. No. 63-34540, 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) and (poly (oxyalkylene)) acrylate having C ₈ F ₁₇ groups (or Copolymer of acrylate (or methacrylate), (poly (oxyethylene)) acrylate (or methacrylate), and (poly (oxypropylene)) acrylate (or methacrylate) having a C ₈ F ₁₇ group Coalesce, etc. Can.

  (D) 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] Solvent The composition of the present invention is dissolved in a solvent that dissolves each of the above components and coated on a support. 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 monoethyl 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-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, tetrahi Preferably such Rofuran, the use of these solvents alone or in combination.

  For pattern formation in the manufacture of precision integrated circuit elements, the positive resist composition of the present invention is applied onto a substrate (transparent substrate such as a silicon / silicon dioxide cover, glass substrate, ITO substrate, etc.), dried, It can be preferably carried out by forming a film, irradiating the resist film with actinic rays using a drawing apparatus, heating, developing, rinsing and drying.

Examples of the alkaline developer used for development include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia, 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 of an alkali such as a quaternary ammonium salt such as choline or a cyclic amine such as pyrrole or piperidine can be used. Furthermore, an appropriate amount of an alcohol such as isopropyl alcohol or a nonionic surfactant may be added to the alkaline aqueous solution.
Among these alkaline developers, quaternary ammonium salts are preferable, and tetramethylammonium hydroxide and an aqueous solution of choline are more preferable.
The alkali concentration of the alkali developer is usually from 0.1 to 20% by mass.
The pH of the alkali developer is usually from 10.0 to 15.0.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, the content of this invention is not limited by this.

Synthesis Example 1 (Synthesis of Resin (A-25) of the Present Invention)
In a 1 L autoclave, put 9.4 g (0.10 mol) of norbornene and 19.4 g (0.10 mol) of norbornene-2-carboxylic acid t-butyl ester in 150 ml of 1,1,2-trichloro-trifluoroethylene. And pressurized to 200 psi under a nitrogen atmosphere. Further, 20 g (0.20 mol) of tetrafluoroethylene was injected and heated to 50 ° C. with stirring. To this reaction solution, a solution of 1.2 g of di (4-t-butylcyclohexyl) peroxydicarbonate in 15 ml of 1,1,2-trichloro-trifluoroethylene was poured over 20 minutes, and stirring was further continued for 20 hours. After completion of the reaction, the reaction solution was poured into 2 L of methanol with vigorous stirring to precipitate a white resin. The precipitated resin was filtered off and dried under vacuum to obtain 23.5 g of Resin (1). The molecular weight of the resin (1) by GPC measurement was 9500 in terms of weight average (Mw), and the content of components having a molecular weight of 1000 or less was 15% by mass. After the obtained resin (1) is dissolved in acetone and hexane is added to precipitate the resin, the supernatant is removed, and the remaining solution is dried under reduced pressure to obtain the resin (A-25) of the present invention. Obtained. The molecular weight of the resin (A-25) was 10500 in terms of weight average, and the content of components having a molecular weight of 1000 or less was 10% by mass.

[Examples 1-20 and Comparative Examples 1-2]
The resin synthesized in the above synthesis example and each component described in Table 1 below are dissolved in the solvent described in Table 1 at a solid content concentration of 12% by mass, and then filtered through a 0.1 μm polytetrafluoroethylene filter. Thus, a positive resist composition was prepared. In Table 1, the ratio in the case of multiple use is a mass ratio. The addition amount of the surfactant is 100 ppm with respect to the resist composition containing the solvent.

  In addition, the weight average molecular weight, the degree of dispersion, and the content of components having a molecular weight of 1000 or less of the resins used in each Example and Comparative Example are as shown in Table 2.

  Abbreviations in Table 1 are as follows.

  Photoacid generator: Specific examples z1 to z40 of the component (A)

Abbreviations for basic compounds are as follows. In addition, the ratio of the basic compound in Table 1 is a mass ratio, and the total mass of the basic compound was 0.03 g. 1: tri (n-butyl) amine 2: triphenylimidazole 3: diisopropylaniline 4: antipyrine 5: hydroxyantipyrine 6: 1,5-diazabicyclo [4.3.0] non-5-ene 7: tetramethylammonium hydroxy 8: Tetrabutylammonium hydroxide 9: Dicyclohexylmethylamine

The basic compound has the physical properties shown in Table 3 below.
By comparing Table 3 with the above examples, it can be seen that in each example, two basic compounds having different physical properties are mixed.
In the present invention, the two kinds of basic compounds do not necessarily have different physical properties in all items, but means that at least one physical property should be different.
In addition, since the value of pKa, which is one of the indexes, varies depending on the measurement solvent and the like, it is not described in Table 3, and charge density is described as a substitute index. In the case of amines, the charge density on N basically corresponds to pKa, and in the case of compounds with hydroxy ions (8 and 9), the charge density on oxygen of OH ⁻ corresponds to pKa.

a): The CAChe system was used to optimize the initial structure in terms of molecular dynamics using the MM2 parameter, and then the secondary structure optimization and volume were calculated by MOPAC calculation using the PM3 parameter.
b): Calculated by a general atom calculation method.
c): Using the CAChe system, the initial structure was optimized molecularly using the MM2 parameter, and then the secondary structure was optimized and the volume was calculated by MOPAC calculation using the AM1 parameter.
d): Same as c). However, only when there are two nitrogen atoms in the molecule.
e): Applicable only to molecules whose basicity is OH-. The calculation method is the same as c) and d).
f): A compound containing atoms not included in the parameters of the logP calculation method used, and cannot be calculated.

The symbols for the surfactant are as follows.
W-1: Megafuck F176 (Dainippon Ink Chemical Co., Ltd.) (Fluorine) W-2: Megafuck R08 (Dainippon Ink Chemical Co., Ltd.)
(Fluorine and silicone)
W-3: Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.)
(Silicon)
W-4: Polyoxyethylene nonylphenyl ether W-5: Troisol S-366 (manufactured by Troy Chemical Co., Ltd.)
W-6: Megafuck F-475 (Dainippon Ink Chemical Co., Ltd.)
W-7: a copolymer of an acrylate having a C ₆ F ₁₃ group, (poly (oxypropylene)) acrylate, and (poly (oxyethylene)) methacrylate W-8: an acrylate having a C ₆ F ₁₃ group , (Poly (ethyleneoxy, propyleneoxy and ethyleneoxy block)) acrylate copolymer

The symbols for the solvent are as follows.
A1: Propylene glycol monomethyl ether acetate A2: Ethyl ethoxypropionate A3: γ-butyrolactone A4: Cyclohexanone A5: Propylene glycol monomethyl ether A6: Ethyl lactate

(Evaluation test)
Each resist composition was filtered through a 0.1 μm polytetrafluoroethylene filter, and then applied onto a silicon wafer subjected to hexamethyldisilazane treatment by a spin coater, and then on a vacuum contact hot plate at 110 ° C. for 90 seconds. Heat drying was performed to obtain a resist film having a film thickness of 0.3 μm. The resulting resist film was subjected to image exposure using an F2 stepper (NA 0.60), post-heated at 110 ° C. for 90 seconds, and then developed with a 0.262N aqueous tetramethylammonium hydroxide solution. A 0.5 μm line and space pattern was formed.
About these, the development defect was evaluated as follows.

[Development Defect] For the resist pattern obtained as described above, the number of development defects was measured with a KLA-Tencor KLA-2112 machine, and the obtained primary data value was defined as the number of development defects. The smaller this value, the better.
The evaluation results are shown in Table 1.

  As is clear from the results in Table 1, the composition of the present invention has very few development defects.

Claims (4)

(A) a fluorine-containing resin having a structure in which a fluorine atom is substituted on the main chain of the polymer skeleton, decomposed by the action of an acid, and increases the solubility in an alkali developer;
(B) a compound that generates an acid upon irradiation with actinic rays, and
(C) A positive resist composition containing at least two types of basic compounds. 2. The positive resist according to claim 1, wherein the resin (A) has a weight average molecular weight of 1,000 to 200,000, and the content of a component having a molecular weight of 1,000 or less in the resin (A) is 10% by mass or less. Composition. The resin (A) is a group of repeating units represented by at least one selected from the group of repeating units represented by the following general formulas (I) to (III) and the following general formulas (IV) to (IX): The positive resist composition according to claim 1, wherein the positive resist composition is a resin having at least one selected from the group consisting of:

In general formulas (I) to (IX),
R ₀ and R ₁ may be the same or different and each represents a hydrogen atom, a fluorine atom, an alkyl group, a cycloalkyl group, or an aryl group.
R _{2 to} R ₄ may be the same or different and each represents an alkyl group, a cycloalkyl group, or an aryl group.
R ₀ and R ₁ , R ₀ and R ₂ , R ₃ and R ₄ may combine to form a ring.
R ₅ represents an alkyl group, a cycloalkyl group, an acyl group, or an alkoxycarbonyl group.
R ₆ , R ₇ and R ₈ may be the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group.
R ₉ and R ₁₀ represent a hydrogen atom, a halogen atom, a cyano group or an alkyl group.
R ₁₁ and R ₁₂ may be the same or different and each represents a hydrogen atom, a hydroxyl group, a halogen atom, a cyano group, an alkoxy group, an acyl group, an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group, or an aryl group. .
R ₁₃ and R ₁₄ may be the same or different and each represents a hydrogen atom, a halogen atom, a cyano group or an alkyl group.
R ₁₅ represents —C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), —C (R ₃₆ ) (R ₃₇ ) (OR ₃₉ ) or a group represented by the following general formula (XIV).

R ₃₆ , R ₃₇ , R ₃₈ and R ₃₉ may be the same or different and each represents an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group. Two of R ₃₆ , R ₃₇ and R ₃₈ , or two of R ₃₆ , R ₃₇ and R ₃₉ may be bonded to form a ring.
R ₄₀ represents an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aralkyl group or an aryl group.
Z represents an atomic group constituting a monocyclic or polycyclic alicyclic group together with a carbon atom.
R ₁₆ , R ₁₇ and R ₁₈ may be the same or different and each represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an alkoxy group or —CO—O—R ₁₅ .
A ₁ and A ₂ are a single bond, an alkylene group, an alkenylene group, a cycloalkylene group, an arylene group, a divalent alicyclic group, a divalent linking group formed by combining two or more thereof, or —O—CO—R. _22- , -CO-O-R _23- , -CO-N (R ₂₄ ) -R ₂₅ -are represented.
R ₂₂ , R ₂₃ and R ₂₅ represent a single bond or an alkylene group, an alkenylene group, a cycloalkylene group or an arylene group which may have an ether group, an ester group, an amide group, a urethane group or a ureido group. .
R ₂₄ represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aralkyl group or an aryl group.
n represents 0 or 1, and m represents 1 or 2. A pattern forming method comprising: forming a resist film from the positive resist composition according to claim 1; and exposing and developing the resist film.