JP2003068595A - Semiconductor production facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor production facility as a total system where by-product gas, i.e., oxygen rich air, from a cryogenic separation nitrogen production system provided in combination with a facility for making harmless the exhaust gas from a semiconductor production system or a liquid crystal production system using high purity nitrogen gas through a combustion type unharming system can be utilized effectively. SOLUTION: The semiconductor production facility comprises a semiconductor production system 10 using high purity nitrogen gas, a combustion type unharming system 11 for making harmless the exhaust gas from the semiconductor production system 10 by combustion flame using oxygen rich air as combustion assist gas, and a cryogenic separation nitrogen production system 12 for producing oxygen rich air being used in the combustion unharming system 11 plus high purity nitrogen gas being used in the semiconductor production system 10. The semiconductor production facility is further comprises means 16 for regulating the oxygen concentration of oxygen rich air being supplied, as combustion assist gas, from the cryogenic separation nitrogen production system 12 to the combustion type unharming system 11 to a level suitable as the combustion assist gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing facility, and more particularly to a semiconductor manufacturing facility in which a combustion-type abatement system is used to perform a detoxification process of exhaust gas discharged from a semiconductor manufacturing system using high-purity nitrogen gas. .

[0002]

2. Description of the Related Art Exhaust gas discharged from a semiconductor manufacturing apparatus, a liquid crystal manufacturing apparatus or the like using high-purity nitrogen gas (in the present invention, these are collectively referred to as semiconductor manufacturing apparatus) , Silane, arsine, phosphine, hydrogen sulfide, hydrogen selenide, boron trifluoride, boron trichloride, silicon tetrafluoride, dichlorosilane, trichlorosilane, silicon tetrachloride, trichloroarsine, tetraethoxysilane (TEOS), hexafluoride Special material gas such as tungsten oxide, CF ₄ used for etching,
Since perfluoro compound gas (PFC) such as C ₂ F ₆ , C ₃ F ₈ , CHF ₃ and NF ₃ is contained, the exhaust gas containing these is detoxified (detoxification treatment) before being released to the outside. ) Is required, and a combustion-type abatement device is used as one of the devices for abatement processing.

This combustion-type abatement system has an advantage that PFCs, which are difficult to treat by ordinary abatement treatment, can be treated by forming a high-temperature combustion flame by using oxygen-enriched air as a combustion-supporting gas. have. In addition, when oxygen-enriched air is used, not only is a combustion flame at a higher temperature obtained than when air is used as a combustion-supporting gas, but fuel is reduced by improving combustion efficiency and the amount of nitrogen is small. The effect of suppressing the generation of NOx can be obtained.

The oxygen concentration of the oxygen-enriched air used in the combustion type abatement system is generally about 23 to 60%, preferably 2%.
It is a gas having an oxygen concentration of about 3 to 45%, and conventionally, high-concentration oxygen having an oxygen concentration of 95% or more generated by an oxygen production apparatus such as a cryogenic separation method or PSA is used in a combustion-type abatement apparatus. Immediately before, it was mixed with air to be diluted to a predetermined oxygen concentration. For this reason, not only the cost for obtaining high-concentration oxygen but also the compressor and piping for supplying the diluting air need to be installed, and the equipment cost and operating cost of these are enormous.

On the other hand, in the deep-separation-type nitrogen producing apparatus for producing the high-purity nitrogen, the oxygen concentration from the bottom of the rectification column is 25
-40% oxygen-enriched liquefied air can be obtained. This oxygen-enriched liquefied air is depressurized to atmospheric pressure and becomes a cold heat source of the condenser, or is introduced into the expansion turbine and expanded to atmospheric pressure. As a result, after becoming a cold source for generating cold, it was discharged as a waste gas to the outside of the device at about atmospheric pressure. When such waste gas under atmospheric pressure is used as combustion-supporting gas, etc., it is necessary to increase the pressure to an appropriate pressure, but the compression of oxygen-enriched gas requires a high facility cost for safety measures. There is. Furthermore, this waste gas
There is also a drawback that the oxygen concentration changes depending on operating conditions such as the nitrogen production amount in the cryogenic separation type nitrogen production apparatus.

Therefore, the present invention, when the exhaust gas from a semiconductor manufacturing apparatus or a liquid crystal manufacturing apparatus that uses high-purity nitrogen gas is detoxified by a combustion-type abatement device, is subjected to deep-chill separation for generating high-purity nitrogen gas. It is an object of the present invention to provide a semiconductor manufacturing facility as a total system that can effectively use oxygen-enriched air that is a by-product gas of a nitrogen production system.

[0007]

In order to achieve the above object, the semiconductor manufacturing equipment of the present invention is a semiconductor manufacturing apparatus using high-purity nitrogen gas, and exhaust gas discharged from the semiconductor manufacturing apparatus as a combustion supporting gas. Combustion type detoxification device that burns and decontaminates with a combustion flame using oxygen-enriched air, and oxygen-enriched air used in the combustion type detoxification device while producing high-purity nitrogen gas used in the semiconductor manufacturing device And a cryogenic separation type nitrogen production device for producing
In particular, a means for adjusting the oxygen concentration of the oxygen-enriched air supplied to the combustion-type detoxification device from the deep-separation-type nitrogen production device is provided between the deep-separation-type nitrogen production device and the combustion-type detoxification device. It is characterized by having. Further, a path for supplying a part of the oxygen-enriched air after the oxygen concentration adjustment as a combustion supporting gas for the boiler is branched downstream of the means for adjusting the oxygen concentration of the oxygen-enriched air. The semiconductor manufacturing facility according to claim 1.

In the present invention, the deep-separation-type nitrogen producing apparatus comprises a raw material air compressor for compressing raw material air,
A purifier for purifying the compressed raw material air, a heat exchanger for cooling the purified raw material air by exchanging heat with a return gas such as a product gas, and nitrogen for liquefied rectification of the cooled raw material air. A rectification column for separating gas and oxygen-enriched liquefied air,
The raw material air is provided with a condenser that heat-exchanges the nitrogen gas and the oxygen-enriched liquefied air to condense the nitrogen gas and vaporizes the oxygen-enriched liquefied air, and an expansion turbine that generates cold. An air compressor, a path introduced into the rectification column through the purifier and the heat exchanger,
A path in which the nitrogen gas is discharged from the rectification column, passes through the heat exchanger, reaches room temperature, and is taken out as product nitrogen.
A path in which the oxygen-enriched liquefied air is discharged from the rectification column and vaporized in a condenser to become oxygen-enriched air, and then is passed through the heat exchanger to reach room temperature to be taken out as a product oxygen-enriched gas; In the product oxygen-enriched gas path, the path branched from the middle part of the heat exchanger to introduce a part of the oxygen-enriched air into the expansion turbine, and the oxygen-enriched air exiting the expansion turbine are It is characterized in that it has a path through which it becomes normal temperature through the heat exchange and is taken out as exhaust gas.

Further, the path of the product oxygen-enriched gas is
A means for adjusting the oxygen concentration of the product oxygen-enriched gas after mixing is connected to the path of the purified air in the path of the raw material air and branched from the downstream side of the purifier, and to both the paths. It is characterized by that.

Further, instead of the path leading out from the heat exchanger in the path of the product oxygen-enriched gas, to the path of passing through the heat exchanger to reach room temperature and taken out as the product oxygen-enriched gas, The low-temperature oxygen-enriched gas branched from the middle part to the expansion turbine and branched before the expansion turbine is introduced is used as a product oxygen-enriched gas, and oxygen gas and / or compressed air is mixed in the path. It is characterized in that the passages are connected and a means for adjusting the oxygen concentration of the product oxygen-enriched gas after mixing is provided in each of the passages.

Further, a path for introducing liquefied nitrogen into the upper part of the rectification column is provided in place of the expansion turbine and the path for introducing the expansion turbine and the path for the exhaust gas.
A path for extracting the product oxygen-enriched gas from the outlet of the product oxygen-enriched gas path, a path for supplying compressed air and / or oxygen gas, and a path for connecting the path and the branched path And a means for adjusting the oxygen concentration of the product oxygen-enriched gas after mixing in each of the paths.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic system diagram showing an example of a semiconductor manufacturing facility according to the present invention. This semiconductor manufacturing equipment includes a plurality of semiconductor manufacturing equipments (including semiconductor manufacturing equipments, liquid crystal manufacturing equipments, and other auxiliary equipments) 10 that use high-purity nitrogen gas, and exhaust gas discharged from these semiconductor manufacturing equipments 10. Combustion-type detoxification device 11 for performing harm treatment, and cryogenic separation for producing the high-purity nitrogen gas used in the semiconductor device 10 and oxygen-enriched air used as a combustion-supporting gas for the combustion-type detoxification device 11 And a type nitrogen production device 12.

The high-purity nitrogen used in the semiconductor manufacturing apparatus 10 is manufactured by deep-chill liquefying and separating air in the deep-separation-type nitrogen manufacturing apparatus 12, and is supplied to each semiconductor manufacturing apparatus 10 via a pipeline 13. It This high-purity nitrogen is
The semiconductor manufacturing apparatus 10 is used for various purposes in various devices such as for diluting a semiconductor material gas such as silane or arsine, for a carrier of a doping gas, for purging a manufacturing line, and for atmospheres such as substrate transportation. In this,
In the thin film forming process, the doping process, the etching process, etc. in the semiconductor manufacturing apparatus 10, harmful gas such as toxic gas, corrosive gas, combustible gas, and combustion supporting gas as described above, or nonflammability that adversely affects the global environment Since gas is used, these harmful components are contained in the exhaust gas discharged from the semiconductor manufacturing apparatus 10 to the pipeline 14.

The combustion type abatement device 11 removes harmful components in the exhaust gas discharged to the pipe line 14, and is a high temperature obtained by burning a fuel such as LPG, hydrogen, natural gas or kerosene. By introducing the exhaust gas into the flame of No. 1, various harmful components existing in the exhaust gas are burned or thermally decomposed to perform the detoxification treatment. This combustion type abatement device 11
The oxygen-enriched air taken out from the cryogenic separation type nitrogen producing device 12 to the pipe 15 is mixed with the combustion-supporting gas for burning the fuel by introducing the air from the pipe 17 by the oxygen concentration adjusting means 16. However, it is used after adjusting to an appropriate oxygen concentration.

Before and after the combustion-type abatement device 11, a flow rate controller 18 for adjusting the flow rate of the combustion-supporting gas and an analyzer 19 for analyzing the concentration of a specific component in the treated gas after the abatement process are provided. Is provided, and a more reliable detoxification process can be performed by adjusting the flow rate of the combustion supporting gas by the flow rate controller 18 according to the NOx concentration, the fluoride concentration, etc. measured by the analyzer 19. . Gas after scrubbing is scrubber 2
After being subjected to a post-treatment with 0 or the like, it is released into the atmosphere from the conduit 21. Further, the analyzer 19 is connected with a pipe line 14a branched from the pipe line 14 and is formed so as to analyze the concentration of target gas to be removed, NOx concentration, and fluoride concentration in the exhaust gas before the removal process. Has been done.

The semiconductor manufacturing apparatus 10 and the combustion type detoxification apparatus 11 can use various apparatuses that have been conventionally used, and the semiconductor manufacturing apparatus 10 includes various thin film manufacturing apparatuses and vapor phase growth. For example, Japanese Patent Application Laid-Open No. 10-110926 and Japanese Patent Application Laid-Open No.
Combustion-type abatement devices having various configurations such as the combustion-type abatement device described in Japanese Patent Publication No. 001-82723 and the like can be used. In the present invention, the structure, usage method, and operation of these devices are used. Since the method is not particularly limited, detailed illustration and description of these devices are omitted.

FIG. 2 shows the deep-separation separation type nitrogen production apparatus 12
It is a systematic diagram which shows the example of a 1st form. This nitrogen production equipment 1
No. 2 produces high-purity nitrogen gas as the main product by liquefying and rectifying and separating air as a raw material in the single-rectification column 31, and at the time of separating high-purity nitrogen gas, the single-rectification column 3
The oxygen-enriched air derived as a by-product gas from No. 1 can be effectively used as a combustion-supporting gas for a combustion-type abatement device or the like.

In the nitrogen producing apparatus 12 shown in FIG. 2, the raw material air sucked from the filter 32 is compressed to a predetermined pressure by the raw material air compressor 33, and the after cooler 34 is used.
After the heat of compression is removed by the method, it is introduced into the purifier 36 through the pipe 35, and impurities such as water in the air and carbon dioxide are removed here. The purified raw material air led out of the purifier 36 is
Most of it is introduced into the heat exchanger 38 via the line 37,
Here, the product gas (high-purity nitrogen gas), which is a cold fluid, is cooled by exchanging heat with a return gas, and the conduit 39
It is introduced into the lower part of the single rectification column 31 via. By the liquefaction rectification in the rectification column 31, the raw material air is separated into nitrogen gas in the upper part of the column and oxygen-enriched liquefied air in the lower part of the column, and the rectification column 31
The nitrogen gas separated in the upper part of the is usually a high-purity nitrogen gas having a purity of 99.99% or more.

The nitrogen gas is withdrawn from the upper part of the rectification column 31 into a pipe 40, and further through a pipe 41 to the heat exchanger 3
Introduced in 8. The nitrogen gas is subjected to heat exchange with the raw material air in the heat exchanger 38 to recover cold, and then is discharged from the heat exchanger 38 to the pipe 42, where the pipe 1
It is supplied to each semiconductor manufacturing apparatus 10 through 3 respectively.

Further, a part of the nitrogen gas extracted from the rectification column 31 into the pipe 40 is branched from the pipe 40 into the pipe 43 and introduced into the condenser 44, and the oxygen-enriched liquefied air described later is obtained. The liquid is cooled and liquefied by heat exchange with liquefied nitrogen. Most of this liquefied nitrogen is introduced into the upper part of the rectification column 31 through a pipe 45 and becomes a reflux liquid for rectification. Part of the liquefied nitrogen is extracted into a pipe line 46 branched from the pipe line 45 and stored in a liquefied nitrogen storage tank 47. Further, the pipe line 46 can also be used as a pipe line for supplying the liquefied nitrogen in the liquefied nitrogen storage tank 47 to the rectification column 31 through the pipe line 45.

On the other hand, in the lower part of the rectification column 31, oxygen-enriched liquefied air having an oxygen concentration of about 25 to 45% is separated. This oxygen-enriched liquefied air is led out from the lower part of the rectification column 31 to a pipe line 48, and is decompressed by a pressure reducing valve 49 to 0.1 MPa (gauge pressure, the same applies hereinafter) or more, preferably 0.2 to 0.5 MPa. After that, it is introduced into the condenser 44 through the pipe 50, where it exchanges heat with the nitrogen gas and is heated to be vaporized to become oxygen-enriched air. Most of the oxygen-enriched air vaporized in the condenser 44 is introduced into the heat exchanger 38 via the pipe line 50 and the pipe line 51. A part of the oxygen-enriched air is branched in the middle of the heat exchanger 38 into a line 52 and introduced into an expansion turbine 53 that produces the cold required for continuing the operation of the apparatus. The remaining oxygen-enriched air that has not branched to the pipe 52 is recovered from the pipe 54 by the heat exchanger 38 after recovering the cold to normal temperature and then depressurized by the pressure reducing valve 49 while maintaining the pressure. And is introduced into the oxygen concentration adjusting means 16.

Further, the pipe line 5 in front of the pipe line 51 without going to the pipe line 51
The oxygen-enriched air branched into 5 is depressurized to the atmospheric pressure by the valve 56. On the other hand, the oxygen-enriched air that has been expanded to atmospheric pressure in the expansion turbine 53 to generate cold is merged with the oxygen-enriched air that has been decompressed by the pressure reducing valve 56 via the pipe 57, and the pipe 58.
It is again introduced into the heat exchanger 38 through the pipe, and after refrigeration is recovered by exchanging heat with the raw material air, it is extracted into the pipe 59, and a part of it is used as a regenerated gas of the purifier 36.

The oxygen-enriched air introduced into the oxygen concentration adjusting means 16 from the pipe 54 is mixed with the dilution air supplied from the pipe 17 to a predetermined oxygen concentration, usually 23 to 35%.
Oxygen concentration becomes, and the flow rate is adjusted by the flow rate controller 18 of the pipe 60, and the gas is supplied to the combustion type abatement device 11 as combustion supporting gas. The flow rate of the oxygen-enriched air amount extracted as the combustion-supporting gas source is adjusted by the valve 61 according to the required cold amount of the oxygen-enriched air amount branched to the expansion turbine 53, and the pipeline 5
The amount of oxygen-enriched air branched into 5 can be set by adjusting the valve 56 and the valve 62 provided in the conduit 54. Further, regarding the flow rate and oxygen concentration of the combustion-supporting gas, the dilution air amount is adjusted by the valve 63 provided in the pipe line 17 with respect to the oxygen-enriched air amount flowing into the oxygen concentration adjusting means 16 through the valve 62. Can be set by.

In this embodiment, as the dilution air for adjusting the oxygen concentration, a part of the raw material air after the impurities are removed by the purifier 36 is branched and the pressure is adjusted by the valve 63 before use. By this, the equipment related to the compressor including the filter and the aftercooler is limited to the raw material air compressor 33 to simplify the equipment and reduce the equipment cost and the maintenance cost. The air can also be used for dilution. At this time, the oxygen-enriched air, which is a by-product gas of the nitrogen production apparatus 12, is a dry gas from which water has been removed by the purifier 36, and therefore even when the compressed air mixed with the oxygen-enriched air is not dry air. The combustion-supporting gas in a somewhat dry state can be supplied to the combustion-type abatement device 11.

As described above, the oxygen-enriched air is supplied to the semiconductor manufacturing equipment having the semiconductor manufacturing equipment 10 using high-purity nitrogen, which is attached to the semiconductor manufacturing equipment 12. Or more, preferably 0.2
The oxygen-enriched air is used as a combustion-supporting gas for the combustion-type abatement system 11 so as to support the oxygen-enriched air that was conventionally released as waste gas into the atmosphere. It can be effectively used as gas. Furthermore, the flame temperature can be raised by using a gas having an oxygen concentration higher than that of air as the combustion supporting gas, and the PFCs that can be decomposed only at a high temperature can be surely treated.

By adjusting the oxygen concentration of the combustion-supporting gas by mixing the dilution air with the oxygen concentration adjusting means 16, even if the oxygen concentration in the oxygen-enriched air withdrawn from the nitrogen producing device 12 varies. Since the oxygen concentration of the combustion-supporting gas can be kept constant and the combustion conditions in the combustion-type abatement device 11 can be kept constant, a stable combustion flame can be obtained.
More effective detoxification treatment can be performed.

Furthermore, as shown in the present embodiment, by using a part of the raw material air that has passed through the purifier 36 as the dilution air, the combustion type abatement device 11 for combustion support containing almost no water or carbon dioxide. Since gas can be supplied, the flame temperature can be raised and the amount of harmful carbon monoxide generated can be greatly reduced.

FIG. 3 is a system diagram showing a second embodiment of the cryogenic separation type nitrogen producing apparatus 12. In the following description, the same components as those of the cryogenic separation type nitrogen manufacturing apparatus of the first embodiment shown in FIG. 2 are designated by the same reference numerals and detailed description thereof will be omitted.

In the present embodiment, the takeout position of the oxygen-enriched air, which is the combustion-supporting gas source, is in the middle of the heat exchanger 38, and the low-temperature oxygen-enriched air is withdrawn. That is, the total amount of the oxygen-enriched air that has flowed into the heat exchanger 38 from the pipe line 51 is fed to the pipe line 52 provided in the middle portion of the heat exchanger 38 by 0.1 MP.
After extracting at a or more, preferably 0.2 to 0.5 MPa, a part thereof is branched to the expansion turbine 53 for generating cold, and the rest is extracted from the pipe 71 to the oxygen concentration adjusting means 16 in a low temperature state. ing. Oxygen concentration adjusting means 16
The amount of oxygen-enriched air withdrawn into the chamber can be set by adjusting the valves 56 and 61 and the valve 72 of the conduit 71.

The oxygen concentration adjusting means 16 is provided with a pipe 73 for supplying diluted air and a pipe 74 for supplying oxygen, and the oxygen concentration adjusting means 1 is passed through a valve 72 of the pipe 71.
The oxygen-enriched air flowing into 6 is adjusted to a desired flow rate and a desired oxygen concentration by adjusting valves 75 and 76 provided in both conduits 73 and 74, respectively.
Drains to zero. At this time, by supplying high-concentration oxygen having an oxygen concentration of 95% or more from the oxygen supply conduit 74,
It is possible to make the oxygen concentration of the combustion-supporting gas supplied from the pipe 60 to the combustion-type detoxification device 11 higher than the oxygen concentration of the extracted oxygen-enriched air. The supply amount of the gas for use can be arbitrarily increased.

FIG. 4 is a system diagram showing a third embodiment of the nitrogen producing apparatus 12. In the present embodiment, the expansion turbine provided in both the embodiments is not provided, and the cold required for operating the apparatus is obtained by introducing liquefied nitrogen from the outside. Liquefied nitrogen as a cold source is supplied from the liquefied nitrogen storage tank 47 or the like to the upper part of the rectification column 31 via a pipe line 46. Note that it is also possible to introduce liquefied nitrogen using the conduit 45.

The oxygen-enriched liquefied air separated in the rectification column 31 is vaporized in the condenser 44 to become oxygen-enriched air of 0.1 MPa or more, preferably 0.2 to 0.5 MPa, and then the pipeline. After 50, the whole amount is introduced into the heat exchanger 38, where cold is recovered and led to the pipe 81. From the pipe 81, a pipe 82 for taking out the gas used as the regeneration gas of the purifier 36 and a pipe 83 for introducing the oxygen-enriched air serving as the combustion supporting gas source into the oxygen concentration adjusting means 16. And are branched, and valves 84 and 85 for adjusting the branching amount of the oxygen-enriched air are provided in both pipe lines 82 and 83, respectively. The oxygen-enriched air introduced through the pipe 83 and the diluted air whose flow rate is adjusted by the valve 86 and introduced through the pipe 17 are mixed by the oxygen concentration adjusting means 16, whereby the combustion-supporting gas having a predetermined oxygen concentration is produced. It is generated and supplied to the combustion-type abatement system 11 via the flow rate controller 18. As described above, by using liquefied nitrogen as a cold source, a large amount of oxygen-enriched air of 0.1 MPa or more can be obtained as compared with the above-mentioned both examples, and the supply amount of the combustion-supporting gas can be increased. You can

Next, a means for adjusting the oxygen concentration of the combustion-supporting gas to a desired concentration by mixing diluted air or oxygen with oxygen-enriched air will be described. Generally, the oxygen concentration of the oxygen-enriched air extracted as a by-product gas from the nitrogen manufacturing apparatus varies depending on the operating state of the nitrogen manufacturing apparatus, and usually fluctuates within the range of 25 to 45%. Therefore, in order to keep the oxygen concentration of the supplied combustion-supporting gas constant, it is necessary to control the amount of dilution air and the amount of oxygen mixed with the oxygen-enriched air according to the flow rate and oxygen concentration of the oxygen-enriched air. .

First, FIG. 5 is a system diagram showing a first embodiment of the oxygen concentration adjusting means 16. This oxygen concentration adjusting means 1
Reference numeral 6 denotes a pipe 103 by mixing the oxygen-enriched air introduced from the pipe 101 and the dilution air introduced from the pipe 102.
An example in which a combustion-supporting gas having a desired oxygen concentration is delivered is shown in FIG. The oxygen-enriched air conduit 101 is provided with a flow rate indicator controller (FIC) 104, an oxygen concentration meter (QI) 105, and a flow rate adjustment valve 106, and the diluted air conduit 10 is provided.
2 is provided with a flow rate indicating controller 107 and a flow rate adjusting valve 108. Further, the conduit 1 for delivering the combustion supporting gas
Also in 03, an oxygen concentration meter 109 and a flow rate control valve 110 are provided.

The flow rate of the oxygen-enriched air measured by the flow rate indicator controller 104, the oxygen concentration of the oxygen-enriched air measured by the oxygen concentration meter 105, and the oxygen concentration of the combustion-supporting gas measured by the oxygen concentration meter 109 are The concentration adjuster 111 calculates the required flow rate of the dilution air based on these measured values, and outputs the calculation result to the flow rate indicator controller 107. The flow rate indicator controller 107 is
The flow rate control valve 108 is controlled based on the current dilution air flow rate and the calculation result, and the flow rate of the dilution air is adjusted to a predetermined amount. As a result, the oxygen concentration of the combustion-supporting gas after mixing can be maintained at the desired oxygen concentration. Further, the flow rate of the combustion supporting gas can be adjusted by setting the flow rate of the oxygen-enriched air in the flow rate indicating controller 104.

FIG. 6 is a system diagram showing a second embodiment of the oxygen concentration adjusting means 16. The oxygen concentration adjusting means 16 mixes the oxygen-enriched air from the pipe 101, the diluted air from the pipe 102, and the oxygen gas from the pipe 112 to mix the pipe 1.
Reference numeral 03 shows an example in which a combustion-supporting gas having a desired oxygen concentration is delivered. As in the case of the above-described embodiment, a flow rate indicating controller 104, an oxygen concentration meter 105 and a flow rate adjusting valve 106 are provided in the oxygen-enriched air conduit 101, and a flow rate indicating controller 107 and a flow rate adjusting are provided in the diluting air conduit 102. The valve 108 is provided with an oxygen concentration meter 109 and a flow rate control valve 110 in the pipeline 103 for sending the combustion supporting gas, and a pipeline for oxygen gas to which high-concentration oxygen having an oxygen concentration of 95% or more is supplied. 1
12, a flow rate indicating controller 113 and a flow rate adjusting valve 114 are also provided.
Is provided.

Also in this embodiment, each flow rate indicating controller,
The measured value from each oxygen concentration meter is input to the concentration controller 111, respectively, and the signal from the concentration controller 111 causes the flow rate indicator controller 107 to control the flow rate control valve 108 and the flow rate indicator controller 113 to control the flow rate control valve 114, respectively. By controlling in the same manner as described above, the oxygen concentration of the combustion-supporting gas after mixing can be arbitrarily adjusted and supplied to a wide range of 23 to 90% according to the combustion conditions of the combustion-type abatement device 11. Becomes

In this way, by adding a system for adding and mixing oxygen gas to the oxygen-enriched air, the nitrogen production apparatus 12
It is also possible to cope with the case where a combustion supporting gas having an oxygen concentration higher than that of the oxygen-enriched air generated in the above is required. In this case, as compared with the case where the oxygen-enriched gas is simply obtained by mixing air and oxygen, the amount of oxygen gas added can be reduced, and the cost of oxygen generation equipment can be reduced. Further, even when the oxygen concentration required as the combustion supporting gas is lower than that of the oxygen-enriched air generated in the nitrogen production device, it is possible to deal with it by using the oxygen concentration adjusting means as shown in this embodiment. In addition, even when the nitrogen production apparatus 12 is stopped due to maintenance and inspection, it is possible to continuously supply the combustion-supporting gas having a predetermined oxygen concentration by mixing the dilution air and the oxygen gas.

When it is not necessary to strictly maintain the oxygen concentration of the combustion supporting gas, as shown in the system diagram of the third embodiment of the oxygen concentration adjusting means of FIG. Road 1
01 and the pipe 102 for dilution air are provided with valves 115 and 116, respectively, and connected, and the pipe 103 for the combustion-supporting gas after connection is connected.
Oxygen concentration meter for monitoring the oxygen concentration of combustion supporting gas 1
Even with a simple configuration in which only 17 is provided, the oxygen concentration of the combustion supporting gas can be maintained within a certain range.

In the above description, the gas used after the oxygen concentration of the oxygen-enriched air has been adjusted has been described as the combustion-supporting gas for the combustion-type abatement device 11. However, for other purposes, for example, combustion-supporting in a boiler. It can also be used as a gas for use. That is, in the semiconductor manufacturing process in the semiconductor manufacturing facility, there are many processes in which the constant temperature and constant humidity are maintained, and for example, equipment for obtaining a constant temperature and constant humidity for air conditioning in a clean room or the like, for maintaining pure water temperature, and utilities. Has become a target for cost reduction because its cost is considerable. In general, steam is supplied from a boiler as a heating source, but the heating furnace for the boiler usually performs heating with a heavy oil / air burner. Therefore, by replacing the air of the heavy oil / air burner with the combustion-supporting gas obtained as described above, it is possible to significantly increase the combustion efficiency of the heating furnace.

[0041]

EXAMPLES Example With the configuration shown in FIG. 2, the high-purity nitrogen generation rate is 100 m ³ / h.
60 m ³ / hr of oxygen-enriched air with an oxygen concentration of around 35% was extracted at 0.2 MPa from the cryogenic separation type nitrogen production device of r and mixed with it while adjusting the flow rate of diluted air consisting of the raw material air after production. A combustion supporting gas having an oxygen concentration of 30% was generated. About 18 m ³ / hr of this combustion-supporting gas is L
The combustion type abatement device using PG as a fuel was supplied so that the fuel-air ratio was 1 time the theoretical fuel-air ratio, and the abatement process of the exhaust gas discharged from the semiconductor manufacturing device was performed. At this time, the flame temperature in the combustion-type abatement device reached 1150 ° C., and the decomposition rate of CF ₄ which was the most difficult to decompose was about 90%. In addition, the concentration of carbon monoxide generated by the combustion type abatement system is 20p.
It was about pm.

Comparative Example In the same combustion type abatement system as in the example, a gas in which high-purity oxygen gas and compressed air were mixed to adjust the oxygen concentration to 30% was used as the combustion-supporting gas. As a result, the flame temperature was 1100 ° C due to the effect of moisture contained in the combustion-supporting gas.
The decomposition rate of CF ₄ decreased to about 70%.
Moreover, the carbon monoxide concentration increased to about 100 ppm.
In this case, it is necessary to install an air compressor for supplying compressed air and an oxygen supply facility for supplying high-purity oxygen gas.

[0043]

As described above, according to the semiconductor manufacturing equipment of the present invention, the semiconductor manufacturing equipment using high-purity nitrogen and the liquid crystal manufacturing equipment are provided, and the exhaust gas discharged from these equipment is removed. In a semiconductor manufacturing facility equipped with a combustion-type detoxification device that performs the above, the oxygen-enriched air obtained from the deep-separation-type nitrogen manufacturing device attached to the semiconductor manufacturing facility can be effectively used, and the combustion-type decontamination device can be used. It is possible to significantly reduce the cost of the combustion-supporting gas supplied to the harmful device. In addition, the oxygen-enriched air obtained from the nitrogen production device is
Since it does not contain impurities such as carbon dioxide and water, it can raise the flame temperature of the combustion type detoxification device, and can perform more effective combustion detoxification process, and carbon monoxide generated by combustion. The concentration can also be reduced.

[Brief description of drawings]

FIG. 1 is a schematic system diagram showing one example of a semiconductor manufacturing facility of the present invention.

FIG. 2 is a system diagram showing an example of a first embodiment of a deep-chill separation type nitrogen production device.

FIG. 3 is a system diagram showing a second form example of a deep-chill separation type nitrogen production apparatus.

FIG. 4 is a system diagram showing a third example of a deep-separation-type nitrogen production device.

FIG. 5 is a system diagram showing a first embodiment of the oxygen concentration adjusting means.

FIG. 6 is a system diagram showing a second embodiment of the oxygen concentration adjusting means.

FIG. 7 is a diagram showing a third example of the oxygen concentration adjusting means.

[Explanation of symbols]

10 ... Semiconductor manufacturing equipment, 11 ... Combustion type abatement equipment, 12 ...
Cryogenic separation type nitrogen production device, 16 ... Oxygen concentration adjusting means, 1
8 ... Flow controller, 19 ... Analyzer, 21 ... Scrubber, 3
1 ... Single rectification tower, 33 ... Raw material air compressor, 36 ... Purifier,
38 ... Heat exchanger, 44 ... Condenser, 47 ... Liquefied nitrogen storage tank,
49 ... Pressure reducing valve, 53 ... Expansion turbine, 104, 107,
113 ... Flow rate indicating controller, 105, 109 ... Oxygen concentration meter, 106, 108, 110, 114 ... Flow rate controlling valve, 1
11 ... Concentration controller

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F25J 3/04 101 F25J 3/04 101 (72) Inventor Gan Shibata 1-16- Nishishinbashi, Minato-ku, Tokyo 7 Japan Oxygen Stock Company (72) Inventor Shinichiro Yamamoto 1-16-7 Nishishinbashi, Minato-ku, Tokyo Japan Oxygen Stock Company (72) Inventor Shuyasu Tomita 1-16-7 Nishishinbashi, Minato-ku, Tokyo Japan Oxygen Stock Company (72) Inventor Shuichi Koseki 1-16-7 Nishishinbashi, Minato-ku, Tokyo Nippon Oxygen Stock Company (72) Inventor Mangaku Daiki 1-16-7 Nishishinbashi, Minato-ku, Tokyo Nippon Oxygen Stock company (72) Inventor Hiroyuki Ono 1-16-7 Nishishimbashi, Minato-ku, Tokyo Japan Oxygen Company F-term (reference) 3K062 AB01 AC19 BA02 CB08 DA07 DB05 3K078 AA04 BA20 BA26 BA27 BA28 BA29 CA21 4D047 AA08 AB01 AB 02 CA09 DA03 DA14 DA17

Claims (7)

[Claims] 1. A semiconductor manufacturing apparatus that uses high-purity nitrogen gas, and a combustion-type abatement apparatus that burns and removes exhaust gas discharged from the semiconductor manufacturing apparatus with a combustion flame that uses oxygen-enriched air as a combustion-supporting gas. And a deep-separation-type nitrogen production device for producing high-purity nitrogen gas for use in the semiconductor production device and for producing oxygen-enriched air for use in the combustion-type detoxification device. Semiconductor manufacturing equipment. 2. The oxygen concentration of oxygen-enriched air supplied from the deep-separation-type nitrogen producing device to the combustion-type abatement device is adjusted between the deep-separation-type nitrogen producing device and the combustion-type abatement device. The semiconductor manufacturing facility according to claim 1, further comprising: 3. A path for supplying a part of the oxygen-enriched air after the oxygen concentration adjustment as a combustion supporting gas for the boiler is branched downstream of the means for adjusting the oxygen concentration of the oxygen-enriched air. The semiconductor manufacturing facility according to claim 1, wherein: 4. The cryogenic separation type nitrogen producing apparatus comprises a raw material air compressor for compressing the raw material air, a purifier for purifying the compressed raw material air, and a raw material air after the purification such as a product gas. A heat exchanger for cooling by exchanging heat with the return gas, a rectification tower for separating the cooled raw material air into nitrogen gas and oxygen-enriched liquefied air by liquefaction rectification, the nitrogen gas and the oxygen enrichment A condenser that heat-exchanges with liquefied air to condense nitrogen gas and vaporizes oxygen-enriched liquefied air, and an expansion turbine that generates cold are provided, and the raw material air is the raw material air compressor, the purifier, and A route through which the nitrogen gas is introduced into the rectification column through the heat exchanger, a route through which the nitrogen gas is discharged from the rectification column and reaches the normal temperature through the heat exchanger, and is taken out as product nitrogen, and the oxygen-enriched liquefaction. Air is introduced from the rectification tower In the path of the product oxygen-enriched gas and the path taken out as a product oxygen-enriched gas after being discharged and vaporized in the condenser to become oxygen-enriched air, passing through the heat exchanger and reaching room temperature, A path branched from the middle part of the heat exchanger to introduce a part of the oxygen-enriched air into the expansion turbine, and a path through which the oxygen-enriched air exiting the expansion turbine becomes the room temperature through the heat exchange again and is taken out as exhaust gas. The semiconductor manufacturing equipment according to claim 1, further comprising: 5. The product oxygen-enriched gas path is connected to a path of purified air in the path of the raw material air and branched from the downstream side of the purifier, and the product after being mixed in both paths. The semiconductor manufacturing facility according to claim 4, further comprising means for adjusting the oxygen concentration of the oxygen-enriched gas. 6. The path of the product oxygen-enriched gas, which is led out from the heat exchanger, is replaced with a path of passing through the heat exchanger to reach room temperature and taken out as a product oxygen-enriched gas. The low-temperature oxygen-enriched gas branched from the middle part to the expansion turbine and branched before the expansion turbine is introduced is used as a product oxygen-enriched gas, and oxygen gas and / or compressed air is mixed in the path. 5. The semiconductor manufacturing facility according to claim 4, further comprising means for connecting the passages and adjusting the oxygen concentration of the product oxygen-enriched gas after mixing in each of the passages. 7. An outlet for introducing the liquefied nitrogen into the upper part of the rectification column in place of the expansion turbine and the path for introducing the expansion turbine and the path for the exhaust gas, and the outlet for the path for the product oxygen-enriched gas. Of the product oxygen-enriched gas branched from the section, a route for supplying compressed air and / or oxygen gas, a route connecting the route with the branched route, and a route of the product after mixing to each route. 5. The semiconductor manufacturing facility according to claim 4, further comprising means for adjusting the oxygen concentration of the oxygen-enriched gas.