JP6922424B2 - Radiation-sensitive composition, radiation-sensitive resin composition, and pattern forming method - Google Patents

Description

The present invention relates to a radiation-sensitive composition or the like, and more particularly to a radiation-sensitive composition or the like capable of forming a fine pattern.

As the next-generation photolithography, lithography using a light source (EUV) with a short wavelength is being actively studied. The resist material is the same as that of the resist for KrF and ArF lithography, and is required to have performance such as transparency with respect to the exposure wavelength, high sensitivity, high plasma etching resistance, and low outgassing. Has been done.

With the miniaturization of the resist pattern, there have been problems that the side wall of the line pattern becomes uneven and the line width of the line pattern is not constant and fluctuates.

A technique for microfabrication by decomposing a resin composition forming a resist from the main chain of a resin has been proposed (Patent Document 1). However, since resin is used to the last, there is a limit to miniaturization. Further, as a countermeasure, a technique of using a small molecule compound as a resist instead of a resin composition has been proposed (Non-Patent Document 1).

Japanese Unexamined Patent Publication No. 2006-8973

Network Polymer Vol. 34, No. 5, p. 272 (2013)

However, in the small molecule compound disclosed here, since heat treatment is required when polymerizing and resisting, an adverse effect on the unexposed portion cannot be ignored, and microfabrication is limited.

An object of the present invention is to provide a radioactive composition capable of further microfabrication and a pattern forming method using the composition.

（式（１）中、Ｒ^１及びＲ^２は、それぞれ独立して、炭素数１〜８の１級あるいは２級アルキル基であり、置換基として炭化水素基、フッ素化アルキル基あるいはケイ素化アルキル基を有していても良い。Ｒ^３及びＲ^４は、それぞれ独立して、炭素数１〜８のアルキル基、またはアリール基であり、Ｒ^３及びＲ^４がアルキル基の場合には、置換基として炭化水素基、フッ素化アルキル基あるいはケイ素化アルキル基を有していても良い。Ｘは炭素数１から１２の２価の炭化水素基を表す。） The present invention has been achieved by:
1. 1. A radiation-sensitive composition containing at least an S compound having a plurality of thiol groups, a plurality of functional groups that undergo a thiol-ene reaction, and an E compound having a structural site represented by the following formula (1).
Equation (1)

(In the formula (1), R ¹ and R ² are independently primary or secondary alkyl groups having 1 to 8 carbon atoms, and are hydrocarbon groups, fluorinated alkyl groups or siliconized alkyl groups as substituents. It may have a group. R ³ and R ⁴ are independently alkyl groups or aryl groups having 1 to 8 carbon atoms, and when R ³ and R ⁴ are alkyl groups, they are substituted. It may have a hydrocarbon group, an alkyl fluorinated group or an alkyl siliconized group as a group. X represents a divalent hydrocarbon group having 1 to 12 carbon atoms.)

2. The radiation-sensitive composition according to 1 above, which contains a photosensitizer.
3. 3. The radiation-sensitive composition according to 1 or 2, wherein the photosensitizer is at least one selected from a photoacid generator, a photopolymerization initiator, and a photobase generator.
4. The radiation-sensitive composition according to the above 1-3, which contains an acid diffusion control agent.

5. (1) A step of applying a radiation-sensitive composition onto a substrate to form a coating film.
(2) A step of irradiating the coating film with radiation to cure it (3) A step of irradiating the cured coating film with radiation having a wavelength different from that of the step (2).
(4) A pattern forming method comprising a step of developing the coating film after irradiation with a developing solution.

（式（２）中、Ｘ，Ｒ^１からＲ^４は、式（１）の場合と同義である。）
７．（１） 感放射線性樹脂組成物を基板上に塗布し塗膜を形成する工程、
（２） 上記塗膜に放射線を照射する工程、
（３） 放射線照射後の上記塗膜を現像液で現像する工程
を有するパターン形成方法。
6. A radiation-sensitive resin composition containing a polymer having a structural portion represented by the following formula (2).

(In equation (2), X, R ¹ to R ⁴ are synonymous with the case of equation (1).)
7. (1) A step of applying a radiation-sensitive resin composition onto a substrate to form a coating film.
(2) The step of irradiating the coating film with radiation,
(3) A pattern forming method comprising a step of developing the coating film after irradiation with a developing solution.

（式（１）中、Ｒ^１及びＲ^２は、それぞれ独立して、炭素数１〜８の１級あるいは２級アルキル基であり、置換基として炭化水素基、フッ素化アルキル基あるいはケイ素化アルキル基を有していても良い。Ｒ^３及びＲ^４は、それぞれ独立して、炭素数１〜８のアルキル基、またはアリール基であり、Ｒ^３及びＲ^４がアルキル基の場合には、置換基として炭化水素基、フッ素化アルキル基あるいはケイ素化アルキル基を有していても良い。Ｘは炭素数１から１２の２価の炭化水素基を表す。） Hereinafter, the present invention will be described in detail. The present invention is not limited to this.
<Radiation-sensitive composition>
The radiation-sensitive composition of the present invention contains at least an S compound having a plurality of thiol groups, and an E compound having a plurality of functional groups that undergo a thiol-ene reaction and a structural site represented by the following formula (1). It is characterized by containing.
Equation (1)

(In the formula (1), R ¹ and R ² are independently primary or secondary alkyl groups having 1 to 8 carbon atoms, and are hydrocarbon groups, fluorinated alkyl groups or siliconized alkyl groups as substituents. It may have a group. R ³ and R ⁴ are independently alkyl groups or aryl groups having 1 to 8 carbon atoms, and when R ³ and R ⁴ are alkyl groups, they are substituted. It may have a hydrocarbon group, an alkyl fluorinated group or an alkyl siliconized group as a group. X represents a divalent hydrocarbon group having 1 to 12 carbon atoms.)

In the present invention, when the S compound and the E compound start the reaction by radiation, for example, ultraviolet rays, a polymerization structure by a thiol-ene reaction is generated, and a resin composition such as a resist is formed. Alternatively, a reaction product of the S compound and the E compound is prepared in advance, and a coating film is formed using the reaction product as a resin composition.

A feature of the present invention is that, conventionally, a product that is then developed with an alkaline aqueous solution to complete a pattern is further irradiated with ultraviolet rays before being developed with an alkaline aqueous solution to illuminate the structural portion of the formula (1) in advance. It decomposes to form a pattern.

In the present invention, since the polymer is formed by the thiol-ene reaction, heating is not required as compared with the conventional invention, and the polymerized structure portion is decomposed, so that the polymer can be miniaturized. Since the resist is decomposed in advance before development with an alkaline aqueous solution of the polymerized structure part, the once cured coating film can be further finely processed, and excessive etching can be avoided, so that the transferability is improved. Excellent fine processing is possible.

<< E compound having a plurality of functional groups that undergo a thiol-ene reaction and a structural site represented by the following formula (1) >>
Examples of the functional group that undergoes a thiol-ene reaction in the present invention include a (meth) acryloyl group, a terminal alkene (vinyl group, allyl group, vinyloxy group, allyloxy group, etc.), and a terminal alkyne. The resin can be polymerized by having a plurality of these functional groups present in one molecule of the E compound. The number of functional groups is preferably 3-5. The types in one molecule may be the same or different.

The structural part represented by the general formula (1) is a structural part that is decomposed by high-energy radiation such as ultraviolet rays, particularly light. Both R1 and R2 are preferably alkyl groups, more preferably methyl groups. It is preferable that R3 and R4 are also alkyl groups at the same time, and further, both are preferably methyl groups. X is preferably an alkylene chain and preferably has 2 to 5 carbon atoms.
The molecular weight of the E compound is 200 or more and 5000 or less, and preferably 3000 or less from the viewpoint of easy decomposition. At the structural site represented by the general formula (1), oxygen and carbon bonds are decomposed.
The content of the E compound in the radioactive composition is 10 to 95 parts by mass and preferably 20 to 90 parts by mass with respect to 100 parts by mass of the total solid content.

化合物２

化合物３

化合物４

Ｘは、化合物３と同義である。 Specific examples of the E compound are given, but the present invention is not limited to these compounds.
Compound 1

Compound 2

Compound 3

Compound 4

X is synonymous with compound 3.

<< S compound having multiple thiol groups >>
The S compound having a plurality of thiol groups of the present invention is not particularly limited as long as it has a plurality of thiol groups and does not have a group to be decomposed by an alkaline aqueous solution, but 2 to 5 thiol groups can be used. It is preferably a compound having, and the molecular weight is preferably 90 or more and 1000 or less from the viewpoint of easiness of decomposition.
The S compound is preferably contained in the radiation-sensitive composition in a ratio of 0.7 to 1.5 mol with respect to the E compound.

As the S compound, either an aliphatic compound or an aromatic thiol compound can be used and is not particularly limited. Specific examples of such a polyfunctional thiol compound include glycol dimercaptoacetate, trimethylolpropanetris (3-mercaptopropionate), trimethylolpropanetris (2-mercaptopropionate), and trimethylol. Propantris (2-mercaptoacetate), pentaerythritol tetrakis (thioglycolate), pentaerythritol tetrakis (2-mercaptoacetate), allyl mercaptan, ethylene glycol dimercaptopropionate, trithiocianulic acid (1,3,5-triazine- 2,4,6-trithiol), 3-dithiolphenyl ether, 1,3-dimethylthiomethylbenzene, pentaerythritol tetrakismercaptopropionate, 1,4-butanedithiol, 1,5-pentanedithiol, 1,6-- Pentandithiol, tetramethylene glycol-bis-mercaptopropionate, 1,6-hexyldiol-bis-mercaptopropionate, pentaerythritol bismercaptopropionate, pentaerythritol trismercaptopropionate, trimethylpropanbis mercaptopropionate Pionate, Trimethylol Propantris mercaptopropionate, Dipentaerythritol Tris mercaptopropionate, Sorbitol Tris mercaptopropionate, Sorbitol tetrakis mercaptopropionate, Sorbitol hexakis mercaptopropionate, Dithioethyl terephthalate, 1,6 One or more selected from the group consisting of -hexanediol dithioethyl ether, 1,5-pentanediol dithioethyl ether, and pentaerythritol-tetra- (β-thioethyl ether) can be mentioned.

<Other additives>
In the present invention, a photosensitizer can be added to sensitize to radiation. Examples of the photosensitizer include a photosensitizer (acid generator, photoinitiator, photobase generator), acid diffusion control agent, sensitizer, cyclic ether compound, surfactant, antioxidant, adhesion aid and the like. Be done.

<Photosensitizer>
Examples of the photosensitizer preferably used in the present invention include a photoacid generator, a photoradical initiator, and a photobase generator. It is desirable to use the photoacid generator, photoradical initiator, and photobase generator in the wavelength basins that do not overlap with each other at the wavelengths to be exposed.

For example, a radical polymerization initiator that generates the most radicals in the vicinity of 365 nm is used, and an acid generator that generates the most acid in the vicinity of 250 to 300 nm, which does not overlap with the vicinity of 365 nm, can be used in combination. By using such a combination, radical cross-linking can be generated by exposure at an exposure wavelength of around 365 nm, and by exposing the obtained cured film at around 250-300 nm, the decomposition reaction is promoted by the generated acid. It becomes possible to do.

≪Photoacid generator≫
The acid generator of the present invention refers to a substance that generates an acid by exposure to radiation, for example, ultraviolet rays, and refers to a compound having an acid dissociative group. The generated acid dissociates the acid dissociative group to generate a carboxy group, a hydroxy group, etc., and promotes the polymerization reaction of the S compound and the E compound. It also promotes the decomposition of the polymerized structure of the structural part (1) of the present invention. Since acids are generated by different wavelengths of ultraviolet rays in promoting the polymerization reaction and the decomposition reaction, it is preferable to contain two or more kinds of acid generators. The acid generator may be a small molecule or a polymer.

As the acid generator, known compounds can be used, and examples thereof include onium salt compounds, N-sulfonyloxyimide compounds, sulfonimide compounds, halogen-containing compounds, and diazoketone compounds.

Examples of the onium salt compound include sulfonium salt, tetrahydrothiophenium salt, iodonium salt, phosphonium salt, diazonium salt, pyridinium salt and the like.
Specific examples of the acid generator include compounds described in paragraphs [0080] to [0113] of JP-A-2009-134808, paragraphs [0083] to [0140] of JP-A-2017-679666, and the like. Can be mentioned.

Examples of the acid generated from the acid generator include sulfonic acid, imic acid, amic acid, methidoic acid, phosphinic acid, carboxylic acid and the like. Of these, sulfonic acid, imidic acid, amidoic acid and methidoic acid are preferable.

With respect to 100 parts by mass of the total of the S compound and the E compound, 1 part by mass is preferable, 5 parts by mass is more preferable, and 10 parts by mass is further preferable. On the other hand, as the upper limit, 50 parts by mass is preferable, and 30 parts by mass is more preferable. By setting the content of the photoacid generator in the above range, the sensitivity can be optimized and a cured film having more excellent properties can be formed.

≪Photoradical initiator≫
The photoradical initiator is a compound capable of generating an active species capable of initiating a curing reaction of the polymer component [A] by exposure to radiation such as visible light, ultraviolet rays, far ultraviolet rays, electron beams, and X-rays. ..

Examples of the photoradical initiator include an O-acyloxime compound, an acetophenone compound, an acylphosphine oxide compound, and a biimidazole compound.
The content of the photosensitizer of the present invention is 0.1 to 10 parts by mass, preferably 1 to 5 parts by mass, based on 100 parts by mass of the total of the S compound and the E compound in the radiation-sensitive composition. ..

≪Photobase generator≫
A photobase generator is a compound that generates a base in response to radiation. Examples of the photobase generator include [[(2,6-dinitrobenzyl) oxy] carbonyl] cyclohexylamine, 2-nitrobenzylcyclohexylcarbamate, N- (2-nitrobenzyloxycarbonyl) pyrrolidine, and bis [[(2-2-2-nitrobenzyl) oxycarbonyl). Nitrobenzyl) oxy] carbonyl] hexane-1,6-diamine, triphenylmethanol, O-carbamoyl hydroxyamide, O-carbamoyl oxime, 4- (methylthiobenzoyl) -1-methyl-1-morpholinoetan, (4-morpholino) Benzoyl) -1-benzyl-1-dimethylaminopropane, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone, hexaammine cobalt (III) tris (triphenylmethylborate) and the like can be mentioned. ..

≪Acid diffusion control agent≫
Since the S compound and E compound of the present invention are small molecules, the density of the polymerized resin composition is low, and acid diffusion may become excessive. In order to suppress this, an acid diffusion control agent is added. Is preferable.

As the acid-acetic acid control agent, known ones can be used, and for example, the compounds described in paragraphs [0141] to [0175] [0231] to [0246] of Japanese Patent No. 2017-379666 can be used.
The content of each acid ray control agent is preferably 0.001 to 1 part by mass or less, preferably 0.005 to 0.2 part by mass or less, based on 100 parts by mass of the total of the S compound and the E compound in the radiation-sensitive composition. More preferred.

≪Cyclic ether compound≫
The cyclic ether compound of the present invention can promote polymerization, further increase the hardness of the cured film formed from the radiation-sensitive composition, and increase the radiation sensitivity of the radiation-sensitive resin composition. ..

As the cyclic ether group compound, a compound having two or more epoxy groups (oxylanyl group, oxetanyl group) in the molecule is preferable. Specifically, the cyclic ether compound described in JP-A-2011-257537 can be used.
The content of the cyclic ether group compound is usually 150 parts by mass or less, preferably 0.5 to 100 parts by mass, based on 100 parts by mass of the total of the S compound and the E compound in the radiation-sensitive composition. ~ 50 parts by mass is more preferable, and 10 to 25 parts by mass is further preferable.

≪Sensitizer≫
The sensitizer of the present invention has an action of increasing the amount of acid produced from an acid generator or the like, and has an effect of improving the "apparent sensitivity" of the radiation-sensitive composition of the present invention.
Examples of the sensitizer include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyls, eosin, rosebengal, pyrenes, anthracenes, phenothiazines and the like.

These sensitizers may be used alone or in combination of two or more. The upper limit of the content of the sensitizer is preferably 2 parts by mass, more preferably 1 part by mass, based on 100 parts by mass of the total of the S compound and the E compound in the radiation-sensitive composition.

≪Antioxidant≫
The antioxidant of the present invention is a component that suppresses the breaking of bonds of polymer molecules by capturing radicals generated by exposure or heating, or by decomposing peroxides generated by oxidation.
Specific examples thereof include compounds having a hindered phenol structure, compounds having a hindered amine structure, compounds having an alkyl phosphite structure, compounds having a thioether structure, and the like, and compounds having a hindered phenol structure are preferable. The antioxidant may be used alone or in combination of two or more.
The content of the antioxidant is usually 15 parts by mass or less, preferably 0.1 to 10 parts by mass, based on 100 parts by mass of the total of the S compound and the E compound in the radiation-sensitive composition. 2 to 5 parts by mass is more preferable.

≪Adhesion aid≫
The adhesion aid of the present invention is a component that improves the adhesiveness between a film-forming object such as a substrate and a cured film. Adhesion aids are particularly useful for improving the adhesion between inorganic substrates and cured films. Examples of the inorganic substance include silicon compounds such as silicon, silicon oxide and silicon nitride, and metals such as gold, copper and aluminum, and a functional silane coupling agent is preferable. The content of the adhesion aid is usually 30 parts by mass or less, preferably 0.5 to 20 parts by mass, and 1 to 1 part by mass with respect to 100 parts by mass of the total of the S compound and the E compound in the radiation-sensitive composition. 10 parts by mass is more preferable.

≪Surfactant≫
Examples of the surfactant of the present invention include a fluorine-based surfactant and a silicone-based surfactant. These surfactants may be used alone or in combination of two or more. As the surfactant, the surfactant described in Japanese Patent Application Laid-Open No. 2011-18024 can be used.

The content of the surfactant is usually 3 parts by mass or less, preferably 0.01 to 2 parts by mass, based on 100 parts by mass of the total of the S compound and the E compound in the radiation-sensitive composition. 05 to 1 parts by mass is more preferable.

<Solvent>
The radiation-sensitive composition of the present invention usually contains a solvent. The solvent is one that dissolves at least the S compound and the E compound, and more preferably one that dissolves the acid generator and the acid diffusion control agent.
Specific examples of the solvent include alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, hydrocarbon solvents and the like.

<Method for preparing radiation-sensitive composition>
The radiation-sensitive composition of the present invention is preferably obtained by mixing, for example, an S compound and an E compound with an acid generator, an acid diffusion control agent, a solvent and other optional components in a predetermined ratio, if necessary. The mixed solution can be prepared by filtering the mixture with, for example, a filter having a pore size of about 0.2 μm.

The solid content concentration of the radiation-sensitive composition is preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, still more preferably 1 to 20% by mass.

The radiation-sensitive composition can be used for forming a positive pattern using an alkaline developer and for forming a negative pattern using a developer containing an organic solvent. Of these, the radiation-sensitive composition of the present invention can exhibit higher resolution when used for forming a negative pattern using a developing solution containing an organic solvent.

（式（２）中、Ｘ，Ｒ^１からＲ^４は、式（１）の場合と同義である。）
本発明でパターン形成する場合、Ｓ化合物およびＥ化合物から形成する場合、Ｓ化合物およびＥ化合物をあらかじめの反応させた樹脂組成物として使用し感放射性樹脂組成物としてパターンを形成する場合を挙げることができる。 <Radiation-sensitive resin composition>
In the radiation-sensitive composition of the present invention, the S compound and the E compound are polymerized to form a resin such as a resist, and in particular, a radiation-sensitive composition containing a polymer having a structural site represented by the general formula (2). It is preferably a sex resin composition.

(In equation (2), X, R ¹ to R ⁴ are synonymous with the case of equation (1).)
In the case of forming a pattern in the present invention, there are cases where the pattern is formed from the S compound and the E compound, and cases where the S compound and the E compound are used as a resin composition in which the S compound and the E compound are reacted in advance to form a pattern as a radioactive resin composition. can.

<Pattern formation method>
The pattern forming method of the present invention is characterized by having the following four steps.
(1) A step of applying a radiation-sensitive composition onto a substrate to form a coating film.
(2) A process of irradiating the coating film with radiation to cure it.
(3) A step of irradiating the cured coating film with radiation having a wavelength different from that of the step (2).
(4) Step of developing the coating film after irradiation with a developing solution

The pattern forming method includes a step of forming a coating film (hereinafter, also referred to as a “coating film forming step”), a step of irradiating the coating film with radiation to cure it (hereinafter, also referred to as an “exposure step”), and a cured coating film. A step of irradiating radiation having a wavelength different from that of the "exposure step" (hereinafter, also referred to as "decomposition step") and a step of developing the coating film after irradiation with a developing solution (hereinafter, also referred to as "development step"). To be equipped. In the pattern forming method of the present invention, the coating film is formed by the radiation-sensitive composition of the present invention.

According to the pattern forming method of the present invention, since the radiation-sensitive composition of the present invention described above is used, a pattern having excellent resolution can be formed. Hereinafter, each step will be described.

≪Coating film forming process≫
In this step, a coating film is formed by the radiation-sensitive composition of the present invention. Examples of the substrate on which the coating film is formed include a silicon wafer and a wafer coated with aluminum. A coating film is formed by applying the radiation-sensitive composition of the present invention on this substrate.

The method for applying the radiation-sensitive composition of the present invention is not particularly limited, and examples thereof include known methods such as a spin coating method. When applying the radiation-sensitive composition of the present invention, the amount of the radiation-sensitive composition of the present invention to be applied is adjusted so that the coating film to be formed has a desired thickness. After applying the radiation-sensitive composition of the present invention on a substrate, soft baking (hereinafter, also referred to as “SB”) may be performed to volatilize the solvent. The lower limit of the SB temperature is preferably 30 ° C., more preferably 50 ° C.

The upper limit of the temperature is preferably 200 ° C., more preferably 150 ° C. As the lower limit of the SB time, 10 seconds is preferable, and 30 seconds is more preferable. The upper limit of the time is preferably 600 seconds, more preferably 300 seconds.
The average thickness of the coating film is preferably 10 to 1000 nm, more preferably 20 to 200 nm.

≪Exposure process≫
In this step, the coating film formed in the coating film forming step is exposed. In some cases, this exposure is performed by irradiating radiation through an immersion exposure solution such as water and a mask having a predetermined pattern.

As the immersion exposure liquid, a liquid having a refractive index larger than that of air is usually used. Specific examples thereof include pure water, long-chain or cyclic aliphatic compounds and the like. With the immersion exposure liquid passing through, that is, with the immersion exposure liquid filled between the lens and the coating film, radiation is irradiated from the exposure apparatus, and the coating film is applied through a mask having a predetermined pattern. To expose.

The radiation is appropriately selected from visible light, ultraviolet rays, far ultraviolet rays, X-rays, charged particle beams, etc., depending on the type of radiation-sensitive acid generator used, and has a wavelength of 200 to 500 nm. It is preferably light. In particular, it is preferably 365 nm.

The exposure conditions such as the exposure amount can be appropriately selected according to the composition of the resist composition for immersion exposure, the type of additive, and the like, but the exposure amount is 100 J / m2 or more and 6,000 J /. It is preferably m2 or less, and more preferably 500 J / m2 or more and 2,000 J / m2 or less.
This exposure amount is a value obtained by measuring the intensity of radiation at a wavelength of 365 nm with an illuminometer (“OAI model 356” manufactured by OAI Optical Associates).

≪Disassembly exposure process≫
The present invention is characterized by having a step of decomposing a polymerized resin by radiation having a wavelength different from that of the exposure step once the cured product is cured.
The reaction product of the S compound and the E compound in the present invention exhibits radical polymerizable properties in the compound, and the acrylic group is crosslinked by the radical generated from the radical generator in the first exposure to form a cured film. The reaction product of the S compound and the E compound has a site that is decomposed by an acid or a base. Therefore, by exposing the cured film by the second exposure, the acid (or base) generated from the acid generator (or base generator) existing in the film serves as a catalyst, and the reaction between the S compound and the E compound becomes a catalyst. Some chemical bonds in the substance are broken, and the entire cured film is decomposed.

≪Post-exposure bake≫
The exposed coating film is heat-treated (hereinafter, also referred to as “post-exposure bake (PEB)”). With this PEB, the dissociation reaction of the acid dissociative group can proceed smoothly.
The heating conditions of PEB are appropriately adjusted by the compounding composition of the radiation-sensitive composition, but the temperature of PEB is preferably 30 to 200 ° C., more preferably 50 to 150 ° C., and even more preferably 60 to 120 ° C. The PEB time is preferably 10 to 600 seconds, more preferably 30 to 300 seconds.

Further, in order to maximize the potential of the radiation-sensitive composition, for example, as disclosed in Japanese Patent Application Laid-Open No. 6-12452, Japanese Patent Application Laid-Open No. 59-93448, etc., it is organic on the substrate used. It is also possible to form a system-based or inorganic-based antireflection film. Further, in order to prevent the influence of basic impurities and the like contained in the environmental atmosphere, a protective film may be provided on the coating film, for example, as disclosed in Japanese Patent Application Laid-Open No. 5-188598.

In the present invention, the curing rate is high due to the thiol-ene reaction, and the adverse effect of the heat treatment on the unexposed portion can be minimized. Can be applied.

≪Development process≫
In this step, the coating film exposed in the above exposure step is developed. Examples of the developing solution used for this development include an alkaline aqueous solution (alkaline developing solution), a solution containing an organic solvent (organic solvent developing solution), and the like. As a result, a predetermined resist pattern is formed.

Examples of the alkaline developing solution include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, and methyldiethylamine. , Ethyldimethylamine, Triethanolamine, Tetramethylammonium Hydroxide (TMAH), Pyrol, Piperidine, Colin, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo- [4 .3.0] Examples thereof include an alkaline aqueous solution in which at least one alkaline compound such as -5-nonene is dissolved.
Among these, the TMAH aqueous solution is preferable, and the 2.38 mass% TMAH aqueous solution is more preferable.

Examples of the organic solvent developing solution include organic solvents such as hydrocarbon solvents, ether solvents, ester solvents, ketone solvents and alcohol solvents, and solutions containing organic solvents. Examples of the organic solvent include one or more of the solvents exemplified as the solvent of the above-mentioned radiation-sensitive composition.

Among these, ester-based solvents and ketone-based solvents are preferable. As the ester solvent, an acetate ester solvent is preferable, and n-butyl acetate is more preferable. As the ketone solvent, a chain ketone is preferable, and 2-heptanone is more preferable.

The content of the organic solvent in the organic solvent developer is preferably 80% by mass, more preferably 90% by mass, further preferably 95% by mass, and particularly preferably 99% by mass. Examples of the components other than the organic solvent in the organic solvent developer include water, silicone oil and the like.
These developers may be used alone or in combination of two or more. After development, it is generally washed with water or the like and dried.

<Pattern forming method using a radiation-sensitive resin composition>
The present invention is also characterized in that the S compound and the E compound are reacted in advance to form a resin, and after the coating film formation, the above-mentioned decomposition exposure step and subsequent steps are applied.

<Preparation of polymer (a-1)>
In a flask equipped with a cooling tube and a stirrer, 3.81 parts by mass of 2,5-dimethylhexane-2,5-diyldiacrylate (manufactured by Osaka Organic Co., Ltd.), 4.14 parts by mass of potassium carbonate, and 8 parts by mass of tetrahydrofuran were placed. I prepared it. A solution prepared by dissolving 3.75 parts by mass of 4,4'-thiodibenzenethiol (manufactured by Tokyo Kasei) in 16 parts by mass of tetrahydrofuran was added dropwise to this solution at room temperature, and 30 parts by mass of tetrahydrofuran was added after the addition was completed. Then, the mixture was heated to 30 ° C., and the temperature was maintained for 7 hours for stirring. The reaction solution was reprecipitated with ethanol, and the obtained insoluble material was washed with water and dried under reduced pressure to obtain 7.6 parts by mass of the target polymer (a-1). The polystyrene-equivalent mass average molecular weight (Mw) of the polymer (a-1) was 32,000.

［重量平均分子量（Ｍｗ）及び分子量分布（Ｍｗ／Ｍｎ）の測定方法］
以下の合成例で得られた重合体のポリスチレン換算の重量平均分子量（Ｍｗ）及び分子量分布（Ｍｗ／Ｍｎ）は、以下の条件で測定した。
・測定方法：ゲルパーミエーションクロマトグラフィー（ＧＰＣ）法
・標準物質：ポリスチレン換算
・装置 ：東ソー社の「ＨＬＣ−８２２０」
・カラム ：東ソー社のガードカラム「ＨＸＬ−Ｈ」、「ＴＳＫ ｇｅｌ Ｇ７０００ＨＸＬ」、「ＴＳＫ ｇｅｌ ＧＭＨＸＬ」２本、及び「ＴＳＫ ｇｅｌ Ｇ２０００ＨＸＬ」を順次連結したもの
・溶媒 ：テトラヒドロフラン
・サンプル濃度：０．７質量％
・注入量 ：７０μＬ
・流速 ：１ｍＬ／ｍｉｎ Polymer (a-1)

[Measurement method of weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn)]
The polystyrene-equivalent weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the polymers obtained in the following synthetic examples were measured under the following conditions.
-Measurement method: Gel permeation chromatography (GPC) method-Standard substance: Polystyrene conversion-Device: Tosoh's "HLC-8220"
-Column: Tosoh's guard columns "HXL-H", "TSK gel G7000HXL", "TSK gel GMHXL", and "TSK gel G2000HXL" are connected in sequence.-Solvent: tetrahydrofuran-Sample concentration: 0.7 mass%
・ Injection amount: 70 μL
・ Flow velocity: 1 mL / min

<Preparation of Radiation Sensitive Resin Composition (A-1): Example>
100 parts by mass of the polymer (a-1), 3 parts by mass of N-hydroxynaphthalimide-trifluoromethanesulfonic acid ester as an acid generator, and Polyflow No95 (manufactured by Kyoeisha Chemical Co., Ltd.) 0.1 as a surfactant. By adding parts by mass, adding propylene glycol monomethyl ether acetate as a solvent so that the solid content concentration becomes 15% by mass, and then filtering with a millipore filter having a pore size of 0.5 μm, a radiation-sensitive resin composition ( A-1) was prepared.

<Preparation of Radiation Sensitive Resin Composition (A-2): Examples>
Similar to the polymer (a-1), 2,5-dimethylhexane-2,5-diyldiacrylate (manufactured by Osaka Organic Co., Ltd.) 0.74 parts by mass, 9,9-bis [4- (2-acryloyloxyethoxy) ) Phenyl] Fluorene (Shin-Nakamura Kagaku, A-BPEF) is polymerized to obtain a polymer (a-2), which is used to obtain a radiation-sensitive resin in the same manner as the radiation-sensitive resin composition (A-1). The composition (A-2) was prepared.

<Preparation of Radiation Sensitive Resin Composition (A-3): Comparative Example>
A polymer (a-3) having no structural site of the formula (2) of the present invention is polymerized in the same manner as the polymer (a-1), and this polymer (a-3) is used for radiation sensitivity. A radiation-sensitive resin composition (A-3) was prepared in the same manner as the resin composition (A-1).

Polymer (a-3)

<Preparation of Radiation Sensitive Composition (B-1): Example>
100 parts by mass of E compound 3, 5 parts by mass of triphenylsulfonium triflate as an acid generator, etanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazole-3-yl]-, 1- (O-acetyloxime) (BASF, IrgOXE-02) 10 parts by mass, 4-dimethylaminopyridine 0.01 parts by mass as an acid diffusion control agent,
After adding 0.1 part by mass of Polyflow No. 95 (manufactured by Kyoeisha Chemical Co., Ltd.) as a surfactant and adding propylene glycol monomethyl ether acetate as a solvent so that the solid content concentration becomes 15% by mass, the pore size is 0. A radiation-sensitive composition (B-1) was prepared by filtering with a 5 μm millipore filter.

<Preparation of Radiation Sensitive Composition (B-2): Comparative Example>
(B-2) was prepared in the same manner as the radiation-sensitive tree (B-1) by using 1,4-butanediol diacrylate instead of the E compound portion 3 of the present invention.

<Evaluation>
The prepared radiation-sensitive resin composition and radiation-sensitive composition were used and evaluated according to the following evaluation method. The evaluation results are shown in Table 1.

<Patterning of radiation-sensitive resin composition>
[Patterning of A-1]
A radiation-sensitive resin composition (A-1) was applied onto a silicon wafer using a spin coater, and then prebaked on a hot plate at 90 ° C. for 2 minutes to form a coating film having a film thickness of 1.0 μm. The obtained coating film was irradiated with ultraviolet rays of 313 nm by a mercury lamp through a pattern mask having a line-and-space pattern having a width of 10 μm. Then, after baking on a hot plate at 85 ° C. for 30 seconds, development treatment was performed at 25 ° C. for 60 seconds using a 2.38% tetraammonium hydroxide aqueous solution. At this time, a line-and-space pattern having a width of 10 μm could be formed, and the patterning performance was good. Even if the coating film was once made of resin, a pattern could be formed by subsequent irradiation with ultraviolet rays.

[Patterning of A-2]
In the patterning of the radiation-sensitive resin composition (A-1), (A-2) was used instead of the radiation-sensitive resin composition (A-1), and the same evaluation was performed. As a result, a line having a width of 10 μm was used. -And-space patterns could be formed, and the patterning performance was good.

[Patterning of A-3]
In the patterning of A-1, when (A-3) was used instead of the radiation-sensitive resin composition (A-1) and the same evaluation was performed, a line-and-space pattern having a width of 10 μm could be formed. It was bad.

<Patterning of radiation-sensitive composition>
[Pre-curing of B-1 before patterning]
A radiation-sensitive composition (B-1) was applied onto a silicon wafer using a spin coater, and then prebaked on a hot plate at 90 ° C. for 1 minute to form a coating film having a film thickness of 1.0 μm. The obtained coating film was irradiated with light having a wavelength of 365 nanometers. Then, it was baked on a hot plate at 150 ° C. for 5 minutes and then immersed in propylene glycol monopropyl ether at room temperature for 3 minutes. At this time, the change in the film thickness of the coating film before immersion and the film thickness of the coating film after immersion was less than 0.1 μm, and the curing performance was good.

[Patterning of B-1]
A radiation-sensitive composition (B-1) was applied onto a silicon wafer using a spin coater, and then prebaked on a hot plate at 90 ° C. for 1 minute to form a coating film having a film thickness of 1.0 μm. The resulting coating was irradiated with light of a wavelength of 365 nanometers and then baked on a hot plate at 150 ° C. for 5 minutes. The obtained pre-patterned cured film was irradiated with ultraviolet rays having a wavelength of 313 nm through a pattern mask having a line-and-space pattern having a width of 10 μm. Then, after baking on a hot plate at 150 ° C. for 3 minutes, development treatment was performed at 25 ° C. for 100 seconds using a 2.38% tetraammonium hydroxide aqueous solution. At this time, a line-and-space pattern having a width of 10 μm could be formed, and the patterning performance was good.

[Pre-curing of B-2 before patterning]
In the pre-patterning curing of B-1, when (B-2) was used instead of the radiation-sensitive resin composition (B-1) and the same evaluation was performed, the film thickness and immersion of the coating film before immersion were performed. The change in film thickness of the subsequent coating film was less than 0.1 μm, and the curing performance was good.
[Patterning of B-2]
In the patterning of B-1, when (B-2) was used instead of the radiation-sensitive resin composition (B-1) and the same evaluation was performed, a line-and-space pattern having a width of 10 μm could be formed. It was bad.

As described above, it has been found that the pattern formation using the compound having the structural portion of the present invention enables further microfabrication of the polymer once cured.

Claims (1)

Raw material composition of a radiation-sensitive composition containing at least an S compound having a plurality of thiol groups, a plurality of functional groups that undergo a thiol-ene reaction, and an E compound having a structural site represented by the following formula (1). Things .
Equation (1)

(In the formula (1), R ¹ and R ² are independently primary or secondary alkyl groups having 1 to 8 carbon atoms, and are hydrocarbon groups, fluorinated alkyl groups or siliconized alkyl groups as substituents. It may have a group. R ³ and R ⁴ are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an aryl group, and when R ² and R ⁴ are alkyl groups. May have a hydrocarbon group, a fluorinated alkyl group or a siliconized alkyl group as a substituent. X represents a divalent hydrocarbon group having 1 to 12 carbon atoms.)