JP2001248821A - Equipment for waste gas treatment in semiconductor production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an equipment for waste gas treatment in a semiconductor production in which waste gas silane(SiH4) in a semiconductor production process is subjected to a combustion treatment in advance, and the gas is sent to a waste gas treating equipment for decomposition of fluorocarbon(PFC) of an original treatment target, and silica is prevented from adhering on a silane decomposition apparatus and a fluorocarbon decomposition apparatus. SOLUTION: In an equipment for detoxification treatment of waste gas in a semiconductor production for treating waste gas containing at least fluorocarbon(PFC) and silane(SiH4), a silane-treating equipment is disposed in a preceding stage to another waste gas treatment equipment for treating fluorocarbon. The silane-treating equipment comprises a silane-containing waste gas inlet 2, an ignition burner 1, and a combustion air inlet 3. The waste gas inlet 2 is inserted in the inside of the silane treating equipment, and the outlet from the waste gas inlet 2 is positioned downstream of the ignition burner 1, the outlet of the combustion air inlet 3 is positioned downstream of the outlet of the waste gas inlet 2, and the combustion air is mixed with the waste gas in the downstream side of the outlet from the waste gas inlet 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for treating exhaust gas from semiconductor manufacturing, and more particularly to a means for efficiently and safely burning and removing silane from exhaust gas generated in a semiconductor manufacturing process.

[0002]

2. Description of the Related Art In recent years, the problem of global warming has been highlighted, and it has been required to suppress the emission of exhaust gas such as carbon monoxide and carbon dioxide generated by consuming a large amount of fossil fuel. ing.

Freon discharged from semiconductor manufacturing process
(PFC: Perfluorocarbon)
Although the total usage is small, the global warming potential
It is said to be 1,000 times to 10,000 times, and it cannot be ignored if semiconductor production is expected to increase in the future. Therefore, there is a need to develop an exhaust gas treatment device that renders chlorofluorocarbon harmless.

[0004] Exhaust gas from the semiconductor manufacturing process contains harmful components such as silane in addition to chlorofluorocarbons. The semiconductor manufacturing exhaust gas treatment apparatus includes a process for decomposing chlorofluorocarbons and a process for decomposing harmful gases such as silane. Must be added.

As shown in FIG. 3, exhaust gas such as silane discharged from a reactor in a semiconductor manufacturing plant is processed by a single exhaust gas treatment device 8 for a plurality of reactors 6. That is, a plurality of lines including the reactor 6 and the pump 7 are integrated into one system, and are introduced into the exhaust gas treatment device 8 in a switching manner. Exhaust gas such as silane is highly toxic. In particular, silane gas has a property of being ignited when exposed to air. Therefore, it is necessary to provide a treatment device for removing silane before introducing the exhaust gas into the CFC decomposition device.

In conventional methods for removing silane,
When exhaust gas is ejected from the tip of a burner nozzle disposed in an exhaust gas treatment device, air is sent, burned and oxidized, and discharged as harmless gas from the exhaust gas treatment device.

[0007]

However, when the silane gas is burned, a large amount of silica (SiO ₂ ) is generated. This silica is a fine powder, and if it is treated using a normal burner nozzle, the silica will clog the pores of the nozzle and cause poor combustion.

An object of the present invention is to provide a semiconductor manufacturing exhaust gas treatment apparatus having a structure capable of preventing adhesion of silica, which is a combustion product, in an apparatus for burning and treating silane contained in exhaust gas of a semiconductor manufacturing process.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a semiconductor manufacturing exhaust gas treatment for detoxifying an exhaust gas discharged from a semiconductor manufacturing apparatus and containing at least freon (PFC) and silane (SiH ₄ ). In the apparatus, a silane treatment apparatus for treating silane is disposed at a stage before the exhaust gas treatment apparatus for treating chlorofluorocarbons, and the silane treatment apparatus connects an exhaust gas inlet containing silane, an ignition burner, and a combustion air introduction port. The exhaust gas inlet is inserted up to the inside of the silane treatment device, the outlet of the exhaust gas inlet is located downstream of the ignition burner, and the outlet of the combustion air inlet is larger than the outlet of the exhaust gas inlet. A semiconductor manufacturing exhaust gas treatment device located downstream is proposed.

[0010] As described above, the exhaust gas inlet to the exhaust gas treatment device is inserted into the silane treatment device so that the upper portion of the silane treatment device is not mixed with the combustion air downstream of the exhaust gas inlet. Thereby, the adhesion of silica at the outlet of the exhaust gas inlet can be reliably prevented.

The theoretical air ratio of the ignition burner is less than 1.0.

At a stoichiometric air ratio in this range, it is possible to prevent the exhaust gas inlet from being clogged by the silica produced by combustion and to maintain a stable combustion state.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a semiconductor manufacturing exhaust gas treatment apparatus according to the present invention will be described with reference to FIGS. FIG. 1 is a longitudinal sectional view showing a schematic structure of an embodiment of a semiconductor manufacturing exhaust gas treatment apparatus according to the present invention, and FIG.
It is a longitudinal cross-sectional view explaining the positional relationship of the inlet in the uppermost part of the semiconductor manufacturing exhaust gas processing apparatus of FIG.

The semiconductor manufacturing exhaust gas treatment apparatus of this embodiment is
The plane cross section is substantially cylindrical, and an ignition burner 1, an exhaust gas inlet 2, and a combustion air inlet 3 are provided at the top. An exhaust gas outlet 4 is provided below the exhaust gas treatment device, and the exhaust gas from which silane has been rendered harmless flows out from the exhaust port 4 to the original fluorocarbon decomposition treatment device. The lowermost part of the exhaust gas treatment device is a hopper, and a water seal device 5 is provided below the hopper to collect silica generated by combustion.

As shown in FIG. 2, the flow paths of the three types of gas at the uppermost part of the exhaust gas treatment device are concentrically divided, and the ignition burner 1, exhaust gas inlet 2, combustion Service air inlets 3 are sequentially arranged. Also, the outlet of the exhaust gas inlet 2 is
It is downstream of the ignition burner 1 and has a combustion air inlet 3
Exit is further downstream. When the air ratio of the ignition burner 1 is set to 0.8 to 0.9, the exhaust gas containing silane is ignited on the downstream side of the outlet of the exhaust gas inlet 2 when mixed with the combustion air. Therefore, it is possible to reliably prevent the exhaust gas inlet 2 from being clogged by the silica generated by the combustion.

In the silane treatment apparatus according to the present invention, the exhaust gas is burned. However, the combustion is not performed for the purpose of decomposing CFCs. There is no need for high temperatures and a small amount of fuel is sufficient.

The harmless exhaust gas from which silane has been removed flows from the discharge port 4 to the original fluorocarbon decomposition apparatus. Also,
Silica generated by the combustion is collected by a water seal device 5 provided at a lower portion of the exhaust gas treatment device.

[0018]

According to the present invention, a silane treatment apparatus for treating silane is disposed at a stage prior to an exhaust gas treatment apparatus for treating chlorofluorocarbon, and the exhaust gas inlet of the silane treatment apparatus extends to the inside of the silane treatment apparatus. Inserted, the outlet of the exhaust gas inlet is located downstream of the ignition burner, and the outlet of the combustion air inlet is obtained downstream of the exhaust gas inlet. Since no stagnation is generated, adhesion of silica can be reliably prevented.

The end of the exhaust gas inlet is downstream of the ignition burner, and the combustion air supplied from outside the circumference where the exhaust gas inlet is arranged mixes with the exhaust gas downstream of the end of the exhaust gas inlet. Therefore, clogging of the exhaust gas inlet with silica generated by combustion can be prevented.

As a result of setting the stoichiometric air ratio of the ignition burner to less than 1.0, it is possible to prevent the exhaust gas inlet from being clogged with silica generated by combustion and to maintain a stable combustion state.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a schematic structure of an embodiment of a semiconductor manufacturing exhaust gas treatment apparatus according to the present invention.

FIG. 2 is a longitudinal sectional view for explaining a positional relationship of an inlet at an uppermost portion of the semiconductor manufacturing exhaust gas treatment apparatus of FIG.

FIG. 3 is a diagram showing an example of a system configuration from a plurality of reactors to one exhaust gas treatment device in a conventional semiconductor manufacturing process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ignition burner 2 Exhaust gas inlet 3 Combustion air inlet 4 Exhaust gas outlet 5 Water seal device 6 Reactor 7 Pump 8 Exhaust gas treatment device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Noriyuki Oyatsu 3-36 Takara-cho, Kure-shi, Hiroshima Babcock-Hitachi Inside Kure Research Laboratory (72) Inventor Noboru Takayama 3-36 Takara-cho, Kure-shi, Hiroshima Babcock-Hitachi Co., Ltd. (72) Inventor Miki Shimogori 3-36 Takara-cho, Kure-shi, Hiroshima Babcock-Hitachi Kure Research Laboratory F term (reference) 3K078 AA07 BA20 BA21 BA29 CA01 CA09

Claims (2)

[Claims] 1. A semiconductor manufacturing exhaust gas treatment apparatus for detoxifying an exhaust gas discharged from a semiconductor manufacturing apparatus and containing at least chlorofluorocarbon (PFC) and silane (SiH ₄ ), in a stage prior to an exhaust gas treatment apparatus for treating chlorofluorocarbons. A silane treatment device for treating silane is disposed, wherein the silane treatment device has an exhaust gas inlet including silane, an ignition burner, and a combustion air inlet, and the exhaust gas inlet extends to the inside of the silane treatment device. The outlet of the exhaust gas inlet is located downstream of the ignition burner, and the outlet of the combustion air inlet is located downstream of the outlet of the exhaust gas inlet. Semiconductor manufacturing exhaust gas treatment equipment. 2. The exhaust gas treating apparatus for semiconductor manufacturing according to claim 1, wherein a theoretical air ratio of the ignition burner is less than 1.0.