WO1998049601A1

WO1998049601A1 - Positive resist composition for photomask preparation

Info

Publication number: WO1998049601A1
Application number: PCT/JP1998/001964
Authority: WO
Inventors: Takeyoshi Kato
Original assignee: Nippon Zeon Co., Ltd.
Priority date: 1997-04-30
Filing date: 1998-04-30
Publication date: 1998-11-05

Abstract

A positive resist composition for preparing a photomask, which contains an alkali-soluble phenol resin (A), a quinonediazidesulfonic ester (B) and a solvent (C), characterized in that the solvent (C) contains a linear, branched or cyclic ketone compound (C1) having 6 to 8 carbon atoms; and a process for preparing a photomask by using the positive resist composition.

Description

Technical field of positive resist composition for photomask production>

The present invention relates to a photoresist composition used for producing a photomask, and more particularly to a photomask composition having excellent adhesion to a light-shielding film or an interference film. It relates to a positive resist composition. Further, the present invention relates to a positive resist composition for producing a photomask having excellent adhesion to a light-shielding film or an interference film and excellent storage stability. Further, the present invention relates to a method for producing a photomask using a positive resist composition having such excellent characteristics. Background technology>

A photomask is a component in which a pattern of an electronic circuit is formed of a light-shielding material on a transparent substrate. The photomask is formed on a substrate on which a resist film is formed by a photolithography technique. It is used as a master for selectively irradiating light to the device to project a pattern image of an electronic circuit. Photomasks are used, for example, in the manufacture of semiconductor devices, magnetic bubble memory devices, semiconductor integrated circuits (LSI), liquid crystal displays (LCD), print substrates (PWB), and the like.

In the photolithography technology, a material obtained by dissolving a photosensitive polymer material called a resist in an organic solvent is applied onto a substrate having a layer to be processed formed on a surface thereof. The organic solvent is evaporated in a pre-bake to form a resist film. After partially irradiating the resist film with light, an unnecessary portion of the resist film is dissolved and removed using a developing solution, and the resist pattern is formed on the substrate. To form Next, etching is performed on the resist pattern by immersing it in a solution of an acid or the like that dissolves the layer to be added on the substrate. Finally, remove the unnecessary registry. The photomask is used as an original for partially irradiating the resist film with light.

This photomask is also manufactured using photolithography technology. In the photolithography technology, a notation forming method includes a mask pattern transfer method that irradiates ultraviolet rays, electron beams, X-rays, and the like in a pattern through a photomask. There is a drawing method by beam scanning such as an electronic lion. Although the drawing method is a sequential process, the throughput is low, but the creation and modification of the pattern can be performed quickly and easily, so that the photo mask (including the reticle), This is useful for manufacturing ASICs (Application Spectrified Circuits), etc., or for prototyping devices at the research and development stages.

In many photomask manufacturing processes, a mask pattern is formed using an electron beam lithography system or a laser lithography system. Specifically, a hard mask used for LSI, LCD, PWB and the like and suitable for miniaturization will be described as an example. To manufacture a photomask, first, a light-shielding film made of a thin metal film is formed on a transparent substrate such as a transparent glass plate to form a mask substrate. Chrome is generally used as the metal thin film material. In order to reduce the reflectance of the metal chromium film, there is a two-layer type in which an interference film of a chromium oxide is formed on the metal chromium film. A radiation-sensitive resist film is formed on the light-shielding film or the interference film on the mask substrate. Based on mask pattern data created in advance, an electron beam lithography system or a laser lithography system scans the resist film with an electron beam or laser beam to form a pattern. Forming structure. Next, a resist pattern is formed by developing using a developing solution compatible with the used resist. In this case, development is performed using the difference in solubility or the difference in dissolution rate between the exposed portion and the unexposed portion with respect to the developer. After the development, the light shielding film is etched. Etching of a metal chromium film is mainly performed by etching, and an aqueous solution of ammonium nitrate ammonium is generally used as an etching solution. After the etching, the unnecessary resist film is peeled off. As a result, a photomask in which an electronic circuit pattern (mask turn) formed of a light-shielding film is formed on a transparent substrate can be obtained.

Conventionally, polymers such as polymethyl methacrylate (PMMA) and polymethyl styrene have been known as radiation-sensitive resists used in the drawing method. In this case, an organic solvent is used as a developer. However, PMMA has the disadvantage that it has high resolution but low sensitivity, and also has problems such as deterioration of working environment and difficulty in waste liquid treatment because it uses an organic solvent for the developer. ing.

On the other hand, a positive resist composition in which a soluble phenol resin and a quinone diazide sulfonate-based photosensitizer are dissolved in a solvent has good sensitivity and resolution, and also has an aqueous alkaline composition. Since development with a developer is possible, research and development for use as a resist for photomask manufacturing is underway. However, in general, this positive resist composition has poor adhesion to a metal chromium film (light-shielding film) or a chromium oxide film (thickness film), so that the development step and the etching step For example, there was a problem that the resist film was peeled off. This positive resist composition has poor adhesion especially to a chromium oxide film, but is not suitable for metal chromium oxide. The same is true for the film film because its surface is oxidized to chromium oxide. Invention disclosure>

An object of the present invention is to provide a positive resist composition containing an alkali-soluble phenol resin, a quinone diazide sulfonate, and a solvent, which has excellent adhesion to a light-shielding film or an interference film. An object of the present invention is to provide a positive resist composition for producing a photomask.

Another object of the present invention is to provide a positive resist composition for producing a photomask, which has excellent adhesion to a light-shielding film or an interference film and excellent storage stability.

It is a further object of the present invention to provide a method for producing a photomask using a positive resist composition having such excellent characteristics.

The present inventors have conducted intensive studies to overcome the above-mentioned problems of the prior art, and as a result, have found that a positive electrode containing an alkali-soluble phenol resin, a quinone diazide sulfonate, and a solvent. In the resist composition, a linear, branched or cyclic ketone compound having 6 to 8 carbon atoms may be used alone or in combination with another solvent. Thus, a positive resist capable of forming a resist film having excellent adhesion to a light-shielding film (metal chrome film) and an interference film (chromium oxide film) formed on a photomask substrate. It has been found that a metal composition can be obtained.

In addition, it was found that this positive resist composition exhibited excellent properties immediately after production, but had insufficient storage stability such as precipitation of components when stored for a long period of time. As a result of further study, the specific ketone compound and the lactone compound are used in combination as a solvent. As a result, it has been found that a positive resist composition having excellent adhesion to a light-shielding film or an interference film and excellent storage stability can be obtained. Therefore, this positive resist composition is suitable when long-term storage is required. The present invention has been completed based on these findings.

According to the present invention, there is provided a photoresist for producing a photomask, comprising an alkali-soluble phenol resin (A), a quinone diazide sulfonate (B), and a solvent (C). The solvent (C) contains a linear, branched or cyclic ketone compound having 6 to 8 carbon atoms (C-type positive-type photomask; A resist composition is provided.

Further, according to the present invention, the solvent (C) contains a ketone compound (C and a lactone compound (C.) together with a photoresist type resist composition for producing a photomask. Things are provided.

Further, according to the present invention, a resist film is formed by applying a positive resist composition on the light-shielding film or the interference film of the transparent substrate on which the light-shielding film or the light-shielding film and the interference film are formed. Then, the resist film is irradiated with a radiation beam to draw a pattern, developed with an alkaline developer, and then etched to remove the mask and the pattern. In the method for producing a photomask to be formed, an alkali-soluble phenol resin (A), a quinone diazide sulfonate (B), and a positive resist composition are provided. A linear, branched or cyclic ketone compound containing a solvent (C) and having 6 to 8 carbon atoms (a poly-type resist composition containing C) is used. A method for producing a photomask characterized by this is provided.

In this production method, the solvent (C) is converted into a ketone compound (C and In particular, it preferably contains a lactone compound (c ₂ ). BEST MODE FOR CARRYING OUT THE INVENTION>

(A) Alkali-soluble phenol resin

Examples of the alkali-soluble phenol resin used in the present invention include, for example, condensation reaction products of phenols and aldehydes (novolak resin), phenols Reaction products of phenols and ketones, vinylphenol-based polymers, isopropenylphenol-based polymers, and hydrogenation reaction products of these phenolic resins Things. Of these, novolak resin is particularly preferred.

Specific examples of phenols used in the production of novolak resin include phenol, ο—cresole, m—cresole, and p—cresole. 1, 3, 5 — xylenol, 2, 5 — xylenol, 2, 3 — xylenol, 3, 4 — xylenol, 2, 3, 5 — Tri-methyl phenol, 2, 3 — dimethyl phenol, 2, 5 — dimethyl phenol, 3, 5 — dimethyl phenol Le, 2—Echinoref Enor, 3—Echinoref Enor, 4—Echinoref Enorno, 2—Pro Pinolev Enorno, 3—Propyrno Nor, 4—Propyrヱ Nor, 2, 3, 5 — Tri-Echinolev Enole, 3, 5 — Detjynolev Enole, 2, 5 — Diechinolev Enole, 2 — tert — Butino Phenol, 3-tert-butylphenol, 4-tert-butylphenol, 2-tert-butyl-1-4-methylthiophenol, 2-tert-butylinole-5-methylphenol Monovalent phenols such as eno-nole, 2-phenyl enole, 3-phenyl enole, 4-phenyl enole, etc .; — Methyl resorcinol, 4 — methyl resorcinol, 5 — methyl resorcinol, catechol, 4 — tert-butyl , 3-methoxy alcohol, 2-methoxy resorcinol, 41-methoxy resorcinol, bisphenol A, fluoroglycinol And polyvalent phenols. Each of these phenols can be used alone or in combination of two or more.

Specific examples of aldehydes include formaldehyde, acetate aldehyde, propionaldehyde, n-butyl aldehyde, isobutyl aldehyde, and trimethyl aldehyde. , N—Hexylaldehyde, acrolein, crotonaldehyde, cyclohexanaldehyde, cyclopentanaldehyde, full-color. Aliphatic or cycloaliphatic aldehydes such as furyl crolein; benzaldehyde, o—tolualdehyde, m—tonoraldehyde, p—tolualdehyde, p —Echilbenzaldehyde, 2, 4 — Dimethylbenzaldehyde, 2, 5 — Dimethylbenzaldehyde, 3, 4 1 or 3,5 — Dimethyl norbenzanoledide, phenylase tonanoredeh De, o — hydroxybenzaldehyde, m — hydroxybenzaldehyde, p — hydroxybenzaldehyde, kay skin aldehyde, o — anisaldehyde, m — anisaldehyde, p — anisaldehyde, etc. Aromatic aldehydes; and the like. These aldehydes may be used alone or in combination of two or more. Among these, low molecular weight aliphatic saturated aldehydes such as formaldehyde and acetate aldehyde; o—hydroxy benzyl aldehyde, m—hydroxy benzyl aldehyde, and p—hydroxy benzyl aldehyde, etc. Drokishibenzaldehydes are preferred.

The condensation reaction between phenols and aldehydes can be carried out according to a conventional method. The vinylphenol-based polymer is selected from a homopolymer of vinylphenol and a copolymer of a component copolymerizable with vinylphenol. Specific examples of copolymerizable components include acrylic acid, methacrylic acid, styrene, maleic anhydride, maleic acid imide, vinyl acetate, and acrylonitrile. Examples thereof include lil and derivatives thereof.

Isopropyl vinyl polymer is selected from homopolymers of isopropyl vinyl and copolymers of components copolymerizable with isopropenyl vinyl. You. Specific examples of copolymerizable components include acrylic acid, methacrylic acid, styrene, maleic anhydride, maleic acid imide, vinyl acetate, and acrylic acid. And the like, and derivatives thereof.

The hydrogenation reaction product of the phenolic resin can be produced by any known hydrogenation reaction. Specifically, it can be obtained by dissolving a phenol resin in an organic solvent and introducing hydrogen in the presence of a homogeneous or heterogeneous hydrogenation catalyst.

These alcohol-soluble phenol resins can be used as they are, but may be separated by a known means to control the molecular weight and the molecular weight distribution. As a method of fractionation for the purpose of controlling the molecular weight and molecular weight distribution, the resin is pulverized and extracted one by one with an organic solvent having an appropriate solubility, or the resin is dissolved in a good solvent and dissolved in a poor solvent. Or a poor solvent is dropped to perform solid-liquid or liquid-liquid extraction.

Each of these alcohol soluble resins can be used alone, but if necessary, two or more of them may be used in combination. Further, in the present invention, among these, phenols and aldehydes are obtained by polycondensation in the presence of an acid catalyst. Alkali-soluble phenol resin is preferred. Furthermore, phenolic phenolic resin obtained by polycondensing phenols containing m- and p-cresols with aldehydes is preferred. . This phenolic box resin is a phenol, other than m- and p-cresols, and 3,5-xylenol or phenol. A combination of 2, 3, and 5 trimethylphenol may be used. In addition, the cre- novolak resin has an m-cresol content of 50 mol% or less (usually 5 to 50 mol%, preferably 10 to 45 mol%) in the constituent parts. Mol%) is preferred. If the content of m-cresol is too large, the residual film ratio after development may decrease.

(B) Quinone diazide sulfonate

The quinone diazide sulfonate used in the present invention functions as a photosensitizer. Examples of such quinone diazide sulfonates include 1,2 naphthoquinone diazide-15 sulfonate and 1,2 naphthoquinone diazide-14 sulfonate. Acid ester, 1,2 naphthoquinone diazide 6-sulfonate, 1,2—benzoquinone diazide 5-sulfonate, 1,2-benzoquinone diazide 4- 4-sulfonate And so on. Of these, 1,2 naphthoquinone diazide 5-sulfonate and 1,2 naphthoquinone diazide 4-sulfonate are preferred, and 1,2-naphthoquinone diazide. DO-4 sulfonate is more preferred.

The method for producing these quinonediazidosulfonates is not particularly limited, but quinodiazidosulfonide halides (preferably quinonediazidosulfonate chlorides) are used in accordance with conventional methods. In a solvent such as aceton, dioxane, tetrahydrofuran, etc. Inorganic bases such as aluminum, sodium bicarbonate, sodium hydroxide, and potassium hydroxide, or trimethylamine, tritylamine, trib mouth Pyramine, diisopropylamine, tributylamine, pyrrolidine, pyridin, pyrazine, monolefolin, pyridin, dicyclohexylurea It can be obtained by reacting with polyphenols in the presence of an organic base such as mine.

The polyphenols used herein are those having two or more, preferably three or more, and more preferably four or more phenolic hydroxyl groups in the molecule. It is a droxy compound.

Examples of phenols include 2,3,4-trihydroxybenzophenone, 24,4'-trihydroxybenzobenzonone, and 234-4'-telephenol. Trahydroxybenzofenon, 2 4 2'4 'Tetrahydroxybenzofenon, 23,4,2'4' —Pont of hydroxybenzofenon, etc. Polyhydroxybenzophenones; gallic esters such as methyl gallate, ethyl gallate, and propyl gallate; 22-bis (4-hydroxybenzoyl) pun, 2,2-bis ( 2 4—Polyhydroxybisphenylalkanes such as dihydroxyphenyl) phenyl; tris (4—hydroxyphenyl) methane, 1,1,1,1 tris ( 4-Hydroxy-1 31-Methylphenyl) ethane, 1 1 1—Tris (4ー Hydroxy — 2 — methyl phenyl) ethane, 111 — tris (4 — hydroxyphenyl) ethane, 111 — bis (4 — hydroxy 13 — methyl) 4- (hydroxyphenyl) ethane, bis (4-hydroxy-13-methyl-phenyl) -12-hydroxy 4-phenyloxymethane, etc. Lisphenylalkanes; 1 1, 2,2-tetrakis (4-hydroxyphenyl) ethane, 1,1,2,2—Tetrakis (3—Methenol 14-hydroxyphenyl) Ethan, 1,1,1,3,3—Tetrakis (4—Hi (Drokinphenyl) phenolic alcohols such as prono and phenol; a, a, a ', a'-tetrakis (4-hydroxy) Droxifanil) 1-3 xylene, a, a, a ', a'-Tetrakis (4-hydroxyxeninole) 14-1 xylene HI, a, a ', a'-tetra dry (methyl) 1-4 (hydroxy phenyl) 13-poly (hydroxy) 2,6-bis (2,4-dihydroxybenzil) -r-ρ-cresole, 2,6-bis (2,4-dihydro) Loxy 1 3 — Methynorbenzil) 1 ρ — Cresole, 4, 6 — bis (4-hydroxybenzil) Lesonoresin, 4, 6 — bis (4-hydroxyl 3 — methylbenzil) Zorcin, 4, 6—bis (4—hydroxybenzinole) 1 2—methinole resorcin, 4,6—bis (4—hydroxyl 1 3—methinolepenzinole 2— Trim of phenolic compound such as methyl resorcinol and formalin, the following general formula (I)

(Wherein, shaku ¹ and! ^ ² are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, preferably a hydrogen atom or a methyl group, and R ³ to R ⁶ are mutually independent. And an alkyl group having 1 to 4 carbon atoms, preferably a methyl group.

And a tetramer of a phenol compound and formalin, and a nopolak resin. In the quinonediazide sulfonic acid ester used in the present invention, the ratio (average esterification rate) of the quinonediazidesulfonic acid esterified hydroxyl groups of the hydroxyl groups of these polyphenols is particularly limited. Usually, it is not less than 65%, preferably not less than 70%, expressed as mol% of the quinonediazidesulfonic acid compound relative to the hydroxyl group of polyphenols, The upper limit is usually 100%, preferably 90%. If the ratio of this esterification is too low, the pattern shape and the resolution may be deteriorated.

The quinonediazide sulfonate used as a photosensitizer in the present invention can be used alone or in combination of two or more. The compounding amount of the photosensitizer is usually 1 to 100 parts by weight, preferably 3 to 40 parts by weight, based on 100 parts by weight of the alkali-soluble phenol resin. If the amount is too small, it is difficult to form a pattern. If the amount is too large, the sensitivity is reduced and development residue tends to occur.

(C) Solvent

The positive resist composition for producing a photomask according to the present invention is intended to improve the adhesion to a light-shielding film or an interference film formed on a mask substrate, particularly to a metal chromium film or a chromium oxide film. A linear, branched or cyclic ketone compound having 6 to 8 carbon atoms (C _{ ) is used as a solvent. Further, when the storage stability of the port-shaped record Soo Bok composition is required, Quai tons of compound (C ^ and La click tons compound (c ₂₎ used together with.

The ketone compound (c can be used alone as a solvent, but if necessary, another solvent (c ₃ ) may be used in combination. Preferably, it is at least 50% by weight, based on the total solvent content, and at least 80% by weight. More preferred. Therefore, the compound ij (c) is a ketone compound (c is preferably 50 to 100% by weight, more preferably 80 to 100% by weight, and the other solvent (C ₃ ) preferably comprises 0 to 50% by weight, more preferably 0 to 20% by weight.

When the ketone compound (c) and the lactone compound (C ₂ ) are used in combination, the ratio of the lactone compound (c ₂ ) is preferably based on the total amount of the solvent components. From 1 to 50% by weight, more preferably from 1 to 30% by weight, particularly preferably from 5 to 20% by weight, so that the composition of the solvent (C) is preferably The ketone compound (C 50 to 99% by weight, the lactone compound (C ₂ ) 1 to 50% by weight, and the other solvent (C ₃ ) 0 to 49% by weight are more preferable. Is a ketone compound (C 70 to 99% by weight, a lactone compound (C ₂ ) 1 to 30% by weight, and other solvent (C 3) 0 to 29% by weight. Preferably, the ketone compound (C 80 to 95% by weight, the lactone compound (C.) 5 to 20% by weight, and the other solvent (C ₃ ) 0 to 15% by weight.

If the proportion of the ketone compound (C) in the solvent (C) component is too small, the adhesion to the light-shielding film and the interference film is reduced, and the resist film is peeled off during development and during etching. When the ratio of the lactone compound (c ₂ ) is too small, the etchant is more likely to penetrate between the resist film and the light-shielding film or the interference film. When the storage stability of the positive resist composition is reduced, a large number of fine particles are generated during long-term storage, which become foreign matter on the substrate at the time of drawing, resulting in a mask pattern. When the proportion of each solvent component is within the above range, the balance between adhesion and storage stability becomes good.

Ketone compounds (C is a linear, branched or cyclic C 6-8 Is a ketone compound. Specific examples of such ketone compounds include 2—hexanone, 3—hexanone, 2—heptanone, 3—heptanone, and 4-heptanone. Linear ketones such as 2-octanenon, 3-octanenone, 4-octanenone; 3-methyl 2-pentanonone, 4-methanone Chinore 1 2 — Pentanone, 3 — Etchinore 1 2 — Pentanone, 2,4 -Dimethylinole 3 — Pentannon, 2 — Methyl 3 — Pentanone, 3ー Methyl 2-Hexanone, 5-Methyl 2-Hexanone, 2-Methylenol 3-Hexanone, 4-Methylenol 3-Hexanone, 5-Methyl 1 3- Hexanone, 3 — ethyl 2-, hexanone, 4-ethylinone 2-hexanone, 2, 5 — dimethinol 1 3 — hexanone, 3, 5 — dime Lou 2 — Hexanone, 4, 5 — Dimethyl 2 — Hexanone, 2 — Methyl 3 — Hexanone, 4 — Methyl 3 — Hexanone, 5 — Methyl 3—Hexanone, 2—Ethylone 3—Hexanone, 4—Methyl-3, Hexanone, 5—Methylenol 3—Hexanone, 2—Ethynolane 3—Hexanone, 4-methyl-3—hexanone, 2,4-dimethyl-1,3-hexanone, 2,5—dimethyl-3—hexanone, 4,5—dimethylinole 3—hexanone 2-, methyl 3-, heptanone, 2-, methyl 4-, heptanone, 5-- methyl 3-, heptanone, 6- methyl-2, heptanone, etc. Tones; cyclohexanone, cycloheptanone, cyclohexonone, 2—methylcyclohexane Sanone, 3 — methylcyclohexanone, 4 — methylenocyclohexanone, 2 — ethylenocyclohexanone, 3 — ethylenocyclohexanone, 4 — Etinolesicyclohexanone, 2, 5—Dimethylcyclohexanone, 2, 6—Dimethylcyclohexanone, 3, 4—Dimethylcyclohexanone, 3, 5—Dimethyl Chino-cyclohexanonone, 2-methylcycloheptanone, 3-methylinocycloheptanone, 4-methylinocycloheptanone, 5-methyl Cyclic ketones such as tilcycloheptanone; and the like. Of these, straight-chain ketones are preferred, and straight-chain ketones having 7 carbon atoms, 2—heptanone and 3—heptanone, are more preferred. In particular, 21 heptanones are particularly preferred.

Is a specific example of La click tons (c _2), ₇ - Puchiro la click tons, ₇ - Ba Le b La click tons, 7 - Power Pro la click tons, 7 - Ca pli b La Saturated lactones 7—Lactones; croctactone, single angelica lactone, / 3—unsaturated angelic lactones 7— Lactones; (5—valerolactone, 5—caprolactone, etc. S—lactones; S—propiolactone, 3—butyrolactone Tonto, etc. / S-Lactones; (5-Norolactones, etc. 5-Norrelactones, etc. 5-Lactones; £ 1 Such as lactolactone, ε-oprolactone, etc., etc. Among them, saturated 7—lactons ゃ unsaturated 7—lactos 7-Lactones are preferred, and saturated 7-Lactones are particularly preferred.Saturated 7-Lactones are preferred, and 7-Lactone is preferred. Especially preferred.

Other usable solvents (C ₃ ) include, for example, ketones such as acetone, methylethyl ketone, cyclopentanone, and the like; η—propylanolone, is ο — Propinoleanol alcohol, n — butanol alcohols such as butanol alcohol, cyclohexano alcohol, etc .; ethyl alcohol glycol methyl ether, ethylene glycol alcohol jet alcohol, dioxan Ethers such as ethylene glycol monomethyl ether, ethyl alcohol, etc., etc .; propanol formate, butyl formate, propyl acetate, butyl acetate, propionate Esters such as methyl acetate, ethyl propionate, methyl butyrate, ethyl butyrate, methyl lactate, and ethyl lactate Cerro Sorupuasete one door, Celloso-nolebutesters such as methino-cello-sonoacetate, ethylcello-sono-rube-acetate, propylcello-sol-ve-acetate, butyl cello-so-nore-acetate; propylene glycol and propylene glycol Lenglycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monobutyl ether Which propylene glycols; diethyl glycol, non-methylone, diethylene glycol, non-ethylone, diethylene glycol, non-ethylene, diethylene, diethylene glycolジェ, ジェ, ジェ, ジ, ジ, 、 Diethylene glycols such as methyl ethyl ether; halogenated hydrocarbons such as trichloroethylene; aromatic hydrocarbons such as toluene and xylene; Polar solvents such as dimethyl acetate amide, dimethyl formamide, N-methyl acetate amide; and the like. Each of these solvent components can be used alone or in combination of two or more. The amount of the solvent (C) used is sufficient to uniformly dissolve each component other than the solvent.

(D) phenolic compound

In the present invention, a phenol compound can be added for the purpose of improving the sensitivity of the positive resist composition. Specific examples of such phenolic compounds include phenols disclosed in WO96 / 22563 and a, a'-monosubstituted phenols. A resin obtained by condensing xylens with an acid catalyst, or a resin obtained by condensing phenols with dicyclopentadiene in the presence of an acid catalyst. Resin-based phenols such as obtained resins; p-vinyl phenol, p-isophenol phenol, etc .; phenol; biphenol , 4,4 '— Hydroxy dino-tinole, 4,4'-Dihydroquinone zof Bisphenol A (manufactured by Honshu Chemical Industry Co., Ltd.), Bisphenol C (manufactured by Honshu Chemical Industry Co., Ltd.), Bisphenol E (manufactured by Honshu Chemical Industry Co., Ltd.), bisphenolノ Knore F (Honshu Chemical Co., Ltd.), Bisphenol AP (Honshu Chemical Co., Ltd.), Bisphenol M (Mitsui Petrochemical Co., Ltd.), Bisphenol P (manufactured by Mitsui Petrochemical Industries, Ltd.), bisphenol Z (manufactured by Honshu Chemical Industries), 1, 1-bis (4—hydroxy phenol) 9, 9—bis (4—hydroxyphenyl) fluorene, 1,1bis (5—methyl-2—hydroxyphenyl) methane, 3,5—dimethinolelate 4 — Bisphenols such as hydroxybenzinolephenol; 1,1,1-tris (4-hydroxyphenyl) ) Methane, 1, 1, 1 1 tris (4-hydroxy phenyl) ethane, 1, 1 — bis (3 — methino 1 4 — hydroxy) Nil) 1 1 — (4-Hydroxyphenyl) methane, 1, 1 bis (2, 5 — dimethyl 4 — Hydroxyphenyl) 1 1 — (2 —Hydroxyphenyl) methane, 1,1-bis (3,5—Dimethyl-1-4-hydroxyphenyl) 1-1— (2-Hydroxyphenyl) Phenyl) methane, 2, 6-bis (5—methyl 1 2—hydroxybenzoyl) 1 4—methinolephen, 2, 6—bis (4—hydroxy) 4-Methylphenol, 2, 6-bis (3-methyl-14-hydroxybenzoyl) 1-4-methylphenol, 2,6-bis (3,5) — The Chill-14-Hydroxybenzene-14-Methylphenol, Trisphenol-PA (manufactured by Honshu Chemical Industry Co., Ltd.), Trisphenol-TC Trisphenols such as Honshu Chemical Industry Co., Ltd .; 1, 1, 2, 2—tetrakis (4—hydroxyphenyl) ethane, 1, 1, 2,2—Tetrakis (3—Methyl-1-Hydroxyphenyl) ethane, 1,1,3—, 3— (4—Hydroxyphenyl) Prono, ⁰ , 1, 1, 5, 5 — Tetrakis (4 — Hydroxyphenyl) Pentane, hi, a., A ', a' — Tetrakis (4-hydroxyphen) 1 3 — xylen, hi, a, a ', a' Trakis (4—Hydroxy-Ninyl-14-xylene, a, a, a ', a'—Tetrakis (3-Methyl-1-Hydroxyphenyl) 1-3 —Xylene, hi, a, a ', a'-Tetrakis (3—Methyl-14—Hydroxyphenyl) —4—Tetrakisphenols such as xylene Among these, trisphenols and tetrakisphenols are particularly preferred examples.

The amount of these phenolic compounds varies depending on the composition, molecular weight, molecular weight distribution, and type and amount of other additives of the soluble polyphenol resin. 1 The upper limit is usually 50 parts by weight, preferably 30 parts by weight, more preferably 20 parts by weight, and the lower limit is usually 100 parts by weight based on 100 parts by weight of the resin. Parts by weight, preferably 2 parts by weight, more preferably 3 parts by weight.

The positive resist composition of the present invention optionally contains a surfactant, a storage stabilizer, a sensitizer, a striation inhibitor, a plasticizer, and other additives as necessary. It can be done.

(E) Developer

The positive resist composition of the present invention can be developed with an alkaline developer. As the alkaline developer, an aqueous inorganic alkaline solution, that is, an aqueous solution of an alkaline inorganic compound is preferable. Specifically, for example, aqueous solutions of inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium gayate, ammonia, mixtures thereof, and pH buffers Agents, surfactants, and compatible low-grade alcohols. As the alkali developer, an organic developer such as ethanolamine may be used, if necessary. It can also be.

(F) Photomask manufacturing method

In the present invention, a photomask is prepared by a photolithography technique using the positive resist composition. To manufacture a photomask, first, a light-shielding film or a light-shielding film and an interference film are formed on a transparent substrate to form a mask substrate. Usually, a transparent glass plate is used as the transparent substrate. Chrome is used as a material for forming the light-shielding film. Alternatively, silicon, iron oxide, molybdenum sulfide, or the like may be used. The interference film serves to reduce the reflectance of the light-shielding film, and usually uses chromium oxide, and is formed as a chromium oxide film on the surface of a metal chromium film (two-layer type). . A three-layer type in which the interference film is also provided on the back surface of the metal chromium film can be used.

Next, a positive resist composition is applied on the light-shielding film or the interference film of the mask substrate to form a resist film. Coating, drying, prebaking and the like of the positive resist composition can be carried out according to a conventional method. Next, the resist film is irradiated with a radiation beam to draw a pattern. Usually, an electron beam lithography system and a laser lithography system are used for writing with a radiation beam, and an electron beam or a laser beam is scanned based on a mask pattern, and the resist film is formed on the resist film. The pattern is drawn. After the drawing step, development is carried out by an ordinary method such as immersion development using an alkaline developer. In this way, a resist pattern is formed. After development, post baking or desmating (surface treatment with oxygen plasma or the like) can be performed if necessary.

After the development process, the light-shielding film is etched. Etching is a step of transferring the resist pattern formed by the resist pattern forming method to the underlying light-shielding film or the light-shielding film and the interference film. Etchin There are two types of driving methods: jet etching using a liquid, and dry etching using a gas.ゥ Etching is generally performed using ammonium cerium nitrate (Kodak specification). Etching is performed by dipping or spraying. As the dry etching gas, a carbon halide gas such as carbon tetrachloride or a chlorine-based gas is used.

After the etching step, the resist film is peeled off. The resist film can be removed by a chemical method using an acid obtained by adding hydrogen peroxide or ozone to an organic solvent or concentrated sulfuric acid, or a physical method using an oxygen plasma or a UV-ozone-assisting treatment. . A combination of chemical and physical methods can be applied. Thereby, a photomask on which the mask pattern of the light-shielding film is formed can be obtained. The photomask may be a reticle (a mask for a reduction exposure apparatus). Example>

Hereinafter, the present invention will be described more specifically with reference to Synthesis Examples, Examples, and Comparative Examples. Parts and percentages are by weight unless otherwise specified. The method for evaluating the resist characteristics is as follows.

(1) Peeling of resist film during development

After the development, the substrate surface was observed with an optical microscope, and the presence or absence of peeling of the line pattern of the resist film was observed. The adhesion was evaluated according to the following criteria.

◎: No peeling at all

〇: There is peeling in only a part, but it is within the acceptable range.

△: Partial peeling is observed,

X: Extensive or numerous peeling. (2) Side etch amount

After etching, the cross section of the pattern was observed with a scanning electron microscope to determine the extent of penetration of the etching solution into the interface between the resist film and the chromium oxide film (side etch amount). It was measured. The smaller the side etch amount, the greater the adhesion of the resist film.

(3) Storage stability

Immediately after the preparation of the resist solution, and after sealing a portion of the resist solution in a washed sample bottle and storing it at 23 ° C for 3 months, the Lyon Parties were used. The number of microparticles was measured by Kurkaunter-1 "KL-20A".

[Synthesis example 1]

Synthesis of novolak resin

Two liter flasks equipped with a cooling tube and stirrer were fitted with m-cresole 310 g, p-cresol 466.6 g, 36% formalin 39 94 g, and 2.45 g of oxalic acid dihydrate were added, and the mixture was reacted for 35 minutes while maintaining the temperature at 95 to 100 ° C. After that, water was distilled off at 100 ° C over a period of 100 minutes at 105 ° C, and then the pressure was reduced to 10 mmHg while the temperature was raised to 170 ° C. The temperature was continuously raised to 190 ° C to remove unreacted monomers and residual water. Thereafter, the generated molten resin was returned to room temperature to obtain 544 g of a novolak resin. The weight of this novolak resin in terms of polystyrene using tetrahydrofuran is determined by Geno-Hermi-Minion's Chromatography. When the average molecular weight (Mw) was measured, it was 50,000.

[Synthesis example 2]

Synthesis of quinone diazide sulfonate eztel

Polyphenols are 2,3,4,4'-tetrahydroxybe Using 1,2-naphthoquinonediazide-14-sulfonate chloride in dioxane, an amount corresponding to 87.5 mol% of this hydroxyl group was obtained using benzophenone. And dissolved in a solution to make a 10% solution. While controlling the temperature to 250 ° C, 12-naphthoquinone diazide 4 — 1.2 equivalents of sulfonic acid chloride was added for 30 minutes. Then, the reaction was completed by maintaining the reaction temperature for 2 hours. The precipitated salt was separated by filtration and poured into a 10% equivalent of a 0.2% aqueous solution of oxalic acid of the reaction solution. The precipitated solid was filtered, washed with ion-exchanged water, and dried to obtain quinone diazide sulfonate.

[Example 13 and Comparative Example 13]

100 parts by weight of the novolak resin obtained in Synthesis Example 12 above and 25 parts by weight of quinone diazide sulfonate were added to Honshu Chemical Co., Ltd. as a phenol compound. Li staple We Roh Lumpur PA "[compound name: 2 - (4 - (1, 1 one bis (4 - arsenate de Rokishifu Weniru) Echiru) off Weniru) - 2 - (4 - human Dorokishi off We sulfonyl) flop ⁰ 15 parts by weight are dissolved in the solvents listed in Table 1 and filtered through a 0.1-pore-size polytetrafluoroethylene (PTFE) membrane filter to form a poly-register. A composition (resist solution) was prepared.

This resist solution was spin-coated on a silicon wafer coated with 800-ounce-thick chromium oxide, and then heated on a 110 ° C hot plate. Then, the resist film was baked for 90 seconds to form a resist film having a thickness of 50,000 angstroms. Next, an acceleration voltage of 20 kV was applied to the resist film formed on the silicon wafer using an electron beam lithography system ELS-3300 (a pencil beam type manufactured by Elionix Inc.). Irradiation was performed at an energy of 9 〃 C / cm ² , and 11 lines with a line width of 10 11 and a space of ⁰ lines were drawn. After drawing the pattern, develop it by applying it to a 1.0% aqueous solution of potassium hydroxide at 23 ° for 60 seconds, rinse it with pure water, and wash it with a positive pattern with a line width of 10 m. I got it. After the formation of the pattern, etching was performed by immersing in an etching solution in which 5.0% perchloric acid and ammonium nitrate ammonium were dissolved in water at 23 ° C for 30 seconds. Table 1 shows the evaluation results. In these examples and comparative examples, a silicon wafer was used as the substrate from the viewpoint of operation and evaluation. However, similar results can be obtained by using a glass substrate. table 1

[Examples 4 to 6, Reference Examples 1 and 2]

A resist solution was prepared and a pattern was formed in the same manner as in Examples 1 to 3, except that the solvent was changed to the solvent shown in Table 2. Table 2 shows the results. O 98/49601

24 Table 2

[Example 7]

A 500-Å-thick metal chromium film is formed on a square glass substrate (commonly called 409), and a 300- A chromium oxide film was formed to create a two-layer mask substrate. After spin-coating the resist solution prepared in Example 5 on the chromium oxide film of the mask substrate, the solution was heated for 90 seconds on a hot plate at 110 ° C. As a result, a resist film having a thickness of 5,000 Å was formed. Drawing was performed on this resist film in the same manner as in Examples 1 to 3. Further, development and etching were performed in the same manner as in Examples 1 to 3. Then, the substrate was immersed in N-methylpyrrolidone at 35 ° C for 180 seconds, rinsed with pure water, and the resist film was peeled off. In this way, a photomask was created.

The resulting photomask has no resist film peeling during development, and has a side-etching (amount of side-etching) at the time of wet-etching. = 220 ngstrom), and it was confirmed that the dimensional fluctuations were suppressed to a small extent and the yield was greatly improved. Industrial applicability>

According to the present invention, there is provided a positive resist composition containing an alkali-soluble phenol resin, a quinone diazide sulfonic acid ester, and a solvent, which has an adhesive property with a light-shielding film or an interference film. An excellent positive resist composition for producing a photomask is provided. Further, according to the present invention, there is provided a positive resist composition for producing a photomask, which has excellent adhesion to a light-shielding film or an interference film and excellent storage stability.

The positive resist composition for producing a photomask of the present invention not only has excellent resist characteristics such as sensitivity, resolution, pattern cross-sectional shape, and remaining film ratio, particularly in an electron beam lithography method, Because of its excellent adhesion to the light-shielding film and the interference film, peeling and side-etching of the resist film in the developing step and the etching step are suppressed. Furthermore, the positive resist composition of the present invention has excellent storage stability, and can be mass-produced. In addition, since an aqueous inorganic developer can be used, there is no problem of deteriorating the working environment due to evaporation of the organic solvent, and waste liquid treatment is easy.

Claims

The scope of the claims

1. Posi-type resist composition for photomask production, containing alkaline soluble phenolic resin (A), quinone diazide sulfonate (B), and solvent (C) Solvent, wherein the solvent (C) contains a linear, branched or cyclic ketone compound having 6 to 8 carbon atoms (C-type polyketone resin for photomask production). Dist composition.

2. a solvent (C), Quai tons compound (C and the monitor, La click tons of compound (c ₂₎ containing claim 1 off O masks for producing positive Les Soo DOO composition according .

3. The photomask production method according to claim 1 or 2, wherein the solvent (C) contains at least 50% by weight of a ketone compound (C) based on the total amount of the solvent components. Positive resist composition.

4. Solvent (C) is referenced to the total solvent component amount, 1-5 0% by weight of Lac Bok emission compound (C ₂₎ according to claim 2, wherein full O mask manufacturing Po di type record containing Dist composition.

5. 50 to 99% by weight of ketone compound (C and 1 to 50% by weight of lactone compound (C ₂ ), based on the solvent (C) power and the total amount of solvent components The positive resist composition for producing a photomask according to claim 4, comprising:

6. Solvent (C) is 70-99 times based on the total amount of solvent components The amount% of Ke tons compound (C and 1-3 0% by weight of La click Bok emission compound (C ₂₎ according to claim 5 off O mask producing positive registry composition according containing.

7. The positive resist composition for producing a photomask according to claim 1, wherein the ketone compound (C is a straight-chain ketone compound having 7 carbon atoms).

8. The positive resist composition for producing a photomask according to claim 7, wherein the linear ketone compound having 7 carbon atoms is 2-heptanone.

9. The positive resist composition for producing a photomask according to claim 2, which is a lactone compound (C ₂ ) or a saturated lactone.

10. The positive resist composition for photomask production according to claim 9, wherein the saturated 7-lactone is 7-ptyrolactone.

11. The photomass according to claim 1 or 2, wherein the alkali-soluble resin (A) is a novolak resin obtained by polycondensing phenols and aldehydes. Positive-type resist composition for producing a paste.

1 2. Cresanol obtained by the polycondensation of alkanol soluble resin (A) with phenols containing m-cresol and p-cresol and aldehydes. The positive resist composition for producing a photomask according to claim 11, which is a box resin.

13. The quinone diazide sulfonate (B) is a 1,2-naphthoquinone diazide 4—sulfonate ester of polyphenols. Or the positive resist composition for producing a photomask according to 2.

14. The positive resist composition for producing a photomask according to claim 1 or 2, further comprising a phenol compound (D).

15. Dissolve uniformly 1 to 100 parts by weight of quinondiazide sulfonate (B) and 100 parts by weight of alkali soluble resin (A) to 100 parts by weight. 3. The positive resist composition for producing a photomask according to claim 1, which contains a sufficient amount of the solvent (C).

16. Claim 1 further containing 1 to 50 parts by weight of a phenol compound (D) based on 100 parts by weight of an alkali-soluble phenol resin (A). 6. The positive resist composition for photomask production according to 5.

17. A positive resist composition is applied to the light-shielding film or the interference film on the transparent substrate on which the light-shielding film or the light-shielding film and the interference film are formed to form a resist film, and then the resist film is formed. A method for manufacturing a photomask in which a pattern is drawn by irradiating a film with a radiation beam, developed with an alkaline developer, and then etched to form a mask pattern. Wherein the positive resist composition comprises an alkali-soluble phenol resin (A), a quinone diazide sulfonate (B), and a solvent (C), and a solvent. (C) is a positive-type resist group containing a linear, branched or cyclic ketone compound (C _{ ) having 6 to 8 carbon atoms. A method for producing a photomask, which comprises using a composition.

1 8. Solvent (C) is, Ke tons compound (C and the monitor, Lac tons compound (C ₂₎ off O mask manufacturing method according to claim 1 7, wherein the containing.

19. The method for manufacturing a photomask according to claim 17, wherein the light-shielding film or the interference film is a metal chromium film or a chromium oxide film.

20. The method for producing a photomask according to claim 17 or 18, wherein the radiation beam is an electron beam or a laser beam.