JP2007277152A - Cleaning method of apparatus for borazine compound and apparatus for borazine compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means for cleaning an apparatus for a borazine compound once used for the synthesis or preservation of a borazine compound to such a high degree that the contamination, by impurities or fine particles, of a borazine compound to be synthesized or preserved next time using the apparatus is suppressed to the minimum. <P>SOLUTION: The cleaning method of the apparatus for borazine compounds comprises a cleaning step (I) of cleaning the apparatus using an organic compound and a cleaning step (II) of cleaning the apparatus using water having an electroconductivity of 1 μS/cm or less at 25°C after the cleaning step (I). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an apparatus for borazine compounds. In particular, the present invention relates to a method for cleaning an apparatus for borazine compounds.

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

  Various compounds have been proposed as borazine compounds so far. For example, an alkyl borazine compound in which a boron site is substituted with an alkyl group has very excellent characteristics as a low dielectric constant material (see, for example, Patent Document 2).

  Conventionally, borazine compounds have only been synthesized in a small amount at a laboratory level using a flask or the like as a reaction vessel. On the other hand, in view of the usefulness of the borazine compound, it is clear that it is necessary to synthesize in a large amount in a larger scaled-up reaction vessel in view of mass production in the future.

  Here, considering the case of synthesizing a large amount of a borazine compound in a large-scale plant such as a factory, an apparatus that can come into contact with the borazine compound (for example, a pipe connecting a reaction apparatus and a purification apparatus, or a borazine compound from a purification apparatus) It is expected that borazine compounds and other impurities (for example, halogens and by-products derived from unreacted raw materials) will adhere to piping for taking out the components; hereinafter referred to simply as “borazine compound apparatus”). In addition, when a borazine compound is synthesized over a long period of time, piping is corroded, and the eluted metal or the like is expected to be mixed into the deposit as fine particles. If the synthesis of the borazine compound is continued with such deposits left unattended, impurities and fine particles may be mixed into the borazine compound as a product, leading to a decrease in quality such as a decrease in purity. In the semiconductor field such as an interlayer insulating film in an LSI, the presence of impurities and fine particles in the material adversely affects the characteristics of the semiconductor element and the like, and therefore extremely high quality is required. Therefore, when synthesizing a large amount of a borazine compound in a large-scale plant or the like, it is considered necessary to periodically stop the operation of the plant and open the apparatus for cleaning.

Conventionally, it has been disclosed that, as a means for cleaning a compound synthesizer, for example, it is effective to clean, with higher alcohols, dirt adhering to an apparatus that sulfonates or sulfates an organic compound with sulfur trioxide gas. (See Patent Document 3). In Patent Document 3, examples of the higher alcohol include higher alcohols having an alkyl average carbon chain length of 6 to 18 (specifically, lauryl alcohol, myristyl alcohol, etc.) and ethylene oxide adducts thereof.
JP 2000-340689 A JP 2003-119289 A JP 2000-129293 A

  However, as a result of intensive studies by the present inventors, in accordance with the technique described in Patent Document 3, the borazine compound apparatus is cleaned using higher alcohols, and the cleaned borazine compound apparatus is used. Even if the borazine compound is synthesized again, impurities and fine particles are still mixed in the obtained borazine compound, and it has been found that it is difficult to synthesize a satisfactory borazine compound from the viewpoint of purity. The present inventors have also found that the same problem can occur in a storage container for storing a borazine compound.

  In view of this, the present invention provides a borazine compound apparatus once used for the synthesis and storage of a borazine compound, and mixing of impurities and fine particles into the borazine compound synthesized or stored next time using the apparatus is minimized. The object is to provide a means that can be cleaned to a high degree.

  The present inventors have conducted intensive research to solve the above problems. As a result, it has been found that the above problem can be solved by adopting a two-step cleaning method of cleaning the apparatus using an organic compound and then cleaning the apparatus using water with extremely high purity. The present invention has been completed.

  That is, the present invention is a method for cleaning an apparatus for a borazine compound, and includes a cleaning step (I) for cleaning the apparatus using an organic compound, and an electrical conductivity at 25 ° C. of 1 μS after the cleaning step (I). And a cleaning step (II) for cleaning the device with water of not more than / cm.

  According to the present invention, the apparatus for borazine compounds once used for the synthesis and storage of borazine compounds can be highly cleaned. As a result, the contamination of borazine compounds synthesized or stored next time using this equipment is minimized, and the purity of the synthesized borazine compounds is maintained at a high value over a long period of time. Yes.

  Embodiments of the present invention will be described below.

  The present invention relates to a method for cleaning a device for borazine compounds, wherein the device is cleaned using an organic compound (I), and the electrical conductivity at 25 ° C. is 1 μS / cm after the cleaning step (I). And a cleaning step (II) for cleaning the device using the following water.

  First, “borazine compound” and “device for borazine compound” will be described.

  The “borazine compound” means a compound having a borazine ring skeleton, and is represented by the following chemical formula 1, for example.

In the formula, each R ₁ and each R ₂ may be the same or different, and are a hydrogen atom or 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 1-8, More preferably, it is 1-4, More preferably, it is one. Specific examples of the alkyl group include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group, hexyl group, heptyl group. Octyl group, nonyl group, decyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group, and the like. Alkyl groups other than these may be used. Examples of the borazine compound when R ₂ is a hydrogen atom 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) bo Gin, N, N ′, N ″ -tri (n-hexyl) borazine, N, N ′, N ″ -tricyclohexylborazine, N, N′-dimethyl-N ″ -ethylborazine, N, N′-diethyl- N "-methylborazine, N, N'-dimethyl-N" -propylborazine and the like can be mentioned. Examples of the borazine compound in the case where R ₂ is an alkyl group include B, B ′, B ″ -trimethylborazine, B, B ′, B ″ -triethylborazine, B, B ′, B ″ -tri ( n-propyl) borazine, B, B ′, B ″ -tri (isopropyl) borazine, B, B ′, B ″ -tri (n-butyl) borazine, B, B ′, B ″ -tri (isobutyl) borazine, B, B ′, B ″ -tri (tert-butyl) borazine, B, B ′, B ″ -tri (1-methylbutyl) borazine, B, B ′, B ″ -tri (2-methylbutyl) borazine, B, B ′, B ″ -tri (neopentyl) borazine, B, B ′, B ″ -tri (1,2-dimethylpropyl) borazine, B, B ′, B ″ -tri (1-ethylpropyl) borazine, B, B ′, B ″ -tri (n-hexyl) borazine, B, B ′, B ″ -to Examples thereof include cyclohexylborazine, B, B′-dimethyl-B ″ -ethylborazine, B, B′-diethyl-B ″ -methylborazine, B, B′-dimethyl-B ″ -propylborazine, and the like. In view of stability such as water resistance and handleability, the borazine compound is preferably N-alkylborazine in which an alkyl group is bonded to the nitrogen atom of the borazine ring skeleton.

Further, the borazine compound has B, B ′, B ″ -trimethyl in which both the nitrogen atom and boron atom of the borazine ring skeleton are substituted with an alkyl group (that is, both R ₁ and R ₂ are alkyl groups). -N, N ', N "-trimethylborazine, B, B', B" -trimethyl-N, N ', N "-triethylborazine, B, B', B" -triethyl-N, N ', N " -Alkyl borazine compounds, such as trimethylborazine, may be sufficient.

The technical scope of the present invention is not limited by the method for synthesizing the borazine compound, and conventionally known knowledge can be appropriately referred to. Here, an example and a method of synthesizing a borazine compound represented by the above formula 1, ABH 4 _(A is lithium atom, sodium atom or potassium atom) and an alkali boron hydride represented by the ( RNH ₃ ) _n X (R is a hydrogen atom or an alkyl group, X is a sulfuric acid group or a halogen atom, and n is 1 or 2). Illustrated.

In alkali borohydride (ABH ₄ ), A is a lithium atom, a sodium atom or a potassium atom. Examples of alkali borohydrides include sodium borohydride and lithium borohydride.

In the amine salt ((RNH ₃ ) _n X), R is a hydrogen atom or an alkyl group, and X is a sulfate group or a halogen atom. And when X is a sulfate group, n is 2, and when X is a halogen atom, n is 1. As described above, when n is 2, R may be the same or different. In consideration of the yield of the synthesis reaction and the ease of handling, R is preferably the same 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 1-8, More preferably, it is 1-4, More preferably, it is one. Specific examples of the alkyl group include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group, hexyl group, heptyl group. Octyl group, nonyl group, decyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group, and the like. Alkyl groups other than these may be used. Examples of amine salts include 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 ) Can be mentioned.

  What is necessary is just to select the alkali borohydride and amine salt to be used according to the structure of the borazine compound to synthesize | combine. For example, when producing N-methylborazine in which a methyl group is bonded to the nitrogen atom constituting the borazine ring, an amine salt such as monomethylamine hydrochloride, where R is a methyl group, is used as the amine salt. Good.

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

  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 alkali borohydride and the amine salt are not particularly limited. Reaction temperature becomes like this. Preferably it is 20-250 degreeC, More preferably, it is 50-240 degreeC, More preferably, it is 100-220 degreeC. 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.

  On the other hand, an alkyl borazine compound is prepared by using a halogenated borazine compound such as B, B ′, B ″ -trichloro-N, N ′, N ″ -trialkylborazine as a starting material, and using the Grignard reagent as the chlorine of the compound. It can be synthesized by substituting an atom with an alkyl group (see DT HOWORTH and LF HOHNSTEDT, J. Am. Chem. Soc., 82, 3860 (1960)).

  The size and type of the synthesis apparatus may be determined according to the environment and scale. For example, if a large amount of borazine compound is synthesized, an industrial scale synthesizer can be used.

  The synthesized borazine compound can be purified as necessary. As a purification method of the borazine compound, for example, distillation purification is used.

  The size and type of the distillation purification apparatus may be determined according to the environment and scale. For example, if a large amount of borazine compound is to be processed, an industrial scale distillation column can be used.

  The temperature at the time of distillation purification is not particularly limited, and can be appropriately set according to the type of borazine compound synthesized. For example, the temperature is usually about 100 to 150 ° C.

  Furthermore, for the purpose of improving the purity of the obtained borazine compound, an additional treatment such as a filtration treatment may be performed.

  “Apparatus for borazine compounds” means all apparatuses that can come into contact with borazine compounds in all industrial stages such as synthesis and storage of borazine compounds. For example, in the method for synthesizing a borazine compound exemplified in the above description, the borazine compound can come into contact with a synthesizer or a distillation purification apparatus. Moreover, when a filtration process is performed, a borazine compound can also contact a filtration apparatus. Further, the borazine compound can also come into contact with the piping connecting the devices so that the borazine compound can flow between these devices. Therefore, these synthesis devices, distillation purification devices, filtration devices, pipes, etc. are all included in the concept of “device for borazine compounds”.

  However, the form of the apparatus for borazine compounds is not limited to these. Usually, industrially synthesized borazine compounds are filled in borazine compound storage containers and stored in a sealed state. If necessary, the borazine compound is transported in a state of being filled in the container, taken out from the container at the transport destination, and used for the purpose of forming an interlayer insulating film for a semiconductor. Here, similarly in the used borazine compound storage container, problems may occur in the synthesis apparatus and its piping. That is, since it is almost impossible to completely remove the borazine compound filled in the container from the container at the time of use, a certain proportion of the borazine compound has to remain in the container. The borazine compound remaining in the container is hydrolyzed by the NB bond by contact with moisture in the air, and decomposed products (for example, methylamine and boric acid) are generated as impurities. Therefore, even if the purity of the originally filled borazine compound is extremely high, it is inevitable that impurities are mixed during the collection of the used borazine compound storage container. And even if it uses the conventionally well-known method to wash | clean the used borazine compound storage container which the impurity mixed at the time of collection | recovery in this way, it is difficult to achieve sufficient washing | cleaning. As a result, these impurities are mixed in the borazine compound to be filled next time, which may cause problems such as a decrease in the purity of the borazine compound.

  On the other hand, when such a used borazine compound storage container is washed by the method of the present invention, contamination of impurities into the borazine compound to be filled next time is minimized, and the purity of the borazine compound to be filled is reduced. Occurrence of problems such as degradation can be prevented. Therefore, the “borazine compound storage container” can also be included in the concept of “the apparatus for borazine compound” in the present invention.

  Next, the cleaning process which is a characteristic configuration of the present invention will be described in detail in the order of the cleaning process (I) and the cleaning process (II).

[Washing step (I)]
In this step, the borazine compound apparatus is cleaned using an organic compound. Thereby, the borazine compound and other organic impurities adhering to the apparatus are dissolved in the organic compound and washed away.

  In this step, the organic compound used for cleaning is not particularly limited as long as it does not adversely affect the borazine compound in contact with the apparatus or the apparatus even when used for cleaning the apparatus for borazine compound. Is not particularly limited. The organic compound used for washing may be hydrophobic or hydrophilic. Examples of the hydrophobic organic compound include aliphatic hydrocarbon compounds such as n-pentane, cyclopentane, n-hexane, cyclohexane, n-heptane and methylcyclohexane; aromatic hydrocarbon compounds such as benzene, toluene and xylene; acetic acid And aliphatic esters such as ethyl. Examples of the hydrophilic organic solvent include lower aliphatic alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, and isopropyl alcohol; aliphatic ketones such as acetone; dioxane, tetrahydrofuran, methoxy (poly) ethylene glycol, and the like. Ether compounds; amide compounds such as ε-caprolactam and N, N-dimethylformamide; sulfoxide compounds such as dimethyl sulfoxide; ethylene glycol, diethylene glycol, propylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, 1,3-propanediol , Dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, polypropylene glycol, glycerin, polyglycerin 2-butene 1,4-diol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,2- Examples thereof include polyhydric alcohol compounds such as cyclohexanol, trimethylolpropane, diethanolamine, and triethanolamine.

  Only one kind of these organic compounds may be used for washing alone, or two or more kinds may be mixed and used for washing.

  There is no particular limitation on the specific form of washing, and conventionally known knowledge relating to washing of apparatuses used for compound synthesis and storage can be appropriately referred to. For example, when the synthesizer is washed after the synthesis of the borazine compound, for example, raw materials and reaction products remaining in the synthesizer are discharged out of the system and the apparatus is opened. Next, the synthesis apparatus may be washed using the organic compound as described above. Although the specific operation of washing is not particularly limited, for example, washing with a hose or a spray is exemplified. In addition, wiping is also effective for cleaning parts that are difficult to wash. Such a cleaning operation may be performed manually, or may be performed using a semi-automated or automated apparatus. On the other hand, in consideration of washing of the borazine compound storage container, the above-described over-washing and wiping are also effective, but a technique of filling the container with the above-described organic compound and allowing to stand may be used. . Moreover, the washing | cleaning in this process can be accelerated | stimulated by applying a vibration to the apparatus wash | cleaned as needed. Examples of the vibration device used at this time include an ultrasonic wave application device, but are not limited thereto.

  The number of washings using the organic compound in this step is not particularly limited, and may be one or more times, but it is possible to achieve sufficient removal of organic substances (residual borazine compounds, by-products, etc.). From the above, the number of washings with an organic compound is preferably 2 to 50 times, more preferably 3 to 10 times. If the number of cleanings is too large, there is a possibility that the cleaning effect corresponding to the increase in the number of cleanings cannot be obtained.

  In this step, the temperature at which the organic compound is subjected to washing is not particularly limited, but is preferably 0 to 70 ° C, more preferably 0 to 50 ° C, and further preferably 10 to 30 ° C. By performing cleaning using an organic compound having a temperature within such a range, excellent cleaning efficiency can be achieved.

In this step, the amount of the organic compound used for washing is not particularly limited, but the amount used per washing area is preferably 0.1 to 10.0 mL / cm ² , more preferably 0.2 to 5 0.0 mL / cm ² , more preferably 0.2 to 2.0 mL / cm ² . By setting the amount of the organic compound used within such a range, sufficient cleaning can be achieved without causing an increase in cleaning cost.

  In a preferred form of this step, first, the borazine compound apparatus is washed with a hydrophobic organic compound, and then the apparatus is washed with a hydrophilic organic compound. According to such a form, the hydrophobic residual borazine compound and the hydrophobic impurities (for example, by-products) are also washed by the washing with the hydrophobic organic compound, followed by the washing with the hydrophilic organic compound. Thus, hydrophilic impurities (for example, by-products) are washed. Then, the cleaning operation can smoothly shift to cleaning using water in the cleaning step (II) described later. That is, by washing with water in the washing step (II) after washing with the hydrophilic organic compound, removal of the hydrophilic organic compound used for washing can be sufficiently achieved.

  In this form, the number of times of washing with each of the hydrophobic organic compound and the hydrophilic organic compound and the ratio of the amount of each compound used are not particularly limited, and can be appropriately determined according to the type and amount of impurities that need to be washed. . If a preferable example is given, the frequency | count of washing | cleaning by a hydrophobic organic compound becomes like this. Preferably it is 2-50 times, More preferably, it is 3-10 times. Moreover, the frequency | count of washing | cleaning by a hydrophilic organic compound becomes like this. Preferably it is 2-50 times, More preferably, it is 3-10 times. If the number of cleanings is too large, there is a possibility that the cleaning effect corresponding to the increase in the number of cleanings cannot be obtained. Moreover, when a preferable example of the ratio of the amount used is given, the volume ratio of hydrophobic organic compound: hydrophilic organic compound is preferably 1: 0.5 to 1: 4, more preferably 1: 1 to 1: 2. However, it is needless to say that a form outside these ranges may be adopted. In addition, the said volume ratio shall be computed based on the total value of the usage-amount of multiple times, when the washing | cleaning by at least one of a hydrophobic organic compound and a hydrophilic organic compound is performed in multiple times.

  In addition, after the completion of the cleaning process (I), when the process proceeds to the cleaning process (II), an additional cleaning process may be performed for the purpose of washing away the organic compound used in the cleaning process (I). For such cleaning treatment, for example, general pure water can be used.

[Washing step (II)]
In this step, after the above-described washing step (I), the borazine compound apparatus is washed using predetermined water having high purity. Thereby, impurities (for example, halogen, metal element, other fine particles, etc.) adhering mainly to the apparatus are washed away.

  The water used for washing in this step has an electrical conductivity at 25 ° C. of 1 μS / cm or less, preferably 0.5 μS / cm or less, more preferably 0.1 μS / cm or less, and even more preferably 0.06 μS / cm or less. Indicates the value of. Such form of water has a very low impurity content. Therefore, by performing the washing step (II) using such water, impurities and fine particles that have not been washed in the washing step (I) are removed and further used for washing purposes in the washing step (I). Organic compounds are also washed away. As a result, contamination of impurities into the borazine compound when the borazine compound comes into contact with the cleaned apparatus next time can be minimized. Here, from the viewpoint of using high-purity water for washing, the lower limit value of the electrical conductivity of the water used is not particularly limited, and the lower the better, the better, but considering the difficulty of availability, the electrical conductivity In many cases, 0.056 μS / cm or more is sufficient. In the present specification, as the value of “electric conductivity of water at 25 ° C.”, a value measured by the method described in Examples described later is adopted.

  There are no particular restrictions on the route for obtaining water exhibiting the predetermined electrical conductivity described above. When such water is commercially available, it may be used by purchasing the product, or the purity of low-purity water may be improved using a commercially available device.

  It is essential that the water used for washing in this step exhibits an electric conductivity within the above-mentioned range, but in a more preferred form, the content of contained particles is also defined. That is, in this embodiment, the content of particles having a particle size of 0.5 μm or more in the water used in this step is 100 / mL or less, more preferably 50 / mL or less, and even more preferably 10 Pieces / mL or less. By performing the washing step (II) using such form of water, the washing efficiency in the washing step (II) can be further improved. Here, from the viewpoint of using high-purity water for washing, the lower limit of the content of the particles in the water used is not particularly limited, and the lower the better. In the present specification, as the value of “the content of particles having a particle diameter of 0.5 μm or more in water”, a value measured by the method described in Examples described later is adopted. There is no particular limitation on the route of obtaining water with a low content of such particles. When such water is commercially available, it may be used by purchasing the product, or by using commercially available equipment to obtain water with a low particle content by means such as filtration. Also good.

  There is no particular limitation on the specific form of washing in this step, and conventionally known knowledge relating to washing of apparatuses used for compound synthesis and storage is appropriately referred to. For example, the form described above for washing step (I) is the same. It can be adopted.

  There is no particular limitation on the number of times of washing with water in this step, and it may be one or more times. From the viewpoint of achieving sufficient removal of impurities and fine particles, washing with water is possible. The number of times is preferably 2 to 50 times, more preferably 3 to 10 times. If the number of cleanings is too large, there is a possibility that the cleaning effect corresponding to the increase in the number of cleanings cannot be obtained.

  In this step, the temperature at which water is subjected to washing is not particularly limited, but is preferably 0 to 70 ° C, more preferably 20 to 60 ° C, and further preferably 20 to 50 ° C. By performing cleaning using water having a temperature within such a range, excellent cleaning efficiency can be achieved.

In this step, the amount of water used for washing is not particularly limited, but the amount used per washing area is preferably 0.2 to 10.0 mL / cm ² , more preferably 0.2 to 5. 0 mL / cm ² , more preferably 0.2 to 2.0 mL / cm ² . By setting the amount of water used within such a range, sufficient cleaning can be achieved without causing an increase in cleaning cost.

If possible, this step is preferably performed in a clean room having a predetermined cleanliness (cleanliness class). This embodiment is particularly suitable when the borazine compound apparatus is a borazine compound storage container. Specifically, this step is preferably performed in a clean room that is cleaner than class 10000. In this specification, “cleanness (cleanliness class)” is a value according to FED-STD-209D (US Federal Standard, 1988). In this standard, “cleanness (cleanliness class)” is defined as the number of particles having a particle size of 0.5 μm or more per 1 ft ³ . Therefore, for example, “clean room cleaner than class 10000” means a clean room in which the number of particles having a particle diameter of 0.5 μm or more in the atmosphere is 10,000 / ft ³ or less. In addition, it is more preferable that this process is performed in a clean room cleaner than class 1000, and it is more preferable that it is performed in a clean room cleaner than class 100.

  As described above, in the cleaning step (II), the borazine compound apparatus is cleaned using water. If the water used at this time remains in the apparatus, it is synthesized or stored next time using the apparatus. The borazine compound may be decomposed by contact with the borazine compound. From such a viewpoint, in the present invention, it is preferable to further include a drying step of drying the borazine compound apparatus cleaned in the cleaning step (II).

  The drying means used in the drying step is not particularly limited, and a form conventionally used for drying after washing of an apparatus used for compound synthesis and storage can be similarly employed. For example, drying using a dryer or drying by injecting a chemical clean level inert gas (for example, nitrogen) can be exemplified.

  As described above, according to the cleaning method of the present invention, the borazine compound once used for the synthesis and storage of the borazine compound by cleaning the borazine compound apparatus by the cleaning step (I) and the cleaning step (II). The equipment can be highly cleaned. As a result, the contamination of borazine compounds synthesized or stored next time using this equipment is minimized, and the purity of the synthesized borazine compounds is maintained at a high value over a long period of time. Yes.

  Therefore, according to the present invention, an apparatus for borazine compounds cleaned by the above-described cleaning method of the present invention is provided. In a more preferred embodiment, the apparatus for borazine compounds is for storing borazine compounds for storing borazine compounds. It is a container.

  Here, the form of the borazine compound storage container such as the size and material is not particularly limited, and conventionally known knowledge can be referred to as appropriate. In order to store a small amount of borazine compound synthesized at the laboratory level, a small storage container may be used. Moreover, what is necessary is just to use a big storage container in order to preserve | save the large amount of borazine compounds synthesize | combined on the industrial level.

  As a material for the storage container, for example, a metal material such as stainless steel or Hastelloy, a plastic material such as polytetrafluoroethylene (PTFE), or the like may be employed. Among these, from the viewpoint of high pressure resistance, the container is preferably made of stainless steel. In order to further improve the corrosion resistance of the storage container, the inner surface of the container made of a material such as the metal may be coated with a resin. At this time, the resin used for the coating is not particularly limited, and examples thereof include polytetrafluoroethylene (PTFE) and polypropylene. Especially, it is preferable to coat using PTFE from a viewpoint that the improvement effect of corrosion resistance is excellent. Here, although there is no restriction | limiting in particular about the coating thickness of a resin coating, Preferably it is 10-3000 micrometers, More preferably, it is 500-1000 micrometers.

  Furthermore, the storage container is preferably sealable, and examples of means for enabling sealing of the container include a form in which a valve is provided in a part of the container.

  The apparatus for borazine compounds cleaned by the cleaning method of the present invention is extremely highly cleaned by using an organic compound and high-purity water. The degree of cleaning can be defined by the following parameters, for example. That is, the borazine compound apparatus (for example, a borazine compound storage container) provided by the present invention (preferably cleaned by the cleaning method of the present invention) has an electrical conductivity of 1 μS / cm or less at 25 ° C. When left standing for 1 hour after filling with water, the increase in the content of halogen ions (for example, chloride ion, bromide ion, etc.) in the water after standing for 1 hour is preferably 100 mass ppb or less, more preferably It is 50 mass ppb or less, More preferably, it is 10 mass ppb or less. Here, as the value of the content of halogen ions, a value measured by the method described in Examples described later is adopted. Also, the amount of increase in the content of metal elements (for example, sodium, calcium, aluminum, nickel, chromium, zinc, potassium, etc.) in water after standing for 1 hour is preferably 50 mass ppb or less, more preferably 20 mass ppb. Or less, more preferably 10 mass ppb or less. Here, as the value of the content of the metal element, a value measured by the method described in Examples described later is adopted. Furthermore, the amount of increase in the content of particles having a particle size of 0.5 μm or more in water after standing for 1 hour is preferably 100 / mL or less, more preferably 50 / mL or less, and even more preferably It is 10 pieces / mL or less. Here, as the value of the content of the particles, a value measured by the method described in Examples described later is adopted.

  In the present specification, values measured by the method described in Examples described later are adopted as the values of “content of halogen ion in water” and “content of metal element in water”. In addition, when a plurality of halogen ions or metal elements are contained in water or a borazine compound (see the form described later), the content is the total value of the contents of a plurality of halogen ions or the total value of the contents of a plurality of metal elements. Shall be adopted. In the measurement of these parameters, the amount of water filled in the borazine compound storage container is 10% or more, preferably 30% or more, more preferably 50% or more with respect to the container volume. . Of the borazine compound devices, for a sealable device such as a borazine compound storage container, after filling the device with water, the device may be sealed and the various parameters described above may be measured. For devices that are difficult to seal, such as pipes, prepare two sealable containers with the same cleanliness, fill them both with the same amount of water, and measure the above parameters on one of the two devices. What is necessary is just to set it as the parameter value in the said pipe | tube, making the said parameter in the water with which the other container was filled up as a control (comparison control) by immersing a desired apparatus.

  Furthermore, when the apparatus for borazine compounds provided by the present invention (preferably washed by the washing method of the present invention) is a borazine compound storage container, the container is sufficiently dried after washing, When the borazine compound is stored, the purity reduction can be controlled to a very small value. This degree can be defined by the following parameters, for example. That is, after the borazine compound is stored at 25 ° C. in the borazine compound storage container provided by the present invention and 30 days have passed, the purity decrease of the borazine compound is preferably 0.5% by mass or less. More preferably, it is 0.3 mass% or less, More preferably, it is 0.1 mass% or less. Note that “the decrease in the purity of the borazine compound is 0.5% by mass” means, for example, that the purity of the borazine compound at the start of storage is 99.8% by mass, after storage at 25 ° C. for 60 days. It means that the purity of the borazine compound is 99.3% by mass. That is, “decrease in purity” means a decrease in absolute purity of the borazine compound, not a relative value before and after storage. In addition, as a value of the purity of a borazine compound, the value measured by the method as described in the Example mentioned later shall be employ | adopted.

  The borazine compound storage container provided by the present invention can also be defined by other parameters. That is, the content of halogen ions (for example, chloride ions, bromide ions, etc.) in the borazine compound is stored in the borazine compound storage container provided by the present invention at 25 ° C. and after 30 days. The amount of increase is preferably 100 mass ppb or less, more preferably 50 mass ppb or less, and still more preferably 20 mass ppb or less. The absolute value of the halogen ion content in the borazine compound after storage is not particularly limited, but is preferably 10 ppm or less, more preferably 1 ppm or less, and even more preferably 200 ppb or less. Here, as a value of the content of halogen ions in the borazine compound, a value measured by a method described in Examples described later is adopted. Further, the increase in the content of metal elements (for example, sodium, calcium, aluminum, nickel, chromium, zinc, potassium, etc.) in the borazine compound is preferably 50 mass ppb or less, more preferably 20 mass ppb or less. More preferably, it is 10 mass ppb or less. The absolute value of the metal element content in the borazine compound after storage is not particularly limited, but is preferably 10 ppm or less, more preferably 1 ppm or less, and even more preferably 200 ppb or less. Here, as a value of the content of the metal element in the borazine compound, a value measured by a method described in Examples described later is adopted. Furthermore, the amount of increase in the content of particles having a particle size of 0.5 μm or more in the borazine compound is preferably 100 / mL or less, more preferably 50 / mL or less, and even more preferably 10 / mL. Less than mL. Here, as the value of the content of the particles, a value measured by the method described in Examples described later is adopted.

  Hereinafter, embodiments of the present invention will be described in more detail with reference to examples. However, the technical scope of the present invention is not limited only to the following embodiments.

<Example>
First, a SUS316L borazine compound storage container (2L) was prepared as a borazine compound apparatus.

[Washing step (I)]
Subsequently, using n-hexane (hydrophobic organic compound), the prepared container was washed by washing (100 mL × 3 times).

  Subsequently, using isopropyl alcohol (hydrophilic organic compound), the prepared container was washed by washing (100 mL × 3 times). Thereafter, the container was washed by washing with pure water (100 mL × 10 times).

[Washing step (II)]
Using an ultrapure water production apparatus (Nippon Millipore Corporation: Milli-Q Element A-10), water for use in washing in this step (hereinafter also referred to as “ultra pure water”) was prepared. The prepared ultrapure water showed an electric conductivity of 0.055 μS / cm at 25 ° C. according to an electric conductivity meter incorporated in the ultrapure water production apparatus. The content of particles having a particle size of 0.5 μm or more was measured and found to be 2 / mL. The value of “electrical conductivity” was measured by the following method. For the measurement of the content of particles having a particle diameter of 0.5 μm or more, a particle counter (manufactured by Particle Measuring Systems Inc. (PMS); AZ-SO2 / LS-200) using laser light scattering is used. Using.

  The container for storing the borazine compound washed in the washing step (I) was washed in a class 1000 clean room by using the ultrapure water obtained above (300 mL × 3 times).

<Evaluation>
In the above-described Examples, the cleaned borazine compound storage container was filled with ultrapure water and allowed to stand for 1 hour. Measure the halogen ion content, metal element content, and particle content of 0.5 μm or more in ultrapure water after standing for 1 hour, respectively, and correspond to the ultrapure water used for cleaning before filling. From the value, the increase amount of each value after being allowed to stand for 1 hour was calculated. As a result, the increase amount of the halogen ion content is 5 mass ppb, the increase amount of the metal element content is 3 mass ppb, and the increase amount of the particles having a particle diameter of 0.5 μm or more is 2 / pp. mL.

  In addition, ICS-1500 (made by Nippon Dionex Co., Ltd.) which is ion chromatography was used for the measurement of the content of halogen ions in ultrapure water. Moreover, ELAN DRCII (made by Perkin Elmer Japan Co., Ltd.) which is ICP-MS (high frequency emission mass spectrometer) was used for the measurement of the content of the metal element. Furthermore, a particle counter (manufactured by Particle Measuring Systems Inc. (PMS); LIQUIL AZ-SO2 / LS-200) using laser light scattering is used to measure the content of particles having a particle size of 0.5 μm or more. Using.

  Subsequently, the ultrapure water filled in the container was taken out and dried at 60 ° C. for 24 hours in a class 100 clean oven.

  In a class 10 clean glove box, N, N ′, N ″ -trimethylborazine having a purity of 99.9% by mass, which is a borazine compound, is filled into a container after drying, and the halogen ions in the borazine after 30 days have passed. The content, the content of the metal element, and the content of particles having a particle size of 0.5 μm or more, and the purity of the borazine compound are measured, respectively, and from the corresponding value in the borazine compound before filling, each after 30 days As a result, the increase in the halogen ion content was 17 mass ppb, the increase in the metal element content was 7 mass ppb, and particles having a particle size of 0.5 μm or more. The increase in the content was 5 / mL, and the purity reduction of N, N ′, N ″ -trimethylborazine was 0.01% by mass.

  The halogen ion content and metal element content in the borazine compound were measured by the following method. First, regarding the content of halogen ions, the borazine compound is diluted and decomposed 20 times with methyl alcohol (manufactured by Kanto Chemical Co., Inc .; methyl alcohol for electronics industry), and further the diluted product is diluted 20 times with ultrapure water. An analytical hydrolyzate is prepared. After passing this liquid through a cation adsorption column, it was measured using ISC-1500 (manufactured by Nippon Dionex Co., Ltd.) which is ion chromatography.

  In addition, the metal element content was diluted 20 times with methyl alcohol in the same manner as described above, and further diluted with a 2% by mass nitric acid aqueous solution (manufactured by Tama Chemical Industries Co., Ltd .; TAMAPURE-AA-100 nitric acid was diluted with ultrapure water. The hydrolyzate for analysis is prepared by diluting the degradation product 10 times in the above. This liquid was measured using ELAN DRCII (manufactured by Perkin Elmer Japan Co., Ltd.) which is an ICP-MS (high frequency emission mass spectrometer).

  Furthermore, the same method as described above was used to measure the content of particles having a particle size of 0.5 μm or more.

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

Equipment: GC-14B manufactured by Shimadzu Corporation
Column: Hitachi Science Systems, Ltd. Ultra Alloy (8H)
Carrier gas: Nitrogen Carrier gas flow rate: 3.0 mL / min Sample injection temperature: 300 ° C.
Detector temperature: 300 ° C
Sample injection volume: 0.2 μL
Column temperature: 50 ° C. (5 minutes) → Heated to 250 ° C. at a rate of temperature increase of 20 ° C./min
→ Temperature increased to 300 ° C. at a rate of 10 ° C./min→300° C. (10 minutes)
<Comparative example>
Except that the washing step (I) was not performed, the borazine compound storage container was washed and subjected to various evaluations in the same manner as in the above Examples.

  As a result, after the container was filled with ultrapure water and allowed to stand for 1 hour, the increase in the halogen ion content in the water was 830 mass ppb, the increase in the metal element content was 110 mass ppb, The increase in the content of particles having a particle size of 5 μm or more was 4600 particles / mL.

  Moreover, the increase amount of the halogen ion content in the borazine compound 30 days after filling with the borazine compound is 980 mass ppb, and the increase amount of the metal element content is 120 mass ppb, which is 0.5 μm or more. The increase in the content of particles having a particle size was 13000 / mL, and the purity reduction of N, N ′, N ″ -trimethylborazine was 2.1% by mass.

  From the results shown in the above Examples and Comparative Examples, according to the method for cleaning an apparatus for borazine compound of the present invention, the apparatus is cleaned to a very high degree, and impurities and fine particles are mixed into the borazine compound stored next time. It can be shown that it can be minimized.

Claims (10)

A method for cleaning an apparatus for borazine compounds,
A cleaning step (I) for cleaning the apparatus using an organic compound;
After the washing step (I), a washing step (II) for washing the device with water having an electrical conductivity at 25 ° C. of 1 μS / cm or less,
A method for cleaning an apparatus for a borazine compound. The washing step (I)
A cleaning step (Ii) for cleaning the device with a hydrophobic organic compound;
A cleaning step (I-ii) for cleaning the device using a hydrophilic organic compound after the cleaning step (I-i);
The cleaning method according to claim 1, comprising:   The cleaning method according to claim 1 or 2, further comprising a drying step of drying the device cleaned in the cleaning step (II).   The apparatus for borazine compounds wash | cleaned by the method of any one of Claims 1-3.   The apparatus for borazine compounds according to claim 4, which is a container for storing borazine compounds.   In the water after filling with water having an electric conductivity of 1 μS / cm or less at 25 ° C. and left for 1 hour, the increase in halogen ion content is 100 mass ppb or less, and the increase in metal element content Is an apparatus for a borazine compound in which the increase in the content of particles having a particle diameter of 0.5 μm or more is 100 / mL or less. The apparatus for borazine compounds according to claim 6,
The apparatus for borazine compounds which preserve | saves a borazine compound at 25 degreeC and the purity fall of the said borazine compound after progress for 30 days is 0.5 mass% or less. A device for a borazine compound according to claim 6 or 7,
The apparatus for borazine compounds which preserve | saves a borazine compound at 25 degreeC and the increase amount of the content of the halogen ion in the said borazine compound after progress for 30 days is 100 mass ppb or less. The apparatus for borazine compounds according to any one of claims 6 to 8,
The apparatus for borazine compounds which preserve | saves a borazine compound at 25 degreeC and the increase amount of the content of the metal element in the said borazine compound after progress for 30 days is 50 mass ppb or less. A borazine compound device according to any one of claims 6 to 9,
The apparatus for borazine compounds which preserve | saves a borazine compound at 25 degreeC, and the increase of the content of the particle | grains which have a particle size of 0.5 micrometer or more in the said borazine compound after 30-day progress is 100 pieces / mL or less.