KR101015212B1 - Preparing method of purified borazine compounds, filling method of purified borazine compounds, and container for preserving borazine compounds - Google Patents

Abstract

When preparing the purified borazine compound, the borazine compound is filtered under an atmosphere of 2000 vol ppm or less of water content. Alternatively, when the borazine compound is charged in the container, the borazine compound is charged in the container under an atmosphere of 2000 vol ppm or less. Or as a storage container for storing the borazine compound, a container for storing a borazine compound having a pressure resistance of 0.1 MPa or more.

Description

Preparation method of purified borazine compounds, filling method of purified borazine compounds, and container for preserving borazine compounds}

The present invention relates to borazine compounds. Borazine compounds are used, for example, for forming an interlayer insulating film for semiconductors, a barrier metal layer, and an etch stopper layer.

As the performance of information equipment increases, the design rules of LSI are getting finer every year. In the LSI manufacture of fine design rules, the materials constituting the LSI must be high performance and perform functions on the fine LSI.

For example, as for the material used for the interlayer insulating film in the LSI, the high dielectric constant causes the signal delay. In fine LSI, the influence of this signal delay is particularly large. For this reason, the development of a new low dielectric material which can be used as an interlayer insulating film has been demanded. In addition, in order to be used as an interlayer insulating film, not only the dielectric constant is low but also the characteristics such as moisture resistance, heat resistance, mechanical strength, etc. need to be excellent.

In response to this need, borazine compounds having borazine ring skeletons in their molecules have been proposed (see, eg, US Patent Application Publication No. 2002-58142). Since the borazine compound having a borazine ring skeleton has a low molecular polarization rate, the film formed has a low dielectric constant. Furthermore, the film formed is also excellent in heat resistance.

As borazine compounds, various compounds have been proposed so far. For example, an alkyl borazine compound in which the boron moiety is substituted with an alkyl group has very excellent properties as a low dielectric constant material (see, for example, US Patent Application Publication No. 2003-100175).

In the case where the borazine compound is used as, for example, the above-described interlayer insulating film for semiconductors, the smaller the impurity in the borazine compound used, the more preferable. For example, when using as an interlayer insulation film of a semiconductor, when there are too many impurities in the borazine compound used, there exists a possibility that the performance, such as an interlayer insulation film obtained, may fall. On the other hand, when there are few impurities in the borazine compound used, occurrence of the above problems can be suppressed.

The present inventors, for example, as a source of incorporation of impurities which may lead to the deterioration of the interlayer insulating film and the like as described above, for example, impurity in the air during the production of borazine compounds, filling or transport into containers, etc. I found it as a cause. In addition, the present inventors have found that the contact of the borazine compound with water may also cause the incorporation of impurities. That is, borazine compounds (e.g., N, N ', N "-trimethyl borazine), when contacted with water, NB bonds are hydrolyzed, resulting in decomposition products (e.g., methylamine and boric acid) as impurities. I found out that it is.

Conventionally, borazine compounds are usually synthesized only in small amounts at the laboratory level and stored in reagent bottles and the like. On the other hand, with future mass production in mind, it is likely that there will be a need for long-term preservation in larger containers.

In storing the borazine compound mass-produced here, consider the case where the drum can etc. which are used for preservation of a general compound are employ | adopted as a storage container. Such a container normally breathes in an atmosphere of atmospheric pressure, and the gas and the outside air in the container travel to some extent inside and outside the container. Therefore, when attempting to use the container generally used for the preservation of a compound as it is for the preservation of the borazine compound, the water contained in the outside air accompanies the inflow of the outside air into the container and causes decomposition of the borazine compound. There is a possibility.

As described above, impurities may be incorporated into the compound in many processes such as the production of borazine compounds, filling, transport, and storage into containers. However, as a means for effectively eliminating the incorporation of such impurities, a satisfactory one has not yet been proposed and the reality is awaiting the development of such means.

An object of the present invention is to provide a means capable of effectively suppressing the incorporation of impurities into the compound when preparing the borazine compound and when filling the prepared borazine compound in a container.

Another object of the present invention is to provide a means for inhibiting the inflow of external air containing water into a storage container when the borazine compound is stored, and preventing decomposition of the borazine compound under storage.

Another object of the present invention is to provide a borazine compound having a low content of impurities.

The present inventors conducted earnest research in order to achieve the title. As a result, it has been found that incorporation of impurities into the borazine compound in the production or filling of the borazine compound can be suppressed by controlling the moisture content in the atmosphere when the borazine compound is produced or filled. Furthermore, the present inventors have found that the incorporation of impurities into the borazine compound in the storage of the borazine compound can be suppressed by controlling the internal pressure pressure of the storage container used for the storage of the borazine compound to a predetermined value or more.

That is, one embodiment of the present invention, a method for producing a purified borazine compound having a borazine compound preparation step for preparing a borazine compound and a filtration step of filtering the prepared borazine compound in an atmosphere having a water content of 2000 vol ppm or less. to be.

Another embodiment of the present invention is a borazine compound having a content of impurities of 100 µm or more in particle size of 0.5 µm or more.

Another form of the present invention is a method for filling a borazine compound having a filling step of filling the borazine compound in a container under an atmosphere having a moisture content of 2000 vol ppm or less.

Another embodiment of the present invention is a container for storing a borazine compound having a pressure resistance of 0.1 MPa or more.

Another embodiment of the present invention is a borazine compound having a purity decrease of 1% or less when stored at 25 ° C. for 60 days.

One embodiment of the present invention relates to a technique for suppressing the incorporation of impurities into the compound at the time of producing the borazine compound. Specifically, the form is a method for producing a purified borazine compound having a borazine compound preparation step of preparing a borazine compound and a filtration step of filtering the prepared borazine compound in an atmosphere having a water content of 2000 vol ppm or less.

In the production method of this embodiment, the borazine compound is filtered under an atmosphere having a predetermined moisture content. Thereby, the incorporation of impurities into the purified borazine compound can be effectively suppressed.

Next, the manufacturing method of this form is demonstrated in detail in process order.

[Prepared Compound Preparation Step]

In the manufacturing method of this form, a borazine compound is prepared first.

The specific form of the borazine compound to be prepared is not particularly limited and conventional knowledge can be appropriately referred to. Borazine compounds are represented by the following formula (1), for example.

[Formula 1]

In formula, each R <_1> and each R <_2> may be same or different, respectively, and is a hydrogen atom or an alkyl group. The alkyl group may be any of linear, branched or cyclic. Although carbon number which an alkyl group has is not specifically limited, Preferably it is 1-8 pieces, More preferably, it is 1-4 pieces, 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, An octyl group, a nonyl group, a decyl group, a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, etc. are mentioned. Alkyl groups other than these may be used. And as an example of the borazine compound when R <_2> is a hydrogen atom, borazine, N, N ', N "-trimethyl borazine, N, N', N" -triethyl borazine, 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-dimethyl propyl) borazine, N, N', N" -tri (1-ethyl propyl) borazine, 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, B, B', B" -trimethyl borazine, 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 "-tree (1, 2- Dimethyl propyl) borazine, B, B ', B "-tri (1-ethyl propyl) borazine, B, B', B"-tree (n-hexyl) borazine, B, B ', B "-tree Cyclohexyl borazine, B, B'-dimethyl-B "-ethylborazine, B, B'-diethyl-B" -methylborazine, B, B'-dimethyl-B "-propylborazine, etc. are mentioned. In addition, in consideration of stability and handleability such as water resistance and the like of the borazine compound produced, the borazine compound is preferably N-alkyl borazine.

In addition, the borazine compound prepared has B, B ', B "-trimethyl-N, N', N" -trimethyl in which the nitrogen moiety and the boron moiety are substituted with an alkyl group (i.e., both R ₁ and R ₂ are alkyl groups). Borazine, B, B ', B "-trimethyl-N, N', N" -triethylborazine, B, B ', B "-triethyl-N, N', N" -trimethyl borazine An alkyl borazine compound may be sufficient.

The acquisition route of the borazine compound prepared is not specifically limited. When the product of a borazine compound is marketed, the thing which purchased the said product may be used, and the borazine compound prepared by itself may be used.

The method of preparing the borazine compound by itself is not particularly limited. As an example of the preparation method of the borazine compound represented by the formula (1), boron hydride alkali represented by ABH ₄ (A is a lithium atom, a sodium atom or a potassium atom), (RNH ₃ ) _n X (R is hydrogen A method of reacting an amine salt represented by an atom or an alkyl group, X is a sulfuric acid group or a halogen atom, n is 1 or 2) in a solvent.

In boron hydride alkali (ABH ₄ ), A is a lithium atom, a sodium atom or a potassium atom. Examples of the boron hydride alkali 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 sulfuric acid group or a halogen atom. And n is 1 when X is a sulfuric group and n is 1 when X is a halogen atom. When n is 2, it is as mentioned above that R may be same or different. In view of the yield of the synthesis reaction and the ease of handling, R is preferably the same alkyl group. The alkyl group may be any linear, branched or cyclic. Although carbon number which an alkyl group has is not specifically limited, Preferably it is 1-8 pieces, More preferably, it is 1-4 pieces, 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, An octyl group, a nonyl group, a decyl group, a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, etc. are mentioned. Alkyl groups other than these may be used. Examples of the amine salt 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 hydrofluoric acid salt (CH ₃ CH ₂ NH ₃ F), ammonium sulfate ((NH ₄ ) ₂ SO ₄ ), monomethylamine sulfate ((CH ₃ NH ₃ ) ₂ SO ₄ ).

What is necessary is just to select the boron hydride alkali and amine salt to be used according to the structure of the borazine compound synthesize | combined. For example, when manufacturing N-methylborazine in which the methyl group is couple | bonded with the nitrogen atom which comprises a borazine ring, what is necessary is just to use the amine salt in which R is a methyl group, such as monomethylamine hydrochloride, as an amine salt. .

Although the mixing ratio of boron hydride alkali and an amine salt is not specifically limited, When the usage-amount of an amine salt is 1 mol, it is preferable to make the usage-amount of a boron hydride alkali 1-1.5 mol.

Although it does not restrict | limit especially as a solvent for synthesis | combination, For example, 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 of boron hydride alkali and an amine salt are not specifically 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. If it reacts in the said range, control of the hydrogen generation amount will be easy. The reaction temperature can be measured using a temperature sensor such as K thermocouple.

On the other hand, the alkyl borazine compound is a halogenated borazine compound such as B, B ', B "-trichloro-N, N', N" -trialkyl borazine as a starting material, using a Grigna reagent. It can be synthesized by substituting an alkyl group for the chlorine atom of the compound (see DTHOWORTH and LFHOHNSTEDT, J. Am. Chem. Soc., 82, 3860 (1960)).

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

What is necessary is just to determine the magnitude | size and kind of a distillation purification apparatus according to an environment and a scale. For example, if a large amount of borazine compound is to be treated, an industrial scale distillation column can be used. If a small amount of borazine compound is to be treated, distillation purification using a distillation tube can be used. For example, as a specific example of a distillation apparatus for treating a small amount of borazine compound, a distillation apparatus in which a Liebig cooling tube is provided in a three-necked flask as a Klaisen-type connecting tube can be used. However, the technical scope of this invention is not limited to embodiment using such a distillation apparatus.

The temperature at the time of distillation purification is not particularly limited and may be appropriately set according to the type of the borazine compound synthesized. For example, it is about 100-150 degreeC normally.

[Filtration step]

Then, the borazine compound prepared above is filtered. Thereby, it can separate with an impurity, and a borazine compound is refine | purified further and manufacture of a purified borazine compound is completed.

In the manufacturing method of this aspect, this filtration step is performed in the atmosphere whose water content is below a predetermined value.

Specifically, the moisture content of the atmosphere is 2000 volume ppm or less, preferably 1000 volume ppm or less, more preferably 500 volume ppm or less, still more preferably 100 volume ppm or less, particularly preferably 10 volume ppm or less Most preferably, it is 1 volume ppm or less. As described above, when the borazine compound is weak in water and has a high moisture content in the atmosphere, the borazine compound may be decomposed by contact with moisture, and impurities may be mixed in the borazine compound. Therefore, according to the present invention, decomposition of the borazine compound by contact with moisture can be suppressed, and the purification efficiency of the borazine compound can be improved. As the method of setting the moisture content of the atmosphere to 2000 ppm or less, for example, a method of substitution by a dew point managed gas may be used. In addition, as a value of the moisture content of the atmosphere in which the filtration step is performed, the value measured by the method employ | adopted in the Example mentioned later shall be employ | adopted.

Moreover, in this invention, it is preferable that the cleanliness of an atmosphere is also controlled below predetermined value.

Here, the "clean degree" means the number of foreign matters having a size of 0.1 μm or more per cubic foot (1 ft ³ ). In the first production method of the present invention, the filtration step, the number of foreign matters having a size of 0.1 μm or more present per 1 ft ³ is preferably 1000 or less, more preferably 100 or less, even more preferably 10 or less Especially preferably, it is performed in one or less atmospheres. Here, as the method of setting the cleanliness of the atmosphere to 1000 or less, for example, a method of air filtration using a filter can be used. In addition, as a cleanliness value of the atmosphere performed at the filtration stage, the value measured by the method employ | adopted in the Example mentioned later shall be employ | adopted.

The specific form of the atmosphere in which the filtration step is performed is not particularly limited, but the filtration step is preferably performed under an inert gas atmosphere such as rare gas such as argon or nitrogen.

In the filtration step, there is no particular limitation as to the specific form of the filtration means used to obtain the purified borazine compound. For example, the form which refine | purifies a borazine compound using a filtration filter is mentioned. At this time, the eye size of the filtration filter is not particularly limited, but is preferably 0.01 to 1 m, more preferably 0.1 to 0.5 m. When the eye size of the filtration filter is too small, there is a risk of causing a blockage immediately and the filtration step may not proceed smoothly. On the other hand, when the eye size of a filtration filter is too big | large, there exists a possibility that the impurity in a compound may not fully be removed. There is no restriction | limiting in particular also about the constituent material of a filtration filter, It is preferable that a filtration filter is comprised from resin from a viewpoint that mixing of impurities can fully be suppressed. As a resin material which comprises a filtration filter, polytetrafluoroethylene (PTFE), polypropylene, etc. are mentioned, for example. Among them, PTFE can be preferably used as a constituent material of the filtration filter from the viewpoint of effectively suppressing the incorporation of organic impurities.

There is no restriction | limiting in particular also about the flow rate of the borazine compound at the time of filtering through a filtration filter. However, preferably 0.01 ~ ³ to 1000cm / sec, and more preferably 1 ~ 100cm ³ / sec. If this flow rate is too small, there is a fear that the filtration time becomes long and the manufacturing cost increases. On the other hand, when this flow rate is too big | large, there exists a possibility that mixing of impurities may not fully be suppressed.

Another aspect of the present invention relates to a technique for suppressing the incorporation of impurities during filling of a borazine compound into a container. Specifically, the above aspect is a method for filling borazine compounds having a filling step of filling the borazine compounds in a container under an atmosphere having a water content of 2000 vol ppm or less.

In the filling method of this embodiment, the bored compound is filled in the container under atmospheric conditions having a predetermined water content. Thereby, incorporation of impurities in the filling of the borazine compound can be effectively suppressed.

Subsequently, the filling method of this embodiment will be described in detail in the order of steps.

[Prepared Compound Preparation Step]

First, the borazine compound to be filled is prepared. As for the specific form of preparing the borazine compound and the specific form of the borazine compound prepared thereby, the form described in the section of [Burazine Compound Preparation Step] of the above-described production method can be similarly employed. The detailed description is omitted.

In this step, preferably, the purified borazine compound prepared by the above-described preparation method is prepared. By using this purified borazine compound, the amount of impurities in the borazine compound to be filled can be further reduced.

[Charge stage]

Subsequently, the borazine compound prepared above is filled in a container. In the filling method of this embodiment, this filling step is carried out in an atmosphere having a water content of 2000 vol ppm or less. In addition, regarding the specific preferable form of the atmosphere in which the filling step is performed, since the form described in the [filtration step] column of the manufacturing method of the form mentioned above can be employ | adopted similarly, detailed description is abbreviate | omitted here.

In the filling step, there is no particular limitation as to the specific form of the container in which the borazine compound is filled. As for the constituent material of the container, for example, a metal material such as stainless steel or HASTELLOY, a plastic material such as PTFE, or the like can be employed. Especially, it is preferable that a container is comprised from stainless steel from a viewpoint of excellent sealing property. Moreover, it is preferable that a container can be sealed from a viewpoint of suppressing incorporation of an impurity more effectively, As a means which can seal a container, the form which provides a valve in a part of container, for example is illustrated.

In the filling step, there is no particular limitation as to the specific form of the filling means used for filling the borazine compound. For example, the form which charges a borazine compound by the pressurization of a borazine compound from the tank in which the borazine compound was preserve | saved is mentioned. There is no restriction | limiting in particular also about the filling rate at the time of filling a container with a borazine compound in a container. However, Preferably it is 0.1-100 cm <^3> / sec, More preferably, it is 1-10 cm <^3> / sec. If the charging speed is too slow, the charging time may be long and the manufacturing cost may increase. On the other hand, when this filling speed is too fast, there exists a possibility that exchange of a container for filling may become difficult.

According to the production method or the filling method of the present invention, a purified borazine compound having a reduced amount of impurities can be provided. That is, this invention also provides the refined borazine compound by which content of the impurity was reduced. At this time, content of the impurity in the refined borazine compound provided by this invention is 100 piece / mL or less, Preferably it is 50 piece / mL or less, More preferably, it is 10 piece / mL or less. "Impurity" means here the foreign matter (material other than a bored compound) which has a particle diameter of 0.5 micrometer or more. It goes without saying that the smaller the impurity content in the resulting purified borazine compound, the better. However, the technical range of the manufacturing method of the above-mentioned aspect of this invention is not limited only to the aspect which manufactures the refined borazine compound containing this amount of impurity. In some cases, a purified borazine compound containing an amount of impurities outside this range may be produced. Moreover, the technical range of the refined borazine compound with a small amount of such impurities is not limited only to the refined borazine compound manufactured by the manufacturing method of the above-mentioned aspect of this invention, and may be manufactured by other manufacturing methods depending on the case. It may be. In addition, as content of the impurity in the manufactured refined borazine compound, the value measured by the method as described in the Example mentioned later shall be employ | adopted.

According to still another aspect of the present invention, there is provided a container for storing a borazine compound having a pressure resistance of 0.1 MPa or more. By preserving the borazine compound in such a container, when the borazine compound is preserved, outside air containing water vapor is prevented from entering the storage container, and decomposition of the borazine compound in storage can be effectively prevented.

The term "preservation" of the borazine compound is a concept including any point from the time point at which the compound is filled to the storage container after the synthesis of the borazine compound to the point of use for any particular application. Therefore, not only the case where the borazine compound is stored in the warehouse in the state filled in the container, but also the case where it is transported by the truck etc. according to shipment, is also included in the concept of "conservation" in this invention. In addition, although a borazine compound may be preserve | saved independently in a storage container, you may be preserve | saved in a storage container in the state melt | dissolved in a suitable solvent etc. depending on a case.

As described above, the internal pressure of the container for storage of the present embodiment is 0.1 MPa or more, preferably 0.2 MPa or more, and more preferably 0.3 MPa or more. Moreover, when the internal pressure of a container is less than 0.1 MPa, the atmosphere at the time of storage of a borazine compound flows in into a container, and there exists a possibility that a borazine compound may decompose by contact with the moisture contained in an atmosphere. In addition, as a value of the internal pressure of the container used for storing a borazine compound, the value measured by the method employ | adopted in the Example mentioned later shall be employ | adopted.

"Pressure pressure" means a time point at which the atmosphere can flow into the container when the sealed container is placed under an atmosphere having a certain initial pressure (herein referred to as 0.1 MPa) and the pressure of the atmosphere is increased. The pressure is obtained by subtracting the initial pressure (0.1 MPa) from the atmospheric pressure. That is, when the pressure of the atmosphere exceeds "inner pressure + initial pressure (0.1 MPa)", the atmosphere can flow into the container. Therefore, in the present invention, when preserving the borazine compound in an atmosphere having an initial pressure of 0.1 MPa (nearly equal to atmospheric pressure), the borazine compound is contained in a container in which the atmosphere is not introduced even if the pressure of the atmosphere is 0.2 MPa or more. It is to save.

Here, from the viewpoint of preventing the inflow of the storage atmosphere into the storage container, the upper limit of the internal pressure pressure of the storage container is not particularly limited. However, from the viewpoint of ease of handling such as the weight of the container, the internal pressure pressure of the container for storage is preferably 2.0 MPa or less, and more preferably 0.5 MPa or less. However, forms outside this range may also be employed.

There is no restriction | limiting in particular about the specific form, such as the size and material of a storage container. To store small amounts of borazine compounds synthesized at the laboratory level, small preservation containers can be used. In addition, in order to preserve the large amount of borazine compound synthesize | combined at the industrial level, you may use a big container for storage.

As for the material of the storage container, for example, a metal material such as stainless steel or hastelloy, a plastic material such as polytetrafluoroethylene (PTFE), or the like can be adopted. Especially, it is preferable that a container is comprised from stainless steel from a viewpoint of high pressure resistance. Moreover, what is necessary is just to coat the inner surface of the container which consists of materials, such as said metal, with resin for the purpose of further improving the corrosion resistance of a storage container. At this time, the resin used for coating is not particularly limited, but examples thereof include polytetrafluoroethylene (PTFE), polypropylene, and the like. Especially, it is preferable to coat using PTFE from a viewpoint of the outstanding effect of improving corrosion resistance. Although there is no restriction | limiting in particular about the coating thickness of resin coating, Preferably it is 10-3000 micrometers, More preferably, it is 500-1000 micrometers.

Moreover, it is preferable that the container for storage is sealable, and the form which provides a valve in a part of container as an example of a means which enables sealing of a container is illustrated.

In addition, regarding the storage temperature condition at the time of preserving a borazine compound using the storage container of this form, since stability with respect to the temperature differs according to the kind of borazine compound, it cannot be uniquely prescribed | regulated, Suitable temperature conditions may be appropriately selected to maintain the desired purity. However, the borazine compound is preferably stored under a temperature condition of preferably 30 ° C. or lower, more preferably 25 ° C. or lower. When the temperature at the time of storing a borazine compound exceeds 30 degreeC, there exists a possibility that the impurity in a borazine compound may increase. In particular, when the R ₂ group in the formula (1) is a hydrogen atom or a lower alkyl group having 1 to ₂ carbon atoms, this problem tends to be remarkably expressed. In the above-mentioned aspect, it is most preferable that the temperature condition at the time of storage becomes 30 degrees C or less over the whole period from the start of storage to the end, but it is not limited only to this form, At least one of the periods from the start of storage to completion. At this time, preferably 80% or more of the period, more preferably 90% or more of the period, the temperature condition at the time of storage should be 30 degrees C or less.

According to the storage container of this embodiment and the storage method using the same, decomposition of the borazine compound at the time of storage can be suppressed, and the purity fall of the borazine compound can be prevented at a very low ratio. That is, this invention also provides the borazine compound by which the fall of purity was suppressed. At this time, the purity reduction when the borazine compound provided by the present invention is stored at 25 ° C. for 60 days is preferably 1% by mass or less, more preferably 0.1% by mass or less, even more preferably. 0.01 mass%. In addition, the "purity reduction of a borazine compound is 1 mass%", for example, when the purity of the borazine compound at the start of storage is 99.8 mass%, the purity of a borazine compound after 60 days storage at 25 degreeC 98.8 mass%. That is, "purity fall" means the fall of the absolute purity of the borazine compound, not the relative value before and after storage. In addition, as a purity value of a borazine compound, the value measured by the method employ | adopted in the Example mentioned later shall be employ | adopted.

The borazine compound is not particularly limited, but may be used for forming low dielectric constant films such as an interlayer insulating film for semiconductors, a barrier metal layer, and an etch stopper layer. In that case, N-alkyl borazine may be used and the compound which modified | denatured to N-alkyl borazine may be used. The polymer obtained by polymerizing N-alkyl borazine or a derivative of N-alkyl borazine may be used as a raw material for an interlayer insulating film, barrier metal layer or etch stopper layer for semiconductors.

The polymer may be formed using a compound having a borazine ring skeleton as a monomer. The polymerization method and the polymerization form are not particularly limited. The polymerization method is selected by the functional group bonded to the borazine ring. For example, when an amino group is bonded, the polymer can be synthesized by condensation polymerization. When the borazine ring is bonded to a vinyl group or a functional group including a vinyl group, the polymer may be formed by radical polymerization using a polymerization initiator. The polymer may be a homopolymer or a copolymer composed of two or more monomer units. The form of the copolymer may be any of a random copolymer, a block copolymer and a graft copolymer. When the monomer which has three or more functional groups which can form a bond with another monomer is used, it is also possible to obtain the polymer which the monomer couple | bonded in network form.

Subsequently, a method of forming an interlayer insulating film, a barrier metal layer, or an etch stopper layer for a semiconductor will be described. In addition, in the following description, "a borated compound", "a derivative of a borazine compound", and a "polymer resulting from these" are collectively called "a borated ring containing compound."

In order to form the interlayer insulation film, barrier metal layer, or etching stopper layer for a semiconductor using a borazine ring containing compound, the method of preparing the coating film by preparing the solution form or slurry form containing a borazine ring containing compound, and apply | coating this This can be used. The solvent for dissolving or dispersing the borazine ring-containing compound used at that time is not particularly limited as long as it is capable of dissolving the borazine ring-containing compound and other components added as necessary. As a solvent, For example, Alcohol, such as ethylene glycol and ethylene glycol monomethyl ether; Aromatic hydrocarbons such as toluene, benzene and xylene; Hydrocarbons such as hexane, heptane and octane; Tetrahydrofuran, diglyme, tetraglyme and the like can be used. These may be used individually by 1 type and may mix and use 2 or more types. In the case of film formation using spin coating, diglyme is preferable. Use of diglyme or a derivative thereof as a solvent improves the uniformity of the film to be produced. In addition, cloudiness of the membrane can be prevented. The amount of the solvent for dissolving or dispersing the borazine ring-containing compound is not particularly limited and may be determined depending on the means for producing the low dielectric material. For example, when forming into a film by spin coating, what is necessary is just to determine a solvent and an amount of solvent so that it may become a viscosity suitable for spin coating.

The composition containing the borazine ring containing compound is supplied to a desired site, dried and solidified. For example, in order to form the interlayer insulation film for semiconductors, what is necessary is just to apply | coat and dry on a board | substrate by spin coating. If the coating having a desired thickness cannot be obtained by one coating and drying, the coating and drying may be repeated until the desired thickness is obtained. Film-forming conditions, such as the rotation speed of a spin coater, drying temperature, and drying time, are not specifically limited.

Application | coating to a board | substrate may use methods other than spin coating. For example, spray coating, dip coating or the like can be used.

Thereafter, the coating film is dried. The drying temperature of a coating film is about 100-250 degreeC normally. The dry temperature here means the maximum temperature of the temperature at the time of a drying process. For example, the drying temperature is gradually raised and held at 100 ° C for 30 minutes, and then the drying temperature when cooled is 100 ° C. The firing temperature can be measured using a thermocouple. The drying time of the coating film is not particularly limited. What is necessary is just to determine suitably, considering characteristics, such as permittivity and moisture resistance with respect to the obtained low dielectric constant material.

EMBODIMENT OF THE INVENTION Hereinafter, although an Example and a comparative example are described in detail embodiment of this invention, the technical scope of this invention is not limited to the following form.

<Example 1-1>

Methylamine hydrochloride (33.5 g) which is an amine salt dehydrated while nitrogen-substituting, and triglyme (98.6g) which is a solvent were put into the reaction container provided with the cooler, and the reaction system was heated up to 100 degreeC.

On the other hand, sodium borohydride (21.0 g) which is a borohydride alkali was prepared, and this was added to triglyme (88.7 g) prepared separately, and the slurry was prepared.

The prepared slurry of sodium borohydride was slowly added to the reaction vessel heated to 100 ° C over 1 hour.

After completion | finish of slurry addition, the reaction system was heated up to 200 degreeC over 2 hours, and also aged at 200 degreeC for 2 hours, and synthesize | combined N, N ', N "-trimethyl borazine.

The obtained N, N ', N "-trimethyl borazine was distilled at 150-220 degreeC, and N, N', N" -trimethyl borazine was refine | purified.

Purified N, N ', N "-trimethyl borazine was filtered using a 0.1 μm filtration filter made of polytetrafluoroethylene (PTFE) under a nitrogen atmosphere at 23 ° C., a cleanliness of 500, and a water content of 127 vol ppm. , N, N ', N "-trimethyl borazine were further purified. In addition, the cleanliness of the atmosphere was measured using a particle counter (manufactured by Leon Co., Ltd .; KC-03A1), and the moisture content was measured using an online dew point meter (manufactured by Nagano Electric Industries, Ltd.) (Examples below) Same also in). Furthermore, filtered N, N ', N "-trimethyl borazine was filled in the stainless container which can be sealed by a valve.

The number of impurities with a particle size of 0.5 µm or more contained in the purified N, N ', N "-trimethyl borazine packed in the container was counted by a particle counter (made by Particle Measuring Systems Inc. (PMS); LIQUIL AZ-S02-). HF) was used to determine 46 pieces / mL, and the purity of the filled tablets N, N 'and N "-trimethyl borazine was measured to be 99.9% by mass. In addition, the purity of the borazine compound was measured using gas chromatography. Measurement conditions are as follows.

Apparatus: GC-14B manufactured by Shimadzu Corporation

Column: Hitachi Science Systems, Inc. Ultra Alloy (8H)

Carrier Gas: Nitrogen

Carrier gas flow rate: 3.0 mL / min

Sample injection temperature: 300 ° C

Detector temperature: 300 ℃

Sample injection volume: 0.2 μL

Column temperature: Temperature rise to 250 degreeC at a temperature increase rate of 50 degreeC (5 minutes) → 20 degreeC / min.

           → Temperature rise to 300 degrees Celsius at temperature increase rate of 10 degrees Celsius / minute → 300 degrees Celsius (10 minutes)

<Example 1-2>

N, N 'and N "-trimethyl borazine were synthesize | combined by the method similar to the said Example 1-1, and it refine | purified by distillation.

Purified N, N ', N "-trimethyl borazine was filtered using a 0.1 μm filtration filter made of PTFE under a nitrogen atmosphere of 23 ° C., a cleanliness of 10, and 1 vol ppm of water content. "-Trimethyl borazine was further purified. Furthermore, filtered N, N ', N "-trimethyl borazine was filled in the stainless container which can be sealed by a valve.

The number of impurities having a particle size of 0.5 µm or more contained in the purified N, N ', N "-trimethyl borazine packed in the container was measured using a particle counter (manufactured by PMS; LIQUIL AZ-S02-HF), and the concentration was 10 / mL or less. Moreover, the purity of the filled tablets N, N ', and N "-trimethyl borazine was measured and found to be 99.9 mass%.

<Example 1-3>

In the same manner as in Example 1-1, N, N ', and N "-trimethyl borazine were synthesized and purified by distillation.

Purified N, N ', N "-trimethyl borazine was filtered using a 0.1 μm filtration filter made of PTFE under a nitrogen atmosphere of 23 ° C., a cleanness of 50000, and a water content of 127 parts by volume ppm, and N, N ′, N "-Trimethyl borazine was further purified. In addition, filtered N, N ', N "-trimethyl borazine were filled in the stainless container which can be sealed by a valve.

The number of impurities with a particle size of 0.5 μm or more contained in the purified N, N ′, N ″ -trimethyl borazine packed in the container was measured using a particle counter (manufactured by PMS; LIQUIL AZ-S02-HF), and the content was 73 / mL or less. Moreover, the purity of the filled tablets N, N ', N "-trimethyl borazine was measured and found to be 99.8 mass%.

Comparative Example 1

N, N ', and N "-trimethyl borazine were synthesize | combined by the method similar to the said Example 1-1, and it refine | purified by distillation.

Purified N, N ', N "-trimethyl borazine was filtered using a 0.1 μm filtration filter made of PTFE under a nitrogen atmosphere of 23 ° C., a cleanness of 50000, and a water content of 2570 vol ppm, yielding N, N ′, N ″. Trimethyl borazine was further purified. Furthermore, filtered N, N ', N "-trimethyl borazine was filled in the stainless container which can be sealed by a valve.

The number of impurities having a particle size of 0.5 μm or more contained in the purified N, N ′, N ″ -trimethyl borazine packed in the container was measured using a particle counter (manufactured by PMS; LIQUIL AZ-S02-HF), and 3000 / mL Moreover, when the purity of the filled tablet N, N ', N "-trimethyl borazine was measured, it was 97.5 mass%.

From the results shown in Examples 1-1 to 1-3 and Comparative Example 1, the borazine compound was filtered to purify the borazine compound under an atmospheric condition of a predetermined water content, and filled into a vessel under an atmospheric condition of a predetermined water content to obtain a borazine compound. It has been shown that the incorporation of impurities can be effectively suppressed.

Therefore, according to one embodiment of the present invention, the quality of the use (for example, an interlayer insulating film for semiconductor) in which a borazine compound is used can be further improved.

<Example 2-1>

Methylamine hydrochloride (33.5 g) which is an amine salt dehydrated while nitrogen-substituting, and triglyme (98.6g) which is a solvent were put into the reaction container provided with the cooler, and the reaction system was heated up to 100 degreeC.

On the other hand, sodium borohydride (21.0 g) which is a borohydride alkali was prepared, and this was added to triglyme (88.7 g) prepared separately, and the slurry was prepared.

The prepared slurry of sodium borohydride was slowly added to the reaction vessel heated to 100 ° C over 1 hour.

After completion | finish of slurry addition, the reaction system was heated up to 200 degreeC over 2 hours, and also aged at 200 degreeC for 2 hours, and synthesize | combined N, N ', N "-trimethyl borazine.

The obtained N, N ', N "-trimethyl borazine was distilled at 150-220 degreeC, and N, N', N" -trimethyl borazine was refine | purified. The purity of the obtained purified N, N ', N "-trimethyl borazine was 99.8 mass%. The purity of the borazine compound was measured using gas chromatography. The measurement conditions were the same as in Example 1-1. same.

As a container for storing the borazine compound, a stainless container having an inner surface coated with PTFE (coating thickness: 500 µm) was prepared. It was 0.2 MPa when the internal pressure of the prepared storage container was measured. At this time, the internal pressure of the container for storage is measured by providing a leak valve to the container, filling the nitrogen gas into the container at 23 ° C, and starting the leak through the leak valve from the container. Was measured by using a pressure gauge and calculated by subtracting the atmospheric pressure from the measured value.

The tablets N, N ', and N "-trimethyl borazine obtained above were filled and sealed in the prepared storage container, and were stored for 60 days at 25 degreeC in the state which pressurized by 0.1 MPa with nitrogen gas. N, N' after storage , N ″ -trimethyl borazine was measured for purity of 99.8% by mass, and no decrease in purity of the borazine compound was observed.

<Example 2-2>

In a reaction vessel equipped with a cooler, B, B ', B "-trichloro-N, N', N" -trimethyl borazine (41.2 g), which is a halogenated borazine compound, and diethyl ether as a solvent (substituting with nitrogen) 80 g) was added and diethyl ether solution of ethyl magnesium bromide (3M, 200 mL) was added dropwise at 20 ° C over 3 hours. Thereafter, the mixture was aged at reflux for 2 hours, and the reaction solution was cooled to room temperature, and then impurities were filtered out by filtration.

Diethyl ether was ligated from the filtrate obtained by the above filtration, the filtrate was further filtered, and the filtrate was distilled under reduced pressure to obtain B, B ', B "-triethyl-N, N', N" -trimethyl borazine. Purified. It was 99.5 mass% when the purity of obtained tablet B, B ', B "-triethyl-N, N', N" -trimethyl borazine was measured by the same method as the said Example 1-1.

The tablets B, B ', B "-triethyl-N, N', and N" -trimethyl borazine obtained above were charged and sealed in the same storage container as in Example 2-1 and sealed with nitrogen gas. It stored for 60 days at 25 degreeC in 0.1 MPa pressurized state. When the purity of B, B ', B "-triethyl-N, N', and N" -trimethyl borazine after storage was measured, it was 99.5 mass%, and no purity reduction of the borazine compound was observed.

<Example 2-3>

B, B ', B "-triethyl-N, N', and N" -trimethyl borazine were synthesized and purified in the same manner as in Example 2-2, except that the temperature conditions at the time of storage were set to 60 degreeC. And preserved. When the purity of B, B ', B "-triethyl-N, N', and N" -trimethyl borazine after storage was measured, it was 98.8 mass%, and the purity fall of 0.7 mass% borazine compound was observed.

Comparative Example 2

N, N 'and N "-trimethyl borazine were synthesize | combined by the method similar to the said Example 2-1, and it refine | purified by distillation.

As a container for storing the borazine compound, a stainless container having an inner surface coated with PTFE (coating thickness: 500 µm) was prepared. When the internal pressure of the prepared storage container was measured, it was 0.05 MPa.

The obtained tablets N, N 'and N "-trimethyl borazine were filled and sealed in the prepared storage container, and were stored for 60 days at 35 degreeC. The purity of N, N' and N" -trimethyl borazine after storage was measured. As a result, a decrease in purity of 95.1 mass% and 4.7 mass% of the borazine compound was observed.

From the results shown in Examples 2-1 to 2-3 and Comparative Example 2 above, it is shown that decomposition of the borazine compound can be effectively suppressed by storing the borazine compound in a storage container having a predetermined internal pressure. In addition, it appears that the reduction in purity of the borazine compound can be more effectively suppressed by carrying out the storage under predetermined temperature conditions.

Therefore, according to another form of this invention, the quality of the use (for example, the interlayer insulation film for semiconductors) in which a borazine compound is used can be improved further.

This application is based on Japanese Patent Application No. 2005-241389 for which it applied on August 23, 2005, and Japanese Patent Application No. 2005-250074 for which it applied on August 30, 2005, The indication is referred to It is quoted as a whole by.

Claims (12)

A borazine compound preparation step of preparing a borazine compound in a liquid state, Distilling the prepared borazine compound in a liquid state, The distilled liquid borazine compound has a filtration step of obtaining a borazine compound having a purity of 99.8% by mass or more by filtering under atmospheric conditions of 2000 vol ppm or less of water content, wherein the borazine compound is represented by the following Chemical Formula 1 Preparation of Purified Borazine Compounds: [Formula 1]

In formula, each R <_1> and each R <_2> may be same or different, respectively, and is a hydrogen atom or a C1-C8 alkyl group. The method of claim 1, wherein the filtration step is performed in an atmosphere having a cleanness of 1000 or less. delete delete delete delete delete delete delete delete delete delete