JP5507331B2 - Reaction development image forming method - Google Patents

Description

  The present invention relates to a photoresist technique that can be used for manufacturing a semiconductor integrated circuit, a printed wiring board, a liquid crystal panel, and the like, and more specifically, a film formed using a polyester resin having a specific structure and a photoacid generator. The present invention relates to a photoresist technique in which a negative image is formed through light irradiation and a development process.

Photoresists are commonly used in photolithographic organic polymers used in the related art in photographic deck processing, for the production of printed circuit boards and printed circuit boards, or for the production of semiconductor laminates in microelectronics. .
In order to create circuit structures in the manufacture of microelectronic semiconductor integrated components, the semiconductor substrate is coated with a photoresist. Imagewise exposure of the photoresist layer and subsequent development creates a photoresist relief structure. This relief structure is used on a semiconductor substrate as a mask for creating an actual circuit pattern by etching-doping or coating using a metal or other semiconductor or insulating substrate. Thereafter, the photoresist mask is usually removed. A microchip relief structure is formed on the substrate using a plurality of such processing cycles.
Two different types of photoresists are known: a positive resist and a negative resist. The difference between the two types is that the exposed area of the positive photoresist is removed by the development process, leaving the unexposed area as a layer on the substrate. On the other hand, the irradiation area of the negative working photoresist remains as a relief structure.
The present inventors have already developed a method called “reactive development image forming method” for carrying out a positive photoresist using a resin having a carbonyl group (C═O) bonded to a hetero atom in the main chain. (Patent Document 1, Non-Patent Document 1).
The present inventors have developed a method capable of efficiently producing a negative photoresist by improving the “reactive development image forming method” (Patent Document 2).

JP2003-76013 JP2007-328333

J. Microlith. Microfab. Microsyst., 3, 159-167 (2004).

  An object of the present invention is to provide means for improving the heat resistance of a negative photoresist formed by a conventional reaction development image forming method (Patent Document 2) and ensuring a fast development time.

When the present inventors perform a negative photoresist using a polyester resin, the polyester resin has the following general formula:
And a repeating unit having a molecular weight of X of 100 or more in the formula, X becomes bulky, and the penetration of the developer into the polyester resin is facilitated, and the development time is shortened. The present inventors have found that a mold photoresist can be properly formed and have completed the present invention.

That is, the present invention is a photoresist composition containing a polyester resin and a photoacid generator, wherein the polyester resin has at least one structural formula shown below.
(In the formula, X has a molecular weight of 100 or more, and —C (R ⁵ R ⁶ ) — (wherein R ⁵ and R ⁶ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms). Represents a phenyl group or a perfluoroalkyl group having 1 to 3 carbon atoms.), An optionally substituted cycloalkylidene group having 5 to 12 carbon atoms, and an optionally substituted 9,9. '-Fluorenylidene group, 1,8-menthanediyl group which may have a substituent, 2,8-mentanediyl group which may have a substituent, pyrazylidene group which may have a substituent, substituted A phthalidyl group which may have a group, an arylene group having 6 to 12 carbon atoms which may have a substituent, or —C (CH ₃ ) ₂ —ph—C (CH ₃ ) ₂ — (provided that ph represents a phenylene group), and Z has a substituent. Also represents an arylene group or an alkylene group, ^{R 1} and ^{R 2} are each independently a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, aryl having 6 to 12 carbon atoms A group selected from the group of a group, an aryl-substituted alkenyl group having 7 to 13 carbon atoms and a fluoroalkyl group having 1 to 6 carbon atoms, and m and n each independently represents an integer of 0 to 4). A repeating unit represented by (1),
And at least one of the following structural formulas:
(In the formula, Y has a molecular weight of less than 100 and is a single bond, —O—, —CO—, —S—, —SO—, —SO ₂ —, —C (R ⁷ R ⁸ ) — (provided that , R ⁷ and R ⁸ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group or a trifluoromethyl group.), And optionally having 5 to 5 carbon atoms. 7 cycloalkylidene group, an optionally substituted pyraziridene group, or an optionally substituted phenylene group, R ³ and R ⁴ each independently represent a halogen atom, a carbon number It is selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aryl-substituted alkenyl group having 7 to 13 carbon atoms, and a fluoroalkyl group having 1 to 12 carbon atoms. Represents a group, Z represents the same as above, and o and p represent Each independently represents an integer of 0 to 4), and the content (molar ratio) of the repeating unit (1) relative to all the repeating units. Is a 0.10-1.00 photoresist composition.

  The present invention also provides a step of providing a photoresist layer comprising the photoresist composition on a substrate, masking it with a desired pattern, irradiating the pattern surface with ultraviolet light, and applying the photoresist layer to a developer. This is a reactive development image forming method comprising a developing stage to be processed, wherein the developer comprises a solvent containing tetra-substituted ammonium hydroxide, a low molecular alcohol and water.

It is a figure which shows the SEM photograph of the photoresist formed in each Example. (1) Example 1, (2) Example 2, (3) Example 3, (4) Example 4 It is a figure which shows the SEM photograph of the photoresist formed in each Example. (5) Example 5, (6) Example 6, (7) Example 7, (8) Example 8 It is a figure which shows the SEM photograph of the photoresist formed in each Example. (9) Example 9, (10) Example 10, (11) Example 11, (12) Example 12 It is a figure which shows the SEM photograph of the photoresist formed in each Example. (13) Example 13, (14) Comparative Example 2

The negative photoresist composition of the present invention contains a polyester resin and a photoacid generator.
This polyester resin comprises at least one repeating unit (1) and at least one repeating unit (2). The polymer may be a block or random.

The repeating unit (1) is represented by the following general formula (1).
As this repeating unit (1), the following general formula (1) ′
Those having a structural unit represented by the formula are preferred because they are excellent in heat resistance and mechanical strength of the polyester resin.

In the present invention, it is necessary that the molecular weight of X is 100 or more.
Specifically, X has a molecular weight of 100 or more and is any one of the following divalent groups. This divalent group is —C (R ⁵ R ⁶ ) — (wherein R ⁵ and R ⁶ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, or 1 to 1 carbon atoms). 3), a cycloalkylidene group having 5 to 12 carbon atoms which may have a substituent, a 9,9′-fluorenylidene group which may have a substituent, and a substituent. 1,8-menthanediyl group which may have, 2,8-mentanediyl group which may have a substituent, pyrazylidene group which may have a substituent, may have a substituent A phthalidyl group, an arylene group having 6 to 12 carbon atoms which may have a substituent, or —C (CH ₃ ) ₂ —ph—C (CH ₃ ) ₂ — (wherein ph represents a phenylene group.) Since it is more excellent in heat resistance, preferably -C R ⁵ R ⁶⁾ -. (However, ^{R 5} and ^{R 6} are as defined above), a 9,9'-fluorenylidene group. Examples of the substituent include an alkyl group such as an alkyl group having 1 to 6 carbon atoms, an alkoxyl group such as an alkoxyl group having 1 to 6 carbon atoms, an aryl group such as an aryl group having 6 to 12 carbon atoms, an aralkyl group, or the like. An aryl-substituted alkenyl group such as an aralkyl group having 7 to 13 carbon atoms or an aryl-substituted alkenyl group, a fluoroalkyl group such as a fluoroalkyl group having 1 to 6 carbon atoms, and a halogen atom such as fluorine, preferably a carbon number A 1-6 alkyl group, for example, a methyl group, a C6-C12 aryl group, for example, a phenyl group, and a halogen atom are mentioned.

Examples of the alkyl group having 1 to 6 carbon atoms represented by R ⁵ and R ⁶ include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, Examples thereof include a tert-butyl group, an n-pentyl group, and an n-hexyl group. In these, a methyl group, an ethyl group, and n-propyl group are mentioned as a suitable thing. A trifluoromethyl group etc. are mentioned as a C1-C3 perfluoroalkyl group. Further, examples of the cycloalkylidene group having 5 to 12 carbon atoms include a cyclopentylidene group, a cyclohexylidene group, a cycloheptylidene group, a cyclooctylidene group, and the like, and examples of the arylene group having 6 to 12 carbon atoms include Examples include a phenylene group, a biphenylene group, a 1,4-phenylenebis (1-methylethylidene) group, and a 1,3-phenylenebis (1-methylethylidene) group.

  Z represents an arylene group or an alkylene group, preferably an arylene group, and these may have a substituent described for X above. The arylene group is preferably an arylene group having 6 to 12 carbon atoms, for example, a phenylene group, a biphenylene group, a 1,4-phenylenebis (1-methylethylidene) group, or a 1,3-phenylenebis (1-methylethylidene). Group), preferably a phenylene group. The alkylene group is preferably an alkyl group having 1 to 6 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, A tert-butyl group, an n-pentyl group, and an n-hexyl group, preferably a methyl group, an ethyl group, and an n-propyl group.

In this general formula (1), R ¹ and R ² are each independently a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, A group selected from the group consisting of an aryl-substituted alkenyl group having 7 to 13 carbon atoms and a fluoroalkyl group having 1 to 6 carbon atoms.
Examples of the alkyl group having 1 to 6 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, tert-butyl group, n- A pentyl group, n-hexyl group, cyclopentyl group, cyclohexyl group and the like can be mentioned. Moreover, as a C1-C6 alkoxy group, a methoxy group, an ethoxy group, n-propoxy group, i-propoxy group, i-butoxy group, sec-butoxy group, tert-butoxy group, n-pentyloxy group, Examples include n-hexyloxy group. Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a biphenyl group, a triphenyl group, and a naphthyl group. Examples of the aryl-substituted alkenyl group having 7 to 13 carbon atoms include a benzyl group, a phenethyl group, and styryl. Group, cinnamyl group and the like. Furthermore, as a C1-C6 fluoroalkyl group, a monofluoromethyl group, a difluoromethyl group, a trifluoromethyl group, etc. are mentioned.

Among various substituents represented by R ¹ and R ² in the general formula (1), those having 1 to 6 carbon atoms are preferable because of excellent heat resistance, and more preferably a methyl group. In addition, among the above various substituents, a cyclohexyl group, a methoxy group, a phenyl group, a trifluoromethyl group, and the like are preferable.
And m and n in the general formula (1) may be each independently 0, that is, a hydrogen atom, or may have 1 to 4 substituents. About this m and n, what is 0-2 is more preferable.

The repeating unit (2) is represented by the following general formula (2).
As this repeating unit (2), the following general formula (2) ′
Those having a structural unit represented by the formula are preferred because they are excellent in heat resistance and mechanical strength of the polyester resin.

In the present invention, the molecular weight of Y is less than 100.
Specifically, Y has a molecular weight of less than 100 and is any one of the following divalent groups. This divalent group is a single bond, —O—, —CO—, —S—, —SO—, —SO ₂ —, —C (R ⁷ R ⁸ ) — (where R ⁷ and R ⁸ are Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group or a trifluoromethyl group, provided that the molecular weight of —C (R ⁷ R ⁸ ) — is a combination of R ⁷ and R ⁸ . Is less than 100.), a substituted or unsubstituted cycloalkylidene group having 5 to 7 carbon atoms, a substituted or unsubstituted pyrazilidene group, or a substituted or unsubstituted phenylene group, preferably a single bond or —C (R ⁷ R ⁸ ) — (where R ⁷ and R ⁸ represent an alkyl group having 1 to 6 carbon atoms, particularly a methyl group). Examples of the substituent include those described for X.

Examples of the alkyl group having 1 to 6 carbon atoms represented by R ⁷ and R ⁸ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, Examples thereof include a tert-butyl group, an n-pentyl group, and an n-hexyl group. In these, a methyl group, an ethyl group, and n-propyl group are mentioned as a suitable thing. Furthermore, examples of the cycloalkylidene group having 5 to 7 carbon atoms include a cyclopentylidene group, a cyclohexylidene group, and a cycloheptylidene group.
The divalent group represented by Y is —C (R ⁷ R ⁸ ) — (wherein R ⁷ and R ⁸ are defined in the same manner as above), a substituted or unsubstituted cycloalkylidene group. A thing is preferable from being more excellent in heat resistance.
Z is the same as above.

R ³ and R ⁴ are each independently a halogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aryl substitution having 7 to 13 carbon atoms. A group selected from the group of an alkenyl group and a fluoroalkyl group having 1 to 12 carbon atoms is represented.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. And as a C1-C12 alkyl group, a methyl group, an ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, tert-butyl group, n -Pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, cyclopentyl group, cyclohexyl group and the like. Moreover, as a C1-C12 alkoxy group, a methoxy group, an ethoxy group, n-propoxy group, i-propoxy group, i-butoxy group, sec-butoxy group, tert-butoxy group, n-pentyloxy group, Examples include an n-hexyloxy group, an n-heptyloxy group, an n-octyloxy group, an n-nonyloxy group, an n-decyloxy group, an n-undecyloxy group, and an n-dodecyloxy group. Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a biphenyl group, a triphenyl group, and a naphthyl group. Examples of the aryl-substituted alkenyl group having 7 to 13 carbon atoms include a benzyl group, a phenethyl group, and styryl. Group, cinnamyl group and the like. Furthermore, as a C1-C12 fluoroalkyl group, a monofluoromethyl group, a difluoromethyl group, a trifluoromethyl group, etc. are mentioned. Among these various substituents, a methyl group, an ethyl group, a cyclohexyl group, a phenyl group and the like are preferable.
o and p may each independently be 0, or may have 1 to 4 substituents as described above. About this o and p, what is 0-2 is more preferable.

In this polyester resin, the repeating unit (1) is essential, but the repeating unit (2) is optional, and the content ratio (molar ratio) of the repeating unit (1) to all the repeating units is 0.10. -1.00, preferably 0.25-1.00.
Further, each of the repeating units (1) or (1) ′ and (2) or (2) ′ may be one kind or two or more kinds, but preferably one kind.
The molecular weight of the polyester resin used in the present invention is usually about 10,000 to 50,000.

This polyester-based resin may be synthesized by any method. For example, the following three types of monomers corresponding to the above repeating units can be synthesized by synthesizing them under conventional polyester synthesis conditions. These three types may be mixed and polymerized, or a combination of these may be combined as appropriate before once synthesizing a prepolymer or the like. A derivative thereof (for example, a halide represented by MOC-Z-COM (wherein M represents a halogen atom or the like)) may be used in place of the dicarboxylic acid of (3).
(Wherein R ^{1 to} R ⁴ , X, Y, X, m, n, o, and p are the same as described above.)

The polymer used in the present invention contains a photoacid generator. Further, an anion regenerant may be included for further shortening the development time.
This anion regenerating agent is preferably subjected to Michael addition, hydrogen abstraction, or nucleophilic attack by the hydroxyl anion in the developing solution during development to form an anionic compound, and further, it remains in the film without volatilization during pre-baking.
This anion regenerant is any of the following compounds.
(1) Compound having a structure represented by the following formula:

In the above formula, A represents a substituent represented by the following formula.
In the formula, B is —NR ⁹ ₂ , —OR ⁹ (excluding —OH), —CR ⁹ ₃ or —SR ⁹ (excluding —SH), preferably —NR ⁹ ₂ or — representing the CR ⁹ _3.
In these formulas, each R ⁹ independently represents a hydrogen atom, an aliphatic group or an aromatic group, preferably an aromatic group, more preferably a phenyl group. Examples of the aliphatic group include alkyl groups such as a methyl group, a propyl group, a hexyl group, and a cyclohexyl group.

(2) Compound having a structure represented by the following formula:
R ¹⁰ -CONHR ⁹
Or R ¹⁰ -COCH (R ⁹ ) ₂
In the formula, each R ¹⁰ independently represents an aliphatic group or an aromatic group. Examples of the aliphatic group include alkyl groups such as a butyl group, an isobutyl group, and a hexyl group, and examples of the aromatic group include a phenyl group and a phenylene group.
R ⁹ is defined as above.

(3) Compound having a structure represented by the following formula:
In the formula, at least one of R ¹¹ represents an aliphatic group or an aromatic group, and the other represents a hydrogen atom. Examples of the aliphatic group include alkyl groups such as an oxymethylene group and an octyl group, and examples of the aromatic group include a phenyl group and a phenylene group.
Q represents an oxygen atom (—O—) or a sulfur atom (—S—).

(4) Compound having a structure represented by the following formula:
^{_{CH (R 12) 2 C (}} R 9) 2 OCO-N (R 9) 2
In the formula, at least one of R ¹² represents an electron withdrawing group, and the other represents a hydrogen atom, an aliphatic group, or an aromatic group. Examples of the aliphatic group include an alkyl group, and examples of the aromatic group include a phenyl group and a phenylene group. Examples of the electron withdrawing group include a fluorenyl group, an organic sulfoxide group, a cyano group, a nitro group, an ester group, a carbonyl group, an amide group, and a pyridyl group, preferably a fluorenyl group. Examples of the aromatic group include a phenyl group and a phenylene group.
R ⁹ is defined as above.

  Examples of such an anion regenerating agent include N-substituted maleimide, N-substituted citraconimide, N-substituted succinimide, N-substituted crotonamide, N, N′-substituted fumaramide, and 4-substituted-3-butene-2. -One, N-substituted benzamide, N-substituted isovaleramide, α-substituted acetophenone, polyamideimide, epoxy resin (for example, bisphenol A diglycidyl ether), N-fluorenylmethoxycarbonyl protected amine and the like.

As an anion regenerant, the following formula
An N-substituted maleimide compound represented by the formula (wherein R ⁹ is defined in the same manner as described above) is more preferable.

  Preferred anion regenerants include, for example, N-methylmaleimide, N-ethylmaleimide, N- (n-propyl) maleimide, N- (n-hexyl) maleimide, N- (n-octyl) maleimide, N-laurylmaleimide N-phenylmaleimide, N-benzylmaleimide, N-cyclohexylmaleimide (N-substituted maleimide compound), N-phenylcitraconimide, N-phenylsuccinimide, N, N'-m-phenylenebismaleimide, N-phenyl Crotonamide, bis (N-phenyl) fumaramide, divinylsulfone, ethyl acetoacetate, 4-phenyl-3-buten-2-one, N-phenylisovaleroamide, N-methylbenzamide, polyamideimide, bisphenol A diglycidyl ether N- (9-fluorenylmethylcarbonyl) -2-methoxyethylamine, 1,4-diphenyl Nyl-1,4-butanedione and the like can be mentioned.

The photoacid generator used in the present invention may be any one that generates acid upon light irradiation. Examples of the photoacid generator include quinonediazide compounds, onium salts, sulfonic acid esters, and organic halogen compounds. The quinonediazide compound includes 1,2-naphthoquinone-2-diazide-5-sulfonic acid or 1,2-naphthoquinone-2-diazide-4-sulfonic acid and a low-molecular aromatic hydroquinone compound such as 2,3,4-trihydroxy. Examples include benzophenone, 2,3,4,4′-tetrahydroxybenzophenone and trihydroxybenzene, such as 1,3,5-trihydroxybenzene, or an ester-forming compound of cresol. Examples of onium salts include triphenylsulfonium hexafluoroantimonate and triphenylsulfonium hexafluorophosphate. These are used with esters such as t-butyl benzoate. Among these, the following formula
(In the formula, R represents an alkyl group or an aryl group. The alkyl group has an alkyl group having 1 to 10 carbon atoms, and the aryl group has an alkyl group having 1 to 3 carbon atoms as a substituent. A preferred phenyl group or an α or β-naphthyl group.), Particularly 1,2-naphthoquinone-2-diazido-5-sulfonic acid-p-cresol ester is preferred.

When an anion regenerator is added, it is preferably 1 to 40% by weight, more preferably 10 to 20% by weight, based on the total solid content in the photoresist (mixture of polymer, anion regenerator and photoacid generator). Used.
The photoacid generator is used in the photoresist in an amount of 5 to 50% by weight, preferably 10 to 40% by weight, more preferably 15 to 30% by weight based on the total solid content.

The photoresist of the present invention may contain additives such as coupling agents, leveling agents, plasticizers, other film-forming resins, surfactants and stabilizers. The total amount of these additives does not exceed 25% by weight based on the total solid content of the photoresist.
The photoresist of the present invention is formulated by mixing or dissolving the components in a solvent or solvent mixture by a method known per se. Once the components are dissolved in the solution, the resulting photoresist solution may be filtered using a filtration membrane having 0.1-1 μm pores.

  Solvents suitable for the production of photoresist solutions are in principle all solvents in which the non-volatile components of the photoresist, such as polymers and photoacid generators and other additives, are sufficiently soluble and do not irreversibly react with these components. It is. Suitable solvents include, for example, aprotic polar solvents such as N-methyl-2-pyrrolidone (hereinafter referred to as “NMP”), butyrolactone, cyclohexanone, diacetoxyethylene glycol, sulfolane, tetramethylurea, N, N-dimethyl. Acetamide, dimethylformamide, dimethyl sulfoxide, acetonitrile, diglyme, phenol, cresol, toluene, methylene chloride, chloroform, tetrahydrofuran, dioxane, acetone and the like.

A photoresist layer can be formed on the substrate using such a photoresist solution. As the substrate, any organic material such as resin, inorganic material, metal, etc. may be used, but a copper substrate or a silicon substrate is preferable.
Coating onto the substrate is usually done by dipping, spraying, roll coating or spin coating. The resulting layer thickness depends on the viscosity, solids content and spin coating speed of the photoresist solution. The photoresist of the present invention can make a layer and a relief structure having a layer thickness of 0.1 to 500 μm, preferably 1 to 100 μm. The thin layer in the multi-layer circuit can be 1-50 μm as a temporary photoresist or as an insulating layer.
After the photoresist is applied to the substrate, it is usually pre-dried at a temperature range of 50 to 120 ° C. An oven or a heating plate can be used. The drying time in the oven is 5 to 60 minutes.

Thereafter, the photoresist layer is irradiated with ultraviolet rays after being masked with a desired pattern. Ultraviolet rays refer to electromagnetic waves having a central wavelength of 250 to 450 nm, preferably 300 to 400 nm. Usually actinic light is used, but high-energy radiation such as X-rays or electron beam rays can also be used. Direct irradiation or via an exposure mask can be performed. A radiation beam can also be applied to the surface of the photoresist layer.
Usually, radiation is performed using an ultraviolet lamp. It is preferable to use a commercially available radiation apparatus such as a contact or non-contact exposure machine, a scanning projection type exposure apparatus or a wafer stepper.

After the exposure, the photoresist layer is developed with a developer.
The developer used in the present invention comprises a solvent containing tetra-substituted ammonium hydroxide, a low molecular alcohol and water.
This tetra-substituted ammonium hydroxide turns the alcohol component in the developer into an alkoxide.
This tetra-substituted ammonium hydroxide is represented by the following formula.
NR ' ₄ OH
In the formula, R ′ may be the same or different and each represents a hydrocarbon group, preferably an alkyl group, more preferably an alkyl group having 1 to 3 carbon atoms.
Preferred tetra-substituted ammonium hydroxides include tetraalkylammonium hydroxides such as tetramethylammonium hydroxide.

  Part of this low molecular alcohol becomes an alkoxide in the developer. Therefore, an alcohol having a molecular weight of 150 or less, particularly an alkyl alcohol having 1 to 8 carbon atoms, preferably 1 to 3 carbon atoms per hydroxyl group, is preferably used. Examples of such low molecular alcohols include methanol, ethanol, 1-propanol, 2-propanol, butanol, octanol, ethylene glycol, 2-methoxyethanol, 2-ethoxyethanol and the like.

  The “solvent containing water” in the developer is a solvent that is compatible with water or a low molecular alcohol and has the ability to dissolve the polymer, the photoacid generator, and the anion regenerant. Examples of such a solvent include NMP, dimethylformamide, dimethyl sulfoxide, tetramethylurea, butyrolactone, diacetoxyethylene glycol, cyclohexanone, polyethylene glycol (number average molecular weight of about 500 or less).

  The composition of a preferred developer is tetra-substituted ammonium hydroxide (such as TMAH) / water / alcohol (such as methanol) / organic solvent (such as NMP), and the weight ratio thereof is preferably 0.05 to 0.3 / 0.5 to 1.5 / 1.0 to 3.0 / 0 to 2.0, more preferably 0.05 to 0.15 / 0.8 to 1.0 / 2.0 to 3.0. / 0 to 1.0.

Development is performed in consideration of the type of polymer and other components, the type of developer, exposure energy, type of development, preliminary drying temperature, development temperature, and development time.
You may wash | clean with a suitable solvent after image development.
The negative photoresist of the present invention can have a polymer coating having a layer thickness of 0.1 to 500 μm, preferably 1 to 100 μm, and a sharp contoured relief structure.

The following examples illustrate the invention, but are not intended to limit the invention. In this example, a photoresist was formed by the following method and observed. The photoresist was produced by filtering the photoresist formulation of each example through a filter membrane having a pore size of 3 μm. This photoresist composition was applied by spin coating on the surface of a copper foil having a diameter of 10 cm subjected to surface treatment. Subsequently, it dried in the infrared hot air dryer. On this photoresist compound coating film, a test pattern (10-200 μm line and space pattern) for a negative photomask is placed, and using a 2 kw ultra-high pressure mercury lamp irradiation device (Oak Seisakusho product: JP-2000G), Irradiation was performed with an exposure amount that would produce an image.
The coating film after the irradiation was immersed or sonicated in the developer, washed with pure water, dried with an infrared lamp, and the resolution was observed. In some examples, the formed photoresist was observed by SEM (manufactured by JEOL Ltd., scanning electron microscope: JSM-6390LV, acceleration voltage: 1.2 kV).

Production Example 1
In a four-necked flask equipped with a glass stir bar with fluororesin plate, thermometer, and dropping funnel, 2.85 g (12.5 mmol) of bisphenol A (manufactured by Tokyo Chemical Industry Co., Ltd.) and 9,9-bis (4 -Hydroxyphenyl) fluorene (Tokyo Kasei Kogyo Co., Ltd.) 13.14 g (37.5 mmol) was added to 80 ml of 1,2-dichloroethane and stirred slowly. After adding 14 ml of triethylamine, flask in an ice bath. The inside was kept at 10 ° C. and stirring was continued for 1 hour. Then, a solution prepared by dissolving 5.08 g (25 mmol) of terephthaloyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) and 5.08 g (25 mmol) of isophthaloyl chloride in 20 ml of 1,2-dichloroethane was dropped using a dropping funnel. The mixture was reacted for 120 minutes in an ice bath. At this time, the temperature in the flask was kept at 10 ° C. The obtained mixture was added dropwise to 1.5 L of methanol and allowed to stand overnight, and then the precipitate was filtered and dried under reduced pressure at 75 ° C. overnight to obtain a crude product. This product was dissolved in warm DMF and then cooled to room temperature. The deposited precipitate was removed by filtration, and then the solution was added dropwise to 1.5 L of methanol. After allowing to stand overnight, the precipitate was filtered and dried under reduced pressure at 120 ° C overnight to obtain a polyarylate copolymer PAr-FL-A (75:25) represented by the following formula in a yield of 89%. It was.
In this chemical formula (Chemical Formula 12), the two carbonyl groups in the aromatic ring to which the carbonyl group is bonded are mixed at the meta and para positions. (Molar ratio) = 1: 1.
When this polyarylate was analyzed by ¹ H-NMR spectrum, the ratio of m: n in the formula was 75:25 as prepared. Further, when the molecular weight of the obtained polymer was measured by gel permeation chromatography (manufactured by Tosoh Corporation, GPC-8020 system, polystyrene standard), the number average molecular weight was 27,000 and the polydispersity was 1.6. It was.

Example 1
After adding 1.0 g of PAr-FL-A (75:25) to 4.8 g of N-methylpyrrolidone (NMP) and dissolving it, diazonaphthoquinone photosensitizer PC-5 (R) (Toyo Gosei) as a photoacid generator 1,2-naphthoquinone-2-diazide-5-sulfonic acid-p-cresol ester) was added and stirred with a stirrer at room temperature for about 1 hour to prepare a photoresist formulation. This solution is applied onto 35μm electrolytic copper foil (matte surface) by spin coating (500rpm / 10sec + 700rpm / 20sec), pre-baked with a far infrared hot air circulation dryer (90 ℃ / 10min), A 11.3 μm photosensitive polyarylate coating was obtained.
This was irradiated with light in the i-line to g-line band by a UV exposure machine (Oak) through a PET photomask. The exposure measured with an illuminometer for the i-line band was 100 mJ / cm ² .
After exposure, it was immersed in 100 g of a developing solution consisting of tetramethylammonium hydroxide (TMAH) /water/ethanol=0.1/0.9/2.0 (weight ratio) at 50 ° C. for a certain period of time, and then washed with 100 g of ion-exchanged water for 1 minute. . As a result, a negative image was obtained. The development time at this time was 10 minutes and 26 seconds. The resolution was 25 μm in a line and space pattern, and the remaining film ratio in the exposed area was 72%. An SEM photograph of this photoresist is shown in FIG.

Example 2
A photosensitive PAr coating film (film thickness: 11.4 μm) obtained by the same operation as in Example 1 was exposed by the same method and exposure amount as in Example 1.
After exposure, the film was immersed in 100 g of a developer solution consisting of TMAH / water / ethanol = 0.1 / 0.9 / 3.0 (weight ratio) at 50 ° C. for a fixed time, and then washed with 100 g of ion-exchanged water for 1 minute. As a result, a negative image was obtained. The development time at this time was 7 minutes and 28 seconds. The resolution was 15 μm in a line and space pattern, and the remaining film ratio in the exposed area was 75%. An SEM photograph of this photoresist is shown in FIG.

Example 3
In NMP4.8g, 1.0g of polyarylate (PAr-FL-A (100: 0), m: n = 100: 0, number average molecular weight 19,000) without the bisphenol A structure-containing unit in the above chemical formula (Chemical Formula 12) After addition and dissolution, 0.2 g of photosensitive agent PC-5 (R) was added and stirred with a stirrer at room temperature for about 1 hour to prepare a photoresist formulation. Spin coating and pre-baking were performed in the same manner as in Example 1 to obtain a photosensitive polyarylate coating film having a thickness of 9.8 μm. Thereafter, light in the i-line to g-line band was irradiated by an ultraviolet exposure machine. The exposure measured with an illuminometer for the i-line band was 100 mJ / cm ² .
The exposed polyarylate coating film was immersed in 100 g of a developer consisting of TMAH / water / ethanol = 0.1 / 0.9 / 2.0 (weight ratio) at 50 ° C. for a fixed time, and then washed with 100 g of ion-exchanged water for 1 minute. . As a result, a negative image was obtained. The development time at this time was 9 minutes. The resolution was 25 μm in a line-and-space pattern, and the remaining film ratio in the exposed area was 66%. An SEM photograph of this photoresist is shown in FIG.

Example 4
A photosensitive PAr coating film (film thickness: 10.7 μm) obtained by the same operation as in Example 3 was exposed by the same method and exposure amount as in Example 3.
After exposure, the film was immersed in 100 g of a developer solution consisting of TMAH / water / ethanol = 0.1 / 0.9 / 3.0 (weight ratio) at 50 ° C. for a fixed time, and then washed with 100 g of ion-exchanged water for 1 minute. As a result, a negative image was obtained. The development time at this time was 9 minutes. The resolution was 40 μm in a line and space pattern, and the remaining film ratio in the exposed area was 64%. An SEM photograph of this photoresist is shown in FIG.

Example 5
After adding 1.0 g of polyarylate (PAr-FL-A (100: 0)), m: n = 100: 0, number average molecular weight 19,000) to NMP4.8 g and dissolving, Photosensitizer PC-5 ( A photoresist formulation was prepared by adding 0.2 g of R) and 0.2 g of N-phenylmaleimide (hereinafter referred to as “PMI”) and stirring with a stirrer at room temperature for about 1 hour. Spin coating and pre-baking were performed in the same manner as in Example 1 to obtain a photosensitive polyarylate coating film having a film thickness of 8.5 μm. Thereafter, light in the i-line to g-line band was irradiated by an ultraviolet exposure machine. The exposure measured with an illuminometer for the i-line band was 100 mJ / cm ² .
The exposed polyarylate coating film was immersed in 100 g of a developer consisting of TMAH / water / ethanol = 0.1 / 0.9 / 3.0 (weight ratio) at 50 ° C. for a fixed time, and then washed with 100 g of ion-exchanged water for 1 minute. . As a result, a negative image was obtained. The development time at this time was 5 minutes and 9 seconds. The resolution was 15 μm with a line-and-space pattern, and the residual film ratio in the exposed area was 87%. An SEM photograph of this photoresist is shown in FIG.

Example 6
The photosensitive PI coating film obtained by the same operation as in Example 5 was irradiated with light in the i-line to g-line band with a UV exposure machine through a PET photomask. The exposure measured with an illuminometer for the i-line band was 300 mJ / cm ² . Thereafter, development was performed in the same manner as in Example 5. The development time at this time was 6 minutes 54 seconds. The resolution was 10 μm in a line and space pattern, and the residual film ratio was 84%. An SEM photograph of this photoresist is shown in FIG.

Example 7
1.0 g of polyarylate PAr-FL-A (50:50) (m: n = 50: 50 polyarylate in the above chemical formula (Chemical Formula 12), number average molecular weight 14,000) was added to NMP4.8 g and dissolved. Thereafter, 0.2 g of photosensitive agent PC-5 (R) was added and stirred with a stirrer at room temperature for about 1 hour to prepare a photoresist composition. Spin coating and pre-baking were performed in the same manner as in Example 1 to obtain a photosensitive polyarylate coating film having a thickness of 9.2 μm. Thereafter, light in the i-line to g-line band was irradiated by an ultraviolet exposure machine. The exposure measured with an illuminometer for the i-line band was 100 mJ / cm ² .
The exposed polyarylate coating film was immersed in 100 g of a developer consisting of TMAH / water / ethanol = 0.1 / 0.9 / 2.0 (weight ratio) at 50 ° C. for a fixed time, and then washed with 100 g of ion-exchanged water for 1 minute. . As a result, a negative image was obtained. The development time at this time was 10 minutes 43 seconds. The resolution was 15 μm in a line and space pattern, and the remaining film ratio in the exposed area was 68%. An SEM photograph of this photoresist is shown in FIG.

Example 8
The photosensitive PAr coating film (film thickness: 8.8 μm) obtained by the same operation as in Example 7 was exposed by the same method and exposure amount as in Example 7.
After exposure, the film was immersed in 100 g of a developer solution consisting of TMAH / water / ethanol = 0.1 / 0.9 / 3.0 (weight ratio) at 50 ° C. for a fixed time, and then washed with 100 g of ion-exchanged water for 1 minute. As a result, a negative image was obtained. The development time at this time was 8 minutes and 27 seconds. The resolution was 20 μm in a line and space pattern, and the remaining film ratio in the exposed area was 61%. An SEM photograph of this photoresist is shown in FIG.

Example 9
1.0 g of polyarylate PAr-FL-A (20:80) (m: n = 20: 80 polyarylate in the above chemical formula (Chemical Formula 12), number average molecular weight 21,000) was added to NMP4.8 g and dissolved. Thereafter, 0.2 g of photosensitive agent PC-5 (R) was added and stirred with a stirrer at room temperature for about 1 hour to prepare a photoresist composition. Spin coating and pre-baking were performed in the same manner as in Example 1 to obtain a photosensitive polyarylate coating film having a thickness of 10.3 μm. Thereafter, light in the i-line to g-line band was irradiated by an ultraviolet exposure machine. The exposure measured with an illuminometer for the i-line band was 100 mJ / cm ² .
The exposed polyarylate coating film was immersed in 100 g of a developer consisting of TMAH / water / ethanol = 0.1 / 0.9 / 2.0 (weight ratio) at 50 ° C. for a fixed time, and then washed with 100 g of ion-exchanged water for 1 minute. . As a result, a negative image was obtained. The development time at this time was 12 minutes 46 seconds. The resolution was 10 μm in a line and space pattern, and the remaining film ratio in the exposed area was 68%. An SEM photograph of this photoresist is shown in FIG.

Example 10
The photosensitive PAr coating film (film thickness: 8.8 μm) obtained by the same operation as in Example 9 was exposed by the same method and exposure amount as in Example 9.
After exposure, the film was immersed in 100 g of a developer solution consisting of TMAH / water / ethanol = 0.1 / 0.9 / 3.0 (weight ratio) at 50 ° C. for a fixed time, and then washed with 100 g of ion-exchanged water for 1 minute. As a result, a negative image was obtained. The development time at this time was 10 minutes 34 seconds. The resolution was 10 μm in a line and space pattern, and the remaining film ratio in the exposed area was 80%. An SEM photograph of this photoresist is shown in FIG.

Example 11
The photosensitive PAr coating film (film thickness: 10.8 μm) obtained by the same operation as in Example 1 was exposed by the same method and exposure amount as in Example 1.
After exposure, the film was immersed in 100 g of a developer solution consisting of TMAH / water / methanol = 0.1 / 0.9 / 3.0 (weight ratio) at 50 ° C. for a fixed time, and then washed with 100 g of ion-exchanged water for 1 minute. As a result, a negative image was obtained, but some patterns were peeled off or cracked in the fine part. The development time at this time was 6 minutes 25 seconds. The resolution was 25 μm in a line and space pattern, and the remaining film ratio in the exposed area was 84%. An SEM photograph of this photoresist is shown in FIG.

Example 12
A photosensitive PAr coating film (thickness 10.4 μm) obtained by the same operation as in Example 3 was exposed by the same method and exposure amount as in Example 3.
After exposure, the film was immersed in 100 g of a developer solution consisting of TMAH / water / ethanol / NMP = 0.1 / 0.9 / 2.0 / 1.0 (weight ratio) at 50 ° C. for a fixed time, and then washed with 100 g of ion-exchanged water for 1 minute. As a result, a negative image was obtained, but a part of the pattern was peeled off. The development time at this time was 7 minutes 25 seconds. The resolution was 55 μm in a line and space pattern, and the remaining film ratio in the exposed area was 54%. An SEM photograph of this photoresist is shown in FIG.

Example 13
After adding and dissolving 1.0 g of polyarylate (PAr-FL-A (100: 0)), m: n = 100: 0, number average molecular weight 13,000) to NMP4.8 g, Photosensitive agent PC-5 ( R) 0.2 g and PMI 0.2 g were added and stirred for about 1 hour at room temperature with a stirrer to prepare a photoresist formulation. Spin coating and pre-baking were performed in the same manner as in Example 1 to obtain a photosensitive polyarylate coating film having a thickness of 11.5 μm. Thereafter, light in the i-line to g-line band was irradiated by an ultraviolet exposure machine. The exposure measured with an illuminometer for the i-line band was 100 mJ / cm ² .
The exposed polyarylate coating film was immersed in 100 g of a developer consisting of TMAH / water / ethanol = 0.1 / 0.9 / 2.0 (weight ratio) at 50 ° C. for a fixed time, and then washed with 100 g of ion-exchanged water for 1 minute. . As a result, a negative image was obtained. The development time at this time was 9 minutes. The resolution was 20 μm in a line and space pattern, and the remaining film ratio in the exposed area was 60%. An SEM photograph of this photoresist is shown in FIG.

Comparative Example 1
To NMP4.8g, polyarylate (PAr-FL-A (0: 100) from which the unit containing the fluorenyl structure was removed from the polyarylate prepared in Production Example 1, m: n = 0: 100 in the above chemical formula (Chemical Formula 12), After adding 1.0 g of number average molecular weight 31,000) and dissolving, 0.2 g of photosensitizer PC-5 (R) was added and stirred with a stirrer at room temperature for about 1 hour to prepare a photoresist composition. Spin coating and pre-baking were performed in the same manner as in Example 1 to obtain a photosensitive polyarylate coating film having a thickness of 10.1 μm. Thereafter, light in the i-line to g-line band was irradiated by an ultraviolet exposure machine. The exposure measured with an illuminometer for the i-line band was 100 mJ / cm ² .
As a result of immersing the exposed polyarylate coating film in 100 g of developer consisting of TMAH / water / ethanol = 0.1 / 0.9 / 2.0 (weight ratio) at 50 ° C. for 36 minutes and 11 seconds, a negative tendency was observed. Since the unexposed area was not completely dissolved, a satisfactory photoresist could not be obtained. When removed from the developer and washed with 100 g of ion-exchanged water for 1 minute, the remaining film ratio in the exposed area was 85% and the film in the unexposed area remained 9.9%.

Comparative Example 2
The photosensitive PAr coating film (thickness 11.1 μm) obtained by the same operation as in Comparative Example 1 was exposed by the same method and exposure amount as in Example 10.
After exposure, the film was immersed in 100 g of a developer solution consisting of TMAH / water / ethanol = 0.1 / 0.9 / 3.0 (weight ratio) at 50 ° C. for a fixed time, and then washed with 100 g of ion-exchanged water for 1 minute. As a result, a negative image was obtained. The development time at this time was 35 minutes 52 seconds. The resolution was 10 μm in a line and space pattern, and the remaining film ratio in the exposed area was 78%. An SEM photograph of this photoresist is shown in FIG.

Claims (10)

A photoresist composition comprising a polyester-based resin and a photoacid generator, wherein the polyester-based resin has at least one structural formula shown below
(In the formula, X has a molecular weight of 100 or more, and —C (R ⁵ R ⁶ ) — (wherein R ⁵ and R ⁶ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms). Represents a phenyl group or a perfluoroalkyl group having 1 to 3 carbon atoms.), An optionally substituted cycloalkylidene group having 5 to 12 carbon atoms, and an optionally substituted 9,9. '-Fluorenylidene group, 1,8-menthanediyl group which may have a substituent, 2,8-mentanediyl group which may have a substituent, pyrazylidene group which may have a substituent, substituted A phthalidyl group which may have a group, an arylene group having 6 to 12 carbon atoms which may have a substituent, or —C (CH ₃ ) ₂ —ph—C (CH ₃ ) ₂ — (provided that ph represents a phenylene group), and Z has a substituent. Also represents an arylene group or an alkylene group, ^{R 1} and ^{R 2} are each independently a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, aryl having 6 to 12 carbon atoms A group selected from the group of a group, an aryl-substituted alkenyl group having 7 to 13 carbon atoms and a fluoroalkyl group having 1 to 6 carbon atoms, and m and n each independently represents an integer of 0 to 4). A repeating unit represented by (1),
And at least one of the following structural formulas:
(In the formula, Y has a molecular weight of less than 100 and is a single bond, —O—, —CO—, —S—, —SO—, —SO ₂ —, —C (R ⁷ R ⁸ ) — (provided that , R ⁷ and R ⁸ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group or a trifluoromethyl group.), And optionally having 5 to 5 carbon atoms. 7 cycloalkylidene group, an optionally substituted pyraziridene group, or an optionally substituted phenylene group, R ³ and R ⁴ each independently represent a halogen atom, a carbon number It is selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aryl-substituted alkenyl group having 7 to 13 carbon atoms, and a fluoroalkyl group having 1 to 12 carbon atoms. Represents a group, Z represents the same as above, and o and p represent Each independently represents an integer of 0 to 4), and the content (molar ratio) of the repeating unit (1) relative to all the repeating units. Is a 0.10 to 1.00 photoresist composition. The photoresist composition according to claim 1, wherein a content ratio (molar ratio) of the repeating unit (1) to all repeating units is 1.00. The photoresist composition according to claim 1, wherein a content ratio (molar ratio) of the repeating unit (1) to all repeating units is 0.10 to 0.95. The photoresist composition according to claim 1, wherein a content ratio (molar ratio) of the repeating unit (1) to all repeating units is 0.40 to 0.80. The photoacid generator has the following formula
The photoresist composition according to any one of claims 1 to 4, which is a compound represented by the formula (wherein R represents an alkyl group or an aryl group). The carbon number of the alkyl group is 1 to 10, and the aryl group is a phenyl group or an α or β-naphthyl group which may have an alkyl group having 1 to 3 carbon atoms as a substituent. 5. The photoresist composition according to 5. Furthermore, the photoresist composition as described in any one of Claims 1-6 containing an anion regeneration agent. A step of providing a photoresist layer comprising the photoresist composition according to any one of claims 1 to 7 on a substrate, masking with a desired pattern, irradiating the pattern surface with ultraviolet light, and the photo A reaction development image forming method comprising a development step of treating a resist layer with a developer, wherein the developer comprises a solvent containing tetra-substituted ammonium hydroxide, a low molecular alcohol and water. A negative photoresist structure having a photoresist layer formed by the method according to claim 8 on a substrate and having a thickness of 0.1 to 500 μm. The photoresist structure according to claim 9, wherein a relief structure having a desired pattern is formed on the photoresist layer.