Method for producing aqueous solutions of purified aminosilanol compounds and aminosiloxane compounds, and etching compositions

Abstract

A method that brings an aqueous solution containing an aminosilanol compound represented by general formula (1) R1R2N-R3-SiR4 m(OH)3-m (1) (R1 and R2 represent a hydrogen atom, a C1-20 monovalent hydrocarbon group, etc., R3 represents a C1-20 divalent hydrocarbon group, R4 represents a C1-20 monovalent hydrocarbon group, and m represents an integer of 0-2.) and a condensate thereof into contact with an acidic cation exchange resin and produces an aqueous solution of a purified aminosilanol compound and aminosiloxane compound that removes metal components in the aqueous solution, the concentration of aminosilanol compound and aminosiloxane compound in the aqueous solution brought into contact with the acidic cation exchange resin being 10-70 mass%, gives an aqueous solution of a purified aminosilanol compound and aminosiloxane compound in which metal impurities contained therein are efficiently decreased.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a purified aminosilanol compound and an aqueous solution of an aminosiloxane compound, and an etching composition. [Background technology]

[0002] Aminosilanol compounds are used as surface treatment agents and water-based paints, as well as additives to etching materials to improve the etching selectivity of nitride films relative to oxide films and to prevent particle generation (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-538692 Summary of the Invention [Problem to be solved by the invention]

[0004] In semiconductor manufacturing processes, metal impurities can adversely affect electrical properties and processed shapes, so it is desirable to reduce them as much as possible. For this reason, it may be considered preferable to reduce metal impurities in the etching process as well. However, since a cleaning process is usually performed after etching, it is believed that metal impurities will be washed away in the subsequent cleaning process even if aminosilanol compounds and aminosiloxane compounds with reduced metal impurities are not used. In this regard, even in the above-mentioned Patent Document 1, purified aminosilanol compounds are not used. However, once metal impurities adhere to the surface of a semiconductor substrate, they are difficult to remove even in the cleaning process after etching. If the contaminated surface is used in subsequent processes, it may cause pattern defects, poor dielectric strength of the insulating film, etc.

[0005] On the other hand, in Patent Document 1, 1.2 wt % of an aminosilanol compound is added as an additive to the etching composition, but when the aminosilanol compound is added as a solid, it is considered to carry out purification by crystallization to remove metal impurities contained in the solid and other impurities that may cause particles. However, purification by crystallization requires dedicated crystallization equipment and equipment for crushing the crystallized solid, and if crystallization is carried out in a short period of time, there is a high possibility that impurities will not be completely removed and will be incorporated into the solid. Furthermore, when the compound is added as an aqueous solution, purification can be performed by filtration or other procedures, making purification easier than when the compound is added as a solid. However, if the concentration of the aminosilanol compound is low, a large amount of aqueous solution will be added to bring out the effectiveness of the amine component, and as a result, the large amount of water used as the solvent will dilute the entire etching agent and weaken the acidity required for etching. Therefore, it is preferable to use an aqueous solution with a high concentration.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for producing a purified aqueous solution of an aminosilanol compound and an aminosiloxane compound in which the metal impurities contained in the aqueous solution of an aminosilanol compound and an aminosiloxane compound are efficiently reduced, and an etching composition. [Means for solving the problem]

[0007] As a result of extensive investigations to achieve the above object, the present inventors discovered that metal impurities contained in an aqueous solution of an aminosilanol compound and an aminosiloxane compound can be reduced by contacting the aqueous solution containing an aminosilanol compound and an aminosiloxane compound with an acidic cation exchange resin, which is inherently unsuitable for purifying basic compounds, by a method such as passing the aqueous solution through the resin, thereby completing the present invention.

[0008] That is, the present invention is 1. The following general formula (1) R 1 R 2 NR 3 -SiR4 m (OH) 3-m (1) (In the formula, R 1 and R 2 each independently represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hydrogen atom or a heteroatom; R 1 and R 2 may be bonded to each other and to the nitrogen atom to which they are attached to form a ring, R 3 represents a substituted or unsubstituted divalent hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, and R 4 represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, and m represents an integer of 0 to 2. and an aminosiloxane compound, which is a condensate thereof, with an acidic cation exchange resin, thereby removing metal components from the aqueous solution. a method for producing a purified aqueous solution of aminosilanol compounds and aminosiloxane compounds, wherein the concentration of the aminosilanol compounds and aminosiloxane compounds in the aqueous solution to be contacted with the acidic cation exchange resin is 10 to 70 mass %; 2. The aqueous solution to be contacted with the acidic cation exchange resin further contains a compound represented by the following general formula (2): R 5 n Si(OH) 4-n (2) (In the formula, R 5 represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, and n represents an integer of 0 to 3. a method for producing an aqueous solution of a purified aminosilanol compound and an aminosiloxane compound according to claim 1, which contains a silanol compound represented by the formula: 3. An etching composition comprising an aqueous solution of an aminosilanol compound and an aminosiloxane compound, each containing less than 250 ppb of sodium, potassium and calcium, and less than 100 ppb of iron; 4. The aminosilanol compound and the aminosiloxane compound are represented by the following general formula (1): R 1 R 2 NR 3 -SiR 4 m (OH) 3-m (1) (In the formula, R 1 and R 2 each independently represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hydrogen atom or a heteroatom; R 1 and R 2 may be bonded to each other and to the nitrogen atom to which they are attached to form a ring, R 3 represents a substituted or unsubstituted divalent hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, and R 4 represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, and m represents an integer of 0 to 2. an etching composition 3, which is an aminosilanol compound represented by the formula: 5. Furthermore, the aqueous solution contains a compound represented by the following general formula (2): R 5 n Si(OH) 4-n (2) (In the formula, R 5 represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, and n represents an integer of 0 to 3. 5. The etching composition according to 3 or 4, comprising a silanol compound represented by the formula: to provide. [Effects of the Invention]

[0009] According to the present invention, aqueous solutions of purified aminosilanol compounds and aminosiloxane compounds with reduced metal impurities can be obtained. This aqueous solution with a reduced content of metal impurities is suitable as an etching composition, and by performing etching using an etching composition containing this aqueous solution, the frequency of occurrence of short circuits, breaks, etc. in patterns can be reduced. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be specifically described below. The method of the present invention for producing a purified aqueous solution of an aminosilanol compound and an aminosiloxane compound uses an acidic cation exchange resin to purify an aqueous solution containing an aminosilanol compound represented by the following general formula (1) and an aminosiloxane compound that is a condensate thereof. R 1 R 2 NR 3 -SiR 4 m (OH) 3-m (1)

[0011] In general formula (1), R 1 and R 2 are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, and more preferably 1 to 8 carbon atoms, which may contain a hydrogen atom or a heteroatom. R 1 and R 2 The monovalent hydrocarbon group may be linear, branched, or cyclic, and specific examples thereof include linear alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, and icosyl; branched alkyl groups such as isopropyl, isobutyl, sec-butyl, tert-butyl, thexyl, and 2-ethylhexyl; cyclic alkyl groups such as cyclopentyl and cyclohexyl; alkenyl groups such as vinyl, allyl, and 1-propenyl; aryl groups such as phenyl and tolyl; and aralkyl groups such as benzyl. Of these, methyl, ethyl, and n-propyl groups are more preferred.

[0012] The monovalent hydrocarbon group may contain a heteroatom selected from oxygen, nitrogen, sulfur, and silicon. Specific examples of such monovalent hydrocarbon groups include hydroxyethyl, methoxyethyl, ethoxyethyl, ethoxypropyl, glycidyl, aminomethyl, aminoethyl, mercaptomethyl, mercaptoethyl, trimethylsilyl, carboxymethyl, methylamidomethyl, methyl ethanoate, and methyl propionate groups, with hydroxyethyl, aminoethyl, and methyl ethanoate being particularly preferred. Furthermore, the monovalent hydrocarbon group may have some or all of the hydrogen atoms of the hydrocarbon group substituted with other substituents, and specific examples of other substituents include alkoxy groups having 1 to 5 carbon atoms, such as methoxy, ethoxy, and (iso)propoxy groups; halogen atoms, such as fluorine, chlorine, bromine, and iodine atoms; cyano groups; amino groups; acyl groups having 2 to 10 carbon atoms; and trialkylsilyl groups in which the alkyl group has 1 to 5 carbon atoms, with methoxy, ethoxy, and trialkylsilyl groups being particularly preferred. Also, R 1 and R 2 Specific examples of the ring having 2 to 20 carbon atoms that is formed by bonding together with the nitrogen atom to which they are bonded include a pyrrolidine ring, a piperidine ring, a piperazine ring, and a morpholine ring.

[0013] R 3 is a substituted or unsubstituted divalent hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, and more preferably 1 to 8 carbon atoms, which may contain a hydrogen atom or a heteroatom. R 3The divalent hydrocarbon group may be linear, branched, or cyclic, and specific examples thereof include linear alkylene groups such as methylene, ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, decylene, dodecylene, tetradecylene, hexadecylene, octadecylene, and icosylene; branched alkylene groups such as propylene, isobutylene, sec-butylene, and tert-butylene; cyclopropylene, cyclobutylene, and cyclohexylene; cyclic alkylene groups such as pentylene and cyclohexylene; alkenylene groups such as ethenylene, propenylene, butenylene, pentenylene, hexenylene, heptenylene, octenylene, decenylene, dodecenylene, tetradecenylene, hexadecenylene, octadecenylene and icosenylene; arylene groups such as phenylene and naphthylene; and aralkylene groups such as methylenephenylene and methylenephenylenemethylene, with a methylene group, ethylene group and trimethylene group being particularly preferred.

[0014] The divalent hydrocarbon group may contain a heteroatom selected from an oxygen atom, a nitrogen atom, a sulfur atom, or a silicon atom. Specific examples of such divalent hydrocarbon groups include methyleneoxymethylene, methyleneoxyethylene, methyleneoxytrimethylene, ethyleneoxymethylene, ethyleneoxyethylene, ethyleneoxytrimethylene, propyleneoxymethylene, trimethyleneoxyethylene, propyleneoxytrimethylene, methyleneaminomethylene, methyleneaminoethylene, methyleneaminotrimethylene, ethyleneaminomethylene, ethyleneaminoethylene, ethyleneaminotrimethylene, trimethyleneaminomethylene, trimethyleneaminoethylene, and trimethylaminoethylene. Examples include methyleneaminotrimethylene, methylenethiomethylene, methylenethioethylene, methylenethiotrimethylene, ethylenethiomethylene, ethylenethioethylene, ethylenethiotrimethylene, trimethylenethiomethylene, trimethylenethioethylene, trimethylenethiopropylene, methylenedimethylsilamethylene, ethylenedimethylsilaethylene, and ethylenedimethylsilatrimethylene groups, and particularly preferred are an ethyleneaminoethylene group, an ethyleneaminotrimethylene group, a trimethyleneaminoethylene group, and a trimethyleneaminotrimethylene group. In addition, the divalent hydrocarbon group may have some or all of the hydrogen atoms of the hydrocarbon group substituted with other substituents. Specific examples of other substituents include R 1 and R 2 Examples of the substituents include the same as those exemplified above.

[0015] R 4 is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, and more preferably 1 to 8 carbon atoms. R 4 The monovalent hydrocarbon group may be linear, branched, or cyclic, and specific examples thereof include R 1 and R 2 Examples of the substituents include the same as those exemplified above. m is an integer of 0 to 2, ie, 0, 1 or 2.

[0016] Specific examples of the aminosilanol compound represented by general formula (1) include aminomethylsilanetriol, aminomethylmethylsilanediol, aminomethyldimethylsilanol, aminoethylsilanetriol, aminoethylmethylsilanediol, aminoethyldimethylsilanol, 3-aminopropylsilanetriol, 3-aminopropylmethylsilanediol, 3-aminopropyldimethylsilanol, 3-(N-methylamino)propylsilanetriol, 3-(N-methylamino)propylmethylsilanediol, 3-(N-methylamino)propyldimethylsilanol, 3-(N-dimethylamino)propylsilanetriol, 3-(N-dimethylamino)propylmethylsilanediol, 3-(N-dimethylamino)propyldimethylsilanol, N-(2-aminoethyl)-3-aminopropylsilanol, Examples thereof include silanetriol, N-(2-aminoethyl)-3-aminopropylmethylsilanediol, N-(2-aminoethyl)-3-aminopropyldimethylsilanol, 3-pyrrolidinylpropylsilanetriol, 3-pyrrolidinylpropylmethylsilanediol, 3-pyrrolidinylpropyldimethylsilanol, 3-piperidinylpropylsilanetriol, 3-piperidinylpropylmethylsilanediol, 3-piperidinylpropyldimethylsilanol, 3-(1-piperazinyl)propylsilanetriol, 3-(1-piperazinyl)propylmethylsilanediol, 3-(1-piperazinyl)propyldimethylsilanol, 3-(4-morpholinyl)propylsilanetriol, 3-(4-morpholinyl)propylmethylsilanediol, and 3-(4-morpholinyl)propyldimethylsilanol. Among these, 3-aminopropylsilanetriol and N-(2-aminoethyl)-3-aminopropylsilanetriol are particularly preferred.

[0017] The aminosilanol compound is obtained, for example, by a hydrolysis reaction between an aminoalkylalkoxysilane and water, and the aminosilanol compound is then subjected to dehydration condensation to form an aminosiloxane compound. The aminosilanol compound and aminosiloxane compound contained in the aqueous solution containing the aminosilanol compound and aminosiloxane compound may be derived from one type of aminosilane or from multiple types.

[0018] The aqueous solution containing the aminosilanol compound and aminosiloxane compound used in the present invention may further contain a silanol compound represented by the following general formula (2) and a siloxane compound that is a condensate thereof. R 5 n Si(OH) 4-n (2)

[0019] In general formula (2), R 5 is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, and more preferably 1 to 8 carbon atoms. R 5 The monovalent hydrocarbon group may be linear, branched, or cyclic, and specific examples thereof include R 1 and R 2 Examples of the substituents include the same as those exemplified above. n is an integer of 0 to 3, ie, 0, 1, 2, or 3.

[0020] Specific examples of the silanol compound represented by general formula (2) include orthosilicic acid, methyl silanetriol, dimethyl silanediol, trimethyl silanol, ethyl silanetriol, diethyl disilanediol, triethyl silanol, propyl silanetriol, dipropyl silanediol, tripropyl silanol, isopropyl silanetriol, diisopropyl silanediol, triisopropyl silanol, butyl silanetriol, dibutyl silanediol, tributyl silanol, (sec-butyl) silanetriol, and di(sec-butyl) silane. Examples include diol, tri(sec-butyl)silanol, (tert-butyl)silanetriol, di(tert-butyl)silanediol, tri(tert-butyl)silanol, pentylsilanetriol, dipentylsilanediol, tripentylsilanol, hexylsilanetriol, dihexylsilanediol, trihexylsilanol, cyclopentylsilanetriol, dicyclopentylsilanediol, tricyclopentylsilanol, cyclohexylsilanetriol, dicyclohexylsilanediol, tricyclohexylsilanol, etc. Among these, orthosilicic acid, methylsilanetriol, dimethylsilanediol, trimethylsilanol, ethylsilanetriol, diethyldisilanediol, and triethylsilanol are particularly preferred.

[0021] The silanol compound is obtained, for example, by a hydrolysis reaction of alkylchlorosilane or alkylalkoxysilane with water, and the silanol compound is then subjected to dehydration condensation to form a siloxane compound. The silanol compound and siloxane compound contained in the aqueous solution containing the aminosilanol compound and the aminosiloxane compound may be derived from one type of silane or from multiple types of silanes.In addition, the aqueous solution may contain condensates formed by condensation of the aminosilanol compound and the aminosiloxane compound with the silanol compound and the siloxane compound.

[0022] The production method of the present invention may contain a solvent other than water, and examples of the solvent include alcohol solvents such as methanol and ethanol, ether solvents such as tetrahydrofuran and dioxane, ester solvents such as ethyl acetate and butyl acetate, and aprotic polar solvents such as acetonitrile and N,N-diethylformamide. These solvents may be used alone or in combination. The amount of the organic solvent used is 0% by mass or more and less than 50% by mass, preferably 10 to 40% by mass, based on the total amount of the solvent.

[0023] Ion exchange resins are made up of polymeric molecular chains with a network structure, each containing a group that releases the ion to be exchanged. Ion exchange resins are widely used as a method for purifying compounds. By contacting a liquid with the ion exchange resin, the ions to be removed from the liquid are exchanged for ions that have already been adsorbed on the resin, allowing the ions to be removed from the liquid while still adsorbed on the resin. Ion exchange resins are broadly classified into acidic cation exchange resins and basic anion exchange resins depending on the nature of the ion exchange groups they contain. Functional groups contained in acidic cation exchange resins include sulfonic acid groups, carboxylic acid groups, phosphonic acid groups, and aminophosphate groups, while functional groups contained in basic anion exchange resins include amino groups and quaternary ammonium groups.

[0024] Acidic cation exchange resins are usually used to remove metal impurities. In terms of the efficiency of removing metal impurities, the adsorption between the ion exchange resin and the substance is in equilibrium. Therefore, for example, when removing metal impurities from an amine aqueous solution, the higher the amine compound concentration, the more frequently the abundant basic amine components are adsorbed onto the acidic ion exchange resin surface. In this way, under conditions where the amine components are already adsorbed onto most of the ion exchange resin surface, the probability of trace metal impurities being adsorbed is low, and the efficiency of removing metal impurities is poor. Therefore, the higher the aqueous solution concentration, the less suitable it is to use acidic ion exchange resins as a method for removing trace metal components from aqueous solutions of aminosilanol compounds and aminosiloxane compounds. Furthermore, while low-molecular-weight monomers can be easily desorbed from the surface of an ion-exchange resin, in the case of aqueous solutions containing polymers such as aminosiloxane compounds, the aminosiloxane compounds themselves have a complex structure and contain many amino groups, so a single molecule is adsorbed to multiple acidic functional groups over a wide area, making it difficult for them to desorb from the surface of the ion-exchange resin. This makes it thought that removing metal impurities would not be easy. For these reasons, acidic cation exchange resins have traditionally been thought to be unsuitable for purifying basic compounds. However, it has been unexpectedly discovered that when used to purify aminosilanol compounds and aminosiloxane compounds, metal impurities can be reduced.

[0025] There are no restrictions on the ion exchange groups present in the acidic cation exchange resin used in the present invention, but sulfonic acid groups, carboxylic acid groups, phosphonic acid groups, and aminophosphate groups are preferred. There are no restrictions on the shape of the cation exchange resin, but filter (disk), granular, column, or cartridge shapes are preferred because of their ease of availability.

[0026] Examples of methods for contacting an aqueous solution of an aminosilanol compound and an aminosiloxane compound with an acidic cation exchange resin include a liquid-passing method in which the aqueous solution is passed through the acidic cation exchange resin itself or a column or filter packed with the resin, and a method in which the acidic cation exchange resin is added to the aqueous solution, followed by stirring and filtering, and the like. The liquid-passing method is preferred. When an aqueous solution containing an aminosilanol compound and an aminosiloxane compound is passed through an acidic cation exchange resin, there is no limitation on the speed of the passage. In the case of a 47 mmφ filter, the speed is preferably 1 to 100 ml / min, more preferably 3 to 50 ml / min, and even more preferably 5 to 25 ml / min. There is no restriction on the pressure during the liquid passage, but atmospheric pressure is preferred for ease of implementation.

[0027] In the present invention, the concentration of the purified aminosilanol compound and aminosiloxane compound in the aqueous solution that is brought into contact with the acidic cation exchange resin is 10 to 70% by mass, preferably 20 to 60% by mass, and more preferably 25 to 55% by mass. If the concentration is less than 10% by mass, the amount of aqueous solution will be large due to the low concentration, which is economically inefficient when considering the treatment time and treatment area required during liquid passage, etc. On the other hand, if the concentration exceeds 70% by mass, the viscosity of the aqueous solution will increase, making the treatment itself, such as liquid passage, difficult.

[0028] When the aqueous solution contains a silanol compound and a siloxane compound, there are no particular restrictions on their concentrations, but the total concentration of the aminosilanol compound and the aminosiloxane compound is preferably 10 to 70 mass %, more preferably 20 to 60 mass %, and even more preferably 25 to 55 mass %.

[0029] The etching composition of the present invention comprises an aqueous solution of an aminosilanol compound and an aminosiloxane compound, each containing less than 250 ppb of sodium, potassium, and calcium, preferably 220 ppb or less, and more preferably 200 ppb or less, and having an iron content of less than 100 ppb, preferably 80 ppb or less, and more preferably 50 ppb or less. As the aqueous solution of the aminosilanol compound and aminosiloxane compound with a low metal content, it is preferable to use an aqueous solution containing the aminosilanol compound represented by the above formula (1) and an aminosiloxane compound that is a condensate thereof, in which the metal contents have been reduced by a method using the above acidic cation exchange resin.

[0030] The etching composition of the present invention preferably contains an aqueous solution of the purified aminosilanol compound and aminosiloxane compound having a reduced metal content as described above, and an acidic substance such as hydrofluoric acid or phosphoric acid that is typically used in acidic etching compositions.

[0031] There are no restrictions on the content of the aqueous solution of the aminosilanol compound and the aminosiloxane compound in the etching composition of the present invention, but from the viewpoint of improving the etching selectivity of a nitride film relative to an oxide film and preventing particle generation, the content is preferably 0.001 to 50 mass %, more preferably 0.005 to 30 mass %, and even more preferably 0.01 to 10 mass %, based on the total mass of the etching composition. As mentioned above, the concentration of the aminosilanol compound and aminosiloxane compound in the aqueous solution is 10 to 70% by mass, preferably 20 to 60% by mass, and more preferably 25 to 55% by mass.

[0032] The aqueous solution of the aminosilanol compound and aminosiloxane compound used in the etching composition may further contain a silanol compound represented by the general formula (2) above and a siloxane compound that is a condensate thereof. In this case, too, there are no particular restrictions on the concentrations of the silanol compound and the siloxane compound in the aqueous solution, but the total concentration of the aminosilanol compound and the aminosiloxane compound is preferably 10 to 70 mass%, more preferably 20 to 60 mass%, and even more preferably 25 to 55 mass%. [Example]

[0033] 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.

[0034] [1] Preparation of an aqueous solution containing an aminosilanol compound and an aminosiloxane compound [Synthesis Example 1] A 5 L four-neck glass flask was fitted with a fractionating head equipped with a reflux condenser, a thermometer, and a stirring blade, and the inside of the flask was purged with nitrogen. 3 kg of ion-exchanged water was charged and the temperature was adjusted to 20-30°C. 1 kg of 3-aminopropyltriethoxysilane was added dropwise to the flask. The ethanol produced by hydrolysis and excess water were then distilled off, resulting in a 9.5 mm viscosity. 2 An aqueous solution containing an aminosiloxane compound with a concentration of 3-aminopropylsilanetriol and its condensate of 33.6 mass % was obtained, the aqueous solution having a viscosity of 1.109, a specific gravity of 1.109, an amine equivalent of 345 g / mol, and a viscosity of 1.109.

[0035] [Synthesis Example 2] A 5 L four-neck glass flask was fitted with a fractionating head equipped with a reflux condenser, a thermometer, and a stirring blade, and the inside of the flask was purged with nitrogen. 3 kg of ion-exchanged water was charged and the temperature was adjusted to 20-30°C. 1 kg of 3-aminopropyltriethoxysilane was added dropwise to the flask. The ethanol produced by hydrolysis and excess water were then distilled off, resulting in a filtrate with a viscosity of 52.9 mm. 2 An aqueous solution containing an aminosiloxane compound with a concentration of 44.4 mass % of 3-aminopropylsilanetriol and its condensate was obtained, the aqueous solution having a viscosity of 1.154, a specific gravity of 1.154, an amine equivalent of 261 g / mol, and a viscosity of 1.154.

[0036] [Synthesis Example 3] A 5 L four-neck glass flask was fitted with a fractionating head equipped with a reflux condenser, a thermometer, and a stirring blade, and the inside of the flask was purged with nitrogen. 1.5 kg of ion-exchanged water was charged and the temperature was adjusted to 20-30°C. 0.3 kg of N-2-(aminoethyl)-3-aminopropyltrimethoxysilane and 0.1 kg of tetraethoxysilane were added dropwise. The alcohol produced by hydrolysis and excess water were then distilled off to obtain a liquid with a viscosity of 9.2 mm. 2An aqueous solution containing an aminosiloxane compound was obtained, with a concentration of 30.2 mass% of a composition consisting of N-2-(aminoethyl)-3-aminopropylsilanetriol and its condensates, orthosilicic acid and its condensates, and a condensate of N-2-(aminoethyl)-3-aminopropylsilanetriol and orthosilicic acid, with a viscosity of 1.100 / s, specific gravity of 1.100, and amine equivalent of 254 g / mol.

[0037] [2] Preparation of aqueous solutions of purified aminosilanol compounds and aminosiloxane compounds [Example 1-1] Two 250 mL polypropylene (PP) bottles were prepared, and 150 g of the aqueous solution obtained in Synthesis Example 1 was filled into one bottle. An acidic cation exchange resin (SCP, 3M Japan, φ47 mm disk type) through which the aqueous solution was passed was attached to a polytetrafluoroethylene (PTFE) filter holder. The aqueous solution was passed through the acidic cation exchange resin at a flow rate of 15 g / min using a Smoothflow pump (Takumina) and PTFE tubing, and collected in the other 250 mL PP bottle, which served as the receiver. After collection, the PP bottle on the receiver side was replaced with the empty PP bottle on the flow side, and the aqueous solution collected in the PP bottle on the receiver side was again passed through the acidic cation exchange resin using the pump. This liquid-passing procedure was repeated 10 times, and an aqueous solution containing purified 3-aminopropylsilanetriol and its condensate, an aminosiloxane compound, was collected. Thereafter, the contents of the main metal impurities contained in 142.3 g of the recovered aqueous solution were measured using an inductively coupled plasma mass spectrometer (Agilent 7700x ICP-MS, manufactured by Agilent Technologies). The results are shown in Table 1.

[0038] [Table 1]

[0039] As shown in Table 1, it can be seen that the metal impurities contained in the aqueous solution obtained in Synthesis Example 1 can be reduced by passing the solution through an acidic cation exchange resin. In particular, the contents of Na, which is said to be likely to cause poor voltage resistance of oxide films, and Ca, which may deteriorate the insulation resistance of gate oxide films, were significantly reduced after filtration. The detection limit for each metal impurity was 10 ppb. The contents of Cr, Mn, Ni, Co, Cu, Ag, In, Ta, and Pb measured at the same time were all below the detection limit of 10 ppb before passing the solution through the acidic cation exchange resin. Therefore, no measurement was performed after passing the solution through the resin.

[0040] [Example 1-2] Two 250 mL PP bottles were prepared, and 150 g of the aqueous solution obtained in Synthesis Example 2 was filled into one of the bottles. Since the viscosity was higher than in Synthesis Example 1, the same operation as in Example 1-1 was carried out, except that the liquid flow rate was changed to 10 g / min, and an aqueous solution containing purified 3-aminopropylsilanetriol and its condensate, an aminosiloxane compound, was recovered. Thereafter, the main metal impurities contained in 147.0 g of the recovered aqueous solution were measured in the same manner as in Example 1-1. The results are shown in Table 2.

[0041] [Table 2]

[0042] As shown in Table 2, even when a highly viscous aminosilanol compound and its condensate, an aminosiloxane compound, were used, passing the aqueous solution obtained in Synthesis Example 2 through an acidic cation exchange resin, as in Example 1-1, reduced the metal impurities contained in the aqueous solution. Furthermore, slowing the treatment speed due to the viscosity extended the contact time of the aqueous solution with the ion exchange resin, and the content of potassium, which is likely to cause poor pressure resistance of the oxide film, was also significantly reduced after filtration. The detection limit for each metal impurity was 10 ppb. The contents of Cr, Mn, Ni, Co, Cu, Ag, In, Ta, and Pb measured at the same time were all below the detection limit of 10 ppb before passing the solution through the acidic cation exchange resin. Therefore, no measurement was performed after passing the solution through the resin.

[0043] [Examples 1-3] Two 250 mL PP bottles were prepared, and the same operation as in Example 1-1 was carried out except that 150 g of the aqueous solution obtained in Synthesis Example 3 was filled into one of the bottles, thereby recovering an aqueous solution containing a composition composed of purified N-2-(aminoethyl)-3-aminopropylsilanetriol and its condensates, orthosilicic acid and its acid condensates, and a condensate of N-2-(aminoethyl)-3-aminopropylsilanetriol and orthosilicic acid. Thereafter, the main metal impurities contained in 147.5 g of the recovered aqueous solution were measured in the same manner as in Example 1-1. The results are shown in Table 3.

[0044] [Table 3]

[0045] The composition of Synthesis Example 3, which is composed of N-2-(aminoethyl)-3-aminopropylsilanetriol and its condensates, orthosilicic acid and its condensates, and a condensate of N-2-(aminoethyl)-3-aminopropylsilanetriol and orthosilicic acid, contains two nitrogen atoms per aminosilane molecule, which makes it more susceptible to adsorption by an acidic cation exchange resin. However, as shown in Table 3, by passing the aqueous solution obtained in Synthesis Example 3 through an acidic cation exchange resin, the metal impurities contained in the aqueous solution can be reduced. The detection limit for each metal impurity was 10 ppb. The contents of Cr, Mn, Ni, Co, Cu, Ag, In, Ta, and Pb measured at the same time were all below the detection limit of 10 ppb before passing the solution through the acidic cation exchange resin. Therefore, no measurement was performed after passing the solution through the resin.

[0046] [3] Preparation of etching composition and etching treatment [Example 2-1] An etching composition containing 3.0 mass% of the aqueous solution obtained in Example 1-1 (1.0 mass% of the aminosiloxane compound component, which is 3-aminopropylsilanetriol and its condensate) and 97.0 mass% of an 85 mass% aqueous solution of phosphoric acid was used to etch a nitride film formed on a silicon wafer substrate at 155°C. As in the case of the aqueous solution obtained in Example 1-1, the amount of metal impurities on the surface of the silicon wafer substrate after cleaning was less than that of the etching composition that had not been passed through the acidic cation exchange resin.

Claims

1. The following general formula (1) R 1 R 2 N-R 3 -SiR 4 m (OH) 3-m (1) (In the formula, R 1 and R 2 each independently represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hydrogen atom or a heteroatom; R 1 and R 2 may be bonded to each other and to the nitrogen atom to which they are attached to form a ring, R 3 represents a substituted or unsubstituted divalent hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, R 4 represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, and m represents an integer of 0 to 2. and an aminosiloxane compound, which is a condensate thereof, with an acidic cation exchange resin, thereby removing metal components from the aqueous solution. The method for producing a purified aqueous solution of aminosilanol compounds and aminosiloxane compounds is such that the concentration of the aminosilanol compounds and aminosiloxane compounds in the aqueous solution that is brought into contact with the acidic cation exchange resin is 10 to 70 mass %.

2. The aqueous solution to be contacted with the acidic cation exchange resin further contains a compound represented by the following general formula (2): R 5 n Si (O) 4-n (2) (In the formula, R 5 represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, and n represents an integer of 0 to 3.

2. A method for producing an aqueous solution of a purified aminosilanol compound and an aminosiloxane compound according to claim 1, which contains a silanol compound represented by the following formula:

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