JP3703406B2 - Reactive fluorine gas removal treatment agent and reactive fluorine gas removal method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the present invention, when reactive fluorine-based gases such as hydrogen fluoride, fluorine, tungsten hexafluoride, silicon tetrafluoride, and boron trifluoride used mainly in semiconductor manufacturing processes are discharged, The present invention relates to an abatement treatment agent and an abatement method for detoxifying a system gas.
[0002]
[Prior art]
In the semiconductor industry, reactive fluorine-based gases are used in semiconductor manufacturing processes such as CVD, vacuum deposition, and sputtering. Also, in the process of using a stable fluorine compound such as PFC (perfluoro compound gas), a reactive fluorine-based gas is by-produced by plasma.
Conventionally, when the reactive fluorine-based gas is discharged, a detoxification process is performed in which the reactive fluorine-based gas is brought into contact with a treatment agent to be absorbed and detoxified.
As this detoxifying agent, soda lime containing calcium hydroxide (Ca (OH) ₂ ) as a main component is often used.
[0003]
[Problems to be solved by the invention]
However, since the abatement treatment agent used in this treatment method has a low ability to absorb reactive fluorine-based gas, an abatement treatment agent with higher treatment capability has been desired.
The present invention has been made in view of the above circumstances, and provides a reactive fluorine-based gas removal treatment agent and a reactive fluorine-based gas removal method excellent in reactive fluorine-based gas removal treatment capability. For the purpose.
[0004]
[Means for Solving the Problems]
To solve this problem,
The invention according to claim 1 is obtained by contacting a treating agent mainly composed of calcium hydroxide with a carbon dioxide-containing nitrogen gas having a carbon dioxide concentration of 100 ppm to 500 ppm. It is a detoxifying agent for reactive fluorine-based gas.
[0005]
In the invention according to claim 2, after the treatment agent containing calcium hydroxide as a main component is contacted with a carbon dioxide-containing nitrogen gas having a carbon dioxide concentration of 100 ppm to 500 ppm, the treatment agent is reacted with a reactive fluorine-based gas. This is a method for removing reactive fluorine-based gas, which comprises subjecting a gas containing hydrogen to contact treatment.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The reactive fluorine-based gas detoxifying agent of the present invention is a detoxifying agent for detoxifying reactive fluorine-based gas contained in a gas discharged from a semiconductor manufacturing process or the like, and is mainly composed of calcium hydroxide. A treatment agent (hereinafter sometimes referred to as a calcium hydroxide-containing treatment agent or a treatment agent ) as a component is obtained by contacting with a carbon dioxide-containing nitrogen gas having a carbon dioxide concentration of 100 ppm to 500 ppm . As the calcium hydroxide-containing treatment agent, one containing soda lime can be used.
[0009]
At this time, by setting the CO ₂ concentration in the carbon dioxide (CO ₂ ) -containing nitrogen gas to 100 ppm or more and 500 ppm or less, it is possible to increase the detoxification processing capacity of the reactive fluorine-based gas.
This is presumably because part of the calcium hydroxide-containing treatment agent is converted to calcium carbonate by CO ₂ , whereby fine cracks occur on the surface due to volume expansion and the surface area increases.
If the CO ₂ concentration is less than the above range, a sufficient effect of increasing the detoxification treatment capacity cannot be obtained. On the other hand, when the CO ₂ concentration exceeds the above range, the calcium carbonate-containing treatment agent becomes excessively converted to calcium carbonate, and the detoxification treatment ability of the reactive fluorine-based gas is lowered.
[0010]
Hereinafter, an example of a method for detoxifying reactive fluorine-based gas using the reactive fluorine-based gas detoxifying agent of the present invention will be described.
As shown in FIG. 1, a filling agent 1 is filled with a calcium hydroxide-containing treatment agent (for example, soda lime) M.
The valves 2 and 3 are opened, the valves 12 and 13 are closed, and carbon dioxide-containing nitrogen gas Ng is introduced into the filling cylinder 1 from the pipe 4 via the valve 2 and the pipe 5, and the pipe 6, Derived via the valve 3 and the conduit 7. As a result, the treatment agent M in the filling cylinder 1 is brought into contact with the carbon dioxide-containing nitrogen gas Ng to obtain the detoxification treatment agent M0.
By bringing the treatment agent M into contact with the carbon dioxide-containing nitrogen gas , the moisture-containing component covering the treatment agent M can be removed. For this reason, the abatement treatment agent M0 with the surface of the treatment agent M exposed is obtained.
[0011]
Next, the valves 2 and 3 are closed, and the introduction of the carbon dioxide-containing nitrogen gas Ng into the filling cylinder 1 is stopped. Next, the valves 12 and 13 are opened, and the gas Fg containing the reactive fluorine-based gas is supplied from the gas source 10 to be processed in the semiconductor manufacturing process or the like through the pipe 8, the valve 12, and the pipe 5. It introduce | transduces into the filling cylinder 1, and is made to contact the abatement treatment agent M0.
The detoxifying agent M0 is in a state in which the moisture-containing component has been removed by the carbon dioxide-containing nitrogen gas treatment, so that the reactive fluorine system in the gas Fg to be treated is not hindered by the moisture-containing component. Absorbs gas efficiently.
Therefore, the gas to be treated Fg that has passed through the filling cylinder 1 is led out as the discharge gas F0 through the pipes 6 and 9 in a state in which the reactive fluorine-based gas is removed and rendered harmless.
By performing this detoxification treatment for a long time, the detoxification treatment agent M0 is close to saturation in absorption capacity, and the concentration of the reactive fluorine-based gas in the released gas F0 increases and reaches an allowable value (for example, 3 ppm) Replaces the detoxification treatment agent M0 with a new treatment agent, and after the treatment agent is treated with the carbon dioxide-containing nitrogen gas , the treatment gas Fg is treated.
[0012]
< Reference Example 1>
Treatment agent M made of soda lime was filled into a filling cylinder 1 having a diameter of 40 mm so as to have a height of 20 cm.
Nitrogen Ng was introduced into the filling cylinder 1 at a flow rate of 20 L / min over 24 hours, and this nitrogen was brought into contact with the treating agent M to obtain a detoxifying agent M0.
Using the apparatus shown in FIG. 1, the gas to be treated Fg shown below was caused to flow through the filling cylinder 1 under the condition of an empty cylinder speed of 10 cm / s.
・ Hydrogen fluoride (HF): 1.5% by volume
・ Silicon tetrafluoride (SiF ₄ ): 0.6% by volume
Nitrogen gas (N ₂ ): 97.9% by volume
As a result of measuring the hydrogen fluoride (HF) concentration in the released gas F0 from the pipe 9 with the gas detector, the time until the hydrogen fluoride (HF) concentration in the released gas F0 reaches the allowable concentration (3 ppm) ( The breakthrough time was 400 hours.
[0013]
< Reference Example 2>
The same treatment agent M as that used in Reference Example 1 was left in the atmosphere for 24 hours, and then filled into a filling cylinder 1 having a diameter of 40 mm so as to have a height of 20 cm.
Nitrogen was introduced into the filling cylinder 1 at a flow rate of 20 L / min over 24 hours to obtain a detoxifying agent M0.
When the gas Fg having the same composition as that used in Reference Example 1 was allowed to flow through the filling cylinder 1 at the same cylinder speed as in Reference Example 1, the breakthrough time was 530 hours.
[0014]
< Reference Example 3>
The same treatment agent M as that used in Reference Example 1 was filled as it was in a filling cylinder 1 having a diameter of 40 mm to a height of 20 cm.
Dry gas was introduced into the filling cylinder 1 at a flow rate of 8 L / min for 24 hours to obtain a detoxifying agent M0.
When the gas Fg having the same composition as that used in Reference Example 1 was allowed to flow through the filling cylinder 1 at the same cylinder speed as in Reference Example 1, the breakthrough time was 530 hours.
[0015]
<Example>
The same treatment agent M as that used in Reference Example 1 was filled as it was in a filling cylinder 1 having a diameter of 40 mm to a height of 20 cm.
Nitrogen gas containing 100 ppm of carbon dioxide was introduced into the filling cylinder 1 at a flow rate of 20 L / min for 24 hours to obtain a detoxifying agent M0.
When the gas Fg having the same composition as that used in Reference Example 1 was allowed to flow through the filling cylinder 1 at the same cylinder speed as in Reference Example 1, the breakthrough time was 500 hours.
[0016]
<Comparative example>
The same treatment agent M as that used in Reference Example 1 was directly filled in a filling cylinder 1 having a diameter of 40 mmφ to a height of 20 cm.
The treatment agent M without performing the processing of contacting the carbon dioxide-containing nitrogen gas Ng, the treated gas Fg of the same composition as that used in Reference Example 1, was passed to the filling tube 1 at the same superficial speed as in Reference Example 1 However, the breakthrough time was 180 hours.
[0017]
As described above, it was found that in the example in which the carbon dioxide-containing nitrogen gas treatment was performed, the life of the detoxifying agent M0 was greatly extended compared to the comparative example in which the carbon dioxide-containing nitrogen gas treatment was not performed.
The reactive fluorine-based gas to be treated in the present invention is not limited to the above-mentioned hydrogen fluoride and silicon tetrafluoride, but reactive gases such as fluorine, tungsten hexafluoride, boron trifluoride and the like. The same detoxification effect can be obtained with any fluorine compound.
[0018]
【The invention's effect】
The reactive fluorine gas detoxifying agent of the present invention is obtained by bringing a treating agent mainly composed of calcium hydroxide into contact with carbon dioxide-containing nitrogen gas having a carbon dioxide concentration of 100 ppm to 500 ppm. So you can get excellent abatement ability. Furthermore, it is possible to significantly extend the useful life of the abatement treatment, and to reduce the operating cost.
[Brief description of the drawings]
FIG. 1 is a system diagram showing a reactive fluorine-based gas removal apparatus capable of implementing the reactive fluorine-based gas removal method of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Filling cylinder, 10 ... To-be-processed gas source, M ... Treatment agent which has calcium hydroxide as a main component, M0 ... Detoxification treatment agent, Ng ... Nitrogen containing gas (gas containing nitrogen), Fg ... Reactive fluorine type Processed gas containing gas, F0 ... released gas

Claims (2)

Detoxification of reactive fluorine-based gas characterized by being obtained by contacting a treatment agent mainly composed of calcium hydroxide with carbon dioxide-containing nitrogen gas having a carbon dioxide concentration of 100 ppm to 500 ppm. Processing agent. After treating the treatment agent containing calcium hydroxide as a main component with a carbon dioxide-containing nitrogen gas having a carbon dioxide concentration of 100 ppm to 500 ppm, the treatment agent is contacted with a gas containing a reactive fluorine-based gas. A method for removing reactive fluorine-based gas, characterized in that

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