JPH0344252Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an apparatus for processing gases used in the manufacture of semiconductor devices, particularly pyrophoric silane-based gases.

[Conventional technology]

In chemical vapor deposition (CVD) processes for manufacturing semiconductor devices, pyrophoric silane gases such as SiH ₄ and SiH ₂ Cl ₂ are used. For example, for SiH ₄ , H ₂ base SiH ₄ has approx.
It spontaneously ignites at 0.5%, and spontaneously ignites at about 4% for N2 _- based _SiH4 . Therefore, it is extremely important to safely treat waste gas containing partially unreacted SiH ₄ after the CVD process from the viewpoint of preventing factory accidents. Methods for treating such silane-based waste gas are broadly classified into three types: a treatment method using a combination of oxidation adsorption and alkali cleaning, a combustion treatment method, and a hydrolysis treatment method. Among these, the hydrolysis treatment method (see Japanese Unexamined Patent Publication No. 51-105679 and Japanese Utility Model Publication No. 53-27961) utilizes the reaction of SiH ₄ +2H ₂ O→SiO ₂ +4H ₂ . Such a reaction is difficult to occur simply by exposure to water, and a sufficient hydrolysis effect cannot be expected. However, if a treatment device called a scrubber is used, which exposes the waste gas to water and dilutes it with a large amount of air, the concentration will be below the current permissible concentration of 5.0 ppm when discharged from the scrubber. Waste gas can be safely treated. The conditions that such a scrubber must have in order to dilute the waste gas to below the standard concentration are that the waste gas must be diluted with _N2 to 1% or less before being introduced into the scrubber, and that the waste gas must be diluted with a large amount of air within the scrubber. or by spraying water where the waste gas and air come into contact.

[Problem that the invention attempts to solve]

The treatment method using a scrubber is cheaper than the treatment method using a combination of oxidation adsorption and alkaline cleaning, and the heat treatment method, and sufficient dilution effect can be obtained by devising the equipment and method of use. It is advantageous to use However, in conventional scrubbers, there was no means to deal with abnormalities in the waste gas treatment means that diluted the waste gas with air and exposed it to the cleaning liquid. There was a risk of spontaneous combustion due to increased concentration of waste gas. Abnormalities in the waste gas processing means include, for example, failure of the blower that supplies air to the scrubber, failure of the exhaust gas exhaust fan, failure due to blockage or breakage of the processing chamber, failure of the cleaning liquid supply system, and the like.

The present invention provides an exhaust gas treatment device that can safely treat waste gas by operating another treatment means even if an abnormality occurs in the original exhaust gas treatment means.

[Means for solving problems]

The present invention has a pipe for introducing waste gas, a pipe for supplying air, a pipe for supplying cleaning liquid that splits into two from the middle, and a bubbling plate as a filter that separates the processing chamber, and the waste gas is The waste gas introduced through the introduction pipe is diluted with the air supplied to the air supply pipe, and is exposed to the atomized cleaning liquid supplied by the cleaning liquid supply pipe at the bubbling plate. , a waste gas treatment unit having first and second cleaning liquid supply pipes that spray cleaning liquid from both sides of the bubbling plate toward the bubbling plate, and an abnormality in the waste gas treatment unit; The bypass pipe is configured to discharge waste gas from the waste gas processing section to the waste gas discharge pipe when the waste gas is generated.

[Effect]

In the present invention having such a configuration, various abnormalities may occur in the waste gas processing section, such as failure of the blower, failure of the exhaust gas exhaust fan, failure due to blockage or damage to the processing chamber, failure of the cleaning liquid supply system, etc. When this occurs, the bypass pipe is activated and the waste gas from the waste gas treatment section is discharged to the waste gas discharge pipe. Therefore, the waste gas supplied when the waste gas treatment section is abnormal is discharged to the outside of the apparatus from the waste gas exhaust pipe without remaining within the apparatus.

In addition, since the bubbling plate as a filter is exposed to a mist of cleaning liquid,
The waste gas comes into contact with the cleaning liquid via a large wetted contact surface.

Furthermore, since the cleaning liquid is sprayed toward the bubbling plate from both sides of the bubbling plate, SiO ₂ attached to both sides of the bubbling plate is completely removed.

〔Example〕

Embodiments of the present invention will be described with reference to the schematic diagrams of the drawings.

A processing chamber 1, which is a so-called scrubber and constitutes the main part of the waste gas processing section of the apparatus of this embodiment, is provided with a pipe 2 for introducing waste gas led from a CVD apparatus (not shown). In addition, a blower 6 that communicates with this processing chamber 1
A differential pressure gauge 15 is installed in the air supply pipe 3, and a fan 5 is installed at the contact portion between the processing chamber 1 and the waste gas discharge pipe 4. The cleaning liquid supply system is divided into a cleaning liquid tank 7, a drive source 8 for supplying the cleaning liquid from the tank 7, and a bubbling plate as a filter for the processing chamber 1 through a valve 9. 10 so that the cleaning liquid is sprayed toward the bubbling plate 10 from below,
The other is constituted by a cleaning liquid supply pipe 13 through which the cleaning liquid is sprayed from above the bubbling plate 10 toward the bubbling plate 10 through a valve 11 and a flow meter 12. The reason why the cleaning liquid is sprayed from both sides toward the bubbling plate 10 is to completely prevent the bubbling plate 10 from being clogged with SiO ₂ powder generated by the oxidation reaction between SiH ₄ and air. This is to prevent the bubbling plate 10 from burning due to reaction heat. The cleaning liquid accumulated in the processing chamber 1 is returned to the tank 7. An appropriate cleaning liquid is used depending on the type of waste gas, but for example, in the case of pyrophoric waste gas, it is preferably about 5% alkali or hydrofluoric acid.

In this embodiment, a bypass pipe 14 is provided which communicates with the waste gas discharge pipe 4 from below the processing chamber 1, and various abnormalities in the waste gas processing section are installed in the middle of the bypass pipe 14. A valve 16 is provided which is configured to open automatically if this occurs. As a result, if a failure occurs in the blower 6, fan 5, or cleaning liquid supply system, for example, the valve 16 will automatically open, and the waste gas will pass through the bypass pipe 14 and be discharged from the waste gas discharge pipe 4 to the outside of the device. be done. An abnormality in the blower 6 or the fan 5 is detected by a differential pressure gauge 15, and this differential pressure gauge 15 is interlocked with a valve 16. In addition,
If the blower 6 malfunctions, it will be discharged outside the device without being diluted with air, but if the fan 5 or the cleaning fluid supply system malfunctions, the blower 6 will operate normally and dilution with air will not be performed. After that, it is discharged to the outside of the device through the bypass pipe 14.

Note that it is preferable that the power source is a dual power source system of commercial power supply and private power generation, so that in the event of a power outage of the commercial power supply, the system automatically switches to private power generation. In addition, install a power outage alarm device, a washing water outage alarm device (installation location is, for example, a flow meter), an air outage alarm device (in an installation location, for example, an air supply pipe), and a temperature rise alarm device (in an installation location, for example, an air supply pipe) at appropriate locations within this device. It is preferable to provide a location (for example, a processing chamber) and to link these with the gas control power source of the CVD apparatus. That is, if these alarm devices indicate an abnormality, the gas supply to the CVD device is automatically stopped or restricted.

[Effect of idea]

According to this waste gas treatment device, even if an abnormality occurs in the waste gas treatment section, the waste gas will not remain in the device and will be discharged to the outside, so the concentration of waste gas will not increase inside the device. The risk of spontaneous combustion is avoided.

In addition, since the bubbling plate as a filter is exposed to a mist of cleaning liquid,
The waste gas comes into contact with the cleaning liquid via a large wetted contact surface, so that the waste gas and the cleaning liquid react efficiently.

Furthermore, since the cleaning solution is sprayed toward the bubbling plate from both sides of the bubbling plate, SiO ₂ adhering to both sides of the bubbling plate is completely removed, which prevents clogging of the bubbling plate and cleans it naturally. Ignition can be avoided, and since the bubbling plate is cooled by the cleaning liquid, spontaneous ignition due to an increase in the temperature of the bubbling plate can be prevented, and even if a fire does occur, it can be extinguished.

[Brief explanation of drawings]

The drawing is a schematic diagram of the present waste gas treatment device. 1 is a processing chamber, 2 is a waste gas introduction pipe, 3 is an air supply pipe, 4 is a waste gas discharge pipe, 10
1 is a bubbling plate, 13 is a cleaning liquid supply pipe, 1
4 is a bypass pipe.

Claims (1)

[Scope of utility model registration request] A waste gas introduction pipe, an air supply pipe,
A cleaning liquid supply pipe that splits into two from the middle,
It has a bubbling plate as a filter that separates the processing chamber, and the waste gas introduced through the waste gas introduction pipe in the processing chamber is diluted with the air supplied to the air supply pipe,
The bubbling plate is exposed to the atomized cleaning liquid supplied by the cleaning liquid supply pipe, and the cleaning liquid supply pipe sprays the cleaning liquid toward the bubbling plate from both sides of the bubbling plate. and a waste gas processing section having a second cleaning liquid supply pipe, and when an abnormality occurs in the waste gas processing section, waste gas is discharged from the waste gas processing section to the waste gas discharge pipe. A waste gas treatment device having a bypass pipe.