JP3503976B2 - Pattern formation method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern forming method used for fine processing in a manufacturing process of electronic parts such as semiconductor integrated circuits.

[0002]

2. Description of the Related Art In the field of electronic parts such as semiconductor integrated circuits that require various fine processing, fine processing techniques including photolithography are adopted. Specifically, in such a technique, the following pattern forming process is carried out.

That is, first, a resist film is formed on a semiconductor substrate such as a silicon wafer by a spin coating method or the like. Next, this resist film is pattern-exposed to generate a photochemical reaction, and then subjected to development treatment, rinse treatment, etc. to form a desired resist pattern.

Further, by using the obtained resist pattern as an etching resistant mask, the exposed substrate portion is etched to form fine lines and openings. recent years,
In order to achieve high integration of electronic parts, it is required to form a sub-micron order fine resist pattern in the pattern forming process. As one of the measures, a single wavelength exposure light source is used. For example, ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm) and YAG laser 5
A pattern forming process has been developed that uses double harmonic light (wavelength 213 nm) as a light source.

On the other hand, in the pattern forming process, it is required to form a resist pattern having excellent dry etching resistance for the purpose of more effectively performing fine processing. In this regard, it is currently known that it is effective to form a resist film by using a photosensitive composition containing a compound having an aromatic ring, that is, an aromatic compound, as a resist material. As such a resist material, for example, an alkali-soluble novolac resin currently used in a mass production process of LSI,
A photosensitive composition containing a quinonediazide as a photosensitizer, and a chemically amplified resist disclosed in JP-A-63-27829, that is, an alkali-soluble resin having an aromatic ring, a dissolution inhibitor, and a photoacid generator. And a photosensitive composition containing.

[0006]

In the conventional pattern forming process, it has been attempted to form a high resolution resist pattern by using an exposure light source having a short wavelength as described above. On the other hand, attempts have been made to form a resist pattern having excellent dry etching resistance by using a photosensitive composition containing an aromatic compound as a resist material.

However, the above-mentioned resist material, that is, a photosensitive composition containing a conventionally known aromatic compound, is particularly short-wavelength region (about 190 nm) due to the excitation of electrons of the aromatic ring. The light absorption in is very strong. Therefore, when a resist film is formed using the resist material in a pattern forming process for performing exposure using a short-wavelength exposure light source as described above, the resist film may exhibit excessively strong light absorption during exposure. As a result, the photochemical reaction does not proceed sufficiently in the resist film.

This point will be described in more detail. It is known that the aromatic compound contained in the resist material usually has three absorption bands due to the structure of the aromatic ring. Of these, the first and second absorption bands from the long wavelength side are expressed because molecular excitation causes electronic excitation that cannot occur due to the original symmetry of the molecule, and are not so strong. On the other hand, the third absorption band is very strong.

In the pattern forming process, the aromatic compound is exposed to ultraviolet rays having wavelengths near the first and second absorption bands from the long wavelength side or wavelengths longer than these absorption bands as an exposure light source. When performing, the strong light absorption was not observed in the resist film.

However, when an exposure light source such as a short wavelength radiation is used, strong light absorption may occur in the resist film due to the third absorption band of the aromatic compound. In fact, when an exposure light source such as ArF excimer laser light is used for the resist film, the light transmittance is extremely low and the photochemical reaction does not proceed sufficiently over the entire resist film. As a result, a resist pattern with a desired resolution cannot be obtained.

As described above, in the conventional pattern forming method, when a short wavelength exposure light source is used, it is not possible to obtain a resist pattern exhibiting high resolution and excellent dry etching resistance, which is a problem. Has become.

The present invention has been made in view of the above problems and is applicable to photolithography in the manufacturing process of semiconductor devices and the like, and has high resolution and dryness even when an exposure light source of short wavelength is adopted. An object of the present invention is to provide a pattern forming method and a photosensitive composition capable of stably forming a resist pattern having excellent etching resistance.

The first to fourth pattern forming methods will be described below.
explain about. The first pattern forming method comprises a step of forming a photosensitive layer containing an aromatic compound on a substrate, and a third step from the long wavelength side in the absorption spectrum of the aromatic compound in the photosensitive layer. A step of pattern-exposing light having a wavelength shorter than the maximum wavelength of the absorption band and longer than the maximum wavelength of the fourth absorption band to cause a photochemical reaction in the photosensitive layer; and developing the photosensitive layer after the exposure. And selectively removing or leaving the exposed portion of the photosensitive layer.

Here, the "maximum wavelength of the absorption band" means the peak wavelength of the absorption band, that is, the wavelength of the absorption maximum. As described above, the absorption band of an aromatic compound is absorption accompanying the excitation of electrons in the aromatic ring, but does not include a very weak triplet electron transition. Strictly speaking, the third absorption band from the long wavelength side is a combination of two close absorptions, and is considered to be one in a symmetrical molecule.

The above-mentioned first method is, for a photosensitive layer containing an aromatic compound, a specific wavelength corresponding to the absorption spectrum of the aromatic compound, that is, the maximum of the third absorption band from the long wavelength side. It is most characteristic in exposing light having a wavelength shorter than the wavelength and longer than the maximum wavelength of the fourth absorption band. In other words, it is characteristic in that light having a specific wavelength according to the composition of the photosensitive layer is appropriately selected and exposed to cause a photochemical reaction. By adopting such exposure, the absorption of light is reduced and the transmittance is improved in the photosensitive layer, so that the photochemical reaction sufficiently progresses throughout the film thickness direction. As a result, it is possible to obtain a pattern having high resolution and also excellent in dry etching resistance due to the characteristics of the aromatic ring in the aromatic compound.

Hereinafter, the first method will be described in detail along with steps. First, as a first step, a solution (varnish) of a photosensitive composition containing an aromatic compound as an essential component is applied on a substrate by, for example, a spin coating method or a dipping method, and then at about 60 to 150 ° C. Preferably 80-
It is dried at 130 ° C. to form a photosensitive layer (resist film).

Examples of the substrate include a silicon wafer, a silicon wafer having various steps on the surface of which various insulating films and electrodes, and wiring are formed, a blank mask, a III-V compound semiconductor wafer such as GaAs. .

On the other hand, the photosensitive composition may be a commonly used resist material containing at least one aromatic compound.
Examples thereof include a polymer compound having an aromatic ring in the structure and the main chain of which can be cleaved by exposure, a resin composition containing a compound whose solubility is improved by exposure (positive resist), Examples include polymer compounds having an aromatic ring and capable of being crosslinked by exposure, and resin compositions (negative resists) containing compounds whose solubility deteriorates upon exposure. Among them, photochemical reaction after exposure is a thermal reaction. A chemically amplified resist that is amplified by is useful.

A specific example of the positive resist is a vinyl or acrylic compound having an aromatic ring such as a benzene ring, a naphthalene ring or an anthracene ring in its side chain,
Copolymer with methyl methacrylate, α-chloromethacrylate, trifluoroethyl α-chloroacrylate, trifluoromethyl acrylate, or an acrylic compound such as olefin sulfone, or the side chain has an aromatic ring such as benzene ring, naphthalene ring, or anthracene ring A resin composition containing a photosensitive compound such as a vinyl-based or acrylic-based compound having a polymer or a polysilane having an aromatic ring such as a naphthalene ring in a side chain, and a naphthoquinonediazide compound having an aromatic ring such as a naphthalene ring. The phenol resin contained is mentioned.

Specific examples of the negative resist include a vinyl or acrylic compound having an aromatic ring such as a benzene ring, a naphthalene ring or an anthracene ring in its side chain, an acrylic methacrylate, and an epoxy group in its side chain. A copolymer of methacrylate or an ester side chain with an acrylic compound having 4 or more carbon atoms, a resin composition containing a photosensitive compound such as polysiloxane having an aromatic ring such as naphthalene in the side chain, or naphthol. Examples thereof include a composition obtained by adding a photocrosslinking agent to a phenol resin having a different aromatic ring.

If desired, a sensitizer such as a bisazide compound may be added to these compositions. Moreover, the following are illustrated as a specific example of the said chemically amplified resist.

As the positive type chemically amplified resist, a vinyl or acrylic compound having an aromatic ring in the side chain and a tert-butyl ester such as tert-butyl methacrylate or tert-butoxycarbonyloxyvinylnaphthalene as a side chain are used. And a resin component composed of a copolymer with an acrylic or vinyl compound having a tert-butyl ester as a side chain, a compound capable of generating an acid upon exposure, that is, a photoacid generator, and, if necessary, Examples thereof include a compound having at least one bond capable of being decomposed by an acid, that is, a resin composition containing a dissolution inhibitor. In the composition, when the dissolution inhibitor is included, the resin component is te
It is not necessary to have rt-butyl ester, and it may be a copolymer containing as a component a vinyl compound having an alkali-soluble group such as methacrylic acid that gives alkali solubility.

Specific examples of the photoacid generator include sulfonyl, sulfonate compounds, 4-quinonediazide compounds, sulfonium salts and onium salts such as iodonium salts. Further, specific examples of the dissolution inhibitor include a tert-butoxycarbonyl compound, a tert-butyl ester compound, a pyranyl ether compound, a trimethylsilyl compound protected by an OH or COOH group, and the like. These photoacid generators and dissolution inhibitors may have a naphthalene ring or anthracene ring in the structure depending on the blending amount thereof.

In the positive chemically amplified resist, the compounding amount of each component can be set as follows. The blending amount of the acid generator varies depending on the strength of the generated acid, but is usually set in the range of about 0.5 to 30% by weight. Image quality may deteriorate. Further, the content of the dissolution inhibitor is usually set in the range of about 5 to 99% by weight, and even if it exceeds this range, the sensitivity of the resist may decrease or the resolution may decrease in the same manner as above. is there.

On the other hand, as the negative chemically amplified resist,
A resin component composed of a copolymer of a vinyl or acrylic compound having an aromatic ring in the side chain and an alkali-soluble acrylic or vinyl compound such as acrylic acid or vinyl naphthol, a photo-acid generator, and an acid A compound that can crosslink the coalescence, that is, a resin composition containing a photocrosslinking agent is included.

Specific examples of the photo-acid generator include compounds exemplified in the positive type, halogenated alkyl-substituted triazine and naphthyridine compounds.
Examples of the photo-crosslinking agent include vinyl having an epoxy group in a side chain, an acrylic copolymer, a methylol-substituted triazine, and a melamine compound such as a naphthyridine compound.

In the negative chemically amplified resist, the blending amount of each component can be set as follows. The content of the acid generator varies depending on the strength of the generated acid, but is usually set in the range of about 0.5 to 30% by weight, and the content of the photocrosslinking agent is preferably about 0.5 to 40. It can be set in the range of% by weight. If the blending amount of any component deviates from the above range, the sensitivity of the resist may be lowered, or the resolution may be lowered.

If necessary, a surfactant as a coating film modifier or a dye as an antireflection agent may be added to the photosensitive composition. The photosensitive composition can be prepared by dissolving each of the above-mentioned components and other additives in a suitable solvent and filtering.
Examples of such a solvent include water, cyclohexanone,
Acetone, methyl ethyl ketone, ketone type solvents such as methyl isobutyl ketone, methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve, ethyl cellosolve acetate, butyl cellosolve, cellosolve solvents such as butyl cellosolve acetate, ethyl acetate, butyl acetate, isoamyl acetate, ethyl lactate, Ester solvent such as methyl lactate, 2-butanol, isoamyl alcohol, alcohol solvent such as diethylene glycol, ethylene glycol diethyl ether, diethylene glycol monoethyl ether, polyhydric alcohol derivative solvent such as ethyl carbitol, morpholine, N-methyl- 2-pyrrolidone and the like can be mentioned. These solvents may be used alone or in the form of a mixture.

Next, in the second step following the first step, the maximum absorption wavelength of the third absorption band from the long wavelength side in the absorption spectrum of the aromatic compound contained in the photosensitive layer is measured. Pattern exposure is performed with light having a short wavelength and a wavelength longer than the maximum wavelength of the fourth absorption band to cause a photochemical reaction in the photosensitive layer. As a specific operation, ultraviolet rays satisfying the above conditions are pattern-exposed to the photosensitive layer through a mask having a desired pattern.

In this step, it is important to properly select the wavelength of the exposure line according to the above-mentioned rules, depending on the structure of the aromatic compound contained in the photosensitive layer, that is, the structure of the aromatic ring contained therein. For example, when the aromatic ring is a benzene ring, the exposure wavelength is within a range of about 170 to 150 nm, and when the aromatic ring is a naphthalene ring, the exposure wavelength is about 210.
When the aromatic ring is an anthracene ring in the region of ˜170 nm, the exposure wavelength can be set in the region of about 230 to 190 nm, respectively. In addition, these wavelength regions are
It varies depending on the substituent introduced into the aromatic ring. For example,
Even if any substituent such as a halogen group or a nitro group is introduced into the aromatic ring, it shifts to the long wavelength side by about 10 nm, and the substituent can be conjugated with the double bond of the aromatic ring. When it has a double bond, it shifts significantly to the low wavelength side.

In the step, by selecting the exposure wavelength as described above, the light absorption in the exposed portion of the photosensitive layer is reduced, the light transmittance is remarkably improved, and the photochemical reaction is sufficiently performed over the entire film thickness. You can proceed.

The photochemical reaction in the exposed portion of the photosensitive layer proceeds according to a different mechanism depending on the type of photosensitive composition constituting the layer. For example, in the exposed portion of the photosensitive layer made of the positive resist, the polymer chain of the resin component is cleaved to reduce the molecular weight, or an insoluble compound is changed into a soluble substance by a photochemical reaction. In the exposed portion of the photosensitive layer made of the negative resist, the polymer chains of the resin component are crosslinked to form a two-dimensional and three-dimensional molecular structure.

In the exposed portion of the photosensitive layer made of the chemically amplified resist, the photoacid generator generates an acid, and the acid decomposes the side chain of the resin component (in the case of a positive type), or The resin component is crosslinked by the activation of the photocrosslinking agent (in the case of a negative type). In this case, in particular, the photosensitive layer after the pattern exposure is heat-treated (post exposure bake: PEB) at a temperature of about 70 to 160 ° C., preferably 80 to 150 ° C., if necessary, to accelerate the amplification reaction. That is, the acid generated in the exposed portion of the photosensitive layer is diffused as described above, and the reaction between this acid and other components can be promoted. The reason for limiting the temperature in this heat treatment step is that if the temperature is lower than 70 ° C., it may be difficult to sufficiently carry out the above reaction, and if it exceeds 160 ° C.
This is because the exposed and unexposed areas of the radiation-sensitive layer may be decomposed or cured.

Next, as a third step following the second step, the exposed or heat-treated photosensitive layer is developed using a predetermined developing solution. Further, after washing away the developing solution with pure water, the substrate is dried.

In the third step (development process), either the exposed portion or the unexposed portion of the photosensitive layer, generally the exposed portion, is selectively dissolved in a developing solution and removed to give a predetermined pattern. Is formed. In particular, in the present invention, since the photochemical reaction in the exposed portion is sufficiently advanced in the previous step, the exposed portion and the unexposed portion have high selectivity and a high resolution pattern is formed.

The developer contains water or an organic alkali such as tetramethylammonium hydroxide,
A normal aqueous solution of an inorganic alkali, an alcohol solution or the like can be used. When a resist whose molecular weight is changed by a photochemical reaction is used, organic solvents such as methyl ethyl ketone, methyl isobutyl ketone ketones, and esters such as butyl acetate can be used as the developing solution.

Next, the second pattern forming method will be described. The second method according to the present invention is the method of
Structure of aromatic ring having 12 or more conjugated double bonds
For forming a photosensitive layer containing an aromatic compound contained therein
And the photosensitive layer has a wavelength of 180 nm or more and 220 nm or less.
Pattern exposure of the lower UV light, and photosensitization in the photosensitive layer
Of the photochemical reaction, and the photosensitive layer after exposure is subjected to a development treatment.
A pattern forming method comprising the steps of:
The aromatic ring having 12 or more and 12 or less conjugated double bonds is
75% by weight or more of all aromatic rings in the photosensitive layer 1
And the photosensitive layer is naphthylmethac
Characterized by containing a copolymer containing relate as a monomer
Pattern forming method, and 4 or more on the substrate 12
Includes in the structure an aromatic ring with the following conjugated double bonds
Forming a photosensitive layer containing an aromatic compound, and
Ultraviolet light having a wavelength of 180 nm to 220 nm in the photosensitive layer
The lines are pattern exposed to induce photochemical reactions in the photosensitive layer.
The process of producing and the process of developing the photosensitive layer after exposure.
A pattern forming method comprising:
The aromatic ring having the following conjugated double bond is
75% by weight or more and 100% by weight of all aromatic rings in the organic layer
% Or less, and the photosensitive layer has an epoxy group in the side chain.
Polymer containing vinyl compound, naphthalene ring in side chain
Having a vinyl compound-containing polymer, naphthalene as the skeleton
Containing polyhydroxy compounds, and of light or ionizing radiation
Contains compounds that generate acid or alkali upon irradiation
And a pattern forming method.

The term "conjugated double bond" as used herein means that the double bonds are connected to each other via a single bond and are aligned in a plane. Such an aromatic ring is usually cyclized by forming a 6-membered ring.

The second method of the present invention is the operation of forming a photosensitive layer, developing treatment and other treatments, and the solvent used,
The additives and the like are basically the same as those in the first method, but are characteristic with respect to the exposure and the constitution of the photosensitive layer, that is, the components of the photosensitive composition used. In detail, a limited wavelength (about 180 nm) is required to obtain a high-resolution pattern.
To 220 nm), for example, an ArF excimer laser (193 nm) or a wavelength five times higher than that of a YAG laser (213 nm) is adopted as a light source, and correspondingly, a compound having an aromatic ring of a specific structure is contained. The photosensitive layer is used.

In general, the wavelength region of about 180 to 220 nm is close to the absorption of an aromatic ring having 3 or less conjugated double bonds, for example, a benzene ring. Therefore, when a pattern is formed by using ultraviolet rays in the above wavelength range, a photosensitive composition containing a compound containing a benzene ring in its structure is used to improve the etching resistance of the pattern. The light transmittance of the resist film) is low, and the photochemical reaction due to exposure does not proceed sufficiently over the entire film thickness. Therefore,
In the second method, the absorption band is shifted to the short wavelength side by using an aromatic ring having four or more conjugated double bonds,
Absorption of ultraviolet rays in the above wavelength range is reduced. As a result, the light transmittance of the photosensitive layer at the time of exposure is improved, the photochemical reaction is sufficiently advanced throughout the film thickness direction, and the resolution is high. A pattern having excellent etching resistance can be obtained. As described above, in the second method, by appropriately selecting the structure of the aromatic ring of the aromatic compound contained in the photosensitive layer in response to ultraviolet rays having a limited wavelength, the exposure wavelength and the amount contained in the photosensitive layer can be increased. By avoiding overlapping with the absorption band of the aromatic compound, the light transmittance of the photosensitive layer is improved and a desired fine pattern is obtained.

Used in the second method of the invention. Four
To 12 are aromatic compounds having an aromatic ring having a conjugated double bond, and the aromatic ring is a molecular skeleton of a compound constituting the photosensitive layer, for example, a main chain skeleton or a side chain skeleton of a resin component,
It is introduced into the skeleton of other components. Specific examples are listed in the first method. In the skeleton of a compound that constitutes a general positive type resist, a negative type resist, and a chemically amplified resist, for example, in the main chain or side chain of a resin component, the skeleton of a photo-acid generator or a dissolution inhibitor, 4 to 12 Examples thereof include those in which an aromatic ring having a conjugated double bond is introduced.

The aromatic ring having a conjugated double bond of 4 to 12 has, for example, a skeleton such as a benzene ring or a pyridine ring in which one or more atoms bonded to the ring are double-bonded to other atoms. It is a ring. As a specific example, -R ₁ = R ₂
- or _{-R 3 (= R 4) -} (R 1 is R ₂ is 1-substituted carbon atom or a nitrogen atom, R ₃ is 1-substituted carbon atom, R ₄ is an oxygen atom,
Examples thereof include a benzene ring skeleton and a pyridine ring skeleton substituted with a unit represented by a mono-substituted nitrogen atom or a di-substituted carbon atom.

Further, the aromatic ring may be a composite ring formed by the above-mentioned benzene ring, pyridine ring and other monocycles in view of excellent flatness. Examples of the complex ring include pyrrole, benzofuran, benzothiophene, indole, benzoxazole, benzothiazole, indazole, chromene, quinoline, cynoline, phthalazine, quinazoline, dibenzofuran, carbazole, acridine, phenanthridine,
Examples thereof include phenanthroline, phenazine, thianthrene, indolizine, naphthyridine, purine, pteridine, fluorene, benzoquinone, phthalimide and phthalic anhydride skeleton.

When the aromatic ring having a conjugated double bond of 4 to 12 is a 6-membered bonded aromatic ring, it is desirable in that the dry etching resistance of the obtained pattern is remarkably improved. Examples of such a complex ring include naphthalene, anthracene, phenanthrene, pyrene, naphthacene, chrysene, 3,4 benzophenanthrene, perylene, pentacene and picene. Biphenylene and biphenyl also have a structure that imparts excellent dry etching resistance. In particular, when the aromatic ring is selected from naphthalene, anthracene, and phenanthrene, the transparency and dry etching resistance of the pattern are finally increased.

[0045] In the above second method, 4 to 12 co
The aromatic ring having a double bond that plays a role in all of the aromatic rings in the photosensitive composition.
It is 75 to 100% by weight of all aromatic rings. The reason for this
Is too small, it may hinder the light transmission of the photosensitive layer.
Because there is. Further, the amount of the specific aromatic compound in the solid content of the photosensitive composition is preferably at least 10% by weight and less than 90% by weight. The reason for this is that if the amount of the aromatic compound is less than 10% by weight, the dry etching resistance of the obtained pattern is lowered, and conversely if it is 90% by weight or more, the light transmittance of the photosensitive layer may be lowered. Because there is. More preferable amount of the aromatic compound is 20 to 50% by weight.

The aromatic ring is a hydroxyl group or OR '(R'
Is substituted with a hydroxyl-protecting group such as a tert-butyl group or a tert-butoxycarbonyl group), the compound containing the aromatic ring is finally imparted with alkali solubility after exposure. Therefore, it is very suitable for a pattern forming process that employs an alkali developing process. Further, when the aromatic ring is substituted with a sulfonic acid group or a salt thereof, or an amino group or a salt thereof, the compound containing the aromatic ring is imparted with water solubility, and thus a pattern employing a water development treatment is used. Suitable for forming process.

The photosensitive composition (resist) containing an aromatic compound having a specific aromatic ring as described above preferably has a melting point of 50 ° C. or higher, and has a coating property with respect to water or an organic solvent. Those with high solubility are desirable.

As the photosensitive composition containing the aromatic compound having an aromatic ring having a conjugated double bond of 4 to 12, the following photosensitive composition (A) is mentioned as a suitable photosensitive composition. To be The compound (A) has a skeleton

[0049]

[Chemical 1] And an acetal resin having at least one structural part of the following (2), (3), and (4), an epoxy compound having a naphthalene ring in the skeleton, and a compound that generates an acid or an alkali upon irradiation with light or ionizing radiation. It is a photosensitive composition consisting of.

[0050]

[Chemical 2]

The acetal resin in the photosensitive composition (A) is made of polyvinyl alcohol as a raw material and
An aldehyde having a substituent of _{5 to} R ₇ is used with an acid catalyst,
Obtained by the method of acetalization. According to the above method, as a residual unreacted portion of polyvinyl acetate which is a raw material of polyvinyl alcohol, the above (1) to
Besides (4),

[0052]

[Chemical 3] Remain, but may have this structural portion (5). The acetal resin preferably has a molecular weight of 1,000 or more and 300,000 or less. If it deviates from this range, the solubility in the solvent is significantly impaired.

In the above acetal resin, the total amount of the structural portion (2) varies depending on the solvent in which the resin is dissolved, but when dissolved in water or an alcohol solvent, it is 50
mol% or less is preferable, and when dissolved in an organic solvent other than water or alcohol solvent, the total amount is 50 mol.
% Or more is preferable. If it deviates from these ranges, the solubility in a solvent will be significantly impaired. Further, the structural portion of (3) or (4) in the acetal resin is 5
It is preferably 0 mol% or less. If it deviates from this range, a cross-linking reaction between the resins occurs in the synthesis process, and the desired resin cannot be obtained.

The structural portion (3) above is introduced to promote the solubility in acid, and the structural portion (4) is introduced in order to promote the solubility in alkali, and at least 1 mol% or more of each is introduced. Is preferred. More preferably, it is 5 mol% to 30 mol%.

As the compound which generates an acid by light or ionizing radiation in the photosensitive composition (A), that is, the compound which generates an acid by exposure (photoacid generator), an onium salt, orthoquinonediazide sulfonate is used. , Sulfonyl compounds, sulfonates,
Examples thereof include organic halides. Examples of the onium salt include a fluoroborate anion, a hexafluoroantimonate anion, a hexafluoroarsenate anion, a trifluoromethanesulfonate anion, or a diazonium salt having a paratoluenesulfonate anion as a counter ion, a phosphonium salt, and a sulfonium salt. Examples thereof include salts. Of these, onium salts of trifluoromethane sulfonic acid and triaryl sulfides, and onium salts of diaryl sulfides and diaryl iodides are preferable because of their high sensitivity. Examples of the sulfonyl compound include allyl sulfonyl methane derivatives, diallyl disulfonyl methane derivatives, diallyl methyl disulfonyl methane derivatives, methyl sulfonyl methane derivatives, dimethyl sulfonyl methane derivatives and diazo compounds thereof as described in Japanese Patent Application No. 4-53729. And the like, for example, bis (phenylsulfonyl) methane or phenylsulfonylacetonitrile, 1-methyl-2
((Phenylsulfonyl) methyl) benzene and the like are preferable. The organic halide is a compound that forms hydrohalic acid and is disclosed in US Pat. No. 3,515,552,
US Patent No. 3536489, US Patent No. 377977
8 and West German Patent Publication No. 2243621. Other photoacid generators include JP-A-54-74728, JP-A-55-24113, JP-A-55-77742, JP-A-60-3626, and JP-A-60-. No. 138539, Japanese Patent Laid-Open No. 50-
The compound disclosed in 36209 may be used.

Illustrative examples of the above photo-acid generators include:
Di (paratertiary butylbenzene) diphenyliodonium trifluoromethanesulfonate, benzointosylate, orthonitrobenzyl paratoluene sulfonate, triphenylsulfonium tricleolomethanisulfonate, tri (tert-butylphenyl) sulfonium trifluoromethanesulfonate, benzenidiazonium para Toluene sulfonate, 4- (di-n-propylamino) -benzonium tetrafluoroborate,
4-P-tolyl-mercapto-2,5-diethoxy-benzenediazonium hexafluorophosphate, tetrafluoroborate, diphenylamine-4-diazonium sulfate, 1,8-naphthalimidyl triflate, naphthalene-containing onium salt, (NAT- 103, NAT-105, NDS-103, ND
S-105 Acid generator (Midori Chemical Co., Ltd .: CAS [131582-00-8],
[137867-61-9] and [110098-97-0])), 4-methyl-6-
Trichloromethyl-2-pyrone, 4- (3,4,5-trimethoxy-styryl) -6-tricorochloromethyl-2-pyrone, 4- (4-
Methoxy-styryl) -6- (3,3,3-trichloro-propenyl) -2-pyrone, 2-trichloromethyl-benzimidazole, 2-tribromomethyl-quinolone, 2,4-domethyl
-1-Tripromoacetyl-benzene, 4-dibromoacetyl-benzoic acid, 1,4-bis-dibromomethyl-benzene,
Tris-dibromomethyl-S-triazine, 2- (6-methoxy-naphthyl-2-yl) -4,6-bis-trichloromethyl
-S-triazine, 2- (naphthyl-1-yl) -4,6-bis-
Trichloromethyl-S-triazine, 2- (naphthyl-2-yl) -4,6-bis-trichloromethyl-S-triazine, 2-
(4-Ethoxyethyl-naphthyl-1-yl) -4,6-bis-
Trichloromethyl-S-triazine, 2- (benzopyrani-3
-Yl) -4,6-bis-trichloromethyl-S-triazine, 2- (4-methoxy-anthrac-1-yl) -4,6-bis-trichloromethyl-S-triazine, 2- (phenanth-9)
-Yl) -4,6-bis-trichloromethyl-S-triazine, o-naphthoquinonediazide-4-sulfonic acid chloride and the like.

The amount of the photo-acid generator blended with other solids cannot be unconditionally defined depending on the acid-generation efficiency of the photo-acid generator, but is usually 0.01 to 20 parts by weight, more preferably 0. Desirably, the range is 2-10 parts by weight.
The reason is that if the amount of the acid generator is less than 0.01% by weight, the compounding effect is insufficient, while if it exceeds 20 parts by weight, the coating property may be deteriorated.

Examples of the compound that generates an alkali upon exposure to light or ionizing radiation, that is, the compound that generates an alkali upon exposure (photo-alkali generator) include a carbamate compound and a sulfonamide compound. Among them, nitrobenzyl cyclohexyl carbamate, dimethoxybenzyl cyclohexyl carbamate,
N-cyclohexyl-methylphenyl sulfonamide, N-cyclohexyl-naphthyl sulfonamide and the like can be preferably used. The amount of such a photo-alkali generator mixed with other solids cannot be unconditionally defined depending on the generation efficiency of the photo-alkali generator, but it is usually 0.1-20.
It is desirable that the amount is in the range of 0.5 to 10 parts by weight, preferably 0.5 to 10 parts by weight. The reason for this is that if the content of the photo-alkali generator is less than 0.1% by weight, the compounding effect will be insufficient, while if it exceeds 20 parts by weight, the coating property may deteriorate.

The photosensitive composition (A) has a markedly increased sensitivity by containing an epoxy compound having a naphthalene ring in the skeleton. The epoxy compounds containing the naphthalene ring in the skeleton are all naphthalene compounds having at least one, and more preferably at least two epoxy groups in at least one molecule, but polyhydroxynaphthalene compounds can be obtained by epichlorohydrin in the presence of a base. Epoxidized compounds and epoxy resins are preferably used.
Examples of the polyhydroxynaphthalene compound include naphthols such as dihydroxynaphthalene and naphthol novolak compounds obtained by condensing them with formaldehyde. The blending amount of the epoxy compound with respect to the other solid content cannot be unconditionally defined depending on the molecular weight of the epoxy compound, but is usually 1 to 70 parts by weight, more preferably 5 to 5 parts by weight.
The preferred range is 0 parts by weight. The reason for this is
If the compounding amount of the epoxy compound is less than 1% by weight, the compounding effect will be insufficient, while if it exceeds 70 parts by weight, heat resistance, coatability and light transmittance may be deteriorated.

The photosensitive composition (A) is a highly transparent photosensitive composition in which an acetal resin having a specific structure is crosslinked with high sensitivity by the action of a photoacid / base generator. The acetal resin can be used as a negative resist because an intramolecular crosslink is transferred to an intermolecular crosslink by an acid or a base to cause crosslink, insolubilization and film shrinkage. To the photosensitive composition based on this acetal resin, an epoxy compound is added to increase the cross-linking efficiency to further improve the sensitivity.Since the epoxy compound has a naphthalene skeleton, the carbon content is increased and the dryness is increased. The etching resistance could be improved. In the naphthalene skeleton, the energy of double bond excitation is reduced by conjugation and the transparency of 180 to 220 nm can be improved, so that the light transmittance of 180 to 220 nm wavelength can also be improved.

Further, a photosensitive composition suitable as a photosensitive composition containing an aromatic compound containing an aromatic ring having 4 to 12 conjugated double bonds includes a vinyl compound having an epoxy group in a side chain. Examples thereof include a photosensitive composition (B) containing a polymer, a polyhydroxy compound containing a naphthalene ring in the skeleton, and a compound capable of generating an acid or an alkali upon irradiation with light or ionizing radiation.

Examples of the polymer containing a vinyl compound having an epoxy group in its side chain include a polymer of dimethacrylate, a polymer of allyl glycidyl ether, a polymer of 1,2-epoxy 5,9-cyclododecandiene, 1,2-epoxy
Examples thereof include polymers of 5-hexene and polymers of methylvinyloxirane.

As the polymer containing a vinyl compound having an epoxy group as a side chain, a vinyl compound having an epoxy group as a side chain, a vinyl compound having an aromatic ring as a side chain, and a carboxylic acid as a side chain are particularly preferable. A terpolymer of a vinyl compound can improve dry etching resistance and alkali solubility of the photosensitive composition.

Examples of the vinyl compound having an aromatic ring as a side chain include styrene, vinylnaphthalene, vinyl anthracene,
Examples thereof include vinylcarbazole, vinylphenol, vinylnuthol, and chloromethylstyrene.

Examples of the vinyl compound having a carboxylic acid in its side chain include acrylic acid, methacrylic acid and maleic anhydride. These acids may be protected with a trimethylsilyl group, a tertiary butyl group or the like during the copolymerization and then deprotected later to generate a carboxyl group as a result.

The composition ratio in the above terpolymer is 5 to 40 mol% of the vinyl compound having an epoxy group in the side chain.
10 to 60 mol of vinyl compound having an aromatic ring in the side chain
% And vinyl compounds having carboxylic acid in the side chain are 10
It is preferably in the range of 50 mol%. If it deviates from this range, any one of sensitivity, alkali solubility and dry etching resistance may be deteriorated.

Further, this photosensitive composition contains a polyhydroxy compound containing a naphthalene ring in the skeleton as a crosslinking agent. Examples of the polyhydroxy compound include naphthols such as dihydroxynaphthalene and naphthol novolak compounds obtained by condensing them with formaldehyde. The blending amount of the polyhydroxynaphthalene compound in the other solid content can be defined by the amount of the epoxy group of the other solid content. Usually 1-50 of total epoxy
Desirably, the amount is in the range of 5 parts by mole, more preferably 5-50 parts by mole. The reason for this is that if the amount of the polyhydroxy compound compounded is less than 1% by weight, the compounding effect will be insufficient, while if it exceeds 50 parts by mol, the coatability and solubility may deteriorate.

Further, a compound capable of generating an acid or an alkali by the above light or ionizing radiation is added. As the compound used in the photosensitive composition (B) to generate an acid or an alkali by light or ionizing radiation, the photosensitive composition (A)
The same compounds as those used for can be mentioned. Moreover, the blending amount thereof is the same as that of the photosensitive composition (A).

The photosensitive composition (B) is a highly transparent photosensitive composition in which a vinyl polymer having an epoxy group in its side chain is crosslinked with high sensitivity by a photoacid and an alkali generator. A vinyl polymer having an epoxy as a side chain can be used as a negative resist by causing cross-linking, insolubilization and film shrinkage by an acid or a base. By adding an appropriate amount of a polyhydroxy compound to a vinyl polymer having an epoxy group in the side chain, the crosslinking efficiency is increased, and further higher sensitivity and improved solubility of the unexposed area are achieved. Since it has an aromatic ring, it was possible to improve dry etching resistance. Further, since the aromatic ring contains a naphthalene skeleton, it is possible to improve the light transmittance at a wavelength of 180 to 220 nm.

The photosensitive composition (A) and the photosensitive composition (B) are prepared by dissolving the above resin and additives in water or an organic solvent and filtering.
Examples of the organic solvent include ketone solvents such as cyclohexanone, acetone, methyl ethyl ketone, and methyl isobutyl ketone, methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, cellosolve solvents such as butyl cellosolve acetate, ethyl acetate, butyl acetate, isoamyl acetate, and the like. Examples include ester solvents such as γ-butyl lactone, dimethyl sulfoxide, and dimethylformamide N-methylpyrrolidone. These organic solvents may be used alone or in the form of a mixture. In addition, these may contain an appropriate amount of an aliphatic alcohol such as xylene, toluene or isopropylyl alcohol.

Further, in addition to the above-mentioned components, the above-mentioned photosensitive composition may contain a surfactant as a coating film modifier, or other polymer such as polymethylmethacrylate, if necessary.
Polymethyl acrylate, propylene oxide-ethylene oxide copolymer, polystyrene, or a dye as an antireflection agent may be added.

Next, a description will be given of the third pattern formation method. A third pattern forming method is a step of forming a photosensitive layer containing an aromatic compound and a compound that emits fluorescence upon exposure on a substrate, and exposing the photosensitive layer to pattern exposure to generate fluorescence. Causing a photochemical reaction in the photosensitive layer by the action of incident light and fluorescence;
And developing the exposed photosensitive layer to selectively remove or leave the exposed portion of the photosensitive layer.

Also in the third method , the operation of forming the photosensitive layer, the current processing, other processing, and the solvent used,
The additives and the like are basically the same as those in the first method, but are characteristic with respect to the exposure and the constitution of the photosensitive layer, that is, the components of the photosensitive composition used. Specifically, it is characteristic in that a photosensitive layer containing a compound that emits fluorescence upon exposure is used. According to such a method, fluorescence is generated during exposure in the photosensitive layer, and a photochemical reaction is caused by the actions of both the fluorescence and incident light. In particular, this fluorescence is generated in the photosensitive layer and has a wavelength longer than that of incident light such as ultraviolet rays having a short wavelength. Therefore, the fluorescence and / or reactivity in the layer are excellent. Therefore, in the photosensitive layer, even if the transmittance of incident light is reduced due to the aromatic ring contained in the layer, the photochemical reaction is sufficiently advanced by the action of fluorescence, and finally the resolution is high, and A pattern excellent in dry etching resistance can be obtained.

The compound which emits fluorescence upon exposure contained in the photosensitive layer is, for example, the aromatic compound exemplified in the first and second methods, which is a compound having a structure in which the symmetry of the molecule is broken. Can be used. In particular, the compound containing an aromatic ring having 4 to 12 conjugated double bonds in the structure, which is used in the second method, can fluoresce very strongly upon exposure. In this case, the fluorescent compound and the aromatic compound contained in the photosensitive layer may be regarded as the same compound.

In addition, various fluorescent dyes can be used as the compound that emits fluorescence upon exposure. In addition, various fluorescent dyes can be added to the above-mentioned aromatic compounds to enhance the effect of fluorescence generation. Specific examples of the fluorescent dye include acridine orange, aminoacridine, quinacrine, anilinonaphthalene sulfonic acid derivative, anthroyloxystearic acid, auramine O, chlorotetracycline; merocyanine,
Cyanine dyes such as 1,1'dihexyl-2,2'oxacarbocyanine; dansyl chloride derivatives such as dansyl sulfamide, dansyl choline, dansyl galactoside, dansyl tolidine, dansyl chloride, diphenyl hexatriene, eosin, ε Adenosine, ethidium bromide, fluorescein, fomycin, 4-benzoylamide 4'aminostilbene 2,2 'sulfonic acid, β
Naphthyl triphosphate, oxonol dye, parinaric acid derivative, perylene, N-phenylnaphthylamine, pyrene,
Safranine O, fluorescamine, fluorescein isocyanate, 7-chloro 4 nitrobenzo 2 oxa 1,3 diazole, dansyl aziridine, 5- (iodoacetamidoethyl) aminonaphthalene 1 sulfonic acid, 5 iodoacetamido fluorocein, N- (1 ani Renonaphthyl 4)
Maleimide, N- (7 Dimethyl 4 Methylcoumanyl Maleimide, N- (3-Pyrene) Maleimide, Eosin 5 Iodoacetamide, Fluorescein Mercury Acetate, 2-
[4 '(2 "iodoacetamide) aminonaphthalene, 6
Examples thereof include sulfonic acid, eosin, and rhodamine derivatives. The blending amount of these fluorescent dyes is preferably at least 1% by weight to 50% by weight in the solid content of the photosensitive composition (resist). If the content of the fluorescent dye is less than 1% by weight, there is no effect of increasing the sensitivity and there is a possibility that the resolution and the sensitivity exceeding 50% by weight will be adversely affected.

In the third method, since a compound that emits fluorescence is used in the photosensitive layer to accelerate the photochemical reaction in the photosensitive layer, exposure rays of any wavelength can be used. Specific examples thereof include ultraviolet rays, far ultraviolet rays, vacuum ultraviolet rays, synchrotron orbital radiation light, electron beams, X-rays, gamma rays, and ion beams.

Next, the fourth pattern forming method will be described. A fourth method is a step of laminating a photosensitive layer containing an aromatic compound and a fluorescence generating layer containing a compound that emits fluorescence upon fluorescence on a substrate, and patterning the photosensitive layer and the fluorescence generating layer. Exposing and generating fluorescence in the fluorescence generating layer, and causing a photochemical reaction in the photosensitive layer by the action of incident light and fluorescence; and developing the photosensitive layer and the fluorescence generating layer after the exposure, And selectively leaving or leaving the exposed portion of the functional layer.

The fourth method is an application of the third method. Specifically, it is characteristic in that the compound which emits fluorescence upon exposure contained in the photosensitive layer in the third method is mixed with an appropriate resin component to form another layer, that is, a fluorescence generating layer. . According to this method, in the photosensitive layer, the photochemical reaction is sufficiently advanced by the action of both the fluorescence and the incident light generated in the fluorescence generating layer during exposure, and finally the resolution is high and the dry etching resistance is excellent. You can get the pattern.

In the fourth method, for example, an inorganic fluorescent agent can be used as the compound constituting the fluorescence generating layer. Examples of such a fluorescent agent include salts commonly used in fluorescent paints, fluorescent lamps, CRT phosphors, pigments and the like. As a specific example, MgW
O ₄ , CaWO ₄ , (Ca, Zn) (PO ₄ ) ₂ : Tl
⁺ , Ba ₂ P ₂ O ₇ : Ti, BaSi ₂ O ₅ : Pb ²⁺ ,
Sr ₂ P ₂ O ₇ : Sn ²⁺ , SrFB ₂ O _3.5 : Eu ²⁺ ,
Examples thereof include inorganic acid salts such as MgAl ₁₆ O ₂₇ : Eu ²⁺ and tungstate.

Since these inorganic fluorescent agents generally have insufficient solubility, they are made into a fine powder and dispersed in a suitable solvent together with a polymer binder, and the mixture system is applied to form a layer. Can be formed. The binder may be a polymer material in which the fluorescent agent is easily dispersed, but a water-soluble polymer is preferable in consideration of forming a multilayer with the photosensitive layer. Examples of such polymer materials include copolymers of polyvinyl alcohol, maleic acid and acrylic acid with vinyl and acrylic compounds. Further, the fluorescent agent and the polymer binder may be dispersed or dissolved in a solvent, but a surfactant or a dispersant may be added if necessary.

The thickness of the fluorescence generating layer is preferably in the range of about 0.05 to 0.5 μm. If it deviates from this range, the sensitivity or resolution of the photosensitive layer may be significantly lowered.

The fluorescence generating layer may be formed as either an upper layer or a lower layer of the photosensitive layer. When it is formed as an upper layer of the photosensitive layer, first, a mixed system containing the compound that emits fluorescence is applied to the photosensitive layer formed in the same manner as in the first to third methods in the thickness described above. . Then, baking is performed at a temperature of about 70 to 120 ° C. to disperse the solvent in the mixed system to obtain a fluorescence generating layer. Subsequently, exposure is performed in the same manner as in the third method, and if necessary, heat treatment is performed to remove the fluorescence generation layer with a suitable solvent or a developing solution, and then the exposed photosensitive layer is subjected to a development treatment to form a pattern. obtain.

On the other hand, when the fluorescence generating layer is formed as the lower layer of the photosensitive layer, the fluorescence generating layer is first formed on the substrate in the same manner as above. Subsequently, on this layer, similarly to the third method, formation of a photosensitive layer, exposure, heat treatment if necessary, and development treatment are performed to obtain a pattern. In this case, the fluorescence generating layer can be washed with the binder polymer by a spray method or can be peeled by a dry etching method. In particular, the latter method is preferable, but in this case, CF ₄ or HB is used as an etching gas.
r can be used.

When the fluorescence generating layer is formed as the lower layer of the photosensitive layer as described above, it is possible to further promote the photochemical reaction in the lower region where the incident light is hard to reach in the photosensitive layer.

[0085]

【Example】

(Example 1) In the following Synthesis Examples 1 and 2, the resin components blended in the photosensitive composition were synthesized. Synthesis Example 1 0.3 mol of 2 naphthyl methacrylate and 0.7 mol of tert-butyl methacrylate were mixed with 200 g of toluene, and 2 g of azoisobutyl nitrile (AIBN) was added. After heating the mixed system at a temperature of 70 ° C. for 8 hours,
The mixture was added dropwise to an acetone-methanol solvent for purification to obtain a copolymer of naphthyl methacrylate and tert-butyl methacrylate (resin A).

In addition, naphthyl methacrylate in the above process is replaced by vinylnaphthalene, vinylanthracene,
Replaced with vinylcarbazole, each had a copolymer composition of 3: 7 te
Copolymer with rt-butyl methacrylate (Resin DF)
Got

In addition, a commercially available β-naphthol novolak (resin C) was prepared. Each resin composition is as follows. Synthesis Example 2 1-hydroxy 2-naphthyl aldehyde was mixed with sodium ethoxide and ethanol was removed to obtain a sodium salt of 1-hydroxy 2-naphthyl aldehyde. Then, benzoyl chloride was added dropwise to obtain 1-benzoyloxy-2-naphtholaldehyde. 0.9 mol of malonic acid was added to 0.25 mol of 1-benzoyloxy 2 naphtholaldehyde, 10 cc of pyridine was further added, and the mixture was reacted at a temperature of 110 ° C. for 2 hours to obtain 1-benzoyloxy 2 (βcarboxy) vinylnaphthalene. 0.14 mol of 1 benzoyloxy 2 (β-carboxyvinylnaphthalene) was added to 100 cc
Dissolved in quinoline, add 5 g of copper powder, and add a temperature of 22
Reaction was carried out at 0 ° C. for 1 hour to obtain 1 benzoyloxy 2 vinylnaphthalene. Then, 0.1 mol of 1-benzoyloxy-2 vinylnaphthalene was polymerized using AIBN in benzene in the same manner as in Synthesis Example 1 to obtain poly (1 benzoyloxynaphthalene). This poly (1 benzoyloxyvinylnaphthalene) 0.5 mol monomer equivalent was dissolved in acetone, and 1 g of 1N sodium hydroxide aqueous solution was further added.
And heat to add poly (vinylnaphthol) (resin B)
Got The obtained polymer was reprecipitated with acetone and a water-oxalic acid solution for purification.

The composition of each resin is as follows. Resin A ... Copolymer of naphthyl methacrylate and tert-butyl methacrylate (molecular weight 20000, copolymer composition 3: 7) Resin B ... Poly (vinyl naphthol) (molecular weight 7000) Resin C ... β naphthol novolak (commercial product: molecular weight) 45
00) Resin D ... Copolymer of vinyl naphthalene and tert-butyl acrylate (molecular weight 6000, copolymer composition 3: 7) Resin E ... Copolymer of vinyl anthracene and tert-butyl acrylate (molecular weight 5500, copolymer composition : 3:
7) Resin F ... Copolymer of vinylcarbazole and tert-butyl acrylate (molecular weight 7,000, copolymer composition 3: 7) In addition, the following resins G to I were prepared. Incidentally, these resins do not contain an aromatic ring in the structure.

Resin G ... Poly tert-butyl acrylate (molecular weight 12500) Resin H ... polyallyl methacrylate (molecular weight 2400)
0) Resin I ... Polyglycidyl methacrylate (molecular weight 200
00) In addition, in Synthesis Examples 3 and 4 below, a compound (dissolution inhibitor) having a bond capable of being decomposed by an acid contained in the photosensitive composition was synthesized. Synthesis Example 3 Polyvinylnaphthol B was reacted with sodium hydride to form part of the hydroxyl groups of polyvinylnaphthol as a sodium salt. Then, di-tert-butyl dicarbonate was reacted to introduce a tert-butoxycarbonyl group to obtain a compound (a) having a bond capable of being decomposed by an acid. The introduction rate of the tert-butoxycarbonyl group in this compound is
It was 20 mol% with respect to all the hydroxyl groups of polyvinyl naphthol. Synthesis Example 4 Polyvinylnaphthol was reacted with bromoacetic acid tert-butyl ester using potassium carbonate and potassium iodide as catalysts, tert-butyl acetate was introduced, and a compound (b) having a bond capable of being decomposed by an acid was obtained. . The introduction rate of tert-butyl acetate in this compound was 19 mol% with respect to all the hydroxyl groups of polyvinyl naphthol.

In addition, the following compounds having a bond capable of being decomposed by an acid were prepared. Compound c ... tert-Butoxycarbonylnaphthol compound d ... Acetate tert-butylated naphthol compound e ... Tri (tert-butoxycarbonyl) anthralobin compound f ... tert-Butoxycarbonyloxyphenanthrene Further, according to Synthesis Example 5 below, photosensitivity is obtained. A photo-acid generator incorporated into the composition was synthesized. Synthesis Example 5 0.2 mol of anthralobin was dissolved in tetrahydrofuran, methanesulfonyl chloride was added in a 3-fold molar amount, and 0.6 mol of triethylamine was gradually added dropwise.
Then, triethylamine and tetrahydrofuran were removed and then recrystallized to obtain anthralobin tri (methanesulfonate) (compound g).

In addition, the following photoacid generators (compounds h to
j) was prepared. Compound h ... Naphtholnaphthoquinonediazide 4 sulfonate compound i ... Triphenylsulfonium triflate compound j ... Methylsulfonylacetonitrile A photocrosslinking agent (compound k) shown below was prepared. Compound k ... Melamine resin (Cymel 325) Preparation of Photosensitive Composition (Resist) The compounds (components) as described above were blended according to the formulation shown in Table 1 to prepare Photosensitive Compositions 1-17. That is, to the solid content of the components having the above blending ratio, 3 times its weight of ethyl cellosolve was added, and the mixture was stirred at room temperature for 6 hours, and then filtered through a Teflon filter having a pore size of 0.2 μm,
A solution (varnish) of the photosensitive composition was prepared.

[0092]

[Table 1]

A pattern was formed using the above photosensitive composition. Each of the photosensitive compositions 1 to 17 (solution) shown in Table 1 was spin-coated on a 5-inch silicon wafer and prebaked on a hot plate at 110 ° C. for 5 minutes to form a photosensitive layer having a thickness of 0.9 μm. (Resist film) was formed.

Next, the photosensitive layer was pattern-exposed (contact exposure) with ArF excimer laser light (wavelength 193 nm), and then baked on a hot plate at 110 ° C. for 2 minutes. Then, the wafer was exposed to the developing solution shown in Table 2
The photosensitive layer was developed by immersion for 0 to 200 seconds. Further, by washing with water and drying, a pattern consisting of predetermined lines and spaces was obtained.

The embodiment corresponds to the first and second methods . The obtained pattern was observed with a scanning electron microscope (hereinafter abbreviated as SEM) to evaluate the resolution. The results of the sensitivity and resolution (line width of the pattern) of the photosensitive layer (photosensitive composition) in each pattern formation are also shown in Table 2 below.

[0096]

[Table 2]

Of the resin components in the photosensitive composition 3, resin B is poly (vinylphenol) (molecular weight 600
It changed to 0) and prepared the photosensitive composition 26 for comparison. An attempt was made to form a pattern by ArF excimer laser exposure using the photosensitive composition 26 according to the same method and conditions as in Example 1, but a sufficient pattern could not be obtained even after 500 mJ exposure.

Further, in Example 1, the photosensitive composition 3 was used.
The pattern obtained by using as an etching resistant mask,
When reactive ion etching was performed using CF ₄ plasma, the etching rate was 47 mm / min. Met.

For comparison, a resist made of polymethylmethacrylate (PMMA) was used to form a pattern on the substrate in accordance with the method and conditions of Example 1, and this pattern was used as an etching resistant mask, and the reactive ion was used in the same manner as above. When etching was performed, the etching rate was 140 mm / min. Met.

From the above results, the patterns obtained by the examples of the present invention have a dry etching resistance that is about three times as high as that of the patterns obtained by using PMMA and ArF excimer laser exposure. It is clear. (Example 2) A resin composition blended in the photosensitive composition was synthesized and prepared as follows.

A commercially available acetal resin S-REC BLS (manufactured by Sekisui Chemical Co., Ltd.) (acetalization rate 70 mol%) (Resin J) was prepared as an acetal resin to be blended in the photosensitive composition.

Further, in Synthesis Examples 6 and 7, other acetal resins K and L compounded in the photosensitive composition were synthesized. Synthesis Example 6 2 g of polyvinyl alcohol (molecular weight 22500), 3 ml of glyoxylic acid, 4.5 ml of concentrated sulfuric acid, and 30 ml of water
, And reacted at 60 ° C. for 48 hours. After the reaction, the solution was neutralized with sodium hydroxide and re-reproduced with water-methanol to obtain glyoxyl oxide of polyvinyl alcohol (resin K).
(Acetalization rate is 20 mol%) Synthesis Example 7 Aminoacetalized polyvinyl alcohol (Resin L) was synthesized from polyvinyl alcohol (molecular weight 22500) according to the literature (Colloid Polym Sci. 252, 294 (1974)). (Amino acetalization rate is 6%) As the epoxy resin blended in the photosensitive composition, the epoxy resin blended in the photosensitive composition in Synthesis Examples 8 and 9 was synthesized. Synthesis Example 8 0.1 mol of epichlorohydrin in 0.05 mol of 1,5 naphthalene diol, 0.25 g of water and NaOH
After adding 4.0 g at 80 ° C. and reacting for 2 hours, unreacted epichlorohydrin was removed at 30 mmHg, and the epoxy resin was extracted with toluene. Toluene was distilled off under reduced pressure to obtain an epoxy resin (resin M) into which 1,5 naphthalenediol was introduced. Synthesis Example 9 4,4 "methylenebis (dihydroxynaphthalene) 0.
1 mol of epichlorohydrin to 05 mol, to which water was added.
After adding 25 g and 0.8 g of NaOH at 80 ° C. and reacting for 2 hours, unreacted epichlorohydrin was removed at 30 mmHg, and the epoxy was extracted with ether. The ether was distilled off under reduced pressure to obtain an epoxy resin (resin N) having a low introduction rate of 4,4 ″ methylenebis (dihydroxynaphthalene).

Further, a commercially available epoxy resin (manufactured by Dainippon Ink and Chemicals, Inc.) into which 1,6-naphthalenediol is introduced (resin P),
Epoxy resin (made by Dainippon Ink and Chemicals, Inc.) (resin Q) and alicyclic diepoxy CY179 (made by Ciba-Geigy) (resin S) into which commercially available 4,4 "methylene bis (dihydroxynaphthalene) was introduced were prepared.

Further, as a photo-acid generator, triphenylsulfonium triflate (manufactured by Midori Kagaku Co.) (compound 1), 2- (4'-methoxynaphthyl) -4,6-bis (trichloromethyl-1,3, 5-triazine) (Midori Chemical Co., Ltd.)
(Compound m) and nitrobenzylcyclohexylcarbamate (manufactured by Midori Chemical Co., Ltd.) (Compound n) were prepared as a photo-alkali generator.

The compounds as described above were blended according to the formulation shown in Table 3 to obtain photosensitive compositions 18 to 23. That is,
Three times the weight of cyclohexanone or water was added to the solid content of the compounding ratio shown in Table 3, and the mixture was stirred at room temperature for 6 hours, and then filtered through a Teflon filter having a pore size of 0.2 μm to prepare a solution of a photosensitive composition. did.

[0106]

[Table 3]

Each of the photosensitive compositions (solutions) shown in Table 1 was spin-coated on a 5-inch silicon wafer,
Prebaking was performed on a hot plate at 0 ° C. for 5 minutes to form a photosensitive layer (resist film) having a thickness of 0.9 μm.

Then, the photosensitive layer is subjected to pattern exposure (contact exposure) with an ArF excimer laser, and then 1
Baking was performed on a hot plate at 10 ° C. for 2 minutes. Subsequently, the wafer was immersed in the developer shown in Table 4 for 60 to 200 seconds to develop the photosensitive layer. Further, by washing with water and drying, a pattern consisting of predetermined lines and spaces was obtained.

The present embodiment corresponds to the first and second methods . The obtained pattern was observed with a scanning electron microscope (hereinafter abbreviated as SEM) to evaluate the resolution. The results of the sensitivity and resolution (line width of the pattern) of the photosensitive layer (photosensitive composition) in each pattern formation are also shown in Table 4 below.

[0110]

[Table 4]

Further, the absorbance of the 1 μm film thickness at 193 nm of the patterns of the photosensitive compositions 18 to 23 was measured.
The results are shown in Table 5. On the other hand, as Comparative Example 1, the commercially available photoresist OFPR-800 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was also measured for absorbance in the same manner as for the photosensitive compositions 18-23. The results are shown in Table 5.

In Example 2, the photosensitive compositions 18-2
3 and the photoresist OFPR-800 and anti-etching mask pattern obtained using, reactive ion etching (50 m Torr by CF ₄ plasma,
The etching rate at 80 W) was measured. The results are also shown in Table 5.

[0113]

[Table 5]

As described above, the resist of this embodiment is 19
It can be seen that the absorbance at 3 nm is small and the dry etching resistance is excellent. (Example 3) A resin component blended in the photosensitive composition was synthesized. Synthesis Example 10 0.3 mol of trimethylsilyl methacrylate was added to 0.7
Molybdenum glycidyl methacrylate was mixed with 200 g of toluene, 2 g of azoisobutyl nitrile (AIBN) was added, and the mixture was heated at 70 ° C. for 8 hours. Got united. (Molecular weight: 10,000) This was stirred in an acetone-acetic acid-water mixed solvent system for 1 hour, detrimethylsilylated, re-rehydrated with water, and dried to obtain a methacrylic acid-glycidyl methacrylate 3: 7 copolymer. (Resin Q) As another resin component to be blended in the photosensitive composition,
1,5 dihydroxynaphthalene (made by Aldrich)
(Resin R) was prepared.

The above compounds were blended according to the formulation shown in Table 6 to obtain a photosensitive composition 24. That is, three times the weight of cyclohexanone or water was added to the solid content of the compounding ratio shown in Table 6, and the mixture was stirred at room temperature for 6 hours, and then the pore size was 0.2 μm.
m through a Teflon filter to prepare a solution of the photosensitive composition.

[0116]

[Table 6]

Each of the photosensitive compositions 24 (solutions) shown in Table 6 was spin-coated on a 5-inch silicon wafer, and 1
Prebaking was performed on a hot plate at 10 ° C. for 5 minutes to form a photosensitive layer (resist film) having a thickness of 0.9 μm.

Then, the photosensitive layer was subjected to pattern exposure (contact exposure) with the exposure source shown in Table 7, and then 110
Bake for 2 minutes on a hot plate at 0 ° C. Subsequently, the wafer was immersed in the developer shown in Table 7 for 60 to 200 seconds to develop the photosensitive layer. Further, by washing with water and drying, a pattern consisting of predetermined lines and spaces was obtained.

The embodiment corresponds to the first and second methods . The obtained pattern was observed with a scanning electron microscope (hereinafter abbreviated as SEM) to evaluate the resolution. The results of the sensitivity and resolution (line width of the pattern) of the photosensitive layer (photosensitive composition) in each pattern formation are also shown in Table 7 below.

[0120]

[Table 7]

193 of the pattern of the photosensitive composition 24
Absorbance at 1 μm film thickness in nm was measured. The results are shown in Table 8. On the other hand, as a comparative example, a commercially available photoresist OFPR-800 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) is also similarly measured and the absorbance is shown in Table 8.

[0122] In Example 3, a pattern obtained using the photosensitive composition 24 and the photoresist OFPR-800 and anti-etching mask, reactive ion etching by CF ₄ plasma (50 m Torr, 80
The etching rate at the time of W) was measured. The results are also shown in Table 8.

[0123]

[Table 8]

As described above, it is understood that the resist of this example has a small absorbance and an excellent dry etching resistance. (Reference Example 1) Pyrene (a compound that emits fluorescence) corresponding to 3% by weight of the solid content of the photosensitive composition 17 (solution) was added, and the mixture was filtered again to obtain a photosensitive composition 25. did. Using this composition, a pattern was formed according to the same method and conditions as in Example 1. As a developing solution, a 2.38% TMAH aqueous solution was used.

The reference example 1 corresponds to the third method . Table 3 below shows the sensitivity and resolution of the photosensitive layer and the cross-sectional shape of the obtained pattern in Example 4. Table 3 also shows the sensitivity, the resolution (the line width of the pattern), and the cross-sectional shape of the pattern when patterning was performed using the photosensitive composition 17 in Example 1. Reference Example 2 5% by weight of MgWO ₄ powder (a compound that emits fluorescence) and polyacrylic acid were mixed in water, and further 1% of a surfactant Epicoat was added. The obtained dispersion was applied on a substrate and heated at a temperature of 200 ° C. for 5 minutes to form a thin film having a film thickness of 0.1 μm, that is, a fluorescence generating layer. Photosensitive composition 17 (solution) was spin-coated on this thin film, and exposed and developed under the same methods and conditions as in Example 1 to form a pattern. As a developing solution, a 2.38% TMAH aqueous solution was used.

The reference example corresponds to the fourth method. The sensitivity of the photosensitive layer, the resolution (line width of the pattern), and the cross-sectional shape of the pattern in the example are shown in Table 9 below.
Shown in.

[0127]

[Table 9]

* Test Example 1-A pattern was formed using the photosensitive composition 17. Test Example 2 A pattern was formed using the photosensitive composition 25 (a composition containing a compound that emits fluorescence).

Test Example 3 A fluorescence generating layer was formed on a substrate, and a pattern was formed using the photosensitive composition 17 on this layer. Reference Example 3 A photosensitive layer made of the photosensitive composition 17 was formed on the substrate. On this layer, the dispersion liquid of the compound that emits fluorescence used in Example 3 was applied and heated at a temperature of 200 ° C. for 5 minutes to form a thin film having a thickness of 0.1 μm, that is, a fluorescence generation layer. Subsequently, the photosensitive layer and the thin film were exposed to an electron beam of 20 keV and then developed under the same method and conditions as in Example 1 to form a pattern.

In this embodiment, the sensitivity is 5 μC / cm ² ,
A pattern having a line width of 0.3 μm was obtained. For comparison, in the case where the fluorescent layer was not formed on the substrate and the photosensitive layer was directly formed, no pattern could be obtained.

[0131]

As described in detail above, according to the present invention,
It is possible to provide a pattern forming method that employs short-wavelength exposure and that can stably form a pattern having high resolution and excellent dry etching resistance.
The method of the present invention can be effectively applied to photolithography in the manufacturing process of semiconductor devices and the like, and its industrial value is extremely large.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shin Nakase 1 Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Toshiba Research & Development Center Co., Ltd. (56) Reference JP-A-1-207310 (JP, A) Kai 57-78529 (JP, A) JP 5-262874 (JP, A) JP 4-226454 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03F 7 / 00-7/42

Claims (3)

(57) [Claims] 1. A step of forming on a substrate a photosensitive layer containing an aromatic compound having 4 to 12 aromatic rings having conjugated double bonds in its structure, and a wavelength of 1 to the photosensitive layer.
A pattern forming method comprising: a step of pattern-exposing an ultraviolet ray having a wavelength of 80 nm or more and 220 nm or less to cause a photochemical reaction in the photosensitive layer; and a step of developing the photosensitive layer after exposure, which is 4 or more and 12 or less. The aromatic ring having a conjugated double bond of 75% by weight or more and 100% by weight or less of all aromatic rings in the photosensitive layer,
The photosensitive layer uses naphthyl methacrylate as a monomer.
A method of forming a pattern , comprising a copolymer containing the same . 2. A conjugated double structure having 4 or more and 12 or less on a substrate.
Contains an aromatic compound containing an aromatic ring with a bond in its structure
A step of forming a photosensitive layer having a wavelength of 1
Pattern exposure of ultraviolet rays from 80 nm to 220 nm
And causing a photochemical reaction in the photosensitive layer
And a step of developing the photosensitive layer after exposure.
A pattern forming method, in which 4 or more and 12 or less conjugated
The aromatic ring having a double bond is the same for all the aromatic rings in the photosensitive layer.
75% by weight or more and 100% by weight or less of the aromatic ring,
The photosensitive layer is a vinyl compound having an epoxy group as a side chain.
-Containing polymers, vinylated with naphthalene ring in the side chain
Polymer containing compound, polyhydrogen containing naphthalene in the skeleton
Xy compounds and acid or irradiation by irradiation with light or ionizing radiation.
Or containing a compound that generates alkali
Pattern forming method. 3. The wavelength of 180 nm or more and 220 nm or less
Ultraviolet light is ArF excimer laser or YAG laser
Is a light source having a wavelength five times as long as the light source.
The pattern forming method according to claim 1 or 2 .