Method for purifying alkoxysilicon compounds

Abstract

To provide a method for purifying an alkoxy compound that treats a purified alkoxysilicon compound containing metal impurities with a chelate resin having a functional group containing sulfur atoms and nitrogen atoms, thereby reducing an adsorption amount of the purified alkoxysilicon compound to the chelate resin and also reducing the metal impurities, and an alkoxysilicon compound.SOLUTION: A purified alkoxysilicon compound is treated with a chelate resin having a functional group represented by the following formulae (1-1) to (1-3). In formulae (1-1) to (1-3), * represents a joint end with a resin as a carrier.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an industrially useful method for purifying alkoxysilicon compounds in which the amount of metallic impurities that cause defects in the lithography process used in the manufacture of semiconductor devices is reduced. [Background technology]

[0002] Lithography coating film forming compositions used in lithography processes in the manufacture of semiconductor devices are required to reduce metal impurities that cause microdefects (eg, about 1 to 100 nm, called defects) on wafers. As a method for removing such metal impurities, a method of treating them with a silica gel column is known (Non-Patent Document 1), but the removal rate is low and it is not suitable for industrial scale use. In addition, a method using ion exchange resins is known as a method for removing metal impurities, but there are problems such as hydrolysis of alkoxysilanes and large adsorption of the target compound to the ion exchange resin, which results in poor purification efficiency from an economical standpoint. In addition, purification by distillation can also be used as a method for efficiently removing metal impurities, but there are problems with this method, such as its inapplicability when the compound to be purified is solid or has a high boiling point, or when the compound to be purified has low thermal stability. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Experimental Chemistry Lectures, Vol. 2, p. 114 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention has been made to solve such problems, and aims to treat an alkoxysilicon compound to be purified that contains metal impurities with a chelating resin having a functional group containing a specific atom, thereby obtaining a compound to be subjected to the treatment with the chelating resin.purification The object of the present invention is to provide a method for purifying an alkoxy compound, which can reduce the amount of alkoxy silicon compound adsorbed and reduce metal impurities, and an alkoxy silicon compound. [Means for solving the problem]

[0005] As a result of extensive research into achieving the above-mentioned object, the inventors have discovered a method for efficiently reducing metal impurities by treating an alkoxysilicon compound to be purified that contains metal impurities with a chelating resin having functional groups containing sulfur and nitrogen atoms, while suppressing adsorption of the alkoxysilicon compound to be purified to the chelating resin, thereby completing the present invention. That is, the present invention provides the following method for purifying an alkoxysilicon compound and the following alkoxysilicon compound. 1. A method for purifying an alkoxysilicon compound, which comprises treating an alkoxysilicon compound to be purified that contains metal impurities with a chelating resin having functional groups containing sulfur and nitrogen atoms. 2. The method for purifying an alkoxysilicon compound as described in 1 above, wherein the functional group is represented by any one of the following formulas (1-1) to (1-3): [ka] (In the formulas (1-1) to (1-3), * represents a bond end with the resin used as a carrier.) 3. A method for purifying an alkoxysilicon compound described in 1 or 2 above, characterized in that the alkoxysilicon compound to be purified, which contains metal impurities, is treated with a mixture containing the chelating resin or a mixture of the chelating resin and another chelating resin. 4. A method for purifying an alkoxysilicon compound described in 1 or 2, characterized in that the alkoxysilicon compound to be purified containing metal impurities is treated, one by one, with two or more resins selected from the group consisting of the chelating resin, a mixture containing the chelating resin, other chelating resins, and a mixture of the chelating resin and other chelating resins. 5. The method for purifying an alkoxysilicon compound according to any one of items 1 to 4, wherein the alkoxysilicon compound has a molecular weight of 5,000 or less. 6. The alkoxy silicon compound has a hydroxy group, an amino group or Allyl 6. The method for purifying an alkoxysilicon compound according to any one of items 1 to 5, wherein the alkoxysilicon compound is a compound obtained by reacting a compound having a group with an alkoxysilicon compound in the presence of a transition metal catalyst. 7. The alkoxy silicon compound Allyl 7. The method for purifying an alkoxysilicon compound according to 6 above, which is a compound obtained by reacting a compound having a group with an alkoxysilicon compound having a Si-H bond in the presence of a transition metal catalyst. 8. The method for purifying an alkoxysilicon compound according to 7 above, wherein the alkoxysilicon compound having a Si-H bond is a trialkoxysilane compound. 9. The alkoxy silicon compound Allyl The compound according to any one of the above items 1 to 4, which is obtained by reacting an isocyanuric acid derivative having a group with an alkoxysilicon compound having a Si-H bond. 9. A method for purifying an alkoxysilicon compound according to any one of claims 8 to 8. 10. An alkoxysilicon compound which is obtained by treating an alkoxysilicon compound to be purified that contains metal impurities with a chelating resin having functional groups containing sulfur and nitrogen atoms, and which has a residual metal impurity content of 1 ppm or less at 100% by weight. 11. The alkoxysilicon compound according to claim 10, wherein the residual metal is any one of Pt, Ir, Re, Ni, Mo, Fe, Ti, Ca, and Sr. Effect of the Invention

[0006] According to the method for purifying an alkoxysilicon compound of the present invention, metal impurities can be reduced economically and efficiently, regardless of the properties of the alkoxysilicon compound to be purified. Furthermore, regardless of the properties of the alkoxysilicon compound to be purified, an alkoxysilicon compound having reduced metal impurities can be obtained economically and efficiently. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] <Chelate resin> Chelate resins are resins that have chelating functional groups bound to the surface of a carrier resin such as polystyrene or crosslinked porous polystyrene. In the case of a porous carrier, it is possible to bind the chelating functional groups to the inside of the pores. By binding the chelating functional groups to the surface of the carrier, it is possible to efficiently contact metal impurities in the solution.

[0008] As the carrier in the chelating resin, silica or a substance containing a silica component can be used. The silica or the substance containing a silica component can be either a synthetic product or a natural product, but it is preferable to use a carrier that does not leach out impurities, such as a silica obtained by hydrolyzing a high-purity alkoxysilane. Synthetic quartz (SiO2) can be used, which is manufactured by molding and firing silica. Forsterite (2MgO SiO2), zircon (ZrO2 SiO2), mullite (3Al2O3 2SiO2), steatite (MgO SiO2), cordierite (2MgO 2Al2O3 5SiO2), etc. can be used as silica-containing materials.

[0009] When silica or a silica component-containing substance is modified with a chelating functional group, a silane coupling agent having a functional group capable of reacting with the end of the chelating functional group reacts with the silica component on the surface of the silica or silica component-containing substance particles to modify the surface and introduce the chelating functional group. Examples of the functional group capable of reacting with the end of the chelating functional group include vinyl groups, Allyl Examples of hydrolyzable groups include hydroxyl groups, halogen groups, epoxy groups, and thiol groups. Silane coupling agents can have one to three hydrolyzable groups, but three hydrolyzable groups are preferred due to their adhesion to the carrier. Chelate resins with chelating functional groups attached to silica particles can be packed into columns and used as is.

[0010] When modifying polystyrene with a chelating functional group, a chloromethyl group is introduced to the surface of the polystyrene particles using a chloromethylating agent (e.g., chloromethyl methyl ether), and the chloromethyl group is further reacted with the chelating functional group to introduce the chelating functional group into the polystyrene. The polystyrene is in the form of particles and can be used by packing it directly into a column.

[0011] When polystyrene is used as a carrier in a chelating resin, it is possible to use crosslinked porous polystyrene, which is highly crosslinked to prevent the elution of impurities. A divinyl compound is used as a crosslinking agent, and for example, divinylbenzene, divinylmethane, etc. can be used. In addition, it is preferable to use polystyrene with a large specific surface area as an adsorbent, and porous polystyrene can be used. Porous polystyrene can be obtained by adding a small amount of non-solvent during the polymerization of styrene.

[0012] The above carriers can be used in the form of particles. In the case of polystyrene or crosslinked porous polystyrene, the particles can have a particle diameter of, for example, about 1 μm to 10 mm, or about 1 μm to 1 mm, or about 10 μm to 1 mm. In the case of silica or a substance containing a silica component, the particles can have a particle diameter of about 1 μm to 1 mm, or about 1 μm to 500 μm, or about 10 μm to 100 μm.

[0013] The chelating resin used in the present invention is characterized by having a functional group containing a sulfur atom and a nitrogen atom. Specific examples of the chelating functional group containing a sulfur atom and a nitrogen atom include those represented by the following formulae (1-1) to (1-3). [ka] (In the formulas (1-1) to (1-3), * represents a bond end with the resin used as a carrier.)

[0014] There are no particular limitations on the type of material as long as it has these functional groups, and commercially available materials can be used.

[0015] The chelating resin used in the present invention generally exhibits the following metal adsorption capacity: The chelating resin having functional groups is effective in capturing metals such as Ag, Pt, Cu, Fe, Os, Pd, Rh, Sc, Sn, metal ions, and their metal hydroxide colloids and metal oxide colloids. In particular, platinum and palladium ions in organic solvents can be captured effectively. The amount of functional groups can be about 0.1 mmol to 5 mmol per gram of the chelating resin. Formula (1-1) is available as a chelating resin under the trade name MuromacXMS-5812 from Muromachi Chemical Co., Ltd. Formula (1-1) is available as a chelating resin under the trade name S914 from Purolite Co., Ltd.

[0016] Chelate resins having functional groups of formula (1-2) and formula (1-3) can capture many metals under various conditions, and are effective in capturing metals such as Ca, Cd, Cr, Cs, Cu, Fe, Ir, La, Mg, Os, Pd, Pt, Rh, Ru, Sc, Sn, and Zn, metals, metal ions, and their metal hydroxide colloids and metal oxide colloids. They are particularly suitable for capturing Sn and Pt ions, their metal hydroxide colloids, and their metal oxide colloids. The amount of functional groups can be about 0.1 mmol to 5 mmol per gram of chelate resin. Formula (1-2) is available as a chelate resin, trade name S920, from Purolite Co., Ltd. Formula (1-3) is available as a chelate resin, trade name MuromacXMS-5418, from Muromachi Chemical Co., Ltd.

[0017] The removal of metal impurities with a chelating resin is carried out by treating a solution obtained by redissolving an oily or solid alkoxysilicon compound to be purified in an organic solvent, or a solution containing an alkoxysilicon compound to be purified which has been synthesized and then post-treated, with a chelating resin by a contact catalyst method or a fixed bed method.

[0018] The contact catalyst method is a method in which the solution to be purified is mixed with a chelating resin, stirred for a certain period of time, and then the resin is removed by filtration.The fixed bed method is a method in which metal impurities are removed from the solution to be purified by passing the solution through a fixed bed such as a column or packed tower filled with a chelating resin.

[0019] The treatment is usually carried out once, but may be carried out multiple times, from 2 to 100 times. The treatment time (residence time) in the contact catalyst method varies depending on the type of alkoxysilicon compound to be purified and the type of chelating resin, the type of solvent used, and the amount of solvent used.

[0020] The amount of chelating resin used in the present invention will vary depending on the type of alkoxysilicon compound to be purified and the type of organic solvent used, but is typically about 0.01 to 1000% by mass, preferably 0.1 to 500% by mass, and more preferably 1 to 100% by mass, based on the amount of alkoxysilicon compound to be purified.

[0021] The chelating resin used in the present invention may be used alone or in a mixture of two or more kinds. In addition, a mixture of the chelating resin used in the present invention and other chelating resins may be used.

[0022] Furthermore, the treatment with the chelating resin can be carried out not only once but also multiple times, in which case the alkoxysilicon compound to be purified containing metal impurities can be treated with two or more resins selected from the group consisting of the chelating resin used in the present invention, a mixture containing the chelating resin used in the present invention, another chelating resin, and a mixture of the chelating resin used in the present invention and another chelating resin, one by one in sequence or simultaneously.

[0023] <Alkoxysilicon compound to be purified> The alkoxysilicon compound to be purified in the present invention can be either a commercially available product or one synthesized by a known method, and the metal impurities contained therein can be efficiently removed or reduced. Specific examples of commercially available alkoxysilicon compounds to be purified include the following compounds (2-1) to (2-28) manufactured by Shin-Etsu Chemical Co., Ltd. [ka]

[0024] The alkoxysilicon compound to be purified can be synthesized by known methods (e.g., WO2011 / 102470, WO2019 / 003767, JP2003-26809, etc.), such as by reacting trialkoxysilicon with a hydroxyl group, an amino group, or Allyl It can be obtained by reaction with a compound having a group. Specific examples include the compounds of the following formulas (3-1) to (3-19). [ka] [ka]

[0025] <Organic solvent> In the present invention, examples of the solvent used when treating the alkoxysilicon compound to be purified with a chelating resin include, but are not limited to, the organic solvents described below.

[0026] Examples of the organic solvent include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, cycloheptanone, cyclopentanone, cyclohex ... butyl methyl ether, 4-methyl-2-pentanol, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, ethyl ethoxyacetate, 2-hydroxyethyl acetate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate, 2-heptanone, methoxycyclopentane, anisole, γ-butyrolactone, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, n-heptane, hexane, isopropyl Ether, diisobutyl ether, diisoamyl ether, tert-butyl methyl ether, tetrahydrofuran 、 Examples of the solvent include 2-methyltetrahydrofuran and 2,5-dimethyltetrahydrofuran. These solvents can be used alone or in combination of two or more kinds.

[0027] Among these solvents, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, butyl lactate, cyclohexanone, n-heptane, hexane, toluene, isopropyl ether, diisobutyl ether, diisoamyl ether, tert-butyl methyl ether, cyclopentyl methyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, etc. are preferred. Particularly, propylene glycol monomethyl ether, cyclopentyl methyl ether, propylene glycol monomethyl ether acetate, toluene, and isopropyl ether are preferred.

[0028] The amount of the organic solvent used is not particularly limited as long as it can sufficiently dissolve the alkoxysilicon compound to be purified, but it is about 2 to 1000 parts by mass, preferably 4 to 100 parts by mass, relative to the alkoxysilicon compound to be purified.

Examples

[0029] <GC analysis conditions> The adsorption amounts shown in the examples described below are the measurement results by GC, and the measurement conditions and the like are as follows. Apparatus: GC-2010 Plus manufactured by Shimadzu Corporation Column: DB-1 Dimethylpolysiloxane, 0.25μm, 0.25mm×30m (Agilent Technologies, Inc.) Inlet temperature: 250 °C Split ratio: 100 Column temperature: 100 °C (held for 15 minutes), temperature increase (15 °C / min), 250 °C (held for 5 minutes), temperature increase (15 °C / min), 300 °C (held for 5 minutes) Linear velocity: 32.0 cm / sec Detector temperature: 300 °C (FID) Analysis time: 38.33 minutes Injection volume: 1.0 μL Dilution solvent: propylene glycol monomethyl ether (PGME), cyclopentyl methyl ether (CPME) or acetonitrile

[0030] <Synthesis of Alkoxysilicon Compound (A) to be Purified> [Synthesis Example 1] In a 500 mL four-neck flask, 30.09 g of monoallyl isocyanurate (manufactured by Shikoku Chemical Industry Co., Ltd.), 150.73 g of toluene, and 1.71 g of Karstedt catalyst [platinum (0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (platinum content of 2% by mass or less in xylene solution)] (manufactured by SIGMA-ALDRICH Co., Ltd.) were charged and stirred at 25° C. Then, 37.78 g of triethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise to the mixture in the flask so that the temperature of the mixture was 30° C. or less, and the mixture was heated to 100° C. after the addition and reacted for 25 hours. After the reaction, toluene and excess triethoxysilane were removed from the reaction solution using an evaporator, 303.70 g of dichloromethane was added to the crude product obtained, and the mixture was separated three times with 155.14 g of ion-exchanged water to extract the organic layer. Dichloromethane was removed from the organic layer using an evaporator, and 330.86 g of tetrahydrofuran was added to the crude product obtained to dissolve the crude product, which was stirred at 25°C for 10 minutes and then filtered to separate the filtrate and the residue. The filtrate obtained was then evaporated, and the organic layer was separated. Tetrahydrofuran was removed using a separatory evaporator, and 276.18 g of toluene was added to the resulting crude product, which was then stirred at 25°C for 10 minutes and filtered to separate the filtrate and the residue. Toluene was then removed from the residue using an evaporator to obtain the desired purified alkoxysilicon compound (A) (ICA-TEOS) as a pale yellow solid (yield 43.2%). [ka] Regarding the obtained alkoxysilicon compound (A) to be purified, 1 The compound was identified by measuring the H-NMR spectrum. The results are shown below. The solvent used for the measurement was deuterated dimethyl sulfoxide, the measurement temperature was room temperature, and the reference sample was tetramethylsilane (TMS). 1H-NMR (500MHz): 0.50~0.60ppm(m,2H), 1.10~1.15ppm(t,9H), 1.50~1.60ppm(m,2H), 3. 55~3.65ppm(t,2H), 3.48~3.52ppm(m,4H), 3.70~3.80ppm(m,6H), 11.3~11.4ppm(s,2H) Furthermore, the amount of residual Pt in a 1 wt% propylene glycol monomethyl ether (PGME) solution of the resulting purified alkoxy silicon compound (A) was measured using inductively coupled plasma mass spectrometry (ICP-MS 7500, manufactured by Agilent Technologies) and was found to be 8.2 ppm, calculated based on 100 wt% purified alkoxy silicon compound (A).

[0031] <Purification of the alkoxysilicon compound (A) to be purified using a chelating resin> The chelating resins used in the examples and comparative examples are as follows: [ka] * indicates the bond end with the resin carrier, and the resin carrier is polystyrene, cross-linked porous polystyrene, or the like. [ka] * indicates the bond end with the resin carrier, and the resin carrier is polystyrene, cross-linked porous polystyrene, or the like.

[0032] [Example 1] The alkoxy silicon-containing compound (A) obtained in Synthesis Example 1 was diluted with PGME to prepare a 1 wt% solution. 1 g of Purolite's chelating resin S914 (trade name) having a thiourea group was added to 10 g of this solution, and the mixture was stirred at room temperature for 4 hours, and then filtered to obtain a purified alkoxy silicon compound solution. The amount of adsorption of the obtained solution was measured by GC, and the amount of residual Pt was measured by inductively coupled plasma mass spectrometry (ICP-MS 7500, manufactured by Agilent Technologies). The results of measuring the amount of adsorption and the amount of residual Pt are shown in Table 1. The amount of residual Pt is shown as the value when the alkoxy silicon compound is converted to 100 wt%.

[0033] [Example 2] The same treatment was carried out using Purolite's chelating resin S920 having a thiouronium group instead of the Purolite's chelating resin used in Example 1. The results are shown in Table 1.

[0034] [Example 3] The same treatment was carried out using Muromac XMS-5418 (trade name), a chelating resin having thiouronium groups manufactured by Muromachi Chemical Co., Ltd., instead of the Purolite chelating resin used in Example 1. The results are shown in Table 1.

[0035] [Example 4] Instead of PGME, which is the dilution solvent used in Example 3, the alkoxysilicon compound (A) to be purified obtained in Synthesis Example 1 was diluted with cyclopentyl methyl ether (CPME) to prepare a 1 wt % solution, and the same treatment was carried out. The results are shown in Table 1.

[0036] [Comparative Example 1] A similar treatment was carried out using a chelating resin CRB03 (trade name) having an N-methyl-glucamine group manufactured by Mitsubishi Chemical Corporation, instead of the chelating resin manufactured by Purolite Co., Ltd. in Example 1. The amount of adsorption of the obtained solution was measured, and it was confirmed that 44% of ICA-TEOS was adsorbed by CRB03.

[0037] [Comparative Example 2] The same treatment was carried out using a chelating resin having a polyamine group, CR20 (trade name) manufactured by Mitsubishi Chemical Corporation, instead of the chelating resin manufactured by Purolite Corporation in Example 1. The adsorption amount was measured and it was confirmed that 15% of ICA-TEOS was adsorbed onto CR20.

[0038] [Comparative Example 3] A similar treatment was carried out using a chelating resin IRC748 (trade name) having an iminodiacetic acid group manufactured by Organo Corporation, instead of the chelating resin manufactured by Purolite Co., Ltd. in Example 1. The resulting solution became cloudy and subsequent treatment was not possible.

[0039] [Comparative Example 4] A similar treatment was carried out using a chelating resin IRC747UPS (trade name) having an aminophosphate group manufactured by Organo Corporation, instead of the chelating resin manufactured by Purolite Co., Ltd. in Example 1. The resulting solution became cloudy and subsequent treatment was not possible.

[0040] [Table 1]

[0041] As shown in Table 1, when the chelating resins of Examples 1 to 4 were used, platinum could be removed while suppressing the amount of alkoxy silicon compounds adsorbed to the chelating resin, whereas when the chelating resins of Comparative Examples 1 and 2 were used, the amount of alkoxy silicon compounds adsorbed to the chelating resin was large, making it impractical. Also, when the chelating resins of Comparative Examples 3 and 4 were used, the solution became cloudy and subsequent metal removal treatment could not be continued.

Claims

1. A method for purifying an alkoxysilicon compound for use in a coating film-forming composition for lithography, comprising treating an alkoxysilicon compound to be purified that contains metal impurities with a chelating resin having a functional group containing a sulfur atom and a nitrogen atom, the method comprising the steps of: The method for purifying an alkoxysilicon compound is characterized in that the alkoxysilicon compound is a compound obtained by reacting an isocyanuric acid derivative having an allyl group with an alkoxysilicon compound having a Si-H bond, and the functional group is represented by any one of the following formulas (1-1) to (1-3). 【Chemistry 1】 (In the formulas (1-1) to (1-3), * represents the bond end with the resin used as the carrier.)

2. A method for purifying an alkoxysilicon compound as described in claim 1, wherein the alkoxysilicon compound is a compound obtained by reacting an isocyanuric acid derivative having an allyl group with an alkoxysilicon compound having a Si-H bond in the presence of a transition metal catalyst.

3. 3. A method for purifying an alkoxysilicon compound according to claim 1, characterized in that the alkoxysilicon compound to be purified, which contains metal impurities, is treated with a mixture containing the chelating resin or a mixture of the chelating resin and another chelating resin.

4. The method for purifying an alkoxysilicon compound according to claim 1 or 2, characterized in that the alkoxysilicon compound to be purified containing metal impurities is treated with two or more resins selected from the group consisting of the chelating resin, a mixture containing the chelating resin, other chelating resins, and a mixture of the chelating resin and other chelating resins, one by one in turn.

5. 5. The method for purifying an alkoxysilicon compound according to claim 1, wherein the alkoxysilicon compound has a molecular weight of 5,000 or less.

6. 6. The method for purifying an alkoxysilicon compound according to claim 1, wherein the alkoxysilicon compound having a Si--H bond is a trialkoxysilane compound.

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