TW524713B - Method and device for treatment and recovery of CVD waste gas - Google Patents

Abstract

A method and device for treatment and recovery of chemical vapor deposition (CVD) waste gas wherein a raw material gas and intermediate products contained in a CVD gas are converted to halides having high volatility to prevent the raw material gas or intermediate products from attaching to or accumulating in waste gas piping, whereby the gas and products can be separated and recovered as a reusable source, while maintenance costs can be reduced. Un-reacted raw material gas and intermediate products contained in a CVD waste gas are decomposed or converted by reaction to decompose a part thereof, following which hydrohalogenated silicon gas, and hydrogen chloride are separated and recovered. Or the whole of the raw material gas and intermediate products are decomposed to hydrogen chlorides so as to be recovered.

Description

524713 A7 B7

File: 7666pif.doc / 009 V. Description of the invention Π) Field of invention (please read the precautions on the back before filling out this page) The present invention relates to a chemical vapour deposition (Chemieal vapQF Deposition; CVD) exhaust gas treatment and recovery method and The device, detailed §, relates to the use of hydrohalogenated silicon gas to form an epitaxial film, polycrystalline film, or amorphous film of silicon during the semiconductor manufacturing process. And a method for treating and recovering exhaust gas discharged from a chemical vapor deposition (CVD) device & ^ _. BACKGROUND OF THE INVENTION One of the chemical vapor deposition processes for the production of silicon by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economics is an epitaxial (single crystal growth) process, which is used to make Field Effect Metal Oxide Semiconductors. A transistor (metal-oxide film), or an emitter layer forming a bipolar transistor. The Jingjing process usually uses silicon (hydrogen halide) gas such as trichlorosilane (TCS) or dichlorosilane (DCS) as the raw material air body and is introduced into the process chamber under the dilution of the gas. 'Heated on the substrate set in the process chamber to about 1100 degrees Celsius to thermally decompose the raw material gas, and sand was deposited on the substrate. The process conditions at this time are usually carried out in a pressure range from atmospheric pressure to about 100 Pa. On the other hand, the polycrystalline growth process is used to form the gate electrode or the bottom layer of a capacitor of a field-effect metal-oxide semiconductor. The polycrystalline growth process usually involves diluting a hydrohalogenated sand gas such as sand (substituting) chloroform or dichloro sand factory with hydrogen, and then introducing it onto a substrate installed in the process chamber and heating it to about 800 degrees Celsius to allow the raw material gas to be processed. Pyrolyzed and deposited on a substrate. At this time, the 4 paper sizes are in accordance with Chinese National Standard (CNS) A4 (210 X 297 mm). Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 524713

File: 7666pif.doc / 009 A7 B7 V. Description of the Invention (z) The process conditions are usually performed under a pressure of about 100 Pa. In addition, under the above-mentioned process, in order to accompany the management of wafer adsorption of moisture during wafer transfer into and out of the process chamber, a moisture measurement device is provided in the exhaust pipe system, for example, a Fourier transform is installed In the case of infrared (Fourier transform infrared, FT-IR) spectrometer. In the above-mentioned crystal growth process, the thermal weight that actually contributes to the accumulation of silicon is about 5% of the total introduction amount. Most of the remaining raw material gases do not help the accumulation, and the intermediate products (the total amount %) Is discharged from the chamber together with the exhaust gas. The exhaust gas exhausted from the room is detoxified by removing the raw material gas or intermediate products through the harm removal device, and then exhausted to the atmosphere by using the hydrogen of the carrier gas or the nitrogen of the degassing gas. At this time, in the epitaxial process, the intermediate products (by-products) that occur during this process may adhere to and accumulate on the inner surface of the exhaust pipe, causing the accumulation to block the exhaust pipe. The intermediate products include silicon and chlorine compounds or silicon and hydrogen compounds. A polymer was formed on the inner surface of the exhaust pipe at normal temperature. The polymer formed is a substance that is highly reactive (self-igniting or explosive) with moisture in the atmosphere, for example, it is changed to polysiloxane. Therefore, in order to remove the polymer adhering to the inner surface of the exhaust pipe, when the exhaust pipe is decomposed to the open atmosphere, various preparations and tips must be prepared, which will reduce the working efficiency of the chemical vapor deposition device. . In addition, in order to remove the polymer deposits, using an etching gas such as chlorine trifluoride to carry out the blemishes of the exhaust pipe can remove the intermediate products or polymers deposited on the inner surface of the pipe. However, since 5 paper sizes are applicable to China National Standard (CNS) A4 (210 x 297 mm) ------ J ---- i Packing -------- Order ------ --- (Please read the note on the back? Matters before filling out this page) 524713 A7 B7

File: 7 666pif. Doc / 009 V. Description of the Invention (3) Exhaust pipelines are corroded due to strong etchability, and in this case, the problem of holes in the pipelines exists. In addition, the etching gas of chlorine trifluoride and the raw material gas used in the epitaxial process cannot usually be treated with only one detoxification device, and the corresponding detoxification device must be used instead when the respective gases are vented. On the other hand, in order to prevent the adhesion and accumulation of intermediate products in the exhaust pipe, a method has been proposed in which the pipe is often heated to a temperature of about 150 degrees Celsius. However, under this method, when the temperature of a part of the pipeline is relatively low, intermediate products are selectively accumulated in the low-temperature part. Generally, the pipeline between the detoxification device and the chemical vapor deposition device will form a complex curved part due to the reduction of the installation area requirement, which makes it difficult to uniformly heat and keep the pipeline system. In the foregoing description, the pipeline is removed and the intermediate products accumulated in the low temperature part are removed for maintenance. In addition, in the case of detoxification of silicon (generation) chloroform or dichlorosilane, a scrubber using water is mostly used, and water is reacted with silicon (generation) chloroform or dichlorosilane to form solid silicon dioxide. The scrubber is provided with a means for removing silicon dioxide using circulating water. However, when silicon dioxide is removed, because it contains hydrogen, sand dioxide will react with hydrogen fluoride during the original discharge process. This operation requires regular maintenance of the detoxification device, which reduces the working efficiency of the chemical vapor deposition device, and incurs additional costs due to the drug cost or human cost of removing the generated silicon dioxide. The purpose of the present invention is to provide a chemical vapor deposition exhaust gas treatment. The paper size is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) ----, --- d --- ·- Packing -------- Order --------- Αφ (Please read the note on the back? Matters before filling out this page) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 524713

File: 7666pif.d〇c / 〇〇9 A7 --------- B7 V. Description of the invention (4) The collection method and device are used in the process of crystal growth, and the raw material gas used or in this process The generated highly volatile halide intermediate product undergoes a conversion reaction, so that the exhaust gas to the separation and recovery device does not adhere to and accumulate on the exhaust system pipeline, so as to obtain a resource and separation and recovery material with a high recycling price. , And can reduce the number of regular maintenance of exhaust lines or harm removal devices or become unnecessary. Invention 槪 | In order to achieve the above-mentioned purpose, the method for treating and recovering the chemical vapor deposition exhaust gas of the present invention is a method for treating the exhaust gas discharged from the chemical vapor deposition device after forming a silicon film by using a silicon hydrohalide gas. It has the characteristics that the unreacted raw material gas and intermediate products contained in the exhaust gas are subjected to decomposition treatment or conversion reaction treatment, and after a part of the decomposition, the silicon hydrohalide gas and hydrogen chloride are separated and recovered. It is heated to more than 400 degrees Celsius, and then brought into contact with an iron reactant for reaction, and the exhaust gas after the aforementioned conversion reaction treatment is subjected to rectification separation. In addition, the method of the present invention is a method for processing an exhaust gas discharged from a chemical vapor deposition device after forming a silicon thin film using a silicon hydrohalide gas, and includes an unreacted raw material gas contained in the exhaust gas and All the intermediate products are decomposed and the hydrogen chloride of the decomposed product is recovered. The aforementioned decomposition treatment is performed at a temperature between normal temperature and 500 degrees Celsius, and is thermally desorbed with an iron reactant. The chemical vapor deposition exhaust gas treatment and recovery device of the present invention is a device for processing the exhaust gas discharged from the chemical vapor deposition device after forming a sand film by using a hydrohalide gas, and is provided with Contains less than 7 paper sizes that are in accordance with Chinese National Standard (CNS) A4 specifications (210 X 297 mm) (Please read the precautions on the back before filling this page). TT --------- Ministry of Economic Affairs Printed by the Intellectual Property Bureau Employee Consumer Cooperative 524713 A7 B7

File: 7666pif.doc / 〇〇9 V. Description of the invention (b) Decomposition reaction means for decomposing a part of the raw material gas and intermediate products of the reaction, separating silicon hydrohalide from the exhaust gas derived from the aforementioned decomposition reaction means A means for separating hydrogen chloride, a gas-liquid contact means for contacting the hydrogen chloride separated by the aforementioned means with water, and a gas recovery means for reusing silicon hydrohalide. Also, the chemical vapor deposition exhaust gas treatment and recovery device of the present invention is a device for processing the exhaust gas discharged from the chemical vapor deposition device after forming a silicon film by using a silicon hydrohalide gas, and is provided with the aforementioned exhaust gas Decomposition reaction means for completely decomposing unreacted raw material gas and intermediate products contained therein into hydrogen chloride, and gas-liquid contact means for contacting hydrogen chloride derived from the aforementioned decomposition reaction means with water. The figure is simple and sharp. Figure 1 shows a system diagram of a chemical vapor deposition exhaust gas treatment and recovery device according to the first preferred embodiment of the present invention. Fig. 2 is a schematic system diagram showing an example of the reactor of the first preferred embodiment of the present invention. Fig. 3 shows a system diagram of a second preferred embodiment of the present invention. FIG. 4 shows a system diagram of a third preferred embodiment of the present invention. Fig. 5 is a schematic system diagram showing an example of a reactor according to a third preferred embodiment of the present invention. Fig. 6 is a graph showing the measurement results of changes in the gas composition flowing out of the reactor in the first example. Fig. 7 is a graph showing measurement results of changes in gas composition flowing out of the reactor in the second example. / 一 I I · I I I--I I Order --------- (Please read the notes on the back before filling this page) Printed by the Employees' Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 524713

File: 7666pif.doc / 009 A7 B7 Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs V. Description of the invention (G) Marking of the drawings 10: Chemical vapor deposition device 11: Substrate (wafer) 12: Process room 12a : Gas introduction part 12b: lead-out part 13: gas supply device 14: exhaust pump 15: heating stage 16: moisture measuring means 17: heating or holding means 21, 31: reactor 22: separator 23: recovery line 24, 32: Gas-liquid contact tanks 25, 26, 27, 33: Detailed description of the preferred embodiment of the pipeline. FIG. 1 shows a chemical vapor deposition exhaust gas treatment and recovery device of the first preferred embodiment of the present invention. System diagram. Fig. 2 is a schematic system diagram showing an example of a reactor according to the first preferred embodiment of the present invention. The object of the present invention is a chemical vapor deposition apparatus, that is, a chemical vapor deposition apparatus for forming a silicon thin film using a silicon hydrohalide gas. The chemical vapor deposition device 10 shown in this preferred embodiment is generally referred to as a single-lamp-heated epitaxial silicon device, and includes a substrate (wafer) 11 9 This paper size is applicable to Chinese national standards (CNS) A4 specification (210 X 297 mm) -------- y ---- I installed -------- order --------- (Please read the back first (Please fill in this page again) 524713

File: 7666pif.doc / 009 A7 B7 V. Process chamber 12 of the invention description (7), a gas supply device 1 for supplying raw material gas, washing gas, scavenging gas and carrier gas in the process chamber I2 1 and The gas is discharged from an exhaust pump 14 of the process chamber 12. The process chamber 12 is connected to a loading chamber (not shown) via a gate valve (not shown). In addition, in the process chamber I2, a heating means (irradiator: not shown) for heating the heating table (suSCeptor 15) on which the wafer 11 is mounted or the wafer Π to a predetermined temperature is provided. ° This chemical vapor deposition The device 10 uses an exhaust gas that is diluted by flowing a source gas under a diluent gas, and maintains the pressure in the process chamber 12 at about one atmosphere to perform epitaxial growth on the wafer 11. For example, 'a typical sequence for p-type epitaxial growth will be described, and by providing a flow rate of 2L (liter (the same applies hereinafter)) per minute of nitrogen containing scavenging gas into the process chamber The wafer is carried in through a gate valve and placed on a heating table. After closing the gate valve, switch the supply gas from nitrogen to chlorine. When the process chamber is replaced with a hydrogen atmosphere, heat the crystal gas (flow rate: 1.5L / min) to a temperature of 1200 ° C at 1200 ° C. (Please read first Note on the back, please fill out this page again.) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs-Atmospheric pressure in a hydrogen atmosphere. After flattening the wafer, the wafer will be heated at a temperature of 1 ° C and atmospheric pressure. Provide epitaxial growth gas, this process is 15 () 2 minutes. Normally, mix at 7 L / min hydrogen for minutes. Generally, a gas containing ^^ Π with a ratio of ^^ Π in 7 L / min of hydrogen and a nitrogen gas at 14 g / min of nitrogen is used. In the case where DCS (dichlorosilane) is used instead of TCS, the flow rate of the gas containing 150 cc / diborane is 10 g / min, and the temperature of the wafer 11 is 1 ° C. 8q degree DCS, and installed -------- ^ --------- 10 This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) Intellectual Property Bureau of the Ministry of Economic Affairs Printed by employee consumer cooperative 524713

File: 7666pif.doc / 009 A7 _____ B7 V. Description of the invention (8) When using η type instead of P type, phosphine should be provided instead of diborane. At this time, the 'flow rate is about the same as in the case of using diborane. After the processing is completed, the supply gas is switched from the epitaxial reaction gas to 10 L / min nitrogen, and the wafer having completed the predetermined processing is carried out. Next, the supply gas was switched to a mixed gas of nitrogen and hydrogen chloride gas, and the atmosphere of the mixed gas with a flow rate of 7 to 15 L / min was maintained, and maintained at 11 to 50 degrees Celsius under one atmosphere of pressure to remove the process chamber Attachments or deposits. Finally, the supply gas was returned to 10 L / min of nitrogen, and the temperature of the heating table was lowered to near normal temperature. The processing process of such a cycle is ended, and the original wafer is moved in. The various gases used in the above steps are introduced into the process chamber 12 by the gas supply device Π to perform the process. Gas switching is accompanied by the gas's own decomposition reaction. In particular, it can prevent the reaction of a small amount of moisture with the raw material gas such as TCS or DCS to decompose the raw material gas and adsorb it on the surface of the pipeline. Up to the entrance of the process room, it is preferred that the stainless steel be subjected to a heat treatment of about 400 degrees Celsius in a weakly oxidizing and strong reducing atmosphere to form a chromium oxide film on its inner surface or a stainless steel containing a few percent aluminum. In a weakly oxidizing and strong reducing atmosphere, a heat treatment of about 900 degrees Celsius is applied to form an aluminum oxide film on the inner surface. In addition, in accordance with the presence or absence of this decomposition reaction or the loading and unloading of wafers, in order to monitor the moisture concentration in the process chamber, a gas measurement unit 16 using optical means is installed in the gas introduction part 12a and the lead-out part 12b of the process chamber 12. In particular, the moisture measuring means 16 is preferably a light source that applies the Chinese National Standard (CNS) A4 specification (21 × 297 mm) to the paper size of the semiconducting paper. ------- Order --------- (Please read the notes on the back before filling this page) 524713

File: 7666pif.doc / 009 A7 B7 Printed by the Consumer Cooperative of Intellectual Property Bureau of the Ministry of Economic Affairs 5. Description of the invention) Laser spectrophotometer for volume laser measurement. In this way, the atmosphere in the process chamber can be accurately grasped and controlled, thereby reducing the phenomenon of dummy wires. On the other hand, a processing and recovery device for processing and recovering unreacted raw material gas and intermediate products contained in the exhaust gas discharged from the process chamber 12 is the aforementioned exhaust pump 14. For example, a screw pump (screw) The exhaust system piping of the pump) is provided with a reactor 21 having a decomposition reaction means for decomposing or reacting the unreacted raw material gas or high-boiling intermediate products contained in the exhaust gas, and having been processed by the aforementioned reactor 21 The separator 22 for separating the derived exhaust gas rectification into separated silicon hydrohalide gas and hydrogen chloride, and a method for using the silicon hydrohalide gas separated by rectification through the separator 22, for example, are used in the gas supply device 13. A recovery line 23 of a gas recovery means for TCS recovery and reuse, and a gas-liquid contact tank 24 having a gas-liquid contact means for contacting the separated hydrogen chloride with water after rectification. In the foregoing sequence, chemical vapor deposition Various gas components of the apparatus 10 in each step are discharged through the exhaust system pipe, and flowed into the aforementioned reactor 21 through the exhaust pump 14. In the foregoing description, the reactor 21 performs a decomposition treatment or a conversion reaction treatment on an unreacted raw material gas or an intermediate product contained in the exhaust gas, and appropriately processes a target gas component and a transition metal reactant. Heating to a predetermined temperature is preferably a method in which iron (Fe) is heated to 400 ° C or more to form an iron reactant and is in contact with the exhaust gas. The heating means for heating the transition metal reactant may be any device such as an electric heater. In this heating method, the heating temperature is in accordance with the cost of the paper. The Chinese national standard (CNS) A4 specification (210 X 297 mm) is applied (please read the precautions on the back before filling this page). --------- 524713 A7 B7

File: 7666pif.doc / 009 i. Description of the invention (\ 0) (Please read the notes on the back before filling this page) It varies, usually it is above 400 ° C, for example, it is preferably between 4 ° C 〇〇 degrees to 500 degrees Celsius. In addition, the material forming the reactor 21 or the heat-resistant temperature of the reactant will limit the heating conditions. When the temperature is higher than the necessary temperature, the effect of increasing the processing efficiency will be reduced, but the energy loss will be increased. When stainless steel is used in the reactor 21, heating to 500 degrees Celsius or more will dissociate hydrogen chloride gas or hydrogen gas to generate active hydrogen radicals, which may promote embrittlement. In addition, the reactor 21 is considered for maintenance (exchange or activation of reactants), and as shown in FIG. 2, a plurality of reactors 21 and 21 are arranged in parallel by a valve, which is suitable for switching. . In addition, the exhaust system pipeline to the reactor 21, that is, the outlet from the process chamber 12 to the exhaust pipeline of the reactor 21 through the exhaust pump I4, in order to prevent adhesions from occurring in the aforementioned pipeline, A heating means or a thermal insulation means 17 'is provided to cover the exhaust pipe at an appropriate temperature, for example, heating or thermal insulation is preferably about 150 degrees Celsius. In addition, when the gas temperature of the process chamber 12 is high, the heating means does not need to use a high-capacity heater, and a heat-insulating material can be wound around the exhaust pipe to obtain a complete thermal insulation effect. However, it is necessary to use appropriate heating methods or insulation methods corresponding to the length or material of the exhaust pipe. When the exhaust pipe printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs is short, and the temperature of the gas flowing into the reactor is sufficient, Can be omitted and not used. In the exhaust pipe described above, it is preferable to use the aforementioned chromium oxide or aluminum oxide film formed on the surface. At this time, heat treatment is applied to the pipeline path, and even in the presence of active chlorine radicals, unsuitable situations such as corrosion do not occur. This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) 524713

File: 7666pif.doc / 009 A7 B7 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 5. Description of the invention (\\) At this time, the exhaust gas formed by the chemical vapor deposition device 10 is introduced into the reactor 21, which contains A part of the TCS or DCS of the reaction raw material gas is reacted or transformed with its by-products to combine the generated hydrogen chloride and sand with a transition metal reactant or the like to generate a conversion reaction for removal. Similarly, boron or phosphorus in the 'diborium compound' or phosphine is removed by combining with the reagent. In this reaction, hydrogen is necessary. Although TCS or DCS itself has a hydrogen atom, in the foregoing description, during the normal epitaxial growth process, the atmosphere or diluent gas is the case where hydrogen is used. The problem is to make the conversion reaction easier. However, in the case where plasma is used to assist the growth reaction, etc., in the case where the hydrogen in the exhaust gas is insufficient, it is preferable to add hydrogen to the exhaust gas in the exhaust line that is cut off before the reactor 21. Means of adding hydrogen in the gas to add an appropriate amount of hydrogen. The exhaust gas discharged from the reactor 21 is introduced into a separator 22 to separate TCS or DCS having a raw material gas from hydrogen chloride. The structure or operation method of the separator 22 is to appropriately select the operating pressure, the rectification separation temperature, the number of stages of the rectification separator, etc., according to the composition of the exhaust gas, the type of the recovered raw gas, the recovery rate, and the purity. For example, using a rectification cylinder with seven stages and maintaining a pressure of 150 kPa and a temperature of 283 K, the TCS from the reactor 21 with a hydrogen chloride concentration of lpprn or less is introduced from the upper half of the separator 22 Take out, at this time, about 99% of the TCS introduction amount can be recovered. The silicon hydrohalide gas such as TCS obtained by separation is recycled to the gas supply device 13 through the recovery line 23 for reuse. 14 This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) (Please read the precautions on the back before filling this page). -------- Order ------- --Line one 524713

File: 7 666pif.doc / 00 9 A7 B7 Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs V. Invention Description (\ No)

On the other hand, the hydrogen chloride gas obtained by the rectification separation by the separator 22 is led out from the bottom of the separation benefit 22 to be introduced into the storage liquid contact tank 24, and is contacted by running water to form a hydrochloric acid solution, and then taken out from the pipeline 25. Moreover, the water used at this time is, for example, pure water having a relative resistance of about 18 MΩ · cm to generate a high-purity hydrochloric acid solution, and this hydrochloric acid solution may be reused. In addition, water can be purified to obtain insoluble harmless substance Q after reacting with hydrogen chloride. In addition, a small amount of unused diborane or phosphine, or a decomposition product containing boron or phosphorus, or Impurities such as reaction products are discharged through the pipe 26. In the reactor 21, silicon is combined with a transition metal reactant such as iron to form harmless iron silicide, which can be directly taken out from the reactor 21 after the conversion reaction is completed. In this case, when the purity of the reactant is high, for example, iron with a purity of 97% or more can be used to obtain high-purity iron silicide, which can be reused as ferritic steel. Fig. 3 shows a system diagram of a second preferred embodiment of the present invention. In the following description, the same components as those of the first preferred embodiment are denoted by the same symbols, and detailed descriptions thereof are omitted. In this preferred embodiment, as in the first preferred embodiment, the hydrogen chloride gas introduction pipe 27 led out from the reactor 21 and separated by the separator 22 is used to replace the gas-liquid contact tank 24 and circulate the gas back. The device 13 is supplied as a washing gas for reuse. In this way, the cost of hydrogen chloride required can be significantly reduced. -------- Order --------- Refer to (Please read the precautions on the back before filling this page) This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) ) 524713

File: 7666pif.doc / 009 A7 B7 V. Description of the invention) (Please read the notes on the back before filling out this page) Figure 4 shows the system diagram of the third preferred embodiment of the present invention. Fig. 5 is a schematic system diagram showing an example of a reactor according to a third preferred embodiment of the present invention. In the preferred embodiment, a reactor 31 having a decomposition reaction means capable of decomposing or converting the unreacted raw material gas or high-boiling intermediate products contained in the exhaust gas is connected to the exhaust system pipeline, and The gas-liquid contact tank 32 in which the hydrogen chloride gas derived from the reactor 31 is in contact with water to form a hydrochloric acid solution will be described as an example. The reactor 31 used here can decompose all the unreacted raw material gas or intermediate products in the exhaust gas, and use a transition metal reactant filled with, for example, iron, and use thermal desorption to heat the reactant. The heating means from normal temperature to 500 degrees Celsius is the same as the reactor of the first preferred embodiment, and any electric heater can be used. In addition, the reactor 31 does not consider switching between maintenance and thermal desorption. As shown in FIG. 5, at least three cylinders of reactors 31 and 31 arranged in parallel by a valve are preferably provided. Individual reactors that sequentially switch the three processes of heating process, cooling process, and waiting process. The Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs printed the introduction of the exhaust gas from the chemical vapor deposition device 10 into the reactor 31 constituted above to decompose or convert it with TCS, DCS or its by-products. Chlorine becomes hydrogen chloride and binds silicon to the transition metal in the reactant. Similarly, it is removed by combining with a reagent such as boron or phosphorus in diborane or phosphine. At this time, the gas discharged from the reactor 31 was almost converted into hydrogen chloride gas. In addition, the hydrogen chloride gas discharged from the reactor 31 is in contact with the water in the gas-liquid contact tank 32 connected downstream of the reactor 31. The paper size is in accordance with China National Standard (CNS) A4 (210 X 297 mm). 524713

File: 7666pif.doc / 009 A7 B7 V. Description of the invention (丨 4) A useful hydrochloric acid solution is prepared, and then taken out through the pipeline 33. (Please read the precautions on the back before filling this page.) In addition, when the hydrogen necessary for the reaction in the reactor 31 is insufficient, appropriate hydrogen can be added by using the aforementioned pathway. Further, after silicon and iron are combined in the reactor 31, iron silicide is formed in the same manner as described above, and it can be reused as a ferritic steel raw material. In addition, as for the water used in the gas-liquid contact tank 32, pure water having a relative resistance of about 18 MΩ · cm is used in the same manner as described above to obtain a high-purity hydrochloric acid solution. Above, the treatment of the chemical vapor deposition exhaust gas shown in the preferred embodiments to prevent deposits from adhering to the inner surface of the exhaust system piping, and the need to perform periodic maintenance to remove the deposits And, to improve the working efficiency of the chemical vapor deposition device, and the reuse of the raw material gas or the use of the processed product for other purposes can greatly reduce the cost required for the removal of the chemical vapor deposition exhaust gas. For example, the harm removal cost of the structure of the first preferred embodiment can be reduced to about 50% of the conventional harm removal cost, and the harm removal cost of the structure of the second preferred embodiment can be reduced to about 50% of the conventional harm removal cost. About 40%, the harm removal cost of the structure of the third preferred embodiment can be reduced to about 30% of the conventional harm removal cost. (Example) Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economy Example 1 In the device described in the first preferred embodiment, an FT-IR 'is installed on the downstream side of a reactor filled with an iron reactant. The composition of the gas flowing from the reactor was analyzed. In a chemical vapor deposition device, a hydrogen gas containing 2000 ppm of TCS was used as a test gas to form a film, and the temperature of the reactor was maintained at 450 degrees Celsius to measure 17 out of the reactor. CNS) A4 size (210 X 297 meals) 524713

File: 7666pif.doc / 009 A7 __B7 V. Description of the Invention (\ S) (Please read the notes on the back before filling this page) Changes in gas composition. The results are shown in Fig. 6. In the initial stage of the reactor operation, only moisture was observed within the aging effect of the reaction using iron (hydrogen removal of the vaporized iron film), and the test gas was used when the occurrence of moisture was reduced. It can be observed that TCS and hydrogen chloride reach a certain concentration. Moreover, no intermediate product was detected at all. Then, the gas flowing out of the foregoing reactor was introduced into the separator at a pressure of 150 kpa and a temperature of 283 K, and was subjected to rectification separation to confirm the separation performance. The separator used is a cylinder with a height of 6m, a number of layers of 7 餍, and a cylinder diameter of 180mm. The recovered amount of TCS is measured by measuring the hydrogen chloride concentration and recovered flow rate in TCS. The results showed that the concentration of hydrogen chloride in the recovered TCS was below the detection limit (less than 1 ppm), and the recovery rate of about 90% was calculated from the TCS flow rate and the recovered flow rate of the separator inlet estimated in Fig. 6. Example 2 The consumer cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs printed the device described in the third preferred embodiment. FT_IR was installed on the downstream side of the reactor filled with iron reactant to prevent the flow from the reactor. The gas composition is analyzed. In a chemical vapor deposition apparatus, hydrogen gas containing TCS containing 25 PPm was used as a test gas for film formation, and the temperature of the reactor was maintained at 600 degrees Celsius to measure the change in the composition of the gas flowing out of the reactor. The results are shown in Fig. 7. It is obvious from Fig. 7 that when the temperature range exceeding 400 ° C is used, TCS decomposes rapidly to generate hydrogen chloride. In this case, no intermediate product was detected at all. The hydrogen chloride flowing out of the reactor and the relative resistance are 17MΩ · cm. The paper size is applicable to China National Standard (CNS) A4 (210 X 297 mm) 524713

File: 7666pif.doc / 009 A7 B7 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs. 5. Description of the invention (\ u) Pure water is contacted with gas and liquid to generate hydrochloric acid solution. When the hydrochloric acid concentration is 35 wt%, the silicon concentration in hydrochloric acid is about 2 ppm, and metal contaminants such as iron cannot be detected. In the above description, the method and apparatus for treating and recovering the chemical vapor deposition exhaust gas of the present invention is to easily treat a part or intermediate products of unreacted raw gas in a chemical vapor deposition device to decompose or convert It reacts to hydrogen chloride, so that no deposits can be attached to the inner surface of the exhaust system pipeline, and regular maintenance is not required to remove the deposits, so as to improve the working efficiency of the chemical vapor deposition device. Further, the exhaust gas from the reactor is subjected to rectification and separation, so that the raw material gas can be reused while performing efficient separation. In addition, gases that can no longer be used, such as hydrogen chloride, can be easily harmless after being brought into gas-liquid contact with pure water, and the hydrochloric acid solution produced by the reaction becomes a new resource that can be reused. In addition, the method of thermal desorption in the reactor can completely decompose the raw material gas to obtain hydrogen chloride gas, and thus no maintenance is required. In this case, hydrogen chloride is reacted with pure water to obtain a reusable high-purity hydrochloric acid solution. Moreover, the efficient treatment of the chemical vapor deposition exhaust gas can improve the working efficiency of the chemical vapor deposition device, reduce the cost of harm removal, and improve the productivity to achieve a reduction in the overall cost. 19 —; —.— ^ 装 -------- Order --------- ^ wi (Please read the notes on the back before filling out this page) This paper size applies to Chinese National Standards (CNS ) A4 size (210 X 297 mm)

Claims (1)

524713 A8 B8 File: 7666pif.doc / 009 C8 — D8 6. Scope of patent application (please read the precautions on the back before filling this page) 1. A method for the treatment and recovery of CVD exhaust, which is suitable for the use of silicon monohydrogen halide The method for treating a gas forming a silicon film and exhausting it from a chemical vapor deposition device includes the following features: The exhaust gas contains an unreacted raw material gas and an intermediate product, and a transition metal reactant is used in the exhaust gas. Thermal desorption is performed between normal temperature and 500 degrees Celsius, and after a decomposition treatment or a conversion reaction treatment is performed to decompose a part, the silicon hydrohalide gas and hydrogen chloride gas are separated and recovered. 2. The method for treating and recovering CVD exhaust gas as described in item 1 of the scope of the patent application, wherein the conversion reaction treatment is heated to more than 400 degrees Celsius and then contacted with an iron reactant. 3. The method for treating and recovering CVD exhaust gas according to item 1 of the scope of the patent application, further comprising separating the hydrohalide gas and the hydrogen chloride gas after rectifying the exhaust gas after the conversion reaction treatment. 4. A method for treating and recovering CVD exhaust gas, which is a treatment method suitable for forming a silicon film using a silicon hydrohalide gas and discharging one of the exhaust gas from a chemical vapor deposition device, and its characteristics include: Intellectual Property Bureau of the Ministry of Economic Affairs The employee consumer cooperative prints an unreacted raw material gas and an intermediate product in the exhaust gas, and uses a transition metal reactant to perform thermal desorption between normal temperature and 500 degrees Celsius. After a complete decomposition process, the decomposition is performed. The product is recovered in hydrogen chloride gas. 5.—A CVD exhaust gas treatment and recovery device is a processing device suitable for forming a sand film using a hydrohalide sand gas and exhausting it from a chemical vapor deposition device. Its characteristics include: 20 paper sizes Applicable to China National Standard (CNS) A4 specification (210 X 297 mm) 524713 A8 B8 File: 7666pif.doc / 009 C8 _ _ D8 VI. The scope of patent application is to make the product contain an unreacted raw material gas and an intermediate product. A part of the exhaust gas is decomposed, a decomposition reaction method using a transition metal reactant to perform thermal desorption between normal temperature and 500 degrees Celsius; the exhaust gas derived from the decomposition reaction method is separated into the hydrohalide stone A means for separating gas from ~ 'hydrogen chloride gas; a gas-liquid contact means for contacting the hydrogen chloride gas separated by the separation means with water; and a gas recovery means for reusing the silicon hydrohalide gas. 6. species The CVD exhaust gas treatment and recovery device is a treatment device suitable for forming a silicon film using a silicon hydrohalide gas and discharging one of the gases from a chemical vapor deposition device. The characteristics include: In order to completely decompose the exhaust gas containing an unreacted raw material gas and an intermediate product into a hydrogen chloride gas, use a transition metal reactant to perform a thermal desorption reaction between normal temperature and 500 degrees Celsius; And a gas-liquid contact means for contacting the hydrogen chloride gas derived from the decomposition reaction means with water. (Please read the precautions on the back before filling out this page)-装 ------- " 丨 Order- -------- Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs