JP3021412B2 - Gas storage / delivery method and gas storage / delivery device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for storing and delivering hydride or halide gas such as arsine, phosphine and boron trifluoride used for ion implantation gas in the semiconductor industry, for example. More specifically, the present invention relates to a gas storage / supply method and apparatus excellent in stably and safely adsorbing and storing a considerable amount of the gas with high purity for a long period of time and transmitting the gas safely while suppressing release of the gas to the atmosphere.

[0002]

2. Description of the Related Art For example, in the semiconductor industry, arsine (As)
H ₃ ), phosphine (PH ₃ ), boron trifluoride (BF
Gases that are extremely toxic to the human body, such as ₃ ), are widely used for purposes such as being used in ion implantation processes for semiconductor manufacturing. Typically, arsine is conveniently supplied for these commercial applications by cylinders or cylinders containing either pure arsine or a mixture of hydrogen or arsine with a balance gas such as helium. Leakage of these arsine-containing cylinders is potentially very dangerous, especially during transport and shipping of these cylinders. In order to solve this problem, a method of adsorbing arsine on zeolite, which is a porous crystalline alumina silicate, and storing it under negative pressure is disclosed in, for example, US Pat. No. 4,744,421 issued May 17, 1988. Have been. According to this method, arsine once adsorbed on zeolite under negative pressure is desorbed from zeolite as a reversible reaction,
When delivered to the required site, such negative pressure can avoid the danger of toxic arsine diffusing into the atmosphere.

However, when zeolite is used, arsine is decomposed into arsenic and hydrogen at room temperature, so that the concentration of pure arsine that can be taken out decreases, and the internal pressure of the cylinder increases due to hydrogen generated over time. In some cases, the pressure becomes higher than the atmospheric pressure, and there is a risk that arsine leaks to the outside.

In order to avoid these dangers, PCT W
O96 / 11739 discloses that activated carbon with few impurities is suitable for storing gaseous compounds such as arsine, phosphine and boron trifluoride used as ion implantation gas in the semiconductor industry. However, since activated carbon is generally made of natural products such as coconut shell and coal, if pores are formed in the activation step, which is one of the production processes of activated carbon, the influence of impurities present in the raw material, Due to the inhomogeneity of the composition and structure, the pore size distribution was widened, which was inappropriate for efficiently adsorbing and storing a specific gaseous compound. Furthermore, raw materials have lot-to-lot differences derived from the place of production, the time of collection, and the like, so that it is difficult to strictly control the pore size distribution.

If the activated carbon particles packed in the cylinder do not have a sufficiently high strength, the activated carbon particles may rub against each other or between the activated carbon particles and the cylinder wall surface due to pressure fluctuations generated during the movement of the cylinder and the adsorption and desorption of gas. Because
Activated carbon deteriorates, carbon fines are generated in the cylinder, and there is a problem that the carbon fine particles are clogged in a filter of a gas filter through which a gaseous compound is taken out from the cylinder.

[0006] Activated carbon derived from natural products contains various metals as impurities. If these metals are contained and used for adsorption and storage of arsine, phosphine, etc., for example, arsine becomes arsenic and hydrogen as shown in the following formula. The adsorbed gaseous compound is decomposed as in the case where the above-mentioned zeolite is used as the adsorbent. AsH ₃ → As + 3 / 2H ₂

[0007] Along with this, first, the concentration of pure arsine that can be taken out at the time of delivery decreases. Second, with the passage of time, the pressure inside the cylinder increases due to the generated hydrogen,
In some cases, the pressure may be higher than the atmospheric pressure from the initial negative pressure,
At the time of delivery, there is a danger that highly toxic gas such as arsine leaks out.

Therefore, in general, washing with an acid such as hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid or the like is performed to increase the purity of the activated carbon. However, when acid cleaning is performed, anions of the substance used for acid cleaning may remain on the activated carbon, and when these activated carbons are used for adsorption storage of arsine, phosphine, etc., these anions are reduced and nitrogen gas, oxygen gas As in the case described above, problems such as a decrease in the purity of the stored gas and gas leakage may occur.

In the case of using a high-purity activated carbon produced from a high-purity raw material, for example, although the problem that arsine is decomposed into arsenic and hydrogen is avoided, the high-purity activated carbon and arsine are not used. the gas reacts, hydrogen, nitrogen,
Generates impurities such as carbon monoxide and carbon dioxide. Unlike the hydrogen gas generated by self-decomposition such as arsine described above, the impurity gas generated in this case usually does not reach a gas pressure in the storage vessel higher than the atmospheric pressure, and at that point, the external environment at the time of delivery is reduced. Although there is little risk of leakage to the atmosphere, arsine, phosphine, boron trifluoride, etc., are used, for example, in the semiconductor industry in ion implantation processes, such as SEMIInterna.
According to Tional Standards (1990), since the required purity is at least 99.9% or more, a decrease in the purity of the gas may significantly impair the value of these gases.

[0010] Further, while controlling the flow rate, a specific hydride gas and a halogenated compound gas used for the production of semiconductors which are adsorbed and stored under normal working environment temperature are suctioned, desorbed and sent out using a vacuum pump while controlling the flow rate. In such a case, depending on the flow rate of the gas and / or the performance of the vacuum pump, a considerable amount of the gas eventually remains in the container, and the amount of the gas that can be effectively used is limited.

[0011]

DISCLOSURE OF THE INVENTION The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, completed the present invention. It is an object of the present invention to provide a method and an apparatus for adsorbing well, storing the gas safely and stably, and sending the gas safely and efficiently while suppressing release of the gas to the atmosphere.

[0012]

In the present invention, in order to solve the above-mentioned problems, a predetermined amount of a hydrogenated compound or a halogenated compound gas is brought into contact with activated carbon mainly composed of a phenol resin, A method was developed in which the activated carbon was adsorbed and stored in a storage environment under atmospheric pressure and stored, and at least a part of the adsorbed gas was desorbed and sent to the working environment.

Further, in the present invention, a predetermined amount of a hydride compound or a halogenated compound gas to be used is brought into contact with activated carbon containing a phenol resin as a main raw material, and is adsorbed to the activated carbon under a storage environment at atmospheric pressure or lower. A device was developed that desorbs at least a portion of the stored and adsorbed gas and delivers it to the working environment.

[0014] In the present invention, the activated carbon mainly composed of phenol resin used in the method and apparatus is a granular carbon molded product obtained by combining carbonized and activated particles of phenol resin powder, and has a specific surface area. 700-15
00 m ² / g, pore volume of pore diameter 0.01 to 10 μm is 0.1 to 1.0 cc / g, pore volume of pore diameter 10 nm or less is 0.20 to 0.80 cc / g, And a pore diameter 0.6 to a pore volume of 10 nm or less.
The ratio of the pore volume of 0.8 nm is 75 vol% or more, the particle bulk density is 0.4 to 1.1 g / cc, and the packing density is 0.3.
A method and an apparatus using activated carbon, characterized in that the activated carbon particles are 0 to 0.70 g / cc, the ash content is 1.0% or less, and the tensile strength of the activated carbon particles is 30 kg / cm ² or more.

Further, in the present invention, an adsorption step of preliminarily contacting and adsorbing a hydrogenated compound and a halogenated compound gas in an enclosed space, a step of accelerating a system which has undergone the adsorption reaction, and a step of accelerating the reaction When the activated carbon is treated by a series of discharge steps of discharging the gas having passed through the step from the enclosed space to absorb and store a hydrogen compound and a halogenated compound gas of the same type or different from the gas, the activated carbon is removed. A method has been developed to prevent the purity of the stored gas from being reduced due to the impurity gas generated by the contact between the gas and the stored gas.

Further, in the present invention, an adsorption step of adsorbing a hydrogenated compound and a halogenated compound gas in advance by contacting them in a closed space, a step of accelerating the system after the adsorption reaction, and a step of accelerating the reaction When the activated carbon is treated by a series of discharge steps of discharging the gas having passed through the step from the enclosed space to absorb and store a hydrogen compound and a halogenated compound gas of the same type or different from the gas, the activated carbon is removed. A device has been developed to prevent the purity of the stored gas from being reduced due to the impurity gas generated by contact between the gas and the stored gas.

Further, in the present invention, the hydrogenated compound or halogenated compound gas used is brought into contact with activated carbon containing phenolic resin as a main raw material, and adsorbed on the activated carbon under a storage environment at atmospheric pressure or lower to store the gas. Then, the structure of the device for desorbing at least a part of the adsorbed gas and delivering it to the working environment increases the amount of stored gas that can be effectively used. We have developed a method or a device equipped with a heating unit with a temperature control function that can heat the activated carbon together.

[0018]

Embodiments of the present invention will be described below in detail.

In the present invention, a predetermined amount of a hydrogenated compound or a halogenated compound gas is brought into contact with activated carbon containing phenolic resin as a main raw material, and is adsorbed and stored on the activated carbon under a storage environment under atmospheric pressure. For desorbing at least a part of the gas and storing the hydride or halogenated compound gas, which is characterized by drawing a negative pressure in order to send it to the working environment, the device for sending the gas is, for example, FIG.
As shown in the figure, container 1, container valve 2, container valve built-in filter 3, upper space 4, purge valve 5, pressure gauge 6, bypass valve 7, line filter 8, air drive valve 9, mass flow controller 10, connection pipe 11 , Activated carbon 12. The device comprises at least a container 1 and activated carbon 12
And a unit for controlling the heating temperature may be provided at the same time. Further, it is preferable that the connection pipe 11 from the container 1 has sufficient vacuum tightness.

In the present invention, a predetermined amount of a hydrogenated compound or a halogenated compound gas is brought into contact with high-purity activated carbon,
Hydrogenation characterized in that it is adsorbed and stored on the activated carbon under a storage environment at atmospheric pressure or lower, and at least a part of the adsorbed gas is desorbed and reduced to a negative pressure in order to send it to the working environment. Activated carbon used in a method or an apparatus for storing a compound or a halogenated compound gas and then sending it out has a pore diameter and a pore volume that can be delicately controlled, and assures uniformity as a raw material and uniformity between lots. Activated carbon made of a superior phenol resin is preferred, and more preferably, a granular carbon molded product obtained by combining carbonized and activated particles of a phenol resin powder, having a specific surface area of 800 to 1500 m ² / g and a pore diameter of 0. The pore volume of 0.1 to 10 μm is 0.1 to 1.0.
cc / g, pore volume of 0.20 or less
0.80 cc / g, and the ratio of the pore volume of the pore diameter of 0.6 to 0.8 nm to the pore volume of the pore diameter of 10 nm or less is 75 vol% or more, and the particle bulk density is 0.4 to
1.1 g / cc, packing density 0.30 to 0.70 g / c
c, ash content is 1.0% or less, tensile strength of particles is 30k
g / cm ² or more.

More preferably, an adsorption step separately proposed in the present invention, in which a hydride compound such as arsine, phosphine and boron trifluoride and a halogenated compound gas are brought into contact in advance in a closed space and adsorbed. Activated carbon containing phenolic resin as a main raw material, which has been subjected to a series of steps of a step of promoting the reaction of the system that has undergone the adsorption reaction and a step of discharging the gas that has undergone the reaction promoting step from the closed space.

The specific surface area of the activated carbon is 700 to 1500 m
² / g, preferably 850 to 1400 m ² / g, most preferably 900 to 1300 m ² / g. When the specific surface area is less than 800 m ² / g, the amount of adsorption sites for gaseous compounds such as arsine, phosphine and the like is too small, and the adsorption capacity is undesirably low. In addition, the specific surface area is 1500 m
^{When the} content is ² / g or more, the pore diameter is considered to be effective for the adsorption of gaseous compounds such as arsine and phosphine.
The pore volume of nm is undesirably small.

The activated carbon has a pore volume of a pore diameter of 0.01 to 10 μm, preferably 0.1 to 1.0 cc / g, preferably 0.2 to 1.0 cc / g.
~ 0.8cc / g, most preferably 0.3-0.7cc
/ G. If the pore volume in this range is smaller than 0.1 cc / g, the diffusion rate of gaseous compounds such as arsine and phosphine in the pores becomes slow, and the adsorption rate and desorption rate are undesirably reduced. In addition, the pore diameter is 0.01 to 10 μm.
If the pore volume of m is larger than 1.0 cc / g, the bulk density of the particles and the mechanical strength of the particles become undesirably small.

The activated carbon has a pore volume of 0.20 to 0.80 cc / g having a pore diameter of 10 nm or less, and a pore diameter of 0.6 to 0.8 occupies the pore volume of a pore diameter of 10 nm or less.
The ratio of the pore volume of 8 nm is 75 vol% or more. The pore volume with a pore diameter of 10 nm or less is preferably 0.30
０．７0.70 cc / g, most preferably 0.30 to 0.6
0 cc / g. When the pore volume with a pore diameter of 10 nm or less decreases, the pore volume with a pore diameter of 0.6 to 0.8 nm also decreases, so that the adsorption capacity of gaseous compounds such as arsine and phosphine decreases. If the pore volume with a diameter of 10 nm or less is too large, the pore diameter is 0.6 to 0.8 nm.
Is unfavorable because the ratio of the pore volume decreases.

The pore volume with a pore diameter of 0.6 to 0.8 nm is 75 vol% of the pore volume with a pore diameter of 10 nm or less.
Or more, preferably 78 vol% or more, most preferably 8 vol%
0 vol% or more. Arsine (As H _3), phosphine emissions (PH ₃₎ with respect to the magnitude calculated by molecular mechanics structure of the molecule, the result of calculation using the van der Waals radius of each molecule, the long axes of the molecules Is 0.
The pores effectively acting to adsorb these molecules are pores having a diameter slightly larger than the molecular diameter, and the pore diameter is about 0.6 to 0.49 nm.
It is considered a 0.8 nm pore. If the pore diameter is too small relative to the size of the molecule, the rate of molecule adsorption is undesirably low. On the other hand, if the pore diameter is considerably large relative to the size of the molecule, the adsorption rate and the desorption rate both increase, which is undesirable because the equilibrium adsorption amount decreases.

Therefore, if the pore volume having a pore diameter of 0.6 to 0.8 nm, which effectively acts to adsorb these molecules, becomes smaller than 75 vol% of the pore volume having a pore diameter of 10 nm or less, arsine (AsH ₃₎ ), The adsorption capacity of gaseous compounds such as phosphine (PH ₃ ) is undesirably reduced.

The activated carbon has a particle bulk density of 0.4-1.
2 g / cc, preferably 0.5-1.0 g / cc, most preferably 0.6-0.8 g / cc. If the bulk density of the particles is too small, the adsorption capacity per internal volume of the container is undesirably reduced when the container is filled in a container such as a cylinder. Also,
If it is too large, the porosity of the activated carbon decreases, leading to a decrease in adsorption capacity, which is not preferable.

The packing density of the activated carbon in a container such as a cylinder is 0.3 to 0.7 g / cc, preferably 0.5 to 0.65 g / cc. If the packing density is too low, the adsorbing capacity per internal volume of a cylinder or the like decreases, which is not preferable. The shape of the activated carbon of the present invention is columnar, spherical, etc.,
Cylindrical or other irregular cross-sections can be used.

The size of the activated carbon particles is 0.3 to 5 m.
m, preferably 0.6-4 mm, most preferably 0.8
３3 mm. If the particles are too large, the filling density cannot be increased when the particles are filled in a container such as a cylinder, which is not preferable. If the particles are too small, the workability during the production of the particles and the filling operation into a cylinder or the like is poor, which is not preferable.

Further, for example, an adsorption step in which activated carbon is brought into contact with a hydrogenated compound such as arsine, phosphine or boron trifluoride or a halogenated compound gas in advance in a closed space to adsorb the activated carbon, and a reaction is carried out by reacting the system after the adsorption reaction. Accelerating;
A series of steps of a discharging step of discharging the gas having passed through the reaction promoting step from the closed space is performed on the activated carbon. The reason is that hydrogen, nitrogen, oxygen, and carbon atoms present on the pore surface of the activated carbon are forcibly removed in advance to prevent impurities from being mixed into the gaseous compound to be stored. The pre-injected gaseous compounds not only physically adsorb to the activated carbon surface, but also chemically react with hydrogen, nitrogen, oxygen and carbon atoms on the activated carbon surface, causing the generation of hydrogen, nitrogen, carbon monoxide and carbon dioxide. , Mixed into the previously injected gaseous compounds. Therefore, the number of atoms causing impurities generated by reacting with the gaseous compound to be stored in the activated carbon has been reduced, so that contamination of the gaseous compound to be stored with impurities can be avoided.

The reaction promoting step preferably includes a step of heating a predetermined amount of a gaseous compound such as arsine, phosphine or boron trifluoride in the closed space. The temperature in the heating step is preferably 30 ° C. or higher, which is a general use environment temperature in which a device for storing a hydrogenated compound or a halogenated compound gas and thereafter sending out the gas is 50 ° C. or higher. More preferably, 100
Most preferably, it is between 200C and 200C. If the temperature exceeds 200 ° C., a gaseous compound such as arsine is undesirably self-decomposed.

The time required for heating in the reaction accelerating step greatly depends on the heating temperature, but is preferably 1 hour or more, more preferably 5 hours or more, and most preferably the heating temperature of 100 ° C. or more. 8 hours or more.
If the heating time is short, the reaction is incomplete and the generation of impurity gas during actual storage cannot be prevented as expected, which is not preferable. Conditions in which heating requires several days are not preferable because the efficiency is extremely low in practice.

Further, the pressure in the closed space in the discharging step is controlled to be equal to or less than the atmospheric pressure, for example, arsine,
It is preferable to select the amount of gaseous compound such as phosphine and boron trifluoride and / or the heating temperature.

Further, a buffer space is provided in the closed space for smoothly discharging the impurity gas generated in the reaction promoting step and mixed in the gaseous compound such as arsine, phosphine and boron trifluoride in the discharging step. Is also good.

The discharging step of discharging the gas having passed through the reaction promoting step from the closed space is performed by reducing the pressure to about 10 to 5 mmHg with a vacuum pump while maintaining the temperature at 100 ° C. to 200 ° C. The treatment of the activated carbon with the gaseous compound may be performed before the cylinder is filled with the activated carbon for storing the gaseous compound, by treating a plurality of cylinders at once, or after each cylinder is filled with the activated carbon. . For example, from the complexity of taking out activated carbon treated with highly toxic arsine and distributing it to each cylinder, it is better to perform the gaseous compound treatment for each cylinder after distributing the activated carbon to each cylinder in advance.

The hydride or halogenated compound gas such as arsine, phosphine or boron trifluoride used in the pretreatment is not only physically adsorbed to the activated carbon adsorbent in the container, but also the hydrogen on the surface of the activated carbon adsorbent. , Nitrogen, oxygen,
Since it also causes chemisorption accompanied by a chemical reaction with carbon atoms, as a result, hydrogen, nitrogen, carbon monoxide and carbon dioxide are generated as impurities in the gas, and are mixed into the gas.

As an embodiment of this method, when it is desired to immediately use a hydrogenated compound or a halogenated compound gas such as arsine, phosphine or boron trifluoride, for example, arsine, phosphine or boron trifluoride is used. If heated at such a high temperature that the hydrogenated compound or the halogenated compound gas itself does not thermally decompose, the pretreatment can be completed efficiently in several hours, and for storage, for example, arsine,
A hydride gas such as phosphine or boron trifluoride or a halogenated compound gas is then adsorbed and transported to the use environment, for example, together with the cylinder. On the other hand, if there is sufficient time until the compound gas is used, a hydrogenation compound or a halogenated compound gas such as arsine, phosphine, boron trifluoride or the like used in the pretreatment is put into the apparatus and left to stand. What is necessary is just to replace it with a hydrogenated compound or a halogenated compound gas such as arsine, phosphine or boron trifluoride for storage. In addition, the required amount of a hydride compound such as arsine, phosphine, boron trifluoride or the like used in the pretreatment or a halogenated compound gas is sufficient to complete the reaction with the activated carbon completely. For example, there is no need to use hydride compounds such as arsine, phosphine and boron trifluoride or halogenated compound gases wastefully.

The amount of the hydride or halogenated compound gas such as arsine, phosphine, boron trifluoride or the like used in the pretreatment and / or the heating temperature is appropriately selected to reduce the pressure in the enclosed space to below atmospheric pressure. For example, it is possible to prevent leakage to the external environment at the time of discharging a hydride compound or a halogenated compound gas such as arsine, phosphine, boron trifluoride, etc. used in the pretreatment, so that impurities can be safely removed. It can be carried out.

As described above, in the present invention, an adsorption step of preliminarily contacting and adsorbing a hydrogenated compound and a halogenated compound gas in an enclosed space, a step of accelerating a system having undergone the adsorption reaction, and a step of accelerating the reaction When the activated carbon is treated by a series of discharge steps of discharging the gas having passed through the step from the enclosed space to absorb and store a hydrogen compound and a halogenated compound gas of the same type or different from the gas, the activated carbon is removed. The method or apparatus for preventing the purity of the stored gas from being reduced due to the impurity gas generated by the contact of the gas with the storage gas has been described in detail, but the content of the present invention is described in the claims. Various changes and modifications are possible within the scope.

For example, the filling amount of the activated carbon adsorbent may be appropriately selected in relation to the storage amount of arsine for storage. Further, the gas to be brought into contact in advance in the enclosed space and the storage gas do not necessarily need to be the same gas. For example, phosphine or boron trifluoride, which is used as an ion implantation gas in a semiconductor doping process along with arsine as a gas to be brought into contact in advance in a closed space, is used to forcibly remove impurities of the activated carbon adsorbent. After that, there is no problem if arsine is injected as a storage gas.

In the present invention, the structure of the apparatus proposed as a method and / or apparatus for storing and subsequently sending out a hydride or halogenated compound gas is provided with a heating unit, so that a specific hydrogen used for the production of an adsorbed semiconductor is provided. When desorbing and sending out at least a part of the fluorinated compound and the halogenated compound gas, the storage environment of the gas can be heated together with the activated carbon, by reducing the adsorption capacity of the activated carbon by heating, The purpose is to increase the amount of the gas that can be delivered under the same pressure, so that the effectively available amount of the stored gas can be increased.

The heating temperature for heating the storage environment of the gas together with the activated carbon when desorbing and sending at least a part of the gas is 30 ° C. or higher, which is a general use environment temperature in which the apparatus is used. Is preferably 40 ° C. or more, and most preferably 50 ° C. to 200 ° C. If the temperature exceeds 200 ° C., a gaseous compound such as arsine is undesirably self-decomposed.

When the heating is performed, an adsorption step according to the present invention in which the compound is brought into contact with a hydrogenated compound and a halogenated compound gas in advance in a closed space and adsorbed, and the system which has undergone the adsorption reaction is accelerated. It is preferable to use activated carbon that has been treated in a series of steps of a step and a discharge step of discharging the gas that has passed through the reaction promoting step from the closed space.

Hereinafter, an example of a method for producing activated carbon used in the present invention will be described in detail.

In general, phenol resins are roughly classified into resol resins, novolak resins and other special phenol resins and modified products. The phenol resin powder used for producing the activated carbon used in the present invention is not particularly limited. Although it is not something to do, for example,
No. 210, Japanese Patent Publication No. Sho 62-30212 and the like can be used as the granular or powdery special phenol resin. The outline of the production method is as follows.

At room temperature, 15 to 22% by weight of hydrochloric acid and 7-1
While stirring the mixed aqueous solution composed of 5% by weight of formaldehyde, phenol or a mixture composed of phenol and a nitrogen-containing compound such as urea, melamine, or aniline is added to the mixed aqueous solution at a ratio of 1/15 or less, Stirring is stopped and the mixture is allowed to stand before cloudiness is formed in the reaction system. During the standing, a pink granular phenol resin is formed and settles in the reaction system. Next, the whole reaction system is heated and heated to a temperature of 40 to 90 ° C. while stirring again to complete the reaction, washed with water, then neutralized with an aqueous ammonia solution, washed with water, dehydrated and dried. Most of the thus obtained granular phenolic resin is composed of primary particles having a particle size of 0.1 to 150 μm or secondary aggregates thereof.

This phenolic resin is a special phenolic resin powder having properties different from those of resole resins and novolak resins, and can be suitably used as a phenolic resin powder used for producing activated carbon used in the present invention. When the phenol resin is heated and refluxed in 500 ml of substantially anhydrous methanol, the following formula S = {(W ₀ −W ₁ ) / W ₀ } × 100, where W ₀ : the used resin W ₁ : Weight (g) of the resin remaining after heating and refluxing S: Methanol solubility (% by weight) of the resin can be used as an index indicating reactivity. That is, those having high methanol solubility have high reactivity. In the present invention, a phenol resin powder having a methanol solubility of usually 70% by weight or less, preferably 30% by weight or less, and most preferably 10% by weight or less is used.

The reason is that when the methanol solubility is 70% by weight or more, the heat fusibility is high, and in the heating process during carbonization, the communication gap between the phenolic resin particles is filled due to the heat fusion, This is because the continuity of the pores of the carbide is reduced and the adsorption capacity is reduced. In order to obtain activated carbon having a sufficient adsorption capacity, it is preferable to use a phenol resin powder having a methanol solubility in the above range.

As another method for producing a phenol resin powder used for producing the activated carbon used in the present invention, a phenol resin and an aldehyde are reacted at least in the presence of a nitrogen-containing compound to obtain a condensate. A method in which a hydrophilic polymer compound is added and reacted (Japanese Patent Publication No. 53-129)
No. 58), a method in which a prepolymer obtained by reacting phenol and formaldehyde in a basic aqueous solution is mixed with a protective colloid, and coagulated into inert solid beads under acidic conditions (Japanese Patent Publication No. 51-13491). There is. Other examples include JP-A-61-51019, JP-A-61-127719, and JP-A-61-25881.
No. 9, JP-A-62-272260, JP-A-62-272260
A phenol resin powder produced by a method described in, for example, JP-A-2-1748 can also be used.

The resole resin usually has a molar ratio of phenol to formaldehyde of 1: 1, in the presence of a basic catalyst such as, for example, sodium hydroxide, ammonia or an organic amine.
It is produced by reacting under an excess of formaldehyde such as 1-2. The resol resin thus obtained has a large amount of phenol having a relatively large amount of free methylol groups, and has high reactivity.

The novolak resin is usually reacted in the presence of an acid catalyst such as oxalic acid under a phenol-excess condition such that the molar ratio of phenol to formaldehyde is 1: 0.7 to 0.9. Manufactured by The novolak resin obtained by such a method is mainly composed of a trimer to pentamer in which phenol is bonded by a methylene group, and hardly contains a free methylol group,
Therefore, it does not have self-crosslinking property by itself but has thermoplasticity. Therefore, the novolak resin is added with a crosslinking agent which is itself a formaldehyde generator and an organic base catalyst generator, such as hexamethylenetetramine, or, for example, a solid acid catalyst and paraformaldehyde are mixed and heated. A cured product can be obtained by the reaction.

These resol resins, novolak resins and the like can be used as the raw material resin powder of the present invention by being cured once and then pulverized.

The particle diameter of the phenol resin powder used for producing the activated carbon used in the present invention is usually 0.1 to 150 μm.
m, preferably 0.5 to 50 μm, most preferably 1 to
30 μm.

The binder used for producing the activated carbon used in the present invention is not particularly limited, and examples thereof include a liquid thermosetting resin, polyvinyl alcohol (PVA), and creosote oil. It is preferably used.

Examples of the liquid thermosetting resin include a liquid resol resin, a liquid melamine resin, and modified resins thereof.

Here, the liquid resole resin is produced by reacting phenol with an excess of aldehyde in the presence of a basic catalyst as described above. The body is the main component.

The liquid melamine resin is a so-called thermosetting resin, and after a chemical reaction is promoted by heating, it undergoes a form of a hydrophilic initial polymer or a state of a slightly condensed hydrophobic condensate. It becomes an insoluble and infusible cured product.

The liquid melamine resin is produced by adding aldehyde, usually formaldehyde, to melamine.
Also, various alcohols may be used simultaneously. Melamine resin is formed by first adding formaldehyde to melamine as a methylol group, then dehydrating and condensing the methylol group with the amino group or imino group of another molecule to form a methylene group, or dehydration between methylol groups. The reaction proceeds by a reaction of condensing into a dimethylene ether bond or a reaction of dehydration and etherification between a methylol group and an alcohol.

The liquid melamine resin can be divided into a water-soluble resin and an oil-soluble resin, and the water-soluble resin is generally produced using methanol as an alcohol. On the other hand, the oil-soluble resin is also called a butylated melamine resin, and usually uses butanol as an alcohol. The liquid melamine resin used as a binder used for producing the activated carbon used in the present invention may be water-soluble or oil-soluble, and may be produced by a known method.

The polyvinyl alcohol used to produce the activated carbon used in the present invention preferably has a degree of polymerization of 1
It has a saponification degree of 70% or more and a degree of saponification of 70 to 5000, and those partially modified with a carboxyl group or the like are also preferably used.

In producing the activated carbon used in the present invention, a granular molded product is obtained by mixing the phenol resin powder and the binder component and then granulating the mixture. 5 to 90 parts by weight based on 100 parts by weight of phenol resin powder.

The content of the binder is preferably from 10 to
60 parts by weight, most preferably 20 to 40 parts by weight.
If the content of the binder is less than 5 parts by weight, the workability at the time of granulation is reduced and extrusion from a die becomes difficult, the shape of the granulated material is irregular, the strength is low, and powder is easily generated. Problems arise. Also, if it exceeds 90 parts by weight,
Again, the workability during granulation is reduced, and the continuity of the pores in the pellets after the carbonization is activated is reduced, and the performance as an adsorbent deteriorates, which is not preferable.

The mixing of the phenolic resin powder and the binder component is performed at room temperature or under heating by using a ribbon mixer,
What is necessary is just to perform with a commercially available mixing stirrer, such as a mold mixer, a cone mixer, and a kneader.

In the production of the activated carbon used in the present invention, the addition of other additional components in addition to the phenolic resin and the binder component is not limited at all, and examples thereof include starch and crystalline cellulose powder. , Methylcellulose, water, a solvent and the like can be added in appropriate amounts. Further, addition of a small amount of coke, coconut shell charcoal and the like is not limited at all.

Further, in producing the activated carbon used in the present invention, for example, ethylene glycol,
A small amount of a surfactant such as polyoxyethylene, alkyl ether, polyoxyethylene fatty acid ester, and ammonium polycarboxylate, a crosslinking agent for polyvinyl alcohol, and a plasticizer for extrusion granulation can be added.

In the production of the activated carbon used in the present invention, after being uniformly mixed by the mixing device as described above,
Then it is formed into granules. The shaping into granules can be performed by, for example, a single-screw or twin-screw wet extrusion granulator, a vertical granulator such as a basketluser, a semi-dry disc pelleter, or the like. This molding is usually performed at room temperature, but may be performed under heating depending on the case. The granulated material thus obtained is subjected to a drying treatment in a temperature range of usually about 50 to 400 ° C. to obtain a granular molded product.

The shape of the granular molded product is usually a columnar or spherical pellet, and is adjusted at the time of granulation so that the pellet shape after carbonization activation becomes a predetermined shape.

For producing the activated carbon used in the present invention,
The granular molded product obtained as described above, or the carbide obtained by heat-treating it at 500 to 900 ° C. in a non-oxidizing atmosphere,
The desired activated carbon is obtained by performing an activation treatment in a temperature range of 00 to 1100 ° C. so that the weight reduction rate based on the carbide is 5 to 40%.

In the production of the activated carbon used in the present invention, the carbonization of the granular molded product before the activation treatment is performed by an electric furnace,
The heat treatment is performed at 500 to 900 ° C. in a non-oxidizing atmosphere using a heat treatment apparatus such as an externally heated gas furnace. The non-oxidizing atmosphere in this case is, for example, an atmosphere of nitrogen, argon, helium, or the like.

The carbonization temperature is usually 500 to 900.
° C, preferably 550-850 ° C, most preferably 600-800 ° C. If the carbonization temperature is higher than 900 ° C., the activation rate in the next activation treatment step becomes slow, and the activation cannot be efficiently advanced, which is not preferable. When the carbonization temperature is 500 ° C. or lower, the temperature is too low, and carbonization does not progress very much, which is not preferable.

To produce the activated carbon used in the present invention,
The above-mentioned granular molded product, or the same under a non-oxidizing atmosphere of 500 to
The carbide heat treated at 900 ° C. is activated. The temperature range of the activation treatment is 700 to 1100 ° C, preferably 800 to
1000 ° C, most preferably 850-950 ° C.
If the temperature of the activation treatment is higher than 1100 ° C., the pore volume is decreased by heat shrinkage, or the surface of the activated carbon is oxidized, so that the abrasion resistance is undesirably reduced.
If the temperature is lower than 600 ° C., the activation is not performed sufficiently,
Adsorption capacity is low, which is not preferable.

In the production of activated carbon used in the present invention, the activation treatment includes oxygen, carbon dioxide, water vapor or a mixed gas of two or more of these, or nitrogen, argon, helium containing these gases. Atmosphere gas such as methane, propane, butane and the like, and the weight reduction rate based on carbide is 5%.
Activation is performed within a range of ４０40%.

If the weight reduction ratio is less than 5%, the development of the pores is insufficient, and the pore volume is too small, so that sufficient performance cannot be secured, which is not preferable. In addition, the weight loss rate is 40
%, The ratio of pores of 0.6 to 0.8 nm that effectively works for the adsorption of gaseous compounds such as arsine and phosphine decreases, and the particle bulk density decreases. When filled, the amount of effective adsorption sites per unit volume decreases, which is not preferable.

The activated carbon used in the present invention is filled in a container such as a cylinder at a gas manufacturing facility, and adsorbs gaseous compounds such as arsine, phosphine and boron trifluoride used for ion implantation gas in the semiconductor industry. And used to stably store these gaseous compounds until use. At a manufacturing site for semiconductors or the like, these gaseous compounds are taken out of the cylinder by drawing a negative pressure as necessary. Since the pressure inside the cylinder is kept below the atmospheric pressure, the danger of highly toxic arsine, phosphine, etc. leaking from the cylinder to the surrounding environment is extremely small.

The gaseous compounds to be adsorbed and stored by activated carbon used in the present invention include, for example, arsine, phosphine, boron trifluoride, boron trichloride, tungsten hexafluoride, silane, diborane, chlorine, B ₂ D ₆ , (CH ₃ )
₃ Sb, hydrogen fluoride, hydrogen chloride, hydrogen iodide, germane,
Ammonia, stibine, a gaseous compound selected from the group consisting of hydrogen sulfide, hydrogen selenide, hydrogen telluride and NF _3, arsine as the best compound adsorption storage,
Phosphine and boron trifluoride.

[0076]

First, the measurement and evaluation method used in the present invention will be described below.

(1) Method for measuring the amount of adsorbed arsine and the amount of released arsine A stainless steel test container having an inner diameter of 30 mm, a length of 150 mm, and a capacity of 100 ml having a diaphragm type shut-off valve at one end is weighed in advance by an analytical balance. The weight of the test container at this time is W0. After each of the adsorbents used for the test is filled in the test container, the test container is connected to a vacuum pump through a shutoff valve, and the test container is evacuated until the pressure in the test container becomes 0.01 mmHg or less. Further, the test container is gradually heated from the outside by a heating device until the inside of the test container reaches 350 ° C., and then the inside of the test container is evacuated by a vacuum pump to 0.01 mmHg or less. Thereafter, heat is released to return to room temperature, and the test container is weighed again. The weight of the test container at this time is defined as W1.

Next, the test container was heated at a constant temperature of 2 using a thermostat.
While maintaining the temperature at 0 ° C., the arsine is introduced into the test container through the shut-off valve while adjusting the pressure in the test container to 700 mmHg or less at atmospheric pressure until it is not absorbed any more. The weight of the test container at this time is W2.

The test container is connected to a gas chromatography mass spectrometer via a pressure gauge, a flow controller and a vacuum pump to perform quantitative analysis. The pressure gauge is installed to measure the internal pressure when the inside of the test vessel is evacuated by the vacuum pump, and the flow controller is installed to control the flow rate of the released arsine when flowing out of the test vessel. While controlling the flow rate of the released arsine to 1 ml / min to 10 ml / min, the inside of the test container is pulled by a vacuum pump to an internal pressure of 20 mmHg, and arsine is sent out from the test container to the outside. The test container is then weighed again. The weight of the test container at this time is defined as W3.

Further, the inside of the test container was pulled down to 0.01 mmHg by a vacuum pump, and then the inside of the test container was heated by a heating device and kept at 100 ° C. to 150 ° C. for about 4 hours.
Weigh the test container again. The weight of the test container at this time is defined as W4. The amount of released arsine is W2-W3, W
2-W4, the residual arsine amount was W3-W1, W4, respectively.
Determined by -W1.

(2) Method of Measuring Pressure Change After 20 Days Each of the adsorbents used for the test was charged into a stainless steel test container having an inner diameter of 30 mm, a length of 150 mm, and a capacity of 100 ml, each having a diaphragm shutoff valve at one end. The test container is connected to a vacuum pump via a shutoff valve, and the inside of the test container is evacuated to 0.01 mmHg or less. Further, the test container is gradually heated from the outside by a heating device until the inside of the test container reaches 350 ° C., and then the inside of the test container is evacuated by a vacuum pump to 0.01 mmHg or less. Thereafter, heat is released and the temperature is returned to room temperature.

Then, the test container was heated at a constant temperature of 2 using a thermostat.
While maintaining the temperature at 0 ° C., the arsine is introduced into the test container through the shut-off valve while adjusting the pressure in the test container to 700 mmHg or less at atmospheric pressure until it is not absorbed any more. The weight of the test container at this time is W0.

Next, the test container was heated to a constant temperature of 2 using a thermostat.
The weight after 20 days is measured while maintaining at 0 ° C. The weight of the test container at this time is defined as W1. Calculate W1-W0, confirm that there is no difference due to leakage, and read the internal pressure.

(3) Method of measuring the amount of adsorbed arsine under a plurality of pressures A stainless steel test container having an inner diameter of 30 mm, a length of 150 mm, and a capacity of 100 ml having a diaphragm type shut-off valve at one end is weighed in advance by an analytical balance. The weight of the test container at this time is W0.

Next, the test container is filled with the adsorbent used for the test, and the test container is connected to a vacuum pump through a shutoff valve, and the test container is evacuated until the pressure in the test container becomes 0.01 mmHg or less. Further, the test container is gradually heated from the outside by a heating device until the inside of the test container reaches 350 ° C., and then the inside of the test container is evacuated by a vacuum pump to 0.01 mmHg or less. Thereafter, heat is released to return to room temperature, and the test container is weighed again. The weight of the test container at this time is defined as W1.

Next, the test container was heated at a constant temperature of 2 using a thermostat.
While maintaining the temperature at 5 ° C., the arsine was passed through the shut-off valve through the test vessel to a pressure of 10, 20, 30, 50, 100, 2 below atmospheric pressure.
Each of 00, 300, 400, 500, 600, 700
The pressure is adjusted to mHg and introduced into the test vessel at each pressure until no more is absorbed. The weight of the test container at this time is defined as Wn. In addition, numbers from 2 to 11 are assigned to n of Wn in order from the low pressure. Thereafter, the amounts of the adsorbent and the adsorbed arsine are determined by W1-W0 and Wn-W1, respectively.

(4) Particle Tensile Strength Measurement Method The tensile strength of activated carbon particles was measured with a Kiya hardness meter.
The tensile strength evaluated by the strength measurement was calculated from the load value at the time of crushing of the particles, the particle diameter, and the particle length by the following formula. Tensile strength: σ [kg / cm ² ] = 2P / (πdl) P: load [kg], d: particle diameter [cm], l: particle length [cm]

(5) Method for measuring the specific surface area of activated carbon After about 0.1 g of the activated carbon to be measured is accurately weighed, it is placed in a dedicated cell of a high-precision fully automatic gas adsorption apparatus BELSORP28 (manufactured by Nippon Bell Co., Ltd.). To adsorb nitrogen using B. E. FIG. It was determined by the T method.

(6) Method for Measuring Pore Volume The pore volume of the adsorbent of the present invention was measured using a pore diameter of 0.01.
The range of 10 to 10 μm is measured by a mercury intrusion method using a porosimeter (Pore Sizer 9310, manufactured by Shimadzu Corporation).
The nitrogen adsorption measurement was carried out. Specifically, the pore diameter is 2 to 1
The pore volume in the range of 0 nm was obtained by DH analysis of the adsorption isotherm of nitrogen gas at 77 K, and the pore diameter was 2 nm.
The pore volume of nm or less was determined by analyzing the t-plot of the adsorption isotherm of nitrogen gas at 77K using the MP method.

(7) Measuring method of ash About 1 g of a sample dried at 105 ° C. for 2 hours was precisely weighed in a platinum crucible, ashed at 700 ° C. for 2 hours, and weighed again to determine the amount of ash.

Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the examples.

Example 1 Phenol resin powder (manufactured by Kanebo Co., Ltd., Bellpearl R8)
(00: average particle diameter: 20 μm) 100 parts by weight of a melamine resin aqueous solution (Sumitec Resin M-3, manufactured by Sumitomo Chemical Co., Ltd., solid content concentration: 80% by weight) as a binder, having a degree of polymerization of 1700 and a degree of saponification of 99%. A predetermined amount of polyvinyl alcohol (hereinafter abbreviated as PVA) and potato starch, a surfactant (Rhodol SP-L10, manufactured by Kao Corporation) and water as additives were weighed.

First, phenol resin powder and potato starch were dry-mixed in a kneader for 15 minutes. On the other hand, the polyvinyl alcohol was dissolved in warm water to form a 15% by weight aqueous solution, and the aqueous polyvinyl alcohol solution, melamine resin aqueous solution, surfactant and water were added to a kneader and mixed for another 15 minutes.

This mixed composition was subjected to a twin-screw extrusion granulator (Peretta Double EXDF-100, manufactured by Fuji Paudal Co., Ltd.).
), And pelletized compacts having an outer diameter of about 1.0 mm and different binder contents were granulated. Table 1 shows the composition ratio of each raw material component.

[0095]

[Table 1]

[0096] The sample obtained in this way has an inner diameter of 70 mm.
Using a φ cylindrical electric furnace, under nitrogen atmosphere, heating rate 50
The temperature was raised to 650 ° C./° C./H and maintained for 1 hour to carbonize. Next, 20 g of the carbide was activated with steam under different conditions to obtain seven samples. That is, sample 1 is 750
C, 1.5 hours, Sample 2 was 900C, 1.5 hours, Sample 3 was 950C, 1.5 hours, Sample 4 was 980C, 1.5 hours.
Time, sample 5 is 1000 ° C., 1.5 hours, sample 6 is 10
00 ° C, 2.0 hours, Sample 7 is 700 ° C, 1.5 hours,
Nitrogen gas containing water vapor (activation gas composition molar ratio: N ₂ /
The activation treatment was performed using H ₂ O = 1/1 and a flow rate of 1.0 NL / min). Table 2 shows the activation conditions and characteristic values of the obtained carbonization activated product.

[0097]

[Table 2]

Table 3 shows the adsorption and release of arsine on these activated carbons.

[0099]

[Table 3]

In Samples 1 to 4, all the characteristic values were within the range specified by the activated carbon used in the present invention, and both the amount of adsorbed arsine and the amount of released arsine were high.

On the other hand, Samples 5 to 7 have any one of specific surface area, pore volume of 10 nm or less, ratio of pore volume of 0.6 to 0.8 nm or less, tensile strength, particle bulk density, packing density, etc. The above does not fall within the range specified by the present invention, and both the amount of absorbed arsine and the amount of released arsine are reduced.

Table 3 also shows changes in the internal pressure when arsine was adsorbed and stored using Sample 1, Sample 2, and general coconut shell activated carbon for gas adsorption (general activated carbon). As a result, when the activated carbon for general use is used, the amount of ash increases and the internal pressure increases. However, in the case of the samples 1 and 2 which are within the range of the activated carbon used in the present invention, the ash is The amount was small and no increase in internal pressure was observed.

Example 2 In Example 2, arsine or phosphine (hereinafter referred to as “preliminary”) was brought into contact with the sample 2 prepared in Example 1 in an enclosed space without performing pretreatment or at various heating temperatures. Pretreatment with arsine or phosphine), after which arsine (phosphine) for storage is injected into the test vessel,
A comparative experiment was performed to measure the change in pressure in the test vessel over time and the change in purity of stored arsine (phosphine).

FIG. 2 shows an outline of the experimental apparatus. The experimental apparatus is composed of a gas injection system, a gas exhaust system, a gas analysis system, and a test container system, and each system is a normally closed shutoff valve V1 to V1.
They are connected by pipes provided with V10. The gas injection system is independently connected to the test vessel system from shutoff valves V1 to V3 from arsine, phosphine, and helium gas sources R1 to R3, respectively. The gas discharge system is composed of a vacuum pump P1 and a molecular turbo pump P from the test container system.
2 to S1 so that the highly toxic arsine and phosphine can be safely discharged outside. The gas analysis system includes a normal gas analyzer A1, a pressure gauge G1, a Pirani vacuum gauge G2, and an ionization vacuum gauge G based on gas chromatography.
3 (the former is of the order of 10 ^-1 mmHg, the latter is of the order of 10 ^-5 mmHg)
mmHg order) and are connected to the respective test vessels via gate valves V6 to V10.

The test container system includes four test containers C1 each having an inlet / outlet shutoff valve CV1 to CV4 at the entrance / exit portion.
To C4, each having an electric heater unit for heating the inside of the test container from the outside of the test container, and each electric heater unit has a temperature control unit using thermocouple sensors T1 to T4. Each test container is filled with sample 2 as an adsorbent. At this time, the filling amount is such that a buffer space can be provided in the closed space above the entrance side of each test container.

(1) Initial vacuum treatment step In order to clarify that impurities are generated by the reaction of arsine or phosphine with the adsorbent, oxygen, nitrogen,
An initial vacuum processing step was performed to remove moisture and the like. First, the inlet / outlet gate valves CV1 to CV4 and the gate valve V4 are opened, and the inside of each test container is set to a vacuum of 0. 0 by the vacuum pump P1.
After the air is discharged from the test container to 1 mmHg, the gate valve V4 is closed.

Next, the gate valve V1 is opened, and helium, which is an inert gas, is injected from the gas source R3 to approximately atmospheric pressure into each of the test containers. Then, the gate valve V1 is closed, and then the gate valve V4 is opened again. Each test container is evacuated to a degree of vacuum of about 0.1 mmHg. Since this helium has the effect of promoting the replacement of air in the test container, the injection of helium may be repeated several times as appropriate. In addition, after opening the gate valve V1 and injecting helium, helium gas is introduced into the analyzer A1 through the gate valve V6 for analysis, and there is no generation of oxygen, nitrogen, carbon monoxide and carbon dioxide as impurities. You may check. By the way, helium is adsorbed on the sample 2 by helium injection, but it has been confirmed that such adsorption does not generate impurities.

Next, while each test container was heated to a predetermined temperature of 300 ° C. to 350 ° C. by an electric heater unit, the vacuum was continuously maintained, and when the degree of vacuum reached about 0.1 mmHg, the gate valve V4 was closed. V5 is opened, and high-vacuum processing is performed to a degree of vacuum of 10 ⁻⁵ mmHg or less by a molecular turbo pump P2. Finally, the inlet / outlet gate valves CV1 to CV4 and the gate valve V5 are closed to end the initial vacuum processing step. After radiating the heat of each test container to room temperature, the weight W of each test container
Weigh 0.

(2) Step of Injecting Preliminary Arsine (Arsine) Each test container C1 to C4 was kept at 20 ° C.
~ Open CV4 and gate valve V2 or V3,
With the gate valve V7 opened and using the pressure gauge G1, preliminary arsine or preliminary phosphine is injected into each test container until the pressure in each test container becomes approximately 20 mmHg. At this time, using a temperature control unit, the temperature inside the test container was set to 50 ° C. and 10 ° C. in the order of test containers C1 to C4.
Heat and maintain at 0 ° C., 150 ° C., and 200 ° C. respectively.

In order to measure impurities and pressure generated in each test container, each test container is appropriately connected to an analyzer A1 or a pressure gauge G1. Next, while maintaining the preliminary arsine (phosphine) temperature at 200 ° C. in all of the test containers C1 to C4, the vacuum pump P1 and the molecular turbo pump P2 were used to pull the vacuum to 10 ⁻⁵ mmHg, and the preliminary arsine (phosphine) containing impurities was mixed. ) Since the liquid can accumulate in the buffer space provided at the upper part, the discharge is performed smoothly.
After each test container is radiated to room temperature, the weight W1 of each test container is weighed.

(3) Step of adsorbing arsine (phosphine) for storage The test vessels C1 to C4 are each kept at 20 ° C., and the gate valves CV1 to CV4 and the gate valve V2 or V3 are opened. Using the total G1, until the pressure in each test container becomes approximately 400 mmHg, storage arsium or phosphine is injected into each of the test containers C1 to C4, and adsorbed on the sample 2 in the test container. next,
After confirming that no impurities are generated in each test container by the analyzer A1, the inlet / outlet gate valves CV1 to CV4 are closed, the weight W2 of each test container is weighed, and the gas weight W2-W1 in each test container is weighed. Is calculated.

(4) Experimental Results FIGS. 3 to 5 show the experimental results when arsine was used as the ion-implanted gas, and FIG. 6 shows the experimental results when phosphine was used.

FIG. 3 relates to the above (2) preliminary arsine (phosphine) injection step and shows a test container of the experimental apparatus of FIG. 2 when pretreated using the method according to the present invention at various heating temperatures. 6 is a graph showing the passage of time of the pressure in the inside.

As is clear from FIG. 3, the heating temperature is 50 ° C.
And 100 ° C., the pressure in the vessel gradually increased, and after 48 hours from the start of the heat treatment, each was about 33 mmH
g and 93 mmHg. It is expected that the pressure will gradually increase over time. On the other hand, when the heating temperature is 150 ° C. and 200 ° C., the pressure in the container rises sharply from the start of the treatment, and at 150 ° C., approximately 14 hours after the start of the treatment, and at 200 ° C., approximately 8 hours after the start of the treatment. , The pressure rise almost stops, and the pressure is 480
mmHg and 740 mmHg. From this,
The generation of impurity gas in the test vessel was about 8 at 200 ° C.
Time, about 14 hours at 150 ° C, 50 ° C and 1 hour
At 00 ° C., it is estimated that it is still continuing after 48 hours.

FIG. 4 is a bar graph showing the weight increase (W1-W0) of the weight W1 of the test container containing activated carbon after 48 hours in FIG. 3 with respect to the initial weight W0 of the test container containing the activated carbon adsorbent. This increment is due to the substitution reaction of the preliminary arsine with the impurity atoms consisting of oxygen, nitrogen and hydrogen bonded to the pore surface of sample 2 and the irreversible binding of arsine to the pore surface by chemical adsorption. Is estimated to have increased. In the case of heat treatment at 50 ° C. and 100 ° C., the increment of the latter is about 50% greater than that of the former, but at 150 ° C. and 200 ° C., the increment is almost the same, About three times, a considerable increase is seen. From this, it is presumed that when heat treatment was performed at 150 ° C. and 200 ° C., almost all of the primitive impurities on the pore surface reacted with the preliminary arsine and were replaced with arsine.

FIG. 5 relates to the above (3) adsorption step of arsine for storage (phosphine). After pretreatment of the method according to the present invention at various heating temperatures, arsine for storage was placed in a test container. It is a graph which shows the purity change of arsine for storage at the time of injection. Arsine for storage, temperature 2
After injection at 0 ° C. and a pressure of 400 mmHg, the mixture was allowed to stand at 35 ° C. In addition, the purity of arsine was calculated by obtaining the sum of the impurity concentrations of hydrogen, oxygen, nitrogen, methane, carbon monoxide and carbon dioxide.

As is clear from FIG. 5, when no pretreatment was performed and when heating was performed at 50 ° C. and 100 ° C., respectively, about 2 weeks, about 4 weeks, and about 7 weeks, respectively, The required purity falls below 99.9% in a week. On the other hand, in the case of 150 ° C. and 200 ° C., such a decrease in purity does not occur at this rate, and when estimated from the degree of progress of the purity decrease, it is not possible to fall below 99.9% until one year after injection. Not expected. Therefore, FIG. 5 demonstrates that pre-treatment of activated carbon by heating pre-arsine at at least 150 ° C. can be preserved or stored for a long time without introducing impurities into stored arsine. is there.

FIG. 6 is a diagram similar to FIG. 5 in the case of using phosphine. Although the purity reduction rate is slower than in the case of arsine, similar to arsine, in order to preserve or store for a long period of time, spare phosphine must be prepared. It indicates that it is necessary to heat to 150 ° C to 200 ° C.

Example 3 In Example 3, Table 4 shows the results of measuring the adsorbed amount of arsine under various pressures using the sample 2 produced in Example 1 and a general coconut shell activated carbon for gas adsorption. .

[0120]

[Table 4]

As shown in Table 4, Sample 2, which was within the range of activated carbon used in the present invention, showed very good results as compared with ordinary coconut shell activated carbon for gas adsorption.

Example 4 Using the gas storage device shown in FIG. 1, the weight of the device was measured according to the method described in the method for measuring the amount of adsorbed arsine and the amount of released arsine, and W1 was measured. 20 ° C, 70
Arsine gas was charged under the condition of 0 mmHg, and the weight was measured to be W2. According to the same method, the pressure was gradually reduced to 20 mmHg, and when the weight became stable, the weight was measured and the value was W3. Thereafter, heating is performed at 35 ° C. and 50 ° C.
The weight was similarly measured at temperatures of ° C, 100 ° C, and 150 ° C, respectively, and was determined to be Wn (n is 4, 5, 6, 7 in order, respectively). Table 5 shows the results.

[0123]

[Table 5]

As is evident from Table 5, by heating to an appropriate temperature, the amount of arsine obtained can be greatly increased, and it becomes possible to efficiently use the stored arsine.

Example 5 Using the gas storage device shown in FIG. 1, the weight of the device was measured according to the method described in the method for measuring the amount of adsorbed phosphine and the amount of released phosphine, and W1 was measured. And 20 ° C,
Phosphine gas was charged under the condition of 700 mmHg, and the weight was measured. 20 mm according to the same method
The pressure was gradually reduced to Hg, and when the weight became stable, the weight was measured to be W3. After that, heating is performed and 35
C., 50 ° C., 100 ° C., and 150 ° C., and the weight was measured in the same manner, and Wn (n is 4, 5,
6, 7). Table 6 shows the results.

[0126]

[Table 6]

As is evident from Table 6, by heating to an appropriate temperature, the amount of phosphine obtained can be greatly increased, and it becomes possible to use stored phosphine efficiently.

[0128]

As described above in detail, according to the present invention, gas compounds such as arsine, phosphine, boron trifluoride and the like which are adsorbed on activated carbon at a pressure lower than the atmospheric pressure and which are used for ion implantation gas in the semiconductor industry, for example, , Easily detached by differential pressure. At this time, it is possible to prevent a problem that has occurred in the related art, that is, a situation in which a storage environment at a pressure lower than the atmospheric pressure becomes higher than the atmospheric pressure due to self-decomposition during storage. Therefore, when a gas compound such as arsine, phosphine, and boron trifluoride used as a necessary amount of ion-implanted gas for a semiconductor manufacturing apparatus is sent out in another working environment, if the pressure is reduced to a negative pressure, the ambient environment at atmospheric pressure is reduced. High-purity gaseous compounds without leaking highly toxic gases.

Further, by increasing the desorption temperature of the gaseous compound such as arsine, phosphine and boron trifluoride, which is adsorbed, to increase the desorption amount of the gas, the pressure in the storage environment is maintained below the atmospheric pressure. As it is, it has become possible to increase the rate of taking out the gas.

Further, for example, an adsorption step of preliminarily contacting and adsorbing a hydride compound and a halogenated compound gas used in semiconductor production in a closed space, a step of accelerating the system after the adsorption reaction, and a step of accelerating the reaction By using activated carbon, which has been subjected to a series of steps of a discharging step of discharging the gas having passed through the closed space from the enclosed space, the storage gas caused by the impurity gas generated by the contact between the activated carbon and the stored gas during gas storage is used. Purity reduction was prevented, and gas compounds such as arsine, phosphine, and boron trifluoride with extremely high purity could be supplied.

After filling a 100 ml stainless steel test container with activated carbon optimal for the method or apparatus of the present invention,
Connect to a vacuum pump, evacuate the inside of the test container to 0.01 mmHg or less, gradually heat the test container from the outside until the inside of the test container reaches 350 ° C. with a heating device, and then continuously use the vacuum pump to test the test container. After evacuating the inside to 0.01 mmHg or less, radiating heat and returning to normal temperature,
Next, while maintaining the test container at a constant temperature of 20 ° C. by using a thermostat, for example, arsine was introduced into the test container at a pressure of 70 ° C. or less under atmospheric pressure.
0 It is possible to adsorb 36 g or more of arsine when introduced into a test container while adjusting the pressure to each mmHg until it is not absorbed any more, and it is possible to adsorb arsine very efficiently compared to conventional activated carbon. It can be suitably used as a cylinder for storing gaseous compounds and for efficiently desorbing these gaseous compounds at the use site of the gaseous compounds.

When the most suitable activated carbon is used in the method or the apparatus of the present invention, for example, as described above, after adsorbing arsine,
When stored at 0 ° C for 20 days without gas leakage from the cylinder, the internal pressure shows almost 100% even after 20 days when the initial pressure is set to 100%, compared to the conventional activated carbon. Since arsine can be stored very stably, the gaseous compound can be stored and can be suitably used as a cylinder for efficiently desorbing the gaseous compound at the use site of the gaseous compound.

When the most suitable activated carbon is used in the method or apparatus of the present invention, for example, as described above, after adsorbing 100.0% of arsine, keeping the temperature at 20 ° C., there is no gas leakage from the cylinder. After storing for 30 days at, the purity of arsine was determined to be 99.9% or higher,
Since arsine can be stored much more stably than conventional activated carbon, it can store gaseous compounds and can be suitably used as a cylinder for efficiently desorbing these gaseous compounds at the use site of the gaseous compounds.

[Brief description of the drawings]

FIG. 1 is a device for storing a hydrogenated compound or a halogenated compound gas in the present invention and for sending out the gas thereafter.

FIG. 2 is an example of the device of the present invention.

FIG. 3 shows the time course of the pressure in the test vessel of the experimental apparatus of FIG. 2 when pretreatment using the method according to the present invention at various heating temperatures using arsine as the ion implantation gas of the present invention. It is a graph shown.

4 is a bar graph showing the weight increase of the test container containing the activated carbon adsorbent after 48 hours in FIG. 3 with respect to the initial weight of the test container containing the activated carbon adsorbent.

FIG. 5 is a graph showing a change in purity of storage arsine when storage arsine is injected into a test container after pretreatment at various heating temperatures in accordance with the contents described in the present invention.

FIG. 6 is a graph showing a change in purity of the storage phosphine when the storage phosphine is injected into the test container after performing the pretreatment according to the contents described in the present invention at various heating temperatures.

[Explanation of symbols]

 Reference Signs List 1 container 2 container valve 3 container valve built-in filter 4 upper space 5 purge valve 6 pressure gauge 7 bypass valve 8 line filter 9 air drive valve 10 mass flow controller 11 connection pipe 12 activated carbon

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI C01B 35/06 C01B 35/06 H01L 21/265 H01L 21/205 // H01L 21/205 21/265 (72) Inventor Koji Ishimori 1557 Tsuruma, Machida-shi, Tokyo Inside Takachiho Chemical Industry Co., Ltd. (72) Inventor Satoshi Ibaraki 2-18-55-305 Yuginagi 2-chome, Minato-ku, Osaka-shi, Osaka 1-5-10-306 (56) References JP-A-9-110409 (JP, A) JP-A-47-27181 (JP, A) WO 96/11739 (WO, A1) (58) Fields investigated (Int.Cl. ⁷ , DB name) F17C 11/00 C01B 6/06 C01B 6/34 C01B 31/00-31/10 C01B 25/08 C01B 35/06

Claims (13)

(57) [Claims] 1. A step of contacting a predetermined amount of a gas of a hydrogenated compound or a halogenated compound with activated carbon, adsorbing the gas on activated carbon under a storage environment at a pressure lower than atmospheric pressure, and storing the gas. Desorbing and adsorbing at least a portion of the gas from the activated carbon and sending it to the working environment, wherein the activated carbon is a carbonized phenol resin powder, activated particles. Is a granular carbon molded product having a specific surface area of 70
0 to 1500 m ² / g, pore volume of 0.01 to 10 μm, pore volume of 0.1 to 1.0 cc / g, pore diameter of 10 nm
The following pore volume is 0.20 to 0.80 cc / g,
The ratio of the pore volume of the pore diameter of 0.6 to 0.8 nm to the pore volume of the pore diameter of 10 nm or less is 75 vol% or more, the particle bulk density is 0.4 to 1.1 g / cc, and the packing density is 0.30 to 0.70 g / cc, ash content is 1.0% or less,
Activated carbon having a tensile strength of activated carbon particles of 30 kg / cm ² or more, wherein the activated carbon is stored and sent out.
Hydride or halogenated compound gas in a closed space
An adsorption step of pre-contacting and adsorbing
A reaction promoting step of reacting the gas with activated carbon
The impurity gas generated by the reaction promotion process
A method of storing and delivering gas using activated carbon that has been processed through a discharging step of discharging from a gas. 2. A method for storing and sending gas according to claim 1.
In the above-described reaction promoting step in the method,
Gas storage / delivery method characterized by heating the space
Law. 3. The storage and storage of a gas according to claim 1 or 2.
In the delivery method, in the above-mentioned reaction promoting step,
Supplied in a closed space so that the pressure in the space is below atmospheric pressure
Adjust the supply amount of the above gas and the temperature in the enclosed space.
A method for storing and delivering gas. 4. The air according to claim 1, wherein
In the body storage / delivery method,
Inside the enclosed space so that the pressure inside the enclosed space is below atmospheric pressure
The supply amount of the above gas and the temperature in the enclosed space
A gas storage / delivery method characterized by adjusting. 5. The air according to claim 1, wherein
In the body storage / delivery method , buff
Gas storage / delivery method characterized by the provision of a space
Law. 6. The air according to any one of claims 1 to 5,
In the method of storing and delivering the body,
Release at least a part of the gas from the working environment
Characterized by heating the storage environment during the step of causing
Gas storage / delivery method. 7. The air according to any one of claims 1 to 6,
In the method for storing and delivering a body, the above hydrogenated compound or
The gas of the halogenated compound is arsine, phosphine, 3
It is a gas selected from boron fluoride
How to store and deliver gas. 8. A step of contacting a predetermined amount of a gas of a hydrogenated compound or a halogenated compound with activated carbon, adsorbing the gas on activated carbon in a storage environment at a pressure lower than atmospheric pressure, and storing the gas; A step of desorbing at least a part of the adsorbed gas from the activated carbon and sending it to the working environment, wherein the activated carbon is carbonized phenol resin powder, activated particles. Is a granular carbon molded product obtained by bonding
~1500m ² / g, pore volume of pores having a pore diameter 0.01~10μm is 0.1~1.0cc / g, volume of pores pore diameter 10nm is located in 0.20~0.80cc / g And the ratio of the pore volume of the pore diameter of 0.6 to 0.8 nm to the pore volume of the pore diameter of 10 nm or less is 75 vol% or more, the particle bulk density is 0.4 to 1.1 g / cc, and the packing density is Is 0.30 to 0.70 g / cc, the ash content is 1.0% or less,
Activated carbon having a tensile strength of activated carbon particles of 30 kg / cm ² or more, wherein the activated carbon is stored and sent out.
Hydride or halogenated compound gas in a closed space
An adsorption step of pre-contacting and adsorbing
A reaction promoting step of reacting the gas with activated carbon
The impurity gas generated by the reaction promotion process
A gas storage / delivery device characterized by using activated carbon that has been processed through a discharge step of discharging from a gas. 9. A gas storage and delivery device according to claim 8.
At least the above gas adsorbed on activated carbon
During the process of removing some of them and sending them out to the working environment,
Gas storage and delivery characterized by heating the storage environment
apparatus. 10. A gas storage according to claim 8 or 10.
Storage and delivery equipment,
In a closed space so that the pressure in the closed space is less than atmospheric pressure
Adjust the supply amount of the above gas and the temperature in the enclosed space.
A gas storage / delivery device characterized in that it is regulated. 11. The method according to claim 8, wherein
Gas storage and delivery methods,
Closed air so that the pressure in the closed space
The supply amount of the above gas to be supplied into the space and the temperature in the closed space
A gas storage / delivery method characterized by adjusting the degree. 12. The method according to claim 8, wherein
In the method of storing and delivering gas,
Storage and delivery of gas characterized by having a buffer space
Method. 13. The method according to claim 8, wherein
Hydrogen storage compound
Or the halogenated compound gas is arsine, phosphine
Is a gas selected from boron trifluoride.
A gas storage and delivery device.