JP2008239492A - Method for producing high purity borazine compound, and borazine compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a high purity borazine compound containing a low level of metallic elements as impurities. <P>SOLUTION: The method for producing a high purity borazine compound comprises a step of synthesizing a borazine compound represented by chemical formula (1) (wherein Rs are mutually independently selected from the group consisting of a hydrogen atom, an alkyl group and a cycloalkyl group), and a step of allowing the resulting borazine compound into contact with a metal removing agent. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a borazine compound. The borazine compound is used, for example, to form an interlayer insulating film for semiconductor, a barrier metal layer, and an etch stopper layer.

  As the performance of information equipment increases, LSI design rules become finer year by year. In the manufacture of LSIs with fine design rules, the materials that make up LSIs must also have high performance and function on fine LSIs.

  For example, regarding materials used for interlayer insulating films in LSIs, a high dielectric constant causes signal delay. In a fine LSI, the influence of this signal delay is particularly great. For this reason, development of a new low dielectric material that can be used as an interlayer insulating film has been desired. Further, in order to be used as an interlayer insulating film, it is necessary not only to have a low dielectric constant but also to be excellent in characteristics such as moisture resistance, heat resistance and mechanical strength.

  As a response to such a demand, borazine compounds having a borazine ring skeleton in the molecule have been proposed (see, for example, Patent Document 1 and Patent Document 2). Since a borazine compound having a borazine ring skeleton has a low molecular polarizability, the formed film has a low dielectric constant. In addition, the formed film is excellent in heat resistance.

As a method for producing a borazine compound, a method is known in which an alkali borohydride (for example, sodium borohydride) and an amine salt (for example, methylamine hydrochloride) are reacted in a solvent (Patent Document 3). In addition, an alkyl borazine compound in which a boron moiety is substituted with an alkyl group is obtained by using a halogenated borazine compound such as B, B ′, B ″ -trichloro-N, N ′, N ″ -trialkylborazine as a starting material. It can be synthesized by replacing the chlorine atom of the compound with an alkyl group using a Grignard reagent (see, for example, Non-Patent Document 1).
JP 2000-340689 A JP 2003-119289 A JP 2006-327964 A D. T.A. HAWORTH and L.H. F. HOHNSTEDT, J.A. Am. Chem. Soc. , 82, 3860 (1960)

  By the way, when the borazine compound obtained by the above reaction is analyzed, the compound contains a metal element as an impurity, and the purity of the borazine compound is lowered. Such a decrease in the purity of the borazine compound has a problem that it ultimately causes a decrease in performance of a semiconductor interlayer insulating film manufactured using the borazine compound.

  Therefore, an object of the present invention is to provide means for producing a high-purity borazine compound with a low content of metal elements as impurities.

  The method for producing a borazine compound of the present invention for solving the above-mentioned problem is represented by the chemical formula 1:

(In the above formula, R is independently selected from the group consisting of a hydrogen atom, an alkyl group and a cycloalkyl group) and contacting the borazine compound with a metal remover Including stages.

  According to the present invention, a high-purity borazine compound can be produced with a low content of metal elements as impurities.

  The present invention is represented by chemical formula 1:

(In the above formula, R is independently selected from the group consisting of a hydrogen atom, an alkyl group and a cycloalkyl group) and contacting the borazine compound with a metal remover A process for producing a borazine compound.

  Examples of the compound represented by the above formula include, but are not limited to, borazine, trialkylborazine and hexaalkylborazine. Hereinafter, the production method of the present invention will be described in detail.

1. Method for producing borazine and trialkylborazine compound (first embodiment)
First, in the synthesis step of a borazine compound, a borohydride metal salt and (R ₁ NH ₃ ) _m X ₁ (R ₁ is a hydrogen atom, an alkyl group or a cycloalkyl group, and X ₁ is a sulfate group or a halogen atom. And m is 2 when X ₁ is a sulfuric acid group, and m is ₁ when X ₁ is a halogen atom). A compound is synthesized.

The metal atom of the borohydride metal salt is not particularly limited. This is because each metal atom can be sufficiently removed at the stage of removing the metal described later. Examples of the metal atoms include lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, radium, zirconium, hafnium, aluminum, lanthanum, scandium, europium, iron, nickel, chromium, and the like. Preferably monovalent metal atoms (alkali metal atoms, ie lithium, sodium, potassium, rubidium, cesium) or divalent metal atoms (beryllium, magnesium, and alkaline earth metal atoms, ie calcium, strontium, barium, radium) ). When the metal atom is an element in such a range, the borohydride metal salt is an alkali metal borohydride salt (ABH ₄ (A is a monovalent metal atom)) or an alkaline earth metal borohydride salt. (M (BH ₄ ) ₂ (M is a divalent metal atom)). More preferred is sodium, lithium or calcium from the viewpoint of availability.

On the other hand, in the amine salt ((R ₁ NH ₃ ) _m X ₁ ), R ₁ is a hydrogen atom, an alkyl group or a cycloalkyl group, and X ₁ is a sulfate group or a halogen atom. When X ₁ is a sulfate group, m is 2, and when X ₁ is a halogen atom, m is 1. The halogen atom is preferably a chlorine atom. When m = 2, R ₁ may be the same or different, but R ₁ is preferably the same considering the yield of the synthesis reaction and ease of handling. The alkyl group may be linear or branched. Although carbon number which an alkyl group has is not specifically limited, Preferably it is 1-10 pieces, More preferably, it is 1-8 pieces, More preferably, it is 1-4 pieces, Especially preferably, it is one piece. Examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl, iso-propyl, butyl, iso-butyl, sec-butyl, tert-butyl, pentyl , Iso-pentyl group, 2-methylbutyl group, neo-pentyl group, 1,2-dimethylpropyl group, 1-ethylpropyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group and the like. Although carbon number which a cycloalkyl group has is not specifically limited, Preferably it is 3-8, More preferably, it is 4-7, More preferably, it is 5-6. Examples of cycloalkyl groups include, but are not limited to, cyclopropyl groups, cyclobutyl groups, cyclopentyl groups, cyclohexyl groups, and the like. Examples of the amine salt include, but are not limited to, ammonium chloride (NH ₄ Cl), monomethylamine hydrochloride (CH ₃ NH ₃ Cl), monoethylamine hydrochloride (CH ₃ CH ₂ NH ₃ Cl), monomethylamine Hydrobromide (CH ₃ NH ₃ Br), monoethylamine hydrofluoride (CH ₃ CH ₂ NH ₃ F), ammonium sulfate ((NH ₄ ) ₂ SO ₄ ), monomethylamine sulfate ((CH ₃ NH _{3) 2} SO _4), and the like.

What is necessary is just to select the kind of borohydride metal salt and amine salt as a synthesis raw material according to the structure of the borazine compound to synthesize | combine. For example, when N, N ′, N ″ -methylborazine in which a methyl group is bonded to three nitrogen atoms constituting a borazine ring, R ₁ such as monomethylamine hydrochloride is used as an amine salt. An amine salt that is a methyl group may be used.

  The mixing ratio of the borohydride metal salt and the amine salt is not particularly limited, but when the amount of amine salt used is 1 mol, the amount of alkali borohydride used may be 1 to 1.5 mol. preferable.

  The solvent for synthesis is not particularly limited, and examples thereof include tetrahydrofuran, monoethylene glycol dimethyl ether (monoglyme), diethylene glycol dimethyl ether (diglyme), triethylene glycol dimethyl ether (triglyme), and tetraethylene glycol dimethyl ether (tetraglyme). .

  The reaction conditions between the borohydride metal salt and the amine salt are not particularly limited. The reaction temperature is preferably room temperature (generally 1 to 40 ° C) to 220 ° C, more preferably 50 to 200 ° C, and still more preferably 100 to 170 ° C. When the reaction is performed within the above range, the amount of hydrogen generation can be easily controlled. The reaction temperature can be measured using a temperature sensor such as a K thermocouple.

The borazine compound in the 1st form of this invention is a compound represented by following Chemical formula 2 or 3. In the formula, since R ₁ is as described for the amine salt, the description is omitted here. Each R in the borazine compound obtained may be the same, partly the same or all different. Examples of borazine compounds include borazine, N, N ′, N ″ -trimethylborazine, N, N ′, N ″ -triethylborazine, N, N ′, N ″ -tri (n-propyl) borazine, N, N ′, N ″ -tri (iso-propyl) borazine, N, N ′, N ″ -tri (n-butyl) borazine, N, N ′, N ″ -tri (sec-butyl) borazine, N, N ′ , N ″ -tri (iso-butyl) borazine, N, N ′, N ″ -tri (tert-butyl) borazine, N, N ′, N ″ -tri (1-methylbutyl) borazine, N, N ′, N "-Tri (2-methylbutyl) borazine, N, N ', N" -tri (neo-pentyl) borazine, N, N', N "-tri (1,2-dimethylpropyl) borazine, N, N ', N ″ -tri (1-ethylpropyl) borazine, N, N ′, N ″ -tri ( -Hexyl) borazine and N, N ', N "-tricyclohexylborazine and the like, and N, N'-dimethyl-N" -ethylborazine, N, N'-diethyl-N "-methylborazine, N, N'- Examples include dimethyl-N ″ -propylborazine. In consideration of the stability of the produced borazine compound such as water resistance, the borazine compound is N, N ′, N ″ -trialkylborazine (the three alkyl groups in one molecule may be the same or different. Preferably).

  For reference, chemical formulas representing borazine (Chemical Formula 2) and trialkylborazine compounds (Chemical Formula 3) are listed below.

2. Method for producing hexaalkylborazine compound (second embodiment)
First, a halogenated borazine compound represented by the following chemical formula 4 used as a raw material is prepared.

In the above formula, R ₂ is an alkyl group. In the above chemical formula 4, R ₂ may be the same or different. Considering the yield of the synthesis reaction and ease of handling, R ₂ is preferably the same alkyl group. Examples of halogenated borazine compounds include B, B ′, B ″ -trichloro-N, N ′, N ″ -trimethylborazine, B, B ′, B ″ -trichloro-N, N ′, N ″ -triethylborazine, B , B ′, B ″ -trichloro-N, N ′, N ″ -tri (n-propyl) borazine, B, B ′, B ″ -trichloro-N, N ′, N ″ -tri (iso-propyl) borazine B, B ′, B ″ -trichloro-N, N ′, N ″ -tri (n-butyl) borazine, B, B ′, B ″ -trichloro-N, N ′, N ″ -tri (sec-butyl) ) Borazine, B, B ′, B ″ -trichloro-N, N ′, N ″ -tri (iso-butyl) borazine, B, B ′, B ″ -trichloro-N, N ′, N ″ -tri (tert -Butyl) borazine, B, B ', B "-trichloro-N, N', N" -tri (1-methylbutyl) borazi B, B ′, B ″ -trichloro-N, N ′, N ″ -tri (2-methylbutyl) borazine, B, B ′, B ″ -trichloro-N, N ′, N ″ -tri (neo-pentyl) ) Borazine, B, B ', B "-trichloro-N, N', N" -tri (1,2-dimethylpropyl) borazine, B, B ', B "-trichloro-N, N', N"- Tri (1-ethylpropyl) borazine, B, B ′, B ″ -trichloro-N, N ′, N ″ -tri (n-hexyl) borazine, B, B ′, B ″ -trichloro-N, N ′, N "-tricyclohexylborazine is mentioned. Also, B, B ′, B ″ -trifluoro-N, N ′, N ″ -trimethylborazine, B, B ′, B ″ -tribromo-N, N ′, N ″ -trimethylborazine, B, B ′, B ″ -monochlorodifluoro-N, N ′, N ″ -trimethylborazine may be substituted with a halogen element other than chlorine (Cl).

The method for obtaining the halogenated borazine compound is not particularly limited. When synthesizing a halogenated borazine compound, known knowledge can be referred to as appropriate. For example, D.C. T.A. The synthesis method described in HAWORTH, Inorganic Syntheses, 10, 43 (1971) may be employed. If synthesized by itself, for example, boron trichloride (BCl ₃ ) and an amine salt ((R ₃ NH ₃ ) _n X ₂ ) are reacted. The reaction between boron trichloride and the amine salt is preferably performed by adding boron trichloride to the amine salt suspended in a solvent. As the solvent, o-xylene, m-xylene, p-xylene, monochlorobenzene, o-dichlorobenzene, m-dichlorobenzene and the like can be used. The atmosphere around the reaction solution is not particularly limited, but the atmosphere around the reaction solution is preferably replaced with an inert gas such as nitrogen or argon.

In the amine salt, R ₃ is an alkyl group. The alkyl group may be linear, branched or cyclic. Although carbon number which an alkyl group has is not specifically limited, Preferably it is 1-10 pieces, More preferably, it is 1-8 pieces, More preferably, it is 1-4 pieces, Especially preferably, it is one piece. Specific examples of the alkyl group include methyl group, ethyl group, propyl group, iso-propyl group, butyl group, iso-butyl group, s-butyl group, t-butyl group, pentyl group, iso-pentyl group, 2- Examples include methylbutyl group, neo-pentyl group, 1,2-dimethylpropyl group, 1-ethylpropyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, cyclopropyl group, cyclopentyl group, and cyclohexyl group. . Alkyl groups other than these may be used. Since X ₂ and n are the same as X ₁ and m in the first embodiment, description thereof is omitted here.

  The prepared halogenated borazine compound is used for the reaction with the Grignard reagent, and as a result, an alkyl borazine compound represented by the following chemical formula 5 is synthesized. Since the reaction of substituting the halogen atom of the halogenated borazine compound with an alkyl group by the reaction between the halogenated borazine compound and the Grignard reagent is a known reaction as disclosed in the above non-patent literature, Briefly described.

A Grignard reaction caused by a Grignard reagent typified by R ₄ MgX ₃ (R ₄ represents an alkyl group, and X ₃ represents a halogen atom) is a form in which a halogen atom contained in a given compound is converted to an alkyl contained in the Grignard reagent. Substitute with group. Regarding the halogenated borazine compound, the halogen atom directly bonded to boron is substituted with an alkyl group contained in the Grignard reagent.

As the Grignard reagent, various Grignard reagents such as CH ₃ MgI, CH ₃ CH ₂ MgBr, and CH ₃ CH ₂ CH ₂ MgI can be used. Of course, the Grignard reagent is not limited to these.

The reaction conditions for the Grignard reagent and the halogenated borazine compound are not particularly limited. For example, a predetermined halogenated borazine compound and diethyl ether as a solvent are supplied to the reaction vessel in a nitrogen atmosphere. While stirring the reaction solution, CH ₃ MgI as a Grignard reagent is gradually added dropwise to the reaction solution. An amount of Grignard reagent slightly larger than the theoretical amount is added dropwise, and the reaction solution is stirred for another hour.

  The alkylborazine compound to be produced has a structure represented by the following chemical formula 5. In the second embodiment of the present application, the “alkyl borazine compound” means a compound represented by the chemical formula 5 unless otherwise specified.

In the above formula, R ₂ is an alkyl group. R ₂ in the alkyl borazine compound represented by the above formula may be the same or different. R ₂ is a group derived from R ₂ in Chemical Formula 4. Since R ₂ is as described for R _{2 in} Chemical Formula 4, description thereof is omitted here.

R ₃ is an alkyl group derived from the Grignard reagent. When the Grignard reagent is represented by R ₄ MgX ₃ , R ₃ is derived from R ₄ .

  The structure of such a hexaalkylborazine compound is not particularly limited. Specific examples include hexamethylborazine, hexaethylborazine, hexa (n-propyl) borazine, hexa (iso-propyl) borazine, and hexa (n-butyl). Borazine, hexa (sec-butyl) borazine, hexa (iso-butyl) borazine, hexa (tert-butyl) borazine, hexa (1-methylbutyl) borazine, hexa (2-methylbutyl) borazine, hexa (neo-pentyl) borazine, Hexa (1,2-dimethylpropyl) borazine, hexa (1-ethylpropyl) borazine, hexa (n-hexyl) borazine, hexacyclohexylborazine, B, B ′, B ″ -trimethyl-N, N ′, N ″ — Triethylborazine, B, B ', B "-trime Ru-N, N ′, N ″ -tri (n-propyl) borazine, B, B ′, B ″ -trimethyl-N, N ′, N ″ -tri (iso-propyl) borazine, B, B ′, B "-Triethyl-N, N ', N" -trimethylborazine, B, B', B "-trimethyl-N, N ', N" -tri (n-propyl) borazine, B, B', B "-trimethyl -N, N ', N "-tri (iso-propyl) borazine, B, B', B" -tri (iso-propyl) -N, N ', N "-trimethylborazine, B, B', B" -Tri (iso-propyl) -N, N ', N "-triethylborazine and the like.

  The alkyl borazine compound synthesized above is washed with water. The alkyl borazine compound is preferably water having a metal element content of 1 mass ppb or less and a halogen element content of 0.5 mass ppm or less, more preferably a metal element content of 0.1 mass ppb or less. And washing with water having a halogen element content of 0.05 mass ppm or less. When the product is washed with water, it is usually intended to remove water-soluble impurities. In the present invention, the washing water is used for the decomposition of impurities. However, removal of water-soluble impurities with washing water may be performed simultaneously. For example, metallic elements that are impurities can be dissolved in water as ions and removed from the alkylborazine compounds.

  When the alkylborazine compound is washed with water, the manner of washing is not particularly limited as long as the halogenated borazine compound contained in the alkylborazine compound can be decomposed by the washing water. For example, the alkylborazine compound is washed using a separatory funnel supplied with an organic solvent such as toluene in which a solid material made of the obtained borazine compound is dissolved and ion-exchanged water. The amount of cleaning water used may be determined according to the amount of alkylborazine compound to be cleaned and the mode of cleaning.

3. Method for purifying synthesized borazine compound (third embodiment)
The borazine and trialkylborazine compounds obtained in the first form and the hexaalkylborazine compounds obtained in the second form may be purified to further increase the purity of the borazine compounds. The method for purifying the borazine compound is not particularly limited, and for example, filtration purification, distillation purification, sublimation purification and the like can be used alone or in combination. Apparatuses and conditions such as filtration purification, distillation purification, and sublimation purification are not particularly limited, and those skilled in the art can appropriately implement them based on known knowledge.

  According to the above purification method, the purity of the synthesized borazine compound can be further increased, but the present invention is further characterized in that the borazine compound obtained by the above synthesis step is contacted with a metal removing agent. Have. As a result of removing metal atoms in the synthesis system by bringing the borazine compound into contact with a metal remover, the purity of the borazine compound is further increased, and the performance of a semiconductor interlayer insulating film manufactured using the borazine compound is improved. sell.

  The metal removing agent in the present invention is not limited to the following, but is preferably a metal ion scavenger, a metal ion sequestering agent (chelating agent), a metal ion adsorbent, an ion exchange resin, an inorganic ion exchanger, and a surface activity. It is 1 or more types selected from the group which consists of agent gel. The metal removing agent is more preferably a metal ion sequestering agent (chelating agent), a metal ion adsorbent or an ion exchange resin, and still more preferably a metal ion adsorbent or an ion exchange resin. Here, when the metal removing agent is used as a filter, a high-purity borazine compound can be obtained more easily. In the present application, the filter is hereinafter referred to as a metal (ion) removal filter. Therefore, the metal removal agent in the present invention is most preferably a metal (ion) removal filter using the metal ion adsorbent or the ion exchange resin as a filter. The route for obtaining the metal (ion) removal filter is not particularly limited, and may be a commercially available one. The filtration accuracy (pore diameter) of the metal (ion) removal filter is preferably 0.1 to 2 μm, and more preferably 0.1 to 0.8 μm. The filtration temperature of the metal (ion) removal filter is preferably room temperature (generally 1 to 40 ° C.) to 90 ° C., more preferably room temperature to 50 ° C. And although the pressurization conditions of the said metal (ion) removal filter change with kinds of filter, it is preferable that it is 0.2 MPa or less, and it is more preferable that it is 0.1 MPa or less. When the filtration accuracy (pore diameter), filtration temperature, and pressure conditions during filtration are within such ranges, each metal atom can be effectively removed. Note that other filtering conditions and the like can be appropriately set by those skilled in the art, and are omitted here. The source of the metal atom to be removed is mainly a metal atom derived from the raw material, but there may also be a metal atom present in the atmosphere. Therefore, the metal atom to be removed by the present invention is not particularly limited.

In the step of bringing the synthesized borazine compound into contact with the metal removing agent, the metal is removed from the borazine compound.
(1) It may be performed after the synthesis of the borazine compound, (2) When the synthesized borazine compound is purified by distillation (sublimation), it may be performed thereafter, and (3) the synthesized borazine compound is distilled (sublimated). In the case of purification, the distillation may be performed after dissolving the distilled (sublimation) purified borazine compound in a solvent.

  The content of each metal element with respect to the mass of the borazine compound produced by the production method of the present invention is preferably 20 mass ppb or less, more preferably 10 mass ppb or less. When the content is within such a range, the purity of the borazine compound can be increased, and the performance of a semiconductor interlayer insulating film manufactured using the borazine compound can be sufficiently improved. In addition, the measuring method of content of each said metal element is a method as described in the below-mentioned Example.

  The borazine compound produced by the production method of the present invention preferably has a purity of 99.0% by mass or more, more preferably 99.5% by mass or more, and particularly preferably 99.9% by mass or more. . Here, the value measured by gas chromatography is adopted as the purity value of the borazine compound. By using such a high-purity borazine compound, the performance of a product such as a semiconductor element can be improved. In addition, the measuring method of the purity of the said borazine compound is a method as described in the below-mentioned Example.

  Although the manufactured borazine compound is not particularly limited, the borazine compound can be used for forming an interlayer insulating film for a semiconductor, a barrier metal layer, an etch stopper layer, and the like. In that case, the borazine compound may be used as it is, or a compound obtained by modifying the borazine compound may be used. A polymer obtained by polymerizing a borazine compound or a borazine compound derivative may be used as a raw material for an interlayer insulating film for a semiconductor, a barrier metal layer, or an etch stopper layer. Hereinafter, “borazine compounds”, “derivatives of borazine compounds”, and “polymers resulting therefrom” are collectively referred to as “borazine ring-containing compounds”.

  As a method for forming an interlayer insulating film for semiconductor, a barrier metal layer, or an etch stopper layer using a borazine ring-containing compound, for example, a solution-like or slurry-like composition containing a borazine ring-containing compound is prepared. A technique of forming a coating film by applying to a desired site can be used.

  Hereinafter, embodiments of the present invention will be described in more detail using examples and comparative examples. However, the technical scope of the present invention is not limited to the following embodiments.

  In the following Examples and Comparative Examples, the content of each metal atom in the borazine compound was measured using ICP-MS (high frequency emission mass spectrometer) ELAN DRCII (manufactured by PerkinElmer Japan Co., Ltd.). The ICP-MS measurement was performed by diluting and decomposing the sample 20 times with methanol (“Methanol Electronics Industry” manufactured by Kanto Chemical Co., Ltd.), and further 2% by mass nitric acid aqueous solution (“Titanium nitrate TAMAPURE manufactured by Tama Chemical Industry Co., Ltd.). -AA-100 "was diluted with ultrapure water" Milli-Q ElementA-10 "manufactured by Nihon Millipore Co., Ltd.) to prepare a hydrolyzed solution for analysis by diluting the degradation product 10 times. Went.

  Furthermore, the purity of the borazine compound was measured using gas chromatography. The measurement conditions are as follows.

<Synthesis example>
To a three-necked round bottom flask (4 L volume) equipped with a dropping funnel and a condenser, monomethylamine hydrochloride (boiling point: 225 to 230 ° C.) (300 g) and triglyme (boiling point: 216 ° C.) 1000 g) and the reaction system was heated to 150 ° C.

  On the other hand, sodium borohydride (188 g) was prepared and added to separately prepared triglyme (1000 g) to prepare a slurry.

  The sodium borohydride slurry prepared above was gradually added to the reaction system heated to 150 ° C. over 90 minutes.

  After the addition of the slurry, the reaction system was heated to 170 ° C. over 20 minutes and aged for 2 hours to proceed with the synthesis reaction of N, N ′, N ″ -trimethylborazine (TMB) (boiling point 133 ° C.). After aging, the cooling pipe was removed, a Claisen connecting pipe and a Liebig cooling pipe were attached, the reaction solution was heated from 170 ° C. to 210 ° C. over 3 hours, and TMB was taken out by distillation. In the pressure, distillation was performed at a distillation temperature of 155 to 160 ° C., and a fraction having a distillation temperature of 130 to 133 ° C. was fractionated and purified.

<Example>
TMB obtained by the above synthesis method is transferred to a sealed container, and under a pressurized condition of 0.1 MPa or less under a clean nitrogen atmosphere, a commercially available filter for removing trace metals, Zeta Plus EC series-SH grade (Cuno Co., Ltd.) The product was filtered using When each metal content in TMB after filtration was measured by ICP-MS, the results shown in the following table were obtained. Moreover, the purity of TMB after filtration was 99.92% by mass.

<Comparative example>
When the content of each metal in TMB was measured by ICP-MS without filtering TMB obtained by the above synthesis method, the results shown in the following table were obtained. Moreover, the purity of TMB was 99.90% by mass.

  From the results shown in the above Examples and Comparative Examples, the content of each metal atom in the borazine compound obtained by the synthesis by removing the metal atom in contact with the metal remover (filtration) according to the present invention was determined. It has been shown that it is possible to control to very low values. Therefore, according to the present invention, it has been shown that the purity of the synthesized borazine compound can be further improved, and as a result, the performance of a semiconductor interlayer insulating film manufactured using the borazine compound can be further improved.

  When an interlayer insulating film manufactured using a borazine compound is used in an LSI, the presence of metal atoms in the material adversely affects the performance of the semiconductor element, and therefore extremely high quality is required. Therefore, it is necessary to control the content of metal atoms in the material to about several mass ppb. Moreover, since sodium etc. are contained also in air | atmosphere, in order to control to about several mass ppb, severe process control is required in the past, and huge cost is required. However, according to the present invention, as described above, a borazine compound in which each metal atom is reduced to about several mass ppb can be produced. Furthermore, the production method of the present invention, in which the metal removing agent is added to the synthesized borazine compound to remove the metal, is an unprecedented technique, and the content of each metal atom is reduced to several mass ppb very easily. From the above results, it is shown that this is a very excellent technique that can be adjusted.

Claims (1)

Chemical formula 1:

(In the above formula, R is independently selected from the group consisting of a hydrogen atom, an alkyl group and a cycloalkyl group)
A method for producing a borazine compound, comprising a step of synthesizing the borazine compound represented by formula (1) and a step of bringing the borazine compound into contact with a metal removing agent.