JP2000271421A - Waste gas washing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the removing frequency of the adhered matter on a gas inlet pipe and also to improve the washing efficiency of waste gas with respect to a waste gas washing device that a turning water chamber is arranged at the upper end of an introducing pipe whose lower end is communicated to a water spray washing part and a waste gas introducing part forming water film on the inner surface of the introducing pipe by the turning flow of the washing water flowed down from a circular gap between the gas inlet pipe at its center is arranged at the proceeding stage of the water spray washing part. SOLUTION: A gas inlet pipe 30 of a waste gas introducing part 11 has a double pipe structure of an outside pipe and a inside pipe, and dry gas is supplied to a gap between the outside pipe and the inside pipe, and the lower end of the outside pipe coming into contact with washing water is interrupted from the waste gas to prevent an adhesive material from being adhered to the gas inlet pipe 30. Also, a waste gas washing device 10 which is compact and high in washing effect is formed by forming integrally a packed material treating part 16 at the post stage of the water spray washing part 14 and arranging a Venturi part 15 for transferring treated gas at the water spray washing part 14 to the packed material treating part 16, at the inside of the device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for cleaning exhaust gas containing an adhering substance, particularly exhaust gas containing a silane-based gas discharged from a semiconductor manufacturing process.

[0002]

2. Description of the Related Art Exhaust gas discharged from a semiconductor manufacturing process includes solid fine particles such as SiO ₂ , chlorine compounds such as HCl and Cl ₂ , monosilane (SiH ₄ ), dichlorosilane (SiH ₂ Cl ₂ ), chlorosilane ( Silane-based gas such as SiHCl ₃ ). Since the silane-based gas reacts with water and decomposes into SiO ₂ and a chlorine compound, the exhaust gas is cleaned by a water spray cleaning device. However, when water comes into the gas inlet pipe of the water spray cleaning device due to splashing of washing water or the like, the silane-based gas in the exhaust gas reacts with the water, and a sticky gel-like reaction product is formed in the gas inlet pipe. Precipitates, and solid fine particles such as SiO ₂ in the exhaust gas adhere to the deposits to grow deposits, so that the gas inlet pipe is closed in a short time. Therefore, it is necessary to frequently stop the operation of the semiconductor manufacturing process to remove the deposits in the gas inlet pipe.

[0003] US Patent No. 4,986,838 discloses an exhaust gas cleaning apparatus in which an exhaust gas introduction section for preventing the attachment of solid fine particles to a gas inlet pipe is provided in front of a water spray cleaning section. FIG. 3 shows the cleaning device, and FIG. 4 is an enlarged view of the exhaust gas introduction section.

[0004] As shown in FIG.
Is composed of a sprinkling washing section 104 composed of a lower washing chamber 102 and an upper washing chamber 103, and an exhaust gas introducing section 105 for introducing exhaust gas into the sprinkling washing section 104. The gas introduction unit 105 has an introduction pipe 1 whose lower end communicates with the lower cleaning chamber 102.
06, a peripheral wall 108 having a reduced diameter bottom 107 is provided, and a gas inlet pipe 109 is inserted into the center of the peripheral wall 108.
07 and a cylindrical swirling water chamber 111 having an annular gap 110 therebetween. When the washing water is supplied from the washing water inlet 112 in a tangential direction to the inner surface of the cylinder of the swirling water chamber 111 and the washing water is swirled in the swirling water chamber 111, the swirling water flow 113 flowing down from the annular gap 110 causes the introduction pipe 1 to flow.
A water film 114 is formed on the entire inner surface of the substrate 06.

[0005] In the sprinkling cleaning section 104, the lower cleaning chamber 102
Cleaning water is sprayed from the water spray nozzle 115 in the inside and the plurality of water spray nozzles 116 in the upper cleaning chamber 103, and the inside of the lower cleaning chamber 102 and the upper cleaning chamber 103 is filled with the cleaning water splash.

The exhaust gas flows through the gas inlet 105 into the sprinkler / washer 104 as shown by the arrow 117, and the lower sprinkler chamber 102 and the upper wash chamber 103 filled with the washing water splash.
While passing through, fixed particles such as SiO ₂ and the chlorine compound in the exhaust gas are trapped in the washing water, and the silane-based gas is
It is decomposed into O ₂ and chlorine compounds and is captured in the washing water.
The processing gas from which the solid fine particles and the chlorine compound have been removed is discharged into the atmosphere from the exhaust port 118, and the washing water contaminated with the solid fine particles and the chlorine compound is discharged from the discharge pipe 119.

By providing the exhaust gas introduction section 105 as described above in front of the water washing section 104, solid particulates are prevented from adhering to the inner surface of the introduction pipe 106 covered by the water film 114, and the lower cleaning chamber 102 Of the washing water in the gas inlet pipe 10
Since the washing water does not come to 9 and splashing of the washing water does not occur near the gas inlet pipe 109, adhesion of the solid fine particles to the gas inlet pipe 109 is prevented.

[0008]

However, in the exhaust gas introduction portion 105, as shown in FIG. 4, at the lower end of the gas inlet pipe 109 whose outer peripheral surface is in contact with the washing water, the silane-based gas in the exhaust gas and water are mixed. A gel-like reaction product precipitates, and solid fine particles such as SiO ₂ in the exhaust gas adhere to the reaction product, and the deposit gradually grows. Since the deposit is sticky, it is not easily peeled off by the swirling water stream 113, and water is constantly replenished by a capillary phenomenon in the deposit. Therefore, the deposit also exists inside the gas inlet pipe 109 where there is no moisture. Is expanding. If left unattended, the deposits will hinder the flow of exhaust gas in the gas inlet pipe 109 or hinder the formation of a uniform water film 114 in the inlet pipe 109. Debris removal is required.

In the exhaust gas cleaning apparatus 100 described above,
Since the cleaning process is only water spray cleaning, the gas-liquid contact effect between the exhaust gas and the cleaning water is not sufficient, and a part of the silane-based gas such as dichlorosilane remains without being decomposed. If unreacted silane-based gas remains in the processing gas, it is necessary to remove deposits in a gas transfer device such as an exhaust fan.

An object of the present invention is to provide an exhaust gas cleaning apparatus having an exhaust gas introduction section as described above, in which the frequency of removing deposits on the gas inlet pipe is further reduced and the cleaning effect is further enhanced. It is.

[0011]

The above objects can be achieved by the exhaust gas cleaning apparatus of the present invention. That is,
The exhaust gas treatment device of the present invention is as described in claim 1,
The gas inlet pipe of the exhaust gas introduction section is characterized by being formed of an outer pipe and an inner pipe which can be separated from each other at a distance from each other.

The gas inlet pipe is composed of an outer pipe and an inner pipe.
As a heavy pipe structure, by separating the inner pipe from the outer pipe whose outer peripheral surface is in contact with the washing water, the growth of the above-mentioned deposits on the inner surface of the inner pipe is eliminated. The frequency of deposit removal can be further reduced. Since the outer tube and the inner tube are separable, it is easy to remove deposits on the gas inlet tube.

According to a second aspect of the present invention, a dry gas is supplied to the gap between the outer pipe and the inner pipe, and the exhaust gas and the swirling water flow are shut off by the dry gas, thereby producing a highly sticky gel-like reaction. Since there is no contact between the exhaust gas and moisture which causes the deposition of the substance, the outer pipe and the inner pipe of the gas inlet pipe do not produce any deposit at the lower end. Any gas that does not contain moisture, such as dehumidified air and nitrogen gas, can be used as the drying gas, and only a small amount of the drying gas is required since only the lower end of the outer tube in contact with the water film needs to be cut off.

According to a third aspect of the present invention, a guide surface curved along the inner peripheral edge of the reduced diameter bottom is formed on the outer periphery of the outer pipe, so that the swirling water flow flowing down from the annular gap is reduced. Since it is smoothly guided along the lower surface to the inner surface of the introduction pipe, the amount of washing water for forming a water film on the inner surface of the introduction pipe can be reduced.

Further, in the exhaust gas cleaning apparatus according to the present invention, the filler processing section is formed integrally with the water spray cleaning section after the water spray cleaning section, and the processing gas of the water spray cleaning section is sucked to fill the filler processing section. A venturi section is provided at the upper part of the filler processing chamber.

According to this configuration, the unreacted silane-based gas remaining in the processing gas in the water spray cleaning section can be completely decomposed and removed in the filling processing section having high gas-liquid contact efficiency. In addition, by providing a venturi section inside the exhaust gas cleaning device that transfers the processing gas from the water spray cleaning section to the filler processing section, a compact exhaust gas cleaning apparatus with a high cleaning effect can be obtained, and a blower that requires removal of deposits is required. Therefore, an exhaust gas transfer device such as a fan is not required.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an exhaust gas cleaning apparatus according to the present invention will be described below with reference to FIGS. FIG. 1 is an overall view of an exhaust gas cleaning apparatus of the present invention, and FIG. 2 is a sectional view of a gas inlet portion.

As shown in FIG. 1, the exhaust gas cleaning apparatus 10 of the present invention includes an exhaust gas introduction unit 11 for introducing exhaust gas, a water spray cleaning unit 14 including a lower cleaning chamber 12 and a cleaning chamber 13, and a water spray cleaning unit 14. Venturi unit 1 for sucking processing gas
5 is formed integrally with the filler processing section 16 provided at the top,
The lower part of the device is a washing water tank 17. Cleaning water tank 17
Of cleaning water is sent to the header 19 by the pump 18, and from the header 19, the swirling water chamber 20 of the exhaust gas introduction unit 11, the water spray nozzle 21 in the lower cleaning chamber 12, the plurality of water nozzles 22 in the upper cleaning chamber 13, and the venturi It is supplied to the venturi nozzle 23 of the section 15. The cleaning water contaminated by contact with the exhaust gas flows down to the cleaning water tank 17. Fresh washing water is supplied into the washing water tank 17 through the supply pipe 24 to the filler processing section 16.
Is supplied to the lower part of the cleaning device 10 by the cleaning pump 18 together with the less-contaminated cleaning water flowing down from the filler processing section 16, and the contaminated cleaning water overflows from the outlet 25 and is separately processed. .

The exhaust gas introduction section 11 is provided with a swirling water chamber 20 at the upper end of an introduction pipe 26 whose lower end opens into the lower washing chamber 12.
In that a water film 29 is formed on the inner surface of the introduction pipe 26 by the swirling water flow 28 flowing down from the annular gap 27, which is almost the same as the gas introduction section 105 of the conventional exhaust gas cleaning apparatus 100 described with reference to FIGS. Although the gas inlet pipe 30 has a double pipe structure of an outer pipe 31 and an inner pipe 32,
1 is connected to a dry gas supply path 33.

In the exhaust gas introduction section 11 of the exhaust gas cleaning apparatus 10 of the present invention, as shown in FIG. 2, a peripheral wall 35 having a reduced diameter bottom portion 34 fixed to an upper portion of an introduction pipe 26, and a swirling water chamber 2
The upper tube 36 and the outer tube 31 whose upper end is fixed form the cylindrical swirling water chamber 20, and the outer tube 31 and the reduced diameter bottom 3
4, an annular gap 27 is formed. The washing water is supplied tangentially to the inner surface of the swirling water chamber 20 through the supply path 37 inside the peripheral wall 35. Inner tube 32 is holding member 3
8, the upper end of the inner pipe 32 is connected to the exhaust pipe 40 via the connecting member 39, and a gap is provided between the lower end of the inner pipe 32 and the outer pipe 31. 41 are formed. Dry gas is supplied to the gap 41 through the supply path 33 inside the upper lid 36. A guide surface 42 curved along the inner peripheral edge of the reduced diameter bottom portion 34 of the swirling water chamber is formed on the outer periphery of the outer tube 31 in the annular gap 27.

As described above, the gas inlet pipe 30 has a double pipe structure, and the inner pipe 32 is separated from the outer pipe 31 which is in contact with the washing water. Deposits do not grow due to lack of replenishment. Therefore, the exhaust gas introduction unit 105 of the conventional apparatus 100
The frequency of removing the deposits on the gas inlet tube 30 is reduced as compared with the case of FIG. Since the outer tube 31 and the inner tube 32 can be separated,
It is easy to remove deposits. Further, by supplying a dry gas to the gap 41 and blocking the lower end of the outer tube 31 from the exhaust gas, the deposition of the reaction product and the attachment of solid fine particles to the lower end of the outer tube 31 are prevented, and the gas inlet tube 30 Almost no need to remove extraneous matter. The dry gas supplied to the gap 41 may be any gas that does not contain moisture, such as nitrogen gas and dehumidified air, and only the lower end of the outer tube 31 that is in contact with the washing water needs to be shielded. The guide surface 42 formed on the outer surface of the outer tube 32 guides the swirling water flow 28 flowing down from the annular gap 27 smoothly to the inner surface of the inlet tube 26 along the lower surface of the reduced diameter bottom portion 34. Of the introduction pipe 26
The amount of washing water for forming the water film 29 on the inner surface of the substrate is small.

Further, in the exhaust gas cleaning apparatus 10 of the present invention, the processing gas of the water spray cleaning section 14 is sucked by the flow of the cleaning water sprayed from the venturi nozzle 23 to the venturi section 15 and sent to the filler cleaning section 16. It is. Due to good gas-liquid contact in the filler cleaning section 16, all unreacted silane-based gases are decomposed into SiO ₂ and chlorine compounds and taken into the cleaning water. The processing gas washed in the filler processing unit 16 is discharged outside through the exhaust pipe 43.

In the above, the exhaust gas of the semiconductor manufacturing process containing a silane-based gas has been described as the exhaust gas containing the adhering substance. However, the exhaust gas cleaning apparatus of the present invention uses the phosphorus halide, arsenic, boron, siborane and other adsorbents. It can also be applied to exhaust gas cleaning processing containing substances.

[0024]

According to the present invention, the gas inlet pipe of the exhaust gas introduction section has a double-pipe structure with a space therebetween, and the inner pipe is separated from the outer pipe in contact with the washing water. By supplying the drying gas to the gap between the outside and the inside to block the lower end of the outer tube from the exhaust gas, it is almost unnecessary to remove the deposit on the gas inlet tube.

A filler treatment section having a high gas-liquid contact effect is integrally formed in a stage subsequent to the sprinkling washing section having an exhaust gas introduction section in the preceding stage, and the processing gas in the sprinkling washing section is sucked into the inside of the washing device to fill the filler. By providing the venturi section for transferring to the processing section, a compact exhaust gas cleaning apparatus having a high cleaning effect can be obtained, and the installation of a gas transfer apparatus which needs to remove deposits becomes unnecessary.

[Brief description of the drawings]

FIG. 1 is an overall view of an exhaust gas cleaning apparatus of the present invention.

FIG. 2 is a sectional view of an exhaust gas introduction section of the exhaust gas cleaning device of the present invention.

FIG. 3 is an overall view of a conventional exhaust gas cleaning device.

FIG. 4 is a cross-sectional view of an exhaust gas introduction section of a conventional exhaust gas cleaning device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Exhaust gas cleaning apparatus 11 ... Exhaust gas introduction part 14 ... Sprinkle cleaning part 15 ... Venturi part 16 ... Filler processing part 20 ... Swirling water chamber 26 ... Introductory pipe 28. ..Swirl water flow 29 ・ ・ ・ Water film 30 ・ ・ ・ Gas inlet pipe 33 ・ ・ ・ Dry gas supply path

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (reference) B01D 50/00 501 B01D 50/00 501L F-term (reference) 4D031 AB10 AB29 AC02 BA01 BA04 BA06 BA10 DA04 EA01 4D032 AB06 AB09 AB10 AC05 AC07 AC08 AC21 AC39 AD01 AD04 AD06 AD09 BA03 BB07 BB17

Claims (4)

[Claims] 1. A water sprinkling and washing apparatus for exhaust gas containing an adhering substance, wherein a lower end forms a swirling water chamber at an upper end of an introduction pipe communicating with a sprinkling cleaning section, and a central gas inlet pipe and a center of the swirling water chamber are formed. An exhaust gas introduction unit that forms a water film on the inner surface of the introduction pipe by a swirling water flow flowing down from the annular gap between the reduced diameter bottom portion and the exhaust gas cleaning device provided at the preceding stage of the water spray cleaning unit. An exhaust gas cleaning apparatus characterized in that the pipe is formed of an outer pipe and an inner pipe which can be separated from each other at a distance from each other. 2. The exhaust gas cleaning apparatus according to claim 1, wherein a dry gas is supplied to a gap between the outer pipe and the inner pipe. 3. The exhaust gas cleaning apparatus according to claim 1, wherein a guide surface curved along an inner peripheral edge of the reduced diameter bottom portion is formed on an outer periphery of the outer pipe. 4. A filler processing section is integrally formed at a stage subsequent to the sprinkling washing section, and a venturi section for sucking a processing gas of the sprinkling cleaning section and transferring the processing gas to the filler processing section is provided above the filler processing section. The exhaust gas cleaning device according to claim 1.