JP4695577B2 - Photosensitive composition and pattern forming method using the same - Google Patents

Description

  The present invention relates to a photosensitive composition capable of alkali development used for fine processing in a manufacturing process of a semiconductor element and the like, and a pattern forming method using the same.

  2. Description of the Related Art Conventionally, in a manufacturing process of electronic components such as LSIs, a fine processing technique using photolithography has been adopted. In this microfabrication technique, a resist solution is first applied on a substrate or the like to form a resist film, and then the obtained resist film is exposed by pattern light or beam scanning, and then subjected to an alkali treatment. A resist pattern is formed by developing with a developer or the like. Subsequently, the exposed substrate or the like using this resist pattern as a mask is etched by RIE to form fine lines and openings, and finally the resist is removed. Accordingly, the resist used here is generally required to have high dry etching resistance. From this point of view, resists containing aromatic compounds have been widely used so far. Specifically, many resists based on alkali-soluble novolak resins and polyhydroxystyrene have been developed. Yes.

  On the other hand, with the high integration of LSIs and the like, the fine processing technology as described above has recently reached a level of 100 nm or less, and such miniaturization is expected to be further promoted in the future. For this reason, the shortening of the wavelength of the light source in photolithography is progressing, and a fine pattern is currently formed by the fifth harmonic of ArF excimer laser light having a wavelength of 193 nm or YAG laser having a wavelength of 218 nm. In such a short wavelength region, the above-described phenol derivative having a benzene ring is less transparent, so a structure in which an alicyclic compound is introduced into polyacrylic acid or a copolymer such as norbornene and maleic anhydride is examined. Has been.

  By the way, in the microwave device and the quantum effect device trial manufacture, finer patterning characteristics of 50 nm or less are required. For example, as reported by Yoshimura et al. (J. Photopolym. Sci. Technol., 10, 629 (1997) (Non-Patent Document 1)), the molecular size of polymer compounds has begun to affect edge roughness. It has become difficult to improve the resolution further with resists based on the polymer compounds as described above.

  On the other hand, in order to obtain high resolution, an EB resist using a cyclic phenol derivative such as calixarene having a low molecular weight and high heat resistance has been reported (J. Photopolym. Sci. Technol., 10, 641 (1997) ( Non-patent document 2)). However, since calixarene has a relatively low sensitivity and uses an organic solvent as a developer, it is contrary to the recent trend of considering the environment.

  Moreover, as an alkali-soluble cyclic phenol derivative, a negative resist using cyclic resorcinol having methylol as a cross-linking agent was presented by Nakayama et al. (Chem. Lett. 1997 (3), 265 (Non-patent Document 3)) Similarly, Kadoda et al. Have proposed a positive resist using an alkali-soluble phenylbenzene derivative (Chem. Lett. 2004 (6), 706 (Non-patent Document 3)). Was not always satisfactory.

Further, Okumoto et al. Have proposed torquesen derivatives as low-molecular compounds with high heat resistance (see Patent Document 1). However, this document does not disclose a specific method for applying a torquesen derivative to a photosensitive composition for pattern formation.
J. Photopolym. Sci. Technol., 10, 629 (1997) J. Photopolym. Sci. Technol., 10, 641 (1997) Chem. Lett. 2004 (6), 706 JP 2003-261473 A

  The present invention has been made in view of the above-described problems of the prior art, and is a photosensitive composition that meets the requirements for miniaturization of the formation pattern and that improves resolution and solves problems such as edge roughness. An object of the present invention is to provide a pattern forming method using this.

In order to solve the above-described problems, the photosensitive composition according to the present invention includes a compound having a torquesen skeleton structure represented by the following general formula (I) (wherein X and R are hydrogen, A monovalent organic group selected from the group consisting of a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aromatic group, and each X and R may be the same or different. Often, l, m and n are each an integer of 1 to 4), and a photoacid generator which generates an acid by the action of ultraviolet rays or ionizing radiation.

Further, the photosensitive composition according to the present invention includes a compound having a torquesen skeleton structure represented by the following general formulas (II) and (III) (wherein X and R are hydrogen, substituted or unsubstituted). A monovalent organic group selected from the group consisting of an alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aromatic group, and each X and R may be the same or different), and It contains a photoacid generator that generates acid by the action of ultraviolet rays or ionizing radiation.

Furthermore, the present invention relates to a compound having a structure of a torquecene skeleton represented by the following general formula (IV) (wherein X and R are hydrogen, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy, A monovalent organic group selected from the group consisting of a group, a substituted or unsubstituted aromatic group, each X and R may be the same or different, and each of l, m and n is 1 to 4; And o, p, and q are each an integer of 1 to 5), and a photosensitive composition characterized by containing a photoacid generator that generates an acid by acting on ultraviolet rays or ionizing radiation .

  Furthermore, in a preferred embodiment of the present invention, the compounds represented by the general formulas (I) to (IV) are composed of alkali-soluble compounds, and some or all of the hydroxy groups in the molecule of the compounds are protected. A photosensitive composition characterized by having a positive photosensitive property.

  Furthermore, in another preferred embodiment of the present invention, the compound represented by the above general formulas (I) to (IV) comprises an alkali-soluble compound, and further contains a compound that reacts with an OH group by an acid catalyst. A photosensitive composition having the following photosensitive properties:

  In the present invention, a photosensitive layer mainly composed of the above-described photosensitive composition is formed on a substrate, and a latent image is patterned by selectively irradiating the photosensitive layer with ultraviolet rays or ionizing radiation. And a pattern forming method characterized by developing the patterned latent image pattern.

  Since the present invention is configured as described above, the present invention has an excellent effect that it can meet the demand for miniaturization of the formation pattern and can solve problems such as improvement in resolution and edge roughness.

  Hereinafter, the present invention will be described based on preferred specific examples.

The photosensitive composition according to the first aspect of the present invention is a compound having a torquesen skeleton structure represented by the following general formula (I) (wherein X and R are hydrogen, a substituted or unsubstituted alkyl group, , A monovalent organic group selected from the group consisting of a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aromatic group, and each X and R may be the same or different, and l, m and n is an integer of 1 to 4), and a photoacid generator that generates an acid by the action of ultraviolet rays or ionizing radiation.

  The torquesen derivative represented by the general formula (I) preferably has a molecular weight of 2000 or less, and more preferably a molecular weight of 1000 or less. If the molecular weight is excessively large, the developability with an aqueous developer may be deteriorated, or the swellability of the film may become excessive.

  The photosensitive composition of the present invention is mainly composed of the compound represented by the general formula (I). The resist film formed by this composition is formed of the compound, and the substituent is decomposed by the acid derived from the compound that generates an acid upon irradiation with ultraviolet rays or ionizing radiation, so that the solubility in an alkaline aqueous solution is increased. It can be developed even with an aqueous developer having a pH of 11 or less, and functions as a positive photosensitive composition. Further, if the molecular weight is low at this time, the swelling property of the film at the time of development can be suppressed, which is more desirable.

上記一般式において、Ｒは、酸により分解する置換基であり、ｔ−ブチルエステル、イソプロピルエステル、エチルエステル、メチルエステル、ベンジルエステルなどのエステル類；テトラヒドロピラニルエーテルなどのエーテル類；ｔ−ブトキシカルボネート、メトキシカルボネート、エトキシカルボネートなどのアルコキシカルボネート類；トリメチルシリルエーテル、トリエチルシリルエーテル、トリフェニルシリルエーテルなどのシリルエーテル類など、イソプロピルエステル、テトラヒドロピラニルエステル、テトラヒドロフラニルエステル、メトキシエトキシメチルエステル、２−トリメチルシリルエトキシメチルエステル、３−オキソシクロヘキシルエステル、イソボルニルエステル、トリメチルシリルエステル、トリエチルシリルエステル、イソプロピルジメチルシリルエステル、ジ−ｔ−ブチルメチルシリルエステル、オキサゾール、３−アルキル１，３−オキサゾリン、４−アルキル−５−オキソ−１，３オキサゾリン、５−アルキル−４−オキソ−１，３−ジオキソランなどのエステル類、ｔ−ブトキシカルボニルエーテル、ｔ−ブトキシメチルエーテル、４−ペンテニロキシメチルエーテル、テトラヒドロピラニルエーテル、テトラヒドロチオピラニルエーテル、３−ブロモテトラヒドロピラニルエーテル、１−メトキシシクロヘキシルエーテル、４−メトキシテトラヒドロピラニルエーテル、４−メトキシテトラヒドロチオピラニルエーテル、１，４−ジオキサン−２−イルエーテル、テトラヒドロフラニルエーテル、テトラヒドロチオフラニルエーテル、２，３，３ａ，４，５，６，７，７ａ−オクタヒドロ−７，８，８−トリメチル−４，７−メタノベンゾフラン−２−イルエーテル、ｔ−ブチルエーテル、トリメチルシリルエーテル、トリエチルシリルエーテル、トリイソプロピルシリルエーテル、ジメチルイソプロピルシリルエーテル、ジエチルイソプロピルシリルエーテル、ジメチルセキシルシリルエーテル、ｔ−ブチルジメチルシリルエーテルなどのエーテル類、メチレンアセタール、エチリデンアセタール、２，２，２−トリクロロエチリデンアセタール、アダマンチルオキシエチル、アダマンチルメトキシエチル、ビシクロノナン３，７−カルボラクチルオキシエチルなどのアセタール類、１−ｔ−ブチルエチリデンケタール、イソプロピリデンケタール（アセトナイド）、シクロペンチリデンケタール、シクロヘキシリデンケタール、シクロヘプチリデンケタールなどのケタール類、メトキシメチレンアセタール、エトキシメチレンアセタール、ジメトキシメチレンオルソエステル、１−メトキシエチリデンオルソエステル、１−エトキシエチリデンオルソエステル、１，２−ジメトキシエチリデンオルソエステル、１−Ｎ，Ｎ−ジメチルアミノエチリデンオルソエステル、２−オキサシクロペンチリデンオルソエステルなどのサイクリックオルソエステル類、トリメチルシリルケテンアセタール、トリエチルシリルケテンアセタール、ｔ−ブチルジメチルシリルケテンアセタールなどのシリルケテンアセタール類、ジ−ｔ−ブチルシリルエーテル、１，３，１′，１′，３′，３′−テトライソプロピルジシロキサニリデンエーテル、テトラ−ｔ−ブトキシジシロキサン−１，３−ジイリデンエーテルなどのシリルエーテル類、ジメチルアセタール、ジメチルケタール、ビス−２，２，２−トリクロロエチルアセタール、ビス−２，２，２−トリクロロエチルケタール、ダイアセチルアセタール、ダイアセチルケタールなどの非環状アセタール類やケタール類、１，３−ジオキサン、５−メチレン−１，３−ジオキサン、５，５−ジブロモ−１，３−ジオキサン、１，３−ジオキソラン、４−ブロモメチル−１，３−ジオキソラン、４，３′−ブテニル−１，３−ダイオキソラン、４，５−ジメトキシメチル−１，３−ダイオキソランなどのサイクリックアセタール類やケタール類、Ｏ−トリメチルシリルシアノヒドリン、Ｏ−１−エトキシエチルシアノヒドリン、およびＯ−テトラヒドロピラニルシアノヒドリンなどのシアノヒドリン類等が挙げられる。これらの置換基は、たとえばメチレンなどの任意の二価の有機基を経て結合してもかまわない。また、それぞれのＲは同一であっても異なっていてもよい。 In addition, when the compound represented by the general formula (I) has a hydroxyl group at a position where a resonance effect is likely to occur after the substituent is decomposed, the solubility in an alkali developer or an aqueous developer is increased. Can do. From such a viewpoint, those represented by the following general formula (II) or (III) are preferable.

In the above general formula, R is a substituent that is decomposed by an acid, and esters such as t-butyl ester, isopropyl ester, ethyl ester, methyl ester, and benzyl ester; ethers such as tetrahydropyranyl ether; t-butoxycarbo , Alkoxy carbonates such as methoxy carbonate, ethoxy carbonate; silyl ethers such as trimethylsilyl ether, triethylsilyl ether, triphenylsilyl ether, isopropyl ester, tetrahydropyranyl ester, tetrahydrofuranyl ester, methoxyethoxymethyl ester, 2-trimethylsilylethoxymethyl ester, 3-oxocyclohexyl ester, isobornyl ester, trimethylsilyl ester, triethyl Ryl ester, isopropyldimethylsilyl ester, di-t-butylmethylsilyl ester, oxazole, 3-alkyl 1,3-oxazoline, 4-alkyl-5-oxo-1,3 oxazoline, 5-alkyl-4-oxo-1, Esters such as 3-dioxolane, t-butoxycarbonyl ether, t-butoxymethyl ether, 4-pentenyloxymethyl ether, tetrahydropyranyl ether, tetrahydrothiopyranyl ether, 3-bromotetrahydropyranyl ether, 1-methoxycyclohexyl ether, 4-methoxytetrahydropyranyl ether, 4-methoxytetrahydrothiopyranyl ether, 1,4-dioxane-2-yl ether, tetrahydrofuranyl ether, tetrahydrothiofuranyl ether 2,3,3a, 4,5,6,7,7a-octahydro-7,8,8-trimethyl-4,7-methanobenzofuran-2-yl ether, t-butyl ether, trimethylsilyl ether, triethylsilyl ether, Ethers such as triisopropylsilyl ether, dimethylisopropylsilyl ether, diethyl isopropylsilyl ether, dimethyl hexyl silyl ether, t-butyldimethyl silyl ether, methylene acetal, ethylidene acetal, 2,2,2-trichloroethylidene acetal, adamantyloxy Acetals such as ethyl, adamantylmethoxyethyl, bicyclononane 3,7-carbolactyloxyethyl, 1-tert-butylethylidene ketal, isopropylidene ketal (acetonide), Ketals such as clopentylidene ketal, cyclohexylidene ketal, cycloheptylidene ketal, methoxymethylene acetal, ethoxymethylene acetal, dimethoxymethylene orthoester, 1-methoxyethylidene orthoester, 1-ethoxyethylidene orthoester, 1,2 -Cyclic orthoesters such as dimethoxyethylidene orthoester, 1-N, N-dimethylaminoethylidene orthoester, 2-oxacyclopentylidene orthoester, trimethylsilylketene acetal, triethylsilylketene acetal, t-butyldimethylsilylketene acetal Silyl ketene acetals such as di-t-butyl silyl ether, 1,3,1 ', 1', 3 ', 3'-tetraisopropyldisiloxy Silyl ethers such as nilidene ether, tetra-t-butoxydisiloxane-1,3-diylidene ether, dimethyl acetal, dimethyl ketal, bis-2,2,2-trichloroethyl acetal, bis-2,2,2 -Acyclic acetals and ketals such as trichloroethyl ketal, diacetyl acetal, diacetyl ketal, 1,3-dioxane, 5-methylene-1,3-dioxane, 5,5-dibromo-1,3-dioxane, Cyclic acetals such as 1,3-dioxolane, 4-bromomethyl-1,3-dioxolane, 4,3′-butenyl-1,3-dioxolane, 4,5-dimethoxymethyl-1,3-dioxolane, Ketals, O-trimethylsilylcyanohydrin, O-1-ethoxyethylsia Hydrin, and O- cyanohydrins such as tetrahydropyranyl Lucia Nohi polyhedrin the like. These substituents may be bonded via any divalent organic group such as methylene. Each R may be the same or different.

  Since the aromatic ring forms a structure sterically fixed by a five-membered ring, the structure itself has high rigidity, entropy change is suppressed, and heat resistance is increased. When the photosensitive composition of the present invention is used as a chemically amplified positive photoresist, a compound in which the substituent R that is decomposed by an acid is substituted with a protecting group that is decomposed by an acid catalyst, and an acid by irradiation with actinic radiation are used. Used in combination with a generated acid generator.

  The protecting groups which are decomposed by the acid-catalyzed reaction here are, in particular, (a) ester groups such as t-butyl ester, isopropyl ester, ethyl ester and methyl ester, (b) ether groups such as t-butyl ether, (c) Acetal groups such as tetrahydropyranyl ether, ethoxyethyl ether, tetrahydrofuranyl ether, ethyl vinyl ether, adamantyloxyethyl, adamantylmethoxyethyl, bicyclononane 3,7-carbolactyloxyethyl, (d) t-butoxycarbonyl (hereinafter, t- Boc), oxycarbonyl groups such as methoxycarbonyl and ethoxycarbonyl, (e) alkylsilyl groups such as trimethylsilyl, (f) silyl ether groups such as trimethylsilyl ether and triethylsilyl ether Etc. is desirable. These substituents may be bonded via any divalent organic group such as methylene.

  Specific examples of such groups include the same groups as those that can be used for the compounds represented by the general formulas (I) to (III).

In addition, in the compound used in the photosensitive composition of the present invention, various organic groups are present in the X position of the structure of the Torquesen skeleton represented by the general formulas (I) to (III). Can be increased by introducing. Specific examples of such an organic group include aliphatic alkyl groups (for example, methyl, ethyl, propyl, pentyl, or hexyl), cyclic aliphatic groups (for example, cyclopentyl, or cyclohexyl), aromatic groups (for example, phenyl, Or naphthyl), heterocyclic groups (eg, pyridyl, thiophenyl, or pyranyl), halogens (eg, fluorine, chlorine, or bromine), nitriles, nitros, carboxyls, alkylsilanes, and derivatives thereof. The following general formula (IV) in which three substituted phenylbenzyl groups are introduced is desirable.

  In the case where the photosensitive composition of the present invention is constituted as a negative photoresist, preferred embodiments thereof include: (a) having an alkali-soluble torquesen skeleton in which many R are hydrogen, and a glassy state at room temperature. A negative photosensitive composition comprising (b) a photoacid generator that generates an acid by ultraviolet rays or ionizing radiation, (c) a crosslinking agent compound that reacts with a hydroxy group (OH) by an acid catalyst, and can do.

In the above composition, the compound of the crosslinking agent that reacts with the hydroxy group (OH) by the acid derived from the compound (b) that generates an acid upon irradiation with ultraviolet rays or ionizing radiation has an alkali-soluble torquesen skeleton, It reacts with a compound in a glassy state at room temperature to produce a chemically cross-linked product, which becomes hardly soluble in an alkaline aqueous developer, thereby functioning as a negative photosensitive composition. Any suitable compound can be used as the compound of such a crosslinking agent. That is, the photosensitive composition of the present invention may contain a cross-linking agent that reacts with the torquesen derivative to reduce the dissolution rate by a reaction using an acid generated by irradiation with ultraviolet rays or ionizing radiation as a catalyst. Specific examples of such a crosslinking agent include the following.

ここでｘは、各単量体成分の配合比を表すものであり、０〜１の任意の数である。

As described above, the photosensitive composition of the present invention contains, as an essential component, a compound that generates an acid upon irradiation with ultraviolet rays or ionizing radiation. As such an acid generator, sulfonyl, iodonium, and other onium salt compounds and sulfonyl esters are preferably used. Preferable specific examples of such an acid generator include the following.

Here, x represents the blending ratio of each monomer component, and is an arbitrary number from 0 to 1.

Here, x represents the blending ratio of each monomer component, and is an arbitrary number from 0 to 1.

Here, Z is an arbitrary substituent such as alkyl, alkoxy, aryl, or halogen, and X ⁺ -is an arbitrary cationic group.

  These acid generators are generally blended in an amount of 0.1 to 3.0% by weight, preferably 0.3 to 1.5% by weight, based on the total weight of the solid components contained in the photosensitive composition. Is done. If the addition amount of the acid generator is less than the above amount, sufficient sensitivity may not be obtained. If the addition amount is more than the above amount, for example, exposure with ArF excimer light may cause The light transmittance of the photosensitive composition at the exposure wavelength may be impaired by light absorption. In addition, in this specification, a solid component refers to the composition remove | excluding the organic solvent component from the photosensitive composition.

  As described above, the photosensitive composition of the present invention comprises (a) a compound having a torquesen skeleton structure having a substituent that is decomposed by an acid, and preferably a glassy state at room temperature, and (b) acid generation. In addition to the above, various additives can be included as necessary. For example, a compound that decomposes by acid catalysis and exhibits water solubility can be added to the photosensitive composition as a dissolution inhibitor. Moreover, in order to reduce the influence of the basic compound in the environment, which is a drawback of the chemically amplified resist, a trace amount of the basic compound can be added. As such a basic compound, any compound can be used as long as the effects of the present invention are not impaired. Specifically, (i) pyridine derivatives such as t-butylpyridine, benzylpyridine, various pyridiniums, and the like. (B) aniline derivatives such as N-methylaniline, N-ethylaniline, N, N′-dimethylaniline, (c) amine compounds such as diphenylamine, N-methyldiphenylamine, and others, (e) Indene derivatives, as well as others. The addition amount of these basic compounds is generally 0.1 to 50 mol%, preferably 1 to 15 mol%, based on the number of moles of the acid generator. If the addition amount of the basic compound is less than this, the effect of adding the basic compound is difficult to appear, and if it is too much, the sensitivity of the photosensitive composition may be lowered.

  The photosensitive composition of the present invention is prepared by dissolving the above-described components generally in an organic solvent and, if necessary, filtering through a membrane filter or the like. As the organic solvent used here, those generally used in this field are used. Specifically, (i) ketones such as cyclohexanone, acetone, ethyl methyl ketone, methyl isobutyl ketone, and others, (b) Cellosolves such as methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, and others, and (c) esters such as ethyl acetate, butyl acetate, isoamyl acetate, γ-butyrolactone, methyl 3-methoxypropionate, and Others can be mentioned. Depending on the type of the photosensitive composition, dimethyl sulfoxide, N, N-dimethylformamide, N-methylpyrrolidinone, anisole, monochlorobenzene, orthodichlorobenzene and others can be used to improve solubility. Furthermore, lactic acid esters such as ethyl lactate, propylene glycol monoethyl acetate and the like can also be used as a low toxicity solvent.

  In addition, the compound (a), acid generator (b), dissolution inhibitor, organic solvent, and others described above as components of the photosensitive composition can be used in combination of two or more as necessary.

The pattern formation method of this invention forms a pattern using the said photosensitive composition, and comprises the following each process. (I) a step of coating the photosensitive composition on a substrate to form a photosensitive layer, (ii) a step of selectively irradiating the photosensitive layer with ultraviolet rays or ionizing radiation, and (iii) the substrate. (Iv) The step of developing the photosensitive layer after the heat treatment step to selectively remove the irradiated region of the photosensitive layer. In the pattern forming method, the development processing is performed with an aqueous developer having a pH of 11 or less.

  As a substrate to which the photosensitive composition of the present invention is applied, any substrate known in the art can be used. Specific examples of such a substrate include a silicon wafer, a doped silicon wafer, a silicon wafer on which various insulating films, electrodes, or wirings are formed, a mask blank, a group III-V such as GaAs or AlGaAs. Compound semiconductor wafers and others can be mentioned. A chromium or chromium oxide deposition substrate, an aluminum deposition substrate, an IBSPG coated substrate, an SOG coated substrate, or a SiN coated substrate can also be used. The method of applying the photosensitive composition to the substrate is also arbitrary, and spin coating, dip coating, doctor blade method, curtain coating, and other methods are used. The applied photosensitive composition is usually heat-dried at 170 ° C. or lower, preferably 70 to 120 ° C., to form a photosensitive layer. Next, the photosensitive layer is subjected to pattern exposure. The exposure method may be one in which exposure is performed through a predetermined mask pattern, or one in which exposure is performed by directly scanning the photosensitive layer with ionizing radiation. Any ionizing radiation can be used as long as the photosensitive composition has a wavelength with sensitivity. Specifically, ultraviolet rays, mercury lamp i-line, h-line, or g-line, xenon lamp light, new ultraviolet UV light (for example, excimer laser light such as KrF or ArF), X-ray, synchrotron orbital radiation (SR) , Electron beams, gamma rays, ion beams, and others can be used.

  Subsequently, heat treatment (baking treatment) is performed as necessary. The heat treatment can be performed by any method known in the art, but is generally performed by heating on a hot plate or in a heating furnace, or infrared irradiation. In the chemically amplified resist composition, the heat treatment is performed to promote the acid catalyst reaction, but the heat treatment is usually performed at 150 ° C. or lower in order to suppress excessive diffusion of the acid.

  Subsequently, the photosensitive layer is developed with an alkali developer. Any developer known in the art can be used as the developer to be used. Specifically, (a) an organic alkaline aqueous solution, for example, a tetramethylammonium hydroxide aqueous solution, a tetraethylammonium hydroxide aqueous solution, or a choline aqueous solution. And (b) inorganic alkaline aqueous solutions such as aqueous potassium hydroxide, aqueous sodium hydroxide, and others. The concentration of the alkali developer is not limited, but is preferably 15% by mol or less in order to increase the difference in dissolution rate between the exposed portion and the unexposed portion of the photosensitive layer, that is, to increase the dissolution contrast. An aqueous developer having a pH of 11 or less can also be used as the alkali developer. Moreover, arbitrary additives can also be added to these developers as necessary. For example, a surfactant can be added to lower the surface tension of the developer, or a neutral salt can be added to activate development. Further, the temperature of the developer is arbitrary, and cold water or hot water can be used.

  The resist pattern of the present invention can be formed by the above steps (i) to (iv), but further steps can be added as necessary. For example, a step of forming a planarization layer before coating a photosensitive layer on a substrate, a step of forming an antireflection layer for reducing the reflection of exposure light, and washing the substrate after development with water or the like A rinsing step for removing a developer, a step of irradiating ultraviolet rays again before dry etching, and the like can be combined with the above steps.

Synthesis Example 1 (Synthesis of 2, 7, 12-trihydroxy torquesen)
5-hydroxy-1-indanone (5.92 g) and paratoluenesulfonic acid (7.6 g) were placed in a three-necked flask and purged with argon. Dehydrated ethylene glycol (80 ml) and toluene (160 ml) were added thereto, and the mixture was stirred for 2 days with refluxing and water separation. After 10.5 ml of water was added, it was confirmed that the reaction solution became deep red and a cloth-like solid was deposited. Then it was cooled and 5% aqueous sodium bicarbonate solution was added. The precipitated crystals were suction filtered and washed with water. The obtained solid is lightly dried and then recrystallized from a mixed solvent of dimethylformamide-pure water (1: 1) to give a yellow-red crystal product (2, 7, 12-trihydroxytorkcene (hereinafter referred to as THTX)). Got.

Synthesis Example 2 (Synthesis of 2,7,12-tritertiary butoxycarbonyloxytorkcene)
2,7,12-Trihydroxytorkcene (1.50 g) was placed in a three-necked flask and purged with argon. Add dehydrated THF (260 ml), dissolve the substrate, add potassium carbonate (5.09 g), 18-crown-6 (6.45 g) and pyrocarboxylic acid ditertiary butyl dicarbonate (7.46 ml) in order. did. And it stirred at 40 degreeC for 1.5 hours. Next, pure water was added and extracted three times with ethyl acetate. The obtained organic layer was concentrated, purified by silica gel column chromatography (developing solvent: ethyl acetate), and further washed with methanol. The obtained solid was suction filtered and dried to obtain a yellow powder product (2, 7, 12-tritertiary butoxycarbonyloxytorkcene (hereinafter referred to as TBOTX)).

Synthesis Example 3 (Synthesis of 5,10,15-tris (4-methoxyphenylmethyl) -2,7,12-tritertiary butoxycarbonyloxytorkcene)
2,7,12-tritertiary butoxycarbonyloxytorkcene (6.50 g) is placed in a three-necked flask and purged with argon. A dehydrated dimethylformamide-tetrahydrofuran mixed solution (500 ml) was added, and the mixture was stirred well to obtain a suspension. The mixture was cooled to 4 ° C., sodium hydride (1.12 g) washed with a small amount of dehydrated hexane was added, and the mixture was stirred until it became clear reddish brown. Paramethoxybenzyl bromide (10.55 g) was added dropwise thereto, and the mixture was stirred for 10 minutes at room temperature. Next, a large amount of ethyl acetate was added, and the solution was washed successively with a dilute oxalic acid aqueous solution and a saturated saline solution. The extracted organic layer was dried over anhydrous sodium sulfate and concentrated. The resulting residue was washed with a small amount of ethyl acetate to give the yellow powder product 5,10,15-tris (4-methoxyphenylmethyl) -2,7,12-tritertiary butoxycarbonyloxytorxene ( (Hereinafter referred to as TMBTBOTX).

Synthesis Example 4 (Synthesis of polyphosphate ester)
Phosphorus pentoxide (50 g) was placed in a three-necked flask and purged with argon. Into this, dehydrated diethyl ether (50 ml) and dehydrated chloroform (50 ml) were added and stirred for 8 hours while refluxing. The precipitate was filtered, and the filtrate was concentrated to obtain a residual yellow viscous liquid product (polyphosphate ester).

Synthesis Example 5 (Synthesis of 2,7,12-trimethoxytorkcene)
5-Methoxy-1-indanone (9.25 g) and polyphosphate ester (21.25 g) were placed in a three-neck flask, purged with argon, and stirred at 140 ° C. for 2 hours under reflux. Next, 50 ml of ethanol was gradually added while cooling the flask, followed by stirring at room temperature for 1 hour. The precipitate was suction filtered, and the precipitate was washed with acetone and collected. A yellow solid product (2,7,12-trimethoxytorkcene) was obtained by vacuum drying at 50 ° C.

Synthesis Example 6 (Synthesis of 5,10,15-tris (4-methoxyphenylmethyl) -2,7,12-trimethoxytorkcene)
2,7,12-Trimethoxytorkcene (6.50 g) is placed in a three-necked flask and purged with argon. Dehydrated dimethylformamide (500 ml) was added and stirred well to make a suspension. The mixture was cooled to 4 ° C., sodium hydride (1.12 g) washed with a small amount of dehydrated hexane was added, and the mixture was stirred until it became clear reddish brown. Paramethoxybenzyl bromide (10.55 g) was added dropwise thereto, and the mixture was stirred for 1 hour at room temperature. Next, a large amount of ethyl acetate was added, and the solution was washed successively with a dilute oxalic acid aqueous solution and a saturated saline solution. The extracted organic layer was dried over anhydrous sodium sulfate and concentrated. The resulting residue was washed with a small amount of ethyl acetate to give a yellow powder product (5,10,15-tris (4-methoxyphenylmethyl) -2,7,12-trimethoxytorkcene).

Synthesis Example 7 (Synthesis of 5,10,15-tris (4-hydroxyphenylmethyl) -2,7,12-trihydroxytorkcene)
Syn-5,10,15-tris (4-methoxyphenylmethyl) -2,7,12-trimethoxytorquecene (3 g) is placed in a three-necked flask and purged with argon. A 30% hydrogen bromide-containing acetic acid solution (500 ml) was added thereto, and the mixture was refluxed for 2 hours. The reaction mixture was poured into a large amount of ice water, and the resulting solid was collected and washed with pure water. The collected solid was dissolved in ethyl acetate and washed twice with pure water, twice with 5% aqueous sodium hydrogen carbonate solution, and again with pure water. The extracted organic layer was dried over anhydrous magnesium sulfate and concentrated to give a yellow powder product (5, 10, 15-tris (4-hydroxyphenylmethyl) -2,7,12-trihydroxytorkcene (hereinafter referred to as THBTHTX). )).

Synthesis Example 8 (Synthesis of 5,10,15-tris (4-hydroxyphenylmethyl) -2,7,12-tritertiary butoxycarbonyloxytorkcene)
Syn-5,10,15-tris (4-hydroxyphenylmethyl) -2,7,12-trihydroxytorkcene (1.50 g) was placed in a three-necked flask and purged with argon. Add dehydrated tetrahydrofuran (50 ml) to it, dissolve the substrate, and add potassium carbonate (5.09 g), 18-crown-6 (6.45 g) and pyrocarboxylic acid ditertiary butyl dicarbonate (7.46 ml) in order. did. And it stirred at 40 degreeC for 1 hour. Next, pure water was added and extracted three times with ethyl acetate. The obtained organic layer was concentrated, purified by silica gel column chromatography (developing solvent: ethyl acetate), and further recrystallized from tetrahydrofuran. The resulting solid was suction filtered and dried to give a yellow powder product (5,10,15-tris (4-hydroxyphenylmethyl) -2,7,12-tritertiary butoxycarbonyloxytorkcene (hereinafter referred to as THBTBOTX). )).

Various torquesen compounds synthesized in this way were blended at the blending ratios shown in Table 1, and dissolved in anisole to prepare resist solutions. Note that 4,4′-ditertiary butylphenyl iodonium triflate is used as the photoacid generator, and 2,6-bis (hydroxymethyl) -4-methylphenol is used as a crosslinking agent when used as a negative resist. It was.

Examples 1-6
The adjusted resist solution shown in Table 1 was applied onto a silicon wafer by spin coating to form a thin film with a thickness of 50 nm to prepare a resist film. The obtained resist film was baked at 110 ° C. for 90 seconds, and then patterned with an electron beam lithography apparatus (HL800D) (electron beam acceleration voltage was 50 keV). After a post-exposure baking process as necessary, development was performed with a 2.38% tetramethylammonium hydroxide (TMAH) aqueous solution. In Examples 1, 4, and 6, negative patterns were used. Then, we obtained each positive pattern.

  The roughness was evaluated by the following line width roughness (LWR) evaluation method. The resist film was drawn with an electron beam and baked and developed with an aqueous TMAH solution to obtain a constant line and space pattern with a line width of 120 nm. The LWR value (3σ value) of the obtained pattern was calculated in the range of 350 nm × 50 nm (ROI).

Synthesis Example 8 (Comparative compound: 1,3,5-tris (4-tertiary butoxycarbonyloxyphenyl) benzene (TBOTPB) synthesis)
1,3,5-Tris (4-hydroxyphenyl) benzene (2 g) was placed in a three-necked flask and purged with argon. Add dehydrated tetrahydrofuran (50 ml) to it, dissolve the substrate, and add potassium carbonate (7.52 g), 18-crown-6 (9.52 g) and pyrocarboxylic acid ditertiary butyl dicarbonate (11.05 ml) in order. did. And it stirred at 40 degreeC for 10 hours. Next, pure water was added and extracted three times with ethyl acetate. The obtained organic layer was concentrated, purified by silica gel column chromatography (developing solvent: ethyl acetate), and recrystallized with a tetrahydrofuran-methanol mixed solvent. The obtained solid was suction filtered and dried to obtain a white powder product (1,3,5-tris (4-tertiarybutoxycarbonyloxyphenyl) benzene).

Comparative Example 1
A reference compound (1,3,5-tris (4-tertiarybutoxycarbonyloxyphenyl) benzene) is dissolved in methyl methoxypropionate, electron beam drawing is performed in the same manner as in Example 1, and further developed with an aqueous TMAH solution. Processing was performed to obtain a pattern.

Comparative Example 2
Partially tertiary butoxycarbonyloxylated polyhydroxystyrene having a molecular weight of 20000 was dissolved in methyl methoxypropionate, and a thin film having a thickness of 50 nm was obtained in the same manner as in Example 1. Further, electron beam drawing and development were performed in the same manner as in Comparative Example 1 to obtain a pattern. The treatment conditions and the results obtained were as shown in Table 2.

  As is clear from the results in Table 2, when pattern formation was performed using the resist of the present invention, development with an alkaline aqueous solution was possible, and excellent resolution with high sensitivity and low roughness was obtained. I understand that

Examples 7-9
The adjusted positive resist solutions 2, 3, and 5 shown in Table 1 were applied onto a silicon wafer by spin coating to form a thin film having a film thickness of 180 nm to prepare a resist film. The obtained resist film was baked at 110 ° C. for 90 seconds, and then exposed entirely with ultraviolet rays, baked, and then developed with a 2.38% tetramethylammonium hydroxide (TMAH) aqueous solution to obtain a remaining film ratio of 50. % Constant value film was obtained. The area of 500 nm x 500 nm on the surface is measured with an AFM measuring device (Nanoscope III, non-contact mode, super sharp silicon chip [SSS-NCH-50] is used for the cantilever), and the area of 250 nm x 250 nm The surface roughness was evaluated with the analysis software attached to the AFM measuring apparatus. The results obtained are as shown in Table 3.

Comparative Example 3
A partially tertiary butoxycarbonyloxylated polyhydroxystyrene having a molecular weight of 20000 was dissolved in methyl methoxypropionate, and a thin film having a thickness of 180 nm was obtained in the same manner as in Example 7. Further, the surface roughness was evaluated in the same manner as in Example 7.

  As apparent from the results in Table 3, it was found that the surface roughness was small when the resist of the present invention was used. Since the surface roughness is considered to correspond to the edge roughness, it can be confirmed again that the roughness is small when the resist of the present invention is used.

Examples 10-15
The adjusted resist solution shown in Table 1 was applied onto a silicon wafer by spin coating to form a thin film with a thickness of 50 nm to prepare a resist film. The obtained resist film was baked at 110 ° C. for 90 seconds, and then subjected to pattern exposure with a KrF excimer laser stepper. After a post-exposure baking treatment as necessary, development was performed with a 2.38% tetramethylammonium hydroxide (TMAH) aqueous solution to obtain a pattern.

  As is clear from the results in Table 4 for reference, when pattern formation is performed using the resist of the present invention, pattern formation by alkali development is possible in all cases. Considering the photosensitive mechanism of the photoacid generator, it can be easily estimated that it is sensitive to EUV light of soft X-rays (13 nm). That is, the resist of the present invention can be applied to future EUV lithography.

Claims (6)

A compound having the structure of a torquecene skeleton represented by the following general formula (I) (wherein X and R are hydrogen, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aromatic group) A monovalent organic group selected from the group consisting of group groups, wherein each X and R may be the same or different, and l, m and n are each an integer of 1 to 4), and A photosensitive composition comprising a photoacid generator that generates an acid by the action of ultraviolet rays or ionizing radiation.

Compounds having the structure of torquesen skeleton represented by the following general formulas (II) and (III) (wherein X and R are hydrogen, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted Or a monovalent organic group selected from the group consisting of unsubstituted aromatic groups, and each X and R may be the same or different), and generates an acid by the action of ultraviolet rays or ionizing radiation A photosensitive composition comprising a photoacid generator.

A compound having a structure of a torquecene skeleton represented by the following general formula (IV) (wherein X and R are hydrogen, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted A monovalent organic group selected from the group consisting of aromatic groups, wherein each X and R may be the same or different; l, m and n are each an integer of 1 to 4; , P and q are each an integer of 1 to 5, and a photoacid generator that generates an acid by the action of ultraviolet rays or ionizing radiation.

  The compound represented by the general formula (I) to (IV) according to any one of claims 1 to 3 comprises an alkali-soluble compound, and a part or all of the hydroxy groups in the molecule of the compound are protected. The photosensitive composition according to claim 1, wherein the photosensitive composition has positive photosensitive characteristics.   The compound represented by the general formulas (I) to (IV) according to any one of claims 1 to 3 comprises an alkali-soluble compound, and further contains a compound that reacts with an OH group by an acid catalyst, thereby forming a negative type. The photosensitive composition according to claim 1, wherein the photosensitive composition has the following photosensitive properties: A photosensitive layer mainly composed of the photosensitive composition according to any one of claims 1 to 5 is formed on a substrate,
Patterning the latent image by selectively irradiating the photosensitive layer with ultraviolet or ionizing radiation;
A pattern forming method comprising developing the patterned latent image pattern.