CN118732397A

CN118732397A - Positive photoresist composition and method for producing resist pattern

Info

Publication number: CN118732397A
Application number: CN202310311530.7A
Authority: CN
Inventors: 钱彬; 周晓龙; 王孟雪
Original assignee: Changzhou Qiangli Photoelectric Material Co ltd; Changzhou Tronly New Electronic Materials Co Ltd; Changzhou Tronly Advanced Electronic Materials Co Ltd
Current assignee: Changzhou Qiangli Photoelectric Material Co ltd; Changzhou Tronly New Electronic Materials Co Ltd; Changzhou Tronly Advanced Electronic Materials Co Ltd
Priority date: 2023-03-28
Filing date: 2023-03-28
Publication date: 2024-10-01

Abstract

A positive photoresist composition for producing LCD, which comprises an integrated circuit and a liquid crystal display part formed on a substrate, wherein the composition comprises (A) an alkali-soluble resin, (B) a diazonaphthoquinone sulfonate, (C) a phenolic hydroxyl compound having a molecular weight of 1000 or less, and (D) an organic solvent, and the component (B) comprises the reaction product of a polyhydric phenol compound represented by the following general formula (I) and (II) a diazonaphthoquinone sulfonyl chloride compound. The present invention can provide a positive photoresist composition suitable for system LCD manufacture, which can satisfy both high sensitivity and high residual film rate, and a method for forming a resist pattern.

Description

Positive photoresist composition and method for producing resist pattern

Technical Field

The present invention relates to a positive photoresist composition for manufacturing an integrated circuit or a Liquid Crystal Display (LCD) and a method of forming a resist pattern using the positive photoresist composition.

Background

Photoresists, also known as photoresists, are important materials in the manufacture of integrated circuits or liquid crystal panels (LCDs) and are used as corrosion resistant coating materials in photolithography processes. As the line width of integrated circuits has been gradually reduced with the development of photolithography, the exposure wavelength of photoresist has undergone a process ranging from G line (436 nm), I line (365 nm), to deep ultraviolet (KrF 248 nm), the composition of positive photoresist compositions used for integrated circuit fabrication or liquid crystal panel (LCD) production has also been continuously changed, alkali-soluble resins (e.g., novolac resins) are included, and ultraviolet positive photoresists containing diazonaphthoquinone compounds are the most used photoresists in G line lithography, I line lithography. In one aspect, the phenolic resin is soluble in an alkaline developer and does not swell in the developer. On the other hand, diazonaphthoquinone photosensitizers are converted to indene carboxylic acids upon exposure to increase the solubility of the phenolic resin, while they crosslink with the phenolic resin in the non-exposed areas to act as dissolution inhibitors. Phenolic resin/diazonaphthoquinone systems are widely used because of the above advantages.

Heretofore, photoresist compositions containing diazonaphthoquinone-type photosensitizer-phenolic resins have been widely reported.

In IBM corporation, U.S. patent GB1501194a, a positive photoresist composition is reported which contains diazonaphthoquinone sulfonate of 2,3, 4-trihydroxybenzophenone and phenolic resin components, which can be used to manufacture semiconductor devices. Photoresists containing this type of photosensitizer have problems in terms of resolution and pattern shape (profile).

In Japanese Mitsubishi chemical corporation, JP1992001340B2, a positive photoresist composition containing 2,3, 4' -tetrahydroxybenzophenone diazonaphthoquinone sulfonate and a phenolic resin prepared from a mixture of p-cresol and 2, 5-xylenol is disclosed. The positive photoresist exhibits good resolution (up to 1.0 μm) and good thermal stability. The solubility of the 2,3, 4' -tetrahydroxybenzophenone diazonaphthoquinone sulfonate in the photoresist formulation is very low, and the aim of improving the sensitivity of the photoresist cannot be achieved by increasing the addition amount of the sulfonate.

In Japanese Sumitomo chemical Co., ltd., JP1991007240A, a positive photoresist composition containing 2-hydroxyphenyl-2-trihydroxyphenyl propane diazonaphthoquinone ester is reported. Compared with positive photoresist containing diphenyl ketone compound, the resolution is higher and can reach 0.5-0.6 mu m. However, the positive photoresist in this patent has obvious defects in terms of thermal stability and cannot be applied to a dry etching process.

Summary of The Invention

In view of the shortcomings of the prior art, it is an object of the present invention to provide a positive photoresist composition for manufacturing an integrated circuit or a Liquid Crystal Display (LCD) having excellent performance of high film residue rate while satisfying high sensitivity required for manufacturing a system LCD having an integrated circuit and a liquid crystal display portion, and a method of forming a resist pattern.

The above object can be achieved by the following aspects of the present invention.

The present invention provides a positive photoresist composition for manufacturing an integrated circuit or a Liquid Crystal Display (LCD), which is characterized in that: comprises (A) an alkali-soluble resin, (B) a diazonaphthoquinone sulfonate, (C) a phenolic hydroxyl-containing compound having a molecular weight of 1000 or less, and (D) an organic solvent, wherein the component (B) comprises a reaction product of a polyhydric phenol compound represented by the following general formula (I) and a diazonaphthoquinone sulfonyl chloride represented by the following general formula (II),

Wherein each R ₁、R₂、R₃ independently represents hydrogen, halogen, C ₁～C₁₈ straight or branched alkyl, C ₆～C₁₂ aryl, C ₁～C₈ alkoxy, C ₁～C₈ alkylthio, C ₂～C₁₀ unsaturated hydrocarbon group, C ₃～C₁₂ cycloalkyl, C ₄～C₁₂ cycloalkylalkyl, C ₁～C₉ alkanoyl, C ₇～C₁₃ aroyl, C ₃～C₆ heterocyclyl wherein a carbon or hydrogen atom may be optionally substituted by O, S or an N atom, C ₁～C₁₈ alkylamino or arylamino; a. b and c each independently represent an integer of 0 to 2; x, y, z each independently represent an integer between 0 and 3; the diazonaphthoquinone sulfonyl chloride (II) is one of the following structural compounds.

In addition, the present invention also provides a method for forming a resist pattern, comprising the steps of: (1) A step of forming a coating film by coating the positive photoresist composition on a substrate; (2) A step of forming a resist film on a substrate by performing a heat treatment (pre-baking) on the substrate on which the coating film is formed; (3) A step of selectively exposing the resist film using a mask on which both a resist pattern forming mask pattern of 2.0 [ mu ] m or less and a resist pattern forming mask pattern of more than 2.0 [ mu ] m are drawn; (4) A step of performing a heat treatment (post-exposure baking) on the selectively exposed resist film; (5)

And a step of simultaneously forming a resist pattern for an integrated circuit having a pattern size of 2.0 [ mu ] m or less and a resist pattern for a liquid crystal panel (LCD) having a pattern size of more than 2.0 [ mu ] m on the substrate by subjecting the resist film after the heat treatment (post-exposure baking) to a development treatment with an aqueous alkali solution.

Detailed Description

The inventors have surprisingly found that the positive photoresist composition used in the present invention can have particularly excellent performance when used in the manufacture of liquid crystal panels (LCDs) or integrated circuits, has good compatibility of each component, has excellent photosensitivity, and has good developability, and the produced resist pattern has high residual film rate.

Positive photoresist composition for LCD manufacture

Component (A)

(A) The component is an alkali-soluble resin.

The component (a) is not particularly limited, and 1 or 2 or more kinds of components can be arbitrarily selected from those usually used as a coating film in a positive photoresist composition.

Examples include: novolac resins obtained by condensing phenols (phenol, m-cresol, p-cresol, xylenol, trimethylphenol, etc.) and aldehydes (formaldehyde, formaldehyde precursor, propionaldehyde, 2-hydroxybenzaldehyde, 3-hydroxybenzaldehyde, 4-hydroxybenzaldehyde, etc.) in the presence of an acidic catalyst;

Hydroxystyrene homopolymers, copolymers of hydroxystyrene and other styrene monomers, and copolymers of hydroxystyrene and acrylic acid or methacrylic acid or derivatives thereof;

And acrylic or methacrylic resins which are copolymers of acrylic acid or methacrylic acid and derivatives thereof.

In order to obtain a resist material having high sensitivity and good resolution, a novolak resin obtained by condensing phenols and aldehydes in the presence of an acidic catalyst is preferable, and a novolak resin obtained by a condensation reaction of phenols containing at least 2 species selected from m-cresol, p-cresol, 3, 4-xylenol or 2,3, 5-trimethylphenol and aldehydes containing formaldehyde is particularly preferable.

The novolak resin may be produced by a conventional method or commercially available.

The weight average molecular weight of the novolak resin is preferably 2000 to 100000, more preferably 2000 to 30000, from the viewpoints of sensitivity and pattern formation.

Component (B)

(B) The component (C) is diazonaphthoquinone sulfonate, which contains a specific non-benzophenone PAC, namely, a reaction product of the polyhydric phenol compound represented by the general formula (I) and the diazonaphthoquinone sulfonyl chloride (II) (hereinafter referred to as a photosensitizer). The positive photoresist composition containing the photosensitizer has high sensitivity, high resolution and high residual film rate. And is suitable for i-line lithography, which is also desirable in terms of characteristics such as linearity, depth of focus (DOF), etc.

The polyhydric phenol compound has a structure shown in the following formula (I):

Wherein each R ₁、R₂、R₃ independently represents hydrogen, halogen, C ₁～C₁₈ straight or branched alkyl, C ₆～C₁₂ aryl, C ₁～C₈ alkoxy, C ₁～C₈ alkylthio, C ₂～C₁₀ unsaturated hydrocarbon group, C ₃～C₁₂ cycloalkyl, C ₄～C₁₂ cycloalkylalkyl, C ₁～C₉ alkanoyl, C ₇～C₁₃ aroyl, C ₃～C₆ heterocyclyl wherein a carbon or hydrogen atom may be optionally substituted by O, S or an N atom, C ₁～C₁₈ alkylamino or arylamino; a. b, c each independently represent an integer between 0 and 2, such as 0, 1 or 2; x, y, z each independently represent an integer between 0 and 3, such as 0, 1,2 or 3.

By applying the technical scheme provided by the application, the diazonaphthoquinone sulfonate prepared by taking the polyhydroxy phenol compound as an intermediate is applied to a photoresist composition as a photosensitizer, and the obtained photoresist has clear resolution and high sensitivity, also has excellent thermal stability and etching resistance, and has wide application prospect in the field of semiconductors.

In some embodiments of the present application, when R ₁、R₂、R₃ each independently represents hydrogen, C ₁～C₆ straight or branched alkyl, C ₆～C₁₂ aryl, C ₁～C₆ alkoxy, the diazonaphthoquinone sulfonate prepared by using the polyhydroxy phenol compound as an intermediate is used as a photosensitizer in a photoresist composition, and the resulting photoresist has more excellent resolution, photosensitivity, thermal stability and etching resistance.

In some embodiments of the present application, the polyhydric phenol compound is selected from at least one of the following structural compounds:

the diazonaphthoquinone sulfonate prepared by taking the polyhydroxy phenol compound (I) with the structure as an intermediate is applied to a photoresist composition as a photosensitizer, and the obtained photoresist has better performance, better resolution, photosensitivity, thermal stability and etching resistance.

The polyhydric phenol with the structure can be used in combination of 1 or more than 2 after diazonaphthoquinone esterification.

The method for diazo naphthoquinone esterification of phenolic hydroxyl groups of a compound represented by the general formula (I) is as follows:

The preparation method comprises the following steps: and A1, mixing a polyhydroxy phenol compound represented by a general formula (I) and diazonaphthoquinone sulfonyl chloride (II) in an organic solvent, and reacting under the action of an acid binding agent to obtain the diazonaphthoquinone acid ester product.

The reaction is carried out under the protection of inert gases including but not limited to nitrogen or argon; the reaction temperature is 20-60 ℃, the reaction time is 0.5-6 h, especially when the reaction temperature is 25-40 ℃, the reaction time is 1-3 h, which is more beneficial to improving the preparation efficiency of the diazonium quinone sulfonate.

The type of the acid-binding agent is not limited, and any substance capable of promoting the reaction of the polyhydric phenol compound represented by the general formula (I) with the diazonaphthoquinone sulfonyl chloride (II) may be used, including but not limited to at least one of triethylamine, tripropylamine, ethylenediamine, pyridine, 4-dimethylaminopyridine, quinoline, N-dimethylaniline, tetramethylammonium hydroxide, sodium methoxide, sodium ethoxide, potassium t-butoxide, lithium diisopropylamide, sodium carbonate, sodium hydrogencarbonate, sodium hydroxide, potassium carbonate, potassium hydrogencarbonate, potassium hydroxide, ammonium hydroxide, sodium hydride, preferably a mixture of one or more of triethylamine, pyridine, sodium hydrogencarbonate.

The type of the above organic solvent is not limited, and any substance capable of promoting the reaction of the polyhydric phenol compound represented by the general formula (I) with the diazonaphthoquinone sulfonyl chloride (II) may be used, including, but not limited to, methanol, ethanol, benzene, toluene, methylene chloride, ethylene dichloride, acetone, butanone, tetrahydrofuran, o-xylene, m-xylene, N-dimethylformamide, tetrahydrofuran, ethyl acetate, 1, 4-dioxane, pyridine, N-methylpyrrolidone, or a mixture of one or more thereof.

Step A2, purifying the diazonaphthoquinone sulfonate product to obtain diazonaphthoquinone sulfonate; wherein the polyhydric phenol compound is the polyhydric phenol compound provided in the first exemplary embodiment described above or the polyhydric phenol compound obtained by the production method provided in accordance with the second exemplary embodiment, and the diazonium sulfonyl chloride (II) represents at least one of the following structural compounds.

In the step A2, the purification comprises at least one of solid-liquid separation, crystallization, washing and drying;

the crystallization step is preferably carried out in dilute hydrochloric acid, and the mass concentration of the dilute hydrochloric acid is 0.1-5.0%, preferably 0.5-2.0%.

In order to further increase the drying efficiency, it is preferable to carry out the drying under reduced pressure at a pressure of 10 to 500mbar and a temperature of 40 to 60 ℃.

Typically, but not by way of limitation, the temperature of the reaction in the preparation of diazonaphthoquinone sulfonate (B) is, for example, 20 ℃,25 ℃,30 ℃, 35 ℃, 40 ℃, 45 ℃,50 ℃, 55 ℃, 60 ℃ or a range between any two values; the reaction time is, for example, 1h, 1.5h, 2h, 2.5h, 3h or a range value between any two values; the mass concentration of the diluted hydrochloric acid used for crystallization is, for example, 0.1%, 0.2%, 0.5%, 0.8%, 1%, 1.5%, 2%, 3%, 4%, 5% or a range value consisting of any two values; the drying pressure is, for example, 10mbar, 20mbar, 50mbar, 100mbar, 150mbar, 200mbar, 300mbar, 400mbar, 500mbar or a range of values consisting of any two; the drying temperature is, for example, 40 ℃, 42 ℃, 45 ℃, 48 ℃,50 ℃, 52 ℃, 55 ℃, 58 ℃, 60 ℃ or a range of values consisting of any two values.

In some embodiments of the application, the diazonaphthoquinone sulfonate is prepared as follows:

(1) Uniformly mixing a second organic solvent, a polyhydroxy phenol compound and DNQ in an inert gas protective atmosphere;

(2) Slowly adding an acid binding agent under the room temperature condition, heating to the reaction temperature, and keeping the temperature for continuous reaction;

(3) After the reaction in the step (2) is finished, filtering for the first time to remove solid precipitated in the system, slowly adding mother liquor obtained after filtering into dilute hydrochloric acid (with the mass concentration of 0.5% -2.0%), stirring for crystallization, and filtering for the second time to obtain a diazonium quinone sulfonate crude product;

(4) And (3) washing the diazonaphthoquinone sulfonate crude product obtained in the step (3) with pure water for three times, and drying under reduced pressure to obtain diazonaphthoquinone sulfonate.

In addition to the preferred diazonaphthoquinone esters exemplified above, other diazonaphthoquinone sulfonates commonly used as photosensitive components in positive photoresist compositions may be used as component (B), for example: and esterification reaction products of phenol compounds such as polyhydroxybenzophenone and alkyl gallate and naphthoquinone diazide sulfonic acid compounds. The other naphthoquinone diazide ester may be used in an arbitrary selection of 1 or 2 or more.

The amount of the other naphthoquinone diazide ester used is 80 mass% or less in the component (B), and particularly preferably 50 mass% or less in view of improving the effect of the present invention.

The amount of the component (B) in the positive photoresist composition of the present invention is 20 to 70 mass%, preferably 25 to 60 mass% based on the total amount of the component (A) and the component (C).

By setting the blending amount of the component (B) to the above lower limit value or more, an image faithful to the pattern can be obtained. When the upper limit value is set to be equal to or less than the above, deterioration in sensitivity can be prevented, and uniformity and resolution of the formed resist film can be improved.

In the field of semiconductors including display panels (LCDs), resist materials having sensitivity in the range of 30 to 50mJ are required from the viewpoints of improvement in productivity and process control.

In addition, in the manufacture of semiconductor devices, a disc-shaped silicon wafer having a diameter of 8 inches (about 200 mm) to 12 inches (about 300 mm) is used at the maximum, whereas in the manufacture of LCDs, a square glass substrate having a diameter of 360mm×460mm is used at the minimum. Therefore, in view of improvement in productivity, it is desirable to increase the exposure area as large as possible, at least as large as about 100mm ², and it is generally preferable to use exposure processing under a low NA (numerical aperture of lens) condition for manufacturing an LCD. In order to form an integrated circuit portion on a substrate in addition to a display portion, the substrate tends to be further enlarged, and exposure is required under a lower NA condition than in the case of ordinary LCD production, and exposure treatment under a low NA condition of 0.3 or less is preferably used, and particularly 0.2 or less is preferably used.

In the display panel LCD, for example, the pattern size of the display portion is 2 to 10 μm, whereas the integrated circuit portion is formed in a fine size of 0.5 to 2.0 μm. Therefore, it is preferable that a fine resist pattern of 0.5 to 2.0 μm can be formed. However, there is a problem of poor resolution when performing exposure processing under the low NA condition as described above.

In addition, a positive photoresist composition used for manufacturing a display panel LCD is required to have good linearity characteristics for simultaneously and accurately forming a resist pattern of a display portion and an integrated circuit portion having large dimensional differences, and also to have good depth of focus (DOF) characteristics because a glass substrate having a surface smoothness lower than that of a silicon wafer is used.

According to the present invention, by using the specific multi-strong integration compound represented by the general formula (I) and the diazonaphthoquinone sulfonyl chloride (II) reaction product as the component (B), a positive photoresist composition can be obtained that satisfies both high sensitivity and high resolution even under low NA conditions and that has excellent characteristics such as linearity and DOF.

Component (C)

(C) The component (a) is a phenolic hydroxyl group-containing compound. By using the component (C), a positive resist composition suitable for a system LCD having excellent sensitivity improving effect, high sensitivity and high resolution even in an i-line exposure treatment under a low NA condition and good linearity can be obtained.

The molecular weight (M) of the component (C) is preferably 1000 or less, more preferably 700 or less, and substantially 200 or more, more preferably 300 or more.

(C) The phenolic hydroxyl group-containing compound used as the sensitizer or sensitizer for the resist composition is generally not particularly limited, and 1 or 2 or more of the components may be arbitrarily selected and used, and preferably those satisfying the molecular weight conditions described above are used. Among them, the phenol compound represented by the following general formula (III) exhibits good characteristics as described above.

Wherein R ⁴～R¹¹ each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a cycloalkyl group having 3 to 6 carbon atoms; r ¹³、R¹⁴ each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; r ¹² may be a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and in this case, Q ¹ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a residue represented by the following formula (IV).

(Wherein R ¹⁵ and R ¹⁶ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a cycloalkyl group having 3 to 6 carbon atoms; g represents an integer of 0 to 3), and Q ¹ may be bonded to the terminal of R ¹², in which case Q ¹ and R ¹² and the carbon atoms between Q ¹ and R ¹² together represent a cycloalkyl group having 3 to 6 carbon chains; e. f represents an integer of 1 to 3, h represents an integer of 0 to 3, and R ⁶、R⁹ or R ¹¹ are absent when e, f or h is 3; m represents an integer of 0 to 3.

From the viewpoint of the effect, the amount of component (C) to be blended is 10 to 70% by mass, preferably 20 to 60% by mass, based on component (A).

Component (D)

(D) The component (c) is not particularly limited as long as it is a general organic solvent used in a resist composition, and 1 or 2 or more kinds of components may be selected, and propylene glycol monoalkyl ether acetate and/or 2-heptanone may be contained therein; the coating type is preferable because of excellent coating type and excellent uniformity of film thickness of a resist film on a large glass substrate.

In addition, both propylene glycol monoalkyl ether acetate and 2-heptanone may be used simultaneously, but when used alone or in combination with other organic solvents, it is generally preferable in terms of film thickness uniformity when coating by spin coating or the like.

The propylene glycol monoalkyl ether acetate is preferably contained in the component (D) in an amount of 50 to 100% by mass.

Propylene glycol monomethyl ether acetate is a material having a linear or branched alkyl group having 1 to 3 carbon atoms, and among them, propylene glycol monomethyl ether acetate (hereinafter abbreviated as PGMEA) is particularly preferable because it is excellent in uniformity of film thickness of a resist film on a large glass substrate.

On the other hand, the use of 2-heptanone is not particularly limited, and as described above, it is a preferable solvent when the non-benzophenone photosensitive component as the naphthoquinone diazide ester of (B) is combined.

The 2-heptanone is a very desirable solvent because it has excellent heat resistance and provides a resist composition with less scum (scum) than PGMEA.

When 2-heptanone is used alone or in combination with other organic solvents, it is preferable that the component (D) contains 50 to 100% by mass.

In addition, other solvents may be mixed with the above preferred solvents for use.

For example, when an alkyl lactate such as methyl lactate or ethyl lactate (preferably ethyl lactate) is blended, a resist pattern having excellent uniformity of film thickness of a resist film and good shape can be formed, which is preferable.

When propylene glycol monoalkyl ether acetate and alkyl lactate are used in combination, the amount of ethyl lactate is 0.1 to 10 times, preferably 1 to 5 times by mass based on the propylene glycol monoalkyl ether acetate.

In addition, organic solvents such as gamma-butyrolactone and propylene glycol monobutyl ether may be used.

When gamma-butyrolactone is used, the amount is 0.01 to 1 times, preferably 0.05 to 0.5 times, the amount of the propylene glycol monoalkyl ether acetate.

Further, specific examples of other organic solvents that can be blended include the following:

Namely, ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, etc.; polyvalent alcohols such as ethylene glycol, propylene glycol, diethylene glycol, ethylene glycol monoacetate, propylene glycol monoacetate, diethylene glycol monoacetate, and monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether, and monophenyl ether thereof, and derivatives thereof; cyclic ethers such as dioxane; esters such as methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, and ethyl ethoxypropionate.

When the solvent is used, the component (D) preferably contains 50% by mass or less.

Within the range of not impairing the object of the present invention, the positive-type resist composition of the present invention may further contain additives having compatibility, for example: resins, plasticizers, storage stabilizers, surfactants, colorants for making developed images clearer, sensitizers for making sensitization effects more improved, dyes for reducing halation, adhesion promoters, and other conventional additives added for improving resist film properties and the like.

As the halation reducing dye, the following ultraviolet absorbers may be used, such as: 2,2', 4' -tetrahydroxybenzophenone, 4-dimethylamino-2 ',4' -dihydroxybenzophenone, 5-amino-3-methyl-1-phenyl-4- (4-hydroxyphenylazo) pyrazole, 4-dimethylamino-4 '-hydroxyazobenzene, 4-diethylamino-4' -ethoxyazobenzene, 4-diethylaminoazobenzene, curcumin, and the like.

The surfactant may be added to prevent streaks, etc., and for example, the following surfactants may be used: fluorine-based surfactants such as Fall FC-430, FC431 (trade name, manufactured by Sumitomo 3M Co., ltd.), and Fall EF122A, EF122B, EF122C, EF (trade name, fall-Fall, manufactured by Fall Konj Co., ltd.), and Fall R-08 (trade name, manufactured by Dain ink chemical industry Co., ltd.), and the like.

A preferred method of preparing the positive photoresist composition of the present invention is: the component (A), the component (B), the component (C) and other components used as needed are dissolved in the organic solvent (D).

In order to dissolve the components (a) to (C) and other components used as needed, a uniform positive resist composition can be obtained, and the amount of the component (D) to be used can be appropriately adjusted. The solid content concentration [ (A) to (C) and other components used if necessary ] is preferably 10 to 50% by mass, more preferably 20 to 35% by mass.

The positive photoresist composition of the present invention is preferably prepared such that the Mw of the solid content (hereinafter referred to as resist molecular weight) contained in the photoresist composition is in the range of 5000 to 30000, more preferably 6000 to 10000. By setting the Mw of the solid content of the photoresist composition to the above range, high resolution can be achieved without lowering sensitivity, and a positive photoresist composition having excellent linearity and DOF characteristics and also excellent heat resistance can be obtained. By setting the Mw of the solid content of the photoresist composition to the above range, high resolution can be achieved without lowering sensitivity, and a positive photoresist composition having excellent linearity and DOF characteristics and also excellent heat resistance can be obtained.

When the molecular weight of the photoresist is less than the above range, resolution, linearity, DOF characteristics and heat resistance become insufficient, and when exceeding the above range, deterioration of sensitivity is remarkable, and coatability of the resist composition may be impaired.

In this specification, the molecular weight of the resist can be measured by the following GPC system.

Device name: SYSTEM11 (product name, manufactured by Zhaohe electric company)

Pre-column: KF-G (product name, shodex Co., ltd.)

Column: KF-805, KF-803, KF-802 (product name, manufactured by Shodex Co., ltd.)

A detector: UV41 (product name, manufactured by Shodex Co., ltd.) was measured at 280 nm.

Solvents, etc.: tetrahydrofuran was flowed down at a flow rate of 1.0 ml/min and measured at 35 ℃.

Method for preparing measurement sample: the photoresist composition to be measured was adjusted so that the solid content concentration was 30 mass%, and diluted with tetrahydrofuran to prepare a measurement sample having a solid content concentration of 0.1 mass%. 20. Mu.l of the measurement sample was injected into the apparatus to measure.

In addition, in the manufacture of a display panel LCD, instead of the g-line (436 nm) exposure used in the conventional manufacture of an LCD, the use of i-line (365 nm) exposure having a shorter wavelength may improve resolution by such a photolithography technique. In accordance with the present invention, the positive resist composition using a non-benzophenone compound as the component (B) and optionally the component (C) can suppress the absorption of i-lines due to the component (B) and the component (C), and thus is suitable for the i-line exposure treatment, and can achieve further higher resolution.

In the preparation of the positive photoresist composition of the present invention, the following preparation methods are used to control the molecular weight of the resist to the above-mentioned suitable range: (1) In order to adjust the Mw of the component (A) to the above range, the component (A) is subjected to a fractionation operation before mixing, and the Mw of the component (A) is adjusted to an appropriate range in advance; (2) A method in which a plurality of components (A) having different Mw are prepared and appropriately blended to adjust the Mw of the solid component within the above-mentioned range.

In particular, according to the method of the above (2), the molecular weight of the resist and the sensitivity can be easily adjusted.

Method for Forming resist Pattern

The following is an example of a preferred method for forming a resist pattern in the production of a display panel LCD using the positive photoresist composition of the present invention.

First, the positive photoresist composition of the present invention is coated on a substrate by a spin coater to form a coating film. The substrate is preferably a glass substrate. Amorphous silicon is generally used as a glass substrate, and low-temperature polysilicon or the like is preferable in the field of display panel LCDs. Since the positive photoresist composition of the present invention has excellent resolution under low NA conditions, a large substrate of 550mm×650mm or more can be used as the glass substrate.

Then, the glass substrate on which the coating film is formed is subjected to a heat treatment (pre-baking) at 100 to 140 ℃ to remove the residual solvent, thereby forming a resist film. The preferred pre-drying method is: adjacent baking is provided with a space between the electric heating plate and the base plate.

The resist film is then selectively exposed to light using a mask on which a mask pattern is drawn.

In order to form a fine pattern, an i-line (365 nm) is preferably used as a light source. The exposure treatment used for the exposure is preferably: the NA is 0.3 or less, preferably 0.2 or less, more preferably 0.15 or less.

Then, the selectively exposed resist film is subjected to a heat treatment (post exposure bake: PEB). As the PEB method, for example, there may be mentioned a method of performing adjacent baking with a space between the electric heating plate and the substrate and directly baking without a space, and in order to prevent warpage of the substrate from occurring, it is preferable to perform adjacent baking and then directly baking. The heating temperature is preferably 90 to 150℃and particularly preferably 100 to 140 ℃.

The resist film after PEB is developed with a developer, for example, an aqueous alkali solution such as 1 to 10 mass% tetramethylammonium hydroxide, and the exposed portion is dissolved and removed, whereby a resist pattern for an integrated circuit and a resist pattern for a liquid crystal display portion can be simultaneously formed on a substrate.

Then, the developer remaining on the surface of the resist pattern is rinsed with a rinse solution such as pure water to form a resist pattern.

In the method for forming a resist pattern, in the step of performing the selective exposure in the production of a display panel LCD, it is preferable to use, as the mask, a mask on which both a mask pattern for forming a resist pattern of 2.0 μm or less and a mask pattern for forming a resist pattern exceeding 2.0 μm are drawn.

The positive photoresist composition for LCD of the present invention has excellent resolution, so that a resist pattern faithfully reproducing a fine pattern of a mask pattern can be obtained. Thus, in the step of simultaneously forming the resist patterns, a resist pattern for an integrated circuit having a pattern size of 2.0 μm or less or a resist pattern for a liquid crystal display portion having a pattern size of more than 2.0 μm can be simultaneously formed on the substrate.

Examples

The present invention will be described in detail with reference to examples.

Resist patterns were formed in the following order using the positive resist compositions prepared in examples 1 to 5 and comparative examples 1 to 2, and evaluated.

Evaluation method

(1) Formation of resist pattern

A resist coating apparatus for a large substrate (apparatus name: TR36000 Tokyo applied chemical Co., ltd.) was used to coat a glass substrate (550 mm. Times.650 mm) on which a Ti film was formed with a positive resist composition, then the temperature of an electric heating plate was set to 100℃and the 1st drying was carried out for 90 seconds by adjacent baking at an interval of about 1mm, then the temperature of the electric heating plate was set to 90℃and the 2 nd drying was carried out for 90 seconds by adjacent baking at an interval of about 0.5mm, thereby forming a resist film having a film thickness of 1.5. Mu.m.

Then, by using a test pattern mask (i.e., a device name: FX-702J, manufactured by nikon, na=0.14) on which a mask pattern for reproducing a 3.0 μm L & S resist pattern and a 1.5 μm L & S resist pattern are simultaneously drawn, selective exposure was performed by using an i-line exposure device (an exposure dose (Eop exposure dose) capable of faithfully reproducing 1.5 μm L & S.

Then, the electric heating plate was brought to 120℃and heat-treated for 30 seconds by adjacent drying at intervals of 0.5mm, and then heat-treated for 60 seconds by direct drying without intervals at the same temperature.

Then, a developing device (device name: TD-39000D, manufactured by Tokyo applied chemical Co., ltd.) equipped with a slit coater nozzle was used, and a 2.38 mass% aqueous TMAH solution at 23℃was uniformly applied to the substrate for 10 seconds, and after holding for 55 seconds, the substrate was washed with water for 30 seconds, and then spin-dried.

(2) Sensitivity and film residue evaluation

Stability test of photoresist composition:

the photoresist compositions prepared in each example and comparative example were stored in a constant temperature oven at 25℃and subjected to sampling test on days 20, 30 and 40;

Spin-coating photoresist on a silicon wafer, vacuum-drying the silicon wafer by a vacuum drying oven (VCD), and baking the silicon wafer for 90 seconds on a hot plate at 110 ℃ to form a photoresist coating, wherein the thickness of the coating is about 1.5 mu m measured by a film thickness meter;

Then, the photoresist layer was exposed to light of different energy using an exposure machine having a wavelength of g+h+i, and after exposure, developed with 2.38wt% tetramethylammonium hydroxide (TMAH) for 70s, washed with water for 25s, and then dried to remove the exposed portion, thereby forming a photoresist pattern.

Evaluation of stability of the resist composition: checking the thickness of the photoresist layer before and after exposure by a film thickness meter, and calculating the residual film rate of the photoresist;

The energy just after exposure and development is recorded, and the sensitivity of the photoresist is calculated.

The stability of the photoresist was evaluated based on sensitivity and film residue. (resist composition)

The following materials were prepared as the components (A) to (D).

(A) The components are as follows:

(A1) Novolak resins synthesized according to the usual method with 1mol of mixed phenol of m-cresol/3, 4-xylenol=8/2 (molar ratio) and 0.82mol of formaldehyde, mw=20000, mw/mn=5.2

(B) The components are as follows:

Into a 500mL four-necked flask, nitrogen was introduced, 270mL of 1, 4-dioxane was introduced under a nitrogen atmosphere, and the charging ratio of the raw material polyhydroxy phenol (I) to the diazonaphthoquinone sulfonyl chloride (II) was 1:3.7mol, stirring and mixing uniformly, and keeping the system temperature at 25-30 ℃; heating to 30 ℃, slowly adding 10.0g of triethylamine dropwise, and finishing dripping within 3.0 hours; the temperature of the system is kept between 30 and 33 ℃, the stirring reaction is continued for about 1.0 hour, and the reaction is finished; filtering to remove solid precipitated in the system, slowly adding the mother solution into 1000mL of pre-prepared 1.0wt% diluted hydrochloric acid, stirring for crystallization for 1.0 hour, and filtering; washing the filter cake with pure water for three times, and filtering; the wet cake was dried at 150mbar at 40℃to give the product as a pale yellow solid.

The following product B was obtained by the above-described method.

TABLE 1

(C) The components are as follows:

(C1) Bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -3, 4-dihydroxyphenyl methane

(D) The components are as follows:

(D1)PGMEA

examples 1 to 5 and comparative examples 1 to 2

The components (A) to (C) were used in the amounts shown in Table 2, and a surfactant (product name "Fangjinfang R-08"; manufactured by Daiki ink chemical industry Co., ltd.) was used in an amount corresponding to 450ppm based on the total mass of the components (A) to (C), and dissolved in the component (D) shown in Table 2, and then filtered through a membrane filter having a pore diameter of 0.2. Mu.m, to prepare a positive photoresist composition. The resist molecular weights of the positive photoresist compositions obtained are shown in table 2.

Each of the items (1) to (2) was evaluated for the positive photoresist composition obtained. The results are shown in Table 3.

TABLE 2

Wherein: the compound (VI) was TPPA-PAC (Japanese Toyo Synthesis Co., ltd.; the compound (VII) was THPE-PAC (Korea beauty source Special chemical Co., ltd.).

TABLE 3 Table 3

From the above test results, compared with examples 1 to 5, the sensitivity and the film residue ratio of comparative examples 1 to 2 are more and more different from those of the 20-day measurement results with the lapse of time, and the stability is poor; the photoresist compositions provided in examples 1 to 5, which are within the scope of the present invention, have excellent sensitivity and stability, and high film residue ratio, as compared with those prepared using photosensitizers which have been widely commercialized in the market.

The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A positive photoresist composition characterized by: comprises (A) an alkali-soluble resin, (B) a diazonaphthoquinone sulfonate, (C) a phenolic hydroxyl-containing compound having a molecular weight of 1000 or less, and (D) an organic solvent, wherein the component (B) comprises a reaction product of a polyhydric phenol compound represented by the following general formula (I) and a diazonaphthoquinone sulfonyl chloride represented by the following general formula (II),

Wherein R1, R2 and R3 each independently represent hydrogen, halogen, C1-C18 linear or branched alkyl, C6-C12 aryl, C1-C8 alkoxy, C1-C8 alkylthio,

A C2-C10 unsaturated hydrocarbon group, a C3-C12 cycloalkyl group, a C4-C12 cycloalkylalkyl group, a C,

C1-C9 alkanoyl, C7-C13 aroyl, C3-C6 heterocyclyl optionally substituted by O, S or N atoms, C1-C18 alkylamino or arylamino; a. b and c each independently represent an integer of 0 to 2; x, y, z each independently represent an integer between 0 and 3; the diazonaphthoquinone sulfonyl chloride (II) is one of the following structural compounds;

2. The positive resist composition according to claim 1, wherein the component (B) contains a reaction product of R1, R2, and R3 in the general formula (I) each independently represents hydrogen, a C1 to C6 linear or branched alkyl group, a C6 to C12 aryl group, a C1 to C6 alkoxy polyhydric phenol, and a diazonaphthoquinone sulfonyl chloride represented by (II).

3. The positive-working photoresist composition according to claim 1, wherein the component (B) contains at least one polyhydric phenol compound (I) selected from the following structural compounds:

4. The positive photoresist composition according to claim 1, wherein the component (D) contains propylene glycol monoalkyl ether acetate or/and 2-heptanone.

5. The positive-working photoresist composition according to claim 1, which is used for an i-line exposure process.

6. The positive-working photoresist composition according to claim 1, which is used for exposure treatment with NA of 0.3 or less.

7. A method for forming a resist pattern, comprising the steps of: (1) A step of forming a coating film by applying the positive photoresist composition according to any one of claims 1 to 6 onto a substrate; (2) A step of heating the substrate on which the coating film is formed, and forming a resist film on the substrate; (3) A step of selectively exposing the resist film using a mask on which both a resist pattern forming mask pattern of 2.0 [ mu ] m or less and a resist pattern forming mask pattern of more than 2.0 [ mu ] m are drawn; (4) A step of performing a heat treatment on the selectively exposed resist film; (5) And (3) a step of simultaneously forming a resist pattern for an integrated circuit having a pattern size of 2.0 [ mu ] m or less and a resist pattern for a liquid crystal display portion having a pattern size of more than 2.0 [ mu ] m on the substrate by subjecting the heat-treated resist film of (4) to a development treatment with an aqueous alkali solution.

8. The method for forming a resist pattern according to claim 6, wherein the step of (3) performing selective exposure uses an i-line as a light source and is performed by exposure treatment under a low NA condition having an NA of 0.3 or less.