JP2006116470A - Exhaust gas treatment method and exhaust gas treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust gas treatment method that is capable of enhancing the treatment efficiency of a gas discharged from a semiconductor manufacturing apparatus and to provide an exhaust gas treatment apparatus therefor. <P>SOLUTION: The exhaust gas treatment apparatus 1 is provided with a mixing part 5 to obtain a mixture (c) by mixing hydrochloric acid (b) with a gas (a) to be treated discharged from the semiconductor manufacturing apparatus 3, a reaction chamber 11 connected with the mixing part 5 and a plasma production part 31 to produce plasma 13 within the reaction chamber 11. The exhaust gas treatment apparatus 1 decomposes and treats the gas (a) to be treated by introducing the mixture (c) obtained by mixing the hydrochloric acid (b) with the gas (a) to be treated into the plasma 13 produced within the reaction chamber 11. The treatment efficiency can be enhanced when the exhaust gas treatment apparatus 1 is used. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method and a processing apparatus for gas discharged from a semiconductor manufacturing apparatus.

  Organic halogen compounds such as chlorofluorocarbon and trichlorethylene are widely used in solvents, refrigerants, digestive agents and the like. A method of decomposing an organic halogen compound by introducing a mixed gas of the organic halogen compound and water vapor into plasma is known (for example, see Patent Documents 1 and 2).

  On the other hand, in a semiconductor manufacturing apparatus, a gas is introduced into a chamber in order to perform processing such as deposition (also referred to as film formation), etching, or cleaning. Some of the gas may be discharged from the semiconductor manufacturing apparatus without being reacted.

  For example, a gas containing a fluorine compound having a C—F bond (hereinafter referred to as a fluorine compound-containing gas) may be discharged from the semiconductor manufacturing apparatus without being reacted. The fluorine compound-containing gas is mainly used in a cleaning process or an etching process. Examples of such a gas include perfluorocarbon (PFC) and hydrofluorocarbon (HFC).

In recent years, regulations on emission into the atmosphere have been studied for fluorine compound-containing gases from the viewpoint of preventing global warming. PFC, especially CF _4, has a strong warming effect because it has a strong binding energy between C and F and is not easily decomposed and is likely to remain in the atmosphere. For this reason, it is important to decompose or recover PFC, particularly CF ₄ , without discharging it into the atmosphere. However, it is difficult to decompose the fluorine compound-containing gas, particularly CF ₄ . A high temperature of about 1700 ° C. is required to sufficiently decompose and decompose the fluorine compound-containing gas, particularly CF ₄ . In order to avoid such high temperature processing, for example, CF ₄ is reacted with Ca to accumulate solid CaF ₂ in the processing apparatus, and when a certain amount of CaF ₂ is accumulated, the CaF ₂ in the processing apparatus is taken out. The method of collecting is common. An example of the processing method of CF ₄ is disclosed in Patent Document 3 below.

In addition, a gas containing a silicon compound containing hydrogen (hereinafter referred to as a silicon compound-containing gas) may be discharged from the semiconductor manufacturing apparatus without being reacted. The silicon compound-containing gas is mainly used in the deposition process. Examples of such a gas include monosilane (SiH ₄ ), TEOS {(Si (OC ₂ H ₅ ) ₄ }, trimethylsilane {(CH ₃ ) ₃ SiH}, and the like.

Since the silicon compound-containing gas has toxicity and flammability, its emission into the atmosphere is regulated. For this reason, various treatments are performed so as not to discharge the silicon compound-containing gas into the atmosphere. For example, when SiH ₄ is supplied into a chamber together with an oxidizing agent such as N ₂ O in order to form a SiO ₂ film, a heat treatment method is currently generally performed. In this processing method, the silicon compound-containing gas discharged from the chamber is combusted in air (oxygen) at a high temperature to form a SiO ₂ powder, thereby stabilizing the silicon compound-containing gas.

Further, a method of removing the SiO ₂ powder and cooling the exhaust gas treatment device and the exhaust pipe heated excessively is used. For example, (1) a method in which a large amount of air is blown into a reaction chamber in which exhaust gas is treated to blow off the SiO ₂ powder at the same time as cooling, and (2) cooling at the same time as the SiO ₂ powder is flowed in water. The method of doing is used. However, in the methods (1) and (2), various large-scale facilities such as air supply piping, exhaust piping, drainage piping, and wastewater treatment equipment are required. An example of a method for treating SiH ₄ is disclosed in Patent Document 4 below.
JP-A-3-90172 Japanese Patent Laid-Open No. 7-24081 Japanese Unexamined Patent Publication No. 2000-157837 Japanese Patent Laid-Open No. 10-169959

  It is desired to improve the processing efficiency when processing a gas discharged from the semiconductor manufacturing apparatus as described above, for example, a fluorine compound-containing gas or a silicon compound-containing gas.

  Therefore, an object of the present invention is to provide an exhaust gas treatment method and an exhaust gas treatment device that can increase the processing efficiency of gas discharged from a semiconductor manufacturing apparatus.

  In order to solve the above-described problems, the exhaust gas treatment method of the present invention includes a step of mixing hydrochloric acid with a gas to be treated discharged from a semiconductor manufacturing apparatus to obtain a mixture, and a step of introducing the mixture into plasma. “Hydrochloric acid” means an aqueous solution of hydrogen chloride.

  In the exhaust gas treatment method of the present invention, the gas to be treated is decomposed and treated by introducing into the plasma a mixture obtained by mixing hydrochloric acid with the gas to be treated. When this exhaust gas treatment method is used, the exhaust gas treatment efficiency can be increased. This is considered due to hydrogen ions and chlorine ions present in hydrochloric acid. Since hydrogen ions and chlorine ions have high reactivity, it is considered that they are easily combined with the constituent elements of the gas to be processed dissociated from the gas to be processed in plasma.

  In the step of obtaining the mixture, it is preferable to spray hydrochloric acid on the gas to be treated. Thereby, it becomes easy to mix the to-be-processed gas and hydrochloric acid in a mixture. Therefore, the exhaust gas treatment efficiency can be increased.

  In addition, the gas to be treated preferably contains a fluorine compound. In this case, the fluorine compound is decomposed and processed. This is presumably because hydrogen ions present in hydrochloric acid are preferentially bound to fluorine element (F) dissociated from the fluorine compound in the plasma. Since the binding energy of the HF bond (563.2 kJ / mol) is high, for example, HF is generated. In this case, it is unlikely that HF will decompose again and return to the original bond.

The fluorine compound preferably has a C—F bond. In this case, the fluorine compound having a C—F bond is decomposed and processed. This is because oxygen element (O) dissociated from water (H ₂ O) in hydrochloric acid is preferentially combined with carbon element (C) dissociated from a fluorine compound having a C—F bond in plasma. Conceivable. Since the bond energy of the C═O bond (678.1 kJ / mol) is higher than the bond energy of the C—F bond (441.0 kJ / mol), for example, CO ₂ is generated. In this case, it is unlikely that CO ₂ will decompose again and return to the original bond.

Moreover, it is preferable that the gas to be treated contains a silicon compound having hydrogen. In this case, the silicon compound containing hydrogen is decomposed and processed. This is presumably because chlorine ions existing in hydrochloric acid are preferentially bonded to silicon element (Si) dissociated from the silicon compound having hydrogen in the plasma. Since the bond energy of the Si—Cl bond (358.6 kJ / mol) is higher than the bond energy of the Si—H bond (294.6 kJ / mol), a compound having an Si—Cl bond, for example, SiCl _x (x = 1) ~ 4) are generated. In this case, it is unlikely that the compound having a Si—Cl bond is decomposed again to return to a silicon compound having hydrogen such as SiH ₄ .

  The plasma is preferably inductively coupled high-frequency plasma generated under atmospheric pressure. In this case, since the plasma density can be increased, the processing efficiency of the gas to be processed can be increased. Further, since plasma is generated under atmospheric pressure, for example, pressure control such as decompression is unnecessary.

  Further, the exhaust gas treatment apparatus of the present invention generates a plasma in a reaction chamber connected to the mixing section, a mixing section that mixes hydrochloric acid with the gas to be processed discharged from the semiconductor manufacturing apparatus, and a reaction chamber connected to the mixing section. A plasma generation unit.

  In the exhaust gas treatment apparatus of the present invention, the gas to be treated is decomposed and treated by introducing a mixture obtained by mixing hydrochloric acid into the gas to be treated into the plasma generated in the reaction chamber. When this exhaust gas treatment apparatus is used, the exhaust gas treatment efficiency can be increased. This is considered due to hydrogen ions and chlorine ions present in hydrochloric acid. Since hydrogen ions and chlorine ions have high reactivity, it is considered that they are easily combined with the constituent elements of the gas to be processed dissociated from the gas to be processed in plasma.

  Moreover, it is preferable that a mixing part has a spraying apparatus which sprays hydrochloric acid on to-be-processed gas. By spraying hydrochloric acid, the gas to be treated and the hydrochloric acid in the mixture can be easily mixed. Therefore, the exhaust gas treatment efficiency can be increased.

  The exhaust gas treatment device preferably further includes a scrubber connected to the reaction chamber. In this scrubber, a part of the reaction product obtained in the reaction chamber is recovered by dissolving in water.

  In addition, the gas to be treated preferably contains a fluorine compound. In this case, the fluorine compound is decomposed and processed. This is presumably because hydrogen ions existing in hydrochloric acid are preferentially combined with fluorine element (F) dissociated from the fluorine compound in the plasma generated in the reaction chamber. Since the binding energy of the HF bond (563.2 kJ / mol) is high, for example, HF is generated. In this case, it is unlikely that HF will decompose again and return to the original bond.

The fluorine compound preferably has a C—F bond. In this case, the fluorine compound having a C—F bond is decomposed and processed. This is because oxygen element (O) dissociated from water (H ₂ O) in hydrochloric acid in the plasma generated in the reaction chamber has priority over carbon element (C) dissociated from a fluorine compound having a C—F bond. It is thought that it is combined. Since the bond energy of the C═O bond (678.1 kJ / mol) is higher than the bond energy of the C—F bond (441.0 kJ / mol), for example, CO ₂ is generated. In this case, it is unlikely that CO ₂ will decompose again and return to the original bond.

Moreover, it is preferable that the gas to be treated contains a silicon compound having hydrogen. In this case, the silicon compound containing hydrogen is decomposed and processed. This is presumably because chlorine ions present in hydrochloric acid are preferentially bonded to silicon element (Si) dissociated from the silicon compound having hydrogen in the plasma generated in the reaction chamber. Since the bond energy of the Si—Cl bond (358.6 kJ / mol) is higher than the bond energy of the Si—H bond (294.6 kJ / mol), a compound having an Si—Cl bond, for example, SiCl _x (x = 1) ~ 4) are generated. In this case, it is unlikely that the compound having a Si—Cl bond is decomposed again to return to a silicon compound having hydrogen such as SiH ₄ .

  Moreover, it is preferable that a plasma production | generation part has a plasma production | generation apparatus which produces | generates inductively coupled high frequency plasma in a reaction chamber under atmospheric pressure. In this case, since the plasma density in the reaction chamber can be increased, the processing efficiency of the gas to be processed can be increased. Moreover, since plasma is generated under atmospheric pressure, this exhaust gas treatment apparatus does not require, for example, a pressure control device such as a decompression device.

  According to the exhaust gas treatment method and the exhaust gas treatment apparatus of the present invention, the treatment efficiency of the gas discharged from the semiconductor manufacturing apparatus can be increased.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same reference numerals are used for the same or equivalent elements, and duplicate descriptions are omitted.

[Exhaust gas treatment equipment]
FIG. 1 is a schematic diagram showing an exhaust gas treatment system 10 including a semiconductor manufacturing apparatus 3 and an exhaust gas treatment apparatus 1 of the present embodiment. The exhaust gas treatment apparatus 1 is connected to a gas discharge port of the semiconductor manufacturing apparatus 3 by a pipe 33. An exhaust pump 23 is interposed between the exhaust gas treatment apparatus 1 and the semiconductor manufacturing apparatus 3. A gas to be processed (exhaust gas) a discharged from the semiconductor manufacturing apparatus 3 is introduced into the exhaust gas processing apparatus 1 through the pipe 33 by the exhaust pump 23.

  Examples of the semiconductor manufacturing apparatus 3 include a CVD apparatus, a dry etching apparatus, and a multi-chamber type semiconductor manufacturing apparatus that is connected and arranged in combination.

Examples of the gas to be treated a include fluorine compounds such as perfluorocarbon (PFC) and hydrofluorocarbon (HFC). More specifically, for example, a fluorine compound having a C—F bond such as CF ₄ , C ₂ F ₆ , CHF ₃ , C ₄ F ₆ , C ₄ F ₈ , or a fluorine compound such as NF ₃ may be used. . The gas to be treated a may be a fluorine compound that does not contain elemental chlorine (Cl). Fluorine compounds that do not contain chlorine elements are difficult to be decomposed due to their large binding energy. However, when the exhaust gas treatment device 1 is used, the treatment efficiency can be increased. Examples of the gas to be treated a include hydrogen-containing silicon compounds such as monosilane (SiH ₄ ), TEOS {(Si (OC ₂ H ₅ ) ₄ }, and trimethylsilane {(CH ₃ ) ₃ SiH}. The processing gas a may be a gas containing both a silicon compound having hydrogen and a fluorine compound.

The exhaust gas processing apparatus 1 includes a mixing unit 5 that mixes droplets of hydrochloric acid b with a gas to be processed a passing through a pipe 33 to obtain a mixture c. The mixing unit 5 includes a hydrochloric acid supply source 7 that supplies hydrochloric acid b, and a pipe 37 that connects the hydrochloric acid supply source 7 to the pipe 33. The hydrochloric acid b is supplied into the pipe 33 through the pipe 37. The flow rate of hydrochloric acid b is prepared by a mass flow controller (MFC) 25. For example, hydrochloric acid b is supplied from the hydrochloric acid supply source 7 to the mass flow controller 25 at a pressure of 2.026 × 10 ⁵ Pa (2 atm), and is piped from the mass flow controller 25 at a pressure of 1.013 × 10 ⁵ Pa (1 atm), for example. 33. Since the hydrochloric acid b is an aqueous solution of hydrogen chloride (HCl), the mixture c becomes a gas-liquid mixture. As hydrochloric acid b, commercially available 37% hydrochloric acid can be used. By using commercially available inexpensive hydrochloric acid, the processing cost of the gas to be processed a can be reduced. The concentration of hydrochloric acid b is not limited to this.

  In this embodiment, the mixing part 5 has the spraying apparatus 35 which sprays hydrochloric acid b on the to-be-processed gas a. Examples of the spray device 35 include a spray nozzle, a shower nozzle, a spray device using ultrasonic vibration, and a heating spray device. One diameter of the spraying device 35 is preferably 4.35 mm, for example. Specifically, for example, a spray device 35 is provided at an end of the pipe 37 at a place where the pipe 37 is connected to the pipe 33. By supplying the mist-like hydrochloric acid b, the hydrochloric acid b is easily dispersed uniformly in the gas to be processed a, so that the gas to be processed a and hydrochloric acid b in the mixture c are easily mixed.

  Further, the exhaust gas treatment apparatus 1 includes a reaction chamber 11 that receives the mixture c from the mixing unit 5 through a pipe 33 and a plasma generation unit 31 that generates plasma 13 in the reaction chamber 11. When the mixture c is introduced into the plasma 13 in the reaction chamber 11, the gas to be processed a is decomposed and processed. Thereby, the reaction product d is obtained.

At both ends of the reaction chamber 11, an inlet 11c and an outlet 11d are provided. The end of the pipe 33 is connected to the inflow port 11c. The mixture c is introduced into the reaction chamber 11 from the inlet 11c, and the reaction product d is discharged from the outlet 11d. The reaction chamber 11 has a cylindrical inner wall 11a and an outer wall 11b made of, for example, heat-resistant aluminum oxide (Al ₂ O ₃ ).

  In the present embodiment, the plasma generator 31 is a plasma having a coil 9 made of a conductive wire wound around the inner wall 11a between the inner wall 11a and the outer wall 11b, and a high-frequency power source 29 electrically connected to the coil 9. A generation device 39 is provided. The high frequency power supply 29 supplies, for example, high frequency power of 2 to 5 kW to the coil 9. Therefore, in the present embodiment, the plasma 13 is inductively coupled high-frequency plasma. In this case, since the plasma density in the reaction chamber 11 increases, the processing efficiency of the gas to be processed a can be increased.

In the present embodiment, the plasma 13 is generated under atmospheric pressure (normal pressure). Therefore, the internal pressure of the reaction chamber 11 is, for example, 1.013 × 10 ⁵ Pa (1 atm), and it is not necessary to connect a pressure control device such as a decompression device to the reaction chamber 11. Can be simplified.

  When the plasma 13 is generated under atmospheric pressure, the plasma 13 becomes thermal equilibrium plasma, and the atomic temperature in the reaction chamber 11 and the electron temperature of the plasma 13 are substantially the same. This temperature is 5000-6000 degreeC, for example. When the plasma 13 is thermal equilibrium plasma, the temperature inside the reaction chamber 11 can be efficiently increased while keeping the temperature outside the reaction chamber 11 low.

  In order to cool the inner wall 11a which becomes high temperature, the water 19 flows between the inner wall 11a and the outer wall 11b. Further, the plasma 13 is intensively generated in the vicinity of the center in the reaction chamber 11 by a diaphragm 17 attached to the inner wall 11a. The tip of the diaphragm 17 serves as the ignition end of the plasma 13.

  In the present embodiment, a scrubber 15 is connected to the outlet 11 d of the reaction chamber 11. In the scrubber 15 on the downstream side of the reaction chamber 11, the reaction product d is cooled, and a part of the reaction product d (for example, an acidic component) is dissolved in water. In the scrubber 15, water is sprayed on the reaction product d that flows. The scrubber 15 has a drain port 28 and an exhaust port 27. From the drain port 28, drainage 20 in which a part of the reaction product d is dissolved in water is discharged. A gas phase component e of the reaction product d that did not dissolve in water is discharged from the exhaust port 27. In this manner, the scrubber 15 can dissolve a part of the reaction product d obtained in the reaction chamber 11 in water and collect it as the waste water 20.

In the exhaust gas treatment apparatus 1, the gas to be treated a is decomposed and treated by introducing a mixture c obtained by mixing hydrochloric acid b with the gas to be treated a into the plasma 13 generated in the reaction chamber 11. When the exhaust gas treatment apparatus 1 is used, the treatment efficiency of the gas to be treated a can be increased. This is considered to be due to hydrogen ions (H ⁺ ) and chlorine ions (Cl ⁻ ) present in hydrochloric acid b. Since hydrogen ions and chlorine ions have high reactivity, it is considered that they are easily combined with the constituent elements of the gas to be processed a dissociated from the gas to be processed a in the plasma 13.

[Exhaust gas treatment method]
Next, an exhaust gas treatment method according to the present embodiment that is preferably performed using the above-described exhaust gas treatment apparatus 1 will be described. FIG. 2 is a flowchart showing each step of the exhaust gas treatment method according to the present embodiment.

(Mixing process)
First, in the mixing unit 5 of the exhaust gas treatment apparatus 1, hydrochloric acid b is mixed with the gas to be treated a discharged from the semiconductor manufacturing apparatus 3 to obtain a mixture c (step S1). In this embodiment, hydrochloric acid b is sprayed on the gas to be processed a using the spraying device 35. Thereby, it becomes easy to mix the to-be-processed gas a and hydrochloric acid b in the mixture c.

(Introduction process)
Next, the mixture c is introduced into the plasma 13 in the reaction chamber 11 (step S2). Thereby, the constituent elements of the mixture c excited by the energy of the plasma 13 react in the reaction chamber 11. As a result, the gas to be processed a is decomposed and processed to obtain a reaction product d.

When the exhaust gas treatment method of this embodiment is used, the treatment efficiency of the gas to be treated a can be increased. This is considered to be due to hydrogen ions (H ⁺ ) and chlorine ions (Cl ⁻ ) present in hydrochloric acid b. HCl in hydrochloric acid b is ionized into hydrogen ions and chlorine ions in water. Since hydrogen ions and chlorine ions have higher reactivity than hydrogen elements and chlorine elements, it is considered that they are easily combined with constituent elements of the gas to be processed a dissociated from the gas to be processed a in the plasma 13. . The exhaust gas treatment method of this embodiment is simple because it does not require large-scale equipment.

  In the present embodiment, the plasma 13 is inductively coupled high-frequency plasma generated under atmospheric pressure. In this case, since the plasma density can be increased, the processing efficiency of the gas to be processed a can be increased. Further, since the plasma 13 is generated under atmospheric pressure, for example, pressure control such as decompression in the reaction chamber 11 is unnecessary.

  Hereinafter, (1) the case where the gas to be treated contains a fluorine compound and (2) the case where the gas to be treated contains a silicon compound having hydrogen will be described.

(1) When the gas to be treated contains a fluorine compound First, the case where the gas to be treated a contains a fluorine compound, particularly a fluorine compound having a C—F bond, for example, CF ₄ will be described. CF ₄ is one of fluorine compounds used for etching and cleaning. Even when the gas to be treated a is a fluorine compound containing no chlorine element such as CF ₄ , the treatment efficiency can be increased by using the exhaust gas treatment method of the present embodiment as will be described below.

A gas to be processed a including CF ₄ exhausted from the semiconductor manufacturing apparatus 3 by the exhaust pump 23 and hydrochloric acid b supplied from the hydrochloric acid supply source 7 flow into the pipe 33. Thereby, the to-be-processed gas a and hydrochloric acid b are mixed within the piping 33, and the mixture c is obtained. The mixture c enters the reaction chamber 11 through the inflow port 11 c and is introduced into the plasma 13 generated by the plasma generation unit 31. The mixture c is excited by the energy given by the plasma generator 31. Thereby, the reaction product d is obtained from the mixture c. Specifically, for example, the reaction is considered to proceed according to the following reaction formula (1).

CF ₄ + 4H ⁺ + 4Cl ⁻ + 2H ₂ O → 4HF + 4HCl + CO ₂ (1)

In this reaction, fluorine element (F) and carbon element (C) are dissociated from CF ₄ . The elemental fluorine preferentially binds to hydrogen ions (H ⁺ ) present in the hydrochloric acid b. As a result, HF having an HF bond having a higher binding energy than the C—F bond is generated as the reaction product d. On the other hand, substances having other bonds such as CCl and CH are also produced, but these bonds are unstable. Since HF dissolves in the water of the scrubber 15, it is recovered as waste water 20. In addition, HCl, which is one of the reaction products d, is also recovered as waste water 20.

The carbon element (C) dissociated from CF ₄ is preferentially bonded to the oxygen element (O) dissociated from water (H ₂ O) in hydrochloric acid b. As a result, CO ₂ having a bond energy C═O higher than the C—F bond is generated as the reaction product d. For this reason, it is possible to prevent carbon from adhering to the inner wall 11a of the reaction chamber 11 and the like, and therefore it is not necessary to remove the adhering carbon every certain period. CO ₂ is recovered from the exhaust port 27 as a gas phase component e. Therefore, the reaction product d is generated as a gaseous substance and is not generated as a solid substance.

Further, in order to treat 1 mol of CF ₄ (88 g), for example, 62 g of commercially available 37% hydrochloric acid is required, so that about 0.71 mol of HCl is required. On the other hand, when hydrogen chloride gas is used, in order to process 1 mol of CF ₄ , for example, 150 g of hydrogen chloride gas is required, so that about 4 mol of HCl is required. Therefore, when hydrochloric acid is used, the number of moles of HCl for treating 1 mol of CF ₄ is smaller than when hydrogen chloride gas is used. This indicates that the reaction rate between HCl and CF ₄ in hydrochloric acid is higher than the reaction rate between HCl and CF _{4 in} hydrogen chloride gas. Therefore, when hydrochloric acid is used, the processing efficiency of CF ₄ can be increased as compared with the case where hydrogen chloride gas is used.

An example of a commercial price of 62 g of 37% hydrochloric acid is 56 yen, and an example of a commercial price of 150 g of hydrogen chloride gas is 3000 yen. At this time, the cost required to treat 1 mol of CF ₄ with hydrochloric acid is reduced to 1/54 when hydrogen chloride gas is used.

(2) When the gas to be treated contains a silicon compound having hydrogen Next, the case where the gas to be treated a contains a silicon compound having hydrogen, for example, TEOS will be described. TEOS is one of the silicon compounds with hydrogen used in deposition. Since TEOS is toxic and flammable, its emission into the atmosphere is regulated.

  A gas to be processed a containing TEOS exhausted from the semiconductor manufacturing apparatus 3 by the exhaust pump 23 and hydrochloric acid b supplied from the hydrochloric acid supply source 7 flow into the pipe 33. Thereby, the to-be-processed gas a and hydrochloric acid b are mixed within the piping 33, and the mixture c is obtained. The mixture c enters the reaction chamber 11 through the inflow port 11 c and is introduced into the plasma 13 generated by the plasma generation unit 31. The mixture c is excited by the energy given by the plasma generator 31. Thereby, the reaction product d is obtained from the mixture c. Specifically, for example, each constituent element (Si, C, O, H) of TEOS is considered to react and stabilize as follows.

Si → SiCl ₄
C → CO ₂
O → CO ₂
H → H ₂

In this reaction, the Si—O bond of TEOS is dissociated, and CO ₂ having a C═O bond having a higher bond energy than that of the Si—O bond is generated as the reaction product d. On the other hand, the silicon element (Si) dissociated from the Si—O bond is preferentially bonded to chlorine ions (Cl ⁻ ) present in the hydrochloric acid b. As a result, SiCl ₄ having a Si—Cl bond is generated as the reaction product d. In addition, the C—H bond of TEOS is dissociated, and CO ₂ having a C═O bond having a higher bond energy than the C—H bond, and H ₂ having a H—H bond having a higher bond energy than the C—H bond, Is produced as reaction product d. Therefore, the reaction product d is generated as a gaseous substance and is not generated as a solid substance (for example, a powder of SiO ₂ ).

  As mentioned above, although preferred embodiment of this invention was described in detail, this invention is not limited to the said embodiment.

  For example, the plasma 13 is generated under atmospheric pressure, but may be generated under reduced pressure. Further, although the plasma 13 is inductively coupled high-frequency plasma, it is not limited to this.

  The exhaust gas treatment device 1 may not include the scrubber 15. A part of the reaction product d may be recovered by an apparatus other than the scrubber.

It is the schematic which shows the exhaust gas processing system provided with the semiconductor manufacturing apparatus and the exhaust gas processing apparatus of embodiment. It is a flowchart which shows each process of the waste gas processing method which concerns on embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Exhaust gas processing apparatus, 3 ... Semiconductor manufacturing apparatus, 5 ... Mixing part, 11 ... Reaction chamber, 13 ... Plasma, 15 ... Scrubber, 31 ... Plasma generating part, 35 ... Spraying apparatus, 39 ... Plasma generating apparatus, a ... Cover Process gas, b ... hydrochloric acid, c ... mixture.

Claims (13)

A step of mixing hydrochloric acid with a gas to be processed discharged from a semiconductor manufacturing apparatus to obtain a mixture;
Introducing the mixture into a plasma;
An exhaust gas treatment method comprising:   The exhaust gas treatment method according to claim 1, wherein in the step of obtaining the mixture, hydrochloric acid is sprayed on the gas to be treated.   The exhaust gas treatment method according to claim 1 or 2, wherein the gas to be treated contains a fluorine compound.   The exhaust gas treatment method according to claim 3, wherein the fluorine compound has a C—F bond.   The exhaust gas treatment method according to any one of claims 1 to 4, wherein the gas to be treated contains a silicon compound having hydrogen.   The exhaust gas treatment method according to any one of claims 1 to 5, wherein the plasma is inductively coupled high-frequency plasma generated under atmospheric pressure. A mixing unit that mixes hydrochloric acid with the gas to be processed discharged from the semiconductor manufacturing apparatus to obtain a mixture;
A reaction chamber connected to the mixing section;
A plasma generator for generating plasma in the reaction chamber;
An exhaust gas treatment apparatus comprising:   The exhaust gas treatment apparatus according to claim 7, wherein the mixing unit includes a spray device that sprays hydrochloric acid onto the gas to be treated.   The exhaust gas treatment apparatus according to claim 7 or 8, further comprising a scrubber connected to the reaction chamber.   The exhaust gas treatment apparatus according to any one of claims 7 to 9, wherein the gas to be treated contains a fluorine compound.   The exhaust gas treatment apparatus according to claim 10, wherein the fluorine compound has a C—F bond.   The exhaust gas treatment apparatus according to any one of claims 7 to 11, wherein the gas to be treated contains a silicon compound having hydrogen.   The exhaust gas treatment apparatus according to any one of claims 7 to 12, wherein the plasma generation unit includes a plasma generation apparatus that generates inductively coupled high-frequency plasma in the reaction chamber under atmospheric pressure.

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