JPH06269631A - Removal of gaseous silicon compound, and removing agent and its prep aration - Google Patents

Abstract

PURPOSE:To improve the repeatability of a removal capability of a gaseous silicon compound using aluminum oxide to a maximum possible extent by allowing vapor to come in contact with aluminum oxide under specific temperature conditions, and then gas containing a gaseous silicon compound to come in contact with the aluminum oxide. CONSTITUTION:Aluminum oxide which is in a state that a physically adsorbed water is not present, is allowed to come in contact with vapor under 100 to 200 deg.C temperature conditions. Then the aluminum oxide is activated, and the capability of removing the gaseous silicon compound is maximized. Consequently, if gas containing the gaseous silicon compound is allowed to come in contact with the activated aluminum oxide, the silicon oxide in the gas is adsorbed onto the surface of the aluminum oxide and removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing a gaseous silicon compound, a removing agent and a method for producing the same, and more particularly to removal of a gaseous silicon compound such as silane.

[0002]

2. Description of the Related Art For example, exhaust gas discharged from a semiconductor manufacturing process contains a gaseous silicon compound such as silane as a harmful component. Therefore, it is necessary to remove the gaseous silicon compound in the exhaust gas and then release the exhaust gas to the atmosphere.

As a method of removing a gaseous silicon compound, for example, Japanese Patent Publication No. 4-19886 proposes contacting an exhaust gas containing the gaseous silicon compound with aluminum oxide (Al ₂ O ₃ ).

[0004]

However, when the present inventors tested using commercially available aluminum oxide, it was found that some of the same aluminum oxides could not remove silane. In addition, even if silane can be removed, each manufacturer has different removal processing capacities. Even if it is the same manufacturer, it has different removal processing capacities. Even if aluminum oxide stored in the same container is used immediately after purchase. It was found that there was a difference in the removal treatment capacity between the case of doing and the case of using the rest after several days. That is, the difference in the manufacturing method of aluminum oxide by each manufacturer, the difference in the process of filling the manufactured aluminum oxide into a container, the change of aluminum oxide until it is sold after manufacturing, It was found that the removal treatment capacity of aluminum oxide for silane differs depending on the history of storage conditions and the like.

As described above, in the removal of gaseous silicon compounds using aluminum oxide, since the removal treatment capacity varies depending on the history of aluminum oxide used, uniform performance is obtained when it is used by incorporating it into the process. However, the inconvenience that the stability is poor occurs.

Therefore, an object of the present invention is to provide a means capable of improving the removal ability of gaseous silicon compounds by aluminum oxide with good reproducibility and maximally.

[0007]

In order to achieve the above object, the method for removing a gaseous silicon compound according to the present invention uses aluminum oxide from which physically adsorbed water has been removed, if necessary.
It is characterized in that water vapor is brought into contact under a temperature condition of 0 to 200 ° C. and then a gas containing a gaseous silicon compound is brought into contact therewith.

The gaseous silicon compound removing agent of the present invention is characterized in that it is obtained by contacting aluminum oxide, from which physically adsorbed water has been removed, if necessary, with steam under a temperature condition of 100 to 200 ° C. Further, the method for producing a gaseous silicon compound removing agent of the present invention is characterized in that aluminum oxide from which physically adsorbed water is removed as necessary is brought into contact with water vapor under a temperature condition of 100 to 200 ° C. There is.

[0009]

[Operation] When aluminum oxide in the absence of physically adsorbed water is brought into contact with water vapor under a temperature condition of 100 to 200 ° C, aluminum oxide is activated and the removal treatment capacity for gaseous silicon compounds is maximized. . Therefore, when a gas containing a gaseous silicon compound is brought into contact with the activated aluminum oxide, the gaseous silicon compound in the gas is adsorbed on the surface of the activated aluminum oxide and removed.

The gaseous silicon compound adsorbed on the surface of aluminum oxide does not separate due to the subsequent temperature change and pressure change. Therefore, although the aluminum oxide adsorbing the gaseous silicon compound cannot be regenerated, it is once removed. The generated gaseous silicon compound is surely removed.

The gaseous silicon compounds which can be removed according to the present invention include silanes such as monosilane, disilane and trisilane, that is, hydrides of silicon and halides of silicon such as diclocurlan and trichlorosilane, and aluminum oxide. Includes all removable substances.

[0012]

Example As described above, when aluminum oxide in the absence of physically adsorbed water is contacted with water vapor at a predetermined temperature, aluminum oxide is activated, which is obtained as a result of various studies by the inventors. It is the knowledge. This will be described in detail below based on examples.

First, five types of commercially available aluminum oxide (stored in a bottle) were obtained, and the ability to remove silane was tested as it was. All of the five types of aluminum oxide obtained have a crystal structure of γ-alumina and are usually called activated alumina.

FIG. 1 shows a flow sheet of the test apparatus, which has an inner diameter 43 having a gas inlet pipe 1 and a gas outlet pipe 2.
A filling cylinder 3 made of a stainless steel tube having a length of 600 mm and a length of 600 mm is provided with heating means 4 for controlling the inside of the cylinder to a predetermined temperature, and the gas introduction pipe 1 is provided with monosilane in nitrogen gas through a valve 5. A sample gas filling container 6 filled with a sample gas containing 1%, a pure water tank 8 equipped with a valve 7, and the pure water tank 8
Bypass path 10 having a bypass valve 9 for bypassing
The purge gas filling container 11 filled with nitrogen gas having high dryness is connected via the. Further, the gas outlet pipe 2 is provided with an analyzer 12 which is a tape-type hydride detector (AD-10 analyzer manufactured by Nippon Oxygen), and the filling cylinder 3 is provided with a thermometer 13 and the detection of the thermometer 13. The heating means 4 depending on the value
And a temperature control means 14 for controlling the temperature.

Then, the above-mentioned commercially available activated alumina was filled in the filling cylinder 3 so as to have a filling height of 300 mm, and then a sample gas was caused to flow to measure the monosilane removal ability of each activated alumina. The flow rate of the sample gas is
The volume was 1 liter / minute, and the same amount was used in the following tests. Further, when the monosilane concentration in the analyzer 12 provided in the gas outlet pipe 2 became 5 ppm, the usage limit of the remover was set, and the removal treatment amount was calculated from the time when the usage limit was reached and the flow rate of the sample gas.

The results are shown in Table 1. In the table, A,
B, C, D, and E represent the above-mentioned commercially available five types of activated alumina, and are arranged in the order of the removal treatment amount for monosilane. Further, in Table 1, A and C are the same activated alumina (Neobead GB manufactured by Mizusawa Chemical Co., Ltd.), A is the one in which the lid of the bottle has been opened for 10 days to obtain water, and C is the same. It was stored in a dry state after it was obtained. Also,
Samples B, D, and E were tested after being stored in a dry state after being obtained.

[0017]

[Table 1]

It can be seen from Table 1 that the amount of monosilane removal treatment for each activated alumina varies depending on the history.

Next, the activated alumina of the above A was used, and this was simply dried and subjected to the same test. In particular,
The heating means 4 of the filling cylinder 3 is operated, and the activated alumina in the filling cylinder 3 is filled with 30 ° C., 80 ° C., 110 ° C., 200 ° C., 30 ° C.
In the state of 0 ° C., the dry gas is brought into contact with the dry nitrogen gas passing through the bypass path 10 from the purge gas filling container 11 for 1 hour each to perform the drying treatment, and the filling cylinder 3 is naturally cooled to 25 ° C., and then the sample gas is flowed to perform the test. I went. The activated alumina in the filling cylinder 3 was replaced after each test. The same applies to the following tests. The results are shown in Table 2.

[0020]

[Table 2]

As is clear from Table 2, in the case of no treatment, the amount of monosilane removed was similar to the above, but the contact temperature between activated alumina and nitrogen gas was 30 ° C.
The removal treatment amount increased as the temperature increased to 80 ° C and 110 ° C. This is probably because the physically adsorbed water adhering to the surface of the activated alumina was removed by drying. From this, in the case of untreated activated alumina,
It is probable that the physically adsorbed water that had adhered to the surface of the aluminum oxide in a large amount had a detrimental effect on the removal of monosilane, and eventually the monosilane could not be removed at all.

As described above, the monosilane removal treatment amount increases as the dryness of activated alumina increases,
If the contact temperature between the activated alumina and the nitrogen gas exceeds 200 ° C., the monosilane removal treatment amount decreases rather. From this, the physically adsorbed water adhering to the surface of the activated alumina is harmful to the removal of monosilane, but the amount of monosilane removal treatment cannot be increased simply by reducing the amount of physically adsorbed water.

In order to confirm the above facts, the contact temperature between activated alumina and nitrogen gas was set to 200 ° C., and the contact time was
The amount of monosilane removal treatment was tested at 1 hour, 5 hours, 16 hours, and 48 hours, respectively. The results are shown in Table 3.

[0024]

[Table 3]

As is clear from Table 3, when the dryness of the activated alumina becomes higher than a certain limit, the monosilane removal treatment amount decreases.

Next, the activated alumina in the packing cylinder 3 is dried to remove the physically adsorbed water, and then the dried activated alumina is added to 80 ° C., 110 ° C., 200 ° C., 250 ° C., 300 ° C.
The test was conducted by contacting with steam at a temperature of ° C.

Specifically, the inside of the filling cylinder 3 is maintained at 200 ° C., dry nitrogen gas is contacted with the activated alumina for 10 hours to sufficiently dry the activated alumina, and then the filling cylinder 3 is flowed while flowing the nitrogen gas. After the temperature was adjusted to the predetermined temperature, nitrogen gas was bubbled in the deionized water tank 8 to introduce water vapor into the filling cylinder 3. Therefore, the water vapor comes into contact with the activated alumina at each of the above temperatures from the beginning. After contacting activated alumina and water vapor at each temperature for 1 hour, the inside of the filling cylinder 3 was naturally cooled to 25 ° C., and then a sample gas was flowed to perform the test. The results are shown in Table 4.

[0028]

[Table 4]

As is clear from Table 4, the monosilane cannot be removed by contacting the dried activated alumina with water vapor at a temperature of 80 ° C. This is probably because the physically adsorbed water adhered to the surface of the activated alumina as described above. However, 11
When steam is contacted at temperatures of 0 ° C. and 200 ° C., the ability to remove monosilane sharply increases. This is probably because the chemisorbed water adhered to the surface of the activated alumina. However,
When the contact temperature between activated alumina and water vapor is 250 ° C. or higher, the ability to remove monosilane sharply decreases. This is probably because chemisorbed water does not easily adhere to activated alumina at such temperatures.

From the results shown in Table 4, when the activated alumina from which the physically adsorbed water has been removed is brought into contact with water vapor under the temperature condition of 100 to 200 ° C., the activated alumina is activated thereby, which is effective in removing the gaseous silicon compound. Was found. Therefore, as a removing agent for the gaseous silicon compound,
After removing the physically adsorbed water as needed, 100 to 20
It can be seen that the gaseous silicon compound can be efficiently removed by using activated alumina obtained by contacting water vapor under the temperature condition of 0 ° C.

In the above test example, the contact time between activated alumina and water vapor was set to 1 hour, but when dry activated alumina and water vapor are contacted with each other, heat is generated, and the heat generated from the inlet side to the outlet side of the filling cylinder 3. Since a plurality of temperature measuring elements are arranged in the flow direction on the side surface of the filling cylinder 3, the temperature rises once on the gas outlet pipe 2 side, and when the temperature decreases, the activated alumina in the filling cylinder 3 It may be determined that water has been chemically adsorbed to all of the above, and the contact treatment with water vapor may be terminated.

In the above test example, the activated alumina is dried to remove the physically adsorbed water before the activated alumina is contacted with water vapor. However, the activated alumina used is not sufficiently dried. It may be carried out only when it is judged that it is sufficient. If it is in a sufficiently dried state, it may be activated immediately by contacting it with steam at the predetermined temperature. That is, the physically adsorbed water may be removed as necessary.

Further, in the case of removing the physically adsorbed water, dry nitrogen gas was contacted in the above test example.
Any fluid can be used, and other appropriate drying means such as not only contact drying but also reduced pressure drying may be used.

Although the above test is for activated alumina (γ alumina), the same effect can be obtained for other α alumina and β alumina. However, it is preferable to use γ-alumina because it is naturally advantageous that the surface area is large when it is used as a harmful agent. Similar results can be obtained with any aluminum oxide other than activated alumina. It is considered that this is because aluminum in the substance has a great influence on the removal of the gaseous silicon compound.

The above has been described in terms of the safety of the exhaust gas by removing the gaseous silicon compound in the exhaust gas, but the present invention is
The present invention is not limited to this, and can also be used for purification operations such as removal of gaseous silicon compounds contained as impurities in arsine or phosphine.

[0036]

As described above, according to the present invention,
Aluminum oxide from which physically adsorbed water has been removed if necessary 1
Since aluminum oxide can be activated by contacting with water vapor under a temperature condition of 00 to 200 ° C., the ability of aluminum oxide to remove a gaseous silicon compound can be reproducibly and maximally improved.

[Brief description of drawings]

FIG. 1 is a system diagram of a test apparatus used in an example of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Gas inlet pipe, 2 ... Gas outlet pipe, 3 ... Filling cylinder, 4 ... Heating means, 6 ... Sample gas filling container, 8 ... Pure water tank, 10
... Bypass path, 11 ... Purge gas filling container, 12 ... Analyzer, 13 ... Thermometer, 14 ... Temperature control means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location B01J 20/08 ZAB A 7202-4G H01L 21/205 ZAB

Claims (3)

[Claims] 1. Aluminum oxide at 100 to 200 ° C.
A method for removing a gaseous silicon compound, comprising contacting water vapor under the temperature condition of 1, and then contacting a gas containing a gaseous silicon compound. 2. Aluminum oxide at 100 to 200 ° C.
A removing agent for a gaseous silicon compound, which is obtained by contacting with steam under the temperature condition of. 3. Aluminum oxide at 100 to 200 ° C.
A method for producing a gaseous silicon compound removing agent, which comprises contacting with steam under the temperature condition of.