JP2005037656A - Positive resist composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive resist composition adaptable to exposure in a far UV region using an actinic ray or radiation, particularly ArF or KrF as a light source in manufacture of a semiconductor device, and excellent in various properties of a resist, such as sensitivity, resolving power, and etching resistance. <P>SOLUTION: The positive resist composition contains (a) a polymer which has silicon in a side chain, is insoluble or slightly soluble in an aqueous alkali solution and is made soluble in an aqueous alkali solution by the action of an acid, and (b) a compound which generates an acid upon irradiation with an actinic ray or radiation and is represented by formula (I) or formula (II). This positive resist composition is applicable as a positive silicon-containing resist composition for microfabrication giving a resist of a rectangular cross-section shape with particularly high resolving power and sensitivity and having large process admissibility. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a positive silicon-containing resist composition for exposure by irradiation with actinic rays or radiation such as ultraviolet rays, far ultraviolet rays, X-rays, electron beams, molecular beams, gamma rays, synchrotron radiation, and the like. A positive silicon-containing resist composition for microfabrication that provides a resist having a particularly high resolving power and sensitivity, a rectangular cross-sectional shape and has a wide process tolerance, for example, used in the production of a semiconductor substrate such as a circuit board. About.

  The positive silicon-containing resist composition of the present invention can be used in the following steps. For example, it is applied to a thickness of 0.01 to 3 μm by a spin coating method or a roller coating method on a semiconductor wafer or a substrate such as glass, ceramics, metal or the like, on which an antireflection layer or an organic film is placed. The Thereafter, it is heated and dried, and a circuit pattern or the like is printed by exposure to actinic rays through an exposure mask and developed to obtain a positive image. Further, the substrate can be processed into a pattern by etching using this positive image as a mask. Typical application fields include semiconductor manufacturing processes such as ICs, circuit boards such as liquid crystals and thermal heads, and other photofabrication processes.

With the high integration of LSI, the resolution limit of conventional single-layer resist becomes clear, and a method to form a high-profile pattern with a large film thickness and fineness by layering the resist instead of a single layer is proposed. Has been. That is, after forming a thick organic polymer film on the first layer and forming a thin resist composition layer on the second layer thereon, the second resist composition is irradiated with actinic rays or radiation and developed. To do. Using the pattern obtained as a mask, the organic polymer of the first layer is anisotropically etched by oxygen plasma etching (O ₂ RIE) to obtain a pattern having a high rectangular shape (phosphorus, solid state) Technology 24, page 73 (1981)).

This two-layer resist method can provide a high resolution, a high aspect ratio, and a wider depth of focus due to the advantage that the second resist layer can be thinned.
In this case, since the second resist layer must have high O ₂ -RIE resistance, a silicon-containing polymer is usually used. In particular, many attempts have been made to use an acid-decomposable group-containing vinyl polymer having a silicon atom in the side chain because of the increased degree of freedom in molecular design, the availability of raw materials, and the ease of synthesis.

For example, a two-layer resist composed of an upper layer containing a substance formed by polymerization of a monomer containing a silicon derivative of methyl methacrylate (Patent Document 1), a resist containing silicon in the ester portion of an acrylate polymer A composition (Patent Document 2), a resist composition having a polymer comprising a silicon-containing monomer, maleic anhydride and t-butyl acrylate (Patent Document 3), and a polymer obtained from an acrylic monomer having two trimethylsilyl groups were used. Examples thereof include a resist composition (Patent Document 4).
JP 7-99435 U.S. Pat. European Patent No. 494383 U.S. Pat.No. 5,998,557

  However, even in such a conventional resist composition, further improvements in sensitivity, resolution, and etching resistance have been desired.

  The object of the present invention is to support exposure in the far ultraviolet region using actinic rays or radiation, particularly ArF or KrF, as a light source in the manufacture of semiconductor devices, and is excellent in positive resist characteristics such as sensitivity, resolving power and etching resistance. It is to provide a mold resist composition.

As a result of intensive investigations by paying attention to the above characteristics, the present inventors have completed the present invention. That is, the object of the present invention can be achieved by the following configuration.
(1) (a) a polymer having a silicon atom in the side chain and insoluble or hardly soluble in an alkaline aqueous solution and soluble in an alkaline aqueous solution by the action of an acid; and (b) an acid upon irradiation with actinic rays or radiation. A positive resist composition comprising a compound represented by the following general formula (I) or (II) that generates

In general formulas (I) and (II),
R _{1 to} R ₃ may be the same or different and each represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, or an alkoxy group.
R ₄ and R ₅ may be the same or different and each represents a hydrogen atom, a cyano group, an alkyl group, an aryl group, or an alkoxy group.
Y ₁ and Y ₂ may be the same or different and each represents an alkyl group, an aryl group, an aralkyl group or an aromatic group containing a hetero atom.
m represents an integer of 1 to 4. When m is 2 or more, a plurality of R ₁ and R ₂ may be the same or different.
Any two or more of R _{1 to} R ₃ , R ₄ , R ₅ , Y ₁ and Y ₂ may be bonded to form a ring structure.
In addition, at any position of R _{1 to} R ₃ , R ₄ , R ₅ , Y ₁ and Y ₂ , they are bonded via a linking group and have two or more structures of the general formula (I) or (II). You may do it.
X ⁻ represents a non-nucleophilic anion.
(2) The polymer of the component (a) is a polymer having a repeating unit represented by the following general formula (1) and at least one repeating unit of the general formulas (2a) and (2b). The positive resist composition as described in (1) above.

In formula (1), R < ¹² > -R < ¹⁴ > represents an alkyl group, a halogen atom, an alkoxy group, a trialkylsilyl group, or a trialkylsilyloxy group each independently. n represents 0 or 1.

In formula (2a), Y ³ represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom. L represents a single bond or a divalent linking group. Q represents a group that can be decomposed with an acid to generate a carboxylic acid.

In formula (2b), X ¹ and X ² each independently represent a group selected from an oxygen atom, a sulfur atom, —NH—, and —NHSO ₂ —. L ¹¹ and L ¹² each independently represents a single bond or a divalent linking group. A ² each independently represents a hydrogen atom, a cyano group, a hydroxyl group, —COOH, —COOR ¹⁵ , —CO—NH—R ¹⁶ , an alkyl group, an alkoxy group, or —COOQ. (R ¹⁵ and R ¹⁶ each independently represents an alkyl group.) Q represents a group capable of decomposing with an acid to generate a carboxylic acid.
(3) The polymer of the component (a) is a repeating unit represented by the general formula (1), at least one repeating unit of the general formulas (2a) and (2b), and the following general formula (3): The positive resist composition as described in (1) above, which is a polymer having a repeating unit represented.

In formula (3), Z represents —O— or —N (R ¹⁷ ) —. Here, R ¹⁷ represents a hydrogen atom, a hydroxyl group, an alkyl group, or —OSO ₂ —R ¹⁸ . R ¹⁸ represents an alkyl group, a cycloalkyl group or a camphor residue.
(4) The positive resist composition as described in (1) above, wherein the polymer of the component (a) has a repeating unit represented by the following general formula (4).

In the formula, R ⁰ represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom. L ²¹ represents a divalent to tetravalent linking group. R ^{12 to} R ¹⁴ each independently represents an alkyl group, a halogen atom, an alkoxy group, a trialkylsilyl group, or a trialkylsilyloxy group. l represents an integer of 1 to 3.
(5) The positive resist composition as described in any one of (1) to (4) above, wherein the positive resist composition further comprises (c) an organic basic compound as an acid scavenger. .

  The positive silicon-containing resist composition of the present invention can cope with exposure in the far ultraviolet region, and is excellent in sensitivity, resolution, and etching resistance in a fine pattern of 0.2 μm or less. Therefore, the composition of the present invention is very suitably used for mass production of semiconductor substrates having ultrafine circuits.

Hereinafter, although embodiments of the present invention will be clarified, the present invention is not limited thereto.
In addition, in the description of 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).

First, the component (a) used in the present invention is a polymer having a silicon atom in a side chain, insoluble or hardly soluble in an aqueous alkali solution, and soluble in an aqueous alkali solution by the action of an acid (hereinafter referred to as “silicon”). "Atom-containing acid-decomposable polymer" or "acid-decomposable polymer") will be described. This polymer is used in the form of the polymer shown below.
That is,
1) Copolymer having as an essential component a repeating unit represented by the general formula (1) and at least one of the repeating unit represented by the general formula (2a) and the repeating unit represented by (2b)
2) The repeating unit represented by the general formula (1), at least one of the repeating unit represented by the general formula (2a) and the repeating unit represented by (2b), and the repeating unit represented by the general formula (3) Copolymer with essential component
3) A homopolymer containing the repeating unit represented by the general formula (4), or a copolymer polymer further containing another monomer component.

In the general formula (1), R ^{12 to} R ¹⁴ each independently represents a group selected from an alkyl group, a halogen atom (Cl, Br, I, etc.), an alkoxy group, a trialkylsilyl group, and a trialkylsilyloxy group. .

  The alkyl group is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, more preferably a linear or branched alkyl group having 1 to 6 carbon atoms, still more preferably a methyl group, an ethyl group, Examples thereof include haloalkyl groups such as n-propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, t-butyl group, chloromethyl group, bromomethyl group and iodomethyl group.

  The alkoxy group is a linear or branched alkoxy group having 1 to 6 carbon atoms, and more preferably a methoxy group, an ethoxy group, an n-propyloxy group, an i-propyloxy group, an n-butoxy group, or an i-butoxy group. Group, s-butoxy group and t-butoxy group, and particularly preferred are methoxy group and ethoxy group.

  The alkyl group of the trialkylsilyl group is a linear or branched alkyl group having 1 to 6 carbon atoms, and more preferably a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, i -Butyl group, s-butyl group, and t-butyl group, and most preferred is a methyl group.

  The alkyl group of the trialkylsilyloxy group is a linear or branched alkyl group having 1 to 6 carbon atoms, and more preferably a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, An i-butyl group, an s-butyl group, and a t-butyl group are preferable, and a methyl group is most preferable among them.

  n represents 0 or 1.

  Specific examples of the repeating unit represented by the general formula (1) include the following, but the present invention is not limited to these specific examples.

In the general formula (2a), Y ³ is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a cyano group, or a halogen atom (Cl, Br, I, etc.), more preferably a hydrogen atom, having 1 to 3 carbon atoms. An alkyl group, particularly preferably a hydrogen atom or a methyl group.

L represents a single bond or a divalent linking group.
Q represents a group that can be decomposed with an acid to generate a carboxylic acid.

  Specific examples of Q include tertiary alkyl groups such as t-butyl group and t-amyl group, isobornyl group, 1-ethoxyethyl group, 1-butoxyethyl group, 1-isobutoxyethyl group, 1-cyclohexyloxyethyl. Groups such as 1-alkoxyethyl group, 1-methoxymethyl group, 1-ethoxymethyl group and other alkoxymethyl groups, tetrahydropyranyl group, tetrahydrofurfuryl group, trialkylsilyl group, 3-oxocyclohexyl group, 2-methyl -Adamantyl group, mevalonic lactone residue, 2- (γ-butyrolactonyloxycarbonyl) -2-propyl group and the like can be mentioned.

  Specific examples of the repeating unit represented by the general formula (2a) include the following, but the present invention is not limited to these specific examples.

In the general formula (2b), X ¹ and X ² each independently represent a group selected from an oxygen atom, a sulfur atom, —NH—, and —NHSO ₂ —.
L ¹¹ and L ¹² each independently represents a single bond or a divalent linking group.

The divalent linking group in L ¹¹ and L ¹² is a single group selected from the group consisting of an alkylene group, an ether group, a thioether group, a carbonyl group, an ester group, an amide group, a sulfonamide group, a urethane group, and a urea group. Or the combination of two or more groups is mentioned.

Examples of the alkylene group in L ¹¹ and L ¹² include groups represented by the following formulas.

− [C (R _a ) (R _b )] _r −
In the formula, R _a and R _b represent a hydrogen atom, an alkyl group, a halogen atom, a hydroxyl group, or an alkoxy group, and both may be the same or different. The alkyl group is preferably a lower alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, or a butyl group, and more preferably selected from a methyl group, an ethyl group, a propyl group, and an isopropyl group. Examples of the alkoxy group include those having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. Examples of the halogen atom include a chlorine atom, a bromine atom, a fluorine atom, and an iodine atom. r represents an integer of 1 to 10. Examples of the substituent that the alkyl group and the alkoxy group may have include a hydroxyl group, a halogen atom, and an alkoxy group.

In General Formula (2b), each A ² independently represents a hydrogen atom, a cyano group, a hydroxyl group, —COOH, —COOR ¹⁵ , —CO—NH—R ¹⁶ , an alkyl group, an alkoxy group, or —COOQ. (R ¹⁵ and R ¹⁶ each independently represents an alkyl group.)
The alkyl group in A ² , R ¹⁵ and R ¹⁶ may have a substituent, and is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, more preferably a linear chain having 1 to 6 carbon atoms. Or it is a branched alkyl group, More preferably, they are a methyl group, an ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, and t-butyl group. Similarly, the alkoxy group is a linear or branched alkoxy group having 1 to 6 carbon atoms, and more preferably a methoxy group, an ethoxy group, an n-propyloxy group, an i-propyloxy group, an n-butoxy group, an i- A butoxy group, an s-butoxy group, and a t-butoxy group, and particularly preferred are a methoxy group and an ethoxy group.

  Q represents a group that can be decomposed with an acid to generate a carboxylic acid.

  Similarly, Q is the same group as Q of the repeating unit (2a).

  Specific examples of the repeating unit represented by the general formula (2b) include the following, but the present invention is not limited to these specific examples.

In the general formula (3), Z represents —O— or —N (R ¹⁷ ) —.
Here, R ¹⁷ represents a hydrogen atom, a hydroxyl group, an alkyl group, or —OSO ₂ —R ¹⁸ .
R ¹⁸ represents an alkyl group, a cycloalkyl group or a camphor residue.

The alkyl group in R ¹⁷ and R ¹⁸ is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, more preferably a linear or branched alkyl group having 1 to 6 carbon atoms. More preferably, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, trifluoromethyl group, nanofluorobutyl group, pentadecafluorooctyl group, A haloalkyl group such as a trichloromethyl group can be mentioned.
Examples of the cycloalkyl group for R ¹⁸ include a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group.

The alkyl group as R ¹⁷ and R ¹⁸ , the cycloalkyl group as R ¹⁸ , or the camphor residue may have a substituent. Examples of such a substituent include a hydroxyl group, a carboxyl group, a cyano group, a halogen atom (for example, a chlorine atom, a bromine atom, a fluorine atom, and an iodine atom), an alkoxy group (preferably having 1 to 4 carbon atoms, for example, methoxy Group, ethoxy group, propoxy group, butoxy group, etc.), acyl group (preferably having 2 to 5 carbon atoms, such as formyl group, acetyl group, etc.), acyloxy group (preferably having 2 to 5 carbon atoms, such as acetoxy group), An aryl group (preferably having 6 to 14 carbon atoms, for example, a phenyl group) and the like can be mentioned.

  Specific examples of the repeating unit represented by the general formula (3) include the following, but the present invention is not limited to these specific examples.

  In the form of the above 1), used as the component (a) of the present invention, the content of the repeating unit represented by the general formula (1) and at least one repeating unit of the general formulas (2a) and (2b) Can be set as appropriate in consideration of resist performance such as oxygen plasma etching resistance of the resist, substrate adhesion, sensitivity, profile, and resolving power.

  Content of the repeating unit represented by General formula (1) is 10-90 mol%, Preferably it is 15-70 mol%, More preferably, it is 20-50 mol%. The content of at least one repeating unit among the repeating units (2a) and (2b) is 10 to 90 mol%, more preferably 25 to 50 mol%.

  In addition, in the form of 2) used as the component (a) of the present invention, the repeating unit represented by the general formula (1) and at least one repeating unit of the general formulas (2a) and (2b) Furthermore, also in the acid-decomposable polymer containing the repeating unit represented by the general formula (3), the content of the repeating unit can be appropriately set from the same viewpoint as described above.

  Content of the repeating unit represented by General formula (1) is 10-90 mol%, Preferably it is 15-70 mol%, More preferably, it is 20-50 mol%. Further, the content of at least one repeating unit among the repeating units (2a) and (2b) is 5 to 50 mol%, preferably 10 to 40%.

  Content of a repeating unit (3) is 10-90 mol%, Preferably it is 15-70 mol%, More preferably, it is 20-60%.

  Next, general formula (4) will be described.

In the general formula (4), R ⁰ has the same meaning as Y ³ in the formula (2a), R ¹² ~R ¹⁴ has the same meaning as R ¹² to R ¹⁴ in the formula (1).

L ²¹ represents a divalent to tetravalent linking group, specifically, an alkylene group, a cycloalkylene group, a phenylene group, an arylene group, an aralkylene group, or a group obtained by combining these groups. An —O— structure, —COO— structure, or —O (CO) — structure may be included in the middle.

  The linking group may have a substituent. Examples of the substituent include a halogen atom such as Cl and Br, a —CN group, an —OH group, an amino group, an alkyl group having 1 to 4 carbon atoms, and a carbon number. A C3-C8 cycloalkyl group, a C1-C4 alkoxy group, a C6-C12 aryl group, a C7-C14 aralkyl group, etc. are mentioned.

When L ²¹ is a divalent linking group, it is preferably an alkylene group having 1 to 8 carbon atoms, a phenylene group, or a group obtained by combining these groups, particularly preferably an alkylene group having 1 to 6 carbon atoms (methylene group). An ethylene group, a propylene group, a butylene group, a —C (CH ₃ ) ₂ —CH ₂ — group, a —C (CH ₃ ) ₂ —CH ₂ CH ₂ — group, and the like.

When L ²¹ is a trivalent linking group, it is preferably an alkylene group having 1 to 10 carbon atoms, a phenylene group, or a group obtained by combining these groups, and particularly preferably a trivalent group shown below.

When L ²¹ is a tetravalent linking group, it is preferably an alkylene group having 1 to 10 carbon atoms, a phenylene group, or a group obtained by combining these groups, and particularly preferably a tetravalent group shown below.

  l represents an integer of 1 to 3.

  In the repeating unit represented by the general formula (4), when the silicon atom is in the β-position of the ether oxygen of the ester group in the repeating unit, only this repeating unit functions as an acid-decomposable group. In this case, the polymer of component (a) may or may not contain a polymer component containing an acid-decomposable group.

  In addition, when the silicon atom is other than the β-position of the ether oxygen of the ester group in the repeating unit, the polymer of the component (a) contains a polymer component containing an acid-decomposable group in addition to this. Examples of these acid-decomposable group-containing polymer components are the same as those mentioned in the description of the general formulas (2a) and (2b).

  Specific examples of the repeating unit represented by the general formula (4) include the following, but the present invention is not limited to these specific examples.

  When the repeating unit represented by the general formula (4) functions as an acid-decomposable group, the content of the repeating unit represented by the general formula (4) in the polymer of the component (a) is determined by oxygen plasma etching of the resist. It can be appropriately set in consideration of resist performance such as resistance, substrate adhesion, sensitivity, profile, and resolving power.

  The content of the repeating unit represented by the general formula (4) is preferably 10 to 100%, more preferably 20 to 90%, and particularly preferably 25 to 80%.

  Further, when the repeating unit represented by the general formula (4) does not function as an acid-decomposable group, the content in the polymer of the general formula (4) is similarly set as appropriate, but preferably 10 to 90 mol%. Preferably, it is 15-70 mol%, More preferably, it is 20-50 mol%.

  The content of at least one repeating unit among the repeating units (2a) and (2b) is 10 to 90 mol%, more preferably 25 to 50 mol%.

  In addition to the repeating units represented by the general formulas (1), (2a), (2b), (3), and (4), the polymer of the component (a) used in the present invention is a film forming property and adhesion. Further, it may be a copolymer containing other repeating units for the purpose of improving developability and the like.

  As the monomer corresponding to such other repeating unit, for example, an addition polymerizable non-polymerization selected from acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters and the like. A compound having one saturated bond is exemplified.

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, amyl acrylate, acrylic Cyclohexyl acid, ethylhexyl acrylate, octyl acrylate, tert-octyl acrylate, chloroethyl acrylate, trimethylolpropane monoacrylate, pentaerythritol monoacrylate, benzyl acrylate, methoxybenzyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate etc);
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, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate) Chlorobenzyl methacrylate, octyl methacrylate, trimethylolpropane monomethacrylate, pentaerythritol monomethacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate, etc.);
Acrylamides such as acrylamide, N-alkylacrylamide (alkyl groups having 1 to 10 carbon atoms, such as methyl group, ethyl group, propyl group, butyl group, t-butyl group, heptyl group, octyl group, cyclohexyl group) , Hydroxyethyl group, etc.), N, N-dialkylacrylamide (alkyl groups having 1 to 10 carbon atoms such as methyl, ethyl, butyl, isobutyl, ethylhexyl, cyclohexyl, etc.) N-hydroxyethyl-N-methylacrylamide, N-2-acetamidoethyl-N-acetylacrylamide and the like;

Methacrylamides such as methacrylamide, N-alkyl methacrylamide (alkyl groups having 1 to 10 carbon atoms such as methyl, ethyl, t-butyl, ethylhexyl, hydroxyethyl, cyclohexyl, etc.) N, N-dialkylmethacrylamide (there are alkyl groups such as ethyl, propyl and butyl), N-hydroxyethyl-N-methylmethacrylamide and the like;
Allyl compounds such as allyl esters (eg allyl acetate, allyl caproate, allyl caprylate, allyl laurate, allyl palmitate, allyl stearate, allyl benzoate, allyl acetoacetate, allyl lactate, etc.), allyloxyethanol, etc .;
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 knee, etc.);
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, vinyl acetoacetate Vinyl lactate, vinyl-β-phenylbutyrate, vinylcyclohexylcarboxylate and the like;
Dialkyl itaconates (eg, dimethyl itaconate, diethyl itaconate, dibutyl itaconate, etc.); dialkyl esters of fumaric acid (eg, dibutyl fumarate) or monoalkyl esters;
Examples include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic anhydride, maleimide, acrylonitrile, methacrylonitrile, and maleilonitrile.

  In addition, any addition-polymerizable unsaturated compound that can be copolymerized with the above various repeating units may be used.

  The weight average molecular weight of the polymer of the component (a) used in the present invention is not particularly limited, but with the photoacid generator and other additives used as the component (b) and / or (c) described later. From compatibility, organic solvent property, film forming property, etc., 1000-1 million are preferable, Furthermore, 000-100,000 are preferable.

  In addition, the polymer of component (a) used in the present invention may be used alone or in combination of two or more. The amount of the component (a) polymer used is 40 to 99% by weight, preferably 60 to 98% by weight, based on the total weight of the resist composition (excluding the solvent).

  Although the specific example of the polymer of the (a) component used for this invention below is shown, it is not limited to these. The numbers in parentheses are mole fractions.

(B) A compound represented by the general formula (I) or (II) that generates an acid upon irradiation with an actinic ray or radiation (also referred to as a photoacid generator).
The compound that generates an acid upon irradiation with an actinic ray or radiation is a compound that generates an acid upon irradiation with an actinic ray such as infrared rays, visible light, ultraviolet light, or far ultraviolet light, or radiation such as X-rays or electron beams.

In general formulas (I) and (II), R _{1 to} R ₃ may be the same or different and each represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, or an alkoxy group. R ₄ and R ₅ may be the same or different and each represents a hydrogen atom, a cyano group, an alkyl group, an aryl group, or an alkoxy group.
Y ₁ and Y ₂ may be the same or different and each represents an alkyl group, an aryl group, an aralkyl group or an aromatic group containing a hetero atom. n represents an integer of 1 to 4. When n is 2 or more, a plurality of R ₁ and R ₂ may be the same or different. Any two or more of R _{1 to} R ₃ , R ₄ , R ₅ , Y ₁ and Y ₂ may be bonded to form a ring structure. In addition, at any position of R _{1 to} R ₃ , R ₄ , R ₅ , Y ₁ and Y ₂ , they are bonded via a linking group and have two or more structures of the general formula (I) or (II). You may do it. X ⁻ represents a non-nucleophilic anion.

The alkyl group of R _{1 to} R ₅ , Y ₁ and Y ₂ is preferably an alkyl group having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, Examples thereof include linear, branched and cyclic alkyl groups such as t-butyl group, pentyl group, cyclopentyl group, hexyl group and cyclohexyl group. The alkyl group may have an oxygen atom, a sulfur atom, a carbonyl group or the like in the alkyl chain.

The aryl group of R _{1 to} R ₅ , Y ₁ and Y ₂ is preferably an aryl group having 6 to 14 carbon atoms, and examples thereof include a phenyl group, a tolyl group, and a naphthyl group.

The alkenyl group of R _{1 to} R ₃ is preferably an alkenyl group having 2 to 6 carbon atoms, such as a vinyl group, a propenyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, a cyclopentenyl group, a cyclohexenyl group, A 3-oxocyclopentenyl group, a 3-oxocyclohexenyl group, etc. can be mentioned.

The alkoxy group of R _{1 to} R ₅ is preferably an alkoxy group having 1 to 8 carbon atoms. For example, methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, butoxy group, pentoxy group, allyloxy group, octoxy group Etc.

The aralkyl group of Y ₁ and Y ₂ is preferably an aralkyl group having 7 to 12 carbon atoms, and examples thereof include a benzyl group, a phenethyl group, and a cumyl group.

The aromatic group containing a hetero atom of Y ₁ and Y ₂ is a group having a hetero atom, for example, a nitrogen atom, an oxygen atom, a sulfur atom, etc. in an aromatic group such as an aryl group having 4 to 14 carbon atoms. To express.

Examples of the aromatic group containing a hetero atom of Y ₁ and Y ₂ include heterocyclic aromatic hydrocarbon groups such as furan, thiophene, pyrrole, pyridine, and indole.

As the ring structure formed by combining two or more of R _{1 to} R ₃ , R ₄ , R ₅ , Y ₁ and Y ₂ , for example, R ₁ or R ₂ and R ₃ are bonded. A ring structure formed, a ring structure formed by combining R ₁ or R ₂ and R ₄ or R ₅ , a ring structure formed by combining R ₃ and R ₄ or R ₅ , R ₁ ; A ring structure formed by combining R ₂ and R ₄ or R ₅ ; a ring structure formed by combining R ₁ , R ₂ , R ₃ and R ₄ or R ₅ ; Y ₁ ; Y ₂ and can be exemplified ring structures such as to form together with S ⁺ in the general formula bonded (I) or (II).

When R ₁ or R ₂ and R ₃ combine to form a ring structure, the group formed by combining R ₁ or R ₂ and R ₃ preferably has 1 to 10 carbon atoms. And an alkylene group such as a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, and a hexylene group.

When R ₁ or R ₂ and R ₄ or R ₅ combine to form a ring structure, the group formed by combining R ₁ or R ₂ and R ₄ or R ₅ includes, for example, alkylene Group, carbonyl group and the like. As an alkylene group, Preferably, a C1-C10 alkylene group, for example, a methylene group, ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group etc. can be mentioned.

When R ₃ and R ₄ or R ₅ combine to form a ring structure, the group formed by combining R ₃ and R ₄ or R ₅ preferably has 1 to 10 carbon atoms. And an alkylene group such as a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, and a hexylene group.

A ring structure formed by combining R ₁ , R ₂ and R ₄ or R ₅ and a ring structure formed by combining R ₁ , R ₂ , R ₃ and R ₄ or R ₅ Examples thereof include a bicyclic fused ring structure having 5 to 15 carbon atoms, and may have a hetero atom in the ring.

Y ₁ and Y ₂ may combine to form a ring structure together with S ⁺ in the general formula (I) or (II).

In this case, examples of the group formed by combining Y ₁ and Y ₂ include an alkylene group having 4 to 10 carbon atoms, preferably a butylene group, a pentylene group, and a hexylene group, and particularly preferably a butylene group and a pentylene group. Can be mentioned.

Further, the ring formed by combining Y ₁ and Y ₂ together with S ⁺ in the general formula (I) or (II) may contain a hetero atom.

  Each of the alkyl group, alkenyl group, aryl group, aralkyl group, aromatic group, and cyclic structure may have a substituent. Examples of the substituent include a nitro group, a halogen atom, a carboxyl group, a hydroxyl group, an oxo group, an amino group, a cyano group, and an alkoxy group (preferably having 1 to 5 carbon atoms). In addition, about the aromatic site | part of these groups, an alkyl group (preferably C1-C5) can be mentioned further.

  Moreover, as a substituent of an alkyl group, a halogen atom, a hydroxyl group, and an alkoxy group are preferable.

Examples of the non-nucleophilic anion of X ⁻ include a sulfonate anion, a carboxylate anion, a bis (alkylsulfonyl) imide anion, and a tris (alkylsulfonyl) methyl anion.

  The non-nucleophilic anion is an anion having an extremely low ability to cause a nucleophilic reaction, and is an anion capable of suppressing degradation with time due to intramolecular nucleophilic reaction. This improves the temporal stability of the resist.

  Examples of the sulfonate anion include an alkyl sulfonate anion, an aryl sulfonate anion, and a camphor sulfonate anion.

  Examples of the carboxylate anion include an alkylcarboxylate anion, an arylcarboxylate anion, and an aralkylcarboxylate anion.

  The alkyl group in the alkylsulfonate anion is preferably an alkyl group having 1 to 30 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, or a pentyl group. , Neopentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, cyclo Examples thereof include a propyl group, a cyclopentyl group, a cyclohexyl group, an adamantyl group, a norbornyl group, and a boronyl group.

  Preferred examples of the aryl group in the aryl sulfonate anion include aryl groups having 6 to 14 carbon atoms, such as a phenyl group, a tolyl group, and a naphthyl group.

  The alkyl group and aryl group in the alkyl sulfonate anion and aryl sulfonate anion may have a substituent.

  Examples of the substituent include a halogen atom, an alkyl group, an alkoxy group, and an alkylthio group.

  Examples of the halogen atom include a chlorine atom, a bromine atom, a fluorine atom, and an iodine atom.

  As the alkyl group, for example, preferably an alkyl group having 1 to 15 carbon atoms, for example, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, pentyl group, neopentyl group Hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group, etc. it can.

  Examples of the alkoxy group include preferably an alkoxy group having 1 to 5 carbon atoms, such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group.

  As the alkylthio group, for example, preferably an alkylthio group having 1 to 15 carbon atoms, for example, methylthio group, ethylthio group, propylthio group, isopropylthio group, n-butylthio group, isobutylthio group, sec-butylthio group, pentylthio group, Neopentylthio, hexylthio, heptylthio, octylthio, nonylthio, decylthio, undecylthio, dodecylthio, tridecylthio, tetradecylthio, pentadecylthio, hexadecylthio, heptadecylthio, octadecylthio, nonadecylthio Group, eicosylthio group and the like. The alkyl group, alkoxy group, and alkylthio group may be further substituted with a halogen atom (preferably a fluorine atom).

  Examples of the alkyl group in the alkylcarboxylate anion include the same alkyl groups as in the alkylsulfonate anion.

  Examples of the aryl group in the arylcarboxylate anion include the same aryl groups as in the arylsulfonate anion.

  The aralkyl group in the aralkyl carboxylate anion is preferably an aralkyl group having 6 to 12 carbon atoms, such as benzyl group, phenethyl group, naphthylmethyl group, naphthylethyl group, naphthylmethyl group and the like.

  The alkyl group, aryl group and aralkyl group in the alkylcarboxylate anion, arylcarboxylate anion and aralkylcarboxylate anion may have a substituent. Examples of the substituent are the same as those in the arylsulfonate anion. A halogen atom, an alkyl group, an alkoxy group, an alkylthio group, etc. can be mentioned.

  The alkyl group in the bis (alkylsulfonyl) imide anion and tris (alkylsulfonyl) methyl anion is preferably an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, An isobutyl group, a sec-butyl group, a pentyl group, a neopentyl group, and the like can be given. These alkyl groups may have a substituent, and examples of the substituent include a halogen atom, an alkoxy group, and an alkylthio group.

  Examples of other non-nucleophilic anions include fluorinated phosphorus, fluorinated boron, and fluorinated antimony.

As the non-nucleophilic anion of X ⁻ , an alkanesulfonic acid anion in which the α-position of the sulfonic acid is substituted with a fluorine atom, an arylsulfonic acid anion substituted with a fluorine atom or a group having a fluorine atom, and an alkyl group having a fluorine atom A bis (alkylsulfonyl) imide anion substituted with a tris (alkylsulfonyl) methide anion substituted with a fluorine atom in the alkyl group, particularly preferably a perfluoroalkanesulfonic acid anion having 1 to 8 carbon atoms, most preferably Nonafluorobutane sulfonate anion and perfluorooctane sulfonate anion.

In the general formula (I) or (II), at any position of R _{1 to} R ₃ , R ₄ , R ₅ , Y ₁ and Y ₂ , a bond is formed through a linking group, and the general formula (I) or ( It may have two or more structures of II).

  The acid generator (b) of the present invention is characterized by having a double bond conjugated with a carbonyl group, whereby the excited state is stabilized and the acid generating ability is improved.

When R ₁ or R ₂ and R ₄ or R ₅ are bonded to form a ring structure, or R ₃ and R ₄ or R ₅ are bonded to form a ring structure, the steric structure is carbonyl. It is more preferable because the π ^* orbital and the C−S ⁺ σ orbital are fixed so as to be parallel and the acid generation ability is improved.

  In the photoacid generator (b), n = 1 or 2 is preferable, and n = 1 is particularly preferable.

It is preferable that any two of R _{1 to} R ₅ are bonded via an alkylene group to form a 5- to 7-membered ring or a polycyclic ring structure containing a 5 to 7-membered ring.

R ₄ and R ₅ are preferably a hydrogen atom or an alkyl group.

Y ₁ and Y ₂ are preferably bonded via an alkylene group to form a 5- to 7-membered ring.

  Although the preferable specific example of the compound represented by the said general formula (I) or (II) of this invention is shown below, this invention is not limited to this.

  The compound of the said general formula (I) or (II) can be used individually by 1 type or in combination of 2 or more types.

  The compound represented by the general formula (I) or (II) is obtained by subjecting the corresponding unsaturated ketone compound to silyl enol etherification with trimethylsilyl chloride or the like under basic conditions, and then reacting with a sulfoxide to obtain a sulfonium salt, which is subjected to salt exchange. Can be synthesized.

  In addition, the compound represented by the general formula (I) or (II) is obtained by halogenating the α-position or allyl position of the ketone of the corresponding unsaturated ketone compound with bromine or copper bromide, and the like. It is also possible to synthesize a halogenated unsaturated ketone, then react it with a sulfide compound in the presence of a non-catalyst or a silver catalyst to form a sulfonium salt, and perform salt exchange.

The content of the component (b) compound in the positive resist composition of the present invention is preferably 0.1 to 20% by weight, more preferably 0.5 to 10% by weight, based on the solid content of the composition. More preferably, it is 1 to 7% by weight.

(B) Acid generating compound that can be used in combination with component other than component In the present invention, in addition to component (b), a compound that decomposes upon irradiation with actinic rays or radiation to generate an acid may be used in combination.

  The amount of the acid generator that can be used in combination with the component (b) of the present invention is usually 100/0 to 20/80, preferably 100/0, in a molar ratio (component (b) / other acid generator). 40/60, more preferably 100/0 to 50/50.

  In particular, when an acid generator having an aromatic ring structure is used in combination, the amount used is preferably 60% or less, more preferably 50% or less of the total acid generator in weight ratio.

  Examples of such acid generators that can be used in combination include photocation polymerization photoinitiators, photoradical polymerization photoinitiators, dye photodecolorants, photochromic agents, and actives used in microresists. Known compounds that generate an acid upon irradiation with light or radiation and mixtures thereof can be appropriately selected and used.

  Examples thereof include diazonium salts, phosphonium salts, sulfonium salts, iodonium salts, imide sulfonates, oxime sulfonates, diazodisulfones, disulfones, and o-nitrobenzyl sulfonates.

  Particularly preferred are sulfonium salts, and triarylsulfonium salts, phenacylsulfonium salts, and sulfonium salts having a 2-oxoalkyl group are most preferred.

  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.

  Among the compounds that can be used in combination with an active ray or radiation to generate an acid upon decomposition, compounds represented by the following general formulas (ZI), (ZII), and (ZIII) are exemplified. Can do.

In the above general formula (ZI), R ₂₀₁ , R ₂₀₂ and R ₂₀₃ each independently represents an organic group.

X ⁻ represents a non-nucleophilic anion, and examples thereof include the same as the non-nucleophilic anion of X ⁻ in formulas (I) and (II).

The carbon number of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ is generally 1-30, preferably 1-20.

Two of R _{201 to} R ₂₀₃ may be bonded to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group.

The two of the group formed by bonding of the R ₂₀₁ to R _203, there can be mentioned an alkylene group (e.g., butylene, pentylene).

Specific examples of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ include corresponding groups in the compounds (Z1-1), (Z1-2) and (Z1-3) described later.

In addition, the compound which has two or more structures represented by general formula (ZI) may be sufficient. For example, the general formula at least one of R ₂₀₁ to R ₂₀₃ of a compound represented by (ZI) is, at least one bond with structure of R ₂₀₁ to R ₂₀₃ of another compound represented by formula (ZI) It may be a compound.

  More preferable examples of the (ZI) component include compounds (Z1-1), (Z1-2), and (Z1-3) described below.

The compound (Z1-1) is a triarylsulfonium compound in which each of R _{201 to} R _{203 in} the general formula (ZI) is an aryl group, that is, a compound having triarylsulfonium as a cation.

  The aryl group of the triarylsulfonium cation is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. The three aryl groups of the triarylsulfonium cation may be the same or different.

  Each aryl group may have an alkyl group (for example, 1 to 15 carbon atoms), an alkoxy group (for example, 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, or a phenylthio group as a substituent. Preferred substituents are linear, branched or cyclic alkyl groups having 1 to 12 carbon atoms, linear, branched or cyclic alkoxy groups having 1 to 12 carbon atoms, most preferably alkyl groups having 1 to 4 carbon atoms, It is a C1-C4 alkoxy group. The substituent may be substituted with any one of the three aryl groups, or may be substituted with all three. The substituent is preferably substituted at the p-position of the aryl group.

  Next, the compound (Z1-2) will be described.

Compound (Z1-2) is a compound in the case where R _{201 to} R ₂₀₃ in formula (ZI) each independently represents an organic group not containing an aromatic ring. Here, the aromatic ring includes an aromatic ring containing a hetero atom.

The organic group having no aromatic ring as R ₂₀₁ to R ₂₀₃ generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.

R _{201 to} R ₂₀₃ are each independently preferably an alkyl group, an allyl group, or a vinyl group, more preferably a linear, branched, cyclic 2-oxoalkyl group, an alkoxycarbonylmethyl group, most preferably a linear group, A branched 2-oxoalkyl group.

The alkyl group as R ₂₀₁ to R ₂₀₃ may be linear, branched, or cyclic, preferably a linear or branched alkyl group (e.g., methyl group having 1 to 10 carbon atoms, an ethyl group, a propyl Group, butyl group, pentyl group) and cyclic alkyl groups having 3 to 10 carbon atoms (cyclopentyl group, cyclohexyl group, norbornyl group).

  More preferably, it is a 2-oxoalkyl group or an alkoxycarbonylmethyl group, and the 2-oxoalkyl group may be linear, branched or cyclic, and preferably at the 2-position of the above alkyl group> Mention may be made of groups having C═O.

  Further, the alkoxy group in the alkoxycarbonylmethyl group is preferably an alkyl group having 1 to 5 carbon atoms (methyl group, ethyl group, propyl group, butyl group, pentyl group).

R _{201 to} R ₂₀₃ may be further substituted with a halogen atom, an alkoxy group (for example, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.

Two members out of R _{201 to} R ₂₀₃ may combine to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group. The two of the group formed by bonding of the R ₂₀₁ to R _203, there can be mentioned an alkylene group (e.g., butylene, pentylene).

  The compound (Z1-3) is a compound represented by the following general formula (Z1-3), and is a compound having a phenacylsulfonium salt structure.

R _{1c to} R _5c each independently represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom (Cl, Br, I, etc.).

R _6c and R _7c each independently represents a hydrogen atom, an alkyl group, or an aryl group.

  Rx and Ry each independently represents an alkyl group, an allyl group, or a vinyl group.

Any two or more of R _1c to R _7c, and Rx and Ry may combine with each other to form a ring structure, the ring structure may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond You may go out.

Zc ⁻ represents a non-nucleophilic anion, and examples thereof include the same non-nucleophilic anion as X ⁻ in formulas (I) and (II).

The alkyl group as R _{1c to} R _{5c may} be linear, branched or cyclic, for example, an alkyl group having 1 to 10 carbon atoms, preferably a linear or branched alkyl group having 1 to 5 carbon atoms. (For example, a methyl group, an ethyl group, a linear or branched propyl group, a linear or branched butyl group, a linear or branched pentyl group), a C3-C8 cyclic alkyl group (for example, a cyclopentyl group, a cyclohexyl group). Can be mentioned.

The alkoxy group as R _{1c to} R _{5c may} be linear, branched or cyclic, for example, an alkoxy group having 1 to 10 carbon atoms, preferably a linear or branched alkoxy group having 1 to 5 carbon atoms. (For example, methoxy group, ethoxy group, linear or branched propoxy group, linear or branched butoxy group, linear or branched pentoxy group), C3-C8 cyclic alkoxy group (for example, cyclopentyloxy group, cyclohexyloxy group) ).

Preferably either a straight chain of R _1c to R _5c, branched, cyclic alkyl group, or a linear, branched or cyclic alkoxy group, more preferably the sum of the carbon atoms of R _5c from R _1c 2 to 15 It is. Thereby, solvent solubility improves more and generation | occurrence | production of a particle is suppressed at the time of a preservation | save.

_Examples of the alkyl group as R _6c and R _7c include the same alkyl groups as R _{1c to} R _5c .
As an aryl group, a C6-C14 aryl group (for example, phenyl group) can be mentioned, for example.

The alkyl group as Rx and Ry may be the same as those of the alkyl group as R _1c to R _5c.

Preferably, it is a 2-oxoalkyl group or an alkoxycarbonylmethyl group, and examples of the 2-oxoalkyl group include a group having> C═O at the 2-position of the alkyl group as R _{1c to} R _5c .

Examples of the alkoxy group in the alkoxycarbonylmethyl group include the same alkoxy groups as R _{1c to} R _5c .

  Examples of the group formed by combining Rx and Ry include a butylene group and a pentylene group.

In formula (ZII), (ZIII), R 204 ~R 207 each independently represents an aryl group or an alkyl group.

Phenyl group and a naphthyl group are preferred as the aryl group of R ₂₀₄ to R _207, more preferably a phenyl group.

The alkyl group as R _{204 to} R ₂₀₇ may be linear, branched or cyclic, and is preferably a linear or branched alkyl group having 1 to 10 carbon atoms (for example, methyl group, ethyl group, propyl group). Group, butyl group, pentyl group) and cyclic alkyl groups having 3 to 10 carbon atoms (cyclopentyl group, cyclohexyl group, norbornyl group).

R _{204 to} R ₂₀₇ may have a substituent. Examples of the substituent include an alkyl group (for example, 1 to 15 carbon atoms), an aryl group (for example, 6 to 15 carbon atoms), and an alkoxy group (for example, carbon Mathematical formulas 1 to 15), halogen atoms, hydroxyl groups, phenylthio groups and the like.

X ⁻ represents a non-nucleophilic anion, and examples thereof include the same as the non-nucleophilic anion of X ⁻ in formulas (I) and (II).

  Examples of particularly preferable compounds among the compounds that are decomposed by irradiation with actinic rays or radiation that may be used in combination are listed below.

  The positive resist composition of the present invention preferably further contains an organic basic compound (c) as an acid scavenger. As the organic basic compound used in the present invention, a compound having a stronger basicity than phenol is preferable.

  In particular, nitrogen-containing basic compounds having the following structures (A) to (E) are preferably used.

  By using this organic basic compound, there is an effect that the change in performance over time from exposure to post-heating can be reduced.

Here, R ²⁵⁰ , R ²⁵¹ and R ²⁵² are the same or different and are a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 20 carbon atoms, wherein R ²⁵¹ and R ²⁵² are mutually They may combine to form a ring.
The alkyl group may be unsubstituted or have a substituent. Examples of the alkyl group having a substituent include an aminoalkyl group having 1 to 6 carbon atoms and a hydroxyalkyl group having 1 to 6 carbon atoms. Is preferred.

In the formula, R ²⁵³ , R ²⁵⁴ , R ²⁵⁵ and R ²⁵⁶ are the same or different and represent an alkyl group having 1 to 6 carbon atoms.
Further preferred compounds are nitrogen-containing cyclic compounds or basic nitrogen-containing compounds having two or more nitrogen atoms having different chemical environments in one molecule.

  The nitrogen-containing cyclic compound is more preferably a polycyclic structure. Preferable specific examples of the nitrogen-containing polycyclic compound include compounds represented by the following general formula (III).

  In formula (III), Y and W may each independently contain a hetero atom, and represent a linear, branched or cyclic alkylene group.

Here, examples of the hetero atom include a nitrogen atom, a sulfur atom, and an oxygen atom.
The alkylene group preferably has 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms. The alkylene group may have a substituent, and examples of the substituent include a halogen atom and a halogen-substituted alkyl group in addition to an alkyl group having 1 to 6 carbon atoms, an aryl group, and an alkenyl group.

  Furthermore, specific examples of the compound represented by the general formula (III) include the compounds shown below.

  Among these, 1,8-diazabicyclo [5.4.0] undec-7-ene and 1,5-diazabicyclo [4.3.0] non-5-ene are particularly preferable.

  The basic nitrogen-containing compound having two or more nitrogen atoms having different chemical environments in one molecule is particularly preferably a compound having both an amino group and a ring structure containing a nitrogen atom or a compound having an alkylamino group. is there. Preferred examples include guanidine, aminopyridine, aminoalkylpyridine, aminopyrrolidine, indazole, pyrazole, pyrazine, pyrimidine, purine, imidazoline, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine and the like.

  The basic nitrogen-containing compound may have a substituent, and preferred substituents include amino groups (particularly unsubstituted amino groups, alkylamino groups and arylamino groups), alkyl groups (particularly unsubstituted alkyl groups and aminoalkyl groups). Group), alkoxy group, acyl group, acyloxy group, aryl group (especially unsubstituted aryl group and aminoaryl group), aryloxy group, nitro group, hydroxyl group and cyano group.

Particularly 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 1- (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- Examples include, but are not limited to, dihydroxypyrimidine, 2-pyrazoline, 3-pyrazoline, N-aminomorpholine, N- (2-aminoethyl) morpholine, trimethylimidazole, triphenylimidazole, and methyldiphenylimidazole. Absent.

  The organic basic compound (c) as an acid scavenger used in the present invention can be used alone or in combination of two or more. The usage-amount of an organic basic compound is 0.001-10 weight part normally on the basis of solid content of a positive resist composition, Preferably it is 0.01-5 weight part. From the viewpoint of the addition effect of the organic basic compound, and from the viewpoint of sensitivity and developability of the unexposed area, 0.001 to 10 parts by weight is preferable.

  Next, the solvent will be described. Preferred solvents used in the positive resist composition of the present invention include, for example, ethylene glycol monoethyl ether acetate, cyclohexanone, 2-heptanone, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether propionate, propylene Glycol monoethyl ether acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl β-methoxyisobutyrate, ethyl butyrate, propyl butyrate, methyl isobutyl ketone, ethyl acetate, isoamyl acetate, ethyl lactate, toluene, xylene, acetic acid Cyclohexyl, diacetone alcohol, N-methylpyrrolidone, N, N-dimethylformamide, γ-butyrolactone, N, N- Examples include dimethylacetamide, propylene carbonate, and ethylene carbonate.

  These solvents are used alone or in combination. The selection of the solvent is important because it affects the solubility in the positive resist composition of the present invention, the coating property to the substrate, the storage stability, and the like. Further, it is preferable that the amount of water contained in the solvent is small because it affects the performance of the resist.

  Furthermore, in the positive resist composition of the present invention, it is preferable to reduce metal impurities such as metal and impurity components such as chloro ions to 100 ppb or less. 100 ppb or less is preferable in that it does not cause a malfunction in manufacturing a semiconductor device, has no defects, and increases the yield.

  The solid content of the positive resist composition is preferably dissolved in the solvent and dissolved in a solid content concentration of 3 to 40%. More preferably, it is 5-30%, More preferably, it is 7-20%.

  In addition, the positive resist composition of the present invention is preferably used by preparing a solution with a solvent for the purpose of removing foreign substances and the like, and then usually filtering with a filter having a diameter of about 0.05 to 0.2 μm. .

  If necessary, the positive resist composition of the present invention may further include a surfactant, an acid-decomposable dissolution inhibiting compound, a dye, a plasticizer, a photosensitizer, a crosslinking agent, a photobase generator, and a thermal base generator. Further, a compound that promotes solubility in a spectral sensitizer and a developer, a compound that decreases in basicity upon exposure (photobase), and the like can be contained.

  As the surfactant that can be used in the composition of the present invention, fluorine-based and / or silicon-based surfactants are particularly preferably used. Any one or two or more of fluorine-based surfactants, silicon-based surfactants, and surfactants containing both fluorine atoms and silicon atoms can be contained. The addition of these fluorine-based and / or silicon-based surfactants is effective for suppressing development defects and improving coating properties.

As these fluorine-based and / or silicon-based surfactants, for example, JP-A-62-36663, JP-A-61-226746, JP-A-61-226745, JP-A-62-170950 are disclosed. JP-A-63-34540, JP-A-7-230165, JP-A-8-62834, JP-A-9-54432, JP-A-9-5988, JP-A-2002-277862, U.S. Pat.Nos. 5,405,720, 5,360,692, 5,529,881, 5,296,330, 5,436,098, 5,576,143, 5,294,511, 5,824,451 The following commercially available surfactants can also be used as they are.
Examples of commercially available fluorine-based and / or silicon-based 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.), Megafac 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) Fluorine-based surfactants or silicon-based surfactants such as those manufactured by K.K. 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 shown above, fluorine-based and / or silicon-based surfactants can be produced by a telomerization method (also referred to as a telomer method) or an oligomerization method (also referred to as an oligomer method). A surfactant using a polymer having a fluoroaliphatic group derived from a fluoroaliphatic compound 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 link) or poly (block link of oxyethylene and oxypropylene) 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).

For example, as a commercially available fluorine-based and / or silicon-based surfactant, Megafac F178, F-470, F-473, F-475, F-476, F-472 (manufactured by Dainippon Ink & Chemicals, Inc.) Can be mentioned. 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.

  The amount of the fluorine-based and / or silicon-based 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). Especially preferably, it is 0.01 mass%-1 mass%.

  Specific examples of surfactants that can be used other than the above include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether. , Polyoxyethylene alkyl allyl ethers such as polyoxyethylene octylphenol ether and polyoxyethylene nonylphenol ether, polyoxyethylene / polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan Sorbitan fatty acid esters such as monooleate, sorbitan trioleate, sorbitan tristearate, polyoxyethylene sorbitan Nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters such as laurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan tristearate Etc.

  The amount of these other surfactants is usually 2 parts by weight or less, preferably 1 part by weight or less per 100 parts by weight of the solid content in the composition of the present invention.

  Examples of the acid-decomposable dissolution inhibiting compound that can be used in the positive resist composition of the present invention include the low-molecular acid-decomposable dissolution inhibiting compounds described in JP-A Nos. 5-134415 and 6-51519. Can do.

  Examples of the plasticizer that can be used in the positive resist composition of the present invention are described in JP-A-4-221960, JP-A-8-262720, European Patent 735422, European Patent 416873, European Patent 439371, and US Pat. No. 5,846,690. Compounds such as di (2-ethylhexyl) adipate, n-hexyl benzoate, di-n-octyl phthalate, di-n-butyl phthalate, benzyl n-butyl phthalate, dihydroabiethyl phthalate Etc.

  Examples of the compound that promotes the solubility in the developer that can be used in the present invention include JP-A-4-134345, JP-A-4-217251, JP-A-7-181680, JP-A-8-211597, and US Pat. No. 5,688,628. Polyhydroxy compounds described in U.S. Pat. No. 5,972,559, and the like. 1,1-bis (4-hydroxyphenyl) cyclohexane, 4,4- (α-methylbenzylidene) bisphenol, α, α ′, α ″ -tris ( 4-hydroxyphenyl) -1,3,5-triisopropylbenzene, α, α ′, α ″ -tris (4-hydroxyphenyl) -1-ethyl-4-isopropylbenzene, 1,2,2-tris (hydroxy Phenyl) propane, 1,1,2-tris (3,5-dimethyl-4-hydroxyphenyl) propane, 2,2 5,5-tetrakis (4-hydroxyphenyl) hexane, 1,2-tetrakis (4-hydroxyphenyl) ethane, 1,1,3-tris (hydroxyphenyl) butane, para [α, α, α ′, α ′ Aromatic polyhydroxy compounds such as -tetrakis (4-hydroxyphenyl)]-xylene are preferably used.

  Organic acids such as salicylic acid, diphenolic acid, and phenolphthalein can also be used, and sulfonamide compounds described in JP-A-5-181263 and 7-92680, JP-A-4-248554, and Alkali-soluble resins such as carboxylic acids and carboxylic acid anhydrides described in JP-A-5-181279 and 7-92679, and polyhydroxystyrene resins described in JP-A No. 11-153869 can also be added.

  Suitable dyes that can be used in the present invention include oil-based 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.

  Further, the composition of the present invention includes ammonium salts described in JP-A-7-28247, European Patent 616258, US Pat. No. 5,525,443, JP-A-9-127700, European Patent 762207, and US Pat. No. 5,783,354. Can be added tetramethylammonium hydroxide, tetra-n-butylammonium hydroxide, betaine, etc., and JP-A-5-232706, 6-11835, 6-242606, 6-266100, A compound (photobase) whose basicity is lowered by exposure described in JP-A-7-333851, JP-A-7-333844, US Pat. No. 5,663,035 and European Patent No. 6777788 can also be added.

Further, by adding a spectral sensitizer as listed below, the photoacid generator used is sensitized to a longer wavelength region than far ultraviolet, which has no absorption, whereby the positive resist composition of the present invention is i-lined. Or sensitivity can be given to g line. Specific examples of suitable spectral sensitizers include benzophenone, p, p′-tetramethyldiaminobenzophenone, p, p′-tetraethylethylaminobenzophenone, 2-chlorothioxanthone, anthrone, 9-ethoxyanthracene, anthracene, Pyrene, perylene, phenothiazine, benzyl, acridine orange, benzoflavin, cetoflavin-T, 9,10-diphenylanthracene, 9-fluorenone, acetophenone, phenanthrene, 2-nitrofluorene, 5-nitroacenaphthene, benzoquinone, 2-chloro- 4-nitroaniline, N-acetyl-p-nitroaniline, p-nitroaniline, N-acetyl-4-nitro-1-naphthylamine, picramide, anthraquinone, 2-ethylanthraquinone, 2-tert-butyl Tyranthraquinone, 1,2-benzanthraquinone, 3-methyl-1,3-diaza-1,9-benzanthrone, dibenzalacetone, 1,2-naphthoquinone, 3,3′-carbonyl-bis (5 7-dimethoxycarbonylcoumarin) and coronene, but are not limited thereto.

  These spectral sensitizers can also be used as a light absorber for far ultraviolet light as a light source. In this case, the light absorber can reduce the standing wave by reducing the reflected light from the substrate and reducing the influence of multiple reflection in the resist film.

  Examples of the photobase generator that can be added to the composition of the present invention include JP-A-4-151156, JP-A-4-162040, JP-A-5-197148, JP-A-5-5995, JP-A-6-194634, and JP-A-8-146608. No. 10-83079 and European Patent No. 622682, specifically, 2-nitrobenzyl carbamate, 2,5-dinitrobenzyl cyclohexyl carbamate, N-cyclohexyl-4-methylphenylsulfonamide 1,1-dimethyl-2-phenylethyl-N-isopropylcarbamate and the like can be preferably used. These photobase generators are added for the purpose of improving the resist shape and the like.

  Examples of the thermal base generator include compounds described in JP-A-5-158242, 5-158239, and US Pat. No. 5,576,143.

  The positive resist composition of the present invention is preferably pre-coated on a substrate (eg, silicon / silicon dioxide coating), glass, ceramics, metal, or the like as used in the manufacture of precision integrated circuit elements. It is used as a two-layer resist applied on the lower layer resist.

  An appropriate organic polymer film is used as the lower layer resist, but various known photoresists may be used. For example, each series of the Fuji Film Arch FH series, FHi series, or Sumitomo Chemical PFI series can be illustrated.

This layer is formed by dissolving the compound contained in the first resist layer in an appropriate solvent and applying the resulting solution by a spin coating method, a spray method or the like. The film thickness of the first resist layer is usually 0.1 to 4.0 μm, preferably 0.1 to 2.0 μm, more preferably 0.2 to 1.5 μm, and particularly preferably 0. .25 to 1.2 μm. From the viewpoint of antireflection and dry etching resistance, it is preferably 0.1 μm or more, and preferably 4.0 μm or less from the viewpoint of aspect ratio and retention of the formed fine pattern.

  Next, the second resist layer is formed, but before that, the first resist layer is preferably heat-treated. As temperature of heat processing, 150-250 degreeC is preferable, Furthermore, 170-240 degreeC is preferable, and 180-230 degreeC is especially preferable. In view of preventing intermixing of the first resist layer and the second resist layer and decomposition degradation of the polymer in the first resist, 150 ° C. to 250 ° C. is preferable. This heat treatment can be performed using an apparatus such as a hot plate or a heat oven.

  Moreover, although the heat processing time changes with the said heat processing temperature, in the case of 180-230 degreeC heat processing, it is preferable to set to the range of 10 second-1000 second, and also 20-600 second is preferable. From the viewpoint of preventing intermixing between the first resist layer and the second resist layer, and from the viewpoint of increasing the number of processed substrates, it is preferably 10 seconds to 1000 seconds.

Next, a second resist layer is formed on the first resist layer, and the compounds of components (a) to (c) of the positive resist composition are dissolved in a solvent, and the obtained solution is spin-coated. The coating is performed by spraying or the like.
The film thickness of the second resist layer is preferably 0.03 to 0.6 μm, more preferably 0.04 to 0.5 μm, and particularly preferably 0.05 to 0.45 μm. From the viewpoints of pattern transfer to the first resist layer, prevention of pinholes in the coating film, and lithography performance, 0.03 μm to 0.6 μm is preferable.

  The obtained two-layer resist is then subjected to a pattern formation step. As a first step, the second layer resist composition is first subjected to pattern formation processing. Mask alignment is performed as necessary, and actinic rays or radiation is irradiated through the mask, so that the resist composition in the irradiated portion is made soluble in an alkaline aqueous solution and developed with an alkaline aqueous solution to form a pattern.

  The developer for the second resist layer used in the present invention includes inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine and the like. Primary amines, secondary amines such as diethylamine and di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, tetraethyl An aqueous solution of an alkali such as a quaternary ammonium salt such as ammonium hydroxide, or a cyclic amine such as pyrrole or piperidine can be used.

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.

  Furthermore, an appropriate amount of alcohol, surfactant, aromatic hydroxyl group-containing compound or the like can be added to the alkaline aqueous solution. Of these, tetramethylammonium hydroxide is most preferably used.

  Next, dry etching is performed as a second stage, and this operation is performed by oxygen plasma etching using the resist composition film pattern as a mask to form a fine pattern having a high aspect ratio. The etching of the organic polymer film by the oxygen plasma etching is exactly the same technique as the plasma etching used when the resist film is peeled off after completion of the etching process of the substrate by the conventional photoetching operation. This operation can be performed, for example, by a cylindrical plasma etching apparatus using oxygen as a reactive gas, that is, an etching gas. A gas such as sulfurous acid gas may be mixed with oxygen gas.

  Examples and Comparative Examples are shown below, but the present invention is not limited to the following Examples.

<Synthesis example of acid generator>
Synthesis Example (1) Synthesis of Compound (I-2) 10 g of mesityl oxide was dissolved in 100 ml of N, N-dimethylformamide, and 50 ml of triethylamine was added thereto. To this solution, 22.1 g of trimethylsilyl chloride was added and reacted at 100 ° C. for 2 hours. After cooling, 300 ml of hexane was added, and the mixture was washed twice with a saturated aqueous sodium hydrogen carbonate solution and twice with distilled water. Concentration of the organic phase gave a crude product. When this was produced by distillation under reduced pressure (78 ° C./15 mmHg), silyl enol ether of mesityl oxide was obtained. 5 g of the obtained silyl enol ether and 3.1 g of tetramethylene sulfoxide were dissolved in 50 ml of chloroform, and this solution was cooled to -30 ° C. To this, 9.9 g of trifluoroacetic anhydride was added dropwise over 30 minutes. After the reaction for 2 hours, 10 g of potassium nonafluorobutanesulfonate was dissolved in acetonitrile / water and added. The mixture was washed with water and the chloroform phase was concentrated. The obtained crude product was washed with diisopropyl ether to obtain 4.2 g of compound (I-2).

300 MHz ¹ H-NMR (CDCl ₃ )
δ 1.95 (s. 3H), δ 2.2 (s. 3H), δ 2.2 to 2.5 (m. 4H), δ 3.5 to 3.7 (m. 4H), δ 4.75 (s. 2H), δ6.2 (t.1H)

Synthesis Example (2) Synthesis of Compound (I-26) 20 g of 2-cyclohexen-1-one was dissolved in 300 ml of N, N-dimethylformamide, and 150 ml of triethylamine was added thereto. To this solution, 45 g of trimethylsilyl chloride was added and reacted at 100 ° C. for 2 hours. After allowing to cool, 500 ml of hexane was added, and the mixture was washed twice with a saturated aqueous sodium hydrogen carbonate solution and twice with distilled water.
Concentration of the organic phase gave a crude product. When this was produced by distillation under reduced pressure (86 ° C./15 mmHg), silyl enol ether of 2-cyclohexen-1-one was obtained. The resulting silyl enol ether of 2-cyclohexen-1-one and 3.1 g of tetramethylene sulfoxide were dissolved in 100 ml of chloroform, and this solution was cooled to -30 ° C. To this was added dropwise 6.24 g of trifluoroacetic anhydride over 30 minutes. After the reaction for 2 hours, 10 g of potassium nonafluorobutanesulfonate was dissolved in acetonitrile / water and added. The mixture was washed with water and the chloroform phase was concentrated. The obtained crude product was recrystallized from ethyl acetate / diisopropyl ether (40/60) to obtain 3.7 g of compound (I-26).

300 MHz ¹ H-NMR (CDCl ₃ )
δ2.1 to 2.3 (m.3H), δ2.5 to 2.8 (s.4H), δ3.05 (m.1H), δ3.45 (m.1H), δ3.8 (m. 2H), δ3.9 (m.1H), δ5.3 (m.1H), δ6.2 (dd.1H), δ7.25 (d.1H)

Synthesis Example (3) Synthesis of Compound (IA-32) 23.8 g of isophorone was dissolved in 100 ml of acetonitrile, and 20.9 g of triethylamine and 31.0 of sodium iodide were added thereto. To this solution, 22.5 g of trimethylsilyl chloride was slowly added and reacted at 60 ° C. for 2 hours. After allowing to cool, the reaction solution was poured onto ice and extracted with diisopropyl ether, and the organic phase was washed twice with a saturated aqueous sodium hydrogen carbonate solution and twice with distilled water. Concentration of the organic phase gave a crude product. When this was purified by distillation under reduced pressure (108 ° C./15 mmHg), enol silyl ether from which hydrogen at the allylic position of isophorone was eliminated was obtained. The obtained enol silyl ether (15 g) and tetramethylene sulfoxide (7.5 g) were dissolved in chloroform (100 ml), and the solution was cooled to -30 ° C. To this, 15.0 g of trifluoroacetic anhydride was added dropwise over 30 minutes. After the reaction for 2 hours, 24 g of potassium nonafluorobutanesulfonate was dissolved in acetonitrile / water and added. The mixture was washed with water and the chloroform phase was concentrated. The obtained crude product was washed with diisopropyl ether to obtain a powder. This was recrystallized from ethyl acetate / diisopropyl ether to obtain 20 g of Compound (IA-32).

300 MHz ¹ -NMR (CDCl ₃ )
δ1.2 (s.6H), δ1.75 (s.3H), δ2.3 (s.2H), δ2.4 (s.2H), δ2.3 to 2.6 (m.4H), δ3 .4 to 3.8 (m.4H), .delta.4.2 (s.2H), .delta.6.2 (s.1H)

  Other compounds were synthesized using the same method.

<Example of resin synthesis>
Synthesis Example 4 (Synthesis of Resin 9)
After adding 10.4 g of trimethylallylsilane, 9.8 g of maleic anhydride, and 5.3 g of t-butyl acrylate to 34 g of dry THF, the mixture was heated to 65 ° C. under a nitrogen stream. When the reaction temperature was stabilized, Wako Pure Chemical Industries, Ltd. Initiator V-65 was added at 10 mol% of the total number of moles of the monomers to initiate the reaction. After reacting for 6 hours, the reaction mixture was diluted twice with THF and then poured into a large amount of hexane to precipitate a white powder. Next, in order to reduce residual monomers and low molecular components, the precipitated powder was dissolved in acetone, and then hexane was gradually added thereto to precipitate the polymer. The precipitated polymer was washed with hexane / acetone (8/2) and dried under reduced pressure to obtain a resin (9). As a result of GPC measurement, the molecular weight of the obtained resin (9) was 5600 in terms of weight average using polystyrene as a standard sample, and the content of components having a molecular weight of 1000 or less was 4% in terms of the area ratio of GPC.

  Resins (1) to (19) were obtained in the same manner as above.

Synthesis Example 5 (Synthesis of Resin 22)
Monomer synthesis 29.1 g of tris (trimethylsilyl) -2-hydroxyethylsilane was added to 200 ml of the lower layer THF, and 11.2 g of 4-dimethylaminopyridine was added thereto. After the reaction solution was cooled to 0 ° C., 14.0 g of acrylic acid chloride was added dropwise thereto over 1 hour. After the reaction solution was allowed to react for 5 hours while returning the reaction solution to room temperature, the reaction solution was concentrated under reduced pressure, and then an acrylate monomer was obtained by silica gel column chromatography.
Polymer Synthesis 9.5 g of maleic anhydride and 3.8 g of methacrylic acid were dissolved in 18.0 g of this acrylate monomer in THF to prepare a solution having a solid content of 50%. This was charged into a three-necked flask and heated to 60 ° C. under a nitrogen stream. When the reaction temperature was stabilized, 5 mol% of initiator V-60 manufactured by Wako Pure Chemical Industries, Ltd. was added to initiate the reaction. After reacting for 6 hours, the reaction mixture was diluted 2-fold with THF and poured into a large amount of hexane to precipitate a white solid. The precipitated powder was filtered out and dried to obtain Resin (22). As a result of GPC measurement, the molecular weight of the obtained resin (22) was 6900 in terms of weight average using polystyrene as a standard sample.

  Resins (20) to (35) were obtained in the same manner as above.

Examples 1-13
(1) Formation of Lower Resist Layer FHi-028DD resist (resist for i-line manufactured by Fujifilm Orin) is applied to a 6-inch silicon wafer using a spin coater Mark8 manufactured by Tokyo Electron, and baked at 90 ° C. for 90 seconds. A uniform film of 0.55 μm was obtained.

This was further heated at 200 ° C. for 3 minutes to obtain a lower resist layer having a thickness of 0.40 μm.
(2) Formation of upper resist layer An upper resist solution having the composition shown in Tables 1 and 2 was prepared, and the obtained solution was microfiltered with a membrane filter having a 0.1 μm aperture to obtain a second resist composition. Got. In addition, the ratio at the time of using 2 types of solvents in Table-1 and Table-2 is a weight ratio.

  On the first resist layer, the upper resist composition was similarly applied and heated at 130 ° C. for 90 seconds to obtain an upper resist layer having a thickness of 0.20 μm.

  The wafer thus obtained was exposed to an ArF excimer stepper 9300 manufactured by ISI with a resolving power mask while changing the exposure amount.

Then, after heating at 120 ° C. for 90 seconds in a clean room, the film was developed with a tetrahydroammonium hydroxide developer (2.38 wt%) for 60 seconds, rinsed with distilled water and dried to obtain a pattern (upper layer pattern). Further, the wafer having the upper layer pattern was etched (dry development) using a parallel plate type reactive ion etching apparatus DES-245R manufactured by Plasma System, and a pattern was formed on the lower layer. The etching gas was oxygen, the pressure was 20 mTorr, and the applied power was 100 mW / cm ² . The formed resist pattern was observed with a scanning electron microscope.

The sensitivity, resolution, and etching resistance were evaluated by the following methods.
(1) Sensitivity: Sensitivity is shown as an exposure amount for reproducing a 0.15 μm mask pattern.
(2) Resolving power: The resolving power is indicated by the limiting resolving power at an exposure amount for reproducing a mask pattern of 0.15 μm.
(3) Etching resistance: Etching resistance was expressed as a relative ratio of etching rate to polyhydroxystyrene. A value of 1.0 or more and less than 1.2 was evaluated as good (◯), a value of 1.2 or more and less than 1.5 was permitted (Δ), and a value of 1.5 or more was determined as unacceptable (x).

  The acid generator, acid scavenger, surfactant and solvent used here are shown below.

As an acid generator used in the comparative example,
(B-1): Triphenylsulfonium-trifluoromethanesulfonate (b-2): Tri (t-butylphenyl) sulfonium-perfluorobutanesulfonate.
As an acid supplement,
(C-1): 1,5-diazabicyclo [4.3.0] -5-nonene (C-2): 1,8-diazabicyclo [5.4.0] -7-undecene (C-3): Represents 2-phenylbenzimidazole.

As surfactant,
Fluorosurfactant (W-1): Megafac F176 (Dainippon Ink Co., Ltd.)
Fluorine / silicone surfactant (W-2): Megafac R08 (Dainippon Ink Co., Ltd.)
Silicon-based surfactant (W-3): polysiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.)
Fluorosurfactant (W-4): Fluorad FC430 (manufactured by Sumitomo 3M Limited)
Represents.

As a solvent,
(S-1): Methoxypropyl acetate (S-2): 2-methoxypropanol (S-3): represents ethyl lactate.

Comparative Example 1
In the composition of Example 1, a resist composition was prepared, applied, exposed, developed, and etched in the same manner as in Example 1 except that (I-1) was not used as the acid generator. Evaluation similar to 1 was performed. The results are shown in Table 1.

Comparative Example 2
In the composition of Example 3, a resist composition was prepared, applied, exposed, developed, and etched in the same manner as in Example 3 except that (I-8) was not used as the acid generator. Evaluation similar to 3 was performed. The results are shown in Table 1.

Examples 14-17
In Example 1, KrF excimer stepper FPA3000EX-5 manufactured by Canon was used instead of ArF excimer stepper 9300 manufactured by ISI. Further, a resist composition was prepared, applied, exposed, and exposed in the same manner as in Example 1 except that the resin, acid generator, acid scavenger, surfactant and solvent in Example 1 were changed to those shown in Table 1. Development and etching were performed, and the same evaluation as in Example 1 was performed. The results are shown in Table 1. In this case, however, the evaluation was performed using a 0.18 μm contact hole pattern.
Comparative Example 3
In the composition of Example 14, a resist composition was prepared, applied, exposed, developed, and etched in the same manner as in Example 14 except that (I-8) was not used as the acid generator. Evaluation similar to 14 was performed. The results are shown in Table 1.
Comparative Example 4
In the composition of Example 15, a resist composition was prepared, applied, exposed, developed, and etched in the same manner as in Example 15 except that (I-16) was not used as the acid generator. Evaluation similar to 15 was performed. The results are shown in Table 1.

  From the evaluation results of Examples 1 to 13 and Comparative Examples 1 and 2, and the evaluation results of Examples 14 to 17 and Comparative Examples 3 to 4, the following is clear.

  That is, the examples of the positive silicon-containing resist composition of the present invention are superior in sensitivity, higher in resolution, and excellent in etching resistance than the comparative examples.

  A positive silicon-containing resist composition for exposure by irradiation with actinic rays or radiation such as ultraviolet rays, far-ultraviolet rays, X-rays, electron beams, molecular rays, γ rays, synchrotron radiation, etc., and further a process for producing semiconductors such as ICs For example, it can be applied when manufacturing a circuit board or the like. In particular, it can be applied as a positive silicon-containing resist composition for microfabrication which gives a resist having a high resolution and sensitivity, a rectangular cross-sectional shape and has a wide process tolerance.

Claims (1)

(A) a polymer having a silicon atom in the side chain and insoluble or hardly soluble in an alkaline aqueous solution, and soluble in an alkaline aqueous solution by the action of an acid; and (b) an acid generated upon irradiation with actinic rays or radiation. A positive resist composition comprising a compound represented by the following general formula (I) or (II):

In general formulas (I) and (II),
R _{1 to} R ₃ may be the same or different and each represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, or an alkoxy group.
R ₄ and R ₅ may be the same or different and each represents a hydrogen atom, a cyano group, an alkyl group, an aryl group, or an alkoxy group.
Y ₁ and Y ₂ may be the same or different and each represents an alkyl group, an aryl group, an aralkyl group or an aromatic group containing a hetero atom.
m represents an integer of 1 to 4. When m is 2 or more, a plurality of R ₁ and R ₂ may be the same or different.
Any two or more of R _{1 to} R ₃ , R ₄ , R ₅ , Y ₁ and Y ₂ may be bonded to form a ring structure.
In addition, at any position of R _{1 to} R ₃ , R ₄ , R ₅ , Y ₁ and Y ₂ , they are bonded via a linking group and have two or more structures of the general formula (I) or (II). You may do it.
X ⁻ represents a non-nucleophilic anion.