JP2020057715A - Thin film forming apparatus and operating method of the same - Google Patents

Abstract

To provide a thin film forming apparatus capable of preventing corrosion of an exhaust pipe while preventing generation of deposits in the exhaust pipe.SOLUTION: A thin film forming apparatus 1 includes: a reaction furnace 2; a raw material gas supply path L1 for supplying a raw material gas into the reaction furnace 2; a raw gas flow rate control device 3; an exhaust path L4 for conveying an exhaust gas discharged from the reaction furnace 2; and a vacuum pump 6 provided in the exhaust path L4. The exhaust path L4 includes: halogen-containing gas supply paths L5, L6 provided with halogen-containing gas inlets 7, 8, and connected to the halogen-containing gas inlets 7, 8; halogen-containing gas flow rate control devices 9, 10; and a control device 11 electrically connected with the raw gas flow rate control device 3 and the halogen-containing gas flow rate control devices 9, 10.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a thin film forming apparatus and a method for operating the same.

In the manufacture of electronic devices such as semiconductor integrated devices and liquid crystal panels, films of various materials are formed on a substrate by a method such as PVD (physical vapor deposition) or CVD (chemical vapor deposition). You. For example, in a film forming process by the CVD method, various materials such as SiH ₄ , Si (OC ₂ H ₅ ) ₄ (hereinafter, referred to as “TEOS”), WF ₆ (tungsten hexafluoride) are used, An oxide film, a nitride film, or the like is formed on a substrate or the like in the reaction chamber. In such a film forming process, undecomposed materials or by-products are discharged to the downstream side of the reaction chamber, and low-boiling components are deposited particularly at a location where the pressure rises to the atmospheric pressure downstream of the dry pump.

Further, a part of the film forming material is not effectively used for forming a thin film on a substrate or the like, and adheres to an inner wall of a reaction chamber, an electrode surface, or the like. In particular, in a process in which a large amount of deposits are generated, a dry cleaning process of removing a deposit by introducing a reactive gas may be performed for the purpose of maintaining film formation quality. For example, in a silicon nitride film formation CVD using SiH ₄ and NH ₃ or a silicon oxide film formation CVD using TEOS and O ₂ , a dry cleaning process using a fluorine-based gas such as NF ₃ or perfluorocarbon is often performed. In such a dry cleaning process, undecomposed materials or by-products are discharged downstream of the reaction chamber, and deposition of low-boiling components occurs particularly at a point where the pressure rises to the atmospheric pressure downstream of the dry pump.

As described above, reaction by-products deposited on the inner wall surface of the exhaust pipe include silicon oxide, silicon oxynitride, and ammonium silicofluoride (alias: ammonium hexafluorosilicate; chemical formula: SiF ₆ (NH ₄ ) ₂ ). ) And various silicon compounds. These deposits can cause serious troubles such as clogging of exhaust pipes. For this reason, it is indispensable to take appropriate measures such as removing the exhaust pipe, cleaning and then reusing or replacing the exhaust pipe. In order to perform such maintenance work, it is necessary to stop the apparatus, and there is a problem that not only the effect on the productivity but also the overload on the dry pump due to the stop / restart occurs.

  As a solution to such a problem, Patent Literature 1 and Patent Literature 2 disclose a method of heating an exhaust pipe between a semiconductor manufacturing device and an exhaust gas treatment device to suppress the adhesion of deposits. . In particular, Patent Literature 2 describes that all of the exhaust pipes are continuously heated to 120 to 160 ° C.

In recent years, thin film formation at a lower temperature than in the past has been required. Accordingly, film forming materials having lower vapor pressure and higher reactivity than in the past have been widely used. Specifically, SiH (N (CH ₃ ) ₂ ) ₃ (hereinafter referred to as 3DMAS), SiH ₂ (N (C ₂ H ₅ ) ₂ ) ₂ (hereinafter referred to as BDEAS), SiH ₂ (NH (C ₃ H _{7)) 2} (hereinafter, referred to as DIPAS) such as a film-forming material is a liquid at room temperature. The heating of the exhaust pipe described in Patent Document 1 and Patent Document 2 described above suppresses the undecomposed components of these low vapor pressure materials from adsorbing on the exhaust pipe. However, on the other hand, there is a problem that the reaction between the low vapor pressure material and oxygen or moisture, that is, the generation of a silicon compound such as silicon oxide is promoted.

  As a solution to such a problem, Patent Literature 3 and Patent Literature 4 disclose a method in which a fluorine-containing interhalogen gas is introduced into an exhaust pipe to remove a deposit by reaction. However, since this is an independent process from the film forming process, there is a problem that excessively high reactive gas is introduced to cause corrosion of the exhaust pipe.

Japanese Patent No. 4210395 JP 2011-058033 A JP 2001-189277 A Japanese Patent No. 3007032

  The present invention has been made in view of the above circumstances, and provides a thin film forming apparatus capable of preventing generation of deposits in an exhaust pipe and preventing corrosion of the exhaust pipe, and an operation method thereof. As an issue.

In order to solve the above problems, the present invention has the following configurations.
[1] a reactor for forming a thin film;
One or more source gas supply paths for supplying a source gas into the reactor;
One or more source gas flow control devices provided in the source gas supply path,
An exhaust path for transporting exhaust gas discharged from the reactor,
A vacuum pump provided in the exhaust path,
One or more halogen-containing gas inlets provided in the exhaust path;
One or more halogen-containing gas supply paths for supplying a halogen-containing gas from the halogen-containing gas inlet into the exhaust path;
One or more halogen-containing gas flow control devices provided in the halogen-containing gas supply path;
A thin film forming apparatus comprising: at least one of the raw material gas flow control device and a control device electrically connected to the halogen-containing gas flow control device.
[2] The thin film forming apparatus according to [1], wherein the exhaust path has at least one or more of the halogen-containing gas inlets on a secondary side of the vacuum pump.
[3] The thin-film forming apparatus according to [1] or [2], wherein the exhaust path has at least one or more of the halogen-containing gas inlets on a primary side of the vacuum pump.
[4] The thin-film forming apparatus according to any one of [1] to [3], wherein the source gas contains at least one metal atom of silicon and germanium.
[5] The thin film forming apparatus according to any one of [1] to [4], wherein the halogen-containing gas contains a fluorine atom.
[6] The control device calculates the integrated supply number A of the metal atoms contained in the source gas, and calculates the integrated supply number B of the halogen atoms contained in the halogen-containing gas. The thin film forming apparatus according to [4] or [5], wherein the supply time of the halogen-containing gas is calculated so as to be in a range of 3 to 5 times.
[7] A method for operating the thin film forming apparatus according to any one of [1] to [6],
An operation method of a thin film forming apparatus, wherein the halogen-containing gas is supplied into the exhaust path only while a component reacting with the halogen-containing gas is present in the exhaust path.
[8] The operation method of the thin film forming apparatus according to [7], wherein a supply time of the halogen-containing gas into the exhaust path is calculated from a supply amount of the raw material gas supplied into the reaction furnace.
[9] The source gas contains at least one or more metal atoms of silicon and germanium,
When the halogen-containing gas contains a fluorine atom,
The thin-film formation according to [8], wherein the supply time of the halogen-containing gas is controlled such that the cumulative number of supplied atoms B of the fluorine atoms is in a range of 3 to 5 times the cumulative number of supplied atoms A of the metal atoms. How to operate the device.

  ADVANTAGE OF THE INVENTION The thin film formation apparatus of this invention and its operating method can prevent generation | occurrence | production of the deposit in an exhaust pipe, and can also prevent corrosion of an exhaust pipe.

1 is a system diagram illustrating a configuration of a thin film forming apparatus according to an embodiment to which the present invention is applied. FIG. 3 is a diagram illustrating timings of supplying a source gas and a halogen-containing gas in the first embodiment. FIG. 9 is a diagram illustrating supply timings of a source gas and a halogen-containing gas in a second embodiment. FIG. 11 is a diagram illustrating supply timings of a source gas and a halogen-containing gas in a third embodiment.

  Hereinafter, a thin film forming apparatus according to an embodiment to which the present invention is applied will be described in detail together with an operation method thereof with reference to the drawings. In addition, in the drawings used in the following description, in order to make the characteristics easy to understand, the characteristic portions may be enlarged for convenience, and the dimensional ratios and the like of the respective components are not necessarily the same as the actual ones. Absent.

<Thin film forming equipment>
First, the configuration of a thin film forming apparatus according to an embodiment of the present invention will be described. FIG. 1 is a system diagram schematically illustrating an example of the configuration of a thin film forming apparatus according to an embodiment of the present invention.
As shown in FIG. 1, a thin film forming apparatus 1 of the present embodiment includes a reaction furnace 2, a source gas supply path L1, a source gas flow control device 3, an exhaust path L4, a vacuum pump 6, and halogen-containing gas inlets 7, 8. , A halogen-containing gas supply path L5, L6, a halogen-containing gas flow rate control device 9, 10, and a control device 11. The thin film forming apparatus 1 of the present embodiment is an apparatus for keeping the inside of the exhaust path L4 clean.

  The thin film forming apparatus 1 of the present embodiment is not particularly limited as long as it is an apparatus that forms a thin film on the surface of an object such as a substrate. Examples of the thin film forming apparatus 1 include a plasma CVD (plasma-enhanced chemical vapor deposition) apparatus, a thermal CVD apparatus, and an atomic layer deposition (ALD) apparatus.

The reaction furnace 2 accommodates a substrate (for example, a silicon substrate) to be an object in an inner space and forms a thin film such as an oxide film, a nitride film, and a metal thin film on the surface of the object. .
The reactor 2 is connected to one or more source gas supply paths L1, various process gas supply paths L2, and inert gas supply paths L3. Thus, the raw material gas, various process gases, and the inert gas can be appropriately supplied into the reaction furnace 2.
Further, an exhaust path L4 is connected to the reaction furnace 2. Thereby, the exhaust gas in the reactor 2 can be discharged to the outside of the reactor 2.

  The source gas supply path L <b> 1 is a supply pipe provided to supply the source gas into the reaction furnace 2. The source gas is not particularly limited, but preferably contains at least one metal atom among silicon and germanium, and more preferably contains silicon.

Examples of the source gas containing silicon include SiH ₄ , Si ₂ H ₆ , Si ₃ H ₈ , TEOS, 3DMAS, BDEAS, DiPAS, and the like.
As a source gas containing germanium, GeH ₄ , Ge ₂ H ₆ , Ge (CH ₃ ) ₄ , Ge (C ₂ H ₅ ) ₄ , ((CH ₃ ) ₂ CHCH ₂ ) GeH ₃ , (isobutylgermane / IBGe) And the like.

  The material of the source gas supply path (supply pipe) L1 is not particularly limited as long as it is not corroded by the source gas. Examples of such a material include metals such as stainless steel and titanium, and resins such as vinyl chloride.

  The number of the raw material gas supply paths L1 is not particularly limited, and can be appropriately selected according to the type of the raw material supplied into the reactor 2.

  The source gas flow control device 3 is a device provided in the source gas supply path L1 for measuring and controlling the flow rate of the source gas flowing in the source gas supply path L1. As the raw material gas flow control device 3, a commercially available mass flow controller (MFC) can be used.

  The source gas flow controller 3 is electrically connected to the controller 11. That is, the raw material gas flow control device 3 and the control device 11 can transmit and receive signals to and from each other by a wired or wireless signal. Specifically, the raw material gas flow control device 3 transmits the flow rate and the supply time of the raw material gas supplied into the reaction furnace 2 through the raw material gas supply path L1 to the control device 11, and the control device 11 The control signal of the source gas flow control device 3 can be received.

  The material and number of the process gas supply path L2 and the inert gas supply path L3 can be the same as those of the above-described source gas supply path L1. Further, flow control devices 4 and 5 are provided in the process gas supply path L2 and the inert gas supply path L3, respectively. As the flow control devices 4 and 5, a commercially available mass flow controller can be used similarly to the raw material gas flow control device 3.

The exhaust path L4 is an exhaust pipe provided to transport exhaust gas discharged from the inside of the reaction furnace 2 to an exhaust gas processing device (not shown). In other words, the exhaust path L4 is an exhaust pipe provided between the reaction furnace 2 and an exhaust gas treatment device (not shown).
The exhaust gas passing through the exhaust gas path L4 includes various gases supplied into the reaction furnace 2, that is, unreacted raw material gas, various process gases, and inert gases, and a reaction gas generated in the reaction furnace 2. Reaction by-product gas.
Further, a vacuum pump 6 and halogen-containing gas inlets 7 and 8 are provided in the exhaust path L4.

  The material of the exhaust path (exhaust pipe) L4 is not particularly limited as long as the exhaust gas can be led to the abatement apparatus without leaking to the surrounding environment. Examples of such a material include metals such as stainless steel and titanium, and resins such as vinyl chloride. Among them, stainless steel is preferable from the viewpoint of corrosion resistance. Further, an inner surface coating capable of improving corrosion resistance to halogen gas may be applied.

  The vacuum pump 6 is provided in the exhaust path L4. The inside of the reaction furnace 2 can be evacuated by operating the vacuum pump 6 to evacuate the inside of the reaction furnace 2. The specification of the vacuum pump 6 is not particularly limited, and can be appropriately selected depending on the volume of the reaction furnace 2, the flow rate of the gas introduced into the reaction furnace 2, the pressure condition of the process, and the like. As the vacuum pump 6, an EV-M series manufactured by EBARA CORPORATION, an SDE series manufactured by Kashiyama Kogyo, or the like can be used. The vacuum pump 6 may be connected to an inert gas supply path (inert gas supply pipe) L7.

  The halogen-containing gas inlets 7 and 8 are inlets (also referred to as openings and junctions) provided to supply the halogen-containing gas into the exhaust path L4. By supplying the halogen-containing gas from the halogen-containing gas inlets 7 and 8 into the exhaust path L4, the halogen-containing gas can react with the unreacted raw material gas and the like in the exhaust path L4.

  The halogen-containing gas inlet 7 is provided in an exhaust path L4 on the secondary side of the vacuum pump 6. Here, in the evacuation path L, the pressure on the secondary side of the vacuum pump 6 increases, so that more deposits are likely to be generated. By providing the halogen-containing gas inlet 7 at this location, the generation of deposits in the exhaust pipe can be more effectively prevented.

  The halogen-containing gas inlet 8 is provided in the exhaust path L4 on the primary side of the vacuum pump 6. By providing the halogen-containing gas inlet 8 on the primary side of the vacuum pump 6 (that is, on the outlet side of the reaction furnace 2), it is possible to prevent the generation of deposits in the vacuum pump 6.

  In the thin film forming apparatus 1 of the present embodiment, the configuration in which one halogen-containing gas inlet port 7 and 8 are provided in the exhaust path L4 on the primary side and the secondary side of the vacuum pump 6 has been described as an example. However, the present invention is not limited to this. If the exhaust path L4 is provided with at least one or more halogen-containing gas inlets, the effects of the present invention can be achieved. In the exhaust path L4, two or more halogen-containing gas inlets may be provided only on the secondary side of the vacuum pump 6, or two or more halogen-containing gas inlets may be provided only on the primary side of the vacuum pump 6. May be provided. Among these, it is preferable to provide one or more halogen-containing gas inlets on the primary side and the secondary side of the vacuum pump 6, respectively.

  The halogen-containing gas supply path L5 is a supply pipe provided to supply a halogen-containing gas from a halogen-containing gas supply source (not shown) into the exhaust path L4. The halogen-containing gas supply path L5 is provided between a halogen-containing gas supply source (not shown) and the exhaust path L4. Specifically, the halogen-containing gas supply path L5 is connected to the exhaust path L4 at the halogen-containing gas inlet 7.

  Although the halogen-containing gas is not particularly limited, a gas containing at least one or more of fluorine, chlorine, bromine, and iodine is preferable, and a gas containing fluorine is more preferable.

Examples of the halogen-containing gas containing fluorine include hydrogen fluoride (HF), fluorine (F ₂ ), carbonyl difluoride (COF ₂ ), and chlorine trifluoride (CLF ₃ ).

  The combination of the source gas and the halogen-containing gas applied to the present embodiment is not particularly limited. As the combination of the source gas and the halogen-containing gas, it is preferable to use a combination that does not generate a solid component that becomes a deposit when reacted in the exhaust path L4. Specifically, when a gas containing silicon or germanium is used as a source gas, it is preferable to use a gas containing fluorine as a halogen-containing gas, and when a gas containing aluminum or gallium is used as a source gas, It is preferable to use a gas containing chlorine as the contained gas.

  The material of the halogen-containing gas supply path (supply pipe) L5 is not particularly limited as long as it is not corroded by the halogen-containing gas. Examples of such a material include metals such as stainless steel and titanium, and resins such as vinyl chloride.

  The halogen-containing gas flow controller 9 is a device provided in the halogen-containing gas supply path L5 for measuring and controlling the flow rate of the halogen-containing gas flowing in the halogen-containing gas supply path L5. As the halogen-containing gas flow control device 9, a commercially available mass flow controller (MFC) can be used.

  The halogen-containing gas flow control device 9 is electrically connected to the control device 11. That is, the halogen-containing gas flow rate control device 9 and the control device 11 can transmit and receive signals to and from each other by wired or wireless signals. Specifically, the halogen-containing gas flow rate control device 9 transmits the flow rate and the supply time of the halogen-containing gas supplied into the exhaust path L4 via the halogen-containing gas supply path L5 to the control device 11, and controls the control device. From 11, a control signal of the halogen-containing gas flow rate control device 9 can be received.

  The material of the halogen-containing gas supply path L6 can be the same as that of the halogen-containing gas supply path L5 described above. Further, a halogen-containing gas flow control device 10 is provided in the halogen-containing gas supply path L6. As the halogen-containing gas flow control device 10, a commercially available mass flow controller can be used in the same manner as the halogen-containing gas flow control device 9.

  The number of halogen-containing gas supply paths is not particularly limited, and can be appropriately selected according to the number of halogen-containing gas introduction ports (two in the present embodiment) provided in the exhaust path L4. .

  The control device 11 is electrically connected to the raw material gas flow control device 3 and the halogen-containing gas flow control devices 9 and 10. Thereby, the control device 11 transmits the signal of “the flow rate of the raw material gas supplied into the reaction furnace 2” transmitted from the raw material gas flow control device 3 and “the flow rate of the halogen-containing gas flow control devices 9 and 10”. Signal of the flow rate of the halogen-containing gas supplied into the exhaust path L4 ", and transmit control signals to the raw material gas flow control device 3 and the halogen-containing gas flow control devices 9 and 10, respectively. it can.

<Operation method of thin film forming device>
Next, an operation method of the thin film forming apparatus 1 of the present embodiment, that is, a method of forming a thin film and a method of cleaning the inside of the exhaust pipe L4 will be described. In the operation method of the thin film forming apparatus 1 of the present embodiment, a case where the thin film forming apparatus 1 is an ALD apparatus will be described as an example.

(Method of forming thin film)
First, a method for forming a thin film will be described.
A substrate (eg, a silicon substrate) on which a thin film is to be formed is placed in the reaction furnace 2. Next, the inside of the reaction furnace 2 is purged using the inert gas supply path L3 and the vacuum pump 6. Next, a raw material gas and a reactive gas (process gas) composed of an oxidizing gas or a reducing gas are alternately supplied into the reaction furnace 2 to form a thin film on the substrate.

  When a thin film having a desired thickness is formed on the substrate, the substrate in the reaction furnace 2 is replaced, and a thin film forming process is performed. When a thin film is formed, by-products are deposited on portions other than the substrate in the reaction furnace 2. Therefore, the inside of the reaction furnace 2 is appropriately cleaned.

  In general, in the ALD method, after the source gas is supplied into the reaction furnace 2, the source gas floating in the gas phase without being adsorbed on the surface of the substrate is discharged. (Exhaust pipe) Leaded out into L4. After that, the reactive gas is supplied into the reaction furnace 2, but not all of the gas is consumed in the reaction furnace, but is discharged into the exhaust path L <b> 4. Therefore, a reaction occurs in the exhaust path L4, and deposits are generated in the exhaust pipe. In addition, when blockage of the exhaust pipe starts due to the deposit, the generation of the deposit is accelerated at an accelerated rate.

(How to clean the exhaust pipe)
Therefore, in the operation method of the thin film forming apparatus 1 of the present embodiment, the halogen-containing gas is supplied to the exhaust side of the reaction furnace 2 (that is, in the exhaust path L4) in conjunction with the supply of the raw material gas into the reaction furnace 2. To prevent sediment generation. On the other hand, it is also important to prevent exhaust pipe corrosion. Therefore, according to the method of operating the thin film forming apparatus 1 of the present embodiment, only when components (such as deposits and unreacted raw material gas) that react with the halogen-containing gas are present in the exhaust path L4, Is supplied with a halogen-containing gas.

Specifically, the control device 11 controls the halogen-containing gas flow rate control devices 9 and 10 as follows.
(1) After a predetermined waiting time has elapsed from the start of the supply of the source gas into the reaction furnace 2, the supply of the halogen-containing gas into the exhaust path L4 is started.
(2) The integrated supply number of metal atoms contained in the source gas is calculated, and the supply time of the halogen-containing gas into the exhaust path L4 is introduced based on the calculation result and the supply flow rate of the halogen-containing gas. It is determined for each of the ports 7 and 8, and controls the operation of the halogen-containing gas flow rate control devices 9 and 10.

  Here, when the source gas contains at least one or more metal atoms of silicon and germanium, and the halogen-containing gas contains fluorine atoms, the control device 11 determines that the integrated supply number B of fluorine atoms is equal to the number of metal atoms. The supply time of the halogen-containing gas is determined so as to be within the range of 3 to 5 times the cumulative supply atom number A, and the operation of the halogen-containing gas flow controllers 9 and 10 is controlled. By setting the integrated supply atom number B within the range of 3 to 5 times the integrated supply atom number A, it is possible to prevent deposits from being generated in the exhaust path (exhaust pipe) L4 and to prevent corrosion of the exhaust pipe. be able to.

  In the thin film forming apparatus 1 of this embodiment, the halogen-containing gas inlets 7 and 8 are provided on the primary side (upstream side) and the secondary side (downstream side) of the vacuum pump 6, respectively. It is desirable not to introduce a halogen-containing gas from the inlet 8. This can prevent the halogen-containing gas supplied into the exhaust path L4 from back-diffusing to the reaction furnace 2 side.

  As described above, the thin film forming apparatus 1 of the present embodiment and the method of operating the same can prevent the generation of deposits in the exhaust path (exhaust pipe) L4 and also prevent corrosion of the exhaust pipe. Therefore, the maintenance frequency of the thin film forming apparatus 1 can be reduced, and the operation rate of the thin film forming apparatus 1 can be improved.

  Note that the technical scope of the present invention is not limited to the above embodiment, and various changes can be made without departing from the spirit of the present invention. For example, in the thin film forming apparatus 1 of the above-described embodiment, the case where only one type of source gas is introduced into the reaction furnace 2 has been described as an example, but the present invention is not limited to this. By providing a flow control device in each of the supply paths, two or more types of source gases may be used.

  Further, a halogen-containing gas supplied from the halogen-containing gas inlet port 7 provided on the secondary side of the vacuum pump 6 into the exhaust path L4 and an exhaust gas from the halogen-containing gas inlet port 8 provided on the primary side of the vacuum pump 6 are exhausted. The halogen-containing gas supplied into the path L4 may be the same type or a different type. In addition, even if they are the same species, the concentrations may be different.

Hereinafter, the effects of the present invention will be described in detail using examples. In addition, this invention is not limited at all by the following Examples.
The following Examples 1 to 3 were performed using an ALD apparatus having the same configuration as the thin film forming apparatus 1 shown in FIG.

(Example 1)
In the ALD apparatus, a silicon oxide film was formed using trisdimethylaminosilane (3DMAS) as a source gas. Further, hydrogen fluoride (HF) was supplied as a halogen-containing gas from a halogen-containing gas inlet port 7 provided on the downstream side of the vacuum pump 6, and the exhaust pipe was cleaned.
The supply flow rate of 3DMAS was 10 sccm, and the supply flow rate of HF was 40 sccm.
The standby time from the start of supply of 3DMAS to the start of supply of HF was 1 second.

  FIG. 2 is a diagram illustrating supply timings of the source gas and the halogen-containing gas in the first embodiment. In FIG. 2, the upper part shows a graph of the source gas, and the lower part shows a graph of the halogen-containing gas. In FIG. 2, the X-axis indicates the time from the start of film formation, and the Y-axis indicates the supply amount.

As shown in FIG. 2, the supply form of 3DMAS as the source gas was such that supply for 2 seconds and stop for 2 seconds were repeated. Here, the number of Si atoms contained in one 3DMAS molecule is one, and the number of F atoms contained in one HF molecule is one, and the HF flow rate is four times the 3DMAS flow rate. The supply mode was also a two-second supply and a two-second stop.
As a result, SiF ₄ could be efficiently produced as a by-product in the exhaust path (exhaust pipe) L4, and the generation of silicon-containing deposits in the exhaust path L4 could be prevented. Further, no corrosion was observed in the exhaust pipe after repeating the ALD step of this process for 100 hours.

(Example 2)
In the ALD apparatus, a silicon oxide film was formed using trisdimethylaminosilane (3DMAS) as a source gas. Further, chlorine trifluoride (CLF ₃ ) was supplied as a halogen-containing gas from a halogen-containing gas inlet port 7 provided on the downstream side of the vacuum pump 6 to clean the exhaust pipe.
The supply flow rates of 3DMAS and chlorine trifluoride were each 5 sccm.

  FIG. 3 is a diagram illustrating supply timings of the source gas and the halogen-containing gas in the second embodiment. In FIG. 3, the upper graph shows the graph of the source gas, and the lower graph shows the graph of the halogen-containing gas. In FIG. 3, the X-axis indicates the time from the start of film formation, and the Y-axis indicates the supply amount.

As shown in FIG. 3, in the supply form of 3DMAS as the source gas, the supply of 2 seconds and the stop of 2 seconds were repeated 30 times (in the figure, three times). Here, since one 3DMAS molecule contains one Si atom and three CLF molecules contains _three F atoms, and the CLF ₃ flow rate and the 3DMAS flow rate are the same, the halogen-containing gas is used. CLF ₃ was supplied for 80 seconds (= 2 seconds × 30 times × 4 times ÷ 3) after the supply of the source gas was stopped.
As a result, SiF ₄ could be efficiently produced as a by-product in the exhaust path (exhaust pipe) L4, and the generation of silicon-containing deposits in the exhaust path L4 could be prevented. Further, no corrosion was observed in the exhaust pipe after repeating the ALD step of this process for 100 hours.

(Example 3)
In the ALD apparatus, a silicon oxide film was formed using bisdiethylaminosilane (BDEAS) as a source gas. Hydrogen fluoride (HF) is supplied as a halogen-containing gas from a halogen-containing gas inlet port 7 provided on the downstream side of the vacuum pump 6 and a halogen-containing gas inlet port 8 provided on the upstream side of the vacuum pump 6, respectively. The exhaust pipe was cleaned.
The supply flow rate of BDEAS was 20 sccm, and the supply flow rates of HF from the halogen-containing gas inlets 7 and 8 were 10 sccm and 40 sccm, respectively.

  FIG. 4 is a diagram illustrating the timing of supplying the source gas and the halogen-containing gas in the third embodiment. In FIG. 4, the upper graph shows the source gas, the middle graph shows the halogen-containing gas from the halogen-containing gas inlet 7, and the lower graph shows the halogen-containing gas from the halogen-containing gas inlet 8. In FIG. 4, the X axis indicates the time from the start of film formation, and the Y axis indicates the supply amount.

As shown in FIG. 4, in the supply mode of the source gas BDEAS, the supply of 2 seconds and the stop of the supply of 2 seconds were repeated 30 times (in the figure, three times). Thereafter, after a standby time of 120 seconds, the supply of 2 seconds and the stop of 2 seconds were repeated 30 times (in the figure, three times).
The supply form of HF, which is a halogen-containing gas, is such that a standby time from the start of supply of BDEAS to the start of supply of HF from the halogen-containing gas inlet port 7 provided on the downstream side of the vacuum pump 6 is 1 second, and thereafter, 480 seconds continuously.
On the other hand, the raw material gas was supplied from the halogen-containing gas inlet 8 provided on the upstream side of the vacuum pump 6 for 60 seconds during each of the two standby times in which the supply of the raw material gas was stopped.
As a result, SiF ₄ could be efficiently produced as a by-product in the exhaust path (exhaust pipe) L4, and the generation of silicon-containing deposits in the exhaust path L4 could be prevented. Also, corrosion of the exhaust pipe was prevented. Furthermore, during the supply of the raw material gas, the supply of the halogen-containing gas from the halogen-containing gas inlet 8 provided on the upstream side of the vacuum pump 6 was stopped, so that the back-diffusion of the halogen-containing gas into the reaction furnace 2 could be prevented. did it.

  The thin film forming apparatus of the present invention is an exhaust gas of a thin film forming apparatus using a physical vapor deposition method (PVD method) or a chemical vapor deposition method (CVD method) used in the manufacture of semiconductor integrated devices, liquid crystal panels, etc. Has applicability to devices that process

  DESCRIPTION OF SYMBOLS 1 ... Thin film forming apparatus, 2 ... Reactor, 3 ... Raw material gas flow control device, 4, 5 ... Flow control device, 6 ... Vacuum pump, 7, 8 ... Halogen containing gas inlet port, 9, 10 ... Halogen containing gas flow rate Control device, 11: control device, L1: source gas supply path, L2: various process gas supply paths, L3: inert gas supply path, L4: exhaust path (exhaust pipe), L5, L6: halogen-containing gas supply path, L7: inert gas supply path

Claims (9)

A reactor for forming a thin film;
One or more source gas supply paths for supplying a source gas into the reactor;
One or more source gas flow control devices provided in the source gas supply path,
An exhaust path for transporting exhaust gas discharged from the reactor,
A vacuum pump provided in the exhaust path,
One or more halogen-containing gas inlets provided in the exhaust path;
One or more halogen-containing gas supply paths for supplying a halogen-containing gas from the halogen-containing gas inlet into the exhaust path;
One or more halogen-containing gas flow control devices provided in the halogen-containing gas supply path;
A thin film forming apparatus comprising: at least one of the raw material gas flow control device and a control device electrically connected to the halogen-containing gas flow control device.   The thin film forming apparatus according to claim 1, wherein the exhaust path has at least one or more of the halogen-containing gas introduction ports on a secondary side of the vacuum pump.   3. The thin film forming apparatus according to claim 1, wherein the exhaust path has at least one or more of the halogen-containing gas inlets on a primary side of the vacuum pump. 4.   4. The thin film forming apparatus according to claim 1, wherein the source gas includes at least one or more metal atoms of silicon and germanium. 5.   The thin-film forming apparatus according to claim 1, wherein the halogen-containing gas includes a fluorine atom.   The controller calculates the integrated supply number A of the metal atoms contained in the source gas, and the integrated supply number B of the halogen atoms contained in the halogen-containing gas is 3 to 3 of the integrated supply number A. The thin film forming apparatus according to claim 4, wherein the supply time of the halogen-containing gas is calculated so as to be five times as large. An operation method of the thin film forming apparatus according to claim 1, wherein:
An operation method of a thin film forming apparatus, wherein the halogen-containing gas is supplied into the exhaust path only while a component reacting with the halogen-containing gas is present in the exhaust path.   The method according to claim 7, wherein a supply time of the halogen-containing gas into the exhaust path is calculated from a supply amount of the raw material gas supplied into the reaction furnace. The source gas contains at least one or more metal atoms of silicon and germanium,
When the halogen-containing gas contains a fluorine atom,
The thin film formation according to claim 8, wherein the supply time of the halogen-containing gas is controlled such that the cumulative supply number B of the fluorine atoms is in a range of 3 to 5 times the cumulative supply number A of the metal atoms. How to operate the device.

Images