JP2015073020A - Atomic layer deposition device and atomic layer deposition method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a thin film with uniform film thickness and excellent film quality on a substrate.SOLUTION: An atomic layer deposition device for forming a thin film composed of an atomic layer on a substrate comprises: a deposition container in which the substrate is arranged in the inside thereof; a material gas supply unit which adsorbs a material gas generated by the vaporization of a liquid material which is a raw material of the thin film to the substrate by supplying the mixture of the material gas and a carrier gas to the deposition container; and a reaction gas supply unit which supplies a reaction gas which forms an atomic layer by reaction with components of the material gas adsorbed to the substrate. The material gas supply unit comprises: a material tank in which the liquid material is stored and the material gas is generated by the vaporization of the liquid material; a carrier gas supply unit which mixes the material gas and the carrier gas in the material tank by supplying the carrier gas to the material tank; and a storage tank in which the mixture of the material gas and the carrier gas to be supplied to the deposition container is stored at a pressure lower than the material tank and higher than the deposition container.

Description

  The present invention relates to an atomic layer deposition apparatus and an atomic layer deposition method for forming a thin film on a substrate.

  Atomic layer deposition (ALD) is known as a technique for forming a thin film uniformly with excellent step coverage. In the ALD method, two types of gas (raw material gas and reaction gas) mainly containing elements constituting a thin film to be formed are alternately supplied onto the substrate, and the thin film is formed on the substrate in units of atomic layers. In the ALD method, a self-stopping action of the surface reaction is used. The self-stopping action of the surface reaction is an action in which only one layer or several layers of source gas are adsorbed on the substrate surface while the source gas is supplied, and the excess source gas does not contribute to film formation. Therefore, a thin film having a desired film thickness can be formed by repeatedly forming a thin film on the substrate in atomic layer units using the ALD method.

Compared with a general CVD (Chemical Vapor Deposition) method, the ALD method is excellent in step coverage and film thickness controllability. Therefore, the ALD method is used for forming a capacitor of a memory element and an insulating film called a “high-k gate”.
In the ALD method, the insulating film can be formed at a temperature of 300 ° C. or lower. Therefore, in a display device using a glass substrate such as a liquid crystal display, an ALD method is used for forming a gate insulating film of a thin film transistor.

  Incidentally, in recent years, it has been required to form a thin film on a large-area substrate from the viewpoint of production efficiency. When the area of the substrate is increased, it is necessary to increase the volume of the film forming container for storing the substrate. Moreover, it is necessary to increase the supply amount of the raw material gas used as a thin film raw material.

  In the ALD method, a valve for supplying a source gas is opened in a pulsed manner and discharged into a film formation container in a reduced pressure atmosphere. When using a liquid raw material, gasify with a vaporizer. A thin film is formed using this source gas.

  In an atomic layer deposition apparatus in which supply of gas is difficult or an atomic layer deposition apparatus in which a large amount of raw material needs to be supplied, there is a liquid injection valve supply method to control the supply amount of the raw material to the film formation container. In this method, the liquid injection valve is opened for a certain period of time, and the liquid raw material is supplied to the injector in the front stage of the film forming container, and the liquid raw material is vaporized in the injector to become a raw material gas (Patent Document 1).

JP 2012-167317 A

  However, in the method in which the liquid material is vaporized by the injector in front of the film forming container, the injection valve is opened with a pulse of 1 second or less, and the liquid material is supplied to the injector. There is a problem that the supply amount of the raw material is increased from a predetermined supply amount. This is because a liquid has a larger amount of material per volume than that of a gas. When the supply amount of the liquid raw material increases beyond the predetermined supply amount, the liquid raw material is insufficiently vaporized inside the injector, and the raw material is present in the injector in a liquid state. When the raw material is present in the injector in a liquid state, it is difficult to immediately exhaust the raw material, so that the remaining raw material reacts violently with the reaction gas, contaminating the inside of the injector and generating particles.

  Therefore, in order to supply the raw material stably and without condensing, it is desirable to vaporize the liquid raw material with a vaporizer and supply the gaseous raw material gas to the injector. However, when only the vaporized source gas is supplied to the film formation container, the supply amount of the source gas to the film formation container depends on the vapor pressure of the source gas, so that a sufficient supply amount may not be obtained. If heating is performed to increase the vapor pressure of the raw material gas, thermal decomposition of the raw material may occur and the piping and valves may be contaminated.

Further, when the volume of the film formation container is increased, the temperature drop of the source gas due to adiabatic expansion becomes remarkable, and the source gas is liable to be liquefied. When the source gas is liquefied in the film formation container, liquid source liquid droplets adhere to the inner wall of the film formation container, and there is a risk that powder serving as a particle source may be generated in the film formation container, resulting in a deterioration in film quality. There is.
On the other hand, if the raw material gas is heated to prevent the temperature of the raw material gas from being lowered, the raw material may be thermally decomposed and the piping and valves may be contaminated.

  An object of the present invention is to form a thin film having a uniform film thickness and good film quality on a substrate.

In order to solve the above problems, a first aspect of the present invention is an atomic layer deposition apparatus for forming a thin film comprising an atomic layer on a substrate,
A film forming container having a substrate disposed therein;
A raw material gas supply unit for supplying a mixed gas obtained by mixing a raw material gas obtained by vaporizing a liquid raw material, which is a raw material for the thin film, and a carrier gas to the film forming container and adsorbing the raw material gas to the substrate;
A reaction gas supply unit that supplies a reaction gas that reacts with a component of the source gas adsorbed on the substrate to form the atomic layer to the film formation container;
With
The source gas supply unit
A raw material tank for storing the liquid raw material and generating the raw material gas by vaporizing the liquid raw material inside;
A carrier gas supply unit that mixes the source gas and the carrier gas in the source tank by supplying a carrier gas to the source tank;
A storage tank for supplying the mixed gas to the film formation container after storing the mixed gas of the source gas and the carrier gas at a pressure lower than that of the raw material tank and higher than that of the film formation container;
Is provided.

  It is preferable that the amount of the source gas stored in the storage tank is equal to or more than an amount necessary for forming one atomic layer on the substrate.

A first valve that opens and closes a pipe connecting the raw material tank and the storage tank;
A second valve for opening and closing a pipe connecting the storage tank and the film formation container;
A control unit for controlling the first valve and the second opening and closing;
The control unit opens the second valve simultaneously with closing the first valve when supplying the source gas to the film forming container, or after closing the first valve,
It is preferable to open the first valve simultaneously with closing the second valve when the supply of the source gas to the film forming container is stopped or after closing the second valve.

A second aspect of the present invention is an atomic layer deposition method for forming a thin film comprising an atomic layer on a substrate,
The raw material gas and the carrier gas are mixed in the raw material tank by supplying the carrier gas to the raw material tank in which the liquid raw material that is the raw material of the thin film is stored and the raw material gas vaporized from the liquid raw material is generated. Step to
Storing a mixed gas of the source gas and the carrier gas in a storage tank;
While the supply of the mixed gas to the storage tank is stopped, the mixed gas is supplied from the storage tank to the film formation container, and the source gas is adsorbed on the substrate disposed in the film formation container. Steps,
Supplying a reaction gas that reacts with a component of a source gas adsorbed on the substrate and forms the atomic layer to the film formation container after stopping the supply of the mixed gas to the film formation container;
It is characterized by repeating.

  According to the atomic layer deposition apparatus of the present invention, a sufficient amount of source gas is obtained by storing a mixed gas obtained by mixing a source gas in which a liquid source is vaporized and a carrier gas in a storage tank and then supplying the mixture to a film formation container. Can be supplied. In addition, the flow rate of the mixed gas can be sufficiently increased, and by reliably purging the source gas, it is possible to prevent abnormal film thickness and generation of particles. Therefore, a thin film having a uniform film thickness and good film quality can be formed on the substrate.

It is the schematic which shows an example of the atomic layer deposition apparatus of embodiment. It is the schematic which shows an example of the source gas supply part of an atomic layer deposition apparatus. It is a flowchart which shows an example of the atomic layer deposition method of embodiment. It is a figure which shows the process in which a thin film is formed on a board | substrate.

<Embodiment>
(Configuration of atomic layer deposition system)
First, the configuration of the atomic layer deposition apparatus of this embodiment will be described with reference to FIG. FIG. 1 is a schematic configuration diagram showing an example of an atomic layer deposition apparatus 10 of the present embodiment. The atomic layer deposition apparatus 10 of this embodiment supplies a source gas and a reactive gas alternately, and forms a thin film on the substrate S in units of atomic layers. At that time, plasma can be generated to increase the reaction activity. In the present embodiment, parallel plate electrodes are used for generating plasma, but the present invention is not limited to this method. In particular, in this embodiment, a thin film is formed using a raw material that is liquid at normal temperature and normal pressure.
The atomic layer deposition apparatus 10 according to the present embodiment includes a film formation container 20, an exhaust unit 40, a high frequency power supply 50, a control unit 52, a source gas supply unit 70, a reaction gas supply unit 80, and a purge gas supply unit 90. And comprising.

The film forming container 20 includes a vacuum chamber 30 and an injector 60.
First, the vacuum chamber 30 will be described. The vacuum chamber 30 includes a support portion 32, an upper electrode 36, and a lower electrode 38. A lower electrode 38 is provided on the upper surface of the support portion 32. Here, the lower electrode 38 is grounded. The substrate S is supported by lift pins 44 that penetrate the support portion 32 from below the vacuum chamber 30. The lift pins 44 can be moved up and down by a lift mechanism 46, and the lift mechanism 44 moves the lift pins 44 downward while the lift pins 44 support the substrate S, whereby the substrate S is placed on the lower electrode 38. Placed.
In addition, a heater 34 is provided inside the support portion 32, and the temperature of the substrate S can be adjusted by the heater 34. For example, in the case of plasma ALD, the substrate S is heated to 50 to 200 ° C.

The upper electrode 36 is provided above the substrate S and is connected to the high frequency power supply 50. When the high frequency power supply 50 supplies a high frequency current having a predetermined frequency, plasma is generated between the upper electrode 36 and the lower electrode 38.
The high frequency power supply 50 is connected to the control unit 52. The timing at which the high frequency power supply 50 supplies the high frequency current to the upper electrode 36 is controlled by the control unit 52.

A film thickness measuring device 56 and a film quality measuring device 57 are connected to the control unit 52.
The film thickness measuring device 56 measures the thickness of the thin film formed on the substrate S and inputs measurement information to the control unit 52. The film thickness can be measured at four points on the outer peripheral portion of the substrate and one point on the central portion by, for example, reflectance spectroscopy (light interference method).
The film quality measuring device 57 measures the film quality of the thin film formed on the substrate S and inputs measurement information to the control unit 52. The film quality is measured by, for example, measuring the refractive index of the thin film at four points on the outer peripheral portion of the substrate and one point on the central portion. For example, a high refractive index can be evaluated as a dense thin film.
In the present embodiment, the film thickness measuring device 56 is provided outside the vacuum chamber 30, and after the film formation, the thickness of the thin film on the substrate S taken out from the vacuum chamber 30 is measured. Further, the film thickness measuring device 56 may be provided inside the vacuum chamber 30 and the thickness of the thin film formed on the substrate S in the vacuum chamber 30 may be measured.
The control unit 52 generates a control signal and supplies the control signal to the source gas valve 78, the reaction gas valve 84, the exhaust valve 54, and the purge gas valve 94.

  Next, the injector 60 will be described. The injector 60 supplies the source gas and the reaction gas into the vacuum chamber 30. The injector 60 is formed with a raw material gas supply port 62 that is elongated in the horizontal direction (perpendicular to the plane of FIG. 1), a reaction gas supply port 64 that is elongated in the horizontal direction, and a purge gas supply port 66 that is elongated in the horizontal direction. ing. The source gas supplied from the source gas supply unit 70 is supplied into the film forming container 20 through the source gas supply port 62. Further, the reaction gas supplied from the reaction gas supply unit 80 is supplied into the film forming container 20 through the reaction gas supply port 64. Further, the reaction gas supplied from the purge gas supply unit 90 is supplied into the film forming container 20 through the purge gas supply port 66.

The exhaust unit 40 exhausts the source gas, the reaction gas, and the purge gas supplied into the film forming container 20 (vacuum chamber 30) through the exhaust pipe. The exhaust unit 40 is, for example, a dry pump.
The exhaust pipe 42 is connected to an exhaust port provided in the vacuum chamber 30. The exhaust pipe 42 is provided with an exhaust valve 54. The degree of opening and closing of the exhaust valve 54 and the timing of opening and closing are controlled by the control unit 52. The exhaust valve 54 is opened at a predetermined opening according to the control signal of the control unit 52, whereby the gas in the vacuum chamber 30 is exhausted by the exhaust unit 40 through the exhaust pipe 42.
When the exhaust unit 40 exhausts the inside of the vacuum chamber 30, the degree of vacuum in the vacuum chamber 30 is maintained at about 10 Pa to 100 Pa even when the source gas, the reaction gas, and the purge gas are supplied into the vacuum chamber 30.

Next, the source gas supply unit 70 will be described. FIG. 2 is a schematic configuration diagram illustrating an example of the source gas supply unit 70. The source gas supply unit 70 includes a liquid source storage unit 71, a storage tank 72, a carrier gas supply unit 73, a first valve V1, and a second valve V2.
The liquid source storage unit 71 stores a liquid source used for forming a thin film. The liquid raw material stored in the liquid raw material storage unit 72 is, for example, TMA (trimethylaluminum), TDMAS (trisdimethylaminosilane), TEMAZ (tetrakisethylmethylamino-zirconium), or TEMAH (tetrakisethylmethylamino-hafnium). The carrier gas is supplied from the carrier gas supply unit 73 to the liquid source storage unit 71, and the source gas in which the liquid source is vaporized and the carrier gas are mixed. The liquid raw material storage unit 71 is provided with a pressure gauge P1 for measuring the internal pressure.

  The storage tank 72 is connected to the liquid raw material storage unit 71 through a pipe provided with the first valve V1, and is connected to the injector 60 through a pipe provided with the second valve V2. When the first valve V1 is opened, the storage tank 72 is supplied with a mixed gas of the source gas mixed in the liquid source storage unit 71 and the carrier gas. When the second valve V2 is open, the mixed gas in the storage tank 72 is supplied to the injector 60. The storage tank 72 is provided with a pressure gauge P2 that measures the internal pressure. Supply of the mixed gas from the storage tank 72 to the injector 60 is performed by a pressure difference between the pressure in the storage tank 72 and the pressure in the film formation container 20. The pressure in the storage tank 72 decreases to the pressure of the film forming container 20 at the minimum while the second valve V2 is opened. A single supply amount of the mixed gas from the storage tank 72 to the injector 60 is determined by the pressure difference in the storage tank 72 before and after opening the second valve V2. The mixed gas for one supply amount includes a source gas in an amount more than that required for forming one atomic layer on the substrate.

The carrier gas supply unit 73 includes a carrier gas storage unit 74, a decompressor (regulator) 75, valves V3 and V4, and a pressure gauge P3.
Carrier gas is stored in the carrier gas storage unit 74. The carrier gas is an inert gas such as N ₂ gas or a rare gas (eg, Ar).
The carrier gas storage unit 74 is connected to the liquid source storage unit 71 by piping. In this pipe, a decompressor 75, a valve V3, a pressure gauge P3, and a valve V4 are provided in this order from the carrier gas storage unit 74 side.
The decompressor 75 decompresses the carrier gas in the carrier gas storage unit 74 to a predetermined pressure (for example, 0.1 to 0.5 MPa) and supplies it to the valve V3 side.
In addition, the purge gas mentioned later may be used as carrier gas, and the purge gas storage part 92 mentioned later may be used as the carrier gas storage part 74. FIG.

The pressure gauge P3 is used to measure the pressure of the carrier gas in the pipe between the valve V3 and the valve V4.
The valves V3 and V4 are used to supply a predetermined amount of carrier gas to the liquid source storage unit 71 as follows.
First, the valve V3 is opened with the valve V4 closed.
(1) When the pressure gauge P3 pressure of the carrier gas in the pipe between the valves V3 and the valve V4 is detected that reaches a predetermined pressure V _a, closing the valve V3, open the valve V4. Then, the pressure in the liquid material reservoir 71 is lower than V _a, the carrier gas in the pipe between the valves V3 and the valve V4 is supplied to the liquid material reservoir 71 side.
(2) When the pressure gauge P3 detects that the pressure of the carrier gas in the pipe between the valve V3 and the valve V4 has dropped to a predetermined pressure V _b (V _a > V _b ), the valve V4 is closed and the valve V3 open.
By repeating the procedures (1) and (2) above, the carrier gas is supplied to the liquid raw material storage unit 71 minutely, and the inside of the liquid raw material storage unit 71 is brought to a desired pressure (for example, 0.1 MPa). it can.

  Each first valve V 1, second valve V 2, valves V 3, V 4 and pressure gauges P 1, P 2, P 3 of the source gas supply unit 70 are connected to the control unit 52. The control unit 52 controls the supply amount and supply timing of the source gas by controlling the first valve V1, the second valve V2, the valves V3, and V4.

Here, a method of supplying the mixed gas of the source gas and the carrier gas from the source gas supply unit 70 to the injector 60 will be described.
(3) First, the first valve V <b> 1 is opened with the second valve V <b> 2 and the valve V <b> 4 closed, and the mixed gas is supplied from the liquid source storage unit 71 into the storage tank 72.
(4) Next, when it is detected that the pressure in the storage tank 72 has increased to a predetermined pressure (for example, 0.01 MPa), the first valve V1 is closed.
(5) Next, the second valve V <b> 2 is opened at a predetermined timing, and the mixed gas is supplied to the injector 60.
(6) Thereafter, the second valve V2 is closed at a predetermined timing, and the supply of the mixed gas to the injector 60 is stopped.
(7) Moreover, the inside of the liquid raw material storage part 71 is raised to a desired pressure by repeating the procedures of (1) and (2).
By repeating the above procedure, the mixed gas of the source gas and the carrier gas is supplied from the source gas supply unit 70 to the injector 60.

Next, the reactive gas supply unit 80 will be described. The reactive gas supply unit 80 includes a reactive gas storage unit 82 and a reactive gas valve 84.
The reactive gas storage unit 82 stores a reactive gas used for forming a thin film. The reaction gas stored in the reaction gas storage unit 82 is, for example, O ₂ gas or N ₂ gas.
The reactive gas valve 84 is connected to the control unit 52. The opening degree of the reaction gas valve 84 is controlled by the control unit 52. The reaction gas valve 84 is opened while the supply of the source gas into the film formation container 20 is stopped, and the reaction gas is supplied into the film formation container 20.

Next, the purge gas supply unit 90 will be described. The purge gas supply unit 90 includes a purge gas storage unit 92 and a purge gas valve 94.
The purge gas storage unit 92 stores a purge gas such as Ar gas. The purge gas valve 94 is connected to the control unit 52. The opening degree of the purge gas valve 94 is controlled by the control unit 52.
N ₂ gas may be used as the purge gas. When N ₂ gas is used as the reaction gas, the reaction gas may be used instead of the purge gas, and the reaction gas supply unit 80 may be used instead of the purge gas supply unit 90.
The above is the schematic configuration of the atomic layer deposition apparatus 10 of the present embodiment.

(Atomic layer deposition method)
Next, an atomic layer deposition method using the atomic layer deposition apparatus 10 of the present embodiment will be described with reference to FIGS. FIG. 3 is a flowchart showing an example of the atomic layer deposition method of the present embodiment. 4A to 4D are diagrams showing a process of forming a thin film on the substrate S.

First, the source gas supply unit 70 supplies the source gas into the film forming container 20 as a mixed gas with the carrier gas (step S101). The control unit 52 sends a control signal for opening the second valve V <b> 2, and the mixed gas 110 of the source gas and the carrier gas is supplied from the storage tank 72 to the inside of the film forming container 20.
As shown in FIG. 4A, in step S101, the mixed gas 110 is supplied to the inside of the film forming container 20, the source gas in the mixed gas 110 is adsorbed on the substrate S, and the adsorption layer 102 is formed. It is formed.

Next, the purge gas supply unit 90 supplies the purge gas into the film forming container 20 (step S102). The control unit 52 sends a control signal for opening the purge gas valve 94, and supplies the purge gas 112 from the purge gas storage unit 92 into the film forming container 20. For example, the purge gas valve 94 is opened for 0.1 second, and the purge gas 112 is supplied into the film forming container 20. Further, the exhaust unit 40 exhausts the mixed gas 110 and the purge gas 112 inside the film forming container 20. The exhaust unit 40 exhausts the mixed gas 110 and the purge gas 112 inside the film forming container 20 for 2 seconds, for example. At this time, the opening degree of the exhaust valve 54 is adjusted so that the flow rate of the mixed gas 110 is uniform in the entire region of the substrate S, and the exhaust unit 40 exhausts the gas inside the film forming container 20.
As shown in FIG. 4B, the purge gas 112 is supplied into the film forming container 20 in step S <b> 102, and the source gas not adsorbed on the substrate S in the mixed gas 110 is removed from the film forming container 20. Purged. The purge gas 112 may be supplied simultaneously when the mixed gas 110 is supplied.

Next, the reactive gas supply unit 80 supplies the reactive gas into the film forming container 20 (step S103). The reaction gas valve 84 is opened at the timing controlled by the control unit 52, and the reaction gas 114 is supplied from the reaction gas supply port 64 into the film formation container 20. The reactive gas supply unit 80 supplies the reactive gas 114 into the film forming container 20 for 1 second, for example. At this time, the opening degree of the exhaust valve 54 is adjusted so that the flow rate of the reaction gas 114 is uniform in the entire region of the substrate S, and the exhaust unit 40 exhausts the gas inside the film formation container 20.
As shown in FIG. 4C, the reaction gas 114 is supplied into the film forming container 20 in step S103.

  Further, the high frequency power supply 50 supplies a high frequency current having a predetermined frequency to the upper electrode 36 to generate plasma between the upper electrode 36 and the lower electrode 38 (step S104). The high frequency power supply 50 generates the plasma of the reaction gas 114 for 0.2 seconds, for example. When the high frequency power supply 50 generates plasma of the reaction gas 114, the reaction gas 114 reacts with the adsorption layer 102, and the thin film layer 104 is formed.

Note that the timing at which the high-frequency power supply 50 generates the plasma of the reaction gas 114 may be the same as the timing at which the reaction gas supply unit 80 supplies the reaction gas 114 into the film forming container 20.
Further, when the reaction gas 114 reacts with the adsorption layer 102 without generating plasma, step S104 can be omitted. In this case, the heater 34 heats the substrate S to 200 to 400 ° C. (thermal ALD) so that the reaction gas 114 sufficiently reacts with the adsorption layer 102.

Next, the purge gas supply unit 90 supplies the purge gas 112 into the film forming container 20 (step S105). The purge gas supply unit 90 supplies the purge gas 112 into the film forming container 20 for 0.1 seconds, for example. The exhaust unit 40 exhausts the reaction gas 114 and the purge gas 112 inside the film formation container 20. At this time, the opening degree of the exhaust valve 54 is adjusted so that the flow rate of the reaction gas 114 is uniform in the entire region of the substrate S, and the exhaust unit 40 exhausts the gas inside the film formation container 20.
As shown in FIG. 4D, the purge gas 112 is supplied into the film forming container 20 and the reaction gas 114 is purged from the film forming container 20 in step S105.

The thin film layer 104 for one atomic layer is formed on the substrate S by the steps S101 to S105 described above. Thereafter, the thin film layer 104 having a desired film thickness can be formed by repeating steps S101 to S105.
Note that each time steps S101 to S105 are repeated a predetermined number of times, the film thickness may be measured by the film thickness measuring device 56 to adjust the supply amount of the mixed gas.

In step S101, since the source gas is supplied into the film forming container 20 as a mixed gas with the carrier gas, the supply amount thereof is the total pressure of the mixed gas obtained by combining the vapor pressure of the source gas and the partial pressure of the carrier gas. It becomes the corresponding speed. Compared with the case where the source gas is supplied into the film forming container 20 only by the vapor pressure of the source gas, a sufficient amount of the source gas can be supplied.
Further, since the flow rate of the mixed gas is larger than the flow rate of only the source gas, the residence time of the source gas in the film forming container 20 is reduced. For this reason, the source gas can be reliably purged, and abnormal film thickness and generation of particles can be prevented.

  Further, instead of directly supplying the raw material gas to the film forming container 20, the gas mixture is supplied from the liquid raw material storage unit 71 to the film forming container 20 via the storage tank 72, thereby adiabatic expansion of the mixed gas. Since it is possible to alleviate the temperature drop and increase the raw material gas flow rate, it is possible to reduce the amount of raw material gas liquefaction and to solve the shortage of raw material purge. For this reason, it becomes possible to prevent the liquid material droplets from adhering to the inner wall of the film formation container 20 and to suppress excessive reaction with the reaction gas, and to prevent the generation of powder serving as a particle source.

<Example>
An AlON thin film was formed on a 370 mm × 470 mm G2 glass substrate using the same film forming apparatus as shown in FIG. TMA (trimethylaluminum) was used as the liquid source (Al source), and oxygen and nitrogen were used as the reaction gas.
The same cycle as shown in FIG. 3 was repeated 600 times to form an AlON thin film. At this time, an excessive amount of raw material gas (3.4 mg / cycle) was used to promote abnormal film thickness and generation of particles. The amount of carrier gas supplied was 1 L / cycle.

After film formation, the film thickness was measured at four points on the outer peripheral portion of the substrate and one point on the central portion by reflectance spectroscopy, and the average film thickness was 100 nm. No particles were observed in the formed thin film.
After the film formation, when the thickness of the thin film formed on the inner wall of the injector 60 and the inner wall of the exhaust port 42a was measured, the film thickness was 90 nm.

<Comparative example>
An AlON thin film was formed on a 370 mm × 470 mm G2 glass substrate using the same film forming apparatus as shown in FIG. TMA (trimethylaluminum) was used as the liquid source (Al source), and oxygen and nitrogen were used as the reaction gas.
The same cycle as shown in FIG. 3 was repeated 600 times to form an AlON thin film. At this time, an excessive amount of raw material gas (3.4 mg / cycle) was used to promote abnormal film thickness and generation of particles. Note that the carrier gas was not supplied, but only the above-mentioned source gas was supplied.

After film formation, the film thickness was measured at four points on the outer peripheral portion of the substrate and one point on the central portion by reflectance spectroscopy, and the average film thickness was 100 nm. Particles were observed in the formed thin film.
After the film formation, when the thickness of the thin film formed on the inner wall of the injector 60 and the inner wall of the exhaust port 42a was measured, the film thickness was 125 nm.

  Although the atomic layer deposition apparatus and the atomic layer deposition method of the present invention have been described in detail above, the present invention is not limited to the above embodiment. It goes without saying that various improvements and modifications may be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10 Atomic layer deposition apparatus 20 Film-forming container 30 Vacuum chamber 32 Support part 34 Heater 36 Upper electrode 38 Lower electrode 40 Exhaust part 42 Exhaust pipe 44 Lift pin 46 Lifting mechanism 50 High frequency power supply 52 Control part 54 Exhaust valve 56 Film thickness measuring apparatus Reference Signs List 60 injector 62 source gas supply port 64 reaction gas supply port 66 purge gas supply port 70 source gas supply unit 71 liquid source storage unit 72 storage tank 73 carrier gas supply unit 74 carrier gas storage unit 75 decompressor 80 reaction gas supply unit 82 reaction gas Storage unit 84 Reaction gas valve 90 Purge gas supply unit 92 Purge gas storage unit 94 Purge gas valve 102 Adsorption layer 104 Thin film layer 110 Gas mixture 112 Purge gas 114 Reaction gas P1, P2, P3 Pressure gauge S Substrate V1 First valve V2 Second valve V3 V4 valve

Claims (4)

An atomic layer deposition apparatus for forming a thin film comprising an atomic layer on a substrate,
A film forming container having a substrate disposed therein;
A raw material gas supply unit for supplying a mixed gas obtained by mixing a raw material gas obtained by vaporizing a liquid raw material, which is a raw material for the thin film, and a carrier gas to the film forming container and adsorbing the raw material gas to the substrate;
A reaction gas supply unit that supplies a reaction gas that reacts with a component of the source gas adsorbed on the substrate to form the atomic layer to the film formation container;
With
The source gas supply unit
A raw material tank for storing the liquid raw material and generating the raw material gas by vaporizing the liquid raw material inside;
A carrier gas supply unit that mixes the source gas and the carrier gas in the source tank by supplying a carrier gas to the source tank;
A storage tank for supplying the mixed gas to the film formation container after storing the mixed gas of the source gas and the carrier gas at a pressure lower than that of the raw material tank and higher than that of the film formation container;
An atomic layer deposition apparatus comprising:   2. The atomic layer deposition apparatus according to claim 1, wherein an amount of the source gas stored in the storage tank is equal to or more than an amount necessary to form one atomic layer on the substrate. A first valve that opens and closes a pipe connecting the raw material tank and the storage tank;
A second valve for opening and closing a pipe connecting the storage tank and the film formation container;
A control unit for controlling the first valve and the second opening and closing;
The control unit opens the second valve simultaneously with closing the first valve when supplying the source gas to the film forming container, or after closing the first valve,
3. The atom according to claim 1, wherein the first valve is opened simultaneously with closing the second valve when the supply of the source gas to the film formation container is stopped or after the second valve is closed. Layer deposition equipment. An atomic layer deposition method for forming a thin film comprising an atomic layer on a substrate,
A liquid raw material that is a thin film raw material is stored, and a carrier gas is supplied to a raw material tank in which a raw material gas vaporized from the liquid raw material is generated, whereby the raw material gas and the carrier gas are contained in the raw material tank. Mixing, and
Storing a mixed gas of the source gas and the carrier gas in a storage tank;
While the supply of the mixed gas to the storage tank is stopped, the mixed gas is supplied from the storage tank to the film formation container, and the source gas is adsorbed on the substrate disposed in the film formation container. Steps,
Supplying a reaction gas that reacts with a component of a source gas adsorbed on the substrate and forms the atomic layer to the film formation container after stopping the supply of the mixed gas to the film formation container;
The atomic layer deposition method characterized by repeating.

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