JP2010084181A - Exhaust system structure of film deposition device, film deposition device and method for treating exhaust gas - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust system structure of a film deposition device which can elongate the period of cleaning treatment for removing reaction by-products. <P>SOLUTION: The exhaust system 300 of a film deposition device 100 feeding gaseous TiCl<SB>4</SB>and gaseous NH<SB>3</SB>into a treatment vessel and depositing a TiN film on a substrate W arranged at the inside of the treatment vessel by CVD comprises: an exhaust tube 51 exhausting exhaust gas at the inside of the treatment vessel; a reaction chamber 54 provided at the exhaust tube 51; a water vapor generator 62 and a hydrogen radical generator 64 feeding water vapor and hydrogen radicals and causing reaction of producing the water solution of NH<SB>4</SB>Cl between these and NH<SB>4</SB>Cl and TiCl<SB>x</SB>as by-products produced in the exhaust gas within the reaction chamber 54; and a water solution exhausting mechanism exhausting the water solution of NH<SB>4</SB>Cl from the reaction chamber 54. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an exhaust system structure of a film forming apparatus that forms a predetermined film by CVD, a film forming apparatus having such an exhaust system structure, and an exhaust gas processing method.

  In a semiconductor device manufacturing process, various processes such as a film formation process, a modification process, an oxidation diffusion process, and an etching process are performed on a semiconductor wafer that is a substrate to be processed.

  Among these, as a film forming process, a CVD (Chemical Vapor Deposition) method is often used in which a predetermined processing gas is introduced into a chamber containing a semiconductor wafer and a predetermined film is formed by a chemical reaction. In the CVD method, a process gas is reacted on a semiconductor wafer as a substrate to be processed to form a film. At this time, the process gas that contributes to the reaction is about 10%, and most remains unreacted. .

  Such unreacted processing gas reacts in the chamber or in the course of flowing through the heated exhaust pipe to produce a reaction byproduct, and flows along with the unreacted gas. When an object is cooled, the exhaust pipe is closed or the vacuum pump is damaged. In general, a trap unit is provided in the exhaust pipe extending from the chamber, thereby capturing a by-product.

For example, when a TiN film is formed by using TiCl ₄ gas and NH ₃ gas as raw material gases and reacting them, unreacted TiCl ₄ gas and NH ₃ gas react to form NH ₄ as a by-product. Cl, TiCl _{x and the} like are captured by the trap unit.

In the trap unit, it is desirable to trap in the state of a compound that is easily trapped and has a relatively stable structure. Therefore, a technique has been proposed in which a predetermined reaction gas is added to an exhaust pipe and a desired form of by-product is trapped as a solid in a trap unit (for example, Patent Document 1).
JP 2001-214272 A

  However, even if the by-product is a compound having such a stable structure, a large amount of the by-product adheres to the trap unit as a solid, so that the trap unit is blocked in a relatively short time. For this reason, the trap unit needs to be periodically overhauled, that is, a cleaning process for removing reaction byproducts in a short cycle of about one month. When the TiN film forming apparatus is taken as an example, the downtime of the apparatus per overhaul is 10 hours or more, and as a result, the cost of ownership (CoO) is deteriorated.

  The present invention has been made in view of such circumstances, and an exhaust system structure of a film forming apparatus and such an exhaust system structure, which can lengthen the cycle of a cleaning process for removing reaction byproducts. It is an object of the present invention to provide a film forming apparatus and an exhaust gas treatment method.

  In order to solve the above-mentioned problems, in a first aspect of the present invention, an exhaust system structure of a film forming apparatus that supplies a processing gas into a processing container and forms a film by CVD on a substrate disposed in the processing container. An exhaust pipe for discharging the exhaust gas in the processing vessel, a reaction chamber provided in the exhaust pipe, and a substance that reacts with a by-product generated in the exhaust gas to generate an aqueous solution. An exhaust system structure for a film forming apparatus is provided, comprising: an aqueous solution generation material supply mechanism for causing an aqueous solution generation reaction in the reaction chamber; and an aqueous solution discharge mechanism for discharging the aqueous solution from the reaction chamber.

In a second aspect of the present invention, an exhaust system of a film forming apparatus that forms a TiN film by CVD on a substrate disposed in a processing container by supplying TiCl ₄ gas and NH ₃ gas as processing gases in the processing container. An exhaust pipe for discharging exhaust gas in the processing vessel; a reaction chamber provided in the exhaust pipe; and supplying water vapor and hydrogen radicals, and these are generated in the exhaust gas in the reaction chamber. An aqueous solution generating substance supply mechanism for causing a reaction to generate an aqueous solution of NH ₄ Cl between NH ₄ Cl and TiCl _x as by-products, and an aqueous solution discharge for discharging the aqueous solution of NH ₄ Cl from the reaction chamber An exhaust system structure for a film forming apparatus is provided.

In the second aspect, in the reaction chamber, TiO ₂ can be generated by the reaction of the water vapor, the hydrogen radical, and TiCl _x . The aqueous solution generating substance supply mechanism may include a water vapor generator that generates water vapor and a hydrogen radical generator that generates hydrogen radicals. In this case, the hydrogen radical can be generated by plasma.

  In a third aspect of the present invention, a processing container in which a substrate is disposed, a processing gas supply mechanism that supplies a processing gas into the processing container in which the substrate is disposed, and energy is applied to the processing gas to form the processing gas on the substrate. A film forming apparatus for forming a film on a substrate, comprising: a means for generating a membrane reaction; and an exhaust system structure for exhausting exhaust gas from the processing container and processing the exhaust gas, wherein the exhaust system structure includes An exhaust pipe for exhausting exhaust gas in the processing container; a reaction chamber provided in the exhaust pipe; and a substance that reacts with a by-product generated in the exhaust gas to produce an aqueous solution, The film forming apparatus includes: an aqueous solution generation material supply mechanism that causes an aqueous solution generation reaction; and an aqueous solution discharge mechanism that discharges the aqueous solution from the reaction chamber.

In a fourth aspect of the present invention, a processing container in which a substrate is disposed, a processing gas supply mechanism that supplies TiCl ₄ gas and NH ₃ gas as processing gases in the processing container in which the substrate is disposed, and heating the substrate By forming the TiN film on the substrate, there is provided means for energizing the processing gas to cause a film forming reaction on the substrate and an exhaust system structure for exhausting the exhaust gas from the processing vessel and processing the exhaust gas. The exhaust system structure includes: an exhaust pipe for exhausting exhaust gas in the processing container; a reaction chamber provided in the exhaust pipe; and supplying water vapor and hydrogen radicals to the reaction chamber. in an aqueous solution generating material supply mechanism to cause the reaction to produce an aqueous solution of NH 4 _Cl with the NH 4 _Cl and TiCl _x is a by-product produced in these and the flue gas, before the said reaction chamber To provide a film forming apparatus characterized by comprising an aqueous solution discharge mechanism for discharging an aqueous solution of NH 4 _Cl.

  According to a fifth aspect of the present invention, there is provided an exhaust gas processing method in a film forming apparatus for supplying a processing gas into a processing container and forming a film by CVD on a substrate disposed in the processing container, the processing container A substance that discharges the exhaust gas in the exhaust pipe, supplies a substance that reacts with the by-product generated in the exhaust gas to generate an aqueous solution, and generates the aqueous solution in a reaction chamber provided in the exhaust pipe An exhaust gas treatment method is provided, wherein an aqueous solution generation reaction is caused between the reaction product and the by-product, and the aqueous solution is discharged from the reaction chamber.

In a sixth aspect of the present invention, exhaust gas in a film forming apparatus that supplies TiCl ₄ gas and NH ₃ gas as processing gases into a processing container and forms a TiN film by CVD on a substrate disposed in the processing container. A processing method for exhausting exhaust gas in the processing vessel to an exhaust pipe, supplying water vapor and hydrogen radicals, and by-products generated in the exhaust gas in a reaction chamber provided in the exhaust pipe Provided is an exhaust gas treatment method characterized by causing a reaction to generate an aqueous solution of NH ₄ Cl between NH ₄ Cl and TiCl _{x as} materials, and discharging the aqueous solution of NH ₄ Cl from the reaction chamber To do.

  According to a seventh aspect of the present invention, there is provided a storage medium that operates on a computer and stores a program for controlling the film forming apparatus, wherein the program is executed according to the fifth or sixth aspect. Provided is a storage medium characterized by causing a computer to control the film forming apparatus so that the method is performed.

  According to the present invention, a substance that generates an aqueous solution by reacting with a by-product generated in the exhaust gas flowing through the exhaust pipe is supplied to generate the aqueous solution in a reaction chamber provided in the exhaust pipe. An aqueous solution generating substance supply mechanism that causes an aqueous solution generation reaction between the reaction product and the by-product and an aqueous solution discharge mechanism that discharges the aqueous solution from the reaction chamber are provided, so that the amount of by-products trapped as solids is significantly reduced. And the overhaul cycle can be significantly extended.

In particular, when using a TiN film by CVD using TiCl ₄ gas and NH ₃ as the processing gas, an aqueous solution product introduction mechanism is used to supply water vapor and hydrogen radicals, and these are generated in the exhaust gas in the reaction chamber. It is assumed that a reaction to generate an aqueous solution of NH ₄ Cl occurs between NH ₄ Cl and TiCl _x, which are by-products, and the aqueous solution is discharged from the aqueous solution discharge mechanism, and is trapped as a solid. By-products can be significantly reduced and the overhaul period can be significantly extended. In addition, TiCl _x that causes generation of Cl-based gas in the by-product can be made TiO ₂ harmless to the human body, and the cleaning treatment work for removing the reaction by-product becomes easy.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the present embodiment, a description will be given taking as an example an apparatus for forming a TiN film by CVD on the surface of a semiconductor wafer (hereinafter simply referred to as a wafer) as a substrate to be processed.

  FIG. 1 is a schematic view showing a film forming apparatus having an exhaust system structure according to an embodiment of the present invention. The film forming apparatus 100 is roughly divided into a film forming processing unit 200 and an exhaust system 300.

  The film forming unit 200 includes a substantially cylindrical chamber 11 made of aluminum or an aluminum alloy (for example, JIS A5052). Inside the chamber 11, a susceptor 12 for horizontally supporting a wafer W as a substrate to be processed is disposed in a state of being supported by a cylindrical support member 13 provided at the lower center of the susceptor 12. A heater 14 is embedded in the susceptor 12, and the heater 14 heats the wafer W, which is a substrate to be processed, to a predetermined temperature.

  A shower head 20, which is a gas discharge member, is provided on the upper portion of the chamber 11. The shower head 20 has a disk shape, has a gas diffusion space 21 inside, and has a number of gas discharge holes 22 formed in the lower part. A gas supply port 23 is provided at the upper center.

  A circular hole 31 is formed in the center of the bottom wall of the chamber 11, and an exhaust chamber 32 that protrudes downward is provided on the bottom wall of the chamber 11 so as to cover the hole 31. An exhaust port 33 is formed in the bottom surface of the exhaust chamber 32. A loading / unloading port 35 for loading / unloading the wafer W is formed on the side wall of the chamber 11, and the loading / unloading port 35 can be opened and closed by a gate valve 36.

A processing gas supply system 40 for supplying a processing gas for film formation is connected to the shower head 20 via a pipe 41, and an opening / closing valve 42 is provided in the middle of the pipe 41. The processing gas supply system 40 has a plurality of gas supply sources for supplying a film forming gas such as TiCl ₄ gas, NH ₃ gas, and N ₂ gas and a CF ₃ gas as a cleaning gas. The flow rate is controlled by a flow rate control device such as a mass flow controller and can be supplied into the chamber 11 through the pipe 41 and the shower head 20. In addition, although the piping 41 is represented by one for convenience, actually, it is individually supplied from each gas supply source via piping.

On the other hand, the exhaust system 300 has an exhaust pipe 51 connected to the exhaust port 33. The exhaust pipe 51 is made of stainless steel and has an inner diameter of about 5 to 10 cm. The exhaust pipe 51 includes, in order from the upstream side, an on-off valve 52, a pressure adjustment valve 53, a reaction chamber 54 to which reaction by-products in exhaust gas are guided, a vacuum pump 55 for exhausting the chamber 11, and an exhaust gas An abatement device 56 is provided for completely removing impurities remaining in the substrate. Then, unreacted TiCl ₄ gas and NH ₃ gas in the chamber 11 are exhausted through the exhaust pipe 51 by the vacuum pump 55.

  The pressure regulating valve 53 may be provided between the reaction chamber 54 and the vacuum pump 55 in FIG. As a result, reaction by-products adhering into the pressure regulating valve 53 are reduced, and the maintenance cycle of the pressure regulating valve 53 can be extended.

  A bypass pipe 58 is connected so as to connect an upstream part of the opening / closing valve 42 in the pipe 41 and a part immediately downstream of the pressure regulating valve 53 in the exhaust pipe 51. The bypass pipe 58 is provided with an open / close valve 59. The bypass pipe 58 is for exhausting the processing gas flowing when the gas flow rate is stabilized directly to the exhaust pipe 51 without passing through the chamber 11.

  Tape heaters 81, 82, and 83 are wound around the pipe 41, the bypass pipe 58, and the exhaust pipe 51, respectively, as indicated by broken lines in the figure. The gas component is prevented from condensing.

In the chamber 11 and the exhaust pipe 51, unreacted TiCl ₄ gas and NH ₃ gas react to generate reaction by-products such as NH ₄ Cl and TiCl _x . These by-products flow through the exhaust pipe 51 in a gaseous state by heating by the tape heater 83.

Unreacted TiCl ₄ gas and NH ₃ gas, and reaction byproducts such as NH ₄ Cl and TiCl _x are introduced into the reaction chamber 54 through the exhaust pipe 51. In addition, a water vapor generator 62 is connected to the reaction chamber 54 via a pipe 61, and a hydrogen radical generator 64 is further connected via a waveguide 63. Further, a drainage pipe 57 is connected to the lower part of the side surface of the reaction chamber 54, and an open / close valve 57 a is connected to the drainage pipe 57. In the reaction chamber 54, reaction by-products such as NH ₄ Cl and TiCl _x react with water vapor from the water vapor generator 62 and hydrogen radicals from the hydrogen radical generator 64 to form an aqueous solution of NH ₄ Cl. This aqueous solution is generated and discharged from the drainage pipe 57. The water vapor generator 62 and the hydrogen radical generator 64 function as an aqueous solution product supply mechanism. In the reaction chamber 54, a stable solid by-product such as TiO ₂ is also formed by the reaction. Therefore, the reaction chamber 54 also functions as a trap unit.

  As the water vapor generator 62 and the hydrogen radical generator 64, known ones can be used. Specifically, a water vapor generator (WVG; manufactured by Fujikin Co., Ltd.) or the like can be used as the water vapor generator 62, and a hydrogen radical generator 64 that excites hydrogen by remote plasma is suitable. Can be used. Note that at least one of the water vapor generation mechanism 62 and the hydrogen radical generator 64 may be connected to an upstream portion of the reaction chamber 54 in the exhaust pipe 51.

  The components of the film forming apparatus 100 are connected to and controlled by a process controller 110 made up of a microprocessor (computer). Further, the process controller 110 includes a user interface 111 including a keyboard on which a process manager inputs commands to manage the film forming apparatus 100, a display that visualizes and displays the operation status of the process controller 110, and the like. Is connected. Further, the process controller 110 executes processes on each component of the etching apparatus 100 according to control programs for realizing various processes executed by the film forming apparatus 100 under the control of the process controller 110 and processing conditions. A storage unit 112 in which a program, i.e., a recipe, is stored is connected. The recipe may be stored in a hard disk or a semiconductor memory, or may be set at a predetermined position in the storage unit 112 while being stored in a portable storage medium such as a CDROM or DVD. Furthermore, you may make it transmit a recipe suitably from another apparatus via a dedicated line, for example. Then, if necessary, an arbitrary recipe is called from the storage unit 112 by an instruction from the user interface 111 and is executed by the process controller 110, so that the desired value in the film forming apparatus 100 is controlled under the control of the process controller 110. Is performed.

Next, the processing operation of the film forming apparatus 100 configured as described above will be described.
First, the exhaust system 300 is operated to evacuate the chamber 11, and then the wafer W is loaded into the chamber 11 and placed on the susceptor 12. Then, the wafer W is heated to a predetermined temperature by the heater 14. In this state, TiCl ₄ gas, NH ₃ gas, and N ₂ gas are first supplied to the bypass pipe 58 from the processing gas supply unit 40 at a predetermined flow rate, and preflow is performed. The pressure adjustment valve 53 is operated while being supplied into the chamber 11 through 20, and the inside of the chamber 11 is maintained at a predetermined pressure. In this state, TiCl ₄ gas and NH ₃ gas react on the wafer W placed on the susceptor 12 and maintained at a predetermined temperature, and a TiN film is deposited on the surface of the wafer W.

At this time, TiCl ₄ gas and NH ₃ gas that have not contributed to the film formation are exhausted through the exhaust pipe 51 as exhaust gas. At this time, the processing gas consumed for the reaction out of the TiCl ₄ gas and the NH ₃ gas is about 10%, and most of them remain unreacted. Such an unreacted processing gas flows in the chamber 11 or in the middle of flowing through the exhaust pipe 51, for example, as a by-product by the reaction of the following formula (1) (not considering the valence) as NH ₄ Cl and TiCl _x are mainly produced. These flow through the exhaust pipe 51 in a gaseous state by heating by the tape heater 83 and are led to the reaction chamber 54.
TiCl ₄ + NH ₃ → TiN + NH ₄ Cl (x) + TiCl _x (1)

In the reaction chamber 54, as shown in FIG. 2, most of the processing gas is introduced into the reaction chamber 54 as NH ₄ Cl (x) and TiCl _{x as} byproducts, and unreacted gas is converted into the reaction chamber 54. The above reaction (1) occurs. In addition to the exhaust gas from the exhaust pipe 51, water vapor is introduced from the water vapor generator 62 through the pipe 61 into the reaction chamber 54, and hydrogen radicals are further introduced from the hydrogen radical generator 64 through the waveguide 63. Thereby, in the reaction chamber 54, NH ₄ Cl (x) and TiCl _x as by-products react with each other by the water vapor and the hydrogen radical as in the following formula (2) (without considering the valence). That is, it is re-reacted with water vapor (H ₂ O) to which NH ₄ Cl has been added to form an aqueous solution, and TiClx is converted to TiO ₂ by the added hydrogen radical and water vapor.
TiCl _x + NH ₄ Cl (x) + H ₂ O + H ^* → TiO ₂ + HCl + (NH ₄ ⁺ + Cl ⁻ ) (2)

Then, the NH ₄ Cl aqueous solution is discharged through the drainage pipe 57 by opening the open / close valve 57a. It is treated in a wastewater treatment facility.

Conventionally, as shown in FIG. 3, a trap unit 71 is provided in the exhaust pipe 51, and a gaseous unreacted gas and a gaseous byproduct gas generated by partial reaction are guided to the trap unit 71. By the reaction shown in (1) above, solid NH ₄ Cl (x) and TiCl _x were generated as by-products. Among these, the by-product trapped predominantly is NH ₄ Cl (x), which is considered to be a factor that blocks the trap unit 71 in a short time. In addition, since incomplete TiCl _x is included, a Cl-based gas is generated when the trap unit 71 is overhauled.

On the other hand, in this embodiment, NH ₄ Cl (x), which is a solid by-product that has been dominantly trapped in the trap unit, is made into an aqueous solution and discharged through the drain pipe 57. In the reaction chamber 54 having the function of the conventional trap unit, the amount of the by-product trapped as a solid can be remarkably reduced by using only TiO ₂ . For this reason, the overhaul cycle can be significantly extended. For this reason, cost of ownership (CoO) can be made favorable.

In addition, since TiCl _x which has conventionally been a cause of generation of Cl-based gas has been changed to TiO ₂ that is harmless to the human body, an overhaul (cleaning treatment for removing reaction by-products) is facilitated.

  The remaining exhaust gas after causing the reaction in the reaction chamber 54 as described above is sent to the abatement device 56 via the vacuum pump 55, where the impurity components are completely removed.

The present invention can be variously modified without being limited to the above embodiment. For example, in the above-described embodiment, the case of forming a TiN film using TiCl ₄ gas and NH ₃ gas has been described as an example. However, the present invention is not limited to this and can be applied to various film forming processes. For example, when the present invention is applied when forming a Ti film using TiCl ₄ gas or H ₂ gas, it is the same as the case where the TiN film of the above embodiment is formed.

  In the above-described embodiment, the reaction chamber has a trap function. However, the present invention is not limited to this. For example, a trap may be separately provided at the rear stage of the reaction chamber.

  Moreover, in the said embodiment, although the semiconductor wafer was illustrated as a to-be-processed substrate, it is not restricted to this, Other substrates, such as a glass substrate for flat panel displays (FPD) represented by the liquid crystal display device (LCD), are also shown. Applicable.

The schematic diagram which shows the film-forming apparatus provided with the exhaust system structure which concerns on one Embodiment of this invention. The figure for demonstrating the production | generation substance in the reaction chamber used for the exhaust system of the film-forming apparatus shown in FIG. The figure for demonstrating the production | generation substance in the trap unit used for the exhaust system of the conventional film-forming apparatus.

Explanation of symbols

11; Chamber 12; Susceptor 14; Heater 20; Shower head 32; Exhaust chamber 33; Exhaust port 40; Process gas supply 41; Piping 51; Exhaust tube 54; Reaction chamber 55; Vacuum pump 56; Detoxifying device 58; Bypass Piping 100; Deposition apparatus 200; Deposition processing unit 300; Exhaust system W; Semiconductor wafer

Claims (10)

An exhaust system structure of a film forming apparatus for supplying a processing gas into a processing container and forming a film by CVD on a substrate disposed in the processing container,
An exhaust pipe for exhausting exhaust gas in the processing vessel;
A reaction chamber provided in the exhaust pipe;
An aqueous solution generation material supply mechanism that supplies a substance that reacts with the by-product generated in the exhaust gas to generate an aqueous solution, and causes an aqueous solution generation reaction between the substance and the by-product in the reaction chamber. When,
An exhaust system structure for a film forming apparatus, comprising: an aqueous solution discharge mechanism for discharging the aqueous solution from the reaction chamber. An exhaust system structure of a film forming apparatus for supplying a TiCl ₄ gas and an NH ₃ gas as processing gases into a processing container and forming a TiN film by CVD on a substrate disposed in the processing container,
An exhaust pipe for exhausting exhaust gas in the processing vessel;
A reaction chamber provided in the exhaust pipe;
An aqueous solution that supplies water vapor and hydrogen radicals to cause a reaction in the reaction chamber to generate an aqueous solution of NH ₄ Cl between these and NH ₄ Cl and TiCl _x that are by-products generated in the exhaust gas. A product supply mechanism;
An exhaust system structure for a film forming apparatus, comprising: an aqueous solution discharge mechanism for discharging the aqueous solution of NH ₄ Cl from the reaction chamber. 3. The exhaust system structure of a film forming apparatus according to claim 2, wherein in the reaction chamber, TiO ₂ is generated by a reaction between the water vapor, the hydrogen radical, and TiCl _x .   The exhaust system of the film forming apparatus according to claim 2, wherein the aqueous solution product supply mechanism includes a water vapor generator that generates water vapor and a hydrogen radical generator that generates hydrogen radicals. Construction.   The exhaust system structure of a film forming apparatus according to claim 4, wherein the hydrogen radical is generated by plasma. A processing vessel in which a substrate is placed;
A processing gas supply mechanism for supplying a processing gas into a processing container in which a substrate is disposed;
Means for applying energy to the processing gas to cause a film forming reaction on the substrate;
Exhaust gas is discharged from the processing container, and an exhaust system structure for processing the exhaust gas is provided.
A film forming apparatus for forming a film on a substrate,
The exhaust system structure is
An exhaust pipe for exhausting exhaust gas in the processing vessel;
A reaction chamber provided in the exhaust pipe;
An aqueous solution generating substance supply mechanism for supplying an agent that reacts with a by-product generated in the exhaust gas to generate an aqueous solution and causing an aqueous solution generating reaction in the reaction chamber;
A film forming apparatus comprising an aqueous solution discharge mechanism for discharging the aqueous solution from the reaction chamber. A processing vessel in which a substrate is placed;
A processing gas supply mechanism for supplying TiCl ₄ gas and NH ₃ gas as processing gases into a processing container in which a substrate is disposed;
Means for energizing the processing gas by heating the substrate to cause a film forming reaction on the substrate;
Exhaust gas is discharged from the processing container, and an exhaust system structure for processing the exhaust gas is provided.
A film forming apparatus for forming a TiN film on a substrate,
The exhaust system structure is
An exhaust pipe for exhausting exhaust gas in the processing vessel;
A reaction chamber provided in the exhaust pipe;
An aqueous solution that supplies water vapor and hydrogen radicals to cause a reaction in the reaction chamber to generate an aqueous solution of NH ₄ Cl between these and NH ₄ Cl and TiCl _x that are by-products generated in the exhaust gas. A product supply mechanism;
A film forming apparatus, comprising: an aqueous solution discharge mechanism for discharging the aqueous solution of NH ₄ Cl from the reaction chamber. A method for treating exhaust gas in a film forming apparatus for supplying a processing gas into a processing container and forming a film by CVD on a substrate disposed in the processing container,
Exhaust the exhaust gas in the processing vessel to an exhaust pipe,
A substance that reacts with the by-product generated in the exhaust gas to generate an aqueous solution is supplied, and the aqueous solution is formed between the substance that generates the aqueous solution in the reaction chamber provided in the exhaust pipe and the by-product. Cause a production reaction,
A method for treating exhaust gas, wherein the aqueous solution is discharged from the reaction chamber. An exhaust gas treatment method in a film forming apparatus for supplying TiCl ₄ gas and NH ₃ gas as processing gases into a processing vessel and forming a TiN film on the substrate disposed in the processing vessel by CVD,
Exhaust the exhaust gas in the processing vessel to an exhaust pipe,
An aqueous solution of NH ₄ Cl is supplied between NH ₄ Cl and TiCl _x which are by-products generated in the exhaust gas in a reaction chamber provided in the exhaust pipe by supplying water vapor and hydrogen radicals. Cause the reaction to produce,
An exhaust gas treatment method, wherein the aqueous NH ₄ Cl solution is discharged from the reaction chamber. A storage medium that operates on a computer and stores a program for controlling the film forming apparatus, wherein the program is stored in the computer so that the method of claim 8 or 9 is performed at the time of execution. A storage medium that controls the film forming apparatus.

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