JP3237651B2 - Equipment for treating fluorine-containing organic halogen compounds - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst-based treatment apparatus for fluorine-containing organic halogen compounds contained in exhaust gas (hereinafter simply referred to as a treatment apparatus).

[0002]

_2. Description of the Related Art In recent years, with increasing interest in global environmental problems, measures have been required to suppress the emission of greenhouse gases such as CO ₂ and fluorine-containing organic halogen compounds which cause global warming. .

[0003] Fluorine-containing organic halogen compounds are harmless to the human body, are not explosive, are stable, and are easy to handle. Therefore, they are used in large quantities in the production process of electronic parts such as semiconductors and liquid crystals (hereinafter referred to as semiconductor production process). . In the dry etching process, perfluorocarbons such as CF ₄ (PF
C), SF ₆ , and a hydrofluorocarbon (HFC) such as CHF _{3 as} an alternative Freon is used as an etching gas. In the CVD process, C ₂ F ₆ is used as a cleaning gas for removing deposits inside the apparatus after film formation.

A fluorine-containing organic halogen compound gas is ionized by high-voltage plasma discharge after being introduced into an etching or CVD apparatus, and performs etching and cleaning of a wafer in a state of active radicals. However, the amount of gas consumed in etching and cleaning is only a few to several tens vol% of the supply amount, and the rest is discharged out of the system without reacting.

[0005] Fluorine-containing organic halogen compound gas emits a smaller amount of gas than CO ₂ , which is strongly required to be reduced, but has a long service life, and therefore has a high global warming potential. Therefore, emission control in the near future is considered to be inevitable. In this case, it is important to decompose the fluorine-containing organic halogen compound with respect to the exhaust gas from a semiconductor manufacturing plant, which accounts for the majority of the current release of the fluorine-containing organic halogen compound.

[0006] As a conventional decomposition technique for PFC or the like, a chemical method, a combustion method and a catalytic method have been put into practical use. But,
The chemical method requires frequent replacement of special chemicals, requires high operating costs, and has a practical device scale of about 3 to 5 m in installation area.
² and big. In addition, the combustion method thermally decomposes the fluorine-containing organic halogen compound in a flame of about 1,000 ° C. or more, so that a large amount of heat energy is required and not only goes against the prevention of global warming, but also NOx and a large amount There is also the generation of CO ₂ . In addition, PFC and the like in a semiconductor manufacturing process are diluted with an inert N ₂ gas and discharged, and therefore have a high misfire potential and a great safety problem. Furthermore, the scale of the apparatus is large, and the installation area is about 0.7 to ⁵ m ² . Since a semiconductor manufacturing plant is a clean room, there is a large space restriction, and it is not easy to secure a space particularly when newly installing a processing apparatus in an existing factory.

On the other hand, as a catalyst system, CFC (chlorofluorocarbon) or HCFC having ozone depleting action is used.
(Hydrochlorofluorocarbon)
A catalytic decomposition treatment that starts decomposition at about 400 ° C. has been put to practical use. Since CFCs and HFCs contain chlorine having a large atomic radius in the composition, the molecular structure bonded to fluorine or hydrogen having a small atomic radius becomes distorted, and thus decomposition at a relatively low temperature becomes possible.

Furthermore, the present inventors have found that the decomposition temperature is about 70.
We have successfully developed an alumina-based catalyst that can also be used for decomposition of CF _{4 and the} like at 0 ° C, and filed an application earlier (Japanese Patent Application No. 9-4349,
Japanese Patent Application No. 9-163717).

[0009]

The above-mentioned catalyst system has a long service life of 1,000 to 2,000 hours, so that it consumes a small amount of energy, and has a relatively low temperature and low heating energy. It is.

FIG. 2 shows a main structure of a conventional apparatus for treating a fluorine-containing organic halogen compound by a catalytic system. A main part of an apparatus for treating exhaust gas from a semiconductor manufacturing process is a front spray 1 for removing impurities such as Si ₄ contained in the exhaust gas of the manufacturing process by reacting with water or an alkaline solution,
The exhaust gas from which impurities have been removed is mixed with water or air and heated by a heater 8 to a reaction temperature, a heater 2 containing a catalyst 9 for decomposing the heated mixed gas, and a high-temperature decomposed gas is cooled. The cooling device 4 is constituted by a cooling device 4.

When the catalyst is replaced with this structure, once
The bolt connecting the upper flange 131 of the outer tube 31 of the reactor 3 to the lower flange 121 of the outer tube 21 of the heater 2 is removed, and the catalyst 9 is taken out from the upper portion of the reactor 3 from which the heater 2 has been removed. However, when the heater 2 is the heater 9 or the heat insulating material 2
0 and is located at the top of the reactor 3 so that it is required to work at a high place. In addition, when the processing apparatus is installed in a clean room, it is necessary to prevent generation of dust, and it is necessary to take out the reactor 3 outside the clean room. .

If the heater 2 and the reactor 3 are not sufficiently cooled before being replaced, there is a risk that the operator may be burned, which requires a long time for maintenance. By the way, catalyst 7
It took about one day to cool from 00 ° C. to 200 ° C., and during that time, there was a problem that the maintainability of the processing equipment was poor, such as the inability to operate a full-time 24-hour semiconductor manufacturing equipment.

Further, when used in a clean room, it is required to have a structure in which dust is not generated from the processing apparatus as much as possible. Therefore, the heater 2 and the reactor 3 are formed in a double tube structure and connected by flanges as shown in FIG. ing. In this structure, the heater 2
In order to hold the electric heater and the heat insulating material in the inner tube 22, the heat of the inner tube 22 in contact with the gas heated to the reaction temperature is radiated to the atmosphere via the flange 122. That is, there is a problem that heat loss is increased in structure.

On the other hand, there are also problems regarding the structure of the front spray and the heat resistance thereof in the conventional processing apparatus. In the pre-spray 1, SiF ₄ and water react with each other.

[0015]

## STR1 ## SiF ₄ + 2H ₂ O ⇒ SiO ₂ + 4HF That is, there is a problem that SiO ₂ , which is a solid substance, precipitates and adheres and deposits on the inner wall of the pipe 12 to cause blockage, requiring maintenance. .

In addition, since the pre-spray generates hydrofluoric acid which is highly corrosive by the reaction of the chemical formula 1, a metal material cannot be used, and a resin material such as polyvinyl chloride having corrosion resistance is used. However, when the processing apparatus is stopped, hot air having a high temperature of 100 ° C. or more may flow backward from the downstream heater to the front spray, and there is a problem that PVC having low heat resistance is thermally deformed and damaged.

In view of the problems of the prior art, a first object of the present invention is to convert a fluorine-containing organic halogen compound, which is one of the gases causing global warming, contained in an exhaust gas from a semiconductor manufacturing plant or the like, into a catalytic system. Accordingly, it is an object of the present invention to provide a processing apparatus which can be disassembled with high efficiency and has excellent maintainability.

A second object of the present invention is to provide a processing apparatus which can solve the problem of the front spray in the above processing apparatus and can prevent blockage and thermal deformation of a resin material having low heat resistance. .

[0019]

To achieve the above object, according to the present invention, there is provided the water are mixed, a heater for heating the gas to be treated to a Jo Tokoro reaction temperatures including fluorine-containing organohalogen compound, catalyst <br The medium contained therein and contained in the heated gas to be treated.
Decomposing reactor fluorine-containing organic halogen compounds, the reaction
Equipped with a cooler that cools the decomposition gas discharged from the reactor ,
The heater is attached to the reactor and the heater
The cooler located below can be removed to the reactor
Mounted on, characterized in that the catalyst is configured to be replaced from below the reactor.

[0020] As a structure in which the catalyst can be exchanged from below the reactor , preferably, the lower part of the reactor and the catalyst cartridge filled with the catalyst are detachable. Further, the heater and the reactor are constituted by a double tube, and at least an outer tube is integrated.

According to this, since the catalyst can be replaced by removing the cartridge from the lower part of the reactor, the replacement can be performed at a low place away from the heater, thereby facilitating the operation. In addition, since the cartridge is configured to be filled with the granular catalyst and is detachable at the lower part of the heater, the catalyst can be safely and easily taken out and can be replaced in a clean room. Also,
As it becomes possible to exchange at high temperature by using tools, etc.,
The work period can be greatly reduced, and the maintainability can be significantly improved.

Further, since the heater and the reactor are integrally formed, the heat dissipation from the flange joint as in the prior art is eliminated, so that the thermal efficiency is improved and the operating cost can be reduced.

Further, the structure of the front spray is improved,
Since the blockage of the inlet pipe and the backflow from the heater are prevented, failure of the front spray can be greatly reduced.

[0024]

Embodiments of the present invention will be described below in detail with reference to the drawings. Throughout the drawings, the same components are denoted by the same reference numerals.

FIG. 3 shows a schematic configuration of an exhaust gas treatment apparatus in a semiconductor manufacturing process to which the present invention is applied. Exhaust gas containing CF ₄ from an etching device (not shown) is sprayed with SiF
After removing ₄ and solid content (SiO ₂ ), the mixture is mixed with water necessary for the reaction and introduced into the heater 2. In heater 2,
The etching exhaust gas is heated to about 700 ° C. The heated mixed gas is, for example, an alumina (Al ₂ O ₃ ) -based catalyst 9.
There performed reaction of 2 reactor 3 filled, the CF ₄ C
Decomposes into O ₂ and HF.

[0026]

The high-temperature decomposed gas after decomposition of CF ₄ + 2H ₂ O ⇒ CO ₂ + 4HF is cooled by a sprayer in a cooler 4 and a part of HF is removed, and then guided to a packed tower 5.
HF is removed. The decomposed gas after removing HF is supplied to the exhaust fan 6
Exhausted through the system. On the other hand, the waste liquid containing HF and SiO ₂ separated and removed from the exhaust gas is guided to a drainage facility (not shown) of a semiconductor factory via a pump 7 and neutralized.

Hereinafter, each embodiment of the present invention, namely, the embodiment relating to the exchange of the catalyst by the cartridge and the integration with small heat loss, the embodiment relating to the exchange of the catalyst without the cartridge and another integration, and the use of the pre-spray Third Embodiment A third embodiment related to the improvement will be described. Embodiment 1 FIG. 1 shows an apparatus for treating a fluorine-containing organic halogen compound according to one embodiment. When used in a clean room of a semiconductor factory, in order to reduce the installation space, the heater 2 to the cooler 4 of the processing apparatus are generally flange-coupled as shown in FIG.

In the processing apparatus of this embodiment, the outer tube 101 and the inner tube 102 of the heater 2 and the reactor 3 are shared, and the outer tube 101
Flange 135 of the inner tube and lower flange 13 of the inner pipe 102
6 is fixed with bolts, and the heater 2 and the reactor 3 are integrally formed.

The heater 2 is provided with a heater 8 and a heat insulating material 20 covering the heater 8 in an upper space defined by inserting a disk 104 into a small diameter portion above the inner tube 102. A gap 23 is provided between the disk 104 and the outer tube 101. This prevents the heat of the high-temperature gas (700 ° C.) transmitted through the inner tube 102 from being released to the outside via the outer tube 101, thereby reducing heat loss. In addition, since the heater and the reactor have an integrated structure, the structure of the fluorine-containing organic halogen compound processing apparatus is simplified, and the manufacturing cost can be reduced.

The reactor 3 is formed in a lower space defined by an outer tube 101, an inner tube 102, and a disk 104.
Is loaded with a catalyst cartridge 10 filled with a catalyst 9 in the lower space of. The lower flange 135 is fixed to a flange 141 provided above the cooler 4 with bolts. In the lower space between the outer tube 101 and the inner tube 102, a heater for keeping heat (not shown) is installed in the same manner as in the case of the heater 2.

FIG. 4 shows the catalyst cartridge 10 and the reactor 3.
2 shows a detachable structure at the lower part of FIG. The figure shows a state in which the lower part of the reactor 2 is enlarged, the connection with the upper flange 141 of the cooler 4 is removed, and the catalyst cartridge 10 is taken out below.

The catalyst cartridge 10 has a cylindrical body with a bottom plate and a flange 105. When the plurality of projections 106 provided on the lower flange 105 are engaged with the grooves 108 formed on the inner peripheral side of the lower flange 135 of the outer tube 101 and the flange 105 is turned, the catalyst cartridge 10 is fixed to the reactor 3. You. When the flange 105 is turned in the opposite direction, the catalyst cartridge 10 can be removed from the reactor 3.

Details of the replacement operation of the catalyst cartridge 10 will be described with reference to FIG. When the catalyst 9 reaches the end of its life, the catalyst cartridge 10 is replaced with a new catalyst cartridge. For attaching and detaching the catalyst cartridge 10, a cartridge attaching / detaching device 51 shown in FIG. 7 is used. The cartridge attaching / detaching device 51 includes a lifter 53, a turntable 52 rotatably provided on the lifter 53, and a rotation handle 54. The cartridge attaching / detaching device 51 includes:
After the flange 141 is removed from the lower flange 135 and the cooler 4 is shifted laterally below the reactor 3, the cooler 4 is positioned below the catalyst cartridge 10. The turntable 52 is raised by the lifter 53. The rubber stretched on the upper surface of the turntable 52 serves as a flange 105 of the catalyst cartridge 10.
Is contacted. The operation of the rotary handle 54 allows the turntable 5
2 is rotated. This rotational force is transmitted to the catalyst cartridge 10 via the rubber, and the catalyst cartridge 10 also rotates. When the projection 106 provided on the flange 105 reaches a predetermined position by this rotation, the rotation of the turntable 52 is stopped and the lifter 53 is lowered. The protrusion 106 is the groove 108
Removed from The engagement state between the flange 105 and the lower flange 135 is released. Further, by lowering the lifter 53, the catalyst cartridge 10 is pulled out from the inner tube 102.

Thereafter, a new catalyst cartridge 10 is placed on the turntable 52. A new catalyst cartridge 10 is inserted in the inner tube 1 of the reactor 3 in the reverse order of the above removal.
02 and attached to the lower flange 135.
The protrusion 106 of the new catalyst cartridge 10 is
Is adjusted to the predetermined position by the rotation of. Lifter 53
Is raised to raise the protrusion 106 to the position of the groove 108, and then the turntable 52 is rotated using the rotary handle 54 in a direction opposite to the direction in which the turntable 52 was removed, so that the protrusion 106 is engaged with the groove 108. Thus, a new catalyst cartridge 1
0 is installed in the reactor 3. Cartridge attaching / detaching device 5
1 is removed from the lower side of the catalyst cartridge 10 to which the cooler 4 is attached, and the cooler 4 is connected to the reactor 3 by attaching the flange 141 to the lower flange 135. Thus, the decomposition treatment of the fluorine-containing organic halogen compound by the fluorine-containing organic halogen compound treatment apparatus of the present embodiment can be restarted.

As a result, the catalyst cartridge 10 containing the catalyst 9 can be easily attached to and detached from the lower portion of the heater 2, and replacement of the catalyst can be simplified. In addition, since the scattering of the granular catalyst and the generation of dust due to the work can be prevented, the replacement work in the clean room becomes possible. In addition, since a tool can be applied to the rotation of the lower flange of the heater, the removal operation of the catalyst cartridge is easy, and the replacement in a high temperature state is possible, so that the operation time can be greatly reduced. Various changes can be made to the attachment and detachment of the cartridge by other well-known attachment / detachment mechanisms such as fastening with screws.

Embodiment 2 FIG. 5 shows an apparatus for treating a fluorine-containing organic halogen compound according to another embodiment. In this processing apparatus, only the outer tube 101 of the heater 2 and the reactor 3 is integrated,
The inner tube 22 of the heater 2 and the inner tube 32 of the reactor 3 are separate bodies,
The respective flanges 122 and 133 are fixed with bolts. A gap 23 is provided between the connected flange portion and the outer tube 101 to prevent heat from radiating to the outside.

The reactor 3 includes a lower flange 1 of the outer tube 101.
35 and the lower flange 134 of the inner tube 32 are fixed with bolts,
A bottom plate 107 for holding the catalyst 9 is provided below the inner tube 32. The bottom plate 107 is configured to be slidable with the inner peripheral side of the lower flange 134, and moves the bottom plate 107 to take out the internal catalyst 9 downward.

According to this embodiment, an integrated structure with little heat dissipation and exchange of the catalyst from the lower part of the reactor become possible.
It is to be noted that a modification in which the catalyst cartridge of the first embodiment or the integrated structure including the inner tube is applied to the present embodiment is possible.

[Embodiment 3] FIG. 6 shows a configuration of a front spray according to an embodiment. Exhaust gas (dry etching gas) containing SiF ₄ is introduced from the inlet pipe 12 into the front spray 1. Here, the inlet pipe 12 extends to the inside of the pre-spray 1, and the outlet 15 is provided downward, thereby preventing water of the spray 11 from scattering and entering the inlet pipe 12. Thereby, Si by the reaction of Chemical Formula 1
O ₂ precipitation is suppressed, and clogging of the piping is prevented.

A diffusion plate 14 filled with filler is provided at the lower part of the spray 11 so that the spray water diffuses and flows in the room, and the contact rate between the SiF ₄ discharged from the outlet 15 and the spray water is increased. In addition, the performance of removing impurities in the front spray is improved. By the way, front spray 1
Since HF is generated by the reaction of Chemical formula 1, it is composed of a corrosion-resistant vinyl chloride material or the like. While PVC has corrosion resistance, its heat resistance temperature is as low as about 100 ° C.

In this embodiment, a ball check valve 13 is provided at the exhaust gas outlet 16 of the front spray 1. This prevents the hot gas from flowing backward from the downstream side, that is, from the heater 2 when the processing apparatus is stopped, thereby preventing the PVC material of the front spray from being thermally damaged.

[0042]

According to the present invention, the replacement of the catalyst can be facilitated by opening and closing the lower part of the reactor. In particular, by making the catalyst cartridge detachable at the lower part of the reactor, there is an effect that the operation time is greatly reduced and the operation in the clean room becomes possible.

In addition, since at least the outer tube of the heater and the reactor is integrally formed and a gap is provided between the inner tube and the outer tube in the heater, the heat efficiency is improved and the operating cost is reduced. There is an effect that can be reduced.

Further, since a structure for preventing blockage of the inlet pipe and a structure for preventing backflow from the heater are provided in the front spray of the processing apparatus, the failure of the front spray can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part of a processing apparatus (a heater and a reactor) according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a conventional processing apparatus.

FIG. 3 is a configuration diagram of an exhaust gas treatment system to which the present invention is applied.

FIG. 4 is a structural diagram showing attachment and detachment of a catalyst cartridge according to the first embodiment.

FIG. 5 is a configuration diagram of a main part of a processing apparatus (a heater and a reactor) according to a second embodiment.

FIG. 6 is a structural diagram of a front spray according to a third embodiment.

FIG. 7 is an explanatory diagram showing an attaching / detaching operation of the catalyst cartridge according to the first embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Pre-spray, 2 ... Heater, 3 ... Reactor, 4 ... Cooler, 5 ... Packing tower, 6 ... Air blower, 7 ... Pump, 8 ... Heater, 9 ... Catalyst, 10 ... Catalyst cartridge, 11 ... Spray, 12: inlet piping, 13: ball check valve, 14: diffusion plate, 15: outlet, 16: exhaust gas outlet, 21, 101
... outer tube, 22, 102 ... inner tube, 23 ... gap, 104
... disk, 105 ... flange, 106 ... projection, 107 ... bottom plate, 108 ... groove, 135, 136 ... lower flange.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B01D 53/86 B01J 21/00-38/74

Claims (6)

(57) [Claims] 1. A water are mixed, a heater for heating the gas to be treated to a Jo Tokoro reaction temperatures including fluorine-containing organic halogen compound, a built-in catalytic, contained in heated the gas to be treated
A reactor for decomposing the fluorine-containing organic halogen compound ,
A cooling device that cools the decomposition gas discharged from the reactor , wherein the heater is attached to the reactor, and the cooling device disposed below the reactor is the reactor.
Removably attached to the catalyst below the reactor
An apparatus for treating a fluorine-containing organic halogen compound, wherein the apparatus is configured to be more replaceable. 2. The apparatus for treating a fluorine-containing organic halogen compound according to claim 1, wherein a lower part of the reactor and a catalyst cartridge filled with the catalyst are detachably structured. 3. The apparatus for treating a fluorine-containing organic halogen compound according to claim 1, wherein the heater and the reactor are constituted by a double tube, and at least an outer tube is integrated. _4. A pre-spray for removing SiF ₄ contained in a gas to be treated containing a fluorine-containing organohalogen compound, and water,
A heater for heating the mixed the gas to be treated to a Jo Tokoro reaction temperature, a built-in catalysts, the heated the gas to be treated
A reactor for decomposing the fluorine-containing organic halogen compound contained therein; and a cooler for cooling the decomposed gas discharged from the reactor , wherein the heater is attached to the reactor, and is provided below the reactor. Placing the cooler in the reactor
Removably attached to the catalyst below the reactor
Is configured to allow more exchange, the front treated gas inlet of the location spray opening extends to the interior of the pre-spray, and the <br/> opening of the treated gas inlet down structure An apparatus for treating a fluorine-containing organic halogen compound, the apparatus comprising: 5. The method according to claim 4, wherein a diffusion means for diffusing the spray water is provided between the gas introduction portion to be treated and the spray disposed above the gas introduction portion in the pre-spray. Processing equipment for fluorine organic halogen compounds. 6. The method of claim 4 or claim 5, the pre-Symbol pre sprayed placed upstream of the heater, and the hot gas in the heater is prevented from flowing back to the pre-spray reflux An apparatus for treating a fluorine-containing organic halogen compound, comprising a blocking means.