JP3866808B2 - Semiconductor manufacturing process exhaust gas abatement equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exhaust gas discharged in a semiconductor manufacturing process containing a combustible gas, a toxic gas, or a gas component that needs to be removed or reduced in concentration when discharged into the atmosphere from the viewpoint of environmental protection. The present invention relates to an exhaust gas abatement device for semiconductor manufacturing process for combustion and decomposition.
[0002]
[Prior art]
Exhaust gas discharged in various processes in the manufacture of semi-conductor contains harmful components SiH ₄ or the like as a semiconductor material, it is discharged into the atmosphere the exhaust gas as it contains such a component I can't. Therefore, various exhaust gas abatement devices have been proposed that exhaust and decompose harmful components in semiconductor manufacturing process exhaust gases when exhausting such exhaust gases containing harmful components into the atmosphere.
[0003]
By the way, conventionally, SiH ₄ was mainly treated as a harmful component in the exhaust gas discharged in the semiconductor manufacturing process by the combustion type exhaust gas abatement apparatus. A type that can process a large amount of exhaust gas discharged from different routes at the same time or change the time cycle to the same route due to the increase in size, the multi-chamber with the spread of single-wafer devices, the complexity of the manufacturing process, etc. It has become necessary to treat different exhaust gases with the same abatement device, and an exhaust gas abatement device with high combustion efficiency has become necessary.
[0004]
In view of such a situation, in recent years, an exhaust gas abatement device provided with a plurality of combustion burners in one combustion cylinder and supplying exhaust gas discharged through different paths to each burner for processing, There is used an exhaust gas abatement apparatus in which a large-capacity combustion burner is provided in a combustion cylinder, and a plurality of exhaust gases discharged through different paths are supplied to the burner for processing.
[0005]
[Problems to be solved by the invention]
However, in an apparatus in which a plurality of combustion burners are provided in one combustion cylinder, it is necessary to redesign the size of the combustion cylinder each time it is necessary to increase the number of combustion burners due to an increase in the exhaust gas supply system, etc. In addition, the arrangement of the combustion burner in the combustion cylinder and the flow of the air introduced into the combustion cylinder have a great influence on the combustion efficiency, and there is a problem that adjustment before installation takes a lot of time. Further, in order to provide a plurality of combustion burners in one combustion cylinder, there is a problem that a piping system such as an exhaust gas supply pipe connected to each combustion burner becomes complicated and the assembly work becomes complicated.
[0006]
On the other hand, in the case of a device provided with a large-capacity combustion burner in one combustion cylinder, it is possible to easily cope with an increase in the exhaust gas supply system, etc., compared to a device provided with a plurality of combustion burners. However, since the amount and type of exhaust gas treated by the exhaust gas abatement device is not always constant, in the case of an abatement device equipped with a large-capacity combustion burner, even if a large amount of exhaust gas can be treated efficiently, When the processing amount is small, the processing efficiency for the unit fuel amount may be deteriorated. In addition, when different exhaust gases are introduced into one combustion burner and processed, if combustible gas and combustion-supporting gas are mixed and supplied to the combustion burner, there is a risk of explosion depending on the combination and concentration of both. . In addition, in the case of an abatement device that supplies exhaust gas from a plurality of exhaust gas supply systems to a single combustion burner, if any abnormality occurs in one exhaust gas supply system, all exhaust gases supplied from other exhaust gas supply systems are processed. There was also a problem that had to be stopped.
[0007]
In addition, if the exhaust gas contains SiH ₄ , the combustion product SiO ₂ powder is likely to accumulate near the exhaust port of the combustion cylinder, but the conventional apparatus accumulates a certain amount or more of SiO ₂ powder. Then, not only does it fall on the combustion burner part and adversely affect the combustion efficiency, but there is a risk of extinguishing the flame in severe cases. In order to solve such a problem, it is also considered to provide a combustion burner downward. In this case, since the exhaust gas burned in the combustion cylinder is discharged from the exhaust port below the combustion cylinder, There is a problem that it is necessary to design an exhaust duct having a structure in which the treated exhaust gas discharged to the lower side is discharged upward again, and a large space is required to install the exhaust duct.
[0008]
Furthermore, the combustion type exhaust gas abatement system can quickly stop exhaust gas from being supplied to the combustion cylinder when an abnormality occurs, such as the exhaust fan being stopped, the combustion flame extinguishing, or the exhaust line being blocked from the combustion cylinder. An emergency discharge pipe for discharging to the outside is provided in the middle of the exhaust gas supply pipe for supplying exhaust gas to the combustion cylinder. However, in the conventional apparatus, as shown in FIG. 3, the exhaust gas supply pipe 3 for supplying exhaust gas to the combustion burner 2 provided in the combustion cylinder 1 is bent at a right angle and connected to the combustion burner 2. The emergency discharge pipe 4 is provided so as to be in the extending direction of the supply pipe 3. For this reason, normally, the exhaust gas is supplied to the combustion burner 2 through the bent exhaust gas supply pipe 3, and the exhaust gas is liable to stay. In addition, when the exhaust gas is discharged from the emergency discharge pipe 4 to the outside in an emergency, the inert gas supply pipe 5 that supplies an inert gas for diluting the exhaust gas emits the exhaust gas from the emergency discharge pipe 4. In addition, it has a structure in which inert gas is supplied from the direction that goes straight, so it is difficult to quickly discharge exhaust gas in an emergency, and the flow of exhaust gas may be hindered by the pressure of the inert gas .
[0009]
An object of the present invention is to provide an exhaust gas abatement apparatus that can solve the various problems of the conventional exhaust gas abatement apparatus.
[0010]
[Means for Solving the Problems]
That is, the semiconductor manufacturing process exhaust gas abatement apparatus of the present invention is an exhaust gas abatement apparatus for treating exhaust gas by combustion of fuel gas. The exhaust gas abatement apparatus is provided to surround a combustion burner and a combustion portion of the combustion burner, and to take in air at the bottom. Combustion is performed so that the air ratio to the theoretical air amount of fuel is 0.6 to 0.8 in the primary region where the air supply amount from the hole is adjusted and the harmful components in the exhaust gas are burned together with the combustion of the fuel gas. A plurality of combustion cylinders having an inner cylinder having a plurality of air introduction holes and an outside air intake are provided according to the number of exhaust gas exhaust systems discharged in the semiconductor manufacturing process, and the exhaust ports of each combustion cylinder Is connected to an exhaust duct.
[0011]
In the apparatus of the present invention, when exhaust gas containing SiH ₄ is treated by connecting each combustion cylinder laterally to the collecting duct so that the combustion cylinder is horizontal or the exhaust port of the combustion cylinder faces downward from the horizontal. as possible out to prevent combustion failure according SiO ₂ powder occurring. The combustion burner of the combustion cylinder, an emergency discharge pipe for discharging exhaust gas to the outside in an emergency Oite in the middle of each of the exhaust gas supply pipe for supplying the exhaust gas discharged in a semiconductor manufacturing process, the exhaust gas supply pipe For an ordinary combustion burner by providing an inert gas introduction nozzle for supplying an inert gas for dilution of exhaust gas in the direction of exhaust gas discharge from the emergency discharge pipe. The exhaust gas can be supplied smoothly, and the exhaust gas can be discharged smoothly and quickly in an emergency.
[0012]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows an embodiment of the exhaust gas abatement apparatus of the present invention. In FIG. 1, 1 is a combustion cylinder, and each combustion cylinder 1 is provided with a combustion burner 2 as shown in FIG. In the figure, 3 is an exhaust gas supply pipe, 4 is an emergency discharge pipe, 5 is an inert gas supply pipe, and 6 is an exhaust duct. In the exhaust gas abatement apparatus of the present invention, as shown in FIG. 1, the exhaust port 7 of each combustion cylinder 1 is connected to the exhaust duct 6 and the combustion burner 2 in each combustion cylinder 1 is supplied from different systems. The exhaust gas is configured to be supplied by the exhaust gas supply pipe 3.
[0013]
One of the features of the exhaust gas abatement apparatus of the present invention is that a plurality of combustion cylinders 1 provided with a combustion burner 2 are provided according to the number of exhaust gas supply systems. It is to be connected to the exhaust duct 6 in the horizontal direction. By making the combustion cylinder 1 sideways, even if SiH ₄ is contained in the exhaust gas, a combustion failure of the combustion burner 2 due to the SiO ₂ powder that is the combustion product hardly occurs. The combustion cylinder 1 may be connected horizontally to the collective duct 6, but if the exhaust port 7 is connected sideways with a slight downward inclination, the combustion failure of the combustion burner 2 due to SiO ₂ powder is more effectively prevented. be able to. When the combustion cylinder 1 is inclined, the inclination angle α is preferably set to 10 ° or less, but is preferably set to around 5 ° in consideration of the layout of the entire apparatus. When connecting to the exhaust collective duct 6 with the combustion cylinder 1 facing sideways, the exhaust collective duct 6 is provided vertically or obliquely upward so as to exhaust upward from below.
[0014]
Although not particularly illustrated, the combustion burner 2 inside the combustion cylinder 1 may be provided with a free rotating blade having a rotation axis along the exhaust gas discharge direction and rotating by the exhaust gas flow. By providing such free rotating blades, it is possible to prevent adhesion and accumulation of SiO ₂ powder, which is a combustion product of SiH ₄ contained in the exhaust gas, near the exhaust port 7.
[0015]
In the exhaust gas abatement apparatus of the present invention, an inner cylinder 8 surrounding the combustion part of the combustion burner 2 is provided in the combustion cylinder 1 as shown in FIG . According to the studies by the present inventors, in order to efficiently burn and decompose harmful components in exhaust gas, a primary region (in the figure) where appropriate air is supplied to burn the harmful components in exhaust gas together with the combustion of fuel gas. , A region marked with a), CO, generated by combustion, a secondary region that supplies a small amount of air in stages to further burn H ₂ (region marked with b in the figure), and It is necessary to reduce the temperature of the exhaust gas that has been subjected to combustion treatment by supplying a large amount of air, and to appropriately perform each step in the dilution region (region marked with c in the figure) for diluting the exhaust gas. found.
[0016]
The fuel gas supplied to the combustion burner 2 is premixed with air. However, in order to efficiently burn harmful components in the exhaust gas, it is necessary to supply outside air from the outside of the flame. In the conventional exhaust gas abatement apparatus of this type, there is nothing equivalent to the inner cylinder 8, so the outside air introduced into the combustion cylinder is directly supplied to the combustion burner. However, if the outside air introduced into the combustion cylinder is supplied to the combustion burner as it is, there is a risk that excessive air will be supplied and the temperature in the vicinity of the combustion burner may be lowered. By providing an inner cylinder 8 that surrounds the two combustion parts, providing an air intake hole 9 at the bottom of the inner cylinder 8, and adjusting the air supply amount in the primary region a by adjusting the hole diameter of the air intake hole 9 The primary region a can be adjusted so that optimum combustion can be performed.
[0017]
The exhaust gas that has been subjected to the combustion treatment in the primary region a contains CO, H _{2, and the} like, but if a large amount of air is supplied in the secondary region b, complete combustion of these substances is hindered. Therefore, in the secondary region b, the air intake holes 10 are provided in the inner cylinder 8, and the amount of air supplied to the secondary region b is adjusted by adjusting the number of the air intake holes 10, the hole interval, and the hole diameter. Usually, in the primary region, combustion is performed so that the air ratio to the theoretical air amount of fuel is 0.6 to 0.8 from the combustion efficiency, combustion exhaust gas, and the like. Therefore, in the secondary region b, the remaining air amount necessary for complete combustion is introduced, the required air hole area is calculated from the average air flow velocity in the cylinder, and the hole diameter is determined. The position of the air hole in the secondary region b is determined empirically from the in-cylinder flow velocity and the like. However, at this time, the air holes are provided at opposite positions with the same cross-sectional area so as to promote stirring of the inflowing air. The number of air holes is preferably 12 to 36, and particularly preferably 24.
[0018]
In order to quickly reduce the temperature of the exhaust gas after passing through the secondary region b, it is necessary to introduce a large amount of dilution air into the dilution region c. Therefore, an intake hole 11 having a larger opening area than the air intake hole 10 in the secondary region b is provided in the dilution region c portion of the inner cylinder 8. The amount of dilution air introduced into the dilution region c is adjusted by the number of the air intake holes 11, the hole interval, and the hole diameter. The amount of air flowing into the dilution region c is an amount obtained by subtracting the amount of air introduced into the inner cylinder b in the primary region a and the secondary region b from the outside air amount introduced into the combustion tube. Therefore, the most important point in the dilution region c is that the air intake hole in this region is more than the cross-sectional area of the exhaust port 7 of the combustion cylinder 1 so that the air flowing into the primary region a and the secondary region b is not affected. It is necessary to increase the total area. Further, the number thereof is 4 to 8 in the same flat cross section of the dilution region c, and in other flat cross sections, the air holes are provided in a staggered manner so that the vertical positions of the air holes do not overlap to promote air mixing in the inner cylinder 8. It is preferable. The diameter of the air holes in the dilution region c is determined from the total area of the holes, the arrangement, the installation space, and the like. In addition, outside air can be taken into the combustion cylinder 1 from the outside air inlet 12, and a part of the outside air introduced into the combustion cylinder 1 is used for combustion and the rest is used for exhaust gas exhaust. Is done. The amount of outside air taken in from the outside air inlet 12 is adjusted by changing the degree of opening of the damper 13.
[0019]
In the apparatus of the present invention, it is preferable that the exhaust gas supply pipes 3 for supplying exhaust gas to the combustion burners 2 of the respective combustion cylinders 1 are connected to the combustion burners 2 in a straight manner. On the other hand, in the middle of each exhaust gas supply pipe 3, an emergency release pipe 4 for releasing the exhaust gas to the outside in an emergency is provided to be branched in a T shape with respect to the exhaust gas supply pipe 3. It is preferable to provide an inert gas introduction nozzle 14 for supplying an inert gas for dilution of exhaust gas supplied from the inert gas supply pipe 5 toward the exhaust gas discharge direction. When the exhaust gas supply pipe 3, the emergency discharge pipe 4, and the inert gas introduction nozzle 14 are arranged in this way, the exhaust gas is smoothly supplied without stagnation in the direction of arrow A during normal time (when the exhaust gas is burned by the combustion burner 2). . On the other hand, when an abnormality or the like occurs during combustion, the valve 15 of the emergency discharge pipe 4 is opened and the inert gas is supplied from the inert gas introduction nozzle 14 so that the exhaust gas passes through the emergency discharge pipe 4. After that, it is discharged smoothly and quickly to the outside (arrow B).
[0020]
As the inert gas introduction nozzle 14, a supersonic nozzle capable of introducing an inert gas at a flow velocity higher than the sonic velocity in the nozzle portion is preferable. When an inert gas is introduced from a supersonic nozzle, the static pressure decreases with an increase in gas dynamic pressure in the vicinity of the nozzle tip, so the inert gas absorbs the gas present near the nozzle tip in the exhaust gas supply pipe 3. Thus, the effect of entrainment is obtained, and there is an effect that it is possible to prevent the stagnation of the exhaust gas when the exhaust gas is discharged from the emergency discharge pipe 4 in an emergency. As the supersonic nozzle, a nozzle having a Laval tube structure is preferable, but the structure is not particularly limited as long as the flow velocity in the nozzle portion can be made higher than the sound velocity.
[0021]
The exhaust gas targeted by the present invention is an exhaust gas containing a combustible component or a toxic component, or an exhaust gas containing a component that needs to be removed or reduced in concentration when discharged into the atmosphere from the viewpoint of environmental protection. For example, a gas containing SiH ₄ , SiH ₂ Cl ₂ , GeH ₄ , B ₂ H ₆ , AsH ₃ , PH ₃ , NF ₃ , C ₂ F _6, etc. discharged in various processes when manufacturing a semiconductor Is mentioned.
[0022]
The fuel gas supplied to the combustion burner 2 is mainly hydrogen, methane, propane, butane, ethylene, natural gas, or a mixed gas thereof, and air or oxygen-enriched air as necessary. Or the like as a combustion gas is used.
[0023]
[Action]
Abatement device of the present invention has a plurality of combustion cylinder 1 provided with a burner 2, depending on the increase in the number of discharge lines of the flue gas, is configured to increase the number of the combustion cylinder 1. When the exhaust gas system integration is increased, by adding the combustion cylinder 1 provided with a burner 2, it does not have to include the combustion burner of a large capacity such as may correspond to the increase in the exhaust gas system, exhaust system It can respond to the increase of the pressure.
[0024]
【The invention's effect】
Semiconductor manufacturing process flue gas abatement device of the present invention, a combustion cylinder having a combustion burner therein, a plurality provided according to the number of supply system of exhaust gas discharged in a semiconductor manufacturing process, when the exhaust gas supply system has increased Is configured to add a combustion cylinder for burning the exhaust gas discharged from the newly increased system, so that the exhaust gas discharged from a plurality of exhaust gas supply systems is burned in one combustion cylinder Therefore, it is easy to cope with an increase in the exhaust gas system as compared with an apparatus having a plurality of combustion burners. In addition, because the exhaust gas is burned in a separate combustion cylinder for each exhaust gas system, the amount of outside air required to burn and discharge the exhaust gas can be adjusted to the optimum amount according to the type of exhaust gas. It becomes possible. Furthermore, compared to a device that provides a large-capacity combustion burner in a single combustion cylinder and treats all exhaust gases at once with this combustion burner, efficient processing is possible even when the exhaust gas treatment amount is small. is there. In addition, even if a failure occurs in the combustion burner in the combustion cylinder that processes the exhaust gas of any system, the exhaust gas processing of other systems is not affected at all, and the normal processing can be performed. Has an effect. In addition, air is introduced into the combustion cylinder so that combustion is performed such that the air ratio to the theoretical air amount of fuel is 0.6 to 0.8 in the primary region by adjusting the air supply amount from the air intake hole at the bottom. By providing the inner cylinder provided with a plurality of holes so as to surround the combustion part of the combustion burner, the exhaust gas combustion treatment can be performed more effectively.
[0025]
Even if SiH ₄ or the like is contained in the exhaust gas, the combustion cylinder is connected horizontally to the collecting duct so that the combustion cylinder is horizontal or the exhaust port of the combustion cylinder faces downward from the horizontal. There is no fear that the combustion of the combustion burner is hindered by the generated SiO ₂ powder, and the exhaust gas combustion treatment can be performed efficiently .
[0026]
Furthermore, an emergency discharge pipe for releasing the exhaust gas to the outside in an emergency is provided in the middle of the exhaust gas supply pipe so as to be branched in a T shape with respect to the exhaust gas supply pipe, and in the direction of exhaust gas discharge from the emergency discharge pipe By providing an inert gas introduction nozzle that supplies an inert gas for dilution of exhaust gas toward the exhaust gas, the exhaust gas supplied to the combustion burner can be smoothly and smoothly retained in normal times, and in an emergency, the exhaust gas can be smoothly and quickly discharged by the inert gas. It has an effect that it can be released to the outside.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an outline of an example of an exhaust gas abatement apparatus of the present invention.
FIG. 2 is a schematic longitudinal sectional view showing a configuration in a combustion cylinder in the exhaust gas abatement apparatus of the present invention.
FIG. 3 is a schematic diagram showing an outline of a configuration of a conventional exhaust gas abatement apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Combustion cylinder 2 Combustion burner 3 Exhaust gas supply pipe 4 Emergency discharge pipe 6 Exhaust collective duct 7 Exhaust port 8 Inner cylinder 12 Outside air intake port 14 Inert gas introduction nozzle

Claims (5)

In an exhaust gas abatement apparatus for treating exhaust gas by combustion of fuel gas, a combustion burner and a combustion portion of the combustion burner are provided surrounding the combustion burner, and an air supply amount from a bottom air intake hole is adjusted so that An inner cylinder having a plurality of air introduction holes for causing combustion so that an air ratio with respect to the theoretical air amount of fuel is 0.6 to 0.8 in a primary region in which harmful components in exhaust gas are burned together with combustion; A plurality of combustion cylinders having intakes are provided in accordance with the number of exhaust gas exhaust systems discharged in the semiconductor manufacturing process, and the exhaust ports of the respective combustion cylinders are connected to exhaust collective ducts. Semiconductor manufacturing process exhaust gas abatement equipment. 2. An exhaust gas abatement apparatus for a semiconductor manufacturing process according to claim 1, wherein each combustion cylinder is connected laterally to the collecting duct so that the combustion cylinder is horizontal or an exhaust port of the combustion cylinder faces downward from the horizontal. . The semiconductor manufacturing process exhaust gas abatement apparatus according to claim 2, wherein the combustion cylinder is connected to the collecting duct so that the inclination of the combustion cylinder is 10 ° or less. A combustion burner of the combustion cylinder, Oite in the middle of each of the exhaust gas supply pipe for supplying the exhaust gas discharged in a semiconductor manufacturing process, an emergency discharge pipe for discharging exhaust gas to the outside in an emergency, the exhaust gas supply pipe And an inert gas introduction nozzle for supplying an inert gas for dilution of exhaust gas in the direction of exhaust gas discharge from the emergency discharge pipe. The semiconductor manufacturing process exhaust gas abatement apparatus according to any one of to 3 . 5. The semiconductor manufacturing process exhaust gas abatement apparatus according to claim 4 , wherein the inert gas introduction nozzle is a supersonic nozzle that introduces the inert gas at a flow velocity equal to or higher than the sonic velocity in the nozzle portion.

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