JPH05265213A - Radiation sensitive resin composition - Google Patents

Abstract

PURPOSE:To enhance sensitivity and resolution, refine pattern profile, and improve developability, film persistence, and adhesiveness by containing a specified polymer, and a compound producing acid by radiation irradiation. CONSTITUTION:A polymer having a structure, in which a part or all of hydrogen atoms of a phenolic hydroxyl group in a polymer (phenolic polymer) possessing phenolic hydroxyl group are substituted by a group expressed by means of a formula, and a compound (a radiation sensitive acid generating agent) producing acid by radiation irradiation are contained in a resin composition. In the formula, R<a> represents a hydrogen atom or an alkyl group having 1-4 carbons, and R<b> represents an alkylene group having 2-4 carbons. Accordingly the positive type radiation sensitive resin composition is effectively sensitive to the bright line spectrum of a mercury lamp (wave length 254nm), far excimer laser such as ultraviolet rays (wave length 248nm), synchrotron radiation such as X-rays, charged particle beam such as electron beam, and the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive-type radiation-sensitive resin composition which is particularly useful as a resist for ultrafine processing which is sensitive to various radiations including deep ultraviolet rays such as excimer laser.

[0002]

2. Description of the Related Art In the field of microfabrication represented by the manufacture of integrated circuit elements, miniaturization of the processing size in lithography is progressing in order to obtain higher integration, and in recent years, the size of 0.5 μm or less has been achieved. There is a need for a technique capable of performing fine processing with good reproducibility. Therefore, even in the resist used for fine processing, 0.5μ
It is necessary to form a pattern with a size of m or less with high precision, but with the conventional method using visible light (wavelength 700 to 400 nm) or near-ultraviolet (wavelength 400 to 300 nm), a fine pattern of 0.5 μm or less can be formed with high accuracy. Is extremely difficult to form. Therefore, shorter wavelength (wavelength 3
Lithography utilizing radiation of 100 nm or less) has been studied. Radiation of such a short wavelength includes the emission line spectrum of a mercury lamp (wavelength 254 nm) and KrF.
Far-ultraviolet rays typified by excimer lasers (wavelength 248 nm), X-rays typified by synchrotron radiation, charged particle beams typified by electron beams, and the like. Of these, lithography using excimer lasers is particularly important. Due to its high output and high efficiency characteristics, it is attracting attention as a "trump card" for fine processing. Therefore, with respect to the resist used for lithography, a fine pattern of 0.5 μm or less can be formed with high sensitivity and high resolution by deep ultraviolet rays such as excimer laser, and the pattern profile is good.
It is required to have excellent developability (no scum and no development residue during development), residual film property (no film loss during development), and adhesiveness (resist pattern does not peel off during development). As a resist suitable for deep ultraviolet rays, a “chemically amplified resist” is drawing attention. This resist generates an acid by irradiation with radiation (hereinafter, referred to as "exposure"), and heats the resist after exposure (hereinafter, referred to as "post-exposure baking") to form a resist by using the acid as a catalyst. Various chemical reactions occur in the radiation-irradiated region, thereby causing a difference in solubility in a developing solution between a radiation-irradiated portion and a non-irradiated portion to form a pattern. However, conventional chemically amplified resists generally have good sensitivity, but insufficient stability, and therefore, performance is affected by, for example, a time between exposure and baking or a difference in heating temperature after exposure. Changes significantly,
There were problems such as not being practical. In addition, JP-A-64-
No. 88538 discloses (i) a negative photoresist mainly composed of polyphenol, a polyfunctional vinyl ether compound and a photopolymerization initiator, and (ii) a component obtained by modifying the phenolic hydroxyl group of the polyphenol with a vinyl ether group or the like and a cationic photopolymer. Negative photoresists containing a polymerization initiator as a main component have been proposed, but these resists have a vinyl ether group introduced into a polyfunctional vinyl ether compound or polyphenol that is cross-linked and polymerized by exposure,
As a result, the exposed region becomes insoluble in the aqueous alkaline developer, and is a chemically amplified negative resist.

[0003]

Therefore, an object of the present invention is to provide a chemically amplified resist which has high sensitivity and high resolution, has a good pattern profile, and is excellent in developability, residual film property, adhesiveness and the like. The present invention is to provide a novel positive type radiation sensitive resin composition.

[0004]

According to the present invention, the above object is to provide a polymer containing a phenolic hydroxyl group (hereinafter, referred to as
It is called "phenolic polymer". In (), some or all of the hydrogen atoms of the phenolic hydroxyl group in () are substituted with a group represented by the following formula (1) (hereinafter referred to as "polymer (A)"), and radiation. And a compound capable of generating an acid upon irradiation (hereinafter referred to as “radiation-sensitive acid generator”).

(Wherein R ^a is a hydrogen atom or a carbon number of 1 to 4)
Is an alkyl group, and R ^b is an alkylene group having 2 to 4 carbon atoms. )

The present invention will be specifically described below, but the purpose, constitution and effect of the present invention will be clarified. Examples of the polymer (A) used in the present invention include those having at least one monomer unit represented by the following formulas (2) to (5).

[0006]

[Chemical 2]

[0007]

[Chemical 3]

[0008]

[Chemical 4]

[0009]

[Chemical 5]

[In the formulas (2) to (5), R ¹ represents a hydroxyl group or a group represented by the formula (1), and R ² represents a hydrogen atom, a hydroxyl group, an alkyl group, an alkoxy group or the formula (1).
At least a part of the plurality of R ¹ and R ² present in the polymer (A) is a group represented by the formula (1), and each R ³ is a hydrogen atom or an alkyl group. Indicates. In the formulas (2) to (5), the alkyl group for R ² is preferably a group having 5 or less carbon atoms such as a methyl group, an ethyl group, a propyl group and a butyl group, and an alkoxy group is a methoxy group, Those having 5 or less carbon atoms such as an ethoxy group, a propoxy group and a butoxy group are preferable. In addition, R ³
The alkyl group in is preferably one having 5 or less carbon atoms as in the case of R ² .

Particularly preferable units among the above-mentioned monomer units are those represented by the following formulas (5) to (7).

[0012]

[Chemical 5]

[0013]

[Chemical 6]

[0014]

[Chemical 7] [R ^{1 to} R ³ in Formulas (5) to (7) have the same meanings as described above. ].

The polymer (A) in the present invention can also consist of only one monomer unit having a group in which the hydrogen atom of the phenolic hydroxyl group is substituted with the group represented by the formula (1), Two or more monomer units having a group in which the hydrogen atom of the phenolic hydroxyl group is substituted with a group represented by the formula (1) may be randomly bonded, and a unit other than the above monomer units (Hereinafter referred to as “other monomer unit”), for example, styrene, vinyl alcohol,
Units such as acrylic acid, methacrylic acid, maleic anhydride, maleic acid and fumaric acid may be further bound. The content of the other monomer unit in the case of the polymer (A) to which the other monomer unit is bonded cannot be unconditionally determined by the chemical structure of the monomer unit, but is usually 50 mol%. It is below, preferably 30 mol% or below.

Most preferred polymer (A) in the present invention
Is a polymer in which some of the hydrogen atoms of the phenolic hydroxyl group in poly (vinylphenol) have been replaced with vinyloxyalkyl groups, and some of the hydrogen atoms of the phenolic hydroxyl group in novolac resin have been replaced with vinyloxyalkyl groups. And a polymer containing monomer units of both polymers.

The substitution ratio of the group represented by the formula (1) in the polymer (A) (the ratio of the number of the group represented by the formula (1) to the total number of phenolic hydroxyl groups before the substitution) is determined by the present invention. The resist formed from the radiation sensitive resin composition must be in the range of being a positive type. Therefore, the substitution ratio changes depending on the ratio of the monomer unit containing a phenolic hydroxyl group in the phenolic polymer, the number of phenolic hydroxyl groups in the monomer unit, and the like. That is, for example, when the phenolic polymer is composed of only a monomer unit containing a phenolic hydroxyl group, only part of the hydrogen atoms of the phenolic hydroxyl group is replaced with the group represented by the formula (1), and When the phenolic polymer further contains a monomer unit having no phenolic hydroxyl group,
Depending on the monomer unit composition, some or all of the hydrogen atoms of the phenolic hydroxyl group are replaced with the group represented by the formula (1). The substitution ratio of the group represented by formula (1) in the polymer (A) is usually in the range of 5 to 40% of the hydrogen atoms of the phenolic hydroxyl group, preferably 10 to
35%, more preferably 15 to 30%. Further, according to the present invention, when the substitution ratio is in the range of 20 to 30%, a positive radiation-sensitive resin composition having particularly excellent performance can be obtained. When the substitution rate is less than 5%, the substituted polymer itself is dissolved in an alkali developing solution, which lowers the contrast, and in an extreme case, it becomes difficult to obtain a pattern, and the substitution rate exceeds 40%. Then, the photopolymerization due to the carbon-carbon double bond in the group represented by the formula (1) becomes excessive and the cross-linking bond becomes dominant, so that a negative phenomenon occurs and the positive resist cannot function. ..

The polystyrene-reduced weight average molecular weight (hereinafter referred to as "Mw") of the polymer (A) in the present invention is
Usually 3,000 to 300,000, 5,000 to
It is preferably in the range of 50,000. Mw is 3
If the amount exceeds 0,000, it becomes difficult to apply the positive-type radiation-sensitive resin composition of the present invention onto a substrate such as a silicon wafer, and resist properties such as developability and sensitivity tend to be impaired. Further, when Mw is less than 3,000, heat resistance tends to decrease.

As the method for producing the polymer (A), for example, the protecting group in the polymer obtained by polymerizing a monomer in which a phenolic hydroxyl group is substituted with an appropriate protecting group which does not inhibit the polymerization reaction, is used. , For example, by hydrolysis, it is converted into a free phenolic hydroxyl group, and then reacted with a haloalkyl vinyl ether, vinyl oxyalkyl ester sulfate, vinyl oxyalkyl toluene sulfonate ester, etc. in an alkaline medium to give a hydrogen atom of the phenolic hydroxyl group. Is substituted with a group represented by the formula (1), a hydrogen atom of a free phenolic hydroxyl group of a polymer obtained by monoesterifying a carboxyl group-containing polymer with a divalent or trivalent phenol is represented by the formula: Method of substituting with a group represented by (1), the carboxyl group-containing polymer is water of a phenolic hydroxyl group A method of reacting with a phenoxide having a group in which an atom is substituted with a group represented by the formula (1) to form a phenol ester, and the hydrogen atom of the phenolic hydroxyl group in the novolac resin is treated in the same manner as in the formula (1 And a method of substituting with a group represented by). Other methods can be appropriately selected and implemented depending on the chemical structure of the polymer (A), the monomer composition, and the like.

Examples of the radiation-sensitive acid generator used in the present invention include onium salts, halogen-containing compounds, diazoketone compounds, sulfone compounds, sulfonic acid compounds, nitrobenzyl compounds, and the like. , There are the compounds shown below.

Onium salts: iodonium salts, sulfonium salts, phosphonium salts, diazonium salts, ammonium salts and the like. Preferred onium salts are represented by the following formulas (8) to (10)
Is a compound represented by.

[0022]

[Chemical 8]

[0023]

[Chemical 9]

[0024]

[Chemical 10]

[In the formulas (8) to (10), R ^{4 to} R ⁶ may be the same or different from each other, and a hydrogen atom, an amino group,
Nitro group, cyano group, alkyl group (preferably having 1 carbon atom)
To 4) or an alkoxy group (preferably having 1 to 4 carbon atoms)
X is SbF ₆ , AsF ₆ , PF ₆ , BF ₄ , CF ₃ CO ₂ , ClO ₄ , C
F ₃ SO ₃ ,

[Chemical 11] {Here, R ⁷ is a hydrogen atom, an amino group, an anilino group, an alkyl group (preferably having 1 to 4 carbon atoms) or an alkoxy group (preferably having 1 to 4 carbon atoms). },

[Chemical 12] {Here, each R ⁸ may be the same as or different from each other and is an alkoxy group (preferably having 1 to 4 carbon atoms). },

[Chemical 13] {Here, R ⁹ is a hydrogen atom, an amino group, an anilino group, an alkyl group (preferably having 1 to 4 carbon atoms) or an alkoxy group (preferably having 1 to 4 carbon atoms). } Or

[Chemical 14] Indicates. ]

Particularly preferred onium salts are triphenylsulfonium triflate, triphenylsulfonium hexafluoroantimonate, diphenyliodonium triflate, diphenyliodonium hexafluoroantimonate and the like.

Halogen-containing compounds: haloalkyl group-containing hydrocarbon compounds, haloalkyl group-containing heterocyclic compounds and the like. A preferred halogen-containing compound is represented by the following formula (11)
Alternatively, it is a compound represented by (12).

[Chemical 15] [In the formula (11), R ¹⁰ represents a trichloromethyl group, a phenyl group, a methoxyphenyl group, a naphthyl group or a methoxynaphthyl group. ]

[0028]

[Chemical 16] [In the formula (12), R ^{11 to} R ¹³ may be the same or different from each other and represent a hydrogen atom, a halogen atom, a methyl group, a methoxy group or a hydroxyl group. ]

Particularly preferred halogen-containing compounds are 1,
1-bis (4-chlorophenyl) -2,2,2-trichloroethane, phenyl-bis (trichloromethyl) -s
-Triazine, naphthyl-bis (trichloromethyl)-
Examples include s-triazine.

Diazoketone compound: 1,3-diketo-2
-Diazo compounds, diazobenzoquinone compounds, diazonaphthoquinone compounds and the like. Preferred diazoketone compounds are
It is a compound represented by the following formulas (13) to (17).

[Chemical 17] [In the formula (13), R ¹⁴ and R ¹⁵ may be the same or different from each other, and an alkyl group (preferably having a carbon number of 1 to
4) or a substituted or unsubstituted aryl group (preferably having 6 to 20 carbon atoms). ]

[0031]

[Chemical 18]

[0032]

[Chemical 19]

[0033]

[Chemical 20] [In the formula (16), R ¹⁶ is

[Chemical formula 22] R ¹⁷ is -CH _2- , -C (CH ₃ ) _2- , -CO- or -SO _2-.
, M is an integer of 1 to 6, n is an integer of 0 to 5, and m +
n = 1 to 6. ]

[0034]

[Chemical 21] {In formula (17), R ¹⁶ , R ¹⁷ , m and n have the same meanings as in formula (16), and R ¹⁸ represents a hydrogen atom or a methyl group. }

Particularly preferred diazoketone compounds are 1,
2-naphthoquinonediazide-4-sulfonyl chloride,
1,2 of 2,3,4,4'-tetrahydrobenzoquinone
-Naphthoquinonediazide-4-sulfonic acid ester,
1,1,1-Tris (4-hydroxyphenyl) ethane 1,2-naphthoquinonediazide-4-sulfonic acid ester, 1,1-bis (3,5-dimethyl-2-hydroxyphenyl) -1- [4 -(4-hydroxybenzyl)
Phenyl] ethane 1,2-naphthoquinonediazide-4
-Sulfonic acid esters and the like.

Sulfone compound: β-ketosulfone, β-
Sulfonyl sulfone and the like. A preferred sulfone compound is a compound represented by the following formula (18).

[Chemical formula 23] [In Formula (18), Y represents -CO- or -SO _2- ,
R ^{19 to} R ²² may be the same or different from each other, represent a halogen atom or an alkyl group (preferably having 1 to 4 carbon atoms), and s is an integer of 0 to 3. ]

Particularly preferred sulfone compounds are 4-trisphenacyl sulfone, mesitylphenacyl sulfone,
Bis (phenylsulfonyl) methane and the like.

Sulfonic acid compounds: alkyl sulfonates, haloalkyl sulfonates, aryl sulfonates, imino sulfonates and the like. Preferred sulfonic acid compounds are compounds represented by the following formulas (19) to (21).

[Chemical formula 24] [In the formula (19), R ²³ and R ²⁶ may be the same or different from each other and represent a hydrogen atom or an alkyl group (preferably having 1 to 4 carbon atoms), and R ²⁴ and R ²⁵ are the same or different from each other. May be a hydrogen atom, an alkyl group (preferably having 1 to 4 carbon atoms) or an aryl group (preferably having 6 carbon atoms).
.About.20). ]

[0039]

[Chemical 25] [In the formula (20), R ²⁷ represents a hydrogen atom or an alkyl group (preferably having 1 to 4 carbon atoms), and R ²⁸ and R ²⁹
May be the same or different from each other and represent an alkyl group (preferably having a carbon number of 1 to 4) or an aryl group (preferably having a carbon number of 6 to 20), or are bonded to each other to form the formula (2
The structural unit of the ring formed with the nitrogen atom in 0) is shown. ]

[0040]

[Chemical formula 26] [In Formula (21), Z represents a fluorine atom or a chlorine atom. ]

Particularly preferred sulfonic acid compounds are benzoin tosylate and tris triflate of pyrogallol.

Nitrobenzyl compound: Nitrobenzyl sulfonate compound, dinitrobenzyl sulfonate compound and the like. A preferred nitrobenzyl compound is represented by the following formula (2
It is a compound represented by 2).

[Chemical 27] [In the formula (22), R ³⁰ represents an alkyl group (preferably having 1 to 4 carbon atoms), R ³¹ represents a hydrogen atom or a methyl group, and R ³² represents

[Chemical 28] {Here, R ³³ is a hydrogen atom or an alkyl group (preferably having 1 to 4 carbon atoms). },

[Chemical 29] {Here, each R ³⁴ may be the same or different, and is an alkoxy group (preferably having 1 to 4 carbon atoms). } Or

[Chemical 30] Is shown and t is an integer of 1-3. ]

Particularly preferred nitrobenzyl compounds are 2
-Nitrobenzyl tosylate, 2,4-dinitrobenzyl tosylate, 4-nitrobenzyl-9,10-diethoxyanthracene-2-sulfonate and the like.

Of these radiation-sensitive acid generators, onium salts and diazoketone compounds are preferred.

The radiation-sensitive acid generators may be used alone or in admixture of two or more, and the compounding amount thereof is the polymer (A).
It is usually 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight.

If desired, various additives can be added to the positive-type radiation-sensitive resin composition of the present invention. Examples of such an additive include a surfactant. The surfactant exhibits an action of improving the coating property, striation, developability of the radiation-irradiated portion after the formation of the dry coating film, etc. of the radiation-sensitive resin composition of the present invention. Examples of such a surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, polyethylene glycol dilaurate, polyethylene glycol distearate. Rate, an organosiloxane polymer under the trade name KP3
No. 41 (manufactured by Shin-Etsu Chemical Co., Ltd.), a polyacrylic No. 41 (trade name) which is an acrylic acid-based or methacrylic acid-based (co) polymer.
75, no. 95 (manufactured by Kyoeisha Yushi Kagaku Kogyo Co., Ltd.), all of which are trade names below
F352 (above, Shin-Akita Kasei), Megafac F17
1, F172, F173 (above, made by Dainippon Ink), Florard FC430, FC431 (above, made by Sumitomo 3M), Asahi Guard AG710, Surflon S-38
2, SC-101, SC-102, SC-103, SC
-104, SC-105, SC-106 (above, manufactured by Asahi Glass) and the like. The content of the surfactant is usually 2 parts by weight or less based on 100 parts by weight of the total amount of the polymer (A) and the radiation-sensitive acid generator.

Further, other additives include antihalation agents, adhesion promoters, storage stabilizers, defoamers and the like.

The positive type radiation sensitive resin composition of the present invention comprises
It contains the above-mentioned polymer (A), a radiation-sensitive acid generator, and various additives to be blended if necessary, but when it is used, it is dissolved in a solvent and then, for example, with a pore diameter of about 0.2 μm. Prepared as a solution by filtering through a filter.

Examples of the solvent used for preparing the solution in the present invention include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol diether. Propyl ether, diethylene glycol dibutyl ether, 2-methoxyethyl acetate, 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, toluene, xylene, methyl ethyl ketone, cyclohexanone, 2-hydroxy The Methyl pionate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl oxyacetate, methyl 2-hydroxy-3-methylbutyrate, 3-methoxybutylacetate, 3-methyl- 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate, 3-methyl-3-methoxybutyl butyrate, ethyl acetate, butyl acetate, methyl acetoacetate, ethyl acetoacetate, methyl-3-methoxypropionate Nate,
Examples thereof include ethyl-3-ethoxypropionate, N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, methyl pyruvate and ethyl pyruvate. These solvents may be used alone or in combination of two or more.

Further, the solvent may contain, if necessary, benzyl ethyl ether, dihexyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, acetonyl acetone, isophorone, caproic acid, caprylic acid, 1-octanol, 1-octane.
Nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate,
γ-butyrolactone, ethylene carbonate, propylene carbonate,
A high boiling solvent such as phenyl cellosolve acetate can also be added.

When a resist film is formed from the positive-type radiation-sensitive resin composition of the present invention, a solution obtained by dissolving in the solvent and filtering the solution is spin-coated, cast-coated, roll-coated or the like. It is applied on a substrate such as a silicon wafer or a wafer covered with aluminum or the like. The solution concentration at that time is usually 5 to 50% by weight as the total solid content concentration. Then, it is partially exposed to form a fine pattern. There is no particular limitation on the radiation used,
For example, the emission line spectrum of a mercury lamp (wavelength 254 nm), far ultraviolet rays such as excimer laser (wavelength 248 nm), X-ray such as synchrotron radiation, charged particle beam such as electron beam, etc. are used. It is selected according to. Also, the irradiation conditions such as the radiation dose are appropriately selected according to the compounding composition of the positive radiation-sensitive resin composition, the type of each additive, and the like. In the present invention, it is preferable to perform a heat treatment after the exposure in order to improve the sensitivity of the resist. The heating condition varies depending on the composition of the positive radiation-sensitive resin composition, the type of each additive, etc., but is usually 30 to 100 ° C, preferably 40 to 80 ° C.

Next, as a developer for the positive-type radiation-sensitive resin composition of the present invention, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propyl is used. Amine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, dimethylethanolamine, triethanolamine, etc., tetramethylammonium hydroxide, tetraethylammonium hydroxide, pyrrole, piperidine, 1,8-diazabicyclo- [5,4 , 0] -7-Undecene, 1,5-diazabicyclo- [4,3,0]-
An alkaline aqueous solution in which 5-nonane or the like is dissolved can be used. In addition, a proper amount of a water-soluble organic solvent (for example, alcohols such as methanol and ethanol) and a surfactant can be added to the developer. When a developing solution composed of an alkaline aqueous solution is used, it is generally washed with water after development.

[0053]

EXAMPLES The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited to these examples. Example 1 176 g (1 mol) of p-t-butoxystyrene monomer dissolved in 700 g of dioxane solvent was treated with azobisisobutyronitrile 1.462 g (0.01 mol) as an initiator at 60 ° C. It was polymerized for 12 hours. The polymerized product was dropped into methanol to precipitate a polymer, and the precipitated polymer was dried overnight in a vacuum dryer kept at 60 ° C.
The obtained polymer has Mw = 39,000, Mw / Mn
(However, Mn is a number average molecular weight) = 1.67, and the yield was 87.5%. 100 g of this polymer was added to 500 g of dioxane with stirring and dissolved. While refluxing this solution under a nitrogen stream, 100 g of 1% by weight sulfuric acid was gradually added dropwise over about 1 hour, and further refluxed for 2 hours.
The t-butoxy group of the polymer was hydrolyzed. The hydrolysis product was dropped into water to precipitate a polymer, and the precipitated polymer was separated by filtration, washed with pure water, and then dried overnight in a vacuum dryer kept at 60 ° C. The yield of the obtained poly (hydroxystyrene) was 81.3%. 54 g (0.45 mol) of this poly (hydroxystyrene) was dissolved in 300 g of acetone, 36.7 g of chloroethyl vinyl ether, 30 g of potassium carbonate and 2 g of potassium iodide were added, and the mixture was reacted under reflux for 6 hours. The reaction product was dropped into water to precipitate a polymer, and the precipitated polymer was dried overnight in a vacuum dryer kept at 40 ° C.
As a result of NMR measurement, 28% of the phenolic hydroxyl groups of the obtained polymer were substituted with vinyloxyethoxy groups. 10 g of this polymer was dissolved in 31.2 g of ethyl 2-hydroxypropionate together with 0.4 g of triphenylsulfonium trifluoromethanesulfonic acid, and then filtered through a filter having a pore size of 0.2 μm to prepare a resist solution. Next, this solution was applied on a silicon wafer and then baked at 50 ° C. for 1 hour using a clean oven to form a resist film having a film thickness of 1.0 μm.
A pattern mask is brought into close contact with the resist film, and a wavelength of 2
After irradiation with a 48 nm excimer laser at 30 mJ · cm ^-2 , post-exposure baking is performed at 50 ° C. for 10 minutes using a clean oven, and then using a 2.0 wt% tetramethylammonium hydroxide aqueous solution for 25 minutes. ° C
Developed for 60 seconds and then washed with water for 30 seconds. As a result, a positive line-and-space pattern of 0.4 μm was formed with a good profile, and its developability, residual film property, adhesiveness, etc. were excellent.

Example 2 An electron beam was applied to the resist film formed in the same manner as in Example 1.
After irradiation with 0 μC · cm ⁻² , post exposure baking, development and washing were performed in the same manner as in Example 1. As a result, 0.3μ
A positive line-and-space pattern of m was formed with a good profile, and the developability, residual film property, adhesiveness, etc. were excellent.

Example 3 A mixture of meta-cresol and para-cresol Novolak resin 54 obtained by polycondensing cresol with formaldehyde.
After dissolving g (0.45 mol) in 300 g of acetone, 36.7 g of chloroethyl vinyl ether, 30 g of potassium carbonate and 2 g of potassium iodide were added, and the mixture was reacted under reflux for 6 hours. Then, the reaction solution was dropped into water to precipitate a polymer, and the precipitated polymer was dried overnight in a vacuum drier kept at 40 ° C. As a result of NMR measurement, the obtained polymer was found to be substituted with 32% vinyloxyethyl groups of phenolic hydroxyl groups. This polymer 10
g was dissolved in 26.4 g of methyl 3-methoxypropionate together with 0.4 g of triphenylsulfonium trifluoromethanesulfonic acid, and then filtered through a filter having a pore size of 0.2 μm to prepare a resist solution. Next, the obtained solution was applied onto a silicon wafer and then baked at 50 ° C. for 1 hour using a clean oven to form a resist film having a film thickness of 1.0 μm. After irradiating the resist film with an electron beam of 20 μC · cm ⁻² , the post-exposure baking, development and washing were performed in the same manner as in Example 1. As a result, a positive type line and space pattern of 0.3 μm is formed with a good profile, and the developability,
The residual film property and adhesiveness were also excellent.

[0056]

As described above in detail, the positive-type radiation-sensitive resin composition of the present invention has a bright line spectrum (wavelength 254 nm) of a mercury lamp, deep ultraviolet rays such as excimer laser (wavelength 248 nm), and synchrotron radiation. Effectively sensitive to charged particle beams such as X-rays and electron beams, 0.5μ
It is possible to stably perform fine processing of m or less, has high sensitivity and high resolution, has a good pattern profile, and is also excellent in developability, residual film property, adhesiveness, and the like. Therefore, it is extremely useful as a resist material for manufacturing highly integrated circuits such as semiconductor devices, which are expected to be further miniaturized in the future.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Takao Miura 2-11-24 Tsukiji, Chuo-ku, Tokyo Japan Synthetic Rubber Co., Ltd.

Claims (1)

[Claims] 1. A part or all of hydrogen atoms of a phenolic hydroxyl group in a polymer containing a phenolic hydroxyl group,
A positive radiation-sensitive resin composition comprising a polymer having a structure substituted with a group represented by the following formula (1), and a compound capable of generating an acid upon irradiation with radiation. [Chemical 1] (Here, R ^a represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ^b represents an alkylene group having 2 to 4 carbon atoms.)