Compound, method for producing the compound, photosensitive composition containing the compound, method for forming a pattern using the composition, substrate, and method for producing the substrate.

Abstract

The present invention provides cluster compounds that can enable miniaturization of circuit patterns, and photosensitive compositions containing the same. [Solution] The transition metal cluster compound of the present invention is characterized by containing a transition metal atom and a carboxyl ligand represented by the following chemical formula (1). TIFF2026170520000035.tif46170 In the formula, n is an integer from 1 to 3 or from 5 to 6, and X, Y, and Z are each independently selected atoms from C, N, S, O, Si, Ge, P, Se, and Te. If there are multiple Zs, the Zs may be different atoms and may form double bonds with each other. m is an integer from 0 to 8, and R is each independently an organic group or a halogen.

Description

[Technical Field]

[0001] The present invention relates to a transition metal cluster compound suitably used in ultramicrolithography processes such as the manufacturing of ultra-large-scale integrated circuits (ULSIs) and high-capacity microchips, and other photofabrication processes, a method for producing the compound, a photosensitive composition containing the same, a pattern formation method using the photosensitive composition, a substrate, and a method for producing the substrate. [Background technology]

[0002] In the manufacturing process of semiconductor devices, microfabrication is performed using lithography with photoresist compositions. In semiconductor photolithography, following Moore's Law, circuit patterns become smaller as semiconductor devices are miniaturized, and further miniaturization is desired.

[0003] The development of photolithography is largely comprised of the shortening of the wavelength of light sources in exposure equipment and the subsequent development of new photoresists. Photoresists are required to satisfy all three requirements: high resolution, low roughness, and high sensitivity. Conventional resists are photosensitive compositions containing photoacid generators based on organic polymers, and are called chemically amplified resists. These resists proceed with a chemical reaction accompanied by acid diffusion, but the acid diffusion process can cause line edge roughness (LER), resulting in a decrease in resolution, and are therefore considered unsuitable for ultrafine patterns.

[0004] Therefore, in recent years, non-chemically amplified photoresists (hereinafter referred to as metal-containing resists) mainly composed of compounds containing metal elements such as Zn and Sn have been proposed. In metal-containing resists, the metal component itself is a photosensitive material and also functions as a base material. Because it does not involve acid diffusion, it can improve line edge roughness, and is therefore expected to be a next-generation resist material for forming finer pattern structures. In fact, it has been reported that fine patterns can be formed with next-generation exposure equipment using extreme ultraviolet (EUV) light. For example, Patent Documents 1-6 and Non-Patent Documents 1-3 disclose methods for forming resist patterns using extreme ultraviolet (EUV) light or electron beams. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2015-108781 [Patent Document 2] Japanese Patent Publication No. 2001-072716 [Patent Document 3] Japanese Patent Publication No. 2017-173537 [Patent Document 4] Japanese Patent Publication No. 2012-185484 [Patent Document 5] Japanese Patent Publication No. 2021-102604 [Patent Document 6] International Publication No. 2024 / 143204 [Non-patent literature]

[0006] [Non-Patent Document 1] Minoru Toriumi etc.,Proc.SPIE,9779(2016)97790G [Non-Patent Document 2] Lianjia Wu etc.,Proc.SPIE,10957(2019)109570B [Non-Patent Document 3] Neha Thakur etc.,Proc.SPIE,10957(2019)10957D [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] In photolithography, particularly semiconductor photolithography technology, there is a need for photosensitive compositions and pattern formation methods that can achieve further miniaturization of circuit patterns.

[0008] As a result of extensive and intensive studies, the present inventors have found that a compound having a specific structure is suitable for photoresists corresponding to ultra-fine patterns.

[0009] Accordingly, an object of the present invention is to provide a compound capable of realizing miniaturization of circuit patterns, a photosensitive composition containing the same, a pattern forming method using the photosensitive composition, a substrate having a pattern layer obtained by the pattern forming method, and a method for producing the substrate. [Means for Solving the Problems]

[0010] The present invention has the following aspects [1] to

[16] .

[0011] [1]. A transition metal cluster compound comprising a transition metal atom and a carboxy ligand represented by the following chemical formula (1).

[0012] TIFF2026170520000001.tif46170 In the above chemical formula (1), n is an integer of any of 1 to 3, 5 to 6, X, Y, Z are each independently any atom selected from C (carbon), N (nitrogen), S (sulfur), O (oxygen), Si (silicon), Ge (germanium), P (phosphorus), Se (selenium), and Te (tellurium); when a plurality of Z are present, the Zs may be different atoms, and a double bond may be formed between the Zs. m is an integer of any of 0 to 8, and each R is independently an organic group or a halogen.

[0013] [2]. The transition metal cluster compound according to [1], wherein X, Y and Z in the above chemical formula (1) are all carbon, and the bonds between Z and X, between Y and Z, and between Z and Z (when n is 2 or more) are all single bonds.

[0014] [3]. The transition metal cluster compound according to [1] or [2], wherein n=3 in the above chemical formula (1).

[0015] [4]. The transition metal cluster compound according to [3], wherein the carboxy ligand is cyclopentenecarboxylic acid which may have a substituent.

[0016] [5]. The transition metal cluster compound according to any one of [1] to [4], comprising 4 to 12 of the transition metal atoms.

[0017] [6]. The transition metal cluster compound according to any one of [1] to [5], wherein the transition metal atom is any one of titanium, hafnium, and zirconium.

[0018] [7]. A method for producing the transition metal cluster compound according to any one of [1] to [6], the method comprising reacting a compound containing the transition metal atom with a carboxylic acid having a structure of the carboxy ligand in a solution.

[0019] [8]. A photosensitive composition comprising the transition metal cluster compound according to any one of [1] to [6].

[0020] [9]. The photosensitive composition according to [8], further comprising a solvent.

[0021]

[10] . A photosensitive composition comprising the transition metal cluster compound according to any one of [1] to [6] at a concentration of 50 to 100 mass percent of the total solids.

[0022]

[11] . The photosensitive composition according to any one of [8] to

[10] , which reacts with actinic radiation having a wavelength of 6 nm or more and 15 nm or less.

[0023]

[12] . A pattern forming method comprising a step of applying the photosensitive composition according to

[11] onto a substrate, a step of exposing to actinic radiation, and a step of developing using a developer.

[0024]

[13] The pattern formation method according to

[12] , wherein the developing solution is an organic solvent having a solubility parameter (SP value) of 7.5 or more and 11 or less.

[0025] A substrate having a pattern layer obtained by the pattern formation method described in

[14] ,

[12] , or

[13] .

[0026] A method for manufacturing a substrate in which a pattern layer is formed by the pattern forming method described in

[15] ,

[12] , or

[13] .

[0027]

[16] A transition metal cluster compound containing a transition metal atom and a carboxyl ligand represented by the following chemical formula (2).

[0028] TIFF2026170520000002.tif46170

[0029] In the above chemical formula (2), n is 4, and X, Y, and Z constitute a heterocycle and are each independently one of the atoms selected from C (carbon), N (nitrogen), S (sulfur), O (oxygen), Si (silicon), Ge (germanium), P (phosphorus), Se (selenium), and Te (tellurium). If there are multiple Zs, the Zs may be different atoms and may form double bonds between them. m is an integer from 0 to 6, and R is each independently an organic group or a halogen. [Effects of the Invention]

[0030] The transition metal cluster compound of the present invention can enable miniaturization of circuit patterns. Because it has a ring-closed structure, the ligand size is small, the volume occupied by the ligand is small, and because the ligand is composed of atoms such as carbon and oxygen, the volume is small. Furthermore, the mass proportion of metal atoms contained in the compound is large, resulting in a high material density. Therefore, it is considered that when coated on a silicon wafer, the density of the resist film is high, the roughness generated on the side walls of the pattern when the pattern is exposed is small, and a high-resolution pattern is produced. Detailed description of the invention

[0031] The present invention will be described below based on one embodiment. However, the present invention is not limited to this embodiment. In this specification, there are instances where "~" is used to indicate a numerical range from a lower limit to an upper limit. In these instances, the numerical range refers to a range of values ​​that are greater than or equal to the lower limit and less than or equal to the upper limit, including the lower limit itself and the upper limit itself. Furthermore, in this invention, an organic group refers to a group having carbon, that is, a functional group such as a carboxyl group or an aldehyde group, or a hydrocarbon group such as a methyl group or an ethyl group, and a halogen refers to a fluorine atom, a chlorine atom, a bromine atom, etc.

[0032] [Transition metal cluster compounds] The transition metal cluster compound of one embodiment of the present invention is a compound that forms a cluster centered on a transition metal atom, and is a transition metal cluster compound that contains a transition metal atom and a carboxyl ligand represented by the following chemical formula (1).

[0033] TIFF2026170520000003.tif46170

[0034] In the above chemical formula (1), n ​​is an integer from 1 to 3 or from 5 to 6, and X, Y, and Z are each independently selected from C (carbon), N (nitrogen), S (sulfur), O (oxygen), Si (silicon), Ge (germanium), P (phosphorus), Se (selenium), and Te (tellurium). If there are multiple Zs, the Zs may be different atoms and may form double bonds with each other. m is an integer from 0 to 8, and R is each independently an organic group or a halogen.

[0035] Furthermore, the transition metal cluster compounds of other embodiments of the present invention are compounds that form a cluster centered on a transition metal atom, and are transition metal cluster compounds that contain a transition metal atom and a carboxyl ligand represented by the following chemical formula (2).

[0036] TIFF2026170520000004.tif46170

[0037] In the above chemical formula (2), n is 4, and X, Y, and Z constitute a heterocycle and are each independently one of the atoms selected from C (carbon), N (nitrogen), S (sulfur), O (oxygen), Si (silicon), Ge (germanium), P (phosphorus), Se (selenium), and Te (tellurium). If there are multiple Zs, the Zs may be different atoms and may form double bonds between them. m is an integer from 0 to 6, and R is each independently an organic group or a halogen.

[0038] In the present invention, a cluster compound refers to a metal complex molecule having metal atoms and ligands, in which multiple metal atoms are bonded to each other directly or through bridging ligands, and includes compounds having multiple metal atoms, in which the metal atoms have metal-metal bonds with each other, or are bonded with 1 to 3 atoms separating them. Furthermore, this cluster compound may contain oxygen and / or hydroxyl groups within its structure, and preferably may contain a μ-oxo ligand (μ-O) and / or a μ-hydroxyl group (μ-OH).

[0039] In the following, the transition metal cluster compound of the above-described embodiment and the transition metal cluster compound of the above-described other embodiment of the present invention will collectively be referred to as the cluster compound.

[0040] (transition metal atom) The transition metal atoms in this cluster compound are not particularly limited, but are preferably composed of 4 to 12 atoms, and more preferably consist of 4 to 6 atoms, as a smaller number is preferable from the viewpoint of suppressing pattern roughness when a lithography pattern is formed.

[0041] Furthermore, the transition metal atoms mentioned above include elements from groups 3 to 12 of the periodic table, specifically from the 4th period upwards. Among these, titanium, hafnium, and zirconium are preferred due to their ease of production by organic synthesis. Two or more transition metal atoms may be used in combination.

[0042] (carboxyl ligand) This cluster compound contains a carboxyl ligand represented by chemical formula (1) or chemical formula (2) above, and this carboxyl ligand has an unsaturated cyclic structure. In chemical formula (2), the cyclic structure constitutes a heterocycle.

[0043] In chemical formula (1), n ​​is an integer from 1 to 3 or from 5 to 6. From the viewpoint of suppressing pattern roughness when forming a lithography pattern, a smaller molecular size is preferable, so it is preferable to make n small. From the viewpoint of improving solubility in the coating solvent and developer and compound stability, it is preferable to make n large. Therefore, it is more preferable that n in chemical formula (1) be from 1 to 3, and particularly preferable that it be 3. In chemical formula (1), X, Y, and Z are each independently selected from C (carbon), N (nitrogen), S (sulfur), O (oxygen), Si (silicon), Ge (germanium), P (phosphorus), Se (selenium), and Te (tellurium), with C (carbon), N (nitrogen), S (sulfur), and O (oxygen) being preferred, X and Y being more preferably C (carbon) or N (nitrogen), Z being more preferably C (carbon), S (sulfur), or O (oxygen), and it is particularly preferred that all of X, Y, and Z are C (carbon).

[0044] In chemical formula (1), the cyclic structure preferably has one to two double bonds, and more preferably has one double bond. That is, the bonds between ZX, YZ, and Z-Z (when n=2 or more) may be double bonds, but it is preferable that they are all single bonds.

[0045] In chemical formula (1), m is an integer between 0 and 8, and it is preferable to change the integer value of m to adjust the solubility in the coating solvent and developer. Generally, sufficient solubility can often be obtained even when m is 0, but if not, the solubility problem is often solved when m is 2. Therefore, m is often between 0 and 2. Furthermore, in chemical formula (1), R is independently an organic group or a halogen, and as an organic group, a group having 1 to 15 carbon atoms is preferred, a group having 1 to 10 carbon atoms is more preferred, and a group having 1 to 5 carbon atoms is particularly preferred. In addition, the organic group may also contain heteroatoms. Preferred organic groups include hydrocarbon groups such as alkyl groups, alkenyl groups, and aromatic groups, and these hydrocarbon groups may be substituted with one or more functional groups or halogen atoms. Examples of functional groups include hydroxyl groups, aldehyde groups, carboxyl groups, nitro groups, amide groups, sulfo groups, alkoxy groups, and ketone groups. Furthermore, the hydrocarbon groups may contain heteroatoms, such as oxygen, nitrogen, phosphorus, sulfur, silicon, chlorine, bromine, and iodine. Examples of hydrocarbon groups include saturated hydrocarbon groups such as methyl, ethyl, n-propyl, and isopropyl groups; unsaturated hydrocarbon groups such as vinyl and isopropenyl groups; aryl groups such as phenyl and biphenyl groups; arylalkyl groups such as benzyl groups; and halogenated alkyl groups such as trifluoromethyl, monobromomethyl, and monoiodomethyl groups. Furthermore, when the organic group contains a heteroatom, it may be an organic group having an alkoxy group, hydroxyl group, amino group, etc. Examples include alkoxyalkyl groups such as alkoxymethyl group, alkoxyethyl group, and alkoxypropyl group; hydroxyalkyl groups such as hydroxymethyl group, hydroxyethyl group, and hydroxypropyl group; aminoalkyl groups such as aminomethyl group, aminoethyl group, and aminopropyl group; and halogenated alkyl groups such as halogenated methyl group, halogenated ethyl group, and halogenated propyl group. When the organic group contains a halogen, examples include fluorine, chlorine, and bromine. From the viewpoint of solubility and molecular size, methyl, ethyl, and n-propyl groups are preferred. However, methyl groups are preferred because they are easier to handle in terms of controlling solubility.

[0046] In chemical formula (2), X, Y, and Z are each independently selected from C (carbon), N (nitrogen), S (sulfur), O (oxygen), Si (silicon), Ge (germanium), P (phosphorus), Se (selenium), and Te (tellurium), with C (carbon), N (nitrogen), S (sulfur), and O (oxygen) being preferred, and X and Y being more preferably C (carbon) or N (nitrogen), and Z being more preferably C (carbon), S (sulfur), or O (oxygen). Note that in chemical formula (2), none of X, Y, and Z can be C (carbon).

[0047] In chemical formula (2), the cyclic structure preferably has one to two double bonds, and more preferably one double bond. That is, the bonds between ZX, YZ, and Z-Z (when n=2 or more) may be double bonds, but it is preferable that they are all single bonds. Having one double bond stabilizes the radical species generated after exposure, which often improves exposure sensitivity.

[0048] In chemical formula (2), m is an integer from 0 to 6, and it is preferable to change the integer value of m to adjust the solubility in the coating solvent and developer. Generally, sufficient solubility can often be obtained even when m is 0, but if not, the solubility can be adjusted by increasing the value of m. Furthermore, in chemical formula (2), R is independently either an organic group or a halogen, and examples of organic groups and halogens include those shown in chemical formula (1) above.

[0049] To give a more specific example of chemical formula (1), see formulas A1 to A23 below.

[0050] TIFF2026170520000005.tif43170

[0051] TIFF2026170520000006.tif47170

[0052] TIFF2026170520000007.tif46170

[0053] TIFF2026170520000008.tif45170

[0054] TIFF2026170520000009.tif55170

[0055] TIFF2026170520000010.tif46170

[0056] TIFF2026170520000011.tif52170

[0057] TIFF2026170520000012.tif52170

[0058] TIFF2026170520000013.tif52170

[0059] TIFF2026170520000014.tif54170

[0060] TIFF2026170520000015.tif44170

[0061] TIFF2026170520000016.tif45170

[0062] TIFF2026170520000017.tif41170

[0063] TIFF2026170520000018.tif44170

[0064] TIFF2026170520000019.tif44170

[0065] TIFF2026170520000020.tif45170

[0066] TIFF2026170520000021.tif36170

[0067] TIFF2026170520000022.tif42170

[0068] TIFF2026170520000023.tif41170

[0069] TIFF2026170520000024.tif40170

[0070] TIFF2026170520000025.tif37170

[0071] TIFF2026170520000026.tif37170

[0072] TIFF2026170520000027.tif36170

[0073] Among the above formulas A1 to A23, formula A3 or A4 is preferred in terms of compound stability, solubility in coating solvents and developers, ease of production, and the size of the compound that suppresses pattern roughness. In other words, cyclopentenecarboxylic acid, which may have substituents such as organic groups or halogens, is preferred.

[0074] To give a more specific example of chemical formula (2), consider the following equations B1 to B2.

[0075] TIFF2026170520000028.tif42170

[0076] TIFF2026170520000029.tif37170

[0077] Of the above formulas B1 to B2, formula B1 is preferred from the viewpoint of ease of synthesis.

[0078] In the above formulas A1 to A23 and B1 to B2, R, R1 ~R 18 , R 35 ~R 122 and R 129 ~R 177 R in chemical formula (1) or (2) represents the R in the formula, and as described above, each independently represents an organic group or a halogen.

[0079] [Manufacturing method] This cluster compound can be produced, for example, by reacting a compound containing a transition metal atom with a carboxylic acid having a carboxyl ligand structure in solution. As an example, it can be produced by reacting a solution containing a compound containing a transition metal atom with a carboxylic acid having a carboxyl ligand structure.

[0080] Examples of compounds containing transition metal atoms include organic compounds containing transition metal atoms such as metal alkoxides, specifically zirconium-n-propoxide, zirconium tertiary butoxide, hafnium-n-propoxide, and hafnium tertiary butoxide.

[0081] Examples of carboxylic acids having a carboxyl ligand structure include carboxylic acids in which a carboxyl group is bonded to a cyclic structure having at least one double bond, such as cycloalkenes and heterocycles.

[0082] More specifically, carboxylic acids having a carboxyl ligand structure include structures in which a hydrogen atom cation is bonded to an oxygen atom anion in chemical formulas A1-A23 and B1-B2.

[0083] To describe the manufacturing method in more detail, it can be carried out by placing a solution containing a compound with a transition metal atom and a carboxylic acid having a carboxyl ligand structure into a reaction vessel and stirring. A solvent may be added to dissolve the raw materials.

[0084] The reaction temperature is preferably between room temperature and 150°C, more preferably between room temperature and 120°C, from the viewpoint of completing the reaction and avoiding undesirable side reactions. The reaction time is preferably between 1 and 100 hours, more preferably between 1 and 24 hours.

[0085] If the product precipitates or crystallizes after the reaction, the compound can be obtained by filtering. Alternatively, the reaction solution may be cooled to -30°C to 20°C to induce precipitation or crystallization of the product. If no product precipitate is observed after the reaction, the target product can be recovered by removing the solvent by reducing the pressure of the reaction vessel. Alternatively, the product can be reprecipitated by bringing the reaction solution into contact with a poor solvent.

[0086] A sealed container is preferable as the reaction vessel; for small quantities, a Schlenk tube, for example, can be used, and the reaction is preferably carried out under a nitrogen or argon atmosphere. The reaction vessel should preferably be a flask equipped with a reflux tubing, and when heating, it is preferable to carry out the reaction under a nitrogen or argon atmosphere.

[0087] A solution containing a compound with a transition metal atom and a carboxylic acid having a carboxyl ligand structure are preferably blended in a molar ratio of 1:2 to 1:4, and more preferably in a ratio of 1:4.

[0088] [Photosensitive composition] A photosensitive composition according to one embodiment of the present invention (hereinafter also referred to as "the photosensitive composition") contains the cluster compound. The photosensitive composition may contain only one of the cluster compounds, or it may contain two or more. The content of the cluster compound in the photosensitive composition is at a concentration of 50% by mass or more and 100% by mass or less of the total solids of the photosensitive composition, preferably at a concentration of 60% by mass or more and 100% by mass or less, and particularly preferably at a concentration of 70% by mass or more and 90% by mass or less. If the content of the cluster compound in this photosensitive composition is above the lower limit mentioned above, good exposure sensitivity can be obtained.

[0089] [Photoacid Generator] This photosensitive composition can also function by including a photoacid generator that produces acid upon the action of chemical radiation, along with the cluster compound. Examples of chemical radiation include the emission spectrum of mercury lamps, far ultraviolet light represented by excimer lasers, extreme ultraviolet (EUV) light, X-rays, and electron beams. However, from the viewpoint of resolution, a smaller exposure wavelength is preferable, and preferably, extreme ultraviolet (EUV) light emitting light with a wavelength of 6 nm or more and 15 nm or less is preferred.

[0090] While there are no particular limitations on the photoacid generators that generate acids by chemical radiation, known compounds are preferred, as they generate at least one of organic acids, such as sulfonic acid, bis(alkylsulfonyl)imide, and tris(alkylsulfonyl)methide, upon irradiation with chemical radiation.

[0091] The photoacid generator can be used alone or in combination of two or more types. When using two or more types in combination, for example, (1) using two photoacid generators with different acid strengths, or (2) using two photoacid generators with different sizes (molecular weight or number of carbon atoms) of generated acids, are preferred.

[0092] Examples of the embodiment of (1) include the combined use of a fluorine-containing sulfonic acid generator and a tris(fluoroalkylsulfonyl)methidic acid generator, the combined use of a fluorine-containing sulfonic acid generator and a fluorine-free sulfonic acid generator, and the combined use of an alkyl sulfonic acid generator and an aryl sulfonic acid generator.

[0093] (2) An example of the embodiment is the combined use of two different acid generators, the generated acid anions having four or more carbon atoms.

[0094] In particular, the photosensitive composition is preferably a photosensitive composition used in response to chemical radiation. A photosensitive composition that reacts to chemical radiation is preferable because it changes the development rate in the developer solution, allowing a pattern to be formed after a certain period of development.

[0095] As for chemical radiation, a smaller wavelength is preferable because it provides higher resolution, and preferably chemical radiation with a wavelength of 6 nm or more and 15 nm or less, more preferably with a wavelength of 6.5 nm or less and 13.5 nm or less. In other words, extreme ultraviolet (EUV) light is preferred. In other words, it is preferable that the photosensitive composition is a photosensitive composition that reacts to chemical radiation with a wavelength of 6 nm or more and 15 nm or less.

[0096] This photosensitive composition reacts to light even when used alone. When a photoacid generator is added, it reacts synergistically with the compound in the photosensitive composition, thereby enhancing the photosensitivity of the compound. Therefore, if a photosensitive composition composed solely of this cluster compound has insufficient photosensitivity to the required specifications, it is preferable to add a photoacid generator.

[0097] If the photosensitive composition contains a photoacid generator, the amount of photoacid generator in the photosensitive composition (total amount if multiple are used in combination) is preferably 0.1 to 30% by mass, more preferably 0.5 to 20% by mass, and even more preferably 1 to 15% by mass, based on the total amount of components other than the solvent in the photosensitive composition.

[0098] If the content of the photoacid generator in the photosensitive composition is above the lower limit, an effect of enhancing photosensitivity can be obtained. If it is below the upper limit, it is less affected by the poor film-forming properties of the photoacid generator, and therefore good film-forming properties based on this photosensitive compound can be obtained, which is preferable.

[0099] [solvent] This photosensitive composition typically contains a solvent for preparation. The solvent used to prepare the photosensitive composition is not particularly limited as long as it dissolves each component, but examples include toluene, alkylene glycol monoalkyl ether carboxylate (such as propylene glycol monomethyl ether acetate (PGMEA; 1-methoxy-2-acetoxypropane)), alkylene glycol monoalkyl ether (such as propylene glycol monomethyl ether (PGME; 1-methoxy-2-propanol)), alkyl lactate ester (such as ethyl lactate, methyl lactate), cyclic lactone (such as γ-butyrolactone, preferably with 4 to 10 carbon atoms), linear or cyclic ketone (such as 2-heptanone, cyclohexanone, preferably with 4 to 10 carbon atoms), alkylene carbonate (such as ethylene carbonate, propylene carbonate), alkyl carboxylate (alkyl acetate such as butyl acetate is preferred), alkyl alkoxy acetate (ethyl ethoxypropionate), alkylamide (N,N-dimethylformamide), alkyl sulfoxide (dimethyl sulfoxide), and the like. Other usable solvents include, for example, those described in paragraphs

[0244] and onward of U.S. Patent Application Publication No. 2008 / 0248425A1.

[0100] Of the above, toluene, PGMEA, ethyl lactate, cyclohexanone, 2-heptanone, N,N-dimethylformamide, dimethyl sulfoxide, alkylene glycol monoalkyl ether carboxylate, and alkylene glycol monoalkyl ether are preferred. These solvents may be used individually or in mixtures of two or more. When mixing two or more, it is preferable to mix a solvent having hydroxyl groups with a solvent that does not have hydroxyl groups.

[0101] As a solvent having a hydroxyl group, alkylene glycol monoalkyl ether is preferred, and as a solvent without a hydroxyl group, alkylene glycol monoalkyl ether carboxylate, N,N-dimethylformamide, and dimethyl sulfoxide are preferred.

[0102] The solvent for this photosensitive composition is preferably a solvent with a solubility parameter (SP value) of 7.5 to 11, and more preferably 8 to 11. The solubility parameter (SP value) will be described later. The solvent content in the total amount of this photosensitive composition can be adjusted as appropriate depending on the pattern thickness to be formed, but generally, the total concentration of components other than the solvent in the photosensitive composition is adjusted to be 0.5 to 30% by mass, preferably 1.0 to 20% by mass, more preferably 1.5 to 10% by mass, and particularly preferably 1.5 to 5% by mass.

[0103] [Surfactants] The photosensitive composition preferably further contains a surfactant. Fluorine-based and / or silicone-based surfactants are preferred. Examples of surfactants that fall into this category include Megafac F176 and Megafac R08 from Dainippon Ink and Chemicals, Inc., PF656 and PF6320 from OMNOVA, Inc., Troisol S-366 from Troy Chemical Co., Ltd., Florad FC430 from Sumitomo 3M Co., Ltd., and Polysiloxane Polymer KP-341 from Shin-Etsu Chemical Co., Ltd.

[0104] In addition, other surfactants besides fluorine-based and / or silicone-based surfactants can be used. More specifically, examples include polyoxyethylene alkyl ethers and polyoxyethylene alkylaryl ethers. Other known surfactants can be used as appropriate. Examples of usable surfactants include those described in paragraph

[0273] and subsequent paragraphs of U.S. Patent Application Publication No. 2008 / 0248425A1. Surfactants may be used alone or in combination of two or more types. The surfactant content is preferably 0.0001 to 2% by mass, more preferably 0.001 to 1% by mass, relative to the total amount of components other than the solvent in the photosensitive composition.

[0105] [resin] This photosensitive composition can form patterns on its own, but it may also contain resin materials in addition to the cluster compound. The resin material is not particularly limited as long as it is soluble in the solvent, but examples include novolac resins, styrene resins, and acrylic resins. These resins may also contain one or more copolymers.

[0106] Furthermore, these resins may be used individually or in mixtures of two or more, and their molecular structure may contain dissolution-inhibiting groups that decompose by chemically active species such as acids and radicals, and crosslinking groups that crosslink. Examples of dissolution-inhibiting groups that decompose by chemically active species such as acids and radicals include alkoxycarbonyl groups and acetal groups. Examples of crosslinking groups that crosslink by chemically active species such as acids and radicals include vinyl groups, carbodiimide groups, N-hydroxyester groups, imide ester groups, maleimide groups, haloacetyl groups, pyridyl disulfide groups, hydrazide groups, alkoxyamino groups, and diazirine groups.

[0107] [Other additives] In addition to the components described above, this photosensitive composition may appropriately contain carboxylic acids, onium carboxylic acid salts, dissolution inhibitors with a molecular weight of 3000 or less as described in Proceedings of SPIE, 2724, 355 (1996), dyes, plasticizers, photosensitizers, light absorbers, crosslinking agents, antioxidants, and the like. Carboxylic acids, in particular, are preferably used to improve performance. Aromatic carboxylic acids, such as benzoic acid and naphthoic acid, are preferred. The carboxylic acid content is preferably 0.01 to 10% by mass, more preferably 0.01 to 5% by mass, and even more preferably 0.01 to 3% by mass, relative to the total amount of components other than the solvent in the photosensitive composition.

[0108] [Method for producing this photosensitive composition] This photosensitive composition can be prepared by dissolving the cluster compound, a photoacid generator and other components as needed in a solvent for preparation, and filtering the mixture as necessary. The filter is preferably made of polytetrafluoroethylene, polyethylene, or nylon with a pore size of 0.2 μm or less, more preferably 0.1 μm or less, and even more preferably 0.05 μm or less.

[0109] [Pattern formation method] A pattern formation method according to one embodiment of the present invention (hereinafter also referred to as the "pattern formation method") includes the steps of: applying the photosensitive composition to a substrate; exposing it with chemical radiation; and developing it. More specifically, the process includes the steps of: applying the photosensitive composition onto a substrate to form a photosensitive layer; irradiating a predetermined area of ​​the photosensitive layer with chemical radiation to perform pattern exposure; and developing the photosensitive layer after exposure with a developer to selectively remove the exposed or unexposed areas of the photosensitive layer.

[0110] [Photosensitive layer formation process] The photosensitive layer can be formed by applying the photosensitive composition onto a substrate (e.g., silicon, silicon dioxide coated) used in the manufacture of integrated circuit elements using a suitable coating method such as a spinner, and then drying it at 50 to 150°C. In this case, commercially available inorganic or organic anti-reflective coatings can be used as needed. Furthermore, an anti-reflective coating can also be applied to the layer beneath the resist.

[0111] [Synthesis process] In this invention, unless otherwise specified, "exposure with chemical radiation" includes not only exposure with far ultraviolet light such as mercury lamps and excimer lasers, X-rays, and extreme ultraviolet (EUV) light, but also drawing with particle beams such as electron beams and ion beams. Exposure can be performed by pattern exposure, which involves irradiating a predetermined area of ​​the formed photosensitive layer with chemical radiation through a predetermined mask, or by pattern exposure by direct drawing (direct drawing) without using a mask, using an electron beam. The chemical radiation is not particularly limited, but examples include KrF excimer lasers, ArF excimer lasers, extreme ultraviolet (EUV) light, and electron beams. Extreme ultraviolet (EUV) light and electron beams are preferred, and as mentioned above, extreme ultraviolet (EUV) light that emits chemical radiation with a wavelength of 6 nm to 15 nm is preferred.

[0112] After the exposure described above, you may or may not bake (heat) the film before developing it. When baking (heating), the heating temperature is preferably 50 to 200°C, more preferably 60 to 180°C, and even more preferably 80 to 150°C. When baking (heating), the heating time is preferably 30 to 300 seconds, more preferably 30 to 180 seconds, and even more preferably 30 to 90 seconds. Heating can be performed using the methods available in a standard exposure and developing machine, or it may be done using a hot plate or similar device.

[0113] [Development process] After exposure, development is performed to selectively remove the exposed or unexposed areas of the photosensitive layer. The development method can be any known technique, such as a gas-based method or a developer-based method.

[0114] <Developer> As the developer, an organic solvent is preferably used, and an organic solvent with a vapor pressure of 5 kPa or less at 20°C is preferred, more preferably 3 kPa or less, and particularly preferred 2 kPa or less. By reducing the vapor pressure of the organic solvent to 5 kPa or less, evaporation of the developer on the substrate or in the developing cup is suppressed, improving temperature uniformity within the pattern-forming substrate surface, and consequently improving dimensional uniformity within the pattern-forming substrate surface.

[0115] Various organic solvents can be used as the developing solution. For example, at least one solvent selected from ester solvents, ketone solvents, alcohol solvents, amide solvents, sulfoxide solvents, ether solvents, hydrocarbon solvents, etc., can be used.

[0116] Examples of ester solvents include alkyl carboxylate solvents such as methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, ethyl-3-ethoxypropionate, propylene glycol diacetate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, and propyl lactate; alkylene glycol monoalkyl ether carboxylate solvents such as propylene glycol monomethyl ether acetate (PGMEA; also known as 1-methoxy-2-acetoxypropane), ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, and propylene glycol monoethyl ether acetate; butyl acetate, amyl acetate, ethyl lactate, and propylene glycol monomethyl ether acetate are more preferred.

[0117] Examples of ketone solvents include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, phenylacetone, methyl ethyl ketone, methyl amyl ketone, methyl isobutyl ketone, acetylacetone, acetonylacetone, ionone, diacetonyl alcohol, acetylcarbinol, acetophenone, methyl naphthyl ketone, isophorone, propylene carbonate, etc. Alkyl ketone solvents, such as methyl isobutyl ketone, methyl amyl ketone, cyclopentanone, cyclohexanone, and 2-heptanone, are more preferred.

[0118] Examples of alcohol-based solvents include methyl alcohol, ethyl alcohol, n-propyl alcohol containing 1-propanol or 2-propanol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, hexyl alcohol such as n-hexyl alcohol, heptyl alcohol such as n-heptyl alcohol, octyl alcohol such as n-octyl alcohol, n-decanol, and glycols such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, and 1,4-butylene glycol. Examples of suitable solvents include alkylene glycol monoalkyl ether solvents such as ethylene glycol monomethyl ether, propylene glycol monomethyl ether (PGME; also known as 1-methoxy-2-propanol), ethylene glycol monoethyl ether, propylene glycol monoethyl ether, diethylene glycol monomethyl ether, and triethylene glycol monoethyl ether; glycol ether solvents such as methoxymethyl butanol and propylene glycol dimethyl ether; and phenolic solvents such as phenol and cresol. 1-hexanol, 2-hexanol, 1-octanol, 2-ethyl-hexanol, propylene glycol monomethyl ether, and cresol are more preferred. Examples of amide solvents that can be used include N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, hexamethylphosphoric triamide, and 1,3-dimethyl-2-imidazolidinone.

[0119] Examples of sulfoxide solvents that can be used include dimethyl sulfoxide.

[0120] Examples of ether-based solvents include the alkylene glycol monoalkyl ether solvents and glycol ether solvents mentioned above, as well as dioxane, tetrahydrofuran, tetrahydropyran, and the like.

[0121] Examples of hydrocarbon solvents include aromatic hydrocarbon solvents such as toluene and xylene, and aliphatic hydrocarbon solvents such as pentane, hexane, octane, decane, and dodecane.

[0122] The developer preferably contains one or more solvents selected from alkylene glycol monoalkyl ether carboxylate solvents, alkylene glycol monoalkyl ether solvents, alkyl carboxylate solvents, and alkyl ketone solvents, and more preferably contains one or more solvents selected from dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, ethylene glycol, methyl alcohol, ethyl alcohol, 1-propanol, and 2-propanol.

[0123] It is preferable to use a developer that contains at least one organic solvent selected from the group consisting of ester solvents that do not have hydroxyl groups in their molecules, ketone solvents that do not have hydroxyl groups in their molecules, and ether solvents, amide solvents, and sulfoxide solvents that do not have hydroxyl groups in their molecules.

[0124] In this invention, the organic solvent used as the developer is preferably an organic solvent with a solubility parameter (SP value) of 7.5 or higher and 11 or lower. An organic solvent with a solubility parameter of 7.5 or higher is preferable because it increases the development speed in the dissolution area, and an organic solvent with a solubility parameter of 11 or lower is preferable because it suppresses the development speed in the pattern formation area. More preferably, the solubility parameter of the organic solvent in the developer is between 8 and 11.

[0125] In this invention, the solubility parameter (SP value) is calculated using the method proposed by Fedors et al. Specifically, the value is obtained by referring to "POLYMER ENGINEERING AND SCIENCE, FEBRUARY, 1974, Vol.14, No.2, ROBERT F. FEDORS. (P.147-154)". Furthermore, the SP value is a physical property determined by the content of hydrophobic and hydrophilic groups in the molecule, and when a mixed solvent is used, it represents the value for the mixture.

[0126] Organic solvents that satisfy the above SP values ​​include diethylene glycol monomethyl ether (SP value = 10.7), triethylene glycol monomethyl ether (SP value = 10.7), ethylene glycol monoisopropyl ether (SP value = 10.9), ethylene glycol monobutyl ether (SP value = 10.2), diethylene glycol monobutyl ether (SP value = 10.0), triethylene glycol monobutyl ether (SP value = 10.0), ethylene glycol monoisobutyl ether (SP value = 9.1), ethylene glycol monohexyl ether (SP value = 9.9), diethylene glycol monohexyl ether (SP value = 9.7), diethylene glycol mono-2-ethylhexyl ether (SP value = 9.3), ethylene glycol monoallyl ether (SP value = 10.8), ethylene glycol monophenyl ether (SP value = 10.8), ethylene glycol monobenzyl ether (SP value = 10.9), propylene glycol monomethyl ether (SP value = 10.0), and dipropylene glycol Polypropylene glycol monomethyl ether (SP value = 9.7), tripropylene glycol monomethyl ether (SP value = 9.4), propylene glycol monopropyl ether (SP value = 9.6), dipropylene glycol monopropyl ether (SP value = 9.8), propylene glycol monobutyl ether (SP value = 9.0), dipropylene glycol monobutyl ether (SP value = 9.6), ethylene glycol monomethyl ether acetate (SP value = 10.0), ethylene glycol monoethyl ether acetate Examples include tate (SP value = 9.6), ethylene glycol monobutyl ether acetate (SP value = 8.9), diethylene glycol monoethyl ether acetate (SP value = 9.4), diethylene glycol monobutyl ether acetate (SP value = 9.0), propylene glycol monomethyl ether acetate (SP value = 9.4), propylene glycol monoethyl ether acetate (SP value = 9.0), or dipropylene glycol monomethyl ether acetate (SP value = 9.2). The above organic solvents may be used in combination, or they may be used in combination with other solvents or water.

[0127] The concentration of the above-mentioned organic solvent (total in the case of a mixture of multiple solvents) in the developing solution is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more. Particularly preferable is when it consists substantially only of organic solvents. The term "consisting substantially only of organic solvents" includes cases where trace amounts of surfactants, antioxidants, stabilizers, defoamers, etc., are included.

[0128] The water content in the developing solution is preferably 10% by mass or less, more preferably 5% by mass or less, particularly preferably 3% by mass or less, and most preferably substantially water-free. By reducing the water content to 10% by mass or less, good developing characteristics can be obtained.

[0129] A suitable amount of surfactant may be added to the developing solution used in this invention as needed. As the surfactant, the same surfactant as described above for use in the photosensitive composition of the present invention can be used. The amount of surfactant used is typically 0.001 to 5% by mass, preferably 0.005 to 2% by mass, and more preferably 0.01 to 0.5% by mass, relative to the total amount of the developing solution.

[0130] <Developing method> For example, development methods such as immersing the substrate in a tank filled with developer for a certain period of time (dip method), developing by puddling the developer onto the substrate surface using surface tension and leaving it still for a certain period of time (paddle method), spraying the developer onto the substrate surface (spray method), and continuously dispensing the developer onto a substrate rotating at a constant speed while scanning the developer dispensing nozzle at a constant speed (dynamic dispensing method) can be applied.

[0131] Alternatively, after the development process, a step may be performed to stop the development process while replacing the solvent with another solvent. The development time is preferably long enough for the cluster compound and other components in the photosensitive layer of the unexposed or exposed areas to dissolve sufficiently, and is usually 10 to 300 seconds, more preferably 20 to 120 seconds. The temperature of the developer is preferably 0 to 50°C, and more preferably 15 to 35°C. The amount of developer can be adjusted as needed depending on the development method.

[0132] [Rinsing process] This pattern formation method may include a step of washing with a rinsing solution containing an organic solvent after the development step.

[0133] <Rinsing solution> The organic solvent used in the rinsing solution preferably has a vapor pressure of 0.05 kPa or more and 5 kPa or less at 20°C, more preferably 0.1 kPa or more and 5 kPa or less, and most preferably 0.12 kPa or more and 3 kPa or less. By setting the vapor pressure of the organic solvent used in the rinsing solution to 0.05 kPa or more and 5 kPa or less, the temperature uniformity within the wafer surface is improved, and swelling caused by the penetration of the rinsing solution is suppressed, thereby improving the dimensional uniformity within the wafer surface.

[0134] Various organic solvents can be used as the rinsing solution, but for this compound, it is preferable to use a rinsing solution containing at least one organic solvent selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents, or water. More preferably, after development, a washing step is performed using a rinsing solution containing at least one organic solvent selected from ketone solvents, ester solvents, alcohol solvents, amide solvents, and hydrocarbon solvents. Even more preferably, after development, a washing step is performed using a rinsing solution containing at least one organic solvent selected from the group consisting of alcohol solvents and hydrocarbon solvents.

[0135] Specific examples of ketone solvents, ester solvents, alcohol solvents, amide solvents, ether solvents, and hydrocarbon solvents used as rinsing solutions are the same as those described above for developing solutions. Particularly preferred is a rinse solution containing at least one organic solvent selected from the group consisting of monohydric alcohol solvents, hydrocarbon solvents, and amide solvents.

[0136] Here, monohydric alcohol-based solvents used in the rinsing step after development include linear, branched, and cyclic monohydric alcohols. Specifically, 1-butanol, 2-butanol, 3-methyl-1-butanol, tert-butyl alcohol, isopropyl alcohol, cyclopentanol, cyclohexanol, etc., are used, with 1-butanol, 2-butanol, 3-methyl-1-butanol, and isopropyl alcohol being preferred.

[0137] Examples of hydrocarbon solvents include aromatic hydrocarbon solvents such as toluene and xylene, and aliphatic hydrocarbon solvents such as octane, decane, and dodecane. As an amide solvent, N,N-dimethylformamide can be used. The aforementioned components may be mixed in multiple quantities, or they may be mixed with organic solvents other than those mentioned above and used together.

[0138] The above organic solvent may be mixed with water, but the water content in the rinsing solution is usually 30% by mass or less, preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 3% by mass or less. It is most preferable that the rinsing solution does not contain water. Good developing characteristics can be obtained by keeping the water content at 30% by mass or less.

[0139] The rinse solution can also be used with an appropriate amount of surfactant added. As the surfactant, the same surfactants used in photosensitive compositions as described above can be used, and the amount used is usually 0.001 to 5% by mass, preferably 0.005 to 2% by mass, and more preferably 0.01 to 0.5% by mass, relative to the total amount of the rinse solution.

[0140] <How to rinse> In the rinsing process, the developed pattern-forming substrate is washed using a rinsing solution containing the aforementioned organic solvent. The cleaning method is not particularly limited, but for example, a method of continuously applying rinsing solution onto a substrate rotating at a constant speed (rotary coating method), a method of immersing the substrate in a tank filled with rinsing solution for a certain period of time (dip method), or a method of spraying rinsing solution onto the surface of the substrate (spray method) can be applied. Among these, it is preferable to perform the cleaning process using the rotary coating method, and after cleaning, rotate the substrate at a rotation speed of 2000 to 4000 rpm to remove the rinsing solution from the substrate. The rotation time of the substrate can be set according to the rotation speed within a range that achieves removal of the rinsing solution from the substrate, but is usually from 10 seconds to 3 minutes. It is preferable to rinse under room temperature conditions.

[0141] The rinsing time is preferably such that no developing solvent remains on the substrate, and is usually 10 to 300 seconds. More preferably, it is 20 to 120 seconds. The temperature of the rinse solution is preferably 0 to 50°C, and more preferably 15 to 35°C. The amount of rinse solution can be adjusted as needed depending on the rinsing method.

[0142] [Post-processing steps] After the developing or rinsing process, the developer or rinse solution adhering to the pattern can be removed using a supercritical fluid. Furthermore, after development, rinsing, or treatment with a supercritical fluid, heat treatment can be performed to remove any remaining solvent in the pattern. The heating temperature and time are not particularly limited as long as a good resist pattern is obtained, and are usually 40-160°C and 10 seconds-3 minutes. The heat treatment may be performed multiple times.

[0143] [Use] The present photosensitive composition and the present pattern forming method are suitably used for fabrication of semiconductor fine circuits such as production of ultra-LSIs and high-capacity microchips, and can manufacture a substrate having a pattern layer. At the time of fabricating a semiconductor fine circuit, after the resist film on which a pattern is formed is subjected to circuit formation and etching, the remaining resist film portion is finally removed with a solvent or the like.

Examples

[0144] Hereinafter, an example of the present invention will be described. However, the present invention is not limited to this example. In addition, "parts" and "%" in the examples are based on mass unless otherwise specified.

[0145] The following Compound 1 was produced to obtain Example 1. The composition of each compound and the structure of the ligand are 1 measured by H-NMR.

[0146] <Compound 1> A reaction vessel was charged with 5 g (10.7 mmol) of a zirconium propoxide solution (70% propanol solution), 4.8 g (42.7 mmol) of 3-cyclopentenecarboxylic acid, and 5 g of toluene, the mixture was stirred at 100°C for 6 hours under nitrogen, and then the solvent was removed under reduced pressure to obtain 3.5 g of an amorphous solid. As a result of NMR analysis of the obtained solid, it was found that the solid had the structure described in the following Formula 1. 1 H-NMR (CDCl 3, ppm): 5.2-5.6 (br, 24H), 3.4-2.0 (br, 60H)

[0147] TIFF2026170520000030.tif50170

[0148] <Preparation of Photosensitive Composition (Resist Solution)> <Example 1> The above Compound 1 was dissolved in 2-heptanone at a concentration of 5% by mass, and filtered through a 0.2 μm filter to obtain a resist solution of Example 1.

[0149] <Formation and pattern drawing of resist films> The prepared resist solution was applied to a substrate (silicon wafer) with a pattern formed by spin coating to create a resist film with a thickness of approximately 40 nm. The resulting resist film was baked at 90°C for 90 seconds, and then patterned using an electron beam lithography system (electron beam acceleration voltage: 100 keV).

[0150] <Developing> After pattern drawing, the coating film of Example 1 was developed with 2-heptanone (25°C, 60 seconds) to obtain a negative-type pattern.

[0151] <Sensitivity measurement> Extreme ultraviolet (EUV) exposure was performed at varying exposure doses, and the film thickness of the resulting developed patterns was measured using a contact step meter. The EUV exposure dose at which the increase in film thickness was maximized was used as an indicator of sensitivity. Sensitivity is expressed as exposure dose (unit: mJ / cm²). 2 A lower exposure results in a higher value, while a higher exposure results in a lower value. The results are shown in Table 1 below.

[0152] <Comparative Example 1> Aldrich polystyrene (PS, mass-average molecular weight 4000) was dissolved in propylene glycol monomethyl ether acetate at a concentration of 2% by mass, and the solution was filtered through a 0.2 μm filter to obtain a resist solution. The resist solution of Comparative Example 1 was evaluated in the same manner as in Example 1, and the results are shown in Table 1 below.

[0153] [Table 1]

[0154] The results in Table 1 show that Example 1 had a smaller EUV irradiation dose when the change in film thickness was maximized compared to Comparative Example 1, and therefore demonstrated higher sensitivity.

[0155] <Resolution Evaluation> The resolution of Example 1 and Comparative Example 1 was evaluated using an electron beam lithography system. Resolution was evaluated by drawing line-and-space (line:space = 1:1) patterns with hp (half pitch) of 100 nm and 50 nm, developing them, and observing each pattern with a scanning electron microscope. "A" was assigned when the hp 100 nm or 50 nm line-and-space pattern could be confirmed, "B" when the pattern could be confirmed but partially crosslinked, and "C" when the pattern could not be confirmed. The results are shown in Table 2.

[0156] [Table 2]

[0157] [result] In Example 1, electron beam (EB) lithography tests showed that a half-pitch (hp) 100 nm line-and-space (L&S) pattern (1:1) could be formed, and a pattern with some crosslinking was also formed at 50 nm. Therefore, as shown in Table 1, it was confirmed that the material is highly sensitive to EUV exposure, and furthermore, as shown in Table 2, it also performs well in pattern writing at hp50nm, making the transition metal cluster compound of the present invention practical as a photoresist for ultrafine patterns.

Claims

1. A transition metal cluster compound containing a transition metal atom and a carboxyl ligand represented by the following chemical formula (1). (In the above chemical formula (1), n ​​is an integer from 1 to 3 or 5 to 6, and X, Y, and Z are each independently selected from C (carbon), N (nitrogen), S (sulfur), O (oxygen), Si (silicon), Ge (germanium), P (phosphorus), Se (selenium), and Te (tellurium). If there are multiple Zs, the Zs may be different atoms, and double bonds may be formed between the Zs. m is an integer from 0 to 8, and R is each independently an organic group or a halogen.)

2. The transition metal cluster compound according to claim 1, characterized in that X, Y, and Z in the above chemical formula (1) are all carbon, and the bonds between Z and X, Y and Z, and Z and Z (when n = 2 or more) are all single bonds.

3. The transition metal cluster compound according to claim 1, wherein n = 3 in the above chemical formula (1).

4. The transition metal cluster compound according to claim 3, characterized in that the carboxyl ligand is a cyclopentenecarboxylic acid which may have substituents.

5. The transition metal cluster compound according to claim 1, characterized by containing 4 to 12 of the aforementioned transition metal atoms.

6. The transition metal cluster compound according to claim 1, characterized in that the transition metal atom is one of titanium, hafnium, or zirconium.

7. A method for producing a transition metal cluster compound according to any one of claims 1 to 6, comprising reacting a compound containing the transition metal atom with a carboxylic acid having the structure of the carboxyl ligand in solution.

8. A photosensitive composition comprising a transition metal cluster compound according to any one of claims 1 to 6.

9. The photosensitive composition according to claim 8, further comprising a solvent.

10. A photosensitive composition characterized by containing a transition metal cluster compound according to any one of claims 1 to 6 at a concentration of 50 to 100 mass percent of the total solids.

11. The photosensitive composition according to claim 8, characterized in that it reacts with chemical radiation with a wavelength of 6 nm or more and 15 nm or less.

12. A method for forming a pattern, characterized by comprising the steps of: applying the photosensitive composition described in claim 11 to a substrate; exposing it with chemical radiation; and developing it using a developer.

13. The pattern forming method according to claim 12, wherein the developing solution is an organic solvent having a solubility parameter (SP value) of 7.5 or more and 11 or less.

14. A substrate having a pattern layer obtained by the pattern forming method described in claim 12.

15. A method for manufacturing a substrate in which a pattern layer is formed by the pattern forming method described in claim 12.

16. A transition metal cluster compound containing a transition metal atom and a carboxyl ligand represented by the following chemical formula (2). (In the above chemical formula (2), n is 4, and X, Y, and Z constitute a heterocycle and are each independently one of the atoms selected from C (carbon), N (nitrogen), S (sulfur), O (oxygen), Si (silicon), Ge (germanium), P (phosphorus), Se (selenium), and Te (tellurium). If there are multiple Zs, the Zs may be different atoms, and double bonds may be formed between the Zs. m is an integer from 0 to 6, and R is each independently an organic group or a halogen.)

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