JP4070521B2 - Positive resist composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive resist composition which prevents falling of a pattern and ensures improved edge roughness, density dependence and surface roughness in etching. <P>SOLUTION: The positive resist composition comprises a resin containing a repeating unit having a dihydroxy- or trihydroxyadamantyl group and a repeating unit having an acid-decomposable alicyclic group at a specified composition molar ratio and capable of increasing the velocity of dissolution in an alkali developer by the action of an acid and a compound capable of generating an acid upon irradiation with an actinic ray or a radiation. <P>COPYRIGHT: (C)2003,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a positive resist composition used in an ultramicrolithography process such as the manufacture of VLSI and high-capacity microchips and other photofabrication processes.
[0002]
[Prior art]
In recent years, the degree of integration of integrated circuits has been increasing, and in the manufacture of semiconductor substrates such as VLSI, processing of ultrafine patterns having a line width of less than half a micron has been required. In order to satisfy this need, the operating wavelength of an exposure apparatus used for photolithography has been increasingly shortened, and now it is considered to use excimer laser light (XeCl, KrF, ArF, etc.) having a short wavelength among far ultraviolet rays. It is becoming.
A chemical amplification type resist is used for lithography pattern formation in this wavelength region.
[0003]
In general, chemically amplified resists can be broadly classified into three types, commonly called two-component systems, 2.5-component systems, and three-component systems. The two-component system combines a compound that generates an acid by photolysis (hereinafter referred to as a photoacid generator) and a binder resin. The binder resin is a resin having in its molecule a group (also referred to as an acid-decomposable group) that decomposes by the action of an acid and increases the solubility of the resin in an alkaline developer. The 2.5 component system further contains a low molecular weight compound having an acid-decomposable group in the two component system. A three-component system contains a photoacid generator, an alkali-soluble resin, and the low molecular weight compound.
[0004]
The chemical amplification resist is suitable as a photoresist for irradiation with ultraviolet rays or far ultraviolet rays, but among them, it is necessary to cope with the required characteristics in use.
As a photoresist composition for an ArF light source, a resin in which an alicyclic hydrocarbon moiety is introduced has been proposed for the purpose of imparting dry etching resistance, but the system is extremely hydrophobic as an adverse effect of the introduction of the alicyclic hydrocarbon moiety. Therefore, it is difficult to develop with a tetramethylammonium hydroxide (hereinafter, TMAH) aqueous solution that has been widely used as a resist developer, and the resist is peeled off from the substrate during development. It can be seen.
In response to the hydrophobization of the resist, measures such as mixing an organic solvent such as isopropyl alcohol with the developer have been studied, and although some results are seen, the concern about the swelling of the resist film and the process become complicated. The problem is not necessarily solved. In the approach of improving the resist, many measures have been taken to supplement various hydrophobic alicyclic hydrocarbon sites by introducing hydrophilic groups.
[0005]
On the other hand, JP-A-11-109632 describes that a resin containing a polar group-containing alicyclic functional group and an acid-decomposable group is used for the radiation-sensitive material. Japanese Patent No. 3042618 describes a photoresist composition containing a polymer obtained by copolymerizing a (meth) acrylate derivative having a lactone structure with another polymerizable compound.
[0006]
As described above, a resin containing an acid-decomposable group used for a photoresist for exposure to deep ultraviolet rays generally contains an aliphatic cyclic hydrocarbon group in the molecule at the same time. For this reason, the resin became hydrophobic, and there were problems due to it. Various means as described above for improving it have been studied. However, the above technique still has insufficient points, and improvement is desired.
[0007]
Japanese Patent Application Laid-Open No. 2001-109154 discloses a positive photoresist composition having high sensitivity, high resolution, and improved pattern edge roughness by using a copolymer resin of an alicyclic lactone monomer and a monohydroxyadamantane monomer. However, the problem of pattern collapse and surface roughness during etching were not sufficiently improved. Here, “pattern collapse” means that the pattern collapses so that the pattern is folded near the substrate interface or the like when the line pattern is formed.
[0008]
Furthermore, Japanese Patent Application Laid-Open Nos. 2000-338664 and 2001-183836 describe resist compositions containing a copolymer resin of a dihydroxyadamantane monomer and an acid-decomposed adamantane monomer. The surface roughness at the time, as well as edge roughness and density dependence were still not sufficiently improved.
[0009]
[Problems to be solved by the invention]
Therefore, the object of the present invention can be suitably used in ultra-microlithography processes such as the manufacture of VLSI and high-capacity microchips and other photofabrication processes, and prevents pattern collapse, edge roughness, and density. It is an object of the present invention to provide a positive resist composition having improved dependency and surface roughness during etching.
[0010]
[Means for Solving the Problems]
As a result of intensive studies on the constituent materials of the positive chemical amplification resist composition, the present inventors have achieved the object of the present invention by using an acid-decomposable resin containing a specific repeating unit at a specific ratio. As a result, the present invention has been achieved.
That is, the above object is achieved by the following configuration.
[0011]
(1) (A) At least a repeating unit A1 having a dihydroxyadamantyl group or a trihydroxyadamantyl group, a repeating unit A2 having an acid-decomposable alicyclic group , and the following general formulas (V-1) to (V-4) A resin containing a repeating unit A3 having a group represented by any of the above as a constituent unit, a resin whose dissolution rate in an alkali developer increases by the action of an acid, and (B) a compound that generates an acid upon irradiation with actinic rays or radiation The compositional molar ratio A1 / A2 of the repeating unit A1 and the repeating unit A2 in the resin (A) is 0.15 or more and 1.0 or less, and the resin (A The positive resist composition is characterized in that the total content of the repeating unit A1 and the repeating unit A2 is 40 to 70 mol%.
[Formula 4]
In General Formulas (V-1) to (V-4), R _{1b to} R _5b each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, or an alkenyl group that may have a substituent. Two of R _{1b to} R _5b may combine to form a ring.
(2) The composition according to (1), wherein A1 / A2 is 0.35 or more and 1.0 or less.
(3) The composition according to (1) or (2), wherein the repeating unit A1 having a dihydroxyadamantyl group or a trihydroxyadamantyl group is a repeating unit represented by the following general formula (I).
[Chemical formula 5]
In the general formula (I), R ₁ represents a hydrogen atom, an alkyl group, a halogen atom or a cyano group, and R ₂ represents a hydrogen atom or a hydroxyl group.
(4) The repeating unit A2 having an acid-decomposable alicyclic group is selected from the group of repeating units having a partial structure containing an alicyclic hydrocarbon represented by the following general formula (pI) to general formula (pVI). The composition according to any one of (1) to (3).
[Chemical 6]
(Wherein R ₁₁ represents a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group or a sec-butyl group, and Z represents an alicyclic hydrocarbon group together with a carbon atom. Represents the atomic group necessary to form.
R _{12 to} R ₁₆ each independently represents a linear or branched alkyl group or alicyclic hydrocarbon group having 1 to 4 carbon atoms, provided that at least one of R _{12 to} R ₁₄ , or Either R ₁₅ or R ₁₆ represents an alicyclic hydrocarbon group.
R _{17 to} R ₂₁ each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or an alicyclic hydrocarbon group, provided that at least one of R _{17 to} R ₂₁ Represents an alicyclic hydrocarbon group. Further, either R ₁₉ or R ₂₁ represents a linear or branched alkyl group or alicyclic hydrocarbon group having 1 to 4 carbon atoms.
R _{22 to} R ₂₅ each independently represents a linear or branched alkyl group having 1 to 4 carbon atoms or an alicyclic hydrocarbon group, provided that at least one of R _{22 to} R ₂₅ is a fat Represents a cyclic hydrocarbon group. R ₂₃ and R ₂₄ may be bonded to each other to form a ring. )
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the components used in the present invention will be described in detail.
[1] (A) A resin (also referred to as “acid-decomposable resin”) whose dissolution rate in an alkaline developer is increased by the action of an acid.
[0013]
In the present invention, the repeating unit A1 having a dihydroxyadamantyl group or a trihydroxyadamantyl group is preferably a repeating unit represented by the above general formula (I).
[0014]
In general formula (I), examples of the alkyl group represented by R ₁ include linear and branched alkyl groups, which may have a substituent.
The linear or branched alkyl group is preferably a linear or branched alkyl group having 1 to 12 carbon atoms, more preferably a linear or branched alkyl group having 1 to 10 carbon atoms. More preferably, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl It is a group.
[0015]
In general formula (I), examples of the halogen atom represented by R ₁ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
[0016]
The acid-decomposable alicyclic group in the present invention is a structural unit for protecting an alkali-soluble group with a residue that can be removed under acidic conditions, and the residual protective group after deprotection includes an alicyclic structure. Is. Examples of the alkali-soluble group include carboxylic acid, sulfonic acid, sulfonamide, N-sulfonylimide, disulfonylimide and the like, and carboxyl group is particularly preferable from the viewpoint of transmittance and exposure margin. Examples of the alicyclic group include the cyclic hydrocarbon structures described below.
[0017]
In the present invention, the repeating unit A2 having an acid-decomposable alicyclic group is preferably selected from the group of repeating units having a partial structure containing an alicyclic hydrocarbon represented by the above general formula (pI) to general formula (pVI). Is to be selected.
[0018]
In the general formulas (pI) to (pVI), the alkyl group in R _{12 to} R ₂₅ may be substituted or unsubstituted, and is a linear or branched alkyl group having 1 to 4 carbon atoms. Represents. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a t-butyl group. Further, the further substituent of the alkyl group includes an alkoxy group having 1 to 4 carbon atoms, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an acyl group, an acyloxy group, a cyano group, a hydroxyl group, A carboxy group, an alkoxycarbonyl group, a nitro group, etc. can be mentioned.
[0019]
The alicyclic hydrocarbon group in R _{11 to} R _{25 or} the alicyclic hydrocarbon group formed by Z and a carbon atom may be monocyclic or polycyclic. Specific examples include groups having a monocyclo, bicyclo, tricyclo, tetracyclo structure or the like having 5 or more carbon atoms. The carbon number is preferably 6-30, and particularly preferably 7-25. These alicyclic hydrocarbon groups may have a substituent.
Below, the structural example of an alicyclic part is shown among alicyclic hydrocarbon groups.
[0020]
[Chemical 7]
[0021]
[Chemical 8]
[0022]
[Chemical 9]
[0023]
In the present invention, preferred examples of the alicyclic moiety include an adamantyl group, a noradamantyl group, a decalin residue, a tricyclodecanyl group, a tetracyclododecanyl group, a norbornyl group, a cedrol group, a cyclohexyl group, and a cycloheptyl group. A group, a cyclooctyl group, a cyclodecanyl group, and a cyclododecanyl group. More preferred are an adamantyl group, a decalin residue, a norbornyl group, a cedrol group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecanyl group, and a cyclododecanyl group.
[0024]
Examples of the substituent for these alicyclic hydrocarbon groups include an alkyl group, a substituted alkyl group, a halogen atom, a hydroxyl group, an alkoxy group, a carboxyl group, and an alkoxycarbonyl group. 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 a substituent selected from the group consisting of a methyl group, an ethyl group, a propyl group, and an isopropyl group. To express. Examples of the substituent of the substituted alkyl group include a hydroxyl group, a halogen atom, and an alkoxy 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.
[0025]
The structures represented by the general formulas (pI) to (pVI) in the resin can be used for protecting alkali-soluble groups. Examples of the alkali-soluble group include various groups known in this technical field.
Specific examples include carboxylic acid, sulfonic acid, sulfonamide, N-sulfonylimide, disulfonylimide and the like, and carboxyl group is particularly preferable from the viewpoint of transmittance and exposure margin.
Preferred examples of the alkali-soluble group protected by the structure represented by the general formulas (pI) to (pVI) in the resin include groups represented by the following general formulas (pVII) to (pXI).
[0026]
[Chemical Formula 10]
[0027]
Here, R _{11 to} R ₂₅ and Z are the same as defined above.
In the resin, the repeating unit having an alkali-soluble group protected by the structure represented by the general formulas (pI) to (pVI) is preferably a repeating unit represented by the following general formula (pA).
[0028]
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[0029]
Here, R represents a hydrogen atom, a halogen atom, or a substituted or unsubstituted linear or branched alkyl group having 1 to 4 carbon atoms. A plurality of R may be the same or different.
A represents a single bond or a divalent linking group. The divalent linking group may be selected from the group consisting of an alkylene group, a substituted alkylene group, an ether group, a thioether group, a carbonyl group, an ester group, an amide group, a sulfonamide group, a urethane group, or a urea group, or 2 Represents a combination of two or more groups.
R _a represents any group of the above formulas (pI) to (pVI).
[0030]
Specific examples of the monomer corresponding to the repeating unit represented by the general formula (pA) are shown below.
[0031]
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[0032]
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[0033]
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[0034]
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[0035]
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[0036]
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[0037]
In the acid-decomposable resin (A) of the present invention, the composition molar ratio A1 / A2 of the repeating unit A1 having a dihydroxyadamantyl group or trihydroxyadamantyl group and the repeating unit A2 having an acid-decomposable alicyclic group is 0.15 or more. 1.0 or less, preferably 0.35 or more and 1.0 or less, and the total content of A1 and A2 needs to be 40 to 70 mol%. When the composition ratio A1 / A2 is less than 0.15, the pattern collapse prevention property and the surface roughness prevention property during etching deteriorate. In addition, A1 / A2 is preferably 0.35 or more from the viewpoint of further improving the prevention of pattern collapse and the prevention of surface roughness during etching, and further satisfying edge roughness and density dependency. On the other hand, if it exceeds 1.0, the pattern collapse prevention property deteriorates, which is not preferable. In addition, when the total content of A1 and A2 is less than 40 mol%, resolution and edge roughness deteriorate, and even when it exceeds 70 mol%, the dependency on density / dense, the roughness of the surface during etching, and This is not preferable because the pattern collapse prevention property deteriorates. More preferably, the ratio of A1 / A2 is 0.4 or more and 0.8 or less. On the other hand, the total content of A1 and A2 is more preferably 45 to 65 mol%. Moreover, it is more preferable that A1 / A2 is 0.4 or more and 0.8 or less, and the total content of A1 and A2 is 45 to 65 mol%.
[0038]
The acid-decomposable resin (A) of the present invention preferably further contains an alicyclic lactone repeating unit A3 as a constituent unit in the repeating units A1 and A2. As the alicyclic lactone repeating unit A3, a repeating unit having a group represented by any one of the general formulas (V-1) to (V-4) and a repeating unit having a group represented by the general formula (VI). Can be mentioned. The alicyclic lactone repeating unit is preferable from the viewpoint of pattern collapse and etching surface roughness as compared with a repeating unit having a general lactone residue. The content of the alicyclic lactone repeating unit is preferably from 5 to 65 mol%, more preferably from 10 to 60 mol%, still more preferably from 15 to 55 mol%. Furthermore, among the alicyclic lactone repeating units, a repeating unit having a group represented by any one of the general formulas (V-1) to (V-4) is preferable from the viewpoint of pattern collapse.
[0039]
In General Formulas (V-1) to (V-4), R _{1b to} R _5b each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, or an alkenyl group that may have a substituent. Two of R _{1b to} R _5b may combine to form a ring.
[0040]
In the general formulas (V-1) to (V-4), examples of the alkyl group in R _{1b to} R _5b include linear and branched alkyl groups, which may have a substituent.
The linear or branched alkyl group is preferably a linear or branched alkyl group having 1 to 12 carbon atoms, more preferably a linear or branched alkyl group having 1 to 10 carbon atoms. More preferably, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl It is a group.
[0041]
As a cycloalkyl group in R _<1b > -R < _5b >, C3-C8 things, such as a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, are preferable.
As an alkenyl group in R _<1b > -R < _5b >, C2-C6 things, such as a vinyl group, a propenyl group, a butenyl group, a hexenyl group, are preferable.
Examples of the ring formed by combining two of R _{1b to} R _5b include 3- to 8-membered rings such as a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, and a cyclooctane ring.
In the general formulas (V-1) to (V-4), R _{1b to} R _5b may be connected to any carbon atom constituting the cyclic skeleton.
[0042]
Moreover, as a preferable substituent which the said alkyl group, a cycloalkyl group, and an alkenyl group may have, a C1-C4 alkoxy group, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), Examples thereof include an acyl group having 2 to 5 carbon atoms, an acyloxy group having 2 to 5 carbon atoms, a cyano group, a hydroxyl group, a carboxy group, an alkoxycarbonyl group having 2 to 5 carbon atoms, and a nitro group.
[0043]
Examples of the repeating unit having a group represented by general formulas (V-1) to (V-4) include a repeating unit represented by the following general formula (AI).
[0044]
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[0045]
In general formula (AI), R _b0 represents a hydrogen atom, a halogen atom, or a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms. As a preferable substituent which the alkyl group of R _b0 may have, as a preferable substituent which the alkyl group as R _1b in the general formulas (V-1) to (V-4) may have. What was illustrated previously is mentioned.
Examples of the halogen atom for R _b0 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. R _b0 is preferably a hydrogen atom.
A ′ represents a single bond or a divalent linking group. The divalent linking group represents an ether group, an ester group, a carbonyl group, an alkylene group, or a divalent group obtained by combining these.
B ₂ represents a group represented by any one of the general formulas (V-1) to (V-4). In A ′, examples of the combined divalent group include those represented by the following formulae.
[0046]
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[0047]
In the above formula, R _ab and R _bb represent a hydrogen atom, an alkyl group, a substituted alkyl group, a halogen atom, a hydroxyl group, and 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 substituent of the substituted alkyl group include a hydroxyl group, a halogen atom, and an alkoxy group having 1 to 4 carbon atoms.
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. r1 represents an integer of 1 to 10, preferably an integer of 1 to 4. m represents an integer of 1 to 3, preferably 1 or 2.
[0048]
Although the specific example of the repeating unit represented by general formula (AI) is given to the following, the content of this invention is not limited to these.
[0049]
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[0050]
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[0051]
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[0052]
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[0053]
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[0054]
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[0055]
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[0056]
Moreover, the acid-decomposable resin of the present invention can further contain a repeating unit represented by the following general formula (VI).
[0057]
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[0058]
In the general formula (VI), A ₆ represents a single bond or a divalent linking group. The divalent linking group represents a single group or a combination of two or more groups selected from the group consisting of an alkylene group, a cycloalkylene group, an ether group, a thioether group, a carbonyl group, and an ester group.
R _6a represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a cyano group, or a halogen atom.
[0059]
In the general formula (VI), examples of the alkylene group represented by A ₆ include groups represented by the following formulae.
-[C (Rnf) (Rng)] r-
In the above formula, Rnf and Rng represent a hydrogen atom, an alkyl group, a substituted alkyl group, a halogen atom, a hydroxyl group, and 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 substituent of the substituted alkyl group include a hydroxyl group, a halogen atom, and an alkoxy 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 is an integer of 1-10.
In the general formula (VI), examples of the cycloalkylene group represented by A ₆ include those having 3 to 10 carbon atoms, such as a cyclopentylene group, a cyclohexylene group, and a cyclooctylene group.
[0060]
The bridged alicyclic ring containing Z ₆ may have a substituent. Examples of the substituent include a halogen atom, an alkoxy group (preferably having 1 to 4 carbon atoms), an alkoxycarbonyl group (preferably having 1 to 5 carbon atoms), an acyl group (for example, a formyl group and a benzoyl group), an acyloxy group ( For example, propyl carbonyloxy group, benzoyloxy group), an alkyl group (preferably having from 1 to 4 carbon atoms), a carboxyl group, a hydroxyl group and an alkylsulfonylsulfamoyl group (-CONHSO ₂ CH _3, etc.). In addition, the alkyl group as a substituent may be further substituted with a hydroxyl group, a halogen atom, an alkoxy group (preferably having 1 to 4 carbon atoms), or the like.
[0061]
In the general formula (VI), the oxygen atom of the ester group bonded to A ₆ may be bonded at any position of the carbon atom constituting the bridged alicyclic ring structure containing Z ₆ .
[0062]
Although the specific example of the repeating unit represented by general formula (VI) below is given, it is not limited to these.
[0063]
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[0064]
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[0065]
The acid-decomposable resin (A) of the present invention can further contain a repeating unit having a lactone structure represented by the following general formula (IV).
[0066]
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[0067]
In general formula (IV), R1a represents a hydrogen atom or a methyl group.
W ₁ represents a single bond or a divalent linking group. The divalent linking group represents a single group or a combination of two or more groups selected from the group consisting of an alkylene group, an ether group, a thioether group, a carbonyl group, and an ester group.
Ra ₁ , Rb ₁ , Rc ₁ , Rd ₁ and Re ₁ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. m and n each independently represents an integer of 0 to 3, and m + n is 2 or more and 6 or less.
[0068]
Examples of the alkyl group having 1 to 4 carbon atoms of Ra _{1 to} Re ₁ include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a t-butyl group. Can do.
[0069]
In the general formula (IV), examples of the alkylene group for W ₁ include groups represented by the following formulae.
− [C (Rf) (Rg)] r ₁ −
In the above formula, Rf and Rg represent a hydrogen atom, an alkyl group, a substituted 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 substituent of the substituted alkyl group include a hydroxyl group, a halogen atom, and an alkoxy 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 ₁ is an integer of 1 to 10.
[0070]
Examples of further substituents in the alkyl group include a carboxyl group, an acyloxy group, a cyano group, an alkyl group, a substituted alkyl group, a halogen atom, a hydroxyl group, an alkoxy group, a substituted alkoxy group, an acetylamide group, an alkoxycarbonyl group, and an acyl group. Can be mentioned.
Examples of the alkyl group include lower alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a cyclopropyl group, a cyclobutyl group, and a cyclopentyl group. Examples of the substituent of the substituted alkyl group include a hydroxyl group, a halogen atom, and an alkoxy group. Examples of the substituent of the substituted alkoxy group include an alkoxy 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 acyloxy group include an acetoxy group. Examples of the halogen atom include a chlorine atom, a bromine atom, a fluorine atom, and an iodine atom.
[0071]
Specific examples of the monomer corresponding to the repeating unit represented by the general formula (IV) are shown below, but are not limited thereto.
[0072]
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[0073]
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[0074]
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[0075]
In the specific example of the general formula (IV), (IV-17) to (IV-36) are preferable because the exposure margin becomes better.
Further, as the structure of the general formula (IV), those having an acrylate structure are preferable from the viewpoint that the edge roughness becomes good.
[0076]
The acid-decomposable resin (A) of the present invention may further contain a repeating unit having a group represented by the following general formula (VII).
[0077]
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[0078]
In general formula (VII), R _3c represents a hydroxyl group, and R _2c and R _4c each independently represents a hydrogen atom or an alkyl group. As an alkyl group, C1-C4 is preferable.
[0079]
Examples of the repeating unit having a group represented by the general formula (VII) include a repeating unit represented by the following general formula (AII).
[0080]
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[0081]
In general formula (AII), R _1c represents a hydrogen atom or a methyl group.
R _3c represents a hydroxyl group, and R _2c and R _4c each independently represent a hydrogen atom or an alkyl group. As an alkyl group, C1-C4 is preferable.
[0082]
Although the specific example of the repeating unit which has a structure represented by general formula (AII) below is given, it is not limited to these.
[0083]
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[0084]
In addition to the above repeating units, the acid-decomposable resin as component (A) includes dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and general required properties of resist, resolving power and heat resistance. Various repeating units can be contained for the purpose of adjusting sensitivity and the like.
[0085]
Examples of such a repeating unit include, but are not limited to, repeating structural units corresponding to the following monomers.
Thereby, the performance required for the acid-decomposable resin, in particular,
(1) Solubility in coating solvent,
(2) Film formability (glass transition point),
(3) Alkali developability,
(4) Membrane slip (hydrophobic, alkali-soluble group selection),
(5) Adhesion of unexposed part to substrate,
(6) Dry etching resistance,
Etc. can be finely adjusted.
As such a monomer, for example, a compound having one addition polymerizable unsaturated bond selected from acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, etc. Etc.
[0086]
Specifically, the following monomers can be mentioned.
Acrylic acid esters (preferably alkyl acrylates having an alkyl group with 1 to 10 carbon atoms):
Methyl acrylate, ethyl acrylate, propyl acrylate, amyl acrylate, cyclohexyl acrylate, ethyl hexyl acrylate, octyl acrylate, tert-octyl acrylate, chloroethyl acrylate, 2-hydroxyethyl acrylate 2,2-dimethylhydroxy Propyl acrylate, 5-hydroxypentyl acrylate, trimethylolpropane monoacrylate, pentaerythritol monoacrylate, benzyl acrylate, methoxybenzyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, and the like.
[0087]
Methacrylic acid esters (preferably alkyl methacrylate having 1 to 10 carbon atoms in the alkyl group):
Methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, chlorobenzyl methacrylate, octyl methacrylate, 2-hydroxyethyl methacrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl methacrylate, 2 , 2-dimethyl-3-hydroxypropyl methacrylate, trimethylolpropane monomethacrylate, pentaerythritol monomethacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate and the like.
[0088]
Acrylamides:
Acrylamide, N-alkylacrylamide (alkyl group 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-hydroxy Ethyl-N-methylacrylamide, N-2-acetamidoethyl-N-acetylacrylamide and the like.
[0089]
Methacrylamide:
Methacrylamide, N-alkylmethacrylamide (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 group, propyl group, butyl group), N-hydroxyethyl-N-methylmethacrylamide and the like.
[0090]
Allyl compounds:
Allyl esters (for example, allyl acetate, allyl caproate, allyl caprylate, allyl laurate, allyl palmitate, allyl stearate, allyl benzoate, allyl acetoacetate, allyl lactate, etc.), allyloxyethanol and the like.
[0091]
Vinyl ethers:
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 and the like.
[0092]
Vinyl esters:
Vinyl butyrate, vinyl isobutyrate, vinyl trimethyl acetate, vinyl diethyl acetate, vinyl valerate, vinyl caproate, vinyl chloroacetate, vinyl dichloroacetate, vinyl methoxyacetate, vinyl butoxyacetate, vinyl acetoacetate, vinyl lactate, vinyl -Β-phenylbutyrate, vinylcyclohexylcarboxylate and the like.
[0093]
Dialkyl itaconates:
Dimethyl itaconate, diethyl itaconate, dibutyl itaconate, etc.
Dialkyl esters or monoalkyl esters of fumaric acid; dibutyl fumarate and the like.
[0094]
Others include crotonic acid, itaconic acid, maleic anhydride, maleimide, acrylonitrile, methacrylonitrile, maleilonitrile and the like.
[0095]
In addition, any addition-polymerizable unsaturated compound that can be copolymerized with monomers corresponding to the above various repeating units may be copolymerized.
[0096]
In acid-decomposable resins, the molar ratio of each repeating unit is the resist dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and general resist performance required for resolution, heat resistance, sensitivity, etc. It is set appropriately to adjust.
[0097]
In the acid-decomposable resin, the content of the alicyclic lactone repeating unit A3 is preferably 5 to 65 mol%, more preferably 10 to 60 mol%, still more preferably 15 to 55 mol% in all repeating units.
In the acid-decomposable resin, the content of the repeating unit A1 (repeating unit represented by the general formula (I)) is preferably from 5 to 30 mol%, more preferably from 10 to 28 mol%, further preferably from all repeating units. Is 15 to 25 mol%.
In the acid-decomposable resin, the content of the repeating unit A2 (repeating unit having a partial structure containing an alicyclic hydrocarbon represented by general formulas (pI) to (pVI)) is 24 to 55 mol in all repeating units. % Is preferable, more preferably 26 to 50 mol%, still more preferably 28 to 45 mol%.
[0098]
Further, the content of the repeating unit based on the monomer of the further copolymer component in the resin can be appropriately set according to the performance of the desired resist. Generally, the general formula (V- 1) to a repeating unit having a partial structure containing a repeating unit having a group represented by any one of (V-4) and an alicyclic hydrocarbon represented by the above general formulas (pI) to (pVI); 99 mol% or less is preferable with respect to the total number of moles of the repeating units represented by the general formula (I), more preferably 90 mol% or less, and still more preferably 80 mol% or less.
[0099]
The acid-decomposable resin used in the present invention can be synthesized according to a conventional method (for example, radical polymerization). For example, as a general synthesis method, monomer species are charged into a reaction vessel in a batch or in the course of reaction, and if necessary, a reaction solvent such as ethers such as tetrahydrofuran, 1,4-dioxane, diisopropyl ether, methyl ethyl ketone, A ketone such as methyl isobutyl ketone, an ester solvent such as ethyl acetate, and the composition of the present invention such as propylene glycol monomethyl ether acetate described below are dissolved in a solvent that dissolves uniformly and then nitrogen, argon, etc. Polymerization is started using a commercially available radical initiator (azo initiator, peroxide, etc.) as necessary under an inert gas atmosphere. If desired, an initiator is added or added in portions, and after completion of the reaction, it is put into a solvent and a desired polymer is recovered by a method such as powder or solid recovery. The concentration of the reaction is 20% by weight or more, preferably 30% by weight or more, more preferably 40% by weight or more. The reaction temperature is 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 50-100 ° C.
[0100]
The weight average molecular weight of the resin according to the present invention is preferably 1,000 to 200,000 as a polystyrene conversion value by the GPC method. When the weight average molecular weight is less than 1,000, the heat resistance and dry etching resistance are deteriorated, which is not preferable. When the weight average molecular weight exceeds 200,000, the developability is deteriorated and the film forming property is deteriorated because the viscosity is extremely high. Produces less favorable results.
[0101]
Further, the dispersity (Mw / Mn) of the resin according to the present invention is preferably in the range of 1.4 to 3.5, more preferably in the range of 1.5 to 3.3, and 1.7 to 2.8. Is particularly preferred.
[0102]
In the positive resist composition of the present invention, the blending amount of all the resins according to the present invention in the entire composition is preferably 40 to 99.99% by weight, more preferably 50 to 99.97, based on the total resist solid content. % By weight.
[0103]
[2] (B) Compound that generates acid upon irradiation with actinic ray or radiation (photoacid generator)
The photoacid generator used in the present invention is a compound that generates an acid upon irradiation with actinic rays or radiation.
[0104]
As the photoacid generator used in the present invention, it is used as a photoinitiator for photocationic polymerization, a photoinitiator for radical photopolymerization, a photodecolorant for dyes, a photochromic agent, a microresist, or the like. Acid by known light (400-200 nm ultraviolet light, far ultraviolet light, particularly preferably g-line, h-line, i-line, KrF excimer laser beam), ArF excimer laser beam, electron beam, X-ray, molecular beam or ion beam Can be selected and used as appropriate.
[0105]
Examples of other photoacid generators used in the present invention include diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, onium salts such as arsonium salts, organic halogen compounds, organic metals / organics. Examples include halides, photoacid generators having an o-nitrobenzyl-type protecting group, compounds that generate photosulfonic acid by photolysis, such as iminosulfonates, disulfone compounds, diazoketosulfones, diazodisulfone compounds, etc. Can do.
Moreover, the group which generate | occur | produced the acid by these light, or the compound which introduce | transduced the compound into the principal chain or side chain of the polymer can be used.
[0106]
Furthermore, VNRPillai, Synthesis, (1), 1 (1980), A. Abad etal, Tetrahedron Lett., (47) 4555 (1971), DHR Barton etal, J. Chem. Soc., (C), 329 (1970), Compounds that generate an acid by light as described in US Pat. No. 3,779,778, European Patent 126,712 and the like can also be used.
[0107]
Among the compounds that decompose upon irradiation with actinic rays or radiation to generate an acid, other photoacid generators that are particularly effectively used in combination will be described below. (1) An oxazole derivative represented by the following general formula (PAG1) substituted with a trihalomethyl group or an S-triazine derivative represented by the general formula (PAG2).
[0108]
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[0109]
In the formula, R ²⁰¹ represents a substituted or unsubstituted aryl group or alkenyl group, R ₂₀₂ represents a substituted or unsubstituted aryl group, alkenyl group, alkyl group, or —C (Y) ₃ . Y represents a chlorine atom or a bromine atom.
Specific examples include the following compounds, but are not limited thereto.
[0110]
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[0111]
(2) An iodonium salt represented by the following general formula (PAG3) or a sulfonium salt represented by the general formula (PAG4).
[0112]
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[0113]
Here, the formulas Ar ¹ and Ar ² each independently represent a substituted or unsubstituted aryl group. R ²⁰³ , R ²⁰⁴ and R ²⁰⁵ each independently represents a substituted or unsubstituted alkyl group or aryl group.
[0114]
Z − represents a counter anion, for example, perfluoroalkanesulfonic acid anion such as BF ₄ ⁻ , AsF ₆ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , SiF ₆ ²⁻ , ClO ₄ ⁻ , CF ₃ SO ₃ ⁻ , penta Examples include, but are not limited to, condensed polynuclear aromatic sulfonate anions such as fluorobenzene sulfonate anion and naphthalene-1-sulfonate anion, anthraquinone sulfonate anion, and sulfonate group-containing dyes.
[0115]
Two of R ²⁰³ , R ²⁰⁴ and R ²⁰⁵ and Ar ¹ and Ar ² may be bonded via a single bond or a substituent.
[0116]
Specific examples include the following compounds, but are not limited thereto.
[0117]
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[0118]
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[0119]
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[0120]
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[0121]
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[0122]
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[0123]
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[0124]
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[0125]
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[0126]
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[0127]
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[0128]
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[0129]
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[0130]
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[0131]
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[0132]
In the above, Ph represents a phenyl group.
The above onium salts represented by the general formulas (PAG3) and (PAG4) are known and can be synthesized, for example, by the methods described in U.S. Pat. Nos. 2,807,648 and 4,247,473, JP-A-53-101,331, etc. .
[0133]
(3) A disulfone derivative represented by the following general formula (PAG5) or an iminosulfonate derivative represented by the general formula (PAG6).
[0134]
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[0135]
In the formula, Ar ³ and Ar ⁴ each independently represent a substituted or unsubstituted aryl group. R ²⁰⁶ represents a substituted or unsubstituted alkyl group or aryl group. A represents a substituted or unsubstituted alkylene group, alkenylene group, or arylene group.
[0136]
Specific examples include the following compounds, but are not limited thereto.
[0137]
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[0138]
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[0139]
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[0140]
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[0141]
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[0142]
(4) A diazodisulfone derivative represented by the following general formula (PAG7).
[0143]
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[0144]
Here, R represents a linear, branched or cyclic alkyl group, or an aryl group which may be substituted.
Specific examples include the following compounds, but are not limited thereto.
[0145]
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[0146]
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[0147]
The amount of these photoacid generators added is usually in the range of 0.01 to 30% by weight, preferably 0.3 to 20% by weight, more preferably 0.8%, based on the solid content in the composition. It is used in the range of 5 to 10% by weight.
If the addition amount of the photoacid generator is less than 0.001% by weight, the sensitivity tends to be low, and if the addition amount is more than 30% by weight, the light absorption of the resist becomes too high, resulting in deterioration of the profile or process. There is a tendency that the margin (especially baking) becomes narrow.
[0148]
[3] Other additives In the positive resist composition of the present invention, an acid-decomposable dissolution inhibiting compound, a dye, a plasticizer, a surfactant, a photosensitizer, an organic basic compound, and A compound or the like that promotes solubility in a developer can be contained.
[0149]
The positive resist composition of the present invention preferably contains (C) a fluorine-based and / or silicon-based surfactant.
The positive resist composition of the present invention preferably contains either a fluorine-based surfactant, a silicon-based surfactant, and a surfactant containing both fluorine atoms and silicon atoms, or two or more thereof. .
When the positive resist composition of the present invention contains the acid-decomposable resin and the surfactant, it is particularly effective when the pattern line width is narrower, and development defects are further improved.
As these surfactants, for example, JP-A-62-36663, JP-A-61-226746, JP-A-61-226745, JP-A-62-170950, JP-A-63-34540, JP-A-63-34540 7-230165, JP-A-8-62834, JP-A-9-54432, JP-A-9-5988, U.S. Patents 5405720, 5360692, 5529881, 5296330, 5436098, 5576143 No. 5945511 and No. 5842451, and the following commercially available surfactants can be used as they are. Commercially available surfactants that can be used include, for example, F-top EF301, EF303 (made by Shin-Akita Kasei Co., Ltd.), Florard FC430, 431 (made by Sumitomo 3M Ltd.), MegaFuck F171, F173, F176, F189, R08 (Dainippon Ink Co., Ltd.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (Asahi Glass Co., Ltd.), Troisol S-366 (Troy Chemical Co., Ltd.) and other fluorine-based interfaces An activator or a silicon-based surfactant can be mentioned. Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used as a silicon surfactant.
[0150]
The compounding amount of the surfactant is usually 0.001% to 2% by weight, preferably 0.01% to 1% by weight, based on the solid content in the composition of the present invention. These surfactants may be added alone or in some combination.
[0151]
As surfactants that can be used in addition to the above, specifically, polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene oleyl ether, etc. , 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.
[0152]
A preferable organic basic compound (D) that can be used in the present invention is a compound that is more basic than phenol. Of these, nitrogen-containing basic compounds are preferable, and specific examples include compounds having the following structures.
[0153]
Embedded image
[0154]
Here, R ²⁵⁰ , R ²⁵¹ and R ²⁵² are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aminoalkyl group having 1 to 6 carbon atoms, a hydroxyalkyl group having 1 to 6 carbon atoms, or carbon. A substituted or unsubstituted aryl group of formula 6 to 20, wherein R ²⁵¹ and R ²⁵² may be bonded to each other to form a ring.
[0155]
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[0156]
(In the formula, R ²⁵³ , R ²⁵⁴ , R ²⁵⁵ and R ²⁵⁶ each independently represents an alkyl group having 1 to 6 carbon atoms.)
Further preferred compounds are nitrogen-containing basic compounds having two or more nitrogen atoms of different chemical environments in one molecule, and particularly preferably both a substituted or unsubstituted amino group and a ring structure containing a nitrogen atom. Or a compound having an alkylamino group. Preferred examples include substituted or unsubstituted guanidine, substituted or unsubstituted aminopyridine, substituted or unsubstituted aminoalkylpyridine, substituted or unsubstituted aminopyrrolidine, substituted or unsubstituted indazole, substituted or unsubstituted Pyrazole, substituted or unsubstituted pyrazine, substituted or unsubstituted pyrimidine, substituted or unsubstituted purine, substituted or unsubstituted imidazoline, substituted or unsubstituted pyrazoline, substituted or unsubstituted piperazine, substituted or unsubstituted amino Examples include morpholine and substituted or unsubstituted aminoalkylmorpholine. Preferred substituents are amino group, aminoalkyl group, alkylamino group, aminoaryl group, arylamino group, alkyl group, alkoxy group, acyl group, acyloxy group, aryl group, aryloxy group, nitro group, hydroxyl group, cyano group It is.
[0157]
Preferable specific examples of the nitrogen-containing basic compound 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- Minopiperidine, 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-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, 1,4-diazabicyclo [2.2.2] octane, 2,4,5- Triphenylimidazole, N-methylmorpholine, N-ethylmorpholine, N-hydroxyethylmorpholine, N-benzylmorpholine, cyclohex Examples include tertiary morpholine derivatives such as lumorpholinoethylthiourea (CHMETU), and hindered amines described in JP-A No. 11-52575 (for example, those described in the publication [0005]), but are not limited thereto. Absent.
[0158]
Particularly preferred examples are 1,5-diazabicyclo [4.3.0] non-5-ene, 1,8-diazabicyclo [5.4.0] undec-7-ene, 1,4-diazabicyclo [2. 2.2] Octane, 4-dimethylaminopyridine, hexamethylenetetramine, 4,4-dimethylimidazoline, pyrroles, pyrazoles, imidazoles, pyridazines, pyrimidines, tertiary morpholines such as CHMETU, bis (1, And hindered amines such as 2,2,6,6-pentamethyl-4-piperidyl) sebagate.
Among them, 1,5-diazabicyclo [4.3.0] non-5-ene, 1,8-diazabicyclo [5.4.0] undec-7-ene, 1,4-diazabicyclo [2.2.2] Octane, 4-dimethylaminopyridine, hexamethylenetetramine, CHMETU, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebagate are preferred.
[0159]
These nitrogen-containing basic compounds are used alone or in combination of two or more. The usage-amount of a nitrogen-containing basic compound is 0.001-10 weight% normally with respect to solid content of the whole composition of the photosensitive resin composition, Preferably it is 0.01-5 weight%. If it is less than 0.001% by weight, the effect of adding the nitrogen-containing basic compound cannot be obtained. On the other hand, when it exceeds 10% by weight, there is a tendency for the sensitivity to deteriorate and the developability of the non-exposed area to deteriorate.
[0160]
The positive resist 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 monomethyl ether acetate (PGMEA), toluene, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, methyl methoxypropionate, ethyl ethoxypropionate, methyl pyruvate, ethyl pyruvate, propyl pyruvate N, N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, tetrahydrofuran, etc. Preferred, to use these solvents singly or in combination.
[0161]
Among these, preferable solvents include propylene glycol monomethyl ether acetate, 2-heptanone, γ-butyrolactone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether Butyl acetate, methyl lactate, ethyl lactate, methyl methoxypropionate, ethyl ethoxypropionate, N-methylpyrrolidone and tetrahydrofuran.
[0162]
Such a positive resist composition of the present invention is applied onto a substrate to form a thin film. The film thickness of this coating film is preferably 0.2 to 1.2 μm.
Examples of the inorganic substrate that can be used in the present invention include a normal BareSi substrate, an SOG substrate, and a substrate having an inorganic antireflection film described below. In the present invention, a commercially available inorganic or organic antireflection film can be used as necessary.
[0163]
As the antireflection film, an inorganic film type such as titanium, titanium dioxide, titanium nitride, chromium oxide, carbon, α-silicon, and an organic film type made of a light absorber and a polymer material can be used. The former requires equipment such as a vacuum deposition apparatus, a CVD apparatus, and a sputtering apparatus for film formation. Examples of the organic antireflection film include a condensate of a diphenylamine derivative and a formaldehyde-modified melamine resin described in JP-B-7-69611, an alkali-soluble resin, a light absorber, and maleic anhydride copolymer described in US Pat. No. 5,294,680. A reaction product of a coalescence and a diamine type light absorbing agent, a resin binder described in JP-A-6-186863 and a methylolmelamine thermal crosslinking agent, a carboxylic acid group, an epoxy group and a light-absorbing group described in JP-A-6-118656. An acrylic resin type antireflection film in the same molecule, a composition comprising methylol melamine and a benzophenone light absorber described in JP-A-8-87115, and a low molecular light absorber added to a polyvinyl alcohol resin described in JP-A-8-179509 And the like. Further, as the organic antireflection film, DUV30 series, DUV-40 series, ARC25, AC-2, AC-3, AR19, AR20, etc., manufactured by Brewer Science can be used.
[0164]
Appropriate use of the resist solution on a substrate (eg, silicon / silicon dioxide coating) used for the manufacture of precision integrated circuit elements (on a substrate provided with the antireflection film if necessary), spinner, coater, etc. A good resist pattern can be obtained by applying through a predetermined coating method, exposing through a predetermined mask, baking and developing. Here, the exposure light is preferably light having a wavelength of 150 nm to 250 nm. Specific examples include KrF excimer laser (248 nm), ArF excimer laser (193 nm), F2 excimer laser (157 nm), X-rays, electron beam, and the like.
[0165]
Examples of the developer 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, diethylamine, and di-n. -Secondary amines such as butylamine; tertiary amines such as triethylamine and methyldiethylamine; alcohol amines such as dimethylethanolamine and triethanolamine; quaternary ammonium salts such as tetramethylammonium hydroxide and tetraethylammonium hydroxide. An alkaline aqueous solution of cyclic amines such as pyrrole and pihelidine can be used.
Furthermore, an appropriate amount of alcohol or surfactant may be added to the alkaline aqueous solution.
[0166]
【Example】
EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples.
[0167]
Synthesis Example (1) Synthesis of Resin (1-1) 2-Adamantyl-2-propyl methacrylate (repeating unit A2), norbornane lactone acrylate, dihydroxyadamantane methacrylate (repeating unit A1) were charged at a ratio of 50/40/10, It melt | dissolved in methyl ethyl ketone / tetrahydrofuran = 9/1, and 450 g of solutions with a solid content concentration of 22% were prepared. To this solution, 10 mol% of V-601 manufactured by Wako Pure Chemical Industries, Ltd. was added and added dropwise to 40 g of methyl ethyl ketone heated to 65 ° C. over 6 hours in a nitrogen atmosphere. The reaction liquid was stirred for 4 hours after completion | finish of dripping. After completion of the reaction, the reaction solution was cooled to room temperature, crystallized in 5 L of a mixed solvent of methanol / ISO propyl alcohol = 3/1, and the precipitated white powder was collected, and the obtained powder was reslurried with 1 L of methanol. The target resin (1-1) was recovered.
The polymer composition ratio determined from NMR was 46/42/12 (A1 / A2 = 0.26, A1 + A2 = 58 mol%). Moreover, the weight average molecular weight of standard polystyrene conversion calculated | required by GPC measurement was 13100, and dispersion degree Mw / Mn = 2.2.
[0168]
Synthesis Example (2) Synthesis of Resin (1-2) 2-Adamantyl-2-propyl methacrylate, norbornane lactone acrylate and dihydroxyadamantane methacrylate were charged at a ratio of 50/40/10 and dissolved in methyl ethyl ketone / tetrahydrofuran = 9/1. 450 g of a solution having a solid content concentration of 22% was prepared. To this solution, 10 mol% of V-601 manufactured by Wako Pure Chemical Industries, Ltd. was added and added dropwise to 40 g of methyl ethyl ketone heated to 65 ° C. over 6 hours in a nitrogen atmosphere. The reaction liquid was stirred for 4 hours after completion | finish of dripping. After completion of the reaction, the reaction solution is cooled to room temperature, crystallized in 5 L of hexane solvent, and the precipitated white powder is collected, then again dissolved in tetrahydrofuran, and reprecipitated in 5 L of hexane, which is the target product. Resin (1-2) was recovered.
The polymer composition ratio determined from NMR was 46/42/12 (A1 / A2 = 0.26, A1 + A2 = 58 mol%). Moreover, the weight average molecular weight of standard polystyrene conversion calculated | required by GPC measurement was 10200, and dispersion degree Mw / Mn = 3.5.
[0169]
Synthesis Example (3) Synthesis of Resin (1-3) 2-Adamantyl-2-propyl methacrylate, norbornane lactone acrylate and dihydroxyadamantane methacrylate were charged at a ratio of 50/40/10 and dissolved in methyl ethyl ketone / tetrahydrofuran = 9/1. 450 g of a solution having a solid content concentration of 22% was prepared. To this solution, 10 mol% of V-601 manufactured by Wako Pure Chemical Industries, Ltd. was added and added dropwise to 40 g of methyl ethyl ketone heated to 65 ° C. over 6 hours in a nitrogen atmosphere. The reaction liquid was stirred for 4 hours after completion | finish of dripping. After completion of the reaction, the reaction solution was cooled to room temperature, crystallized in 5 L of a mixed solvent of hexane / ethyl acetate = 85/15, and the precipitated white powder was collected, and then again dissolved in tetrahydrofuran. It was reprecipitated in 5 L of a mixed solvent of ethyl acetate = 85/15 to recover the target resin (1-3).
The polymer composition ratio determined from NMR was 45/43/12 (A1 / A2 = 0.27, A1 + A2 = 57 mol%). Moreover, the weight average molecular weight of standard polystyrene conversion calculated | required by GPC measurement was 11300, and dispersion degree Mw / Mn = 2.9.
[0170]
Synthesis Example (4) Synthesis of Resin (1-4) Resin (1-1) obtained in Synthesis Example (1) was subjected to column separation by silica gel column chromatography with hexane / acetone mixed solvent (99/1 to 50/50). I made a picture.
The polymer composition ratio determined from NMR was 45/43/12 (A1 / A2 = 0.27, A1 + A2 = 57 mol%). Moreover, the weight average molecular weight of standard polystyrene conversion calculated | required by GPC measurement was 11700, and dispersion degree Mw / Mn = 1.4.
[0171]
Resins (2) to (12) having the composition ratios and molecular weights shown in the table below were synthesized in the same manner as in the above synthesis example. (Each repeating unit in the table is shown in order from the left of the displayed structural formula.)
[0172]
[Table 1]
[0173]
[Table 2]
[0174]
Moreover, the structure of said resin (1)-(12) is shown below.
[0175]
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[0176]
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[0177]
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[0178]
Examples 1-27 and Comparative Examples 1-2
(Preparation and evaluation of positive resist composition)
2 g of each of the resins shown in Table 2 synthesized in the above synthesis example,
A photoacid generator (each amount is shown in the table), 4 mg of an organic basic compound (amine) and, if necessary, a surfactant (10 mg) are added as shown in Table 2, and the ratio of the solid content is 14% by weight. Were dissolved in a 70/30 mixed solvent of PGMEA / ethyl lactate and then filtered through a 0.1 μm microfilter to prepare positive resist compositions of Examples 1-27 and Comparative Examples 1-2.
[0179]
In addition, as resin of Comparative Examples 1-2, resin (20) described in JP-A-2001-109154 was used. In addition, the mixing ratio of the mixture is shown in parentheses in the basic compound column in the table.
[0180]
[Table 3]
[0181]
As surfactant,
W1: Mega Fuck F176 (Dainippon Ink Co., Ltd.) (Fluorine)
W2: Megafuck R08 (Dainippon Ink Co., Ltd.) (fluorine and silicone)
W3: Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.)
W4: Polyoxyethylene nonylphenyl ether W5: Troisol S-366 (manufactured by Troy Chemical Co., Ltd.)
Represents.
[0182]
As an amine,
1 represents 1,5-diazabicyclo [4.3.0] -5-nonene (DBN);
2 represents bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebagate 3, trioctylamine 4, triphenylimidazole 5, antipyrine 6 represents 2,6-diisopropylaniline.
[0183]
(Evaluation test)
First, DUV30J manufactured by Brewer Science Co., Ltd. was applied to a silicon wafer at 160 nm using a spin coater and dried, and then the positive resist composition solution obtained thereon was applied thereon, dried at 130 ° C. for 90 seconds, and about 0 A positive photoresist film having a thickness of 4 μm was prepared and exposed to an ArF excimer laser (ArF stepper manufactured by Ultratech Co., Ltd. having a wavelength of 193 nm and NA = 0.6). The heat treatment after exposure was performed at 120 ° C. for 90 seconds, developed with a 2.38% tetramethylammonium hydroxide aqueous solution, and rinsed with distilled water to obtain a resist pattern profile.
The resist pattern of the silicon wafer thus obtained was observed with a scanning microscope (SEM), and the resist was evaluated as follows.
[0184]
[Pattern collapse] Pattern collapse occurs when the focus is further changed by ± 0.4 μm on the overexposure side with respect to the exposure amount E1 for reproducing the mask pattern of 0.13 μm (L / S = 1/1). The pattern collapse was observed with an SEM, the exposure amount at which the pattern collapse occurred was E2, and (E2-E1) × 100 / E1 (%) was used as an index of the pattern collapse. A large value is good in preventing pattern collapse, and a small value is inferior.
[0185]
[Surface roughening during etching]
Etching a 0.15 μm contact hole pattern with CHF ₃ / O ₂ = 8/2 plasma or CHF ₃ / O ₂ = 13/6 plasma for 60 seconds, and observing the cross section and surface of the obtained sample with an SEM. , X that produces pinhole-like defects (the lower layer of the non-processed portion is etched), surface roughness occurred but no defects occurred, but those that had hole deformation △, surface roughness Good ones that are small and have no deformation of the holes are marked with ◯.
These evaluation results are shown in Table 3.
[0186]
[Line edge roughness]
The distance from the reference line where the edge should be in the range of the edge of 5 μm in the longitudinal direction of the 130 nm line pattern obtained by the minimum exposure amount reproducing the 130 nm (line / space = 1/1) line pattern in the mask ( 50 points were measured with Hitachi, Ltd. S-9220, the standard deviation was obtained, and 3σ was calculated. A smaller value indicates better performance.
[0187]
[Density dependency]
The line width variation rate of an isolated line pattern of 150 nm at an exposure amount for reproducing a mask pattern of 130 nm (pitch 1/1) was measured.
These evaluation results are shown in Table 3.
[0188]
[Table 4]
[0189]
As is apparent from the results in Table 3, it can be seen that the positive resist composition of the present invention is excellent in terms of prevention of pattern collapse and surface roughening during etching, edge roughness and density dependency.
[0190]
【The invention's effect】
The positive resist composition of the present invention is excellent in prevention of pattern collapse, prevention of surface roughness during etching, and line edge roughness and density dependency. Therefore, it is suitably used for lithography using far ultraviolet rays such as ArF excimer laser exposure. In particular, when the acid-decomposable resin A contains a repeating unit A1 having a dihydroxy or trihydroxyadamantyl group, a repeating unit A2 having an acid-decomposable alicyclic group, and an alicyclic lactone repeating unit A3, a remarkable effect is obtained. .

Claims (5)

(A) At least a repeating unit A1 having a dihydroxyadamantyl group or a trihydroxyadamantyl group, a repeating unit A2 having an acid-decomposable alicyclic group , and any of the following general formulas (V-1) to (V-4) Containing a repeating unit A3 having a group represented as a constituent unit, containing a resin whose rate of dissolution in an alkaline developer is increased by the action of an acid, and (B) a compound capable of generating an acid upon irradiation with actinic rays or radiation. A positive resist composition, wherein the composition molar ratio A1 / A2 of the repeating unit A1 and the repeating unit A2 in the resin (A) is 0.15 or more and 1.0 or less, and in the resin (A) A positive resist composition, wherein the total content of the repeating unit A1 and the repeating unit A2 is 40 to 70 mol%.
In General Formulas (V-1) to (V-4), R _{1b to} R _5b each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, or an alkenyl group that may have a substituent. Two of R _{1b to} R _5b may combine to form a ring. The composition according to claim 1, wherein A1 / A2 is 0.35 or more and 1.0 or less. The composition according to claim 1 or 2, wherein the repeating unit A1 having a dihydroxyadamantyl group or a trihydroxyadamantyl group is a repeating unit represented by the following general formula (I).
In the general formula (I), R ₁ represents a hydrogen atom, an alkyl group, a halogen atom or a cyano group, and R ₂ represents a hydrogen atom or a hydroxyl group. The repeating unit A2 having an acid-decomposable alicyclic group is selected from the group of repeating units having a partial structure containing an alicyclic hydrocarbon represented by the following general formula (pI) to general formula (pVI). The composition in any one of -3.
(Wherein R ₁₁ represents a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group or a sec-butyl group, and Z represents an alicyclic hydrocarbon group together with a carbon atom. Represents the atomic group necessary to form.
R _{12 to} R ₁₆ each independently represents a linear or branched alkyl group or alicyclic hydrocarbon group having 1 to 4 carbon atoms, provided that at least one of R _{12 to} R ₁₄ , or Either R ₁₅ or R ₁₆ represents an alicyclic hydrocarbon group.
R _{17 to} R ₂₁ each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or an alicyclic hydrocarbon group, provided that at least one of R _{17 to} R ₂₁ Represents an alicyclic hydrocarbon group. Further, either R ₁₉ or R ₂₁ represents a linear or branched alkyl group or alicyclic hydrocarbon group having 1 to 4 carbon atoms.
R _{22 to} R ₂₅ each independently represents a linear or branched alkyl group having 1 to 4 carbon atoms or an alicyclic hydrocarbon group, provided that at least one of R _{22 to} R ₂₅ is a fat Represents a cyclic hydrocarbon group. R ₂₃ and R ₂₄ may be bonded to each other to form a ring. ) A resist film is formed with the composition according to claim 1,
A pattern forming method comprising exposing and developing the resist film.