Tin compound, resist solution comprising same, pattern forming method, thin film, patterned thin film, and method for producing tin compound

Abstract

To provide a tin compound as a high-performance resist material having high purity and uniform solubility.　A tin compound has a tin atom, an organic group R, and an oxo ligand and / or a hydroxo ligand. The diffraction angle 2θ (°) of the peak of the maximum intensity in the X-ray diffraction measurement is in 5.00-15.00°, the half-value width at the peak of the maximum intensity is 1.00-4.00°, and the organic group R has 1-30 carbon atoms.

Description

Tin compound, resist solution using the same, pattern forming method, thin film, patterned thin film, and method for producing tin compound

[0001] The present invention relates to a tin compound, a resist solution using the same, a pattern forming method, a thin film, a patterned thin film, and a method for producing the tin compound.

[0002] In recent years, against the backdrop of a paradigm shift toward an advanced information society, there is a demand for faster, larger amounts of information to be handled with greater precision, and semiconductor device technology, such as integrated circuits using semiconductors, is advancing remarkably every day.

[0003] Evolution in semiconductor design has necessitated the creation of ever-smaller features on semiconductor substrate materials, with individual features measuring approximately 22 nanometers (nm) or less, and in some cases, less than 10 nm. One challenge in the fabrication of devices with such fine features is the ability to reliably and reproducibly create photolithography masks with sufficient resolution. Achieving feature sizes smaller than the wavelength of light requires the use of complex high-resolution techniques, such as multiple patterning. Thus, the development of photolithography techniques using shorter wavelength light, such as extreme ultraviolet (EUV) light, which has wavelengths of 10 nm to 15 nm (e.g., 13.5 nm), is becoming increasingly important.

[0004] Conventional organic chemically amplified resists (CARs) have potential drawbacks when used in EUV lithography, particularly because they have low adsorption coefficients in the EUV region, which can lead to blurred diffusion of photoactivated species, large line width roughness (LWR), pattern collapse, etc. Therefore, there remains a need for improved EUV photoresist materials that have the properties of higher sensitivity, lower line width roughness (LWR), and better etch resistance.

[0005] For this reason, metal materials using organotin compounds and the like have recently begun to be used as resists, particularly for EUV applications. Specifically, for example, alkyltin oxo-hydroxo compounds synthesized by hydrolysis of high-purity monoalkyltin compounds have been reported as resist materials for EUV applications, and it has been reported that they can achieve very fine negative patterning with high resolution and low line width roughness (LWR). It has also been reported that branched alkyl groups, in particular, have excellent sensitivity (Patent Document 1).

[0006] It has also been reported that when a monoalkyltin compound containing a small amount of dialkyltin compounds as impurities is used as a resist material, it is excellent in reducing outgassing (Patent Document 2).

[0007] It has also been reported that alkyltin oxo-hydroxo compounds synthesized using hydrolyzable tin compounds having multiple alkyl groups as raw materials can achieve both high sensitivity and low line width roughness (LWR) (Patent Document 3).An example of synthesizing an alkyltin oxo-hydroxo compound by mixing an organometallic compound having a hydrolyzable group but no alkyl group has also been reported (Patent Document 4).

[0008] Japanese Patent Application Laid-Open No. 2021-21953 Japanese Patent Application Laid-Open No. 2021-519340 Japanese Patent Application Laid-Open No. 2019-500490 Japanese Patent Application Laid-Open No. 2023-27078

[0009] However, the alkyltin oxo-hydroxo compounds reported to date have been insufficient to achieve satisfactory performance as resist materials. In particular, the crystallinity of the tin composition, which affects solubility (in resist solvents and developer solvents) that is related to performance and quality as a resist raw material, has not been fully investigated. Specifically, it has not been clarified what ranges of the crystal structure and crystallinity of alkyltin oxo-hydroxo compounds are suitable for use in resist materials. Furthermore, no solutions have been proposed to achieve the two goals of controlling the crystal structure and crystallinity while synthesizing high-purity resist materials.

[0010] Under these circumstances, the present invention provides a tin compound as a high-performance resist material that is highly pure and has uniform solubility.

[0011] The present inventors conducted extensive research to solve the above problems and discovered that alkyltin oxo-hydroxo compounds (including compositions) having specific crystal structures and crystallinity provide excellent performance when used as resist materials. Furthermore, by using a composition (precursor) containing a monoalkyltin compound of a specific structure as a raw material and a combination of precursors of a specific composition, it is possible to achieve both the high purity required for resist materials and the ability to control the crystallinity to a desired level.

[0012] That is, the present invention has the following aspects: [1] A tin compound having a tin atom, an organic group R, and an oxo ligand and / or a hydroxo ligand, wherein the diffraction angle 2θ (°) of the peak with the maximum intensity in X-ray diffraction measurement is between 5.00 and 15.00°, the half-width of the maximum intensity peak is between 1.00 and 4.00°, and the organic group R has 1 to 30 carbon atoms. [2] The tin compound has a composition formula RSnO (3 / 2-X / 2) (OH) X [3] The tin compound according to [1], wherein the tin compound is represented by the chemical formula (RSn): 12 O 14 (OH)6 +2 [4] The tin compound according to [1], which is a compound containing a cation represented by the formula: 119 The sum (k1 + k2) of the peak integral value sum (k1) of five-coordinate Sn (-250 to -350 ppm) and the peak integral value sum (k2) of six-coordinate Sn (-450 to -600 ppm) in Sn-NMR, 119 The tin compound according to any one of [1] to [3], wherein the ratio [(k1 + k2) / (k3)] of the integral value of all peaks (including k1 and k2) in the range of 1000 to -1000 ppm detected by Sn-NMR to the total value (k3) is 0.9 or more. [5] 119The tin compound according to any one of [1] to [4], wherein the ratio (k1 / k2) of the total integrated value of the peaks of five-coordinated Sn (-250 to -350 ppm) in Sn-NMR to the total integrated value of the peaks of six-coordinated Sn (-450 to -600 ppm) is 0.5 to 2.5. [6] The tin compound according to any one of [1] to [5], wherein the half-width of the maximum intensity peak is 1.43 to 4.00°. [7] The tin compound according to any one of [1] to [6], wherein the organic group R has 3 to 10 carbon atoms. [8] The tin compound according to any one of [1] to [7], wherein the organic group R is a hydrocarbon group. [9] The organic group R is a hydrocarbon group, and 50 mol % or more of the substituents constituting the hydrocarbon group are secondary hydrocarbon groups R 2 The tin compound according to any one of [1] to [7], wherein the tin compound is a tin compound represented by formula (I).

[10] A resist solution comprising the tin compound according to any one of [1] to [9] and an organic solvent.

[11] A pattern formation method comprising the steps of applying the resist solution according to

[10] to a substrate, exposing the substrate to radiation, and developing the resist solution using a developer.

[12] A thin film on a substrate, comprising the tin compound according to any one of [1] to [9].

[13] A patterned thin film on a substrate, comprising the tin compound according to any one of [1] to [9].

[14] A method for manufacturing a substrate, comprising the pattern formation method according to

[11] .

[15] RSnX ２ A monoalkyltin compound represented by Y(B1). (In the general formula (B1), R is an organic group having 1 to 30 carbon atoms. X and Y are hydrolyzable groups having different chemical formulas, and X is one of OR', NR', 2、 C≡CR', and said Y is OR' Y , NR' Y 2、 C≡CR' Y The R' and R' are selected from the group consisting of Y is an organic group having 1 to 10 carbon atoms. Y In the case of 2, the R' and R' Y may be the same or different. YWhen there are a plurality of groups, they may have different structures, or may be bonded to each other to form a cyclic structure.

[16] The hydrolyzable groups X and Y are NR'2 and NR' Y 2, wherein the substituent NR'2 of X and the substituent NR' of Y Y

[17] The monoalkyltin compound according to

[15] , wherein X and Y are each a different chemical formula.

[17] The monoalkyltin compound according to

[15] , wherein X and Y are each a different chemical formula. Y wherein the substituent OR′ of X and the substituent OR′ of Y Y and Y are different chemical formulas.

[18] The monoalkyltin compound according to

[15] or

[16] , wherein the hydrolyzable group X is a substituent NR'2 and the hydrolyzable group Y is a substituent OR' Y

[19] The monoalkyltin compound according to any one of

[15] to

[17] , wherein the hydrolyzable group X is a substituent OR' and the hydrolyzable group Y is a substituent NR'. Y The monoalkyltin compound according to any one of

[15] to

[18] , wherein R is 2.

[20] Monoalkyltin compound RSnX ３ 50 to 99.99 mol % of (A1), RSnX ２ A monoalkyltin composition containing 0.01 mol % or more and less than 50 mol % of Y(B1). (In the general formulas (A1) and (B1), R is an organic group having 1 to 30 carbon atoms. X and Y are hydrolyzable groups having different chemical formulas, and X is one of OR', NR', 2、 C≡CR', and said Y is OR' Y , NR' Y 2、 C≡CR' Y The R' and R' are selected from the group consisting of Y is an organic group having 1 to 10 carbon atoms. When X is NR'2 and / or Y is NR'2, R', R' Y may be the same or different. Y When there are a plurality of groups, they may have different structures, or may be bonded to each other to form a cyclic structure.)

[21] Monoalkyltin compound RSnX ３(A1) in an amount of 0.01 mol% or more and less than 50 mol%, RSnX ２ A monoalkyltin composition containing 50 to 99.99 mol % or less of Y(B1). (In the general formulas (A1) and (B1), R is an organic group having 1 to 30 carbon atoms. X and Y are hydrolyzable groups having different chemical formulas, and X is one of OR', NR', 2、 C≡CR', and said Y is OR' Y , NR' Y 2、 C≡CR' Y The R' and R' are selected from the group consisting of Y is an organic group having 1 to 10 carbon atoms. When X is NR'2 and / or Y is NR'2, R', R' Y may be the same or different. YWhen there are a plurality of RSnX3 (A1), RSnX2Y (B1), and a monoalkyltin compound other than these, the structures may be different from each other, or they may be bonded to each other to form a cyclic structure.)

[22] The monoalkyltin composition according to

[20] or

[21] , comprising RSnX3 (A1), RSnX2Y (B1), and a monoalkyltin compound other than these, wherein the sum of the contents of RSnX3 (A1) and RSnX2Y (B1) is 80 mol % or more.

[23] A method for producing a tin compound having a tin atom, an organic group R, and an oxo ligand and / or a hydroxo ligand, wherein the diffraction angle 2θ (°) of the peak of maximum intensity in X-ray diffraction measurement is between 5.00 and 15.00° and the half-width of the maximum intensity peak is between 1.00 and 4.00°, and the organic group R has 1 to 30 carbon atoms, the method comprising the following steps 1 and 2: <Step 1> Using the monoalkyl tin composition according to

[20] or

[21] as a raw material. <Step 2> Contacting the raw material with water and / or water vapor.

[24] The method for producing a tin compound according to

[23] , wherein in step 2, a blend of the raw material and an organic solvent is contacted with liquid water.

[25] The method for producing a tin compound according to

[23] or

[24] , comprising in step 2 blending 100 parts by mass or more of an organic solvent with 100 parts by mass of the raw material to obtain a composition.

[26] The method for producing a tin compound according to any of

[23] to

[25] , wherein the half-width at the maximum intensity peak is 1.43 to 4.00°.

[0013] The tin compound of the present invention has high purity and uniform solubility, and is therefore useful as a high-performance resist material.

[0014] Figure 1 is an XRD chart of tin hydrolysate H1A. Figure 2 is an XRD chart of tin hydrolysate H1C. Figure 3A is an XRD chart of tin hydrolysate H1A. 119 Figure 3B is a wide-range chart of Sn-NMR of tin hydrolysate H1A. 119 FIG. 3C is a detailed chart of Sn-NMR of tin hydrolyzate H1A. 13D is a chart of electrospray ionization mass spectrometry (ESI-MS) of tin hydrolysate H1A.

[0015] The present invention will be described below based on examples of embodiments for carrying out the present invention. However, the present invention is not limited to the embodiments described below. In the present invention, when "α to β" (α and β are arbitrary numbers) is used, it means "α or more and β or less," unless otherwise specified, and also includes "preferably more than α" or "preferably less than β." In the present invention, when "α or more" (α is an arbitrary number) or "β or less" (β is an arbitrary number) is used, it also includes "preferably more than α" or "preferably less than β." In the present invention, "γ and / or δ (γ and δ are arbitrary constituents or components)" refers to three combinations: γ only, δ only, and γ and δ. Regarding the numerical ranges described in stages in the present invention, the upper or lower limit of a certain numerical range can be arbitrarily combined with the upper or lower limit of another numerical range. Furthermore, in the numerical ranges described herein, the upper or lower limit of the numerical range can be replaced with the values ​​shown in the examples. In the present invention, the term "main component" means a component that has a significant effect on the properties of the target object, and the content of the component is usually 50% by mass or more, preferably 55% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, and may be 100% by mass.

[0016] The tin compound according to one embodiment of the present invention will be described in detail below.

[0017] <<Present Tin Hydrolysate>> The tin compound (P1) according to one embodiment of the present invention is a tin compound having a tin atom, an organic group R, and an oxo ligand and / or a hydroxo ligand, wherein the organic group R has 1 to 30 carbon atoms. Hereinafter, the substituent bonded to the tin atom may be referred to as a ligand.

[0018] In X-ray diffraction measurement of the compound (P1), the diffraction angle 2θ (°) of the maximum intensity peak is between 5.00 and 15.00°, and the half-width at the maximum intensity peak is between 1.00 and 4.00°. In this embodiment, an object of the present invention is to provide a high-performance resist material that can have particularly high purity and uniform solubility. To achieve this object, tin compounds RSnX having different hydrolyzable groups are used as precursors in order to simultaneously control the crystallinity and purity of the hydrolyzate. ２ It was discovered that deliberately including Y was effective.

[0019] For convenience, the tin compound (P1) of the present embodiment may be referred to as the "present tin hydrolysate."

[0020] Specifically, the present tin hydrolyzate (P1) is a tin compound having a tin atom, an organic group R, and an oxo ligand and / or a hydroxo ligand. In this embodiment, each tin atom typically has a ligand (sometimes referred to as a "substituent") selected from the group consisting of an organic group R, an oxo ligand (Sn—O structure, Sn═O structure), and a hydroxo ligand (Sn—OH structure). The present tin hydrolyzate (P1) may have two or more types of organic group R per molecule, and one tin atom may have multiple types of organic group R. However, the effects of the present invention tend to be more effectively achieved when the tin compound contains only one type of organic group R with a single chemical structure. The present tin hydrolyzate (P1) is typically formed from the above-mentioned metal and ligand, but may also contain other metal atoms and ligands (substituents) as long as their properties are not impaired.

[0021] The tin hydrolyzate (P1) is synthesized by hydrolysis of RSnX or RSnXY (monoalkyltin compounds, sometimes referred to as "precursors") as the main raw material, for example, using a method such as that disclosed in JP 2021-21953 A. (X is a hydrolyzable group [a substituent that can form an oxo ligand (Sn—O structure) or a hydroxo ligand (Sn—OH structure) by hydrolysis].)

[0022] Specifically, tin compounds such as tin hydrolysates (P2) represented by the following compositional formula are obtained by hydrolyzing or condensing RSnX or RSnXY with water or other suitable reagents under appropriate conditions. Compounds represented by this compositional formula include RSnOOH and RSn(OH) which are hydrolysates of RSnX or RSnXY, and condensates which contain tin atoms and organic groups and include oxo and / or hydroxo ligands. For example, they include compounds in which tin atoms (optionally having hydroxo ligands) with organic groups form a network structure via the oxo ligands. [Formula] RSnO (1.5-(x / 2)) (OH) x (In the formula, 0≦x≦3)...(P2)

[0023] The reaction formula for obtaining the tin hydrolyzate (P2) is shown below. Examples of reaction formulas using RSnX3 and RSnX2Y are shown below. (Reaction Formula 1) RSnX3 + 3H2O → RSn(OH)3 + 3HX RSn(OH)3 → RSnO (1.5-(x / 2)) OH x + (x / 2) H2O (Reaction formula 2) RSnX2Y + 3H2O → RSn(OH)3 + 2HX + HY RSn(OH)3 → RSnO (1.5-(x / 2)) OH x + (x / 2) H2O

[0024] In these reaction formulas, when a precursor such as RSnXY containing multiple hydrolyzable groups X and Y in one molecule is used, the hydrolyzable groups X and Y react with water at different reaction rates. As a result, the composition, structure, crystallinity, purity, etc. of the tin hydrolyzate produced by the reaction may be affected. In particular, by using a precursor mixture containing RSnX and RSnXY, which have similar structures, (Reaction Formula 1) and (Reaction Formula 2) can be carried out simultaneously in the reaction system, and by using the two reaction formulas in combination, a tin hydrolyzate with more appropriate composition, crystallinity, and purity can be formed.

[0025] Furthermore, although the above reaction contains by-products HX and HY after hydrolysis, when these are removed during the process (filtration, washing, heating, drying, volatilization, etc.), no unnecessary impurities remain in the tin hydrolyzate. Other tin compounds (e.g., tin compounds such as RSnX(A2) and SnX(A3)) may similarly affect the control of crystallinity, etc., but when these tin compounds are incorporated into the resulting tin hydrolyzate, they may change the structure and number of alkyl groups in the tin hydrolyzate, potentially causing problems as a resist material (reduced purity, generation of foreign matter, increased outgassing, reduced sensitivity, increased roughness, etc.). Therefore, the use of RSnXY in combination is preferable because it allows for control of the composition, structure, crystallinity, etc. of the tin hydrolyzate without causing the aforementioned problems as a resist material.

[0026] Among the compounds shown in this tin hydrolysate (P1), tin compounds having a specific structure and number of tin atoms may be used as high-performance resist materials. For example, a compound containing a tin dodecamer represented by the chemical formula shown below (tin hydrolysate (P3)) is a stable football-shaped tin dodecamer cluster compound and is useful as a resist material. It is a cationic compound with the chemical formula shown below. [Formula] (RSn) 12 O 14 (OH)6 +2 ...(P3) (In the above formula, +2 represents a divalent cation.)

[0027] The tin hydrolysate (P3) is generally a divalent cationic compound that is stabilized by a counter anion (Z), and when combined with a monovalent counter anion (Z), the salt has the following chemical formula: [Formula] (RSn) 12 O 14 (OH)6(Z)2

[0028] The counter anion (Z) is not particularly limited, and examples thereof include an OH anion, an RCO2 anion, an HCO2 anion, an F anion, and a Cl anion.

[0029] As a specific example of the tin hydrolysate (P3), the synthesis examples described in the following literature are known: (nBuSn) 12 O 14 (OH)6 +2 A report on the synthesis of: Eychenne-Baron et al., "New synthesis of the nanobuilding block {(BuSn) 12 O 14 (OH) 2+ and exchange properties of {(BuSn) 12 O 14 (OH)6}(O3SC6H4CH3)2", J. Organometallic Chemistry 1998, 567, 137-142

[0030] (iPrSn) 12 O 14 (OH)6 +2 Synthesis report: Puff et al. , "Zur hydrolyse von monoorganylzinn-tri halogeniden (III. mit dem nueartigen Kaefig-ion [(i-PrSn) 12 O 14 (OH)6 +2 These compounds have been identified by NMR, single crystal X-ray structure, etc., and the analytical results are cited as support in the examples of the present invention.

[0031] [Organic Group R] The tin hydrolysates (P1, P2, P3, hereinafter) contain an organic group R bonded to a Sn atom. The organic group R has 1 to 30 carbon atoms. Considering the ease of elimination of the R group during EUV exposure and the vaporization of the generated component having the R group, the upper limit of the number of carbon atoms in the organic group R is 30 or less, preferably 20 or less, and more preferably 10 or less. From the viewpoint of the stability of the elimination component, the lower limit is 1 or more, preferably 2 or more, and more preferably 3 or more. Examples of the organic group R include halogenated hydrocarbon groups, hydrocarbon groups containing heteroatoms such as oxygen atoms and nitrogen atoms, and hydrocarbon groups, which can be used alone or in combination of two or more. Among these, hydrocarbon groups are preferred because, when used as a resist, the outgassing generated upon elimination after exposure is hydrocarbon, which has minimal impact on semiconductor devices. On the other hand, the inclusion of heteroatoms may result in higher decomposition properties with respect to EUV light and improved resist performance, such as sensitivity.

[0032] When the organic group R is a hydrocarbon group, preferred specific examples of the hydrocarbon group include primary alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, and n-hexyl groups, secondary alkyl groups such as isopropyl, isobutyl, sec-butyl, and isopentyl groups, tertiary alkyl groups such as t-butyl, t-amyl, cyclopentyl, cyclohexyl, methylcyclopentyl, and methylcyclohexyl groups, aryl groups such as phenyl, tolyl, benzyl, and naphthyl groups, aromatic hydrocarbon groups such as aralkyl groups such as phenethyl, α-methylbenzyl, and 2-phenyl-2-propyl groups, alkenyl groups such as vinyl, 1-propenyl, allyl, and 3-butenyl groups, and alkyl groups substituted with a halogen atom such as 2-fluoroethyl and 2-iodoethyl groups.

[0033] Further examples of the structure include the following compounds: a and R bis an organic group having 1 to 10 carbon atoms, and examples of the organic group R include halogenated hydrocarbon groups, hydrocarbon groups containing heteroatoms such as oxygen atoms and nitrogen atoms, and hydrocarbon groups. These can be used alone or in combination of two or more types, but from the viewpoint of effectively achieving the effects of the present invention, it is preferable to use only one type, excluding two or more types. Among these, hydrocarbon groups are preferred because, when used as a resist, the outgas generated when desorbed after exposure is hydrocarbon, and they have little impact on semiconductor devices. The substituent A on the aromatic ring is a halogen atom or an organic group having 1 to 10 carbon atoms, and examples of such organic groups include hydrocarbon groups containing heteroatoms such as nitrogen atoms, and hydrocarbon groups, with hydrocarbon groups being preferred.

[0034]

[0035]

[0036] (Preferred Hydrocarbon Group) Among the hydrocarbon groups shown above, the primary hydrocarbon group R 1 , a secondary hydrocarbon group R 2 , a tertiary hydrocarbon group R 3 a cyclic hydrocarbon group R c These hydrocarbon groups are classified into saturated hydrocarbon groups and unsaturated hydrocarbon groups such as , and may exhibit different properties when used as a resist material. When the hydrocarbon group is a saturated hydrocarbon group, it is preferred from the viewpoint of sensitivity (photoreactivity). In each classification, preferred substituents include primary hydrocarbon groups R 1 , a secondary hydrocarbon group R 2 , a tertiary hydrocarbon group R 3 From the viewpoint of sensitivity (photoreactivity) when used in an EUV resist, a secondary hydrocarbon group R that is easily eliminated is preferred. 2 , a tertiary hydrocarbon group R 3 is preferred, and the tertiary hydrocarbon group R 3 From the viewpoint of hydrophobicity, the tertiary hydrocarbon group R 3 is preferred from the viewpoint of controlling solubility because it can most effectively increase the hydrophobicity in the vicinity of the tin atom. However, if the hydrophobicity is too high, the secondary hydrocarbon group R 2 may be preferred.

[0037] [Composition Analysis of the Tin Hydrolysate] The tin hydrolysate was analyzed by NMR ( 1 H-NMR, 13 C-NMR, 119 The composition of the contained substituents can be analyzed using analytical devices such as Sn-NMR and their correlation NMR, mass spectrometry, etc. NMR can analyze the composition of the entire sample, and can analyze information such as the ligands of the tin atom (substituent R, etc.) and the coordination number per tin atom, thereby enabling the structural identification of the substituent R and the quantification of the average composition of the substituent R in the sample.

[0038] of this tin hydrolysate 119 In Sn-NMR, the ratio (k1 / k2) of the total peak integrals (k1) of pentacoordinate Sn (-250 to -350 ppm) to the total peak integrals (k2) of hexacoordinate Sn (-450 to -600 ppm) is preferably 0.5 to 2.5, more preferably 1.0 to 2.4, even more preferably 1.2 to 2.3, and particularly preferably 1.3 to 2.2. In this tin hydrolysate, pentacoordinate Sn tends to have OH groups, while hexacoordinate Sn tends to have more coordination moieties and therefore to have only Sn—O—Sn bonds with no OH groups bonded. In other words, the higher the k1 / k2 value, the greater the number of OH groups, and the lower the value, the fewer the number of OH groups. The number of OH groups affects the polarity of the tin compound, which affects its solubility in resist solvents, and the hydrophobicity and hydrophilicity parameters of the tin compound, which affect resist performance. From the viewpoint of controlling the balance of performance, it is preferable that k1 / k2 is controlled within the above range.

[0039] In mass analysis (mass spectrometry, sometimes referred to as "MS") (ESI-mass analysis (electrospray ionization) is particularly preferred from the viewpoint of sensitivity and the ability to detect unstable compounds through soft ionization), the molecular weight and molecular formula of the compound contained in the tin compound can be identified from the molecular weight of the ions observed. In other words, while what is observed in NMR is the average composition of the entire sample, the composition of the organic group R observed in mass analysis represents the composition of the organic group R contained in one molecule. Furthermore, by quantifying the intensity of each peak, it is possible to detect the composition with the highest concentration of the organic group R contained in one molecule. Examples of these analyses are also given in the Examples section.

[0040] (Purity of the present tin hydrolysate) The method for calculating the purity of the (tin hydrolysate) by NMR is shown below. Here, the "mol %" expressed in terms of tin atoms, which represents the purity, is the ratio of tin atoms of the target compound to the number of tin atoms of all compounds containing tin atoms (including unidentified compounds). In practice, 119 The calculation is performed by using the sum of the integral values ​​of all peaks observed by Sn-NMR as the denominator and the integral value of the peak of the target compound as the numerator. 119 The measurement range of Sn-NMR is 1000 to -1000 ppm, which is a range in which the compounds to be analyzed can be sufficiently measured. For example, the purity of the tin hydrolyzate composed of five-coordinate Sn and six-coordinate Sn is as follows: 119 Five-coordinate Sn in Sn-NMR 119 The sum of the integral values ​​of the peaks of five-coordinate Sn (-250 to -350 ppm) in Sn-NMR (k1) and the integral value of the peaks of six-coordinate Sn (-450 to -600 ppm) (k2) is expressed as (k1+k2), 119When k3 is the sum of all integrals of other peaks detected by Sn-NMR (in the range of 1000 to -1000 ppm, including k1 and k2), k1 is expressed as (k1 + k2) / (k3). The larger this value, the lower the concentration of impurities other than pentacoordinate Sn and hexacoordinate Sn in the tin hydrolyzate, and therefore, it is preferable. The lower limit is preferably 0.7 or more, more preferably 0.8 or more, even more preferably 0.9 or more, particularly preferably 0.95 or more, and most preferably 0.99 or more. From the viewpoint of the measurement sensitivity of this method, if no peaks corresponding to k1 and k2 can be detected, it can be considered as 0.99 or more. The upper limit is 1.

[0041] According to this calculation method, only compounds containing tin atoms are included in the calculation. For example, even if additives or solvents are added according to the intended use after the present tin hydrolyzate is produced, the present tin hydrolyzate and other impurities such as tin compounds are included in the range of the present tin hydrolyzate as long as they contain the present tin hydrolyzate.

[0042] 119 In order to improve sensitivity, the Sn-NMR analysis method involves dissolving the tin hydrolyzate at a high concentration and performing the analysis (using a solvent that dissolves the tin at a high concentration). The analysis was performed using a large number of integration times (1,000 or more, preferably 10,000 or more), sufficient relaxation time (1 second or more), reverse gate decoupling, and an appropriate measurement range (1,000 to -1,000 ppm). As a result, by using these methods, the detection limit for trace amounts of tin compounds can reach 0.01 mol%. In addition, if the sensitivity of the measurement peak is still insufficient, the detection sensitivity can be further increased to 0.001 mol% by using a high-sensitivity NMR (for example, a cryoprobe with 600 MHz NMR). Examples of these analyses are also illustrated in the Examples section.

[0043] ​[Crystallization of the Present Tin Hydrolysate] The present tin hydrolysate is preferably solid in order to form a thin film as a resist material and to have resistance to semiconductor processes (exposure, development, etching, etc.). In particular, controlling the properties of the solid, i.e., particle size, shape, crystallinity, and surface condition, within specific ranges may be preferable as a resist material. Crystallinity is particularly important because it allows for control of solubility (which contributes to development performance, coating performance, ease of filtration, and storage stability of the resist solution) and the solid's surface condition (which contributes to hydrophobicity / hydrophilicity, substrate adhesion, etc.) while maintaining the properties derived from the chemical formula. In addition, crystallinity affects adhesion when applied to a substrate, post-exposure roughness and susceptibility to pattern collapse, solubility during development, and other factors, so it must be appropriately controlled within the range required for resist performance. Specifically, if the crystallinity is too high, dissolution in the resist solvent becomes difficult, causing problems during processes such as dissolution, filtration, and storage. Furthermore, if the crystallinity is too high during application and drying, cracking or collapse of the pattern may occur at the interface between crystals or on the crystal surface. During exposure and development, high crystallinity and large crystal size can lead to increased pattern roughness after development. On the other hand, if the crystallinity is too low, the resist film may have poor adhesion to the substrate or low strength, which can lead to peeling of the resist film during application, drying, exposure, development, etc., the pattern may collapse, or the pattern may become rough after development. As such, in resist materials with excellent solubility, adhesion, and roughness, an appropriate range of crystallinity exists, so it is necessary to appropriately control the ratio of crystalline components to amorphous components (non-crystalline) and control it within a specific crystallinity range.

[0044] Crystallinity can be analyzed by XRD (X-ray diffraction measurement), which can be applied to the tin hydrolyzate in the form of powder, molded body, thin film, or patterned thin film after exposure. Among the values ​​obtained from XRD, the diffraction angle 2θ (°) at the maximum intensity peak, the half-width (°) at the maximum intensity peak, and the number of detected peak tops can be used as numerical values ​​representing the crystallinity of the resulting tin compound. The analytical accuracy shown in this example is valid up to two decimal places, and when comparing the diffraction angle 2θ (°) and half-width (°), values ​​of 0.01 (°) or greater can be considered significant. Specific measurement methods are also shown in the examples.

[0045] The diffraction angle 2θ (°) of the peak with maximum intensity of the present tin hydrolyzate is preferably 5.00 to 15.00°, with the upper limit more preferably 13.00° or less, even more preferably 11.00° or less, particularly preferably 10.00° or less, and especially preferably 9.00° or less. The lower limit is more preferably 5.50° or more, even more preferably 5.80° or more, and particularly preferably 6.00° or more. The diffraction angle 2θ (°) of the peak with maximum intensity correlates with the lattice spacing of the crystals, and when it is in the above preferred range, the crystals of the present tin compound are arranged with an appropriate lattice spacing, and as crystals with appropriate crystallinity and strength during pattern formation, it is possible to suppress pattern collapse and simultaneously reduce roughness during fine pattern formation.

[0046] The half-width (°) at the maximum intensity peak is preferably in the range of 1.00 to 4.00°, with the upper limit being more preferably 3.50° or less, particularly preferably 3.00° or less, particularly preferably 2.50° or less, and particularly preferably 2.00° or less. The lower limit is more preferably 1.05° or more, even more preferably 1.10° or more, particularly preferably 1.20° or more, particularly preferably 1.43° or more, and particularly preferably 1.50° or more. The half-width (°) at the maximum intensity peak is particularly strongly correlated with the crystallinity of the tin compound, and when the half-width (°) is in the above-mentioned preferred range, parameters such as the solubility required for the resist material (contributing to development performance, coating performance, ease of filtration process, and storage stability of the resist solution) and the surface state of the solid (contributing to hydrophobicity / hydrophilicity, substrate adhesion, etc.) can be controlled within appropriate ranges.

[0047] The number of peak tops detected in the diffraction angle 2θ (°) range of 5.00 to 15.00° is preferably 5 or less, more preferably 3 or less, more preferably 2 or less, and most preferably 1 or less. The lower limit is preferably 1 or more. Note that 0 indicates that no peak tops are detected by the above analytical method. For the present tin hydrolysate, the fewer the number of peak tops, the lower the crystallinity tends to be; however, 0 peak tops indicates that no crystalline structure is detected at all. In other words, when the number of peak tops is within the above preferred range, the resist material has appropriate crystallinity, and parameters such as solubility (contributing to development performance, coating performance, ease of filtration process, and storage stability of the resist solution) and solid surface condition (contributing to hydrophobicity / hydrophilicity, substrate adhesion, etc.) required for the resist material can be controlled within appropriate ranges.

[0048] [Solubility of the Present Tin Hydrolysate] When used as a resist material, the present tin hydrolysate may be dissolved in the resist solvent described below and used as a resist solution. The solubility of the present tin hydrolysate refers to the solubility when dissolved in the organic solvent used to prepare the resist solution. After dissolution, the resist solution is preferably completely dissolved, free of insoluble matter and turbidity derived from the present tin hydrolysate. Insoluble matter derived from the present tin hydrolysate can cause performance degradation and problems when used as a resist material. Specific examples include defects during patterning, resulting in performance degradation as a resist material (causing line width roughness (LWR), pattern collapse, and reduced sensitivity), equipment contamination due to impurities and foreign matter generated during etching, and clogging and reduced productivity in the filtration process.

[0049] (Resist Solvent) The tin hydrolyzate is dissolved in a resist solvent, which may be an organic solvent such as an alcohol, an ester, or a combination thereof. Particularly suitable solvents include aromatic compounds (e.g., xylene, toluene), ethers (anisole, tetrahydrofuran), halogenated solvents (dichloromethane, chloroform), esters (propylene glycol monomethyl ether acetate, ethyl acetate, ethyl lactate), alcohols (e.g., 4-methyl-2-pentanol, 4-methyl-2-propanol, 1-butanol, methanol, isopropyl alcohol, 1-propanol), and mixtures of ketones (e.g., methyl ethyl ketone, cyclohexanone, 2-heptanone). These solvents may be used alone or in combination. Among these, alcoholic solvents are preferred for dissolving tin hydrolyzates having OH groups, with 4-methyl-2-pentanol being more preferred. From the viewpoints of toxicity, legal regulations, and volatility, 2-heptanone, 4-methyl-2-pentanol, and ethyl lactate are also preferred solvents in practical manufacturing processes.

[0050] The selection of these resist solvents may be based on the physical properties of the solvent itself, such as solubility parameter, volatility, flammability, toxicity, and viscosity. Alternatively, the resist solvent may be evaluated based on its stability (dissolution stability) when a tin hydrolyzate or other material is dissolved in the resist solvent. That is, after the components of the resist solution are dissolved and mixed, the properties of the dissolved tin hydrolyzate may change as a result of partial interactions (reaction, condensation, solvation, coordination, etc.) between the tin hydrolyzate and the solvent, particularly during the period from solution preparation to film formation. Solution stability due to these interactions is evaluated based on the storage stability of the resist solution, as described below. From the viewpoint of storage stability, alcoholic solvents are preferred due to stabilization through coordination with OH groups.

[0051] (Method for Evaluating Solubility) The solubility of the present tin hydrolysate was evaluated by comparing the turbidity (clarity) when the tin hydrolysate was dissolved at a certain concentration in 4-methyl-2-pentanol. Specifically, a mixed solution of 2.0% by mass of the tin hydrolysate in 4-methyl-2-pentanol was prepared as disclosed in JP-A-2019-500490, and the turbidity (clarity) of the resulting solution was visually confirmed by comparison with a standard turbidity solution to evaluate the solubility of the corresponding present tin hydrolysate. Kaolin turbidity standard solutions (0°C (clear), 50°C, 100°C, 500°C, 1000°C (white turbidity)) specified in JIS K0110 were used as the standard turbidity solutions, and the turbidity closest to that of each standard turbidity solution was evaluated as turbidity ratings 1 to 5 as follows: Turbidity rating 1: 0 degrees (transparent) Turbidity rating 2: 50 degrees Turbidity rating 3: 100 degrees Turbidity rating 4: 500 degrees Turbidity rating 5: 1000 degrees (cloudy)

[0052] [Storage Stability of Resist Solution] The resist solution prepared by dissolving the present tin hydrolyzate is required to be stable without stirring for at least one week, preferably two weeks or more, more preferably one month or more, even more preferably three months or more, and particularly preferably six months or more, without solid precipitation or sedimentation. A specific method for evaluating storage stability is to store the above solution sample at 20°C and perform a similar turbidity evaluation one week, two weeks, and one month after dissolution. For a resist solution to be stably stored, it is preferable that there be no change in turbidity in this evaluation.

[0053] <<Raw Materials for the Tin Hydrolysate>> In producing the tin hydrolysate as described above, it is preferable to use the monoalkyltin compounds (A1) and (B1) shown below as raw materials (sometimes referred to as "precursors"), although there are no particular limitations. The monoalkyltin compounds (A1) and (B1) that can be used as precursors are described below.

[0054] <Monoalkyltin Compound (A1)> The monoalkyltin compound (A1) is defined as follows. It is a compound in which one organic group and three hydrolyzable groups X capable of undergoing a reaction such as hydrolysis are bonded to tetravalent tin. Specifically, it is represented by the following general formula (A1): RSnX3... (A1) (In the general formula (A1), R is an organic group having 1 to 30 carbon atoms. X is selected from OR', NR'2, and C≡CR'. R' is an organic group having 1 to 10 carbon atoms. When there are multiple R's in a molecule, they may have different structures or may be bonded to each other to form a cyclic structure.)

[0055] [Organic Group R] The organic group R has 1 to 30 carbon atoms. Examples of the organic group R include halogenated hydrocarbon groups, hydrocarbon groups containing heteroatoms such as oxygen and nitrogen atoms, and hydrocarbon groups. These groups can be used alone or in combination of two or more. From the viewpoint of effectively achieving the effects of the present invention, using these groups alone (excluding the use of two or more groups in combination) is preferred. Among these, hydrocarbon groups are preferred because, when used as a resist, the outgas generated upon elimination after exposure is hydrocarbon, and they have minimal impact on semiconductor devices. When a heteroatom is contained, the group exhibits high decomposition properties with respect to EUV light, which may improve resist performance such as sensitivity. Considering the ease of elimination of the R group and vaporization of the generated R group component during EUV exposure, the upper limit of the number of carbon atoms in R is 30 or less, preferably 20 or less, and more preferably 10 or less. From the viewpoint of the stability of the elimination component, the lower limit is 1 or more, preferably 2 or more, and more preferably 3 or more.

[0056] The organic group R is preferably a hydrocarbon group, since when used as a resist, the outgassing generated upon desorption after exposure is hydrocarbon, and the impact on the semiconductor device is minimal. Specific examples of preferred hydrocarbon groups include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, t-butyl, pentyl, hexyl, cyclopentyl, and cyclohexyl; aryl groups such as phenyl, tolyl, benzyl, and naphthyl; aromatic hydrocarbon groups such as aralkyl groups such as phenethyl, α-methylbenzyl, and 2-phenyl-2-propyl; alkenyl groups such as vinyl, 1-propenyl, allyl, and 3-butenyl; and alkyl groups substituted with halogen atoms such as 2-fluoroethyl and 2-iodoethyl. These groups may be used alone or in combination of two or more.

[0057] Further examples of the structure include the following compounds: a and R bis an organic group having 1 to 10 carbon atoms. Examples of such organic groups include halogenated hydrocarbon groups, hydrocarbon groups containing hetero atoms such as oxygen atoms and nitrogen atoms, and hydrocarbon groups. The substituent A on the aromatic ring is a halogen atom or an organic group having 1 to 10 carbon atoms. Examples of such organic groups include hydrocarbon groups containing hetero atoms such as oxygen atoms and nitrogen atoms, and hydrocarbon groups.

[0058]

[0059]

[0060] The hydrocarbon groups shown above are primary hydrocarbon groups R 1 , a secondary hydrocarbon group R 2 , a tertiary hydrocarbon group R 3 and are typically alkyl or aralkyl groups. Preferred examples of each group include primary hydrocarbon groups R 1 R: a secondary hydrocarbon group such as a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an isobutyl group, a benzyl group, or a phenethyl group 2 R: a tertiary hydrocarbon group such as an isopropyl group, a sec-butyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, or an α-methylbenzyl group 3 Examples of such groups include t-butyl, t-amyl, 1-methyl-cyclopentyl, 1-methyl-cyclohexyl, and 2-phenyl-2-propyl groups. Each group may exhibit different properties when used in a resist material. The following describes hydrocarbon groups as representative examples. From the viewpoint of sensitivity (photoreactivity) when used in a preferred EUV resist, the secondary hydrocarbon group R that is easily eliminated is selected. 2 , a tertiary hydrocarbon group R 3 From the viewpoint of hydrophobicity, the tertiary hydrocarbon group R 3 is most preferable from the viewpoint of controlling solubility because it can increase the hydrophobicity in the vicinity of the tin atom. However, if the hydrophobicity is too high, the secondary hydrocarbon group R 2is sometimes preferable. Furthermore, from the viewpoint of thermal stability, which affects distillation and the like, primary hydrocarbon groups tend to be less susceptible to disproportionation and the like, and may be easily purified. On the other hand, secondary and tertiary hydrocarbon groups are prone to disproportionation reactions, and secondary and tertiary hydrocarbon groups having a small carbon number (6 or less) in particular are unstable during distillation, and distillation with high purification efficiency is often difficult due to thermal decomposition and the like. Therefore, it is more important to obtain a high-purity tin compound with a low content of by-products with similar boiling points in the reaction stage prior to purification such as distillation.

[0061] [Substituent X] The structure of the substituent X is not particularly limited as long as it is a hydrolyzable group that can undergo a reaction such as hydrolysis. Preferred examples of the substituent X include OR', NR'2, and C≡CR' in terms of high reactivity, with OR' and NR'2 being more preferred in terms of hydrolysis reactivity. R' is an organic group having 1 to 10 carbon atoms, and examples of the organic group include halogenated hydrocarbon groups, hydrocarbon groups containing heteroatoms such as oxygen atoms and nitrogen atoms, and hydrocarbon groups. Furthermore, when there are multiple R's in a molecule, the structures may be different from each other, or they may be bonded to each other to form a cyclic structure. Among these, an alkoxy group is preferred as OR', and an alkylamino group is preferred as NR'2, in terms of the balance between high reactivity upon hydrolysis and stability during synthesis. Specific examples of the organic group R' include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, a t-amyl group, a 2-methyl-pentyl group, a trifluoroethyl group, and a trifluoromethyl group. Examples of NR'2 include a 1-pyrrolidinyl group in which two substituents on the nitrogen are bonded to form a five-membered ring.

[0062] As a preferred substituent X, an alkyl group containing no heteroatoms or an alkyl group containing fluorine is preferred as the organic group R' from the viewpoint of low boiling point and stability. Furthermore, from the viewpoint of low boiling point, a smaller number of carbon atoms is preferred, while from the viewpoint of thermal stability and stability against moisture, a larger number of carbon atoms is preferred. Specific examples of substituent X that have an excellent balance of these properties include OR': t-butoxy group, t-amyloxy group, 4-methyl-2-pentaloxy group, trifluoroethoxy group, trifluoromethoxy group; and NR'2: dimethylamino group, diethylamino group, methylethylamino group, pyrrolidyl group, etc. Among these, OR' is preferred from the viewpoint of hydrolysis reactivity when used as a resist material, with dimethylamino group and diethylamino group being most preferred. NR'2 is preferred from the viewpoint of balance between stability and reactivity, with t-butoxy group, t-amyloxy group, and 4-methyl-2-pentaloxy group being most preferred.

[0063] Furthermore, R in the molecule and the organic group contained in the substituent X may be bonded to each other to form a cyclic structure. In this case, for example, compounds having the structure shown below may be mentioned.

[0064]

[0065] [Structure of Monoalkyltin Compound (A1)] The structure and physical properties of the monoalkyltin compound (A1) (hereinafter sometimes referred to as "tin compound (A1)") are not particularly limited as long as they fall within the above-mentioned ranges. However, when used as an EUV resist material, it may be preferable for the compound to have the following physical properties.

[0066] (Boiling point) When using the tin compound (A1), the boiling point at 1 torr is preferably 300°C or less, more preferably 250°C or less, even more preferably 200°C or less, and particularly preferably 150°C or less. The lower limit of the boiling point at 1 torr is usually 0°C or more, preferably 10°C or more, more preferably 20°C or more. A low boiling point allows distillation at low temperatures, which is preferable from the viewpoint of facilitating deposition when used as a resist material. When the boiling point is above the above lower limit, processes involving deposition and reaction at high temperatures tend to be easier when used as an EUV resist, and the thermal stability of the formed film tends to be excellent, which tends to suppress volatilization and scattering of components and outgassing.

[0067] (Molecular Weight) The molecular weight of the tin compound (A1) is preferably 500 or less, more preferably 400 or less, and even more preferably 350 or less. The lower limit is preferably 150 or more, more preferably 180 or more, and even more preferably 200 or more. If the molecular weight is too high, the boiling point becomes too high, which may make deposition difficult when used as an EUV resist. If the molecular weight is too low, the boiling point becomes too low, which may make processes involving deposition or reaction at high temperatures difficult, or the thermal stability of the formed film may be insufficient, causing problems such as volatilization and scattering of components and outgassing.

[0068] (Molecular Weight Difference Between Organic Group R and Substituent X) There is no particular limitation on the molecular weight difference between the organic group R and the substituent X, but it is preferably 50 or less, more preferably 30 or less, even more preferably 20 or less, particularly preferably 10 or less, and especially preferably 6 or less. The lower limit is 0. By reducing the molecular weight difference between R and X, the mass difference of various outgases generated when used as a resist tends to be reduced, making it easier to set conditions in the EUV process. Furthermore, in order to control the EUV sensitivity and boiling point of the tin compound, the molecular weight difference may be adjusted by changing the substituent. On the other hand, as described below, the smaller the molecular weight difference between R and X, the smaller the molecular weight difference between the tin compound (A1) and impurities, which may make purification more difficult.

[0069] <Tin Compound (B1)> One embodiment of the present invention is a tin compound (B1) of RSnX2Y. The tin compound (B1) of RSnX2Y is defined as follows: It is a compound in which one organic group R, two hydrolyzable groups X capable of undergoing a reaction such as hydrolysis, and one hydrolyzable group Y are bonded to tetravalent tin. Specifically, it is represented by the following general formula (B1): RSnX2Y ... (B1)

[0070] In the general formula (B1), R is an organic group having 1 to 30 carbon atoms, and examples of the organic group include halogenated hydrocarbon groups, hydrocarbon groups containing heteroatoms such as oxygen atoms and nitrogen atoms, and hydrocarbon groups, which can be used alone or in combination of two or more. Among these, hydrocarbon groups are preferred because, when used as a resist, the outgas generated when desorbed after exposure is a hydrocarbon, and they have little effect on semiconductor devices. X and Y are hydrolyzable groups with different chemical formulas, and X is a group selected from the group consisting of OR', NR', 2、 C≡CR', and said Y is OR' Y , NR' Y 2、 C≡CR' Y The R' and R' are selected from the group consisting of Y is an organic group having 1 to 10 carbon atoms. Examples of the organic group include halogenated hydrocarbon groups, hydrocarbon groups containing heteroatoms such as oxygen atoms and nitrogen atoms, and hydrocarbon groups, which can be used alone or in combination of two or more. Among these, hydrocarbon groups are preferred. X is NR'2 and / or Y is NR' Y In the case of 2, the R' and R' Y may be the same or different. Y When there are a plurality of groups, they may have different structures, or may be bonded to each other to form a cyclic structure.

[0071] In this embodiment, an object is to provide a high-performance resist material that can have particularly high purity and uniform solubility. ３ When used as a precursor, the tin compound RSnX２ It was found that by adding Y, it is possible to control the crystallinity of the hydrolyzate without reducing the purity of the precursor. ２ When Y is blended, the tin compound RSnX ２ It was found that Y may be contained in a trace amount or in a compounded amount. ２ It has been found that Y itself is also useful as a precursor.

[0072] The preferred structure of the substituent Y is the same as that described for the preferred substituent X, but a combination with a specific substituent X may be effective, as shown below.

[0073] The tin compound (B1) is formed of two hydrolyzable groups X and one hydrolyzable group Y, which can undergo reactions such as hydrolysis, and therefore hydrolysis can proceed at unequal rates. Furthermore, by controlling the hydrolysis method, it is possible to preferentially react only specific substituents X and / or Y. Furthermore, the following four examples can be given as preferred combinations of substituents X and Y: 1) The hydrolyzable groups X and Y are NR' and NR', respectively. Y 2 (wherein X's substituent NR'2 and Y's substituent NR' Y 2) The hydrolyzable groups X and Y are OR' and OR', respectively. Y (wherein X's substituent OR' and Y's substituent OR' Y are different chemical formulas) 3) Substituents X and Y are such that X is a substituent NR'2 and Y is a substituent OR' Y 4) When the substituents X and Y are: X is a substituent OR' and Y is a substituent NR' Y If it is 2

[0074] The tin compound of 1) above has a very high hydrolysis reaction rate and the difference in reaction rate between X and Y is small, so that X is NR'2 and Y is NR' Y2 structure is preferred. From the viewpoint of the hydrolysis reaction rate, a particularly preferred structure is one in which R' is a small alkyl group, such as a methyl group or an ethyl group. Furthermore, as shown in the case where X is NR'2 and Y is N(R')(CHNR'2), it is preferable that the R' in one of the substituents on N is the same as the R' contained in X, in order to adjust the difference in reaction rate between X and Y upon hydrolysis. In addition, the N(R')(CH2NR'2) structure is preferred because after separating from the tin atom by hydrolysis, further hydrolysis occurs and the compound decomposes into small molecules that are easy to remove. Specific structures corresponding to this tin compound include, for example, the structures shown below. RSn(NR')2(N(R')CH2NR'2)

[0075] Note that iPrSn(NMe2)2(NMeCH2NMe2) is as follows: 119 Sn-NMR spectrum, 1 It has a chemical shift in H-NMR and can be identified and quantified. 119 Sn-NMR (223.8 MHz; C6D6): δ -82ppm. 1 H-NMR (600 MHz; C6D6): δ 3.37 (s, 2H, CH2), 2.89 (s, 3H, Sn-NMe), 2.86 (s, 12H, Sn-(NMe2)2), 2.15 (s, 6H, NMe2), 1.68 (m, 1H, iPr), 1.33 (s, 6H, iPr).

[0076]

[0077] It should be noted that X is a dialkylamino group (NR'2) (where R' ２ is selected from a methyl group, a primary alkyl group, or a secondary alkyl group), the mechanism of generation of the aforementioned compound RSn(NR')2 (N(R')CH2NR'2) is not clear, but structurally it is thought to be a nitrogen radical (NR') generated by elimination of one of the three dialkylamino groups possessed by the tin compound (A1). ２) inserted into the C-H bond next to the nitrogen atom of another nearby compound (A1). Specifically, as shown in the examples, this compound can be produced by decomposing the tin compound (A1) by heating or light. Furthermore, the above-mentioned compound RSn(NR')2(N(R')CH2NR'2) represents a case where R' is a methyl group, but it can also be used in cases where R' is a primary alkyl group such as an ethyl group (where R' is a CH ２ R １ ), that is, compound (A1) is RSnN(CH ２ R １ ) ３ When the compound (A4) is represented by RSn[N(CH ２ R １ ) ２ ] ２ [N(CH ２ R １ ) CHR １ N (CH ２ R １ ) ２ In addition, when R' is a secondary alkyl group such as an isopropyl group (where R' is represented by RCHR ２ R ３ That is, the compound (A1) is RSn[N(CHR ２ R ３ ) ２ ] ３ When the compound (A4) is represented by RSn[N(CHR ２ R ３ ) ２ ] ２ [N(CHR ２ R ３ )CR ２ R ３ N (CHR ２ R ３ ) ２ ] is expressed as

[0078] The tin compound of 2) is highly stable and has a lower hydrolysis reaction rate than 1), and the difference in reaction rate between X and Y is small. Therefore, the hydrolyzable groups X and Y are preferably OR' and OR', respectively. Y It is particularly preferable that OR', OR' Yare each a secondary alkoxy group (such as an isopropoxy group or a 4-methyl-2-pentanoxy group) or a tertiary alkoxy group (such as a t-butyl group or a t-amyl group) from the viewpoint of the stability of the tin compound. Y A combination of secondary and tertiary alkyl groups is more preferred because it produces an appropriate difference in hydrolysis rate.

[0079] The tin compound of the above 3) is preferably selected from the group consisting of X being a substituent NR'2 and Y being a substituent OR', from the viewpoint that the reaction rate of hydrolysis is high and the difference in reaction rate between X and Y is large. Y From the viewpoint of improving the hydrolysis property of NR'2, it is preferable that R' is a small alkyl group such as a methyl group or an ethyl group. Y is preferably a secondary alkoxy group (such as an isopropoxy group or a 4-methyl-2-pentanoxy group) or a tertiary alkoxy group (such as a t-butyl group or a t-amyl group) from the viewpoint of the stability of the tin compound. In addition, by combining these preferred structures of X and Y, the difference in reaction rate between X and Y can sometimes be widened.

[0080] The tin compound of 4) is highly stable and has a lower hydrolysis reaction rate than 1), and the difference in reaction rate between X and Y is large. From this viewpoint, X is a substituent OR' and Y is a substituent NR'. Y From the viewpoint of the stability of the tin compound, it is preferable that OR' is a secondary alkoxy group (e.g., isopropoxy group, 4-methyl-2-pentanoxy group) or a tertiary alkoxy group (e.g., t-butyl group, t-amyl group). Y In order to improve the hydrolysis property of 2, R' Y In addition, by combining these preferred structures of X and Y, the difference in reaction rate between X and Y can be increased in some cases.

[0081] [Monoalkyltin Composition Containing Tin Compounds (A1) and (B1)] While RSnX and RSnXY can each be hydrolyzed individually to form a tin hydrolyzate, it is preferable to use a mixture containing tin compound (A1) and tin compound (B1), particularly to control the crystallinity of the resulting tin hydrolyzate without reducing its purity. That is, tin compound (A1) and tin compound (B1) have the same organic group R, and the organic group R remaining in the tin hydrolyzate after hydrolysis is essentially equivalent. This is important because it is different from the impurities (e.g., RSnX (A2), SnX (A3)) contained in monoalkyltin compounds with structures different from tin compound (B1). That is, the effects of the present invention tend to be more effectively achieved when the tin compound contains only one type of organic group R with a single chemical structure. A composition containing tin compounds (A1) and (B1) is referred to as a monoalkyltin composition (A1B1).

[0082] The specific composition of the monoalkyltin composition (A1B1) containing tin compounds (A1) and (B1) corresponds to the composition of the tin compounds (A1) and (B1) in the tin hydrolyzate. The composition of the tin compounds (A1) and (B1) in the monoalkyltin composition (A1B1) is not particularly limited. However, from the perspective of obtaining a high-purity tin hydrolyzate, it is preferable that the monoalkyltin composition (A1B1) contains a highly pure tin compound (A1) as the main component and further contains a tin compound (B1). In other words, this composition allows for both the purity and crystallinity of the tin hydrolyzate to be controlled. In particular, the content (purity) of the tin compound (A1) in the monoalkyltin composition (A1B1) is preferably 50 to 99.99 mol%, with a lower limit of 55 mol% or more being more preferred, even more preferably 60 mol% or more, particularly preferably 65 mol% or more, and especially preferably 70 mol% or more. The upper limit is more preferably 99 mol% or less, even more preferably 97 mol% or less, particularly preferably 95 mol% or less, and especially preferably 90 mol% or less. On the other hand, the content (purity) of the tin compound (B1) in the monoalkyltin composition (A1B1) is preferably 0.01 mol% or more and less than 50 mol%, and the lower limit is more preferably 0.1 mol% or more, even more preferably 0.5 mol% or more, particularly preferably 1 mol% or more, especially preferably 3 mol% or more, and especially more preferably 5 mol% or more. The upper limit is more preferably 30 mol% or less, even more preferably 25 mol% or less, particularly preferably 20 mol% or less, and especially preferably 15 mol% or less.

[0083] Furthermore, from the viewpoint of further reducing crystallinity and obtaining a tin hydrolyzate with even higher solubility, it is preferable to use a monoalkyltin composition containing a tin compound (B1) as a main component and further containing a tin compound (A1). In particular, the content (purity) of the tin compound (B1) in the monoalkyltin composition (A1B1) is preferably 50 to 99.99 mol%, with the lower limit being more preferably 55 mol% or more, even more preferably 60 mol% or more, particularly preferably 65 mol% or more, and especially preferably 70 mol% or more. The upper limit is more preferably 99 mol% or less, even more preferably 97 mol% or less, particularly preferably 95 mol% or less, and especially preferably 90 mol% or less. On the other hand, the content (purity) of the tin compound (A1) in the monoalkyltin composition (A1B1) is preferably 0.01 mol% or more and less than 50 mol%, with the lower limit being more preferably 0.1 mol% or more, even more preferably 0.5 mol% or more, particularly preferably 1 mol% or more, especially preferably 3 mol% or more, and especially more preferably 5 mol% or more. The upper limit is more preferably 30 mol% or less, even more preferably 25 mol% or less, particularly preferably 20 mol% or less, and especially preferably 15 mol% or less.

[0084] Furthermore, the total content of the tin compounds (A1) and (B1) in the monoalkyltin composition (A1B1) is preferably 80 mol% or more, more preferably 85 mol% or more, and even more preferably 90 mol% or more. The upper limit is 100 mol%. When the total content of the tin compounds (A1) and (B1) is sufficiently high, a tin hydrolyzate with high purity can be obtained.

[0085] <Impurities> [Tin compounds as impurities] The monoalkyltin composition (A1B1) according to one embodiment of the present invention may contain impurities. The tin compounds as impurities other than the above tin compounds (A1) and (B1) are not particularly limited, but typical examples of tin compounds as impurities include the following tin compounds (A2) and (A3). Tin compounds (A2) and (A3) are difficult to separate because they have similar structures and boiling points to tin compound (A1), making separation by distillation difficult, and they are generated by decomposition of tin compound (A1) during reaction, heating, etc. R2SnX2 (A2) SnX4 (A3)

[0086] In particular, when the boiling points of the tin compound (A1) and the tin compound (A2) or (A3) are close to each other, separation by distillation is often difficult, making it important to suppress this during the reaction and post-treatment. In cases where the tin compounds (A2) and (A3), which are impurities with similar boiling points, are contained, it is preferable to suppress the content of the tin compounds (A2) and (A3) after the reaction. The amount of the tin compounds (A2) and (A3) contained in the synthesized tin compound (crude product) after the reaction is preferably 3 mol% or less, more preferably 2 mol% or less, even more preferably 1 mol% or less, particularly preferably 0.5 mol% or less, especially preferably 0.3 mol% or less, and even more preferably 0.1 mol% or less, 0.05 mol% or less, or 0.03 mol% or less.

[0087] (Boiling Point of Impurities) Here, the boiling point refers to the boiling point when compared under the same pressure, not limited to normal pressure, particularly at the pressure when distillation is carried out. When the boiling point difference is close, it means that the difference in boiling point between the tin compounds (A1) and (A2) is usually 50°C or less, preferably 30°C or less, more preferably 10°C or less, and even more preferably 5°C or less. The lower limit is 0°C. Furthermore, when the molecular weights of R and X are close, the difference in boiling point is close or the intermolecular interaction is strong, making separation often difficult. When the molecular weight difference between R and X is close, it means that the difference is usually 30 or less, preferably 20 or less, more preferably 10 or less, and even more preferably 5 or less. The lower limit is 0.

[0088] As an example, the difference in molecular weight between iPrSn(NMe) (A1-1) and iPrSn(NMe) (A2-1) is small (294 g / mol and 293 g / mol, respectively). The difference is only 1 g / mol. Additionally, the polarity of the isopropyl group and the dimethylamino group are very similar, so the difference in boiling point between the tin compounds (A1-1) and (A2-1) is extremely small. Measurements of the boiling points of these compounds revealed that the difference between the two boiling points was within 2°C in the pressure range of 0.7 to 10 torr. In other words, distillation with high separation capability is required to obtain high-purity tin compound (A1-1).

[0089] Tin compound (A1) and its raw material tin compound (E1) (hereinafter sometimes referred to as the "raw material tin compound") can suffer from decomposition due to side reactions during the reaction and in subsequent post-treatment processes. For example, a disproportionation reaction between tin compounds (A1) and (E1) as shown in the following formula may occur, and this reaction can be accelerated or suppressed depending on various reaction conditions. Light-induced decomposition reactions can also occur, or the decomposition reaction can be accelerated by light and heat. Additionally, the presence of trace amounts of air, moisture, etc. can also promote decomposition.

[0090] (Decomposition of tin compounds)

[0091] It may also contain a divalent tin compound, SnX2 (A8). When the tin compound (A1) is RSn(NR2)3, the following tin compound (A8-1) may be mentioned: Sn(NR'2)2 (A8-1)

[0092] From the viewpoint of obtaining a high-purity resist material, the content of the tin compound A8 is preferably 1.0 mol % or less, calculated as tin atoms, relative to the synthetic tin compound, more preferably 0.5 mol % or less, even more preferably 0.1 mol % or less, and particularly preferably 0.01 mol % or less. The lower limit is 0 mol %.

[0093] Furthermore, depending on the raw materials and manufacturing method used, impurities such as R3SnX and R4Sn, which are tin compounds with many hydrocarbon groups, may also be mixed in as impurities.

[0094] In one embodiment of the present invention, the compound can be obtained by using two or more types of monoalkyltin compounds and / or by conventional hydrolysis of a monoalkyltin compound containing two or more types of organic groups R in one molecule as a raw material.

[0095] (Mixture of Multiple Types of Organic Groups R) The tin hydrolyzate contains an organic group R, and the organic group R may have multiple types. For example, two different substituents R may be present as the substituents that occupy a major proportion of the substituents R. A and R B (The most common substituent R is R A The second most common substituent is R B The substituent R A and R B The organic group R is preferably a hydrocarbon group. A and R B The structure of R is selected from the above range of R, A and R B There are no particular limitations on the structure of the primary hydrocarbon group R 1 , a secondary hydrocarbon group R 2 , a tertiary hydrocarbon group R 3 In selecting the range of R A and R B It is preferable that the structures of "R" and "R" are selected from different ranges. A : Primary hydrocarbon group / R B : tertiary hydrocarbon group R 3 "," "R A : Secondary hydrocarbon group / R B : tertiary hydrocarbon group R 3 " is preferred, and in order to balance sensitivity and hydrophobicity, "R A : Secondary hydrocarbon group / R B : tertiary hydrocarbon group R 3 " is particularly preferred. A : Secondary hydrocarbon group / R B : tertiary hydrocarbon group R 3" is particularly preferred in terms of the balance of performance as a resist material.

[0096] (Cyclic Hydrocarbon Group) Regarding the hydrocarbon group, the cyclic hydrocarbon group R c When the compound contains R, the reactivity during exposure is improved due to the strain of the cyclic skeleton, which may be preferable from the viewpoint of resist sensitivity. c Examples of the cyclic skeleton contained in the hydrocarbon group include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, etc. Among these, those having an alkyl group such as a methyl group at the 1-position (carbon bonded to Sn) may be preferred because they become tertiary hydrocarbon groups, and for example, 1-methyl-cyclopropyl, 1-methyl-cyclobutyl, 1-methyl-cyclopentyl, 1-methyl-cyclohexyl, 1-methyl-cycloheptyl groups, etc. are preferred. c The proportion of is not particularly limited, but the upper limit is preferably 50 mol% or less, more preferably 40 mol% or less, even more preferably 35 mol% or less, and particularly preferably 30 mol% or less. The lower limit is preferably 1 mol% or more, more preferably 5 mol% or more, even more preferably 10 mol% or more, and particularly preferably 15 mol% or more.

[0097] (Hydrocarbon group having an unsaturated bond) Regarding the hydrocarbon group, the hydrocarbon group R u When the unsaturated bond is contained in the hydrocarbon group R, the unsaturated bond reacts or polymerizes during exposure, causing a change in structure, which may be preferable from the viewpoint of resist sensitivity. uExamples of skeletons having an unsaturated bond contained in include alkenes, alkynes, dienes, trienes, benzenes, etc., and alkenes are preferred from the viewpoint of reactivity and stability, and among these, terminal alkenes are preferred from the viewpoint of reactivity. Specific preferred examples include vinyl groups, 1-propenyl groups, allyl groups, 3-butenyl groups, 4-pentenyl groups, etc., and from the viewpoint of resist sensitivity, vinyl groups, 1-propenyl groups, and allyl groups in which the alkene is close to the Sn atom are preferred, and from the viewpoint of stability, it is preferred that the unsaturated bond is two or more carbon atoms away from the Sn atom. In view of the balance between these, allyl groups, 3-butenyl groups, etc. are preferred. The cyclic hydrocarbon group R c The proportion of is not particularly limited, but the upper limit is preferably 50 mol% or less, more preferably 40 mol% or less, even more preferably 35 mol% or less, and particularly preferably 30 mol% or less. The lower limit is preferably 1 mol% or more, more preferably 5 mol% or more, even more preferably 10 mol% or more, and particularly preferably 15 mol% or more.

[0098] (Preferred R A and R B Composition ratio of) Preferred R A and R B The composition ratio of the most abundant hydrocarbon group is R A The second most common hydrocarbon group is R B In this case, R A The content of the hydrocarbon group R is preferably 50 mol % or more, more preferably 60 mol % or more, and even more preferably 70 mol % or more of the substituents constituting the hydrocarbon group. The upper limit is preferably 99 mol % or less, more preferably 95 mol % or less, and even more preferably 90 mol % or less. The hydrocarbon group R that occupies the majority of the hydrocarbon group. A is in the above range, R A The crystal formation during hydrolysis can be appropriately controlled to give a tin compound having suitable crystallinity without impairing the performance of the resist material. BThe content of R is preferably 50 mol% or less, more preferably 40 mol% or less, even more preferably 35 mol% or less, and particularly preferably 30 mol% or less. The lower limit is preferably 1 mol% or more, more preferably 5 mol% or more, even more preferably 10 mol% or more, and particularly preferably 15 mol% or more. B When the composition of is within the above range, R A Without compromising the performance of R B In some cases, it may be possible to give the above characteristics or obtain a tin compound with appropriate crystallinity.

[0099] R A The secondary hydrocarbon group R 2 is preferable, and among these, an isopropyl group is preferable. B As the tertiary hydrocarbon group R 3 , a cyclic hydrocarbon group R c , a hydrocarbon group R having an unsaturated bond u and the tertiary hydrocarbon group R 3 Among these, a t-butyl group is preferred. c Among these, a methylcyclopentyl group is preferred. u Among these, a butenyl group is preferred.

[0100] <Method for producing tin compound (A1)> The method for producing the tin compound (A1) is not particularly limited, and the tin compound (A1) can be produced by a conventionally known method. Specifically, examples of methods for producing a tin compound containing the tin compound (A1) as a main component for the purpose of obtaining the tin compound (A1) include the following production methods.

[0101] (Production Method 1) One example of a method for producing the tin compound (A1) is a method for synthesizing a synthetic tin compound by reacting a raw material tin compound (E1) with a reactant ((M1) or (M2)) in an organic solvent (S1) under specific conditions, with the aim of obtaining the tin compound (A1). As will be described in detail below, a typical reaction scheme for this production method is as follows: RSnY E3(E1)+3MX(M1)→RSnX3(A1)+3MY E

[0102] In the manufacturing method 1, the raw material is a tin compound RSnY E This method is advantageous in that it is possible to increase the purity of RSnX3 (A1) by purifying 3, thereby obtaining high-purity RSnX3 (A1). In addition, since a tin compound into which an organic group R has been previously introduced is used as a raw material, it is possible to reduce impurities such as tin compounds A2, A3, and A4, which are impurities, compared to other methods, and to reduce impurities that are difficult to separate by distillation.

[0103] The material components used in the method for producing the tin compound (A1) will be described below.

[0104] [Raw material tin compound (E1)] The raw material tin compound (E1) is represented by the following formula: RSnY E 3 ... (E1) (In general formula (E1), R is an organic group having 1 to 30 carbon atoms. Examples of such organic groups include halogenated hydrocarbon groups, hydrocarbon groups containing hetero atoms such as oxygen atoms and nitrogen atoms, and hydrocarbon groups. Y E is selected from a halogen atom, OR', and NR'2. R' may be the same or different and is an organic group having 1 to 10 carbon atoms which may be substituted with a halogen. When there are multiple R's in a molecule, they may have different structures and may be bonded to each other to form a cyclic structure.

[0105] Organic group Y in the reaction formula E is an organic group that can be substituted by reaction with the reactant (M1), and the structure thereof is not particularly limited, but preferred examples thereof are organic groups selected from a halogen atom, OR', and NR'2, with halogen atoms being particularly preferred due to their high reactivity. Among these, Cl atoms are preferred because they have a good balance between stability and reactivity, are easy to purify by distillation or the like, and allow for the preparation of a raw material tin compound (E1) with a higher purity, and monoalkyltin chlorides are the most preferred.

[0106] Raw material tin compound RSnY E The purity of 3 can be increased by refining, and high-purity RSnY can be used as a raw material. EIt is preferable to use 3 because the amount of remaining impurities is small and a high-purity tin compound (A1) is increased. Specifically, the tin atom content is usually 95 mol% or more, preferably 97 mol% or more, more preferably 99 mol% or more, even more preferably 99.5 mol% or more, and particularly preferably 99.9 mol% or more. The upper limit is 100 mol%.

[0107] On the other hand, the impurities of tin compounds and moisture may contribute to stabilization, such as preventing crystallization of the target product, or may affect the reaction for synthesizing the tin compound (A1), and therefore it may be preferable that the impurity tin compounds are contained in an amount of 0.1 mol% or more, more preferably 0.2 mol% or more, and even more preferably 0.3 mol% or more. E 2. R3SnY E , R4Sn are each preferably 3 mol % or less, more preferably 2 mol % or less, even more preferably 1 mol % or less, and particularly preferably 0.1 mol % or less, calculated as tin atoms. On the other hand, from the viewpoint of contributing to stabilization, such as preventing crystallization of the target product, R2SnY E 2. R3SnY E , R4Sn may preferably be contained in an amount of 0.01 mol % or more, more preferably 0.1 mol % or more.

[0108] [Reactant (M1)] The reactant (M1) is a raw material tin compound (E1) (RSnY E 3) Organic group Y E The reactant (M1) is capable of a substitution reaction with MX, thereby producing the target tin compound (A1) (RSnX3). Preferred structures of the reactant (M1) include MX, MX2, MX3, etc. For example, when the reactant (M1) is MX, the theoretical reaction formula is as follows: RSnY E 3(E1)+3MX(M1)→RSnX3(A1)

[0109] In the reaction formula, M represents a metal atom of Group 1, Group 2, Group 12, or Group 13. When M is Group 1, it may be expressed as "MX", when it is Group 2 or Group 12, it may be expressed as "MX2", and when it is Group 13, it may be expressed as "MX3", and multiple Xs in the molecule may be different. Furthermore, X is as described in the above section. Specifically, when X is OR', examples include LiOR', NaOR', KOR', MgOR'2, and ZnOR'2, and from the viewpoint of high reactivity, LiOR', NaOR', and KOR' are preferred. When X is NR'2, examples include LiNR'2, NaNR'2, KNR'2, Mg(NR'2)2, Zn(NR'2)2, etc., of which LiNR'2, NaNR'2, and KNR'2 are preferred from the viewpoint of high reactivity, and Mg(NR'2)2 and Zn(NR'2)2 are preferred from the viewpoint of stability, and of these, LiNR'2 (lithium amides: lithium dimethylamide, lithium diethylamide, etc.) is most preferred from the viewpoint of ease of preparation of a highly pure reagent.

[0110] [Reactant (M2)] The reactant (M2) is a compound selected from the reactant (M1) or a compound represented by the chemical formula HX. H is a hydrogen atom, and X has the same meaning as that contained in the tin compound (A1). Examples of compounds corresponding to HX include HOR' (methanol, ethanol, t-butanol, 4-methyl-2-pentanol, etc.) and HNR'2 (dimethylamine, diethylamine, morpholine, etc.). Among the reactants (M2), from the viewpoint of reactivity, compounds selected from the reactant (M1) are preferred because of their high reactivity. From the viewpoint of preventing metal contamination after the reaction, compounds corresponding to HX, i.e., HOR' (methanol, ethanol, t-butanol, 4-methyl-2-pentanol, etc.) and HNR'2 (dimethylamine, diethylamine, morpholine, etc.) are preferred, and the raw material tin compound (E1) (RSnY E 3) Y E When is a highly reactive NR'2, the use of a compound corresponding to HX may give a high purity product without metal contamination.

[0111] (Amount of reactants (M1) and (M2)) In terms of molar equivalents relative to the starting tin compound (E1), the lower limit is preferably 3.00 eq or more, more preferably 3.03 eq or more, and most preferably 3.06 eq or more. The upper limit is preferably 10.00 eq or less, more preferably 8.00 eq or less, and even more preferably 7.00 eq or less. In some cases, a plurality of reactants (M1) and (M2) may be used in combination, and in such cases, it is preferable that the total molar equivalents of the reactants falls within this range.

[0112] (Method for Preparing Reactant (M1)) With regard to the temperature in the step of preparing reactant (M1), the lower limit temperature is preferably about −78° C. or higher, more preferably about −40° C. or higher, even more preferably about −20° C. or higher, particularly preferably about −10° C. or higher, and especially preferably −5° C. or higher. The upper limit temperature is preferably about 40° C. or lower, more preferably about 20° C. or lower, and even more preferably 15° C. or lower. In particular, when reactant (M1) is lithium amide, it must be prepared from an amine and an alkyllithium, and if the temperature is too high, the amine tends to volatilize or the decomposition of the alkylamide tends to be accelerated. Furthermore, if the temperature is too low, the solubility of dimethylamide in the solvent tends to decrease or the viscosity increases, making stirring difficult.

[0113] The reaction time after dropwise addition during preparation of the reactant (M1) is preferably 0.5 hours (hereinafter, "hours" may be referred to as "h") or more as a lower limit, more preferably 1 hour or more, and even more preferably 2 hours or more. The upper limit is preferably 48 hours or less, more preferably 30 hours or less, and even more preferably 20 hours or less. If the reaction time is too short, the reactant (M1) may not be produced with sufficient purity, or in the case of a slurry, the reactant (M1) may be produced inhomogeneously due to insufficient mixing. If the reaction time is too long, the reactant (M1) may decompose, resulting in the generation of by-products or a decrease in the number of equivalents.

[0114] Furthermore, it is preferable to continue stirring the reactant (M1) after its preparation and use the reactant (M1) in this reaction within 3 to 48 hours after its preparation, in order to maintain the purity of the reactant (M1) and to control the water content in the reactant (M1).

[0115] (Method for Preparing Reactant (M2)) Reactant (M2) represents a compound selected from the reactants (M1) or a compound represented by the chemical formula HX. The method for preparing reactant (M1) is as described above and will be described for a compound represented by the chemical formula HX. Commercially available compounds of the chemical formula HX may be used as is, but to avoid contamination with impurities, moisture, or metals, it is preferable to use compounds that have been purified by distillation, adsorption, column chromatography, or the like. Alternatively, products that have been purified to semiconductor grade (EL grade) or dehydrated grade may be commercially available. The specific purity is preferably 95% or more by mass, more preferably 98% or more, even more preferably 99% or more, particularly preferably 99.9% or more, and especially preferably 99.99% or more. The upper limit is 100%. Preferred organic solvents for preparation are those shown in the organic solvent (S1) below. Specifically, the amount of metal contamination is preferably 100 ppm or less by mass of each metal element, more preferably 10 ppm or less, even more preferably 1 ppm or less, particularly preferably 100 ppb or less, and especially preferably 10 ppb or less. The lower limit is 0 ppb.

[0116] [Organic Solvent (S1)] In this production method, a raw material tin compound (E1), a reactant ((M1) or (M2)), and an organic solvent (S1) are used. The organic solvent (S1) is not particularly limited, but examples thereof include hydrocarbons (hexane, cyclohexane, heptane, decane, decalin, etc.), aromatics (benzene, toluene, xylene, anisole, etc.), ethers (THF (tetrahydrofuran), diethyl ether, TBME (t-butyl methyl ether), dibutyl ether, 3-methyl THF, THP (tetrahydropyran), 3-methyl THP, etc.), ketones (acetone, MEK (methyl ethyl ketone), MIBK (methyl isobutyl ketone), etc.), amides (DMF (NN dimethylformamide), DMAC (NN dimethylacetamide), etc.), esters (ethyl acetate, butyl acetate, etc.), and alcohols (methanol, ethanol, isopropanol, butanol, 4-methyl-2-pentanol, etc.). Preferred are aromatic, hydrocarbon, and ether solvents that do not readily react with the reactants. These solvents can be used alone or in combination of two or more. It is preferable that the solvent itself does not contribute to the formation of metal contaminants.

[0117] Particularly preferred are hydrocarbons and aromatic solvents, which have low solubility in inorganic salts and allow for easy removal of by-products such as inorganic salts by filtration or centrifugation after the reaction. Among these, toluene and hexane are currently the most preferred solvents because they allow for easy removal of the product under vacuum at low temperature after the reaction. On the other hand, ethers are preferred solvents for smoothly progressing the reaction due to their high solubility in organometallic reactants such as lithium dimethylamide. In other words, combining multiple solvents, such as hydrocarbons, aromatics, and ethers, can sometimes combine the advantages of these solvents. Furthermore, when HOR' (e.g., methanol, ethanol, t-butanol, 4-methyl-2-pentanol) or HNR'2 (e.g., dimethylamine, diethylamine, morpholine) is used as the reactant (M2), the reactant (M2) may also function as a solvent.

[0118] (Production Method 2) As an example, it is synthesized from a raw material tin compound SnX4 and a reactant RM or RMZ containing R. SnX4 + RM → RSnX3 + MX SnX4 + RMZ → RSnX3 + MXZ E In the above reaction formula, M represents a metal atom of Group 1, Group 2, Group 12, or Group 13, or a hydrogen atom. When M is a Group 1 or a hydrogen atom, it is expressed as "RM", and when M is a Group 2 or Group 12, it is expressed as "RMZ". E ", and for the 13th family, "RMZ E 2", and multiple Xs in the molecule may be different. Z E represents a halogen atom or R. E may be different. X is as described above. Specifically, when X is OR', ROH, RLi, RNa, RK, RMgZ E , RZnZ E Among these, RLi is preferred from the viewpoint of high reactivity, and RMgZ is preferred from the viewpoint of reaction selectivity in monoalkylation and low basicity, which can prevent decomposition of the target compound. E , RZnZ E Among these, RMgZ is most preferable. Furthermore, ROH is preferable from the viewpoint of preventing metal contamination.

[0119] Due to the reaction format, this method suffers from the problem of contamination with by-products containing multiple organic groups R. In relation to this point, the structure of RSnX3 (A1) for which this method is effective is a structure in which the organic group R is a tertiary alkyl group (e.g., t-butyl, t-amyl, 1-methyl-cyclopentyl, 1-methyl-cyclohexyl). In this case, the reactivity of the reactant RM is easily controlled with a bulky tertiary alkyl group, and multiple bulky tertiary alkyl groups are unlikely to be introduced onto the Sn atom, so there is a tendency to selectively obtain the target product to which one alkyl group is attached in good yield. In addition, the boiling points of by-products containing multiple organic groups R are different from those of the target product, making them easy to separate by distillation, which is another factor that makes this method effective.

[0120] (Production Method 3) As an example, a step a of producing MSnX3 from a reactant containing SnX2, a monoalkyltin compound as raw materials, and MX, and a step b of reacting the resulting MSnX3 with an alkylating agent RZ F SnX + MX → MSnX 3 (Process α) MSnX3+RZ F → RSnX 3 (Process β)

[0121] In the reaction formula, M represents a metal atom of Group 1, Group 2, Group 12, or Group 13. When M is Group 1, it may be represented as "MX", when it is Group 2 or Group 12, it may be represented as "MX2", and when it is Group 13, it may be represented as "MX3". Multiple Xs in a molecule may be different. X is as described in the above section. Specifically, when X is OR', examples include LiOR', NaOR', KOR', MgOR'2, and ZnOR'2, and from the viewpoint of high reactivity, LiOR', NaOR', and KOR' are preferred. When X is NR'2, examples include LiNR'2, NaNR'2, KNR'2, Mg(NR'2)2, and Zn(NR'2)2, and from the viewpoint of high reactivity, LiNR'2, NaNR'2, and KNR'2 are preferred. Among them, LiNR'2 is most preferred from the viewpoint of ease of preparation of a high-purity reagent. Alkylating Agent RZ F In this case, Z F is a halogen atom (F, Cl, Br, I), and among these, Br and I are preferred from the viewpoint of reactivity.

[0122] In this method, the organic group R is replaced with an alkyl halide RZ, which is easy to synthesize and obtain. F This method has the advantage that it can be introduced from the starting point. In this respect, it is effective when the organic group R is unstable and would cause decomposition or side reactions if applied to Production Methods 1 and 2. Specifically, it may be effective when the organic group R has a heteroatom, an unsaturated bond, or an aromatic ring.

[0123] (Distillation Purification) The synthesized tin compound (A1) (crude product) may be further purified by distillation. The crude product is distilled and purified and referred to as a "purified tin compound." The higher the proportion of tin compound (A1) in the purified tin compound, the better the resist performance. Therefore, the purity of the tin compound (A1) is preferably 96 mol%, more preferably 97 mol%, even more preferably 98 mol% or more, particularly preferably 99% mol% or more, particularly preferably 99.2 mol% or more, particularly more preferably 99.5 mol% or more, even more preferably 99.8 mol% or more, and most preferably 99.9 mol% or more. On the other hand, if the purity of the triaminotin compound is too high, the disproportionation reaction of the organic group R of the tin compound (A1) may cause decomposition or instability during storage or use. In this case, the purity is preferably 100.0 mol% or less, more preferably 99.9 mol% or less.

[0124] The inorganic impurities in the purified tin compound are preferably low for use as a resist material, specifically, the content of each inorganic impurity element is preferably 10 ppm or less, more preferably 1 ppm or less, even more preferably 0.1 ppm or less, and particularly preferably 0.01 ppm or less.

[0125] If the purified tin compound does not reach a sufficient quality, other purification treatments (filtration, column purification, addition of adsorbents, reactants, etc.) may be carried out before or after distillation.

[0126] <Method for Producing Tin Compound (B1)> The method for producing the tin compound (B1) is not particularly limited, and the compound can be produced by a conventionally known method. A preferred production method is, for example, the following production method similar to "Production Method 1 for Tin Compound (A1)." In the first production method (Production Method 1 for B1), the monoalkyltin compound RSnX3 (A1) is reacted with a reactant (M1Y or M2Y) containing 1 equivalent of Y under specific conditions in an organic solvent (S1) (or solvent-free, if necessary), to obtain the tin compound (B1). Note that the reactants M1Y and M2Y are reactants in which the substituent X in the reactants M1 and M2 described in the production method for the monoalkyltin compound RSnX3 (A1) above is replaced with Y, as shown below.

[0127] In B1 Production Method 1, a typical reaction scheme is as follows: RSnX3 (A1) + MY (M1Y or M2Y) → RSnX2Y (B1) + MX (X is OR', NR'2, C≡CR', Y is OR' Y , NR' Y 2. C≡CR' Y ) selected from

[0128] In the second production method (B1 Production Method 2), a monoalkyltin compound RSnY3 is reacted with a reactant (M1 or M2) containing 2 equivalents of X under specific conditions in an organic solvent (S1) (or without solvent, if necessary), to obtain a tin compound (B1). In B1 Production Method 2, a typical reaction formula is as follows: RSnY 3 +2MX (M1 or M2) →RSnX2Y (B1) +2MY2

[0129] The structure of the monoalkyltin compound RSnX3 (A1) used as a raw material in the reaction scheme of B1 Production Method 1 is not particularly limited, but it is preferable that X is NR'2 because of the high reactivity of the above reaction. The high reactivity makes it possible to selectively react only equivalent amounts of the reactants MY and MY1 as described above, and there is a possibility of obtaining RSnX2Y (B1) with high purity.

[0130] The structure of the monoalkyltin compound RSnY3 used as a raw material in B1 Production Method 2 is not particularly limited, but may be any of the following: Y 2 is preferred from the viewpoint of high reactivity of the above reaction. High reactivity makes it possible to selectively react only the equivalent of MX2 as the reactant, as described above, and there is a possibility of obtaining RSnX2Y (B1) with high purity.

[0131] The raw materials for each manufacturing method are the tin compounds RSnX3 (A1) and RSnY 3 The purity can be increased by refining, and high-purity RSnX3 (A1) and RSnY are available as raw materials. 3 It is preferable to use a tin compound (B1) because the amount of remaining impurities is small and a high-purity tin compound (B1) is increased. Specifically, the tin atom content is usually 95 mol% or more, preferably 97 mol% or more, more preferably 99 mol% or more, even more preferably 99.5 mol% or more, and particularly preferably 99.9 mol% or more. The upper limit is 100 mol%.

[0132] On the other hand, impurities such as tin compounds and moisture may contribute to stabilization, such as preventing crystallization of the target product, or may affect the reaction for synthesizing the tin compound (B1). Therefore, it may be preferable for the impurity tin compounds to be contained in an amount of 0.1 mol% or more, more preferably 0.2 mol% or more, and even more preferably 0.3 mol% or more. Specifically, R2SnX2, R3SnX, and R4Sn are each preferably 3 mol% or less, more preferably 2 mol% or less, even more preferably 1 mol% or less, and particularly preferably 0.1 mol% or less, calculated as tin atoms. On the other hand, from the viewpoint of contributing to stabilization, such as preventing crystallization of the target product, it may be preferable for R2SnX2, R3SnX, and R4Sn to be contained in an amount of 0.01 mol% or more, more preferably 0.1 mol% or more.

[0133] [Reactant (M1Y)] The reactant (M1Y) is a reactant capable of undergoing a substitution reaction with the substituent X of the raw material tin compound RSnX3 (A1) to produce the target tin compound (B1) (RSnX2Y). In particular, a reactant with appropriate reactivity that allows only one equivalent to be selectively reacted is preferred. Examples of the structure of the reactant (M1Y) include MY, MY2, and MY3.

[0134] In the reaction formula, M represents a metal atom of Group 1, Group 2, Group 12, or Group 13. When M is Group 1, it may be expressed as "MY", when it is Group 2 or Group 12, it may be expressed as "MY2", and when it is Group 13, it may be expressed as "MY3", and multiple Ys in a molecule may be different. Y is as described in the above section. Specifically, when Y is OR' Y At the time of LiOR' Y , NaOR' Y , KOR' Y , MgOR' Y 2, ZnOR'2, etc., and from the viewpoint of high reactivity, LiOR', NaOR', and KOR' are preferred. Y At 2, LiNR' Y 2. NaNR' Y 2. KNR' Y 2. Mg(NR' Y 2)2, Zn(NR' Y 2) 2, etc., and from the viewpoint of high reactivity, LiNR' Y 2. NaNR' Y 2. KNR' Y 2 is preferred, and Mg(NR') is preferred from the viewpoint of stability. Y 2)2, Zn(NR' Y 2) 2 is preferred, and among them, LiNR' is preferred because of the ease of preparing a highly pure reagent. Y 2 (lithium amides: lithium dimethylamide, lithium diethylamide, etc.) are most preferred.

[0135] [Reactant (M2Y)] The reactant (M2Y) is a compound selected from the reactants (M1Y) or a compound represented by the chemical formula HY. H is a hydrogen atom, and Y has the same meaning as that included in the tin compound (B1). Examples of compounds corresponding to HY include HOR' Y(methanol, ethanol, t-butanol, 4-methyl-2-pentanol, etc.) and HNR' Y 2 (dimethylamine, diethylamine, morpholine, etc.). Among the reactants (M2Y), from the viewpoint of reactivity, compounds selected from the reactants (M1Y) are preferred because they have high reactivity. From the viewpoint of preventing metal contamination after the reaction, compounds corresponding to HY, i.e., HOR' Y (methanol, ethanol, t-butanol, 4-methyl-2-pentanol, etc.), HNR' Y 2 (dimethylamine, diethylamine, morpholine, etc.) are preferred.

[0136] <Reaction conditions for B1 production method 1> In B1 production method 1, a monoalkyltin compound RSnX3 (A1) is reacted with a reactant (M1Y or M2Y) containing 1 equivalent of Y under specific conditions in an organic solvent (S1) (or without a solvent, if necessary), to obtain a tin compound (B1). The reaction conditions can also be determined by referring to the contents described in "Production method 1 of tin compound (A1)".

[0137] In particular, it is preferable to use an OR' group or an NR'2 group as the X group in the raw material tin compound RSnX3 from the viewpoints of selectivity and reactivity for one-equivalent addition, with NR'2 being preferred from the viewpoint of reactivity. On the other hand, an OR' group may be preferred from the viewpoints of combination with the reactant and selectivity. Furthermore, as the reactant, a reactant having an HY structure may be preferred as it may give a high-purity product without metal contamination, and it is particularly effective when the X group in the raw material tin compound RSnX3 is a highly reactive OR' group or NR'2 group. In particular, among reactants having an HY structure, secondary and tertiary alcohols (e.g., isopropanol, t-butanol, 4-methyl-2-pentanol) are preferred because they highly selectively react with one equivalent due to steric hindrance. Similarly, even when RSnX3 is stored in a mixed state with a reactant having an HY structure, this reaction may occur, and Production Method B1 1 may be carried out.

[0138] The amount of reactant, calculated in molar equivalents, is preferably 0.80 eq or more, more preferably 0.90 eq or more, and most preferably 0.95 eq or more. The upper limit is preferably 2.00 eq or less, more preferably 1.50 eq or less, and even more preferably 1.10 eq or less. In this production method, the selective reaction of one equivalent is controlled by the equivalent amount, which affects the purity of the resulting tin compound (B1). Furthermore, by controlling the equivalent amount and reaction conditions, it is sometimes possible to obtain a monoalkyltin composition (precursor mixture) containing RSnX3 (A1), RSnX3, RSnX2Y (B1), RSnXY2, RSnY3, etc. in a specific composition.

[0139] <Reaction conditions for B1 production method 2> In B1 production method 2, a monoalkyltin compound RSnY3 is reacted with a reactant (M1 or M2) containing 2 equivalents of X under specific conditions in an organic solvent (S1) (or no solvent as necessary), to obtain a tin compound (B1). The reaction conditions can also be determined by referring to the contents described in "Production method 1 of tin compound (A1)".

[0140] In particular, the Y group of the raw material tin compound RSnY3 is OR' Y group or NR' Y The use of two groups is preferred from the viewpoint of selectivity and reactivity of the addition of two equivalents, and from the viewpoint of reactivity, NR' Y On the other hand, from the viewpoint of combination with reactants and selectivity, OR' Y In addition, a reactant having a HX structure is preferred as it can give a high-purity product without metal contamination, and in particular, the Y group of the raw material tin compound RSnY3 is preferably a highly reactive OR' group. Y group or NR' YIt is effective when there are two groups. Among reactants having an HX structure, secondary and tertiary alcohols (isopropanol, t-butanol, 4-methyl-2-pentanol, etc.) are particularly preferred because they highly favor the selective reaction of two equivalents due to steric hindrance. Similarly, this reaction may occur even when RSnY3 is stored in a mixed state with a reactant having an HX structure, making it possible to carry out B1 Production Method 2. The amount of reactant, in molar equivalent terms, is preferably 1.80 eq or more as a lower limit, more preferably 1.90 eq or more, and most preferably 1.95 eq or more as an upper limit. It is preferably 4.00 eq or less, more preferably 2.50 eq or less, and even more preferably 2.10 eq or less. In this production method, the selective reaction of two equivalents is controlled by the equivalent amount, which affects the purity of the resulting tin compound (B1). Furthermore, by controlling the equivalent amounts and reaction conditions, it may be possible to obtain a monoalkyltin composition (precursor mixture) containing RSnX3 (A1), RSnX3, RSnX2Y (B1), RSnXY2, RSnY3, etc. in a specific composition.

[0141] <<Application as a Resist Material>> The tin hydrolyzate (P1) of this embodiment is obtained by hydrolyzing a tin composition containing tin compounds (A1) and (B1) in a specific blend ratio.

[0142] <Method for producing the present tin hydrolyzate> The method for producing the present tin hydrolyzate preferably involves hydrolysis by the following steps: <Step 1> Using tin compounds (A1) and (B1) in a specific blend ratio as a raw material, a tin composition. <Step 2> Contacting the raw material with water and / or water vapor.

[0143] In step 1, a monoalkyltin composition (A1B1) is prepared by mixing tin compounds (A1) and (B1) in a specific ratio. In this step, the precursor mixture is not hydrolyzed and its chemical structure remains unchanged. Therefore, step 1 is preferably performed under an inert gas atmosphere. This monoalkyltin composition must then be used in step 2. The preparation method may involve mixing two or more precursors, or a monoalkyltin composition in which (A1) and (B1) have already been mixed during synthesis, purification, storage, or other processes may be used. In steps 1 and 2, other additives such as solvents are not required. However, particularly when liquid precursors are uniformly prepared and mixed (step 1) and uniformly contact-reacted (mixed) with water or steam (step 2), it is preferable to use 100 parts by mass or more of an organic solvent per 100 parts by mass of the precursors in each step.

[0144] Specifically, it is preferable to prepare a tin composition containing tin compounds (A1) and (B1) in a specific blending ratio under an inert gas atmosphere (Step 1), convert such composition or a blend prepared by blending it with an organic solvent as needed into a gaseous and / or liquid state, and then contact it with water and / or water vapor to hydrolyze the precursor (Step 2). In this case, the organic solvent used in Step 2 is preferably a solvent that does not hydrolyze the precursor, and specifically, an aprotic solvent is preferred, and a dehydrated aprotic solvent is more preferred. The water used in Step 2 is preferably liquid water.

[0145] [Organic Solvent During Hydrolysis] In the present production method, the organic solvent is not particularly limited, but preferred examples include hydrocarbon-based organic solvents (hexane, cyclohexane, heptane, decane, decalin, etc.), aromatic-based organic solvents (benzene, toluene, xylene, anisole, etc.), ether-based organic solvents (THF (tetrahydrofuran), diethyl ether, TBME (t-butyl methyl ether), dibutyl ether, 3-methyl THF, THP (tetrahydropyran), 3-methyl THP, etc.), ketone-based organic solvents (acetone, MEK (methyl ethyl ketone), MIBK (methyl isobutyl ketone), etc.), amide-based organic solvents (DMF (NN dimethylformamide), DMAC (NN dimethylacetamide), etc.), ester-based organic solvents (ethyl acetate, butyl acetate, etc.), halogen-based organic solvents (dichloromethane, chloroform), and alcohol-based organic solvents (methanol, ethanol, isopropanol, butanol, 4-methyl-2-pentanol, etc.). Preferred are combinations of solvents that do not react with the precursor to be used. Specifically, in highly reactive systems in which the precursor structure contains an NR group or the like, aprotic solvents are preferred, and specific examples of aprotic solvents include aromatic, hydrocarbon, ether, and halogen-based solvents. These solvents can be used alone or in combination of two or more. It is preferable that the solvent itself does not contribute to metal contaminants. The solvent used for hydrolysis may affect the crystallinity of the resulting tin hydrolyzate. Using a low-polarity aprotic solvent (especially a hydrocarbon solvent such as hexane) in which the tin hydrolyzate is poorly soluble may reduce the crystallinity and result in a highly soluble tin hydrolyzate, which is preferable. Furthermore, when hydrolysis is performed in a coating solvent and a thin film is formed after coating, the solvent used for hydrolysis may also need to be suitable as a coating solvent. In such cases, the above-mentioned ketone solvents, ester solvents, alcohol solvents, etc., which are suitable as coating solvents in semiconductor processes, may be preferred.

[0146] [Conditions for Hydrolysis] The temperature during hydrolysis is not particularly limited as long as the reaction with water proceeds at the desired rate. However, in the process using the organic solvent and liquid water described above, a temperature between -10°C and 150°C is preferred. Since the rate of hydrolysis is determined by the structure of the hydrolyzable groups X and Y, the appropriate temperature for the hydrolysis depends on the structure of the substituents X and Y. When the substituents X and Y are OR', the lower limit of the temperature during hydrolysis is preferably 0°C or higher, more preferably 30°C or higher, and particularly preferably 40°C or higher. The upper limit is preferably 150°C or lower, and more preferably 140°C or lower. When the substituents X and Y are NR'2, the temperature is preferably -10°C or higher, more preferably 0°C or higher, and the upper limit is preferably 150°C or lower, and particularly preferably 140°C or lower. Furthermore, if the tin hydrolyzate does not precipitate after hydrolysis using an organic solvent, it is preferable to volatilize the organic solvent to precipitate the tin hydrolyzate. The organic solvent can be volatilized by heating at normal pressure, or by heating under reduced pressure. This process of volatilizing the organic solvent may also be carried out during the formation of a thin film containing a tin hydrolyzate, as described below.

[0147] <Method for forming a thin film containing the present tin hydrolysate> The present tin hydrolysate (P1) shown above can be used as a resist material. Regarding its use as a resist material, for example, the method disclosed in JP 2021-21953 A can be used. For use as a resist material, there are two methods for forming a thin film (coating layer, coating film, etc.) containing the present tin hydrolysate on a substrate, for example, the dry method and the wet method described below.

[0148] In the dry method, the raw material for tin hydrolysate, a monoalkyltin compound (precursor), is vaporized under heat or reduced pressure and used as a vapor. The precursor vapor or the precursor deposited on a substrate is reacted with water vapor or other gases to synthesize the tin hydrolysate. By carrying out this method on a substrate, a thin film (coating film) containing the tin hydrolysate can be formed on the substrate. If necessary, the formation of the tin hydrolysate can be accelerated by combining reaction, heating, washing, or other processes before and after this process.

[0149] In the wet method, a raw material containing a monoalkyltin compound (precursor), which is the raw material for the tin hydrolyzate, is reacted with water or the like in solution or solid state to hydrolyze the tin hydrolyzate. The tin hydrolyzate can then be used as a coating solution by dissolving it in an organic solvent or the like. Alternatively, a solution containing the precursor may be first applied to a substrate, and then part or all of the above hydrolysis process may be carried out on the substrate before the tin hydrolyzate is produced.

[0150] In the coating step, the coating can be applied to a substrate by any coating or printing technique, and a thin film (coating film) containing the tin hydrolyzate can be formed on the substrate.

[0151] <Patterning of Thin Films> The thin film obtained by any of the above methods may be stabilized or partially condensed by drying, heating, etc., before irradiation with light. Generally, the thin film (coating film) is thin, e.g., having an average thickness of less than 10 microns, although very thin submicron films, e.g., about 100 nm or less, even 50 nm or less, and particularly 30 nm or less, may be desired for patterning very small features. The resulting thin film (coating film) can be referred to as a "resist" because exposure to light treats the composition so that portions of the composition are resistant to development / etching.

[0152] The thin film (coating film) can be exposed to appropriate radiation, such as extreme ultraviolet, electron beam, or ultraviolet radiation, using a selected pattern or the negative of the pattern to form a latent image with developer-resistant and developer-soluble areas. After exposure to the appropriate radiation and before development, the thin film can be heated or otherwise reacted to differentiate the latent image from non-irradiated areas. The latent image is then contacted with a developer to form a physical image, i.e., a patterned thin film. The patterned thin film can be further heated to stabilize the remaining patterned thin film on the surface. The patterned thin film can be used as a physical mask to perform further processing according to the pattern, such as etching the substrate and / or depositing additional materials. After using the patterned thin film as a resist as desired, the remaining patterned thin film can be removed at an appropriate point in processing, or the patterned thin film can be incorporated into a final structure.

[0153] The conditions for each process are described in more detail below.

[0154] <Preparation and Filtration of Resist Solution> Generally, the resist solution used in the wet method is prepared by thoroughly mixing using an appropriate mixing device suitable for the volume of the material to be formed. Any contaminants or other insoluble components can be removed using appropriate filtration. In some embodiments, the prepared resist solution may be mixed and used. In addition to the tin compound as the main component, various additives may be added to the resist solution.

[0155] <Coating onto a Substrate> The precursor for dry processes and the resist solution for wet processes are selected based on their adhesion to the substrate and subsequent processability. The precursor for dry processes and the resist solution for wet processes are generally applied to the substrate surface. The substrate may include multiple layers on its surface. In some embodiments, the substrate surface may be treated to promote adhesion of the precursor for dry processes and the resist solution for wet processes. The substrate surface may also be cleaned and / or smoothed as needed. Suitable substrate surfaces can include any reasonable material. Some substrates of particular interest (e.g., silicon wafers, silica substrates) contain other inorganic materials, such as ceramic materials, polymeric substrates, organic polymers, composites thereof, and combinations thereof, on and / or within the substrate surface layer. While wafers, such as relatively thin circular structures, can be convenient substrates, any reasonably shaped structure can be used.

[0156] Polymer substrates or substrates having a polymer layer on a non-polymeric structure may be desirable for certain applications due to their low cost and flexibility. Such polymers may be selected based on the relatively low processing temperatures that can be used to process the patterning materials described herein. Such polymers preferably include, for example, polycarbonates, polyimides, polyesters, polyalkenes, copolymers thereof, and mixtures thereof.

[0157] Generally, it is desirable for the substrate to have a flat surface, particularly for high-resolution applications. However, in certain embodiments, the substrate may have substantial topography, and the resist coating is intended to fill or planarize features for certain patterning applications. Such functionality of resist materials is described in U.S. Patent Application Publication No. 2015 / 0253667 (Bristol et al.), entitled "Pre-Patterned Hard Mask for Ultrafast Lithographic Imaging," which is incorporated herein by reference.

[0158] Generally, any suitable coating process can be used to coat the substrate with the precursor (dry method) or the resist solution (wet method). Examples of suitable coating methods include, for example, spin coating, spray coating, dip coating, knife-edge coating, and printing methods (e.g., inkjet printing and screen printing) for wet methods, while dry methods include vapor deposition methods such as physical vapor deposition and chemical vapor deposition. While some of these coating methods form patterns during the coating process, the resolution currently achieved by printing and the like is significantly lower than that achieved by the radiation-based patterning described herein. To provide greater control over the coating process, the coating material can be applied in multiple coating steps. For example, multiple spin coatings can be performed for wet methods, and multiple vapor depositions can be performed for dry methods to achieve the desired final coating thickness. The heat treatment described below can be applied after each coating step or after multiple coating steps.

[0159] When patterning is performed using radiation, spin coating can be a desirable means for achieving a relatively uniform coating of the substrate, although edge effects may exist. In some embodiments, the wafer may be spun at a speed of about 500 to about 10,000 rpm, in further embodiments about 1,000 to about 7,500 rpm, and in additional embodiments about 2,000 to about 6,000 rpm. The rotation speed may be adjusted to achieve the desired coating thickness. Spin coating may be performed for a time period of about 5 seconds to about 5 minutes, and in further embodiments about 15 seconds to about 2 minutes. An initial slow rotation speed (e.g., 50-250 rpm) may be used to perform an initial bulk application of the composition across the entire substrate. To remove any edge bead, a backside rinse, edge bead removal step, or the like, using water or other suitable solvent may be performed. A person of ordinary skill in the art will recognize that additional ranges of spin coating parameters within the explicit ranges above are contemplated and are within the scope of the present disclosure.

[0160] The thickness of a coating film generally tends to depend on the concentration, viscosity, and spin-coating rotation speed of the resist solution for wet processes, and on the deposition pressure for dry processes. For other coating processes, the thickness can also generally be adjusted by selecting coating parameters. In some embodiments, it may be desirable to use a thin coating to facilitate the formation of small and highly modified features in a subsequent patterning process. For example, the coating film after drying can have an average thickness of about 10 μm or less, in other embodiments about 1 μm or less, in further embodiments about 250 nm or less, in additional embodiments about 1 to about 50 nm, in other embodiments about 2 to about 40 nm, and in some embodiments about 3 to about 25 nm. One of ordinary skill in the art will recognize that additional ranges of thickness within the explicit ranges above are contemplated and are within the scope of the present disclosure. The thickness can be evaluated using non-contact methods of X-ray reflectivity and / or ellipsometry based on the optical properties of the film. Generally, the coating film is relatively uniform to facilitate processing. In some embodiments, the coating film thickness varies by no more than ±50% from the average coating thickness, in further embodiments by no more than ±40%, and in additional embodiments by no more than about ±25% relative to the average coating thickness. In some embodiments, such as highly uniform coatings on larger substrates, evaluation of coating uniformity may be evaluated using a 1 cm edge exclusion; that is, coating uniformity is not evaluated within 1 cm of the coating edge. A person of ordinary skill in the art will recognize that additional ranges within the explicit ranges above are contemplated and are within the present disclosure.

[0161] The coating process itself may result in evaporation of some of the solvent, as multiple coating processes form droplets or other forms of coating material with larger surface areas and / or solution migration that stimulates evaporation. Solvent evaporation tends to increase the viscosity of the coating material as the species concentration in the material increases. The goal during the coating process may be to remove enough solvent to allow the active ingredients of the precursor (dry process) and the resist solution (wet process) to react and stabilize them for further processing. That is, solvent may be removed, hydrolyzed tin compounds may form, or condense during the coating process or subsequent heating steps. Typically, the precursor (dry process) and the resist solution (wet process) may be heated prior to radiation exposure to promote densification. In the dried coating film, the precursor (dry process) and the resist solution (wet process) generally form a polymeric metal-oxo / hydroxo network based on oxo-hydroxo ligands to the metal, where the metal also has a molecular solid composed of some hydrocarbon groups or polynuclear metal-oxo / hydroxo species with hydrocarbon groups.

[0162] For wet processes, the solvent removal process may or may not be quantitatively controlled with respect to the specific amount of solvent remaining in the coating material, and empirical evaluation of the properties of the resulting resist solution may generally be performed to select processing conditions that are effective for the patterning process. While heating is not required for successful process application, it may be desirable to heat the coated substrate to accelerate processing and / or increase process reproducibility. In embodiments where heating is applied to remove solvent, the coated substrate with the coating film may be heated to about 45 to about 250°C, and in further embodiments, about 55 to about 225°C. Heating for solvent removal may generally be carried out for at least about 0.1 minutes, in further embodiments, from about 0.5 to about 30 minutes, and in additional embodiments, from about 0.75 to about 10 minutes. Those skilled in the art will recognize that additional ranges of heating temperature and time within the explicit ranges above are contemplated and are within the scope of the present disclosure. As a result of heat treatment and densification, the coating film may exhibit an increase in refractive index and radiation absorption without a significant loss of contrast.

[0163] Patterning by Exposure and Patterned Coating Films Coating films can be finely patterned using radiation. As described above, the composition of the coating film, depending on the composition of the resist solution, can be designed to sufficiently absorb the desired form of radiation. Absorption of radiation generates energy that breaks the bonds between the metal and the hydrocarbon groups, resulting in at least some of the hydrocarbon groups no longer being available to stabilize the material. Radiation degradation products, including hydrocarbon groups or fragments, may or may not diffuse from the film, depending on process variables and the identity of such products. Upon absorption of a sufficient amount of radiation, the exposed coating film condenses, i.e., forms an enhanced metal oxo / hydroxo network, which may include water absorbed from the ambient atmosphere. Radiation can generally be delivered according to a selected pattern. Such a radiation pattern is transferred as a latent image in the coating film, with corresponding irradiated and non-irradiated areas. The irradiated areas tend to chemically alter the components that make up the coating film. As described below, upon development, selective removal of the non-irradiated or irradiated portions of the coating film can form patterns with very sharp edges.

[0164] The radiation may typically be directed to the coated substrate through a mask, or a radiation beam may be controllably scanned across the substrate. Generally, the radiation may comprise electromagnetic radiation, an electron beam (beta radiation), or other suitable radiation. Generally, the electromagnetic radiation may have a desired wavelength or range of wavelengths, such as visible light, ultraviolet light, or X-rays. The achievable resolution for a radiation pattern generally depends on the wavelength of the radiation, with higher resolution patterns generally being achievable with shorter wavelength radiation. Therefore, it may be desirable to use ultraviolet light, X-rays, or an electron beam to achieve particularly high resolution patterns.

[0165] According to International Standard ISO 21348 (2007), incorporated herein by reference, ultraviolet radiation spans the wavelength range from 100 nm to less than 400 nm. A krypton fluoride laser can be used as a 248 nm ultraviolet source. The ultraviolet range can be subdivided in several ways under accepted standards, such as extreme ultraviolet (EUV), which is from 10 nm to less than 121 nm, and far ultraviolet (FUV), which is from 122 nm to less than 200 nm. The 193 nm line from an argon fluoride laser can be used as a radiation source in the FUV range. EUV light is used for lithography at 13.5 nm, and is generated from Xe or Sn plasma sources excited using high-energy lasers or discharge pulses. Soft x-rays can be defined as from 0.1 nm to less than 10 nm.

[0166] The amount of electromagnetic radiation can be characterized by the fluence or dose, which is the integrated radiant flux over the exposure time. Suitable radiation fluences are from about 1 to about 150 mJ / cm. 2 and in further embodiments from about 2 to about 100 mJ / cm 2 , and in further embodiments from about 3 to about 50 mJ / cm 2 A person of ordinary skill in the art will recognize that additional ranges of radiation fluence within the explicit ranges above are contemplated and are within the present disclosure.

[0167] In electron beam lithography, the electron beam typically induces secondary electrons, which typically alter the irradiated material. Resolution can be, at least in part, a function of the range of the secondary electrons within the material, where it is believed that higher resolution generally results from shorter-range secondary electrons. Based on the high resolution achievable by electron lithography using the inorganic coating materials described herein, the range of secondary electrons in inorganic materials is limited. The electron beam can be characterized by the energy of the beam, with suitable energies ranging from about 5 V to about 200 kV, and in further embodiments, from about 7.5 V to about 100 kV. The proximity-corrected beam dose at 30 kV is about 0.1 μC / cm 2~Approx. 5mC / cm 2 , and in a further embodiment, about 0.5 μC / cm 2 ~Approx. 1mC / cm 2 , and in other embodiments, about 1 μC / cm 2 ~Approx. 100μC / cm 2 A person of ordinary skill in the art will be able to calculate corresponding doses at other beam energies based on the teachings herein and will recognize that additional ranges of electron beam characteristics within the explicit ranges above are contemplated and are within the scope of the present disclosure.

[0168] Based on the design of the precursor in dry processes and the resist solution in wet processes, a large contrast in material properties exists between the irradiated and non-irradiated regions of the coating film, which have substantially unchanged hydrocarbon groups. While the contrast in dosage can be improved by a post-exposure heat treatment, in some embodiments, satisfactory results can be obtained without a post-exposure heat treatment. The post-exposure heat treatment appears to anneal the irradiated regions, increasing their condensation without significantly condensing the non-irradiated regions of the coating film due to thermal breakdown of the hydrocarbon group-metal bonds. For embodiments in which a post-exposure heat treatment is used, the post-exposure heat treatment may be carried out at a temperature of from about 45 to about 250°C, from about 50 to about 190°C in additional embodiments, and from about 60 to about 175°C in further embodiments. The post-exposure heat treatment may generally be carried out for at least about 0.1 minute, from about 0.5 to about 30 minutes in further embodiments, and from about 0.75 to about 10 minutes in additional embodiments. A person of ordinary skill in the art will recognize that additional ranges of post-exposure heat temperatures and times within the explicit ranges above are contemplated and are within the scope of the present disclosure. This high contrast in material properties further facilitates the formation of sharp lines in the pattern after development, as described in the following section. As a result, after exposure to radiation, the coating film is patterned with irradiated and non-irradiated areas.

[0169] Development and Patterned Structures: Image development involves contacting the coating film containing the latent image with a developer composition to either remove the non-irradiated portions to form a negative image or remove the irradiated portions to form a positive image. Using the precursors for dry processes and resist solutions for wet processes described herein, effective negative or positive patterning with desired resolution can be achieved using an appropriate developer, typically based on the same coating. In particular, the irradiated areas tend to at least partially condense, enhancing the properties of the components that make up the coating film, making them resistant to dissolution by organic solvents, while the non-irradiated areas tend to remain soluble in organic solvents. The irradiated areas tend to further condense due to the cleavage of hydrocarbon-tin bonds, liberating hydrocarbon groups, enhancing the metal oxide-like properties of the components that make up the coating film. Meanwhile, the non-irradiated material is less soluble in weak bases or aqueous acids due to its hydrophobic nature, lacking the release of hydrocarbon groups. Therefore, for positive patterning, an aqueous base can be used to remove the irradiated material while preserving the non-irradiated material.

[0170] Dry process precursors and wet process resist solutions containing hydrocarbon groups inherently produce relatively hydrophobic materials. Irradiation to break at least some of the organometallic bonds converts the material to a less hydrophobic, i.e., more hydrophilic, material. This change in properties provides a significant contrast between irradiated and non-irradiated areas of the coating film, thereby enabling both positive and negative patterning of the same coating film. Specifically, the irradiated areas of the coating film condense to some extent, becoming more metal oxide-rich, but the degree of condensation is generally moderate even without significant heating, and therefore the irradiated material becomes relatively insoluble in conventional developers.

[0171] For negative-tone imaging, the developer can be an organic solvent, such as the solvent used to form the resist solution. Generally, the choice of developer can be influenced by the solubility parameters of the coating film components (the chemical components of the irradiated and non-irradiated areas), as well as the developer's volatility, flammability, toxicity, viscosity, and potential chemical interactions with other process materials. In particular, suitable developers include, for example, aromatic compounds (e.g., benzene, xylene, toluene), esters (e.g., propylene glycol monomethyl ester acetate, ethyl acetate, ethyl lactate, n-butyl acetate, butyrolactone), alcohols (e.g., 4-methyl-2-pentanol, 1-butanol, isopropanol, 1-propanol, methanol), ketones (e.g., methyl ethyl ketone, acetone, cyclohexanone, 2-heptanone, 2-octanone), ethers (e.g., tetrahydrofuran, dioxane, anisole), and the like. Development may be carried out for from about 5 seconds to about 30 minutes, in further embodiments from about 8 seconds to about 15 minutes, and in additional embodiments from about 10 seconds to about 10 minutes. A person of ordinary skill in the art will recognize that additional ranges within the explicit ranges above are contemplated and are within the present disclosure.

[0172] For positive-tone imaging, the developer can generally be an aqueous acid or base solution. In some embodiments, an aqueous base solution can be used to obtain sharper images. To reduce contamination from the developer, it may be desirable to use a developer that does not contain metal atoms. Thus, quaternary ammonium hydroxide compositions, such as tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, or combinations thereof, are desirable as developers. In general, quaternary ammonium hydroxides of particular interest are those of the formula R 4NOH (where R = methyl, ethyl, propyl, butyl, or combinations thereof). The coating materials described herein can generally be developed with the same developers currently commonly used for polymer resists, specifically tetramethylammonium hydroxide (TMAH). Commercially available TMAH is available at 2.38 wt. %, and this concentration can be used for the processes described herein. Additionally, mixed quaternary tetraalkylammonium hydroxides can be used. Generally, the developer can include from about 0.5 to about 30 wt. %, in further embodiments from about 1 to about 25 wt. %, and in other embodiments from about 1.25 to about 20 wt. % of a tetraalkylammonium hydroxide or similar quaternary ammonium hydroxide. A person of ordinary skill in the art will recognize that additional ranges of developer concentrations within the explicit ranges above are contemplated and are within the present disclosure.

[0173] In addition to the main developer composition, the developer can contain additional compositions to facilitate the development process. Suitable additives include, for example, dissolved salts having a cation selected from the group consisting of ammonium, d-block metal cations (e.g., hafnium, zirconium, lanthanum), f-block metal cations (e.g., cerium, lutetium), p-block metal cations (e.g., aluminum, tin), alkali metals (e.g., lithium, sodium, potassium), and combinations thereof, and an anion selected from the group consisting of fluorine, chlorine, bromine, iodine, nitrate, sulfate, phosphate, silicic acid, boric acid, peroxide, butoxide, formate, oxalate, ethylenediamine-tetraacetic acid (EDTA), tungstic acid, molybdic acid, and the like, and combinations thereof. Other potentially useful additives include, for example, molecular chelating agents, such as polyamines, alcoholamines, amino acids, carboxylic acids, or combinations thereof. When optional additives are present, the developer can contain up to about 10% by weight of the additives, and in further embodiments up to about 5% by weight of the additives. A person of ordinary skill in the art will recognize that additional ranges of additive concentrations within the explicit ranges above are contemplated and are within the present disclosure. Additives can be selected to improve contrast, sensitivity, and linewidth roughness. Additives in the developer can also suppress metal oxide particle formation and precipitation.

[0174] For weaker developers, such as less concentrated aqueous developers, diluted organic developers, or compositions (where the coating has a lower development rate), a higher temperature development process can be used to increase the speed of the process. For stronger developers, the temperature of the development process can be lowered to slow down the rate of development and / or control the development kinetics. In general, the temperature of development can be adjusted between appropriate values ​​consistent with the volatility of the solvent. Furthermore, the developer containing dissolved coating film components near the developer-coating interface can be dispersed by sonication during development.

[0175] The developer can be applied to the coating film containing the latent image using any reasonable means. For example, the developer can be sprayed onto the patterned coating material. Spin coating can also be used. For automated processing, a puddle method, which involves statically pouring the developer onto the coating material, can be used. If desired, spin rinsing and / or drying can be used to complete the development process. Suitable rinsing solutions include, for example, ultrapure water, methyl alcohol, ethyl alcohol, propyl alcohol, and combinations thereof in the case of negative patterning, and ultrapure water in the case of positive patterning. After the image is developed, the coating film is disposed on the substrate as a patterned coating film.

[0176] Once the development step is complete, the patterned coating film may be heat treated to further condense the material and further dehydrate, densify, or remove residual developer from the material. While this heat treatment may be particularly desirable for embodiments in which the oxide coating material is incorporated into the final device, it may also be desirable to perform the heat treatment for some embodiments in which the coating film is used as a resist and ultimately removed if stabilization of the coating film is desired to facilitate further patterning. In particular, baking of the patterned coating film may be performed under conditions that result in the patterned coating film exhibiting a desired level of etch selectivity. In some embodiments, the patterned coating film may be heated to a temperature of about 100 to about 600°C, in further embodiments from about 175 to about 500°C, and in additional embodiments from about 200 to about 400°C. Heating may be performed for at least about 1 minute, in other embodiments from about 2 minutes to about 1 hour, and in further embodiments from about 2.5 minutes to about 25 minutes. Heating may be performed in air, vacuum, or an inert gas atmosphere such as Ar or N. A person of ordinary skill in the art will recognize that additional ranges of temperature and time for thermal treatment within the explicit ranges above are contemplated and are within the present disclosure. Similarly, non-thermal treatments, including blanket UV exposure or exposure to an oxidizing plasma, such as O, may be used for similar purposes.

[0177] In conventional organic resists, when the aspect ratio (height divided by width) of a structure becomes very large, the structure is prone to pattern collapse. Pattern collapse can be related to the mechanical instability of high-aspect-ratio structures, where forces associated with the processing step, such as surface tension, deform the structural elements. Low-aspect-ratio structures are more stable with respect to potential deformation forces. Using the dry process precursors and wet process resist solutions described herein, structures with thinner coating films can be effectively processed, thereby achieving improved patterning without the need for high-aspect-ratio patterned coating films. Thus, very high-resolution features were formed without relying on high-aspect-ratio features in the patterned coating films.

[0178] The resulting structures can have sharp edges and very low linewidth roughness. In particular, in addition to being able to reduce linewidth roughness, the high contrast also enables the formation of small features and spaces between features, as well as the ability to form very well-resolved two-dimensional patterns (e.g., sharp corners). Thus, in some embodiments, adjacent linear portions of adjacent structures can have an average pitch (half pitch) of about 60 nm (30 nm half pitch) or less, in some embodiments about 50 nm (25 nm half pitch) or less, and in further embodiments about 34 nm (17 nm half pitch) or less.

[0179] Pitch can be evaluated by design and confirmed by scanning electron microscopy (SEM), e.g., top-down imaging. As used herein, pitch refers to the spatial period, i.e., center-to-center distance, of repeating structural elements, and as commonly used in the art, half-pitch is half the pitch. Feature dimensions of a pattern can also be expressed in terms of the average width of the feature, typically evaluated away from corners, etc. Feature can also refer to the gaps between and / or material elements. In some embodiments, the average width can be about 25 nm or less, further embodiments about 20 nm or less, and in additional embodiments about 15 nm or less. Average linewidth roughness can be about 5 nm or less, in some embodiments about 4.5 nm or less, and further embodiments about 2.5 to about 4 nm. Linewidth roughness evaluation is performed by deriving the 3σ deviation from the average linewidth through analysis of top-down SEM images. The average contains both high-frequency and low-frequency roughness, i.e., short correlation lengths and long correlation lengths, respectively. While the linewidth roughness of organic resists is primarily characterized by a long correlation length, the organometallic coating materials of the present embodiments exhibit a significantly shorter correlation length. In the pattern transfer process, the short correlation roughness can be smoothed out during the etching process to produce a much higher fidelity pattern. A person of ordinary skill in the art will recognize that additional ranges of pitch, average width, and linewidth roughness within the explicit ranges above are contemplated and are within the scope of the present disclosure.

[0180] <Further Processing of Patterned Coating Film> After forming a patterned coating film on a substrate, the substrate can be further processed to facilitate the formation of a selected device. Furthermore, deposition of additional materials, etching, and / or patterning can typically be performed to complete the structure. The patterned coating film may or may not be ultimately removed. In either case, it is desirable to improve the quality of the patterned coating film to form improved devices (e.g., devices with a smaller footprint, etc.).

[0181] Alternatively or additionally, deposition of additional material according to a mask pattern can modify the properties of the underlying structure and / or provide contact with the underlying structure. The additional coating material can be selected based on the desired material properties. In addition, the density of the patterned inorganic coating material can provide a high implant resistance so that ions can be selectively implanted into the underlying structure through the openings in the mask. In some embodiments, the additionally deposited material can be a dielectric, semiconductor, conductor, or other suitable material. The additionally deposited material can be deposited using any suitable means, such as a solution-based procedure, chemical vapor deposition (CVD), sputtering, physical vapor deposition (PVD), or other suitable means.

[0182] Generally, multiple additional layers can be deposited. Additional patterning can be performed in conjunction with the deposition of multiple layers. If desired, any additional patterning can be performed using additional amounts of the coating materials described herein, polymer-based resists, other patterning means, or combinations thereof.

[0183] As described above, the patterned coating film may or may not be removed. If the patterned coating film is not removed, the patterned coating film is incorporated into the structure. In the embodiment in which the patterned coating film is incorporated into the structure, the properties of the patterned coating film can be selected to provide not only the desired patterning properties, but also the properties of the material within the structure.

[0184] When removal of the patterned coating film is desired, the patterned coating film functions as a conventional resist. The patterned coating film is used to pattern subsequently deposited materials and / or selectively etch the substrate through spaces within the condensed coating material before removal. The condensed coating material can be removed using an appropriate etching process. Specifically, to remove the condensed coating material, dry etching can be performed using, for example, BCl plasma, Cl plasma, HBr plasma, Ar plasma, or other suitable process gas plasma. Alternatively or additionally, wet etching can be used to remove the patterned coating material, for example, using an aqueous acid or base solution, HF (water), or buffered HF (water) / NHF, or oxalic acid.

[0185] The resist material can be utilized to perform multiple patterning. That is, the process can be applied to multiple coatings and multiple patterning. With regard to multiple patterning, a notable difference between the inorganic coating materials described herein and conventional organic resists is that the organic resists remain soluble in conventional resist casting solvents even after thermal baking. The resist materials described herein can be hardened by thermal baking, thereby becoming insoluble in organic solvents, allowing subsequent coating layers and the like to be formed on the resist material.

[0186] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention. In the examples, "parts" and "%" are by mass unless otherwise specified.

[0187] Unless otherwise specified, the following raw materials were used: [Organic solvents] Dehydrated hexane: n-hexane (dehydrated) (Kanto Chemical Co., Ltd.)

[0188] [Monoalkyltin compound (precursor)] Each tin compound may be referred to as follows: Tin compound corresponding to RSnX3 (A1) iPrSn(NMe2)3: isopropyltris(dimethylamido)tin, 119 Sn-NMR: -64 ppm... Compound (1) - Tin compound corresponding to RSnX2Y (B1) iPrSn(NMe2)2(NMeCH2NMe2), 119 Sn-NMR: -82ppm... Compound (4)

[0189] [Impurity tin compounds (A2, A3)] Tin compound (A2): iPrSn(NMe): diisopropyl form 119 Sn-NMR: -18 ppm...Compound (2) Tin compound (A3): Sn(NMe2)4: tetrakisamide 119 Sn-NMR: -120 ppm...Compound (3) Tin compounds other than compounds (1) to (4): Other impurities

[0190] <<Preparation and Analysis of Monoalkyltin Compounds (Precursors)>> The precursors were prepared to have the compositions of the following Comparative Examples and Examples, and the detailed compositions of the functional groups in the obtained precursors are shown in Tables 1 and 2. The abbreviations for substituents in Table 2 are as follows: iPr: isopropyl, isopropyl group, molecular formula C3H7 OtAm: tertiary amyloxy group OiPr: isopropoxy group NMe2: dimethylamino group OMePen: 4-methyl-2-pentanoxy group

[0191] [Precursor Containing Isopropyltris(dimethylamido)tin] Precursors L1A to L1E containing monoalkyltin compounds (A1) and / or (B1) were prepared according to the methods described below, and their analytical values ​​are shown in Table 1 below.

[0192] Example 1-2 (Method for Producing Precursor L1B) A 200 L light-shielded glass reactor (jacketed with circulating water), a cooling condenser with an internal coil, a stirring device (stirring blade: Twin Star, diameter: 350 mm, width: 110 mm, made of Teflon (registered trademark)-coated SUS), and a 50 L glass dropping device were prepared and used.

[0193] The reactor was depressurized to 3 kPa and then purged with nitrogen three times. Hexane (36.6 kg, water content 21 ppm) and n-butyllithium [41.0 kg, 96.8 mol (3.09 eq), 15% hexane solution (containing hexane equivalent to 34.9 kg)] were added, and while stirring at 150 rpm [impeller tip speed (m / s) = 3.14 × 0.35 × 150 / 60 = 2.74 (m / s)], dimethylamine (8.69 kg, 193.6 mol, 6.18 eq) was added dropwise over 1 hour while maintaining the temperature between -5 and 10 °C. The resulting lithium dimethylamide slurry was stirred at 23-27 °C for 1 hour.

[0194] The temperature of the obtained lithium dimethylamide slurry was adjusted to -10°C, and a hexane solution (4.20 kg in terms of hexane) containing isopropyltrichlorotin (8.40 kg, 31.3 mol, 1.00 eq) was added dropwise from a glass dropping device over 2 hours while maintaining the temperature within the temperature range (internal temperature -10°C to 0°C). Thereafter, the dropping device was washed with hexane (0.61 kg) while the solution was added dropwise.

[0195] After the dropwise addition, the temperature was raised to 25°C over 3 hours and then stirred for 16 hours. The resulting reaction solution was filtered using a pressure filter to remove the white solid (LiCl), yielding a clear filtrate. The white solid was further washed with dehydrated hexane (7.3 kg x 3), and the filtrates were combined. The resulting reaction solution was concentrated under reduced pressure. The resulting concentrated liquid (10.3 kg) was loaded into a light-shielded glass simple distillation apparatus still under a nitrogen atmosphere. The mixture was introduced into the distillation apparatus under a nitrogen inert gas atmosphere, and simple distillation was carried out under reduced pressure and heating to obtain the corresponding tin compound (1). The monoalkyltin composition obtained by this distillation was designated as precursor L1B. (Distillation conditions) Distillation apparatus: glass simple distillation apparatus wrapped in a light-shielding cloth Distillation conditions: internal temperature: 70-80°C, vacuum: 0.3 kPa

[0196] Example 1-1 Precursor L1A: A monoalkyltin composition obtained by placing the same monoalkyltin composition as precursor L1B in a flask equipped with a cooling condenser under a nitrogen atmosphere and heating the composition at reflux at 100° C. for 18 hours.

[0197] Example 1-2 Precursor L1B: The monoalkyltin composition described above as "Precursor L1B."

[0198] Comparative Example 1-1 Precursor L1C: A monoalkyltin composition obtained by subjecting the same monoalkyltin composition as precursor L1B to precision distillation purification in a distillation column having 30 theoretical plates at a reflux ratio of 10. Compound (4), i.e., a tin compound corresponding to RSnX2Y(B1), was not detected.

[0199] Example 1-3 Precursor L1D: A monoalkyltin composition obtained by mixing precursors L1A and L1C in a mass ratio of 50:50 under a nitrogen atmosphere.

[0200] Example 1-4 Precursor L1E: A monoalkyltin composition obtained by mixing precursor L1B and iPr2Sn(NMe2)2 (tin compound (2)) in a mass ratio of 90:10 under a nitrogen atmosphere.

[0201]

[0202] Precursors L2A to L2F containing the monoalkyltin compound (A1) and / or (B1) were prepared according to the method described below, and their analytical values ​​are shown in Table 2 below.

[0203] Comparative Example 2-1: Preparation of precursor L2C (precursor containing isopropyltris(t-amyloxy)tin: iPrSn(OtAm)3) A 100 mL two-neck flask (light-shielded) equipped with a tightly sealed magnetic stirrer (stirring: rod-shaped stirrer tip, diameter 15 mm, material PTFE) and a cooling condenser (cooling water 10°C) was used. The pressure was reduced to 3 kPa and then replaced with nitrogen three times. Hexane (5.0 mL, water content 10 ppm) and isopropyltris(dimethylamido)tin (5.0 g, 16.8 mmol, precursor L1B) were added and stirred at 1000 rpm. The internal temperature was adjusted to 20°C in a temperature-controlled water bath. Thereafter, while stirring at 1000 rpm [impeller tip speed (m / s) = 3.14 × 0.015 × 1000 / 60 = 0.785 (m / s)], t-amyl alcohol (manufactured by MERCK Corporation, water content 15 ppm) (4.60 g, 52.1 mmol, 3.1 eq) at 22°C was added while maintaining the temperature in the range of 20 to 30°C. Thereafter, the temperature was raised to 50°C and stirred for 3 hours. The resulting reaction solution was filtered under nitrogen for 5 minutes using a glass filter (filter: Kiriyama Mfg. Co., Ltd., Kiriyama funnel filter paper 5B, 60 mm diameter, the entire filter was shielded from light) to obtain a clear filtrate. The resulting reaction solution was stirred and shielded from light, and solvent concentration was carried out under reduced pressure (10 hPa, 40°C) until no further distillate was observed, yielding a concentrated solution of a synthetic tin compound containing isopropyltris(t-amyloxy)tin. The resulting concentrated solution was filled into a light-shielded glass container (brown glass container) under a nitrogen atmosphere. The resulting isopropyltris(t-amyloxy)tin after the reaction was identified by NMR, and its 119 The purity measured by Sn-NMR was 99.3 mol %, and no compound corresponding to RSnX2Y(B1) was detected. This was designated as precursor L2C.

[0204] [NMR analysis results of iPrSn(OtAm)3] 119 Sn-NMR (223.8 MHz; C6D6): δ -218ppm. ・ 1H-NMR (400 MHz; C6D6): δ 1.5-1,6 (m, 7H, (iPr:1H, tAm3:6H)), 1.28 (s, 18H, tAm3), 1.22 (d, 6H, iPr), 0.94 (t, 9H, tAm3).

[0205] Example 2-1: Preparation of precursor L2A (precursor containing iPrSn(NMe2)2(OiPr)) A 30 mL two-neck flask (light-shielded) equipped with a tightly sealed magnetic stirrer (stirring: rod-shaped stirrer tip, diameter 10 mm, material PTFE) and a cooling condenser (cooling water 10°C) was used. The pressure was reduced to 3 kPa and then replaced with nitrogen three times. Hexane (1.5 mL, water content 10 ppm) and isopropyltris(dimethylamido)tin (1.75 g, 5.96 mmol, precursor L1B) were added and stirred at 1000 rpm, and the temperature was adjusted to 0°C. Then, while stirring at 1000 rpm, isopropyl alcohol (Kanto Chemical Co., Inc., dehydrated grade) (17.9 mg, 0.30 mmol, 0.05 eq) at 22°C was added while maintaining the temperature in the range of 0 to 10°C. After stirring at 0°C for 1 hour, the obtained The resulting reaction solution was filtered under nitrogen for 5 minutes using a glass filter (filter: Kiriyama Mfg. Co., Ltd., Kiriyama Funnel Filter Paper 5B, 60 mm diameter, the entire filter was shielded from light) to obtain a clear filtrate. The resulting reaction solution was stirred and shielded from light, while the solvent was concentrated under reduced pressure (10 hPa, 40°C) until no more distillate was observed, yielding a tin composition containing isopropylbis(dimethylamino)(isopropoxy)tin (iPrSn(NMe2)2(OiPr)). The resulting tin composition was filled into a light-shielded glass container (brown glass container) under a nitrogen atmosphere. The resulting tin composition was used to identify the tin by NMR, and its 119 Measurement by Sn-NMR revealed that the precursor contained 5 mol % of (iPrSn(NMe2)2(OiPr)) and 93 mol % of (iPrSn(NMe2)3) as monoalkyltin compounds. This precursor is designated as precursor L2A.

[0206] [NMR analysis results of iPrSn(NMe2)2 (OiPr)] 119Sn-NMR (223.8 MHz; C6D6): δ-105 ppm ・ 1 H-NMR (400 MHz; C6D6): δ 4.1 (m, 1H OiPr), 2.7 (s, 12H NMe2), 1.6 (m, 1H iPr), 1.2 (m, 12H (OiPr:6H iPr:6H)).

[0207] Example 2-2: Preparation of Precursor L2B (Precursor containing iPrSn(OtAm)2(NMe2)) A 30 mL two-neck flask (light-shielded) equipped with a tightly sealed magnetic stirrer (stirring: rod-shaped stirrer tip, 10 mm diameter, made of PTFE) and a cooling condenser (cooling water 10°C) was used. The pressure was reduced to 3 kPa and then nitrogen-purged three times. Hexane (1.5 mL, water content 10 ppm) and isopropyltris(dimethylamido)tin (1.75 g, 5.96 mmol, precursor L1B) were added, stirred at 1000 rpm, and the temperature was adjusted to 0°C. Then, while stirring at 1000 rpm, 22°C t-amyl alcohol (MERCK Corporation, water content 15 ppm) (1.05 g, 11.9 mmol, 2.0 eq) was added while maintaining the temperature in the 0-10°C range. The mixture was then heated to 20°C and stirred for 1 hour. The resulting reaction solution was then filtered under nitrogen for 5 minutes using a glass filter (filter: Kiriyama Mfg. Co., Ltd., Kiriyama Funnel Filter Paper 5B, 60 mm diameter, the entire filter was shielded from light). A clear filtrate was obtained. While stirring the resulting reaction solution in the dark, the solvent was concentrated under reduced pressure (10 hPa, 40°C) until no further distillate was detected, yielding a tin composition containing isopropylbis(t-amyloxy)(dimethylamino)tin (iPrSn(OtAm)2(NMe2)). The resulting composition was filled into a light-shielded glass container (brown glass container) under a nitrogen atmosphere. The obtained tin composition was identified by NMR. 119 As a result of Sn-NMR measurement, the monoalkyltin compounds were iPrSn(OtAm)2(NMe2) at 77 mol%, iPrSn(OtAm)3 at 12 mol%, and iPrSn(OtAm)(NMe2) at 12 mol%. 2 This precursor was named precursor L2B.

[0208] [NMR Analysis Results of iPrSn(OtAm)2 (NMe2)] ・ 119 Sn-NMR (223.8 MHz; C6D6): δ -165 ppm ・ 1 H-NMR (400 MHz; C6D6): δ 2.7(s, 6H NMe2), 1.4 - 1.6 (m, 5H (iPr:1H, tAm2:4H)), 1.3 (d, 6H, iPr), 1.2 (s, 12H tAm2)), 0.9 (t, 6H tAm2))

[0209] [iPrSn(OtAm)(NMe2) 2 's NMR analysis results] ・ 119 Sn-NMR (223.8 MHz; C6D6): δ -111 ppm ・ 1 H-NMR (400 MHz; C6D6): δ 2.7(s, 12H NMe2), 1.4 - 1.6 (m, 3H (iPr:1H, tAm:2H)), 1.3 (d, 6H, iPr), 1.2 (s, 6H tAm)), 0.9 (t, 3H tAm))

[0210] Example 2-3 Preparation of Precursor L2D (Precursor containing isopropylbis(t-amyloxy)(4-methyl-2-pentanoxy)tin: iPrSn(OtAm)2 (OMePen)) A 30 mL two-neck flask (light-shielded) equipped with a tightly sealed magnetic stirrer (stirring: rod-shaped stirrer tip, diameter 10 mm, material PTFE) and a cooling condenser (cooling water 10°C) was used. The pressure was reduced to 3 kPa and then the contents were replaced with nitrogen three times. Hexane (1.5 mL, water content 10 ppm) and isopropyltris(dimethylamido)tin (1.75 g, 5.96 mmol, precursor L1B) were added, stirred at 1000 rpm, and the temperature was adjusted to 0°C. Then, while stirring at 1000 rpm, t-amyl alcohol (manufactured by MERCK, water content 15 ppm) (1.05 g, 11.9 mmol, 2.0 eq) at 22°C was added while maintaining the temperature in the range of 0 to 10°C. Then, the temperature was raised to 20°C and stirred for 1 hour, after which 4-methyl-2-pentanol (manufactured by TCI, referred to as "MePenOH") (0.61 g, 5.96 mmol, 1.0 eq) was added while maintaining the temperature at 20 to 25°C. The mixture was then heated to 50°C and stirred for 2 hours. The resulting reaction solution was then filtered under nitrogen for 5 minutes using a glass filter (filter: Kiriyama Mfg. Co., Ltd., Kiriyama Funnel Filter Paper 5B, 60 mm diameter, the entire filter shielded from light) to obtain a clear filtrate. The resulting reaction solution was stirred in the dark and subjected to solvent concentration under reduced pressure (10 hPa, 40°C) until no further distillate was observed, yielding a concentrated solution of a synthetic tin compound containing isopropyltris(t-amyloxy)tin. The resulting concentrated solution was filled into a light-shielded glass container (brown glass container) under a nitrogen atmosphere. The resulting tin composition after the reaction was used to identify the compound by NMR, and its 119 Measurement by Sn-NMR revealed that the monoalkyltin compound was 71 mol % isopropylbis(t-amyloxy)(4-methyl-2-pentanoxy)tin and 18 mol % iPrSn(OtAm)3, which was designated as precursor L2D.

[0211] [NMR analysis results of iPrSn(OtAm)2 (OMePen)] 119Sn-NMR (223.8 MHz; C6D6): δ-215ppm ・ 1 H-NMR (400 MHz; C6D6): δ 4.1 (Br, 1H), 1.7(m, 2H MePen) 1.5-1,6 (m, 6H (iPr:1H, tAm2:4H, MePen:1H)), 1.3 (d, 6H, iPr), 1.2 (m, 15H (3H: MePen) 12H: tAm2)), 0.9 (m, 12H (6H:MePen 6H:tAm2))

[0212] Example 2-4 Preparation of Precursor L2E Precursors L2C and L2B were mixed in a liquid state in a mass ratio of 90:10 under a nitrogen atmosphere to obtain precursor L2E.

[0213] Example 2-5 Preparation of Precursor L2F Precursors L2C and L2D were mixed in a liquid state in a mass ratio of 90:10 under a nitrogen atmosphere to obtain precursor L2F.

[0214]

[0215] <<Preparation and Analysis of Tin Hydrolysates by Hydrolysis>> <Example 3-1: Tin Hydrolysate H1A> Under an inert gas atmosphere and in the dark, 1.0 g (3.4 mmol, calculated as iPrSn(NMe2)3) of precursor L1A was added to 10 mL of anhydrous hexane using an airtight syringe. The resulting solution was cooled in an ice bath, and while stirring at 200 rpm, demineralized water (18.2 MΩ) (1.0 mL) was added over 3 minutes while maintaining the temperature at 0-10°C. This resulted in the formation of a white solid slurry. This was further stirred for 10 minutes while maintaining the temperature at 0-10°C. The slurry was then filtered through filter paper (Kiriyama Funnel Filter Paper 5B) to obtain a white solid. The solid was rinsed twice with demineralized water (18.2 MΩ) (3.0 mL) and collected in a 20 mL glass vial. The glass vial was vacuum dried at 40°C for 8 hours to obtain a white solid tin hydrolysate H1A.

[0216] The composition and crystallinity of the obtained tin hydrolysate were analyzed using the following measuring equipment and conditions. 119The sum of the peak integral values ​​of five-coordinate Sn (-250 to -350 ppm) in Sn-NMR is defined as k1, and the sum of the peak integral values ​​of six-coordinate Sn (-450 to -600 ppm) is defined as k2. 119 The total value of all peak integral values ​​(including k1 and k2) in the range of 1000 to -1000 ppm detected by Sn-NMR was defined as k3, and the ratio [(k1+k2) / (k3)] to this k3 was calculated.

[0217] [Analytical Equipment and Methods] NMR analyzer: Bruker, Avance Neo, 600 MHz, Probe: cryo 5 mm BBO; ESI-MS analyzer: Waters, Xevo G2-XS Qtof, Measurement mode: ESI positive, Solvent: Acetonitrile; XRD analyzer: PANalytical, X'Pert Pro MPD, X-ray source: CuKα focusing optical system, Scan range: 3 to 50°, Half-width analysis method: Profile fitting method (Pearson-VII function, pseudo-Voigt function) was used to separate peaks within the scan range and calculate the half-width of each peak. The diffraction angle 2θ (°) of the peak top with the maximum intensity within the scan range and the half-width of that peak were recorded. The number of peak tops within the diffraction angle 2θ (°) range of 5.00 to 15.00° were also recorded.

[0218] Examples 3-1 to 3-4, Comparative Example 3-1 The same procedure as in Example 3-1 was carried out (the precursor amount was standardized to 1.0 g, and the same amounts of other reagents were used) except that the precursor in Example 3-1 was changed to precursors L1B to L1E as shown in Table 3 below, to obtain tin hydrolysates H1B to H1E shown below. The compositions and crystallinity of the obtained tin hydrolysates were analyzed, and the results are also shown in Table 3 below. As a result of XRD analysis of tin hydrolysate H1A of Example 3-1, an XRD chart of H1A is shown in FIG. 1, and as a result of XRD analysis of hydrolysate H1C of Comparative Example 3-1, an XRD chart of H1C is shown in FIG. 2.

[0219]

[0220] [Analysis results of tin hydrolysate H1A] (R = isopropyl, chemical formula C3H7) 119 As a result of Sn-NMR measurement, as shown in Table 3, a 1:1 peak was observed at SnNMR (MeOD): 5-coordinate (RSnO4): -337 ppm, and 6-coordinate (RSnO5): -513 ppm. This corresponds to the tin dodecamer cluster (nBuSn) reported in Organometallics 19, 2000, 1940-1949. 12 O 14 This correlates with the NMR results of (OH)6, i.e., the composition formula RSnO (3 / 2-x / 2) (OH) x A compound corresponding to the compound was obtained. In addition, since no peaks other than k1 and k2 were present with detectable intensity, the value of (k1 + k2) / (k3), which indicates purity, was 0.99 or more. In addition, as a result of the analysis of tin hydrolyzate H1A, the compound shown in Figure 3A was obtained. 119 A wide range chart of Sn-NMR is shown in Figure 3B. 119 A detailed chart of Sn-NMR is shown in Figure 3C. 1 A detailed H-NMR chart is shown.

[0221] As a result of electrospray ionization mass spectrometry (ESI-MS) analysis of the tin hydrolyzate H1A, the ESI-MS chart of H1A is shown in FIG. 3D. In this chart, the composition formula RSnO (3 / 2-x / 2) Divalent ions (specifically, chemical formula [(C3H7Sn) 12 O 14 (OH) +2 Peaks corresponding to singly charged ions (m / z = approximately 2268), calculated m / z = approximately 1134, and adducts of these ions, such as potassium (m / z = +40), were observed.

[0222] [Analysis results of tin hydrolysates H1B to H1E] For tin hydrolysates H1B to H1D, NMR and ESI-mass measurements yielded results similar to those for tin hydrolysate H1A, and the chemical formula and purity were comparable. For tin hydrolysate H1E, an impurity corresponding to RSnO (a structure formed by hydrolysis of a dialkyl impurity) was observed in the vicinity of -200 to -240 ppm in Sn-NMR.

[0223] Examples 4-1 to 4-5, Comparative Example 4-1 By changing precursors to L2A to L2F, tin hydrolysates H2A to H2F were obtained by the method described below, and the obtained tin hydrolysates were analyzed. The results are shown in Table 4.

[0224] Example 4-1 Under an inert gas atmosphere and in the dark, 1.0 g (3.4 mmol, calculated as iPrSn(NMe)) of precursor L2A was added to 10 mL of dehydrated hexane using an airtight syringe. The resulting solution was cooled in an ice bath, and while stirring at 200 rpm, demineralized water (18.2 MΩ) (1.0 mL) was added over 3 minutes while maintaining the temperature at 0-10°C. This resulted in the formation of a white solid slurry. This was further stirred for 10 minutes while maintaining the temperature at 0-10°C. The slurry was then filtered using filter paper (Kiriyama Funnel Filter Paper 5B) to obtain a white solid. The solid was rinsed twice with demineralized water (18.2 MΩ) (3.0 mL) and collected in a 20 mL glass vial. The glass vial was then vacuum dried at 40°C for 8 hours to obtain a white solid tin hydrolyzate H2A.

[0225] Example 4-2 Under an inert gas atmosphere and in the dark, 2.0 g (4.7 mmol, calculated as iPrSn(OtAm)) of precursor L2B was added to 20 mL of dehydrated hexane using an airtight syringe. The resulting solution was cooled in an ice bath and stirred at 200 rpm. Demineralized water (18.2 MΩ) (2.0 mL) was added over 3 minutes while maintaining the temperature at 0-10°C. The mixture was further stirred for 10 minutes while maintaining the temperature at 0-10°C, then heated to 50°C over 1 hour and stirred for 1 hour at 50°C. The resulting mixture was rotated at 100 rpm in an evaporator, and the pressure was reduced to 3 kPa in a 50°C hot bath to remove the solvent, yielding a white solid. The resulting solid was dispersed in 20 mL of hexane to yield a slurry, which was then filtered through filter paper (Kiriyama Funnel Filter Paper 5B) to yield a white solid. The solid was rinsed twice with demineralized water (18.2 MΩ) (3.0 mL) and collected in a 20 mL glass vial, which was then vacuum dried at 40° C. for 8 hours to obtain a white solid tin hydrolyzate H2B.

[0226] Comparative Example 4-1 A white solid tin hydrolysate H2C was obtained in the same manner as in Example 4-2, except that the precursor was changed to L2C.

[0227] Examples 4-3 to 4-5 White solid tin hydrolysates H2D to H2F were obtained in the same manner as in Example 4-2, except that precursors L2D to L2F were used.

[0228]

[0229] [Analysis results of tin hydrolysates H2A to H2F] (R = isopropyl, chemical formula C3H7) 119 As a result of Sn-NMR measurement, as shown in Table 4, a 1:1 peak was observed at SnNMR (MeOD): 5-coordinate (RSnO4): -337 ppm, and 6-coordinate (RSnO5): -513 ppm. Furthermore, since no peaks corresponding to k1 and k2 were present with detectable intensity, the value of (k1 + k2) / (k3), which indicates purity, was 0.99 or more. In other words, for tin hydrolysates H2A to H2F, precursors having hydrolyzable groups X and Y with various structures were used as raw materials, but the obtained products were equivalent to tin hydrolysate H1A in terms of chemical formula and purity.

[0230] <<Solubility, Filterability, and Storage Stability of Resist Solution>> The resulting tin hydrolyzate is used to prepare a solution (resist solution) in a resist solvent by the following method. The resulting resist solution is subjected to a solubility test, a filtration test, and a storage stability test, and evaluated according to the following evaluation criteria.

[0231] <Examples 5-1 to 5-4, Comparative Example 5-1> Specifically, each of the tin hydrolysates (0.100 g) of H1A to H1E used in Examples 3-1 to 3-4 and Comparative Example 3-1 and 4-methyl-2-pentanol (4.90 g) was weighed into a 20 mL transparent glass vial to prepare a resist solution, and the vial containing the resist solution was placed in an ultrasonic generator containing water at room temperature (23° C.), and ultrasonic waves were applied for 5 minutes to perform dissolution.

[0232] [Method for Evaluating Solubility] The solubility of a tin hydrolyzate is evaluated by comparing the turbidity (transparency) when the tin hydrolyzate is dissolved in a resist solvent at a certain concentration. Specifically, 5.0 g of a 2.0% tin hydrolyzate mixture in 4-methyl-2-pentanol, as disclosed in JP-A-2019-500490, was prepared, and the turbidity (transparency) of the resulting solution was visually confirmed by comparing it with a standard turbidity solution to evaluate the solubility of the corresponding tin hydrolyzate. Kaolin turbidity standard solutions (0° (transparent), 50°, 100°, 500°, and 1000° (white turbidity)) specified in JIS K0110 were used as the standard turbidity solutions, and the turbidity closest to that of each standard turbidity solution was evaluated using the following evaluation criteria 1 to 5. (Evaluation criteria) Turbidity rating 1: 0 degrees (transparent) Turbidity rating 2: 50 degrees Turbidity rating 3: 100 degrees Turbidity rating 4: 500 degrees Turbidity rating 5: 1000 degrees (cloudy)

[0233] [Method for Evaluating Filterability] The filterability of a tin hydrolysate is evaluated by comparing the degree of clogging of a filter using a solution obtained by dissolving the tin hydrolysate at a constant concentration in a resist solvent. Specifically, 5.0 g of a mixed solution of 2.0% tin hydrolysate in 4-methyl-2-pentanol, as disclosed in JP-A-2019-500490, is prepared, and the degree of clogging when the solution is filtered is evaluated according to the following evaluation criteria. Specifically, the evaluation was performed by filtering 5.0 g of the mixed solution using a 10 mL syringe while applying pressure (approximately 300 kPa) to a filter with a pore size of 0.2 μm. (Filter used: 0.2 μm, made of PTFE, effective filtration area 4.0 cm) 2 (Advantech, Disposable Membrane Filter Unit DISMIC 25HP045AN) (Evaluation criteria) - If 5.0 g of filtration was possible without clogging, it was given a "1". - If 2.0 g or more was filtered and then clogged, it was given a "2". - If 2.0 g or less was filtered and then clogged, it was given a "3".

[0234] [Method for evaluating storage stability] In the filterability test, the resist solution after filter filtration was introduced into a brown glass vial (20 mL) in the air, and the vial was closed with a lid. In this state, it was stored for one month at 20°C under light-shielded conditions. After storage, the resist solution was transferred to a transparent vial and evaluated in the same manner as in the solubility evaluation, and the result was used as an evaluation of storage stability.

[0235]

[0236] That is, Tables 3 and 5 show that the tin hydrolysates shown in Examples 5-1 to 5-4, which were obtained using precursors containing an appropriate amount of RSnX2Y (B1) as raw materials, had high purity, low crystallinity, high solubility, and high storage stability.

[0237] Examples 6-1 to 6-5, Comparative Example 6-1 Using the same method as in Example 5-1, 5.0 g of a mixed solution of tin hydrolysates H2A to H2F corresponding to 2.0% in 4-methyl-2-pentanol was prepared. Using the resulting mixed solution, evaluations of solubility, filterability, and storage stability were carried out in the same manner as in Example 5-1. The results are shown in Table 6.

[0238]

[0239] That is, Tables 4 and 6 show that the tin hydrolysates shown in Examples 6-1 to 6-5, which were obtained using precursors containing an appropriate amount of RSnX2Y (B1) as raw materials, had high purity, high solubility, and high storage stability.

[0240] <<Preparation of Patterned Thin Films>> <Example 7> The tin hydrolyzate H1A obtained in Example 3-1 was dissolved in 4-methyl-2-pentanol (5 mL) using ultrasound to a concentration of 2.0%, and the resulting solution was filtered through a 0.2 μm syringe filter to obtain a transparent resist solution containing the tin hydrolyzate. A silicon wafer (Si substrate, 100 mm diameter) with an oxide surface was treated with ozone and used as a substrate for the deposition of a thin resist film. Prior to resist deposition, the surface of the Si substrate was treated with hexamethyldisilazane (HMDS) vapor. The resist solution was spin-coated onto the substrate at 2000 rpm and baked on a hot plate at 90°C for 2 minutes. The film thickness after coating and baking was measured to be approximately 22 nm using an ellipsometer. The coated substrate was then irradiated with ultraviolet light (light source: xenon excimer lamp (172 nm, 7.2 eV), manufactured by Ushio Inc., light source intensity: 0.7 mW / cm). 2 The film was exposed to a pattern using a developer (developer) and the pattern was projected onto the substrate. The substrate was then immersed in 2-heptanone for 15 seconds and rinsed in the same developer for an additional 15 seconds, forming a negative image, i.e., the unexposed portions of the film were removed, leaving only the pattern-exposed portions.

[0241] The resulting patterned thin film had high sensitivity and low LWR (line width roughness), making it an excellent resist material.

[0242] Although the above examples show specific embodiments of the present invention, the examples are merely illustrative and should not be construed as limiting. Various modifications that are obvious to those skilled in the art are intended to fall within the scope of the present invention.

Claims

1. A tin compound having a tin atom, an organic group R, and an oxo ligand and / or a hydroxo ligand, wherein the diffraction angle 2θ (°) of the maximum intensity peak in X-ray diffraction measurement is between 5.00 and 15.00°, the half-width of the maximum intensity peak is between 1.00 and 4.00°, and the organic group R has 1 to 30 carbon atoms.

2. The tin compound has the composition formula RSnO (3 / 2-X / 2) (OH) X 2. The tin compound according to claim 1, represented by the formula: (wherein 0≦x≦3).

3. The tin compound has the chemical formula (RSn) 12 O 14 (OH)6 +2 The tin compound according to claim 1, which is a compound containing a cation represented by the formula:

4. 119 The sum (k1 + k2) of the peak integral value sum (k1) of 5-coordinate Sn (-250 to -350 ppm) and the peak integral value sum (k2) of 6-coordinate Sn (-450 to -600 ppm) in Sn-NMR, 119 The tin compound according to any one of claims 1 to 3, wherein the ratio [(k1 + k2) / (k3)] of the total peak integral value (including k1 and k2) in the range of 1000 to -1000 ppm detected by Sn-NMR to the total value (k3) is 0.9 or more.

5. 119 The tin compound according to any one of claims 1 to 4, wherein the ratio (k1 / k2) of the total integral value (k1) of the peaks of five-coordinate Sn (-250 to -350 ppm) in Sn-NMR to the total integral value (k2) of the peaks of six-coordinate Sn (-450 to -600 ppm) is 0.5 to 2.

5.

6. A tin compound according to any one of claims 1 to 5, wherein the half-width at the maximum intensity peak is 1.43 to 4.00°.

7. The tin compound according to any one of claims 1 to 6, wherein the organic group R has 3 to 10 carbon atoms.

8. A tin compound according to any one of claims 1 to 7, wherein the organic group R is a hydrocarbon group.

9. The organic group R is a hydrocarbon group, and 50 mol % or more of the substituents constituting the hydrocarbon group are secondary hydrocarbon groups R 2 The tin compound according to any one of claims 1 to 7, 10. A resist solution comprising the tin compound according to any one of claims 1 to 9 and an organic solvent.

11. A method for forming a pattern, comprising the steps of applying the resist solution according to claim 10 to a substrate, exposing the substrate to radiation, and developing the resist solution with a developer.

12. A thin film on a substrate comprising a tin compound according to any one of claims 1 to 9.

13. A patterned thin film on a substrate comprising the tin compound according to any one of claims 1 to 9.

14. A method for manufacturing a substrate, comprising the pattern forming method according to claim 11.

15. RSnX ２ A monoalkyltin compound represented by Y(B1). (In the general formula (B1), R is an organic group having 1 to 30 carbon atoms. X and Y are hydrolyzable groups having different chemical formulas, and X is one of OR', NR', 2、 C≡CR', said Y being OR' Y , N.R.' Y 2、 C≡CR' Y The R′ and R′ Y is an organic group having 1 to 10 carbon atoms. Y In the case of 2, the above R', R' Y may be the same or different. Y When there are a plurality of groups, they may have different structures, or may be bonded to each other to form a cyclic structure.) 16. The hydrolyzable groups X and Y are NR'2 and NR' Y 2, wherein the substituent NR'2 of X and the substituent NR' of Y Y 16. The monoalkyltin compound of claim 15, wherein 2 is a different chemical formula.

17. The hydrolyzable groups X and Y are OR' and OR' Y The substituent OR′ of X and the substituent OR′ of Y Y and are different chemical formulas.

18. The hydrolyzable group X is a substituent NR'2 and the hydrolyzable group Y is a substituent OR' Y The monoalkyltin compound according to any one of claims 15 to 17, 19. The hydrolyzable group X is a substituent OR' and the hydrolyzable group Y is a substituent NR' Y 2. The monoalkyltin compound according to claim 15, wherein 20. Monoalkyltin compounds RSnX ３ 50 to 99.99 mol % of (A1), RSnX ２ A monoalkyltin composition comprising 0.01 mol % or more and less than 50 mol % of Y (B1). (In the general formulas (A1) and (B1), R is an organic group having 1 to 30 carbon atoms. X and Y are hydrolyzable groups having different chemical formulas, and X is one of OR', NR', 2、 C≡CR', said Y being OR' Y , N.R.' Y 2、 C≡CR' Y The R′ and R′ Y is an organic group having 1 to 10 carbon atoms. When X is NR'2 and / or Y is NR'2, R', R' Y may be the same or different. Y When there are a plurality of groups, they may have different structures, or may be bonded to each other to form a cyclic structure.) 21. Monoalkyltin compounds RSnX ３ (A1) is 0.01 mol% or more and less than 50 mol%; RSnX ２ A monoalkyltin composition comprising 50 to 99.99 mol % of Y(B1). (In the general formulas (A1) and (B1), R is an organic group having 1 to 30 carbon atoms. X and Y are hydrolyzable groups having different chemical formulas, and X is one of OR', NR', 2、 C≡CR', said Y being OR' Y , N.R.' Y 2、 C≡CR' Y The R′ and R′ Y is an organic group having 1 to 10 carbon atoms. When X is NR'2 and / or Y is NR'2, R', R' Y may be the same or different. Y When there are a plurality of groups, they may have different structures, or may be bonded to each other to form a cyclic structure.) 22. A monoalkyltin composition according to claim 20 or 21, comprising RSnX3 (A1), RSnX2Y (B1), and a monoalkyltin compound other than these, wherein the sum of the contents of RSnX3 (A1) and RSnX2Y (B1) is 80 mol% or more.

23. A method for producing a tin compound having a tin atom, an organic group R, and an oxo ligand and / or a hydroxo ligand, wherein the diffraction angle 2θ (°) of the peak of maximum intensity in X-ray diffraction measurement is between 5.00 and 15.00°, the half-width of the maximum intensity peak is between 1.00 and 4.00°, and the organic group R has 1 to 30 carbon atoms, the method comprising the following steps 1 and 2: <Step 1> Using the monoalkyltin composition according to claim 20 or 21 as a raw material. <Step 2> Contacting the raw material with water and / or water vapor.

24. The method for producing a tin compound according to claim 23, wherein in step 2, the mixture of the raw material and the organic solvent is contacted with liquid water.

25. A method for producing a tin compound according to claim 23 or 24, wherein step 2 comprises mixing 100 parts by mass of the raw material with 100 parts by mass of an organic solvent to form a composition.

26. A method for producing a tin compound according to any one of claims 23 to 25, wherein the half-width at the maximum intensity peak is 1.43 to 4.00°.

Images