JP2000098614A - Positive type photosensitive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a positive type photosensitive composition having high sensitivity and resolving power to far UV, particularly ArF excimer laser light and also having suitability to a standard developer by incorporating a specified polymer. SOLUTION: The photosensitive composition contains a polymer which has structural units of formula I and/or formula II and is decomposed by the action of an acid, a compound which generates the acid when irradiated with active light or radiation and a solvent. In the formulae I and II, R1 and R2 are each H, hydroxyl, halogen, alkyl, alkoxy, an alkali-soluble group or an acid decomposable group, the alkali-soluble group is preferably a group having carboxyl and the acid decomposable group is, e.g. a group of the formula -(O-R)n-COOR3 (where R is preferably 1-4C alkylene and R3 may be tertiary alkyl such as t-butyl or t-amyl).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive photosensitive composition used in a process for producing semiconductors such as ICs, a circuit substrate for liquid crystals and thermal heads, and other photofabrication processes. It is. More specifically, the present invention relates to a positive photosensitive composition suitably used for fine processing of a semiconductor device using light energy rays having a short wavelength such as far ultraviolet rays, X-rays, and electron beams, and particularly relates to a semiconductor device using an ArF excimer laser. The present invention relates to a positive photosensitive composition that can be suitably used for microfabrication.

[0002]

2. Description of the Related Art In recent years, high integration of semiconductor integrated circuits has progressed, and LSIs and VLSIs have been put to practical use, and the minimum pattern width of integrated circuits has reached a sub-half micron region, and further miniaturization has been progressing. Therefore, the demand for photolithography technology for forming a fine pattern is becoming more and more severe. As one of means for miniaturizing a pattern, it is known to shorten the wavelength of exposure light used when forming a resist pattern.

[0003] For example, DR with an integration degree of up to 64 Mbits
To date, the manufacture of AM has been based on the i-line (365
nm) has been used as a light source. 256 Mbit D
In the mass production process of RAM, a KrF excimer laser (248 nm) has been put to practical use as an exposure light source instead of i-line, and a light source with a shorter wavelength has been studied for the purpose of manufacturing a DRAM having an integration degree of 1 Gbit or more. I have. Examples of such a short wavelength light source include an ArF excimer laser (193 nm) and an F ₂ excimer laser (157 n).
m), the use of X-rays and electron beams is considered to be effective (Takumi Ueno et al., "Short Wavelength Photoresist Material-ULSI
Micromachining for ”, Bunshin Publishing, 1988).

In particular, an ArF excimer laser is positioned as a next-generation exposure technology, and development of a resist for ArF excimer laser exposure having high sensitivity, high resolution, and excellent dry etching resistance has been desired. Conventional i-line and K
As a resist material for rF excimer laser exposure,
To obtain high dry etching resistance, resists containing aromatic polymers are widely used, for example,
A novolak resin-based resist or a polyvinyl phenol-based chemically amplified resist is known. However, since the aromatic ring introduced for the purpose of imparting dry etching resistance hardly transmits light in the wavelength range of ArF excimer laser light, it is difficult to expose even the bottom of the resist film. Did not provide a good pattern in cross section.

It is known that one of the solutions to the problem of resist transparency is to use an aliphatic polymer containing no aromatic ring, for example, polymethyl methacrylate (J. Vac. Sci. Technol., B9, 3357 (1991)). However, such a polymer cannot be practically used because sufficient dry etching resistance cannot be expected. As described above, in developing a resist material for ArF excimer laser exposure, it is the greatest challenge to achieve both improved transparency and high dry etching resistance. Therefore, the fact that a resist containing an alicyclic hydrocarbon group instead of an aromatic ring shows the same resistance to dry etching as an aromatic group and has a small absorption at 193 nm, Proc. SPIE,
1672, 66 (1992), and in recent years the use of this polymer has been energetically studied.

[0006] Originally, attempts to apply a polymer containing an alicyclic hydrocarbon group to a resist have been made for a long time. For example, Japanese Patent Application Laid-Open Nos. 60-195542, 1-217453 and 2-59751 have been proposed. Discloses a norbornene-based polymer, and JP-A-2-46045 discloses various alkali-soluble resins having a cyclic aliphatic hydrocarbon skeleton and a maleic anhydride unit. Further, JP-A-5-80515 discloses a copolymer of norbornene and an acrylic acid ester protected with an acid-decomposable group, and is disclosed in JP-A-4-39665, JP-A-5-265212, and JP-A-5-80515. And JP-A-7-234511
Discloses a copolymer having an adamantane skeleton in the side chain, and JP-A-7-252324 and JP-A-9-221526 disclose an aliphatic group having 7 to 12 carbon atoms having a bridged cyclic hydrocarbon group. cyclic hydrocarbon group, the compound linked to the side chain of the polymer, e.g., tricyclo [5,2,1,0 ^2,6] decane methylene group, a tricyclo [5,2,1,0 ^2,6] decanediyl Group, norbornanediyl group, norbornanedimethyl group,
An adamantanediyl group is disclosed, and JP-A-7-199467 discloses a compound in which a tricyclodecanyl group, a dicyclopentenyl group, a dicyclopentenyloxyethyl group, a norbornyl group, and a cyclohexyl group are linked to a side chain of a polymer, respectively. Have been.

Further, Japanese Patent Application Laid-Open No. 9-325498 discloses a polymer having a cyclohexane and isobornyl skeleton in the main chain, and further disclosed in JP-A-9-230595, JP-A-9-244247,
JP-A-10-10739, WO97-33198, EP794458, EP789278 disclose a polymer in which various cyclic olefins such as dicycloolefin are introduced into the main chain, JP-A-8-82925,
JP-A-9-230597 discloses that a compound having a menthyl group or a menthyl derivative group among terpenoid skeletons is preferable. However, as an adverse effect of introducing an alicyclic hydrocarbon site, the system becomes extremely hydrophobic,
Conventionally, tetramethylammonium hydroxide (hereinafter referred to as TMAH) has been widely used as a developing solution for resist.
There are phenomena such as difficulty in developing with an aqueous solution and peeling of the resist from the substrate during development.

In order to cope with such hydrophobicity of the resist, studies have been made to mix an organic solvent such as isopropyl alcohol with a developing solution. Although some results have been obtained, there is concern about swelling of the resist film and the process becomes complicated. However, the problem has not always been solved. In the approach of improving the resist itself, many measures have been taken to supplement hydrophobic alicyclic hydrocarbon sites by introducing a hydrophilic group.

In general, a measure has been taken in which a monomer having a carboxylic acid moiety such as acrylic acid or methacrylic acid is copolymerized with a monomer having an alicyclic hydrocarbon group. In addition, although there is a tendency to improve the substrate adhesion, there are many problems such as deterioration of dry etching resistance and further increase in resist film loss, and the above-mentioned problems have not been solved. Furthermore, in JP-A-7-234511, a monomer having a hydroxyl group or a cyano group in the molecule instead of a carboxylic acid group such as HEMA or acrylonitrile is referred to as a monomer having an alicyclic hydrocarbon group. The aim was to solve the developability by copolymerization, but the solution was not sufficiently satisfactory.

Recently, J. Photopolym. Sci., Tec.
h., Vol. 9, 509 (1996) and J. Photopolym. Sci., Tech.,
As described in Vol. 10, 545 (1997), improvement of substrate adhesion has been studied by focusing on a lactone structure such as mevalonic lactone. However, in order to ensure developability, it requires an overcoat layer that complicates the process,
The developability is insufficient, and the substrate adhesion is also insufficient. In Japanese Patent Application Laid-Open No. 8-289626, a monomer having a carboxylic acid group and an alicyclic hydrocarbon moiety in a molecule at the same time is studied, and dry etching resistance, developability, and substrate adhesion are improved. Nevertheless, problems such as lack of substrate adhesion and suitability for a standard developer due to extremely high solubility of the developer have been encountered.

Similarly, Japanese Patent Application Laid-Open No. 9-325498 discusses a polymer having a cyclohexane skeleton or isobornyl skeleton in which an acidic substituent such as a carboxylic acid group or a sulfonic acid group is introduced into a side chain in a main chain. Although the properties have been improved, the adhesion to the substrate has not yet reached a satisfactory level. Also, J. Photopolym. Sci., Tech., Vo
As described in l. 10,561 (1997), improvements have been made by copolymerizing alicyclic hydrocarbon monomers having alcoholic hydroxyl groups, but they have not yet reached a satisfactory level. Absent.

Furthermore, a report has been made on introducing a hydroxyl group into the norbornene polymer main chain from the viewpoint of imparting substrate adhesion (J. Photop.
olym. Sci., Tech., Vol. 10, 529 (1997), J. Photopoly.
m. Sci., Tech., Vol. 10, 521 (1997)), but satisfactory results have not been obtained in both developability and substrate adhesion. As described above, the photosensitivity has high transparency to deep ultraviolet rays of ArF excimer laser light, has high dry etching resistance, is uniformly dissolved in an alkali developing solution, and has excellent adhesion to a substrate. The composition has not yet been obtained.

[0013]

SUMMARY OF THE INVENTION The object of the present invention has been made in view of the above-mentioned problems, and has been made in consideration of the following problems.
In particular, it has high sensitivity and resolution to ArF excimer laser light, has excellent resist profile, and is suitable for a standard developer (2.38% TMAH aqueous solution) capable of forming a resist pattern that does not peel off from the substrate. An object of the present invention is to provide a positive photosensitive composition.

[0014]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on the constituent materials of a positive type chemically amplified resist composition, and have found that a combination of a polymer containing a specific structure as a structural unit and a photoacid generator. The inventors have found that the object is achieved, and have reached the present invention. That is, the present invention is achieved by a method having the following configuration. (1) (a) a polymer having a structural unit represented by the following general formula (I) or / and (II) and decomposing by the action of an acid; (b) an acid by irradiation with actinic rays or radiation A positive photosensitive composition comprising a compound to be generated and (c) a solvent.

Formula (I)

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Formula (II)

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(In the formulas (I) and (II), R ₁ and R ₂ are
Each independently represents a hydrogen atom, a hydroxyl group, a halogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, an alkali-soluble group or a group which is decomposed by the action of an acid. (2) The method according to (1), further comprising a low-molecular acid-decomposable dissolution inhibiting compound having a molecular weight of 1,000 or less, which has a group decomposable by the action of an acid and has an alkali solubility increased by the action of an acid. The positive photosensitive composition as described in the above.

[0018]

Embodiments of the present invention will be described below in detail. R _{1 of the} above general formulas (I) and (II)
And a halogen atom for R ₂ is preferably fluorine, chlorine, bromine, or iodine, and among them, a chlorine atom is more preferable. As the alkyl group for R ₁ and R ₂ ,
A linear, branched or cyclic alkyl group is exemplified.
Here, the linear or branched alkyl group is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, more preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, or an n-butyl group. Group, isobutyl group,
They are a sec-butyl group and a t-butyl group. Examples of the cyclic alkyl group include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, an adamantyl group, a 2-methyl-2-adamantyl group, a norbornyl group, a boronyl group, an isobornyl group, a tricyclodecanyl group, a dicyclopentenyl group, and a mentyl group. , An isomenthyl group, a neomenthyl group, a tetracyclododecanyl group and the like. As the alkoxy group, a linear or branched alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, and a heptyloxy group is preferable. The alkyl group and the alkoxy group are
Further, it may have a substituent. Examples of the further substituent include a halogen atom, a hydroxyl group, a carboxyl group, a carbonyl group, an amino group, a nitrile group, an ester group, and a nitro group.

Examples of the alkali-soluble group include a carboxyl group, a phenolic hydroxyl group, an active methylene group, a sulfonamide group and a group having these groups, and a group having a carboxyl group is preferred.

An acid-decomposable group (also referred to as an acid-labile group) is a group that decomposes under the action of an acid. Specific examples of the acid-decomposable group include groups represented by the following general formula (III) or general formula (IV). Formula (III) - (O-R ) n-COOR 3 formula (IV) -O-C (= O) - (Ro) m-COOR 3

Here, R ₃ is a t-butyl group, t
A tertiary alkyl group such as an amyl group, an isobornyl group, 1-
1-alkoxyethyl groups such as ethoxyethyl group, 1-butoxyethyl group, 1-isobutoxyethyl group, 1-cyclohexyloxyethyl group, 1-methoxymethyl group, 1
-An alkoxymethyl group such as an ethoxymethyl group, a tetrahydrobiranyl group, a tetrahydrofuranyl group and the like. R is preferably an alkylene group having 1 to 4 carbon atoms, more preferably methylene. Ro represents a methylene group. n represents 0 or 1, and m represents 1 to 6.
Represents an integer.

The acid-decomposable group as described above is used in the polymer of the present invention in the general formula (I) and / or the general formula (II).
Or may be contained in another copolymerization component. Examples of the other copolymer component include a monomer having a copolymerizable vinyl polymerizable group. In the present invention, the acid-decomposable group is represented by the general formula (I) and / or the general formula (I)
It is preferably present in I). More specifically, the polymer in the present invention is a polymer having the following structure, but the present invention is not limited thereto.

[0023]

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[0024]

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[0025]

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The polymer having the structural unit represented by the general formula (I) in the present invention can be obtained, for example, by photopolymerizing a corresponding 1,5-hexadiene derivative in a solvent. The polymerization reaction carried out in a solvent is carried out in an organic solvent such as toluene using Irgacure 184 (Ciba-
UV irradiation in the presence of a photopolymerization initiator such as Geigy Corporation). Similarly, the polymer having a structural unit represented by the general formula (II) in the present invention is:
It can be synthesized from the corresponding 1,6-heptadiene derivative. For example, Alan William Hall et al.
mol. Rapid Commun. 17, 417-425 (1996) and the like. When an acid-decomposable group is introduced into the raw material monomer in advance, after reacting for a predetermined time, the resulting polymer and unreacted monomer components, solvents, etc. should be purified by vacuum distillation, reprecipitation method, etc. Is preferred. Specific examples of the structures of the 1,5-hexadiene derivative and the 1,6-heptadiene derivative as monomers are shown below.

[0027]

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[0028]

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The polymer thus obtained is measured for its retention time by gel permeation chromatography equipped with a refractive index detector in comparison with polystyrene having a known molecular weight, and the weight average molecular weight is determined. The polymer used in the composition of the present invention preferably has a weight average molecular weight in the range of 1500 to 100,000, more preferably 2,000.
To 70,000, particularly preferably in the range of 3,000 to 50,000. Weight average molecular weight 1,5
If it is less than 00, the dry etching resistance, heat resistance, and adhesion to the substrate tend to be insufficient, and if it exceeds 100,000, the resist sensitivity tends to decrease, which is not preferable. The degree of dispersion (Mw / Mn) is preferably 1.
0 to 6.0, more preferably 1.0 to 4.0, and the smaller the value, the better the heat resistance and image performance (resist profile, defocus latitude, etc.).

A polymer in which a cyclohexane skeleton having a carboxylic acid group is introduced into the main chain and a cycloaliphatic hydrocarbon skeleton is bonded by a single bond is disclosed in JP-A-9-325498. JP-A-9-244247 and EP-0789278 disclose resins obtained by subjecting a norbornene-substituted product to ring-opening polymerization and then performing a hydrogenation reaction.

However, these resins have improved developability, but still have insufficient adhesion to a substrate. On the other hand, it is not clear why the composition of the present invention is specifically excellent in developability and adhesion, but the polymer used in the composition of the present invention has cyclopentane having a specific structure in the main chain. It is thought that it was expressed due to the characteristic caused by having a basic structural unit called a ring.

In order to improve the performance of the resin of the present invention,
Another polymerizable monomer may be further copolymerized as long as the transparency of 220 nm or less and the dry etching resistance of the resin are not significantly impaired. Examples of the copolymerizable monomer that can be used include the following. For example, an addition-polymerizable polymer selected from acrylic acid, methacrylic acid, acrylic esters, acrylamides, methacrylic esters, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, styrenes, crotonic esters, and the like. There are a compound having one saturated bond, an acid anhydride such as maleic anhydride, maleimide, acrylonitrile, methacrylonitrile, and the like. Others
Generally, any addition-polymerizable unsaturated compound that can be copolymerized can be used.

Specific examples of copolymerizable monomers such as acrylates and methacrylates include alkyl acrylates having 1 to 8 carbon atoms, methyl acrylate, ethyl acrylate, propyl acrylate, and acrylic acid. t-butyl, amyl acrylate, cyclohexyl acrylate, 2-hydroxyethyl acrylate,
Phenyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, t-butyl methacrylate, amyl methacrylate, cyclohexyl methacrylate, adamantyl methacrylate, 2-hydroxyethyl methacrylate, phenyl methacrylate, naphthyl methacrylate, acrylic acid Tricyclodecanyl, tricyclodecyl acrylate, tetrahydropyranyl methacrylate, ethoxyethyl methacrylate, butoxyethyl methacrylate, methoxypropyl methacrylate, cyclohexylethyl methacrylate, adamantyl oxyethoxyethyl methacrylate, adamantyl carbonyloxyethoxy methacrylate Ethyl, 1-paramenthyl methacrylate, 3-oxocyclohexyl methacrylate, menthyl methacrylate and the like

Specific examples of acrylamide and methacrylamide include N, N-dimethylacrylamide, N, N-diethylacrylamide, N-methyl-
N-phenylacrylamide, N-hydroxyethyl-
N-methylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylmethacrylamide, N-methyl-N-phenylmethacrylamide, N-hydroxyethyl-N-ethylmethacrylamide, N-cyclohexylmaleimide and the like can be mentioned. .

Specific examples of the allyl compound include allyl esters such as allyl acetate, allyl acetoacetate, allyl lactate and allyl benzoate. Specific examples of vinyl ethers include alkyl vinyl ethers such as ethylhexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, and hydroxyethyl vinyl ether; vinyl aryl ethers such as vinyl phenyl ether and vinyl naphthyl ether; vinyl butyrate and vinyl isobutyrate. , Vinyl valate, vinyl methoxy acetate, vinyl lactate, vinyl benzoate, vinyl salicylate, vinyl naphthoate and the like.

Specific examples of styrenes include styrene,
Examples include p-hydroxystyrene, carboxystyrene, methylstyrene, methoxystyrene, and acetoxystyrene. Specific examples of crotonic esters include butyl crotonate and hexyl crotonate. Other examples of the copolymerizable addition-polymerizable unsaturated compound include norbornene, 1,5-dimethyl-1,5-
Examples include alicyclic hydrocarbon compounds such as cyclooctadiene, 5,6-dihydrodicyclopentadiene, and 1,5-octadiene, and derivatives thereof.

In the polymer of the present invention, the content of the repeating units represented by the general formulas (I) and (II) is preferably 10 mol% or more, more preferably 20 mol%, of the repeating units of all the monomers. Mol% or more, more preferably 30 mol% or more. In the polymer of the present invention, the content of the repeating unit having an acid-decomposable group is preferably 5 mol% or more, more preferably 10 mol% or more, and still more preferably 15 mol% or more based on the repeating units of all the monomers. It is. In the polymer of the present invention, the content of the other copolymer component is preferably 50 mol% or less, more preferably 40 mol% or less, and still more preferably 30 mol% or less, based on the repeating units of all the monomers.

In the present invention, the amount of the above polymer in the photosensitive composition (excluding the solvent) is 50 to 99.7% by weight, preferably 70 to 99% by weight, based on the total solid content.

Next, the photoacid generator in the positive photosensitive composition of the present invention will be described. Used in the present invention,
Examples of compounds that decompose upon irradiation with actinic rays or radiation to generate an acid include a photoinitiator for photocationic polymerization, a photoinitiator for photoradical polymerization, a photodecolorant for dyes, a photochromic agent, or an ultraviolet ray. , A micro-photoresist that generates acid by far ultraviolet rays, KrF excimer laser light, ArF excimer laser light, electron beam, X-ray, molecular beam or ion beam, and appropriately selects a known photoacid generator and a mixture thereof. Can be used.

Of these, preferred for use in the present invention are photoacid generators which generate an acid with light having a wavelength of 220 nm or less, and the mixture of the polymer with the above-mentioned polymer of the present invention can be sufficiently used in an organic solvent. Any photoacid generator may be used as long as it dissolves. Further, they may be used alone or as a mixture of two or more kinds, or may be used in combination with an appropriate sensitizer. Examples of usable photoacid generators include, for example, J.
Org. Chem. Vol. 43, N0.15, 3055 (1978). Triphenylsulfonium salt derivative and Japanese Patent Application No. 9-279071.
Other onium salts described in (1) (sulfonium salts, iodonium salts, phosphonium salts, diazonium salts, ammonium salts) can also be used.

Specific examples of the onium salts include diphenyliodonium triflate, diphenyliodonium pyrene sulfonate, diphenyliodonium, dodecylbenzenesulfonate, triphenylsulfonium triflate, triphenylsulfonium hexafluoroantimonate, diphenyliodonium hexafluoroantimonate, and triphenyliodonium hexafluoroantimonate. Examples include phenylsulfonium naphthalene sulfonate, triphenylsulfonium camphorsulfonium, (4-methoxyphenyl) phenyliodonium trifluoromethanesulfonate, and bis (t-butylphenyl) iodonium trifluoromethanesulfonate.

Further, JP-A-3-103854, JP-A-3-103856
Diazodisulfones and diazoketosulfones described in JP-A-4-210960, JP-A-64-18143, JP-A-2-24
Iminosulfonates described in 5756, JP-A-2-71
Disulfones described in No. 270 can also be suitably used. Further, USP 3849137, JP-A-63-26653, JP-A-62
-69263, JP-A-63-146038, JP-A-63-163452,
The compounds described in JP-A-62-153853 and JP-A-63-146029, in which a group capable of generating an acid by light is introduced into the main chain or side chain of the polymer, can also be used.

Further, Japanese Patent Application Laid-Open Nos. Hei 7-25846 and Hei 7-846
No. 28237, aliphatic alkylsulfonium salts having a 2-oxocyclohexyl group described in JP-A-7-92675 and JP-A-8-27120, and N-hydroxysuccinimide sulfonates, and further, J. Photopolym.Sci., Te
ch., Vol. 7, No. 3, 423 (1994), etc. can also be suitably used, and these photoacid generators can be suitably used alone or in combination of two or more. it can.

The amount of the compound which decomposes upon irradiation with actinic rays or radiation to generate an acid, which is variously mentioned above, is as follows:
It is usually in the range of 0.001 to 40% by weight, preferably 0.01 to 20% by weight, more preferably 0.1 to 5% by weight, based on the total weight of the photosensitive composition (excluding the coating solvent).
% By weight. 0.001 of photoacid generator added
If the amount is less than% by weight, the sensitivity decreases, and conversely,
If the addition amount exceeds 40% by weight, the light absorption of the resist becomes too high, and the profile is deteriorated and the process (especially baking) margin is unfavorably reduced.

The positive photosensitive composition of the present invention has a low molecular weight acid-decomposable dissolution inhibiting compound having a molecular weight of 1,000 or less, which has a group decomposable by the action of an acid and whose alkali solubility is increased by the action of an acid. Is preferably contained. In order to increase the dissolution rate ratio with respect to the alkali in the unexposed area and the exposed area and to obtain a high resolution, it is effective to add a compound which increases the alkali solubility by the action of the acid. The low-molecular acid-decomposable dissolution inhibiting compound used in the present invention includes:
Those that do not decrease the transmittance for light having a wavelength of 220 nm or less, dry etching resistance, and heat resistance are preferable.
These compounds include, for example, Proc. SPIE, 2724, 355
(1996) and JP-A-8-15865, US5310619, US5372912
Of cholic acid derivatives containing acid-decomposable groups, dehydrocholic acid derivatives, deoxycholic acid derivatives, lithocholic acid derivatives, ursocholic acid derivatives, and abietic acid derivatives protected with acid-decomposable groups as described in Such alicyclic compounds can also be preferably used. Further, low-molecular acid-decomposable dissolution inhibiting compounds described in JP-A-6-51519 can also be used in an addition range of a level that does not deteriorate the transmittance at 220 nm.
-Naphthoquinone diazide compounds can also be used.

When an acid-decomposable dissolution-inhibiting compound is used in the photosensitive composition of the present invention, the amount thereof is usually 1% based on the total weight of the photosensitive composition (excluding the coating solvent).
It is used in the range of -50% by weight, preferably in the range of 3-40% by weight, more preferably in the range of 5-30% by weight.

The positive photosensitive composition of the present invention may contain, if necessary, an organic basic compound, a compound for promoting the solubility in a developing solution, and the like. Preferred organic basic compounds that can be used in the present invention include compounds that are more basic than phenol,
Among them, a nitrogen-containing basic compound is more preferable. The organic basic compound is mainly added for the purpose of improving the stability over time and the adhesion properties of the acid scavenger and the resist. For example,
63-149640, JP-A-5-249662, JP-A-6-242605,
JP-A-6-242606, JP-A-6-266100, JP-A-7-120929
JP-A-9-274312 and JP-A-7-508840 include these organic basic compounds, and those which do not vaporize or sublime are suitably used.

Among these organic basic compounds, 1,5-
Diazabicyclo [4,3,0] -5-nonene, 1,8-
Diazabicyclo [5,4,0] -7-undecene, 1,
4-diazabicyclo [2,2,2] octane, 4-dimethylaminopyridine, 1-naphthylamine, N-methylformamide, piperidine, hexamethylenetetramine, imidazoles are particularly preferably used. Also, JP-A-6-242606, JP-A-6-242605, basic ammonium salts and sulfonium salts described in JP-A-8-110635, etc.
Alternatively, an internal salt such as betaine can be used.

Of these, pyridinium p-toluenesulfonate, 2,4,6-trimethylpyridinium p-toluenesulfonate, tetramethylammonium p-toluenesulfonate, tetrabutylammonium lactate and the like are particularly preferably used. These nitrogen-containing basic compounds are used alone or in combination of two or more. The amount of the nitrogen-containing basic compound used is usually 0.1 to 100 parts by weight of the photosensitive composition (excluding the solvent).
001 to 10 parts by weight, preferably 0.01 to 5 parts by weight. If the amount is less than 0.001 part by weight, the effect of adding the nitrogen-containing basic compound cannot be obtained. On the other hand, if it exceeds 10 parts by weight, the sensitivity tends to decrease and the developability of the unexposed part tends to be remarkably deteriorated.

Examples of the compound capable of accelerating dissolution in a developer which can be used in the present invention include compounds having two or more phenolic hydroxyl groups described in JP-A-3-206458,
Naphthols such as naphthol, or JP-A-3-1793
No. 55, JP-A-5-181279, JP-A-9-6001, JP-A-9-27
No. 4,318, US Pat. No. 5,374,500, compounds having one or more carboxyl groups described in DE4214363, carboxylic anhydrides, low molecular weight compounds having a molecular weight of 1,000 or less such as sulfonamide compounds and sulfonylimide compounds described in Japanese Patent Application No. 9-279071. Can be mentioned. Among these, dissolution-promoting compounds that do not deteriorate the permeability to light having a wavelength of 220 nm are preferable, and for example, steroids, norsteroids, and terpenoids are preferable, and especially adamantanecarboxylic acid, cholic acid, norcholanic acid, and abietin Acids and agatenedicarboxylic acids are preferred.

The positive photosensitive composition of the present invention may further contain, if necessary, an antihalation agent, a plasticizer, a surfactant, a photosensitizer, an adhesion aid, a crosslinking agent, a photobase generator and the like. can do. As a suitable antihalation agent, a compound that efficiently absorbs irradiation radiation is preferable, and fluorene, 9-fluorenone, substituted benzenes such as benzophenone, anthracene, and anthracene-9-
Examples thereof include polycyclic aromatic compounds such as methanol, anthracene-9-carboxyethyl, phenanthrene, perylene, and azylene. Of these, polycyclic aromatic compounds are particularly preferable.

These antihalation agents exhibit the effect of improving the standing wave by reducing the reflected light from the substrate and reducing the influence of multiple reflection in the resist film. In order to improve the acid generation rate by exposure, a photosensitizer as described below can be added. Suitable photosensitizers include, specifically, benzophenone, p-p'tetramethyldiaminobenzophenone, 2-chlorothioxanthone, anthrone, 9-ethoxyanthracene, pyrene, phenothiazine, benzyl, benzoflavin, acetophenone, phenanthrene, benzoquinone , Anthraquinone, 1,2-naphthoquinone and the like, but are not limited thereto.
These photosensitizers can also be used as the antihalation agent.

To the photosensitive composition of the present invention, the following surfactants can be added for the purpose of improving coatability and improving developability. Examples of such surfactants include, for example, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, polyethylene glycol dilaurate, polyethylene glycol distearate, and polyoxyethylene nonyl phenyl ether. Nonionic surfactants such as oxyethylene sorbitan monostearate and sorbitan monolaurate; F-Top EF301 and EF303 (manufactured by Shin-Akita Chemical Co., Ltd.); Florad FC43
0,431 (manufactured by Sumitomo 3M Limited), Mega Fuck F171, F
173, F176, F177P (Dai Nippon Ink Co., Ltd.), Surflon
S-382, SC101,102,103,104,105,106 (made by Asahi Glass Co., Ltd.)
And other fluorosurfactants, polysiloxane polymer KP-3
41 (manufactured by Shin-Etsu Chemical Co., Ltd.).

The amount of these surfactants is usually 2 parts by weight or less, preferably 1 part by weight or less, per 100 parts by weight of the solids in the composition of the present invention. These surfactants may be used alone, or may be added in plural combinations. The positive photosensitive composition of the present invention may further contain a plasticizer, an adhesion aid, a crosslinking agent, a photobase generator, an antifoaming agent, and the like, if necessary.

After dissolving the photosensitive composition of the present invention in a solvent (c) capable of dissolving each of the above components, usually,
For example, it is prepared as a solution by filtering with a filter having a pore size of about 0.05 μm to 0.2 μm. Examples of the solvent (c) used herein include ethylene glycol monoethyl ether acetate, cyclohexanone, 2-heptanone, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether propionate, and propylene glycol monoethyl ether. Acetate, methyl 3-methoxypropionate, 3-
Ethyl ethoxypropionate, methyl β-methoxyisobutyrate, ethyl butyrate, propyl butyrate, methyl isobutyl ketone, ethyl acetate, isoamyl acetate, ethyl lactate, toluene, xylene, cyclohexyl acetate, diacetone alcohol, N-methylpyrrolidone, N, N- Dimethylformamide, γ-butyrolactone, N, N-ditylacetamide and the like can be mentioned.

These solvents are used alone or as a mixture. In addition, the selection of these solvents is important because it affects solubility in the composition, coatability to a substrate, storage stability, and the like, and water contained in the solvent also affects these performances, and is possible. It is more preferable that the number is as small as possible. Further, the photosensitive composition of the present invention, when mixed with metal impurities such as metals and impurity components such as chlor ions,
When manufacturing a semiconductor device, an operation failure, a defect, and a decrease in yield occur, which is not preferable. For this reason, it is preferable to reduce the mixed concentration of these impurity components to 100 ppb or less.

The photosensitive composition prepared by satisfying the above-mentioned various conditions is coated on a substrate by a suitable coating means such as a spinner, a coater or the like, prebaked (pre-exposure heating), and passed through a predetermined mask to a wavelength of 220 nm or less. A good resist pattern can be obtained by exposing with the above exposure light, performing PEB (post-exposure bake), and developing. The substrate used here may be a substrate usually used in a semiconductor device or other manufacturing apparatus, and examples thereof include a silicon substrate, a glass substrate, and a non-magnetic ceramic substrate.

Further, if necessary, additional layers such as a silicon oxide layer, a metal layer for wiring,
An interlayer insulating film, a magnetic film, an antireflection film layer and the like may be present, and various wirings and circuits may be formed. Furthermore, these substrates may be subjected to a hydrophobic treatment according to a conventional method in order to enhance the adhesion of the resist film. Suitable hydrophobizing agents include, for example, 1,1,
1,3,3,3-hexamethyldisilazane (HMDS)
And the like.

The thickness of the resist applied on the substrate is preferably in the range of about 0.1 μm to 10 μm. In the case of ArF exposure, the thickness is preferably 0.1 μm to 1.5 μm. The resist film applied on the substrate is preferably pre-baked at a temperature of about 60 to 160 ° C. for about 30 to 300 seconds. If the pre-baking temperature is low and the time is short, the amount of residual solvent in the resist film becomes relatively large, and adverse effects such as deterioration of adhesion are caused, which is not preferable. On the other hand, if the prebaking temperature is high and the time is long, adverse effects such as decomposition of components such as the binder and the photoacid generator of the photosensitive composition occur, which is not preferable.

[0060] As apparatus for exposing a resist film after prebaking, a commercially available ultraviolet exposure apparatus, X-ray exposure apparatus, an electron beam exposure apparatus, KrF excimer exposure apparatus, ArF excimer exposure system, F ₂ excimer exposure device and the like are used Particularly, in the present invention, an apparatus using an ArF excimer laser as an exposure light source is preferable. The post-exposure bake is for the purpose of causing the elimination of the protecting group catalyzed by an acid or the purpose of eliminating the standing wave,
This is performed for the purpose of diffusing an acid generator or the like into the film. This post-exposure bake can be performed in the same manner as the previous pre-bake. For example, the baking temperature is about 60 to 160
° C, preferably about 90-150 ° C.

As the developer for the photosensitive composition of the present invention,
Sodium hydroxide, potassium hydroxide, sodium carbonate,
Inorganic alkalis such as sodium silicate and aqueous ammonia,
Primary amines such as ethylamine and n-propylamine;
Secondary amines such as diethylamine and di-n-butylamine; and tertiary amines such as triethylamine and methyldiethylamine.
Amines, alcoholamines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), trimethylhydroxymethylammonium hydroxide, triethylhydroxymethylammonium hydroxide, trimethylhydroxyethyl Quaternary ammonium salts such as ammonium hydroxide, pyrrole, piperidine, 1,8-diazabicyclo- [5,
4,0] -7-undecene, 1,5-diazabicyclo-
An aqueous alkaline solution such as a cyclic amine such as [4,3,0] -5-nonane can be used.

Further, an appropriate amount of a hydrophilic organic solvent such as alcohols or ketones, a nonionic or anionic surfactant, a cationic surfactant or an antifoaming agent may be added to the alkaline aqueous solution. Can be used. These additives not only improve the performance of the resist but also enhance the adhesion to the substrate, reduce the amount of the developing solution used, and reduce defects caused by bubbles during development. Play.

[0063]

The present invention will be described in more detail with reference to examples including synthesis examples, but the present invention is not limited thereto. [Synthesis Example 1] 10 g of the above monomer (b-1) was added to toluene, 0.2 g of Irgacure184 was added thereto, and the mixture was stirred under irradiation with a mercury lamp for 7 hours to carry out polymerization. Residual monomers were separated from the obtained polymer solution by a reprecipitation method to obtain a polymer powder. The molecular weight of the polymer obtained by vacuum drying was 7,300 in weight average molecular weight. (Polymer A-1)

[0064]

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[Synthesis Example 2] The above-mentioned monomer (b-2)
A polymerization reaction was carried out in the same manner as in Synthesis Example 1 using 10 g. After purification by reprecipitation, a powder polymer was obtained. The molecular weight of the polymer obtained by vacuum drying was 8,700 in weight average molecular weight. (Polymer A-2)

[0066]

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[Synthesis Example 3] The above-mentioned monomer (b-6)
After polymerizing 10 g and purifying by reprecipitation in the same manner as in Synthesis Example 1, a powder polymer was obtained. The molecular weight of the polymer obtained by vacuum drying was 6,200 in weight average molecular weight.
(Polymer A-7)

[0068]

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[Synthesis Example 4] The above monomer (b-1)
0) After polymerizing 10 g and purifying by reprecipitation in the same manner as in Synthesis Example 1, a powder polymer was obtained. The molecular weight of the polymer obtained by vacuum drying was 7,900 as a weight average molecular weight. (Polymer A-13)

[0070]

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[Synthesis Example 5] Synthesis of acid-decomposable low molecular weight compound a A mixture of 12.27 g (0.03 mol) of cholic acid and 12 ml of thionyl chloride was refluxed for 1 hour. Excess thionyl chloride is removed, the solid obtained is dissolved in 15 ml of tetrahydrofuran, 4 g (0.035 mol) of potassium tert-butoxide are slowly added, the reaction mixture is refluxed for 6 hours, cooled and then poured into water. did. The resulting solid was collected by filtration, washed with water and dried under reduced pressure.
The purified product was recrystallized from n-hexane to obtain tert-butyl cholate (the following formula) in a yield of 74%.

[0072]

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Synthesis Example 6 Synthesis of Polymer C (Comparative Example) A polymer obtained by hydrogenating a ring-opened polymer of a norbornene derivative described in the fourth example disclosed in JP-A-9-244247 was converted to E.
It was synthesized according to the method described in PO789278.

[Image Evaluation] The photosensitive compositions of the present invention of Examples 1 to 7 having the formulations shown in Table 1 below were filtered through a 0.1 μm Teflon filter. The filtrate was uniformly coated on a hexamethyldisilazane-treated silicon substrate using a spinner coater, and this was heated and dried on a hot plate at 120 ° C. for 90 seconds to form a 0.57 μm resist film. . The structural formula of the photoacid generator contained in the composition is shown below.

[0075]

[Table 1] Solvent S-1: propylene glycol monomethyl ether acetate

[0076]

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The resist film is passed through a mask and
It was exposed to rF excimer laser light, and immediately after exposure, it was heated on a hot plate at 110 ° C. for 90 seconds, and then developed with a 2.38% aqueous tetramethylammonium hydroxide solution at 23 ° C. for 60 seconds. 3 with water
Rinsed for 0 seconds and dried. The pattern obtained by the above processing was observed with a scanning electron microscope, and the sensitivity, profile, critical resolution, and adhesion to the substrate were examined. Table 2 shows the results. The sensitivity was represented by an exposure amount for reproducing a 0.30 μm mask pattern. The critical resolution was defined as the critical resolution at an exposure amount that reproduced a 0.30 μm mask pattern. The adhesion was examined for the adhesion of 30 dot patterns of 0.20 μm, and the number of peeling patterns was examined.

[0078]

[Table 2]

As is clear from the results shown in Table 2, the resist composition using the polymer of the present invention was excellent in sensitivity and resolution, and all had a rectangular profile. In addition, no peeling of the pattern was observed, and there was no problem in adhesion.

[0080]

According to the present invention, a resist pattern having high sensitivity and resolution to deep ultraviolet rays, particularly ArF excimer laser light, excellent resist profile, and capable of forming a resist pattern which does not peel off from a substrate can be formed. A positive photosensitive composition having liquid suitability can be provided.
Therefore, it can be effectively used for forming a fine pattern required for manufacturing a semiconductor element, and the contribution to this kind of technology is extremely large.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenichiro Sato 4,000 Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Prefecture F-term in Fujisha Shin Film Co., Ltd. (Reference) 2H025 AA09 AA14 AB15 AB16 AB17 AC04 AC05 AC06 AC08 AD03 BE00 BG00 CC03 CC20

Claims (2)

[Claims] (1) The following general formula (I) and / or (I)
A polymer having the structural unit represented by I) and decomposing by the action of an acid, (b) a compound capable of generating an acid upon irradiation with actinic rays or radiation, and (c) a solvent. Positive photosensitive composition. General formula (I) General formula (II) (In the formulas (I) and (II), R ₁ and R ₂ each independently represent
It represents a hydrogen atom, a hydroxyl group, a halogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, an alkali-soluble group or a group which is decomposed by the action of an acid. ) 2. A compound having a group decomposable by the action of an acid and having an alkali solubility increased by the action of an acid, having a molecular weight of 1,000.
The positive photosensitive composition according to claim 1, comprising the following low-molecular acid-decomposable dissolution inhibiting compound.