JP2001142217A - Photosensitive base material, resist pattern forming method using same and positive resist composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost photosensitive base material particularly for KrF laser light or for light having a shorter wavelength than F2 laser light excellent in the shape of a resist pattern and dry etching resistance, having high resolution and excellent also in SEM resistance, a resist pattern forming method using the base material and a positive resist composition. SOLUTION: A resist layer is disposed on a substrate in 500-5,800 Å thickness to obtain the objective photosensitive base material. A composition for the resist layer contains (A) a compound which generates an acid when irradiated, (B) an alkali-soluble novolak resin and (C) a compound having at least one acid dissociable dissolution inhibiting group which is dissociated by the action of the acid generated from the component A to generate an organic carboxylic acid. The photosensitive base material is successively subjected to selective exposure with KrF excimer laser light or light having a shorter wavelength than or F2 laser light, post-exposure heating and alkali development to obtain the objective resist pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a photosensitive substrate, a method for forming a resist pattern using the same, and a positive resist composition.

[0002]

2. Description of the Related Art In recent years, the degree of integration of semiconductor devices has been further increased, and mass production of LSIs having a design rule of 0.20 μm has already begun.
Mass production of μm LSIs is about to begin. On the other hand, although a large number of proposals have been made so far for chemically amplified resists, today's chemically amplified positive resists are, as proposed in JP-B-2-27660, Kr.
A base resin in which a hydroxyl group of polyhydroxystyrene having high transparency to F laser light is replaced by an acid dissociable alkali dissolution inhibiting group such as a t-boc (tert-butoxycarbonyloxy) group and an acid generator as main components. The two-component resist is the basis. The outline of the principle of forming a resist pattern on a resist proposed in this publication is as follows. Since the base resin has a t-boc group, its alkali solubility is lower than that of polyhydroxystyrene having no t-boc group. Then, when such a resin is mixed with an acid generator and selectively exposed, the t-boc group is dissociated in the exposed portion by the action of the acid generated from the acid generator, polyhydroxystyrene is generated, and alkali-soluble. Become. At this time, the alkali solubility of the base resin is such that the t-boc group is dissociated by exposure and the alkali solubility inherent in polyhydroxystyrene is restored, and no further alkali solubility can be obtained.

On the other hand, (1) Japanese Patent Application Laid-Open No. 4-28704
No. 4, JP-A-5-40342, (3)
JP-A-5-313372, and (4) JP-A-6-313
In JP-A-130670, (α) novolak resin is used as a base resin component, and an acid dissociable, dissolution inhibiting group is dissociated by the action of a (β) acid generator and (γ) acid to generate an organic carboxylic acid. There has been proposed a three-component chemically amplified resist composition containing a compound capable of being substituted (a compound having a carboxyl group substituted with an acid dissociable, dissolution inhibiting group). Such three-component resists are described in detail in the gazettes (2) and (3) in particular. However, a carboxylic acid is generated from the (γ) component by the action of an acid generated by exposure, Due to the presence of the acid, alkali solubility higher than the inherent alkali solubility of the component (α) can be obtained. Therefore, there is an effect that the contrast between the exposed portion and the unexposed portion is excellent. However, due to the low transparency of the novolak resin with respect to the KrF laser, the resist pattern shape and resolution are insufficient for the conventional production of semiconductor devices requiring a resist pattern size of up to 0.20 μm. Could not be used. Also, the design rule 0.15μ
m and below, as a next-generation and next-generation resist material, F ₂ laser (157 nm) and E
There is an urgent need to develop a resist material for UV (vacuum ultraviolet 13 nm). Since light energy of such a resist material is increased by shortening the wavelength, it is necessary to improve dry etching resistance and SEM resistance. The SEM resistance means that the formed resist pattern needs to be observed with a scanning electron microscope (SEM), and the resist pattern formed at the time of observation with such a microscope uses the electron beam used for the microscope. It is a problem that it is affected and deteriorates. However, although some resist materials for short wavelength light below the F ₂ laser have been proposed, these problems have not been sufficiently solved. In addition, it has become more important in the semiconductor industry than ever before to provide an inexpensive resist due to a sharp drop in the price of a semiconductor device such as a 64 mega DRAM.

[0004]

Accordingly, in the present invention, KrF, which is inexpensive, has excellent resist pattern shape and dry etching resistance, and has high resolution,
It is an object of the present invention to provide a photosensitive substrate for laser, a method for forming a resist pattern using the same, and a positive resist composition. Another object of the present invention, the above problems, i.e. dry etching resistance and SEM resistance improved F ₂ laser following short wavelength photosensitive substrate for the resist pattern forming method and the positive using the same The present invention provides a resist composition.

[0005]

Means for Solving the Problems The present inventors have found that the contrast between an exposed portion and an unexposed portion, which is an advantage of the chemically amplified positive resist described in the prior arts (1) to (4) above, is improved. Focusing on the superiority and the fact that novolak resins are very inexpensive compared to polyhydroxystyrene, the above problem can be solved by adopting such a three-component resist in an extremely thin thin film resist process of 500 to 5800 °. As a result, the present invention has been completed. The prior arts (1) to (4) described above include:
There is no mention or suggestion of a very thin film resist process as in the present invention.

That is, the present invention is a photosensitive substrate having a resist layer provided on a substrate to a thickness of 500 to 5800 °, wherein the resist composition for forming the resist layer comprises (A)
A compound which generates an acid upon irradiation with radiation, (B) an alkali-soluble novolak resin, and (C) at least one acid-dissociable, dissolution-inhibiting group, which dissociates by the action of an acid generated from the component (A). A photosensitive resist composition comprising a compound capable of generating an organic carboxylic acid;
rF excimer laser or F ₂ selective exposure by laser following short-wavelength light, a method for forming a resist pattern, characterized by sequentially applying a post-exposure heating, and alkali development, and is intended to provide the resist composition.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The photosensitive substrate of the present invention comprises a resist layer 5 on a substrate.
It is provided with a thickness of 00 to 5800 °, and is characterized by providing such an extremely thin resist layer. Due to this feature, the exposure efficiency is maximized for the selective exposure with short wavelength light of KrF laser or F ₂ laser or less, and 0.40 μm using KrF light.
Significantly improved resist pattern shape and resolution in the manufacture of semiconductor devices that require resist pattern sizes of 0.2 m or less, especially 0.20 μm or less, and 0.15 μm or less using F ₂ laser or less. Is done. By using a more inexpensive novolak resin, it is possible to significantly reduce costs,
Even a thin resist layer having a thickness of up to 5800 ° has excellent dry etching resistance and can be suitably used for manufacturing semiconductor devices. The resist composition for forming the resist layer includes: (A) a compound which generates an acid upon irradiation with radiation;
(B) an alkali-soluble novolak resin and (C) a compound having at least one acid dissociable, dissolution inhibiting group and capable of generating an organic carboxylic acid by dissociation of the dissolution inhibiting group by the action of an acid generated from the component (A). The constituent material is not particularly limited as long as it is a positive resist composition containing it, but a positive resist composition suitable in the present invention will be described below.

[0008] The component (A) is a compound that generates an acid upon irradiation with radiation, a so-called acid generator. The acid generator is
Various types of onium salts such as iodonium salts and sulfonium salts, oxime sulfonates, bisalkyl or bisarylsulfonyldiazomethanes, nitrobenzyl sulfonates, iminosulfonates, disulfones and the like are known. Known acid generators can be used without particular limitation. In particular, in the present invention, in order to favorably dissociate the component (C) described below with an acid, an onium salt having a strong fluorinated alkyl sulfonate ion as an anion is preferable, since the generated acid has a high strength. As such an onium salt, the cation is substituted with a lower alkyl group such as a methyl group, an ethyl group, a propyl, an n-butyl group or a tert-butyl, or a lower alkoxy group such as a methoxy group or an ethoxy group. And diphenyliodonium or triphenylsulfonium which may be unsubstituted, di-lower alkylmonophenylsulfonium, lower alkylcyclohexyl 2-oxocyclohexylsulfonium and the like. The anion is a fluoroalkyl sulfonate ion in which some or all of the hydrogen atoms of the alkyl group are fluorinated. As the number of carbon atoms increases and the fluorination rate (the ratio of fluorine atoms in the alkyl group) decreases, the strength of the sulfonic acid decreases. Therefore, all of the hydrogen atoms of the alkyl group having 1 to 10 carbon atoms are fluorinated. Preferred are fluorinated alkyl sulfonic acids. Such onium salts are represented by the following general formulas (III), (IV) and (V)
And (VI).

[0009]

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[0010]

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[0011]

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[0012]

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(Wherein R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 2 carbon atoms, ¹⁰ is an alkyl group having 1 to 4 carbon atoms, and X ^- is a fluoroalkylsulfonate ion.) Specifically, trifluoromethanesulfonate or nonafluorobutanesulfonate of diphenyliodonium, bis (4-tert- Butylphenyl) iodonium trifluoromethanesulfonate or nonafluorobutanesulfonate, triphenylsulfonium trifluoromethanesulfonate or nonafluorobutanesulfonate, tri (4-methylphenyl) sulfonium trifluoromethanesulfonate or nonafluorobutanesulfonate, tri 4-methoxyphenyl) sulfonium trifluoromethanesulfonate or nonafluorobutanesulfonate; dimethylphenylsulfonium trifluoromethanesulfonate or nonafluorobutanesulfonate; methylcyclohexyl 2-oxocyclohexylsulfonium trifluoromethanesulfonate or nonafluorobutanesulfonate; . Of these, general formulas (III) and (IV)
And iodonium or sulfonium methanesulfonate or nonafluorobutanesulfonate are preferred. These may be used alone or in combination of two or more. The amount of component (A) is 0.5 to 20 parts by weight, preferably 5 to 15 parts by weight, per 100 parts by weight of component (B). Deviating from this range results in insufficient image formation,
Further, it is difficult to form a uniform resist solution.

The component (B) is an alkali-soluble novolak resin. As described in the prior art, by using such a novolak resin as the base resin component, the alkali dissolution of the novolak resin inherently possesses by the interaction with the carboxylic acid generated from the component (C) described below. The alkali solubility is further improved than the solubility, and thereby, the contrast between the exposed and unexposed portions is excellent, and high resolution is achieved by an extremely thin thin film resist process of 500 to 5800 °. Moreover, precisely because it is such a very thin film resist process, also it does not significantly interfere with the resolution low transparency of the novolak resin by a KrF excimer laser or F ₂ laser following short-wavelength light. Furthermore, due to the three-dimensional network structure of the novolak resin, it has better dry etching resistance and SEM resistance than polyhydroxystyrene, and is also suitable for a thin film resist process.

Such alkali-soluble novolak resins are those commonly used in non-chemically amplified positive resists containing a naphthoquinonediazidesulfonic acid ester and a novolak resin, and those described in the above-mentioned prior art. From these, it can be used without particular limitation. More specifically, a novolak resin obtained by condensing a phenol and an aldehyde in the presence of an acidic catalyst can be mentioned. Examples of phenols include cresols such as phenol, m-cresol, p-cresol, and o-cresol; 2,3-xylenol;
Xylenols such as -xylenol, 3,5-xylenol and 3,4-xylenol; and alkylphenols such as 2,3,5-trimethylphenol and 2,3,5-triethylphenol. One or more of these phenols may be used simultaneously. Among these phenols, m-cresol, p-cresol, 3,5-xylenol, 2,
3,5-trimethylphenol is preferred. Aldehydes include formaldehyde, paraformaldehyde, trioxane, formalin and the like. These condensation products of phenols and aldehydes can be produced by a known method in the presence of an acidic catalyst. Hydrochloric acid, sulfuric acid, formic acid, acetic acid, oxalic acid, p-toluenesulfonic acid and the like can be used as the acidic catalyst at that time. The weight average molecular weight of the alkali-soluble novolak resin suitable for the present invention is 3,000 to 25,000, preferably,
It is preferable to be in the range of 5,000 to 20,000.
Here, the weight average molecular weight is a value in terms of polystyrene determined by a gel permeation chromatography method.
In particular, in order to obtain a high-resolution, good resist pattern shape at low cost in a thin-film resist process, m-cresol novolak resin having a weight average molecular weight of 5,000 to 10,000 formed by condensation from only m-cresol in the presence of an acidic catalyst , A weight-average molecular weight of 5,000 to 20,000 formed by condensing a mixed cresol of m-cresol 20 to 80 mol% and p-cresol 20 to 80 mol% in the presence of an acidic catalyst.
Is preferred.

The component (C) is a compound having at least one acid dissociable, dissolution inhibiting group and capable of dissociating the dissolution inhibiting group by the action of an acid generated from the component (A) to generate an organic carboxylic acid. Such compounds are described in the above (1) to (4)
Prior art, JP-A-6-287163, JP-A-6-287163
-285918, JP-A-8-193052, JP-A-8-193054, JP-A-8-19305
No. 5, JP-A-8-245515 and JP-A-9-77720 have been proposed so far, and their use is not particularly limited. The acid-dissociable, dissolution-inhibiting group can be arbitrarily selected from those known so far in chemically amplified positive resists. It is divided into two cases: protection with a dissolution-inhibiting group and two cases. Specifically, such an acid dissociable, dissolution inhibiting group includes a tertiary alkyloxycarbonyl group such as a tert-butyloxycarbonyl group and a tert-amyloxycarbonyl group;
tert-butyloxycarbonylmethyl group, tert-
Tertiary alkyloxycarbonylalkyl groups such as butyloxycarbonylethyl; tert-butyl,
tertiary alkyl groups such as tert-amyl group; cyclic ether groups such as tetrahydropyranyl group and tetrahydrofuranyl group; alkoxyalkyl groups such as ethoxyethyl group and methoxypropyl group; 1-methylcyclohexyl group and 1-ethylcycloalkyl A 1-lower alkylmonocycloalkyl group such as a group, a 1-methyladamantyl group,
Preferred are 1-alkylcycloalkyl groups such as 1-lower alkylpolycycloalkyl groups such as 1-ethyladamantyl group. Among them, tert-
A butyloxycarbonyl group, a tert-butyloxycarbonylmethyl group, a tert-butyl group, a tetrahydropyranyl group, an ethoxyethyl group, a 1-methylcyclohexyl group and a 1-ethylcyclohexyl group are preferred.
Examples of the acid dissociable, dissolution inhibiting group for the phenolic hydroxyl group include the above-described acid dissociable, dissolution inhibiting groups other than the 1-alkylcycloalkyl group. Examples of the acid dissociable, dissolution inhibiting group for a carboxyl group include the above-described acid dissociable, dissolution inhibiting groups other than the tertiary alkyloxycarbonyl group. However, the component (C) needs to be capable of generating an organic carboxylic acid by dissociation of the dissolution inhibiting group by the action of an acid generated from the component (A). When the phenolic hydroxyl group is protected with the above-mentioned dissolution inhibiting group to obtain the component (C), at least one of the phenolic hydroxyl groups needs to use a carboxylic acid-generating group such as a tertiary alkyloxycarbonylalkyl group. When the carboxyl group is protected from the compound having at least one carboxyl group by the dissolution inhibiting group to obtain the component (C), the compound can be arbitrarily selected from the dissolution inhibiting groups.

The more preferred component (C) is that the (c-1) weight average molecular weight is 10 since high resolution and a good resist pattern shape can be obtained at low cost by a thin film resist process.
0 to 1500, or (c-2) a polymer having at least 2 mol% or more of (meth) acrylic acid derivative units having an acid dissociable, dissolution inhibiting group, and having a weight average molecular weight of 2,000 to 20,000. A range of polymers are included.

The component (c-1) is preferably a bile acid ester having at least one acid dissociable, dissolution inhibiting group such as cholic acid, deoxycholic acid, ursocholic acid and lithocholic acid, or a substituted or unsubstituted ester. Compounds having 1 to 6 benzene nuclei and having at least one acid-dissociable, dissolution-inhibiting group can be dissociated by the action of an acid generated from the component (A) to generate an organic carboxylic acid. Can be The former bile acid ester is particularly suitable for a photosensitive substrate for an F ₂ laser, a method for forming a resist pattern, and a positive resist composition. The latter component (c-1) can be divided into the following (i), (ii) and (iii). (i) A phenolic compound such as bisphenol A or trisphenols and a tertiary alkyl ester of a halogenated fatty acid such as tert-butyl acetate bromoacetate are subjected to a dehydrohalogenation reaction in the presence of an alkali catalyst to give phenol. A compound in which a hydrogen atom of a labile hydroxyl group is substituted with a tertiary alkyloxycarbonylalkyl group.
When the compound has a plurality of hydroxyl groups, it may be substituted with an acid dissociable, dissolution inhibiting group other than the tertiary alkyloxycarbonylalkyl group. (ii) A compound in which a carboxyl group-containing compound such as biphenyldicarboxylic acid, naphthalenedicarboxylic acid, or benzophenonedicarboxylic acid is substituted with an acid dissociable, dissolution inhibiting group. (iii) A compound having a carboxyl group and a hydroxyl group, such as 4,4'-bis (4-hydroxyphenyl) pentanoic acid, in which a carboxyl group or a hydroxyl group is substituted with the acid dissociable, dissolution inhibiting group. In this case, it may be substituted with a different kind of acid dissociable, dissolution inhibiting group.

Many phenolic compounds in (i) are already known as the phenolic compound used for the sulfonic acid ester in the above-mentioned non-chemically amplified positive resist, and as a sensitivity improver to be incorporated in the positive resist. And any of these can be used. For example, bis (4-hydroxyphenyl) methane, bis (2,3,4-trihydroxyphenyl) methane, 2- (4-hydroxyphenyl) -2- (4′-hydroxyphenyl) propane, 2- (2 3,4-trihydroxyphenyl) -2- (2 ', 3', 4'-trihydroxyphenyl) propane, tris (4-hydroxyphenyl) methane, bis (4-hydroxy-3,5-
Dimethylphenyl) -2-hydroxyphenylmethane,
Bis (4-hydroxy-2,5-dimethylphenyl)-
2-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -3,4-dihydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -3,4-dihydroxyphenylmethane, Bis (4-hydroxy-3-methylphenyl)-
3,4-dihydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxy-6-methylphenyl)-
4-hydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxy-6-methylphenyl) -3,4
-Dihydroxyphenylmethane, 1- [1- (4-hydroxyphenyl) isopropyl] -4- [1,1-bis (4-hydroxyphenyl) ethyl] benzene, phenol, m-cresol, p-cresol or xylenol 2, 3 of formalin condensates of phenols
Tetranuclear and the like. As the carboxyl group-containing compound in (ii), any of known carboxylic acid compounds can be used. For example, cyclohexane carboxylic acid, benzoic acid, salicylic acid, biphenyl polycarboxylic acid, naphthalene (di) carboxylic acid, naphthalene triacetic acid, benzoyl benzoic acid, anthracene carboxylic acid,
Benzophenone dicarboxylic acid, 1-naphthylacetic acid, a compound represented by the following formula,

[0020]

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And the like. As the compound having both a carboxyl group and a hydroxyl group in (iii), any of known compounds can be used. For example, 2,
2′-bis (4-hydroxyphenyl) propanoic acid,
4,4'-bis (4-hydroxyphenyl) pentanoic acid, and the like.

More preferably, the latter (c-1) is (c-1-1) which inhibits the hydrogen atom of at least one hydroxyl group or carboxyl group of the compound represented by the following general formula (I) from undergoing acid dissociable dissolution. A compound substituted with a group, (c-1)
-2) a condensate of formaldehyde with at least one selected from phenol, m-cresol, p-cresol and xylenol, wherein at least one of the hydrogen atoms of the hydroxyl group is substituted with a tert-butyloxycarbonylalkyl group Divided into These (c-1-1) and (c-1-2) are preferable because they make the positive resist composition high in contrast and further improve the resist pattern shape and resolution.

[0023]

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[Wherein, R ^{1 to} R ⁴ each independently represent a hydrogen atom, a linear, branched or cyclic alkyl group having 6 or less carbon atoms, a lower alkoxy group, a hydroxyl group, a carboxyl group, a carboxyl group-containing group; alkyl group, X is a single bond, -C (O) -, - C (R 5) (R 6) - is any one of, R ⁵ is a hydrogen atom or a lower alkyl group, R ⁶
Is a hydrogen atom, a lower alkyl group, a carboxyl group, a carboxyl group-containing alkyl group or an aryl group represented by the following general formula (II) (R ^{1 to} R ⁴ in the formula (II) are the same as defined above) A), q is 0 or 1, and when q is 0, the group in parentheses is a hydrogen atom. ]

[0025]

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Examples of the linear, branched or cyclic alkyl group having 6 or less carbon atoms in R ^{1 to} R ⁶ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group and an n-alkyl group.
Examples thereof include a butyl group, a sec-butyl group, a tert-butyl group, a cyclopentyl group, and a cyclohexyl group.
As the lower alkoxy group, a methoxy group, an ethoxy group,
And a propoxy group. Examples of the lower alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group and a tert-butyl group. The carboxyl group-containing alkyl group is a carboxyl group bonded to an alkylene group having 1 to 10 carbon atoms. Examples of the alkylene group include a methylene group, an ethylene group, a linear or branched propylene group, and a butylene group. , A hexylene group, a heptylene group, a nonylene group and the like.

Specific examples of the latter component (c-1) in the present invention include the following compounds.

[0028]

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[0029]

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[0030]

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[0031]

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The component (c-2) is a polymer having at least 2 mol% or more of a (meth) acrylic acid derivative unit having an acid dissociable, dissolution inhibiting group and having a weight average molecular weight in the range of 2,000 to 20,000. One component. As the component (c-2), (1) a polymer having at least the (meth) acrylic acid derivative unit and hydroxy (α-methyl) styrene unit used as a base resin component of a KrF positive resist; 2) a copolymer having at least a unit derived from a polycyclic olefin having an acid dissociable, dissolution inhibiting group and a unit derived from maleic anhydride used as a base resin component of an ArF positive resist; An acrylic polymer containing the (meth) acrylic acid derivative unit and having no hydroxy (α-methyl) styrene unit, which is also used as the base resin component of the ArF positive resist. The above (1) to (3)
Will be described in detail. (1) A polymer having at least a (meth) acrylic acid derivative unit having an acid dissociable, dissolution inhibiting group and a hydroxy (α-methyl) styrene unit. Other copolymerizable monomers forming the polymer include styrene, (meth) acrylic acid, and alkyl esters of (meth) acrylic acid such as methyl, ethyl and butyl. Such a polymer is, for example, a copolymer composed of (c-2-1) hydroxy (α-methyl) styrene unit and (c-2-2) (meth) acrylic acid derivative unit having an acid dissociable, dissolution inhibiting group. And a terpolymer comprising (c-2-1), (c-2-2) and styrene. In the latter terpolymer, the (c-2-1) unit is 50-85 mol%, and the (c-2-2) unit and the styrene unit are each 2- (mol).
It is preferable to copolymerize at a rate of 30 mol%. Above all, because of high contrast and excellent resist pattern shape and resolution, (c-2-1) hydroxy (α-methyl) styrene unit 50-70 mol% and (c-2-2) acid dissociable dissolution inhibition. A copolymer consisting of 30 to 50 mol% of a (meth) acrylic acid derivative unit having a group is preferred. When the amount of the (c-2-2) unit is larger than this range, the solubility in the developing solution is deteriorated. As the acid dissociable, dissolution inhibiting group in the (c-2-2) unit, the same groups as those described in the description of the component (c-1) are used, and tert-butyl (meth) acrylate is preferable. And units derived therefrom.

(2) A copolymer containing at least a unit derived from a polycyclic olefin having an acid dissociable, dissolution inhibiting group and a unit derived from maleic anhydride. As the polycyclic olefin, for example, bicyclo [2.2.1] -2
-Heptene (norbornene) or tetracyclo [4.4.
0.1 ^2,5 . 1 ^7,10] -3-polycyclic a formula include those having an ethylenic double bond such as dodecene, units derived from polycyclic olefins having an acid dissociable dissolution inhibiting group, later As described above, it is synthesized from a (meth) acrylic acid ester having an acid dissociation-suppressing group by a Diels-Alder reaction, and thus corresponds to the component (c-2) of the present invention. Preferably, at least the following general formula (VII)
Or a unit represented by the following general formula (VIII)
A copolymer containing a unit represented by

[0034]

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Wherein R ¹¹ represents a hydrogen atom or a lower alkyl group (for example, having 1 to 3 carbon atoms), Y represents an acid dissociable group, and n is 0 or 1.

[0036]

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Wherein R ¹¹ is the same as above, R ¹² is an alkyl group having at least one hydroxy, and m is 0 or 1.

In the general formula (VII), Y is the above-mentioned acid-dissociable group except for an ester moiety.
Particularly preferred are tertiary alkyl groups such as tert-butyl group, 1-methyl-1-cyclohexyl group and 1-ethyl-1-cyclohexyl group; cyclic ether groups such as tetrahydropyranyl group; Is preferred because a 1-ethyl-1-cyclohexyl group has high sensitivity and can be easily synthesized at low cost.

In the general formula (VIII), R ¹² is a functional group for improving the adhesion between the silicon wafer or the silicon wafer provided with the inorganic film and the resist layer, and is an alkyl group having at least one hydroxyl group. In this case, although not particularly limited, for example, a lower monohydroxyalkyl group or a lower dihydroxyalkyl group having 1 to 10 carbon atoms and having one or two hydroxy groups is preferable. Specifically, hydroxymethyl group, hydroxyethyl group, hydroxypropyl group, hydroxybutyl group, dihydroxybutyl group, hydroxypentyl group and the like, especially 2-hydroxypropyl,
A 2,3-dihydroxybutyl group is preferred. General formula (VI
The unit represented by (I) or (VIII) is an acid dissociable, dissolution inhibiting group-containing acrylic acid or methacrylic acid ester and cyclopentadiene or dicyclopentadiene.
The product obtained by the s-Alder reaction is dissolved in maleic anhydride and a suitable organic solvent such as dioxane and tetrahydrofuran, and benzoyl peroxide, 2,2′-azobisisobutyronitrile, acetyl peroxide, lauryl are dissolved. It can be obtained by adding a radical polymerization initiator such as peroxide and copolymerizing. In this case, when cyclopentadiene is used, n and m correspond to 0,
When dicyclopentadiene is used, this corresponds to the case where n and m are 1.

The copolymerization ratio of maleic anhydride and polycyclic olefin monomer having an acid dissociable group in the general formula (VII) or (VIII) is theoretically 50 mol% each. However, since maleic anhydride and polycyclic olefin monomers are actually copolymerized, the actual copolymerization ratio is 40 to 6 units derived from maleic anhydride.
0 mol%, 40 to 60 mol% of units derived from a polycyclic olefin monomer. The general formulas (VII) and (V
In the case of the copolymer of III), the units 40 to 40 of the general formula (VII)
90 mol%, preferably 50 to 80 mol%, of the general formula (VI
The unit of II) is 10 to 60 mol%, preferably 20 to 50 mol%. When the unit of the general formula (VII) is less than these ranges, the sensitivity is lowered, and when it is too large, the adhesion to the substrate is poor. The weight average molecular weight of the copolymer (2) is 2,000
0-20,000, preferably 3,000-6,000
Range is good.

(3) An acrylic polymer containing a (meth) acrylic acid unit having an acid dissociable, dissolution inhibiting group and not having a hydroxy (α-methyl) styrene unit. As the acrylic polymer (3), an acrylic or methacrylic polymer or copolymer containing a structural unit represented by the following general formula (IX) is used.

[0042]

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The structural unit represented by the general formula (IX) is represented by the following general formula (X)

[0044]

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(Wherein R ¹³ is a hydrogen atom or a methyl group;
R ¹⁴ and R ¹⁵ are each a lower alkyl group, and R ¹⁶ is a residue formed by removing one hydrogen atom bonded to a carbon atom of a compound selected from a lactone compound, a ketone compound and an ester compound. , 1 is 0 or 1) derived from an acrylate or methacrylate. This acrylate or methacrylate is obtained by esterifying acrylic acid or methacrylic acid with a corresponding alcohol or the like, is inexpensive, can be easily produced, and is suitable for mass production. In the general formulas (IX) and (X), the lower alkyl group represented by R ¹⁴ and R ¹⁵ is preferably a straight-chain or branched alkyl group having 1 to 4 carbon atoms. Group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group,
Examples thereof include a sec-butyl group and a tert-butyl group. Preferably, R ¹⁴ and R ¹⁵ are both methyl groups. On the other hand, the residue formed by removing one hydrogen atom bonded to the carbon atom of the lactone compound in R ¹⁶ includes a γ-butyrolactone residue, a δ-valerolactone residue and a derivative residue thereof. Preferred are mentioned.
Here, the derivative may be a lower alkyl substituent such as a methyl group or an ethyl group, a lower alkoxy substituent such as a methoxy group or an ethoxy group, a compound having a plurality of oxygen atoms on a lactone ring, a methoxycarbonyl group or an acyl group on a lactone ring. Are bonded. Among these, a γ-butyrolactone residue and a γ-butyrolactone residue having a lower alkyl group or a lower alkoxy group are preferred. In the acrylate or methacrylate represented by the general formula (X), examples of the alcohol component having the lactone compound residue include:

[0046]

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Compounds represented by the following formulas can be mentioned. Of these, alcohols having a 5-membered lactone residue are preferred. The residue formed by removing one hydrogen atom bonded to the carbon atom of the ketone compound in R ¹⁶ is preferably a ketone compound residue having 2 to 10 carbon atoms, particularly preferably an acetonyl group. In the acrylate or methacrylate represented by the general formula (X), examples of the alcohol component having the ketone compound residue include:

[0048]

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4-hydroxy-4-methyl-2-pentanone (diacetone alcohol) represented by the following formula: Further, the residue formed by removing one hydrogen atom bonded to the carbon atom of the ester compound in R ¹⁶ includes, for example, a lower alkoxycarbonyl group such as a methoxycarbonyl group, an ethoxycarbonyl group, and a propoxycarbonyl group; A lower alkoxycarbonylmethyl group; In the acrylate or methacrylate represented by the general formula (X), the alcohol component having the ester compound residue includes, for example, a general formula

[0050]

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(Wherein R ¹⁷ is a lower alkyl group), such as an alkyl 2-hydroxy-2-methylpropionate, is preferred. (3) The acrylic polymer contains the structural unit represented by the general formula (IX) in an amount of 20 to
Those containing at a ratio of 80 mol%, preferably 40 to 70 mol% are preferable because they improve sensitivity, resolution, transparency, adhesion and affinity for alkali in a well-balanced manner. (3) The acrylic polymer may be a polymer obtained by polymerizing the (meth) acrylic acid ester represented by the general formula (X), but the (meth) acrylic polymer represented by the general formula (X) may be used. A monomer obtained by copolymerizing an acrylic acid ester and another monomer shown below such that the proportion of the structural unit represented by the general formula (IX) falls within the above range is preferable. As the other monomer to be copolymerized, for example, a (meth) acryl having a protective group such as a known dry etching resistance improving group or an acid dissociable group conventionally used in a chemically amplified positive photoresist for ArF is used. Acid derivatives (hereinafter referred to as first monomers); known as carboxylic acids having an ethylenic double bond (hereinafter referred to as second monomers) for making them alkali-soluble such as (meth) acrylic acid, maleic acid, fumaric acid, and acrylic resins (Hereinafter, referred to as a third monomer). These other monomers may be used in appropriate combination.
Examples of the first monomer include tert-butyl (meth) acrylate, tetrahydropyranyl (meth) acrylate, tetrahydrofuranyl (meth) acrylate,
1-methylcyclohexyl (meth) acrylate, 1-methyladamantyl (meth) acrylate, ethoxyethyl (meth) acrylate, methoxypropyl (meth) acrylate, (meth) acrylic acid and 2-hydroxy-3-pinanone (Meth) acrylates in which the hydroxyl group of a carboxyl group such as an ester is protected by an acid-dissociable substituent, or adamantyl (meth) acrylate, cyclohexyl (meth) acrylate, naphthyl (meth) acrylate,
Benzyl (meth) acrylate, 3- (meth) acrylic acid
Oxocyclohexyl, bicyclo [2,2,1] heptyl (meth) acrylate, tricyclodecanyl (meth) acrylate, ester of (meth) acrylic acid and terpineol, (meth) acrylic acid and 3-bromoacetone And the like in which a hydroxyl group of a carboxyl group such as an ester is protected with an acid non-dissociable substituent. Such a first monomer has, for example, the general formula

[0052]

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(Wherein R ¹⁸ is a hydrogen atom or a methyl group,
Z is a tert-butyl group, an ethoxyethyl group, a methoxypropyl group, a terpineol residue or

[0054]

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Which is a group represented by Examples of the second monomer include, for example, (meth) acrylic acid, maleic acid, fumaric acid, etc., of which (meth) acrylic acid is preferable. In addition, the third
Examples of the monomer include (a) methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, (meth)
N-butyl acrylate, isobutyl (meth) acrylate, n-hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, (meth) acrylic acid Alkyl esters such as 2-hydroxyethyl and 2-hydroxypropyl (meth) acrylate, (b) (meth)
Examples include amides such as acrylamide, N-methylol (meth) acrylamide, and diacetone acrylamide; (c) acrylonitrile, methacrylonitrile, vinyl chloride, and ethyl vinyl ether. (3)
Examples of the acrylic polymer include a copolymer obtained by polymerizing a monomer represented by the general formula (X) and at least one selected from the first, second, and third monomers. preferable. Of the polymers of (1), (2) and (3),
(1) is preferable because it can be easily and inexpensively obtained.

The mixing ratio of the component (C) is 10
It is 10 to 400 parts by weight with respect to 0 parts by weight. (C-
When the low molecular weight component (1) is used, the component (B) 10
It is preferable to use 10 to 50 parts by weight with respect to 0 part by weight because a resist pattern having high resolution and excellent dry etching resistance can be obtained. On the other hand, when the polymer of the component (c-2) is used, 20 to 200 parts by weight per 100 parts by weight of the component (B) is used.
When used in parts by weight, a resist pattern having high resolution and excellent dry etching resistance is obtained, which is preferable.

The positive resist composition of the present invention may contain various additives as required.
Examples of the additive include (D) an aliphatic lower amine for improving a known time delay (stability after lapse of time after exposure) and (E) an organic carboxylic acid for improving sensitivity reduction and substrate dependency. Or oxo acid of phosphorus or its derivative.

As the aliphatic lower amine, diethylamine, triethylamine, n-propylamine, di-n-
Propylamine, tri-n-propylamine, triisopropanolamine, isopropylamine, tributylamine, tripentylamine, triethanolamine,
Dipropanolamine, tripropanolamine and the like can be mentioned. Among them, tertiary aliphatic lower amines are preferred. Examples of the organic carboxylic acid include, but are not particularly limited to, organic carboxylic acids such as saturated or unsaturated aliphatic carboxylic acids, alicyclic carboxylic acids, and aromatic carboxylic acids. Examples of the saturated aliphatic carboxylic acid include monovalent or polyvalent carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, and adipic acid. Examples of the unsaturated aliphatic carboxylic acid include acrylic acid, crotonic acid, isocrotonic acid, 3-butenoic acid, methacrylic acid, 4-pentenoic acid, propiolic acid, 2-butyric acid, maleic acid, fumaric acid, acetylene carboxylic acid, and the like. No. Examples of the alicyclic carboxylic acid include 1,1-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and 1,1-cyclohexyldiacetic acid. Can be As the aromatic carboxylic acid, p-hydroxybenzoic acid, o-hydroxybenzoic acid, 2-hydroxy-3-
Aromatic carboxylic acids having a substituent such as a hydroxyl group such as nitrobenzoic acid, phthalic acid, terephthalic acid and isophthalic acid, a nitro group, a carboxyl group and the like can be mentioned. Specific examples of the oxo acid of phosphorus or a derivative thereof include a derivative such as phosphoric acid or phosphorous acid such as phosphoric acid, phosphorous acid, di-n-butyl phosphate, diphenyl phosphate, or a derivative thereof such as phosphonic acid. Acids, phosphonic acid dimethyl ester, phosphonic acid di-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester, phosphonic acid dibenzyl ester, etc., phosphonic acids and derivatives thereof such as esters, phosphinic acid, phenylphosphinic acid, etc. Derivatives such as phosphinic acids and their esters include, but are not limited to.

(D) The mixing ratio of the aliphatic amine is (B)
The amount is preferably 0.01 to 1.0 part by weight, preferably 0.05 to 0.5 part by weight, per 100 parts by weight of the component. Within this range, the resist pattern shape and sensitivity are improved, which is preferable. The compounding ratio of the (E) organic carboxylic acid or oxo acid of phosphorus or a derivative thereof is 0.01 to 1.0 part by weight, preferably 0.05 to 1.0 part by weight, per 100 parts by weight of the component (B).
0.5 parts by weight is preferred. Within this range, the resolution and sensitivity are improved, which is preferable.

The positive resist composition of the present invention may further contain, if necessary, compatible additives such as an antihalation agent and a surfactant.

The positive resist composition according to the present invention comprises:
It is preferable that each of the above components is dissolved in an appropriate solvent and used in the form of a solution. Examples of such a solvent include solvents used in conventional positive photoresist compositions, for example, ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone and 2-heptanone; ethylene glycol, propylene glycol , Diethylene glycol, ethylene glycol monoacetate, propylene glycol monoacetate,
Diethylene glycol monoacetate or polyhydric alcohols such as monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether and derivatives thereof; cyclic ethers such as dioxane; and ethyl lactate, methyl acetate; Ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate,
Esters such as ethyl ethoxypropionate can be mentioned. These may be used alone or as a mixture of two or more.

A preferred method of using the photosensitive substrate and the positive resist composition in the present invention is as follows: a silicon wafer, polycrystalline silicon, TiN, SiON, PSG, and the like provided on the wafer in accordance with various semiconductor elements. BPS
A solution of a positive resist composition is applied on a substrate or the like on which various thin films such as G, SiN, and Si ₃ N ₄ are provided by a spinner or the like, and dried to form a photosensitive layer. Thus, a photosensitive substrate is obtained. Next, exposure is performed through a photomask on which a pattern is drawn. Next, this is heated after exposure (P
After EB), when developing with a developing solution, for example, an alkaline aqueous solution such as an aqueous solution of 1 to 10% by weight of tetramethylammonium hydroxide (TMAH), an exposed portion is dissolved and removed, and an image (resist pattern) faithful to the mask pattern is formed. Obtainable. In order to further improve the resolution of the resist pattern, an inorganic or organic antireflection film may be interposed between the substrate and the photosensitive layer obtained by using the composition of the present invention. At this time, the thickness of the antireflection film is generally in the range of 30 to 300 nm.

According to the present invention, a resist pattern can be formed by a conventional lithography process using a short-wavelength light of KrF excimer laser or F ₂ laser or less using the above positive resist composition. . That is, the photosensitive substrate, selective exposure by KrF excimer laser or F ₂ laser following short-wavelength light, resist pattern by sequentially performing exposure baking and alkali developing can be formed. However,
The thickness of the resist layer provided on the substrate is 500 to 5800
Å, preferably 500〜5000Å, more preferably 500〜4000Å, and most preferably 500〜3000Å. The thinner the resist layer is, the better the effects of the present invention are exhibited, which is preferable. 500 film thickness
If it is less than Å, the dry etching resistance of the resist pattern is undesirably small. Conversely, if it exceeds 5800 °, the resolution and the cross-sectional shape deteriorate, which is not preferable. Also,
When the film thickness is 4500 to 5500 °, it is suitable as a resist for ion plantation which requires particularly high dry etching resistance. Note that the photosensitive substrate of the present invention is preferably used by selecting its film thickness by exposure light.
If it is a KrF excimer laser, 1000 to 5800
Å, preferably 1000-5000Å, more preferably 1000-4000Å, optimally 1000-3000
厚 thickness is preferred. If F ₂ laser following short-wavelength light, 500-1000, preferably 500 to 900
厚 thickness is preferred. In the case of such an ultra-thin film,
By providing a hard mask layer as an etching stopper layer between the resist layer and the layer to be etched on the substrate, a fine resist pattern of 0.15 μm or less can be applied.

[0064]

The present invention will be further described below with reference to examples and comparative examples. Example 1 (A) component bis (4-tert-butylphenyl) iodonium nonafluorobutanesulfonate 2.67 parts by weight (B) component m-cresol 40 mol% and p-cresol 60 mol%
Of cresol novolak resin having a weight average molecular weight of 18,000 obtained by condensation of cresol mixed with oxalic acid catalyst with formalin 100 parts by weight of component (C) bis (3-cyclohexyl-4-hydroxy-6-methylphenyl) -4-hydroxy 20 mole parts of a compound obtained by reacting 2 moles of bromoacetic acid tert-butyl ester with 1 mole of phenylmethane and substituting a part of hydroxyl groups with tert-butyloxycarbonylmethyloxy (D) 0.27 weight parts of triethanolamine (D) E) Component 0.27 parts by weight of salicylic acid The above components (A) to (E) are combined with methyl amyl ketone 1070
After being dissolved in parts by weight, the solution was filtered through a membrane filter having a pore size of 0.2 μm to obtain a positive resist solution. On the other hand, the positive type resist solution was spin-coated on a 6-inch silicon wafer treated with hexamethyldisilazane, and dried on a hot plate at 90 ° C. for 90 seconds to form a resist layer having a thickness of 2500 °. Next, after selectively irradiating a KrF excimer laser with a reduction projection exposure apparatus FPA-3000EX3 (manufactured by Canon Inc., NA = 0.6), PEB is used at 110 ° C. for 90 seconds.
After that, a positive resist pattern was obtained by paddle development with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 60 seconds. In this way, a 0.20 μm line and space pattern was resolved, and the resist pattern shape was a good shape that stood vertically from the substrate. The minimum exposure (sensitivity) required to obtain a 0.20 μm resist pattern is 3
It was 1 mJ / cm ² . The limit resolution is 0.18
μm. The dry etching resistance was also good.

Example 2 A resist patterning process was performed in the same manner as in Example 1 except that the resist film thickness was changed to 1800 °. As a result, a 0.20 μm line-and-space pattern was resolved, and the resist pattern shape was a good shape that stood vertically from the substrate. The minimum exposure (sensitivity) required to obtain a 0.20 μm resist pattern was 28 mJ / cm ² . In addition, the limit resolution was 0.17 μm. The dry etching resistance was also good.

Example 3 In Example 1, the component (C) was replaced with 3,4,3 ', 4'-
A positive resist solution was prepared in the same manner as in Example 1 except that 20 parts by weight of a compound in which all of the carboxyl groups of biphenyltetracarboxylic acid were substituted with a tert-butyl group ester was used. Next, a resist patterning process was performed under the same conditions as in Example 1. As a result, a 0.20 μm line-and-space pattern was resolved, and the resist pattern shape was a taper shape that did not hinder. The minimum exposure (sensitivity) required to obtain a 0.20 μm resist pattern was 50 mJ / cm ² . Further, the limit resolution was 0.18 μm. The dry etching resistance was also good.

Example 4 A positive electrode was prepared in the same manner as in Example 1 except that the component (C) was replaced with 50 parts by weight of a compound in which the carboxyl group of benzoic acid was substituted with 1-ethoxyethyloxycarbonyl group. A mold resist solution was prepared. Next, a resist patterning process was performed under the same conditions as in the example. As a result, a 0.20 μm line-and-space pattern was resolved, and the resist pattern shape was a taper shape that did not hinder. The minimum exposure (sensitivity) required to obtain a 0.20 μm resist pattern is 32 mJ /
cm ² . The limit resolution was 0.19 μm. The dry etching resistance was also good.

Example 5 In Example 1, the component (C) was replaced with the compound 2 of the following structural formula.
A positive resist solution was prepared in the same manner as in Example 1 except that the amount was changed to 0 parts by weight. Next, a resist patterning process was performed under the same conditions as in the example. As a result 0.20 μm
The line and space pattern was resolved, and the resist pattern shape was a good shape that stood vertically from the substrate. The minimum exposure (sensitivity) required to obtain a 0.20 μm resist pattern is 40 mJ / cm ^2.
Met. In addition, the limit resolution was 0.17 μm.
The dry etching resistance was also good.

[0069]

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Example 6 A resist patterning process was performed under the same conditions as in Example 1 except that the resist film thickness was changed to 0.5 μm. As a result, a 0.25 μm line and space pattern was resolved, and the resist pattern was trapezoidal. The minimum exposure (sensitivity) required to obtain a 0.25 μm resist pattern is 40 mJ / cm.
^{Was 2} . Further, the limit resolution was 0.20 μm. The dry etching resistance was also good.

Example 7 Component (A) 2.67 parts by weight of bis (4-tert-butylphenyl) iodonium nonafluorobutanesulfonate Component (B) 60 mol% of m-cresol and 40 mol% of p-cresol
Of cresol novolak resin having a weight average molecular weight of 23,000 obtained by condensation of cresol mixed with formalin under oxalic acid catalyst 50 parts by weight of component (C) Copolymer of hydroxystyrene unit 60 mol% and tert-butyl acrylate unit 40 mol% 50 parts by weight of a copolymer having a weight average molecular weight of 12,000 (D) component 0.12 parts by weight of triethanolamine (E) component 0.12 parts by weight of salicylic acid The above components (A) to (E) are replaced with methyl amyl ketone. 1070
After being dissolved in parts by weight, the solution was filtered through a membrane filter having a pore size of 0.2 μm to obtain a positive resist solution. On the other hand, the positive resist solution was spin-coated on a 6-inch silicon wafer that had been treated with hexamethyldisilazane, and dried on a hot plate at 100 ° C. for 60 seconds to form a resist layer having a thickness of 5400 °. Next, after selectively irradiating a KrF excimer laser with a reduction projection exposure apparatus FPA-3000EX3 (manufactured by Canon Inc., NA = 0.6), PEB at 110 ° C. for 60 seconds.
After that, a positive resist pattern was obtained by paddle development with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 60 seconds. In this way, a 0.30 μm line-and-space pattern was resolved, and the resist pattern shape was a good shape that stood vertically from the substrate, but some standing waves were observed.
The minimum exposure (sensitivity) required to obtain a 0.30 μm resist pattern was 17 mJ / cm ² . Further, the limit resolution was 0.20 μm. The dry etching resistance was also good.

Example 8 Component (A) 100 parts by weight of the same cresol novolak resin as the component (B) used in Example 1 (B) Component 3 parts by weight of triphenylsulfonium trifluoromethanesulfonate (Component (C) The following compound)

[0073]

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25 parts by weight Other components 0.3 parts by weight of triisopropanolamine

After dissolving the above components (A), (B), (C) and other components in 1660 parts by weight of propylene glycol monomethyl ether monoacetate, a pore diameter of 0.1 μm
To obtain a solution of the positive resist composition. A solution of the positive resist composition was spin-coated on a 6-inch silicon wafer and dried on a hot plate at 90 ° C. for 90 seconds,
A resist layer having a thickness of 800 ° was formed. Next, after selectively irradiating an F ₂ excimer laser (157 nm) with a contact exposure apparatus VUVES-4500 (manufactured by Litho Tech Japan), heating was performed at 110 ° C. for 90 seconds (PE).
B) Treatment and paddle development with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide at 23 ° C. for 60 seconds. Then, the substrate was rinsed with pure water for 30 seconds to obtain a positive resist pattern. In this way, a 180 nm line and space pattern was obtained. At that time, the exposure amount was 3 mJ / cm ² , and the cross-sectional shape was a good one close to a rectangle. The SEM resistance and the dry etching resistance were also good.

Example 9 A positive resist composition solution was obtained in the same manner as in Example 8, except that the component (C) was replaced with the same amount of tert-butyl lithocholic acid. Was. Next, when resist patterning was performed in the same manner as in Example 8, a line and space pattern of 180 nm was obtained, and the exposure amount was 3 m
J / cm ² , and the cross-sectional shape was good and nearly rectangular. The SEM resistance and the dry etching resistance were also good.

Comparative Example 1 A resist patterning process was performed under the same conditions as in Example 1 except that the resist film thickness was changed to 0.7 μm. As a result, a 0.35 μm line and space pattern was resolved, and the resist pattern shape was a defective triangular shape. The minimum exposure amount (sensitivity) required to obtain a 0.35 μm resist pattern is 50 m.
J / cm ² . The limit resolution is 0.28 μm
Met.

[0078]

According to the present invention, it is inexpensive, has excellent resist pattern shape and dry etching resistance, has high resolution, and has excellent SEM resistance, especially for KrF laser or short wavelength not more than F ₂ laser. A photosensitive substrate for light, a method for forming a resist pattern using the same, and a positive resist composition are provided.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C08L 101/06 C08L 101/06 G03F 7/004 501 G03F 7/004 501 H01L 21/027 H01L 21/30 502R (72) Inventor Kazuyuki Nitta 150 Nakamurako, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Tokyo Ohka Kogyo Co., Ltd.

Claims (30)

[Claims] A resist layer is formed on a substrate in a range of 500 to 5800.
(A) a compound capable of generating an acid upon irradiation with radiation, (B) an alkali-soluble novolak resin, and (C) A positive resist composition containing a compound having at least one acid dissociable, dissolution inhibiting group and capable of generating an organic carboxylic acid by dissociation of the dissolution inhibiting group by the action of an acid generated from the component (A); A photosensitive substrate characterized by the following. 2. The photosensitive substrate according to claim 1, wherein the resist layer has a thickness of 500 to 4000 °. 3. The photosensitive substrate according to claim 1, wherein the component (C) is (c-1) a compound having a weight-average molecular weight of 100 to 1500. 4. The photosensitive composition according to claim 3, wherein the component (c-1) is a compound having 1 to 6 substituted or unsubstituted benzene nuclei and having at least one acid dissociable, dissolution inhibiting group. Base material. 5. The component (c-1) is a bile acid ester having at least one acid dissociable, dissolution inhibiting group.
3. The photosensitive substrate according to item 1. 6. A component (c-1) wherein (c-1-1) an acid dissociable, dissolution inhibiting group having at least one hydroxyl or carboxyl hydrogen atom of a compound represented by the following general formula (I): The photosensitive substrate according to claim 4, which is a compound substituted with: Embedded image [Wherein, R ^{1 to} R ⁴ each independently represent a hydrogen atom, a linear, branched or cyclic alkyl group having 6 or less carbon atoms, a lower alkoxy group, a hydroxyl group, a carboxyl group, or a carboxyl group-containing alkyl group. X is a single bond, —C (O) —, or —C (R ⁵ ) (R ⁶ ) —, R ⁵ is a hydrogen atom or a lower alkyl group, R ⁶ is a hydrogen atom, a lower An alkyl group, a carboxyl group, a carboxyl group-containing alkyl group or an aryl group represented by the following general formula (II) (R ¹ to R ¹ in the formula (II))
R ⁴ is the same as defined above), q is 0 or 1, and when q is 0, the group in parentheses is a hydrogen atom. ] 7. The component (c-1) is a condensate of (c-1-2) at least one selected from phenol, m-cresol, p-cresol and xylenol with formaldehyde, and the hydrogen of the hydroxyl group thereof is The photosensitive substrate according to claim 4, which is a compound in which at least one of the atoms is substituted with a tert-butyloxycarbonylalkyl group. 8. The component (C) is a polymer having (c-2) at least 2 mol% of a (meth) acrylic acid derivative unit having an acid dissociable, dissolution inhibiting group, and having a weight average molecular weight of at least 2 mol%. The photosensitive substrate according to claim 1, wherein the photosensitive substrate has a range of 2,000 to 20,000. 9. The component (c-2) has (c-2-1) 50-70 mol% of a hydroxy (α-methyl) styrene unit and (c-2-2) an acid dissociable, dissolution inhibiting group ( Meta)
The photosensitive substrate according to claim 8, which is a copolymer comprising 30 to 50 mol% of acrylic acid derivative units. 10. The acid dissociable, dissolution inhibiting group is selected from a tertiary alkoxycarbonyl group, a tertiary alkoxycarbonylalkyl group, a tertiary alkyl group, a cyclic ether group, an alkoxyalkyl group and a 1-alkylcycloalkyl group. The photosensitive substrate according to any one of claims 1 to 6, which is at least one of the following. 11. The acid dissociable, dissolution inhibiting group includes a tert-butyloxycarbonyl group, a tert-butyloxycarbonylmethyl group, a tert-butyl group, a tetrahydropyranyl group, an ethoxyethyl group, a 1-methylcyclohexyl group, and a 1-methylcyclohexyl group. The photosensitive substrate according to claim 10, wherein the photosensitive substrate is at least one selected from an ethylcyclohexyl group. 12. The method according to claim 12, wherein the acid dissociable, dissolution inhibiting group is a tertiary alkyl group, a cyclic ether group, an alkoxyalkyl group,
At least one selected from an alkylcycloalkyl group
9. The photosensitive substrate according to claim 8, which is a seed. 13. An acid dissociable, dissolution inhibiting group comprising a tert-butyl group, a tetrahydropyranyl group, an ethoxyethyl group,
13. It is at least one selected from a -methylcyclohexyl group and a 1-ethylcyclohexyl group.
3. The photosensitive substrate according to item 1. 14. The positive resist composition according to claim 1, further comprising (D) an aliphatic lower amine in an amount of 0.01 to 1.0 part by weight based on 100 parts by weight of the component (B). Or the photosensitive substrate according to item 1. 15. The positive resist composition further comprises (E) an organic carboxylic acid or an oxo acid of phosphorus or a derivative thereof in an amount of 0.01 to 100 parts by weight of component (B).
The photosensitive substrate according to any one of claims 1 to 14, wherein the photosensitive substrate is contained in an amount of 1.0 part by weight. 16. The resist pattern according to claim 1, wherein the photosensitive substrate according to claim 1 is sequentially subjected to selective exposure by a KrF excimer laser, heating after exposure, and alkali development. Forming method. 17. The photosensitive substrate according to claim 1, wherein the resist layer has a thickness of 1000 to 58.
17. The method for forming a resist pattern according to claim 16, which has a thickness of 00 °. 18. The method according to claim 1, wherein the photosensitive substrate according to claim 1 is sequentially subjected to selective exposure with light having a wavelength of F ₂ (157 nm) or less, heating after exposure, and alkali development. Characteristic method of forming a resist pattern. 19. The photosensitive substrate according to claim 1, wherein the resist layer has a thickness of 500 to 100.
19. The method for forming a resist pattern according to claim 18, wherein the thickness is 0 [deg.]. 20. (A) a compound capable of generating an acid upon irradiation with radiation, (B) an alkali-soluble novolak resin, and (C) an acid having at least one acid dissociable, dissolution inhibiting group. In a positive resist composition comprising a compound capable of generating an organic carboxylic acid by dissociation of the dissolution inhibiting group by action, the component (C) has a weight average molecular weight of 100 to 1500, and at least one acid A positive resist composition comprising a bile acid ester having a dissociable, dissolution inhibiting group. 21. (A) a compound capable of generating an acid upon irradiation with radiation, (B) an alkali-soluble novolak resin, and (C) an acid having at least one acid-dissociable, dissolution-inhibiting group. In a positive resist composition comprising a compound capable of generating an organic carboxylic acid by dissociation of the dissolution inhibiting group by the action, the component (C) is used under the following conditions (c-1) and (c-1-1): A positive resist composition, wherein (C-1): a compound having a weight average molecular weight of 100 to 1500. (C-1-1): a compound in which at least one hydroxyl group or carboxyl group hydrogen atom of the compound represented by the following general formula (I) is substituted with an acid dissociable, dissolution inhibiting group. Embedded image [Wherein, R ^{1 to} R ⁴ each independently represent a hydrogen atom, a linear, branched or cyclic alkyl group having 6 or less carbon atoms, a lower alkoxy group, a hydroxyl group, a carboxyl group, or a carboxyl group-containing alkyl group. X is a single bond, —C (O) —, or —C (R ⁵ ) (R ⁶ ) —, R ⁵ is a hydrogen atom or a lower alkyl group, R ⁶ is a hydrogen atom, a lower An alkyl group, a carboxyl group, a carboxyl group-containing alkyl group or an aryl group represented by the following general formula (II) (R ¹ to R ¹ in the formula (II))
R ⁴ is the same as defined above), q is 0 or 1, and when q is 0, the group in parentheses is a hydrogen atom. ] 22. (A) a compound capable of generating an acid upon irradiation, (B) an alkali-soluble novolak resin, and (C) an acid having at least one acid-dissociable, dissolution-inhibiting group. In a positive resist composition comprising a compound capable of generating an organic carboxylic acid by dissociation of the dissolution inhibiting group by the action, the component (C) comprises the following (c-1 ′) and (c-1-2) A positive resist composition which satisfies conditions simultaneously. (C-1 ′): a compound having a weight average molecular weight of 100 to 1500, having 1 to 6 substituted or unsubstituted benzene nuclei, and having at least one acid dissociable, dissolution inhibiting group. . (C-1-2): a condensate of formaldehyde with at least one selected from phenol, m-cresol, p-cresol and xylenol, wherein at least one of the hydrogen atoms of the hydroxyl group is tert-butyloxycarbonylalkyl Is a compound substituted with a group. (A) a compound capable of generating an acid upon irradiation with radiation, (B) an alkali-soluble novolak resin, and (C) an acid having at least one acid-dissociable, dissolution-inhibiting group. In a positive resist composition comprising a compound capable of generating an organic carboxylic acid by dissociation of the dissolution inhibiting group by the action, the component (C) satisfies the following condition (c-2): -Type resist composition. (C-2): a polymer having at least 2 mol% or more of a (meth) acrylic acid derivative unit having an acid dissociable, dissolution inhibiting group, and having a weight average molecular weight of 2,000 to 20,
000. 24. The polymer according to (c-2),
(C-2-1) 50-70 mol% of hydroxy (α-methyl) styrene unit and (c-2-2) (meth) acrylic acid derivative unit 30-50 having an acid dissociable, dissolution inhibiting group
The positive resist composition according to claim 23, which is a copolymer consisting of mol%. 25. The acid dissociable, dissolution inhibiting group is selected from a tertiary alkoxycarbonyl group, a tertiary alkoxycarbonyloxyalkyl group, a tertiary alkyl group, a cyclic ether group, an alkoxyalkyl group, and a 1-alkylcycloalkyl group. The positive resist composition according to claim 20, which is at least one selected from the group consisting of: 26. The acid dissociable, dissolution inhibiting group includes a tert-butyloxycarbonyl group, a tert-butyloxycarbonylmethyl group, a tert-butyl group, a tetrahydropyranyl group, an ethoxyethyl group, a 1-methylcyclohexyl group, and a 1-methylcyclohexyl group. 26. The positive resist composition according to claim 25, which is at least one member selected from an ethylcyclohexyl group. 27. An acid dissociable, dissolution inhibiting group comprising a tertiary alkyl group, a cyclic ether group, an alkoxyalkyl group, and 1-
At least one selected from an alkylcycloalkyl group
24. The positive resist composition according to claim 23, which is a seed. 28. The acid dissociable, dissolution inhibiting group is a tert-butyl group, a tetrahydropyranyl group, an ethoxyethyl group,
28. It is at least one selected from a -methylcyclohexyl group and a 1-ethylcyclohexyl group.
4. The positive resist composition according to item 1. 29. The positive resist composition according to claim 20, further comprising (D) an aliphatic lower amine in an amount of 0.01 to 1.0 part by weight based on 100 parts by weight of the component (B). The positive resist composition according to claim 1. 30. The positive resist composition further comprises (E) an organic carboxylic acid or an oxo acid of phosphorus or a derivative thereof in an amount of from 0.01 to 100 parts by weight of component (B).
30. The positive resist composition according to any one of claims 20 to 29, comprising 1.0 part by weight.