JP2000273638A - Chemical vapor deposition device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chemical vapor deposition device provided with a clean ing means capable of importantly removing reaction products deposited on a gas dispersion board and capable of reducing the frequency of wet cleaning for the gas dispersion board executed per film formation of the prescribed number and remarkably improving the working ratio of the device. SOLUTION: In a chemical vapor deposition device in which a gas dispersion board 2 uniformly feeding a gaseous starting material and the substrate to be film-formed are oppositely arranged on the inside of an airtight reaction chamber 1, a cleaning means of removing reaction products deposited on the face opposite to the substrate to be film-formed in the gas dispersion board 2 by high frequency sputtering is provided, and the gas dispersion board 2 is subjected to cleaning by the cleaning means, by which the frequency of wet cleaning is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical vapor deposition apparatus having a structure in which a gas dispersion plate for uniformly supplying a source gas on a surface of a substrate on which a film is to be formed is disposed in a reaction chamber, and more particularly, to a chemical vapor deposition apparatus for depositing the gas on the gas dispersion plate. The present invention relates to a chemical vapor deposition apparatus provided with a cleaning means for removing a reaction product.

[0002]

2. Description of the Related Art In this type of chemical vapor deposition apparatus, there is a problem that particles formed by decomposition of a reaction gas in a gas phase adhere to a substrate on which a film is to be formed, thereby deteriorating the film quality. For this reason, in this type of chemical vapor deposition apparatus, cleaning such as (a) plasma cleaning and (b) gas cleaning is performed after a predetermined number of film formation substrates have been formed.

[0003]

SUMMARY OF THE INVENTION The conventional (a)
In plasma cleaning, many thin films are made of halogen compounds.
Chemical with halogen plasma utilizing high vapor pressure
This is a method for removing deposits in a vapor phase growth apparatus. others
Deposits with high vapor pressure of halogen compounds (SiO _Two, P
poly-Si, α-Si, W)
Recently, as a dielectric film for highly integrated memory and non-volatile memory
Ferroelectrics (BST, SBT) that have been studied
Cleaning effect due to low vapor pressure of halogen compounds
Stainless steel, which is the main constituent material of the reaction chamber
Ferroelectric material that is susceptible to corrosion and oxidation reaction of steel
Organometallic raw material for chemical vapor deposition equipment reaches deposition substrate
Before being decomposed by the reaction with halogen remaining on the inner wall.
The problem is that the film cannot be transported and cannot be deposited.
Could not be applied.

On the other hand, the conventional gas cleaning of the above (b) is a method of performing cleaning by exhausting a reaction product generated by chemically reacting a deposit inside a reaction chamber with a cleaning gas. It is an effective method if a compound having a high vapor pressure can be produced by the chemical reaction described above. As the cleaning gas, (b-1) ClF3, (b-
2) HFAC (1,1,1,5,5,5-hexafloro-2,4-pentanedio
ne).

[0005] Of the above cleaning gases, ClF3 is B
When ST is cleaned, Ti can be cleaned because the vapor pressure is high, but Ba and Sr can be cleaned only when heated to near 800 ° C., so that the vapor pressure of the halogen compound cannot be increased. Therefore, a so-called cold wall ferroelectric CVD apparatus is used. Not applicable to

On the other hand, there is a report that HFAC can clean heavy metals such as Cu and Fe even at a relatively low temperature of about 200 ° C., but practical cleaning of rare earth elements such as Ba and Sr which is the object of the present invention. There was a drawback that speed could not be realized.
In addition, HFAC also adheres to the management of the transport route to the substrate on which a film is to be formed, and remains due to Ba, Sr,
There is also a concern that the decomposition reaction of the organometallic raw material of Ti may occur to make normal film formation impossible.

On the other hand, according to the results of an independent investigation by the inventors of the present invention, a vertical single-wafer type chemical vapor deposition system in which a film-forming substrate is opposed to a gas dispersion plate disposed in a reaction chamber. In the phase film forming apparatus, it was found that most of the particles adhering to the film formation substrate were formed by peeling off deposits on the gas dispersion plate facing the film formation substrate. This is considered to be due to the fact that the gas dispersion plate was heated by the heating by the radiant heat from the deposition target substrate, which was at the highest temperature, and was deposited by the decomposition reaction of the source gas. It is considered that the number of particles falling on the deposition target substrate can be significantly reduced by cleaning the gas dispersion plate intensively based on the results of the investigation.

[0008]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above points, and has a cleaning means capable of mainly removing deposits deposited on a gas distribution plate,
By removing the reaction products deposited on the gas dispersion plate and performing cleaning, the number of times of wet cleaning of the gas dispersion plate performed for each predetermined number of films is reduced,
It is an object of the present invention to provide a chemical vapor deposition apparatus capable of greatly improving the operation rate of the apparatus.

[0009]

According to a first aspect of the present invention, a gas dispersion plate for uniformly supplying a source gas into an airtight reaction chamber is opposed to a film-forming substrate. In the chemical vapor deposition apparatus arranged, cleaning means is provided for removing a reaction product deposited on a surface of the gas dispersion plate facing the film formation substrate by high-frequency sputtering.

[0010] The invention described in claim 2 is the same as the claim 1.
In the chemical vapor deposition apparatus according to the above, the attaching member is disposed at a position facing the gas dispersion plate, and a collecting means for attaching and collecting the reaction product removed by the cleaning means to the attaching member is provided. Features.

The invention described in claim 3 is the same as the claim 2
In the chemical vapor deposition apparatus described in the above, the recovery means is provided with a transport means for moving the adhesion member in and out of the reaction chamber.

According to a fourth aspect of the present invention, in the chemical vapor deposition apparatus according to the second or third aspect, the attachment member has a flat central portion and a cylindrical outer peripheral portion. And

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration example of a chemical vapor deposition apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes a reaction chamber (film formation chamber), in which a gas dispersion plate 2 having a large number of holes is disposed, and a substrate on which a film is to be formed is provided below the gas dispersion plate 2. (Not shown) substrate mounting table 1 for mounting
The substrate mounting table 10 has a built-in substrate heater (not shown) for heating the substrate on which a film is to be formed.

A vaporizer 8 for generating a raw material gas is disposed above the reaction chamber 1. The reaction chamber 1 is electrically divided vertically above and below the gas dispersion plate 2 via an insulating joint 7-1, and furthermore, the reaction chamber 1 and the vaporizer 8 are electrically divided via an insulating joint 7-2. I have. The substrate mounting table 10 has a plate-shaped attachment member 3
Is placed. Reference numeral 14 denotes an adhesion member storage chamber provided outside the reaction chamber 1, and the adhesion member storage chamber 14 is connected to the reaction chamber 1 via the adhesion member carry-in / out port 11 and the valve 12. Further, the attachment member storage chamber 14 is provided with an attachment member transport unit 13 for transporting the attachment member 3 such as a robot arm.

A vacuum pump 6 is connected to the reaction chamber 1 so that the degree of vacuum in the reaction chamber 1 can be detected by a vacuum gauge 9. A high frequency power supply (RF power supply) 4 is connected via a matching circuit 5 to an upper part of the reaction chamber 1 which is electrically divided into upper and lower parts by the insulating joint 7-1.

In the chemical vapor deposition apparatus having the above structure,
When cleaning is performed by removing the reaction products deposited on the gas dispersion plate 2, the valve 12 is opened and the adhesion member 3 stored in the adhesion member storage chamber 14 by the adhesion member transporting means 13.
Is carried into the reaction chamber 1 and placed on the substrate mounting table 10.
In this state, while the valve 12 is closed and the reaction chamber 1 is evacuated by the vacuum pump 6, argon (Ar) gas is introduced through the vaporizer 8. By applying a high-frequency voltage from a high-frequency power supply 4 through a matching circuit 5 to the gas dispersion plate 2 electrically insulated from the reaction chamber 1 and the vaporizer 8 by the insulating joints 7-1 and 7-2, An argon plasma is generated.

In the argon plasma, argon ions are accelerated by an ion sheath formed on the front surface (lower surface) of the gas dispersion plate 2, and the reaction products deposited on the gas dispersion plate 2 by the sputtering action of the argon ions are removed. . The removed reaction product is attached to the attachment member 3 facing the gas dispersion plate 2.
Adheres to This argon gas discharge treatment is performed for a certain period of time.
And the supply of argon gas is stopped. Thereafter, the valve 12 is opened, the adhering member conveying means 13 is operated to transfer the adhering member 3 to the adhering member storage chamber 14, and the valve 12 is closed to complete the cleaning.

The attachment member 3 is made of SiC, Al
Although it is preferable to use a dedicated jig represented by N, a dummy wafer can be used instead.

In the above-structured chemical vapor deposition apparatus,
Cleaning was performed under the following conditions each time 100 BST films were formed on an 8-inch silicon wafer under the conditions of forming a 500-nm thick BST film.

(Cleaning conditions) Discharge gas Argon (Ar) gas Discharge pressure 0.1 Torr Distance between gas dispersion plate 2 and attachment member 3 30 mm RF frequency 13.56 MHz RF power 1 kW Discharge time 5 minutes

The cleaning was carried out under the above conditions, and the number of particles attached to the gas dispersion plate 2 was counted by counting the number of particles that fell off the reaction product attached to the gas dispersion plate 2 and fell on the silicon wafer as the substrate on which the film was formed. As a result, it was found that when the cleaning according to the present invention was performed, the amount of adhered particles could be suppressed to a level two orders of magnitude lower than when the cleaning according to the present invention was not performed.

In the example shown in FIG. 1, the attachment member 3 is a flat plate-like member. Therefore, all of the deposits sputtered from the gas dispersion plate 2 do not adhere to the depositing member 3 and those that have scattered in the outer peripheral direction are not collected, which may become a particle source. Therefore, as shown in FIG. 2, by providing the projection 3 a in a tubular shape on the outer periphery of the attachment member 3, it is possible to collect even those sputtered in the outer peripheral direction of the gas dispersion plate 2.

1 and 2, the adhesion member 3 is supplied from the adhesion member storage chamber 14 to the reaction chamber 1 by the adhesion member transport means 13, and at the time of recovery from the reaction chamber 1 to the adhesion member storage chamber 14, The substrate mounting table 10 is lowered by the substrate mounting table elevating mechanism 15 as shown by the solid line, and during the cleaning according to the present invention, the substrate mounting table 10 is attached so that the removed reaction product can easily adhere to the attaching member 3. 10 rises as shown by the dashed line.

FIG. 3 is a view for explaining a case of forming a high dielectric or ferroelectric thin film of, for example, barium titanate / strontium by the chemical vapor deposition apparatus having the above-mentioned structure. A film formation substrate of a silicon wafer is mounted on the substrate mounting table 10, and the inside of the reaction chamber 1 is evacuated by the vacuum pump 6. The vaporizer 8 includes a liquid raw material G1 and a carrier gas G2.
Is supplied to the source gas vaporized by the vaporizer 8. The raw material gas is supplied to a reaction gas supply unit 16 above the gas dispersion plate 2 together with oxygen gas (O ₂ ).

In FIG. 3, the attaching member carrying means 13 carries the wafer W, and stores the wafer W in the attaching member storage chamber 14. When the wafer W is transferred between the reaction chamber 1 and the adhesion member storage chamber 14 (supply and collection of the wafer W to the reaction chamber 1) by the adhesion member conveying means 13, the substrate mounting table elevating mechanism 1
5, the substrate mounting table 10 is lowered as shown by a solid line,
At the time of film formation, the substrate mounting table 10 is moved up and down as shown by a dashed line.

The film formation substrate is heated by a heater built in the substrate mounting table 10 and is maintained at a predetermined temperature.
A high-dielectric or ferroelectric film is formed on the film-forming substrate by uniformly injecting a mixed gas (reactive gas) of a source gas and an oxygen gas from the gas dispersion plate 2 toward the film-forming substrate.

In the chemical vapor deposition apparatus having the above structure, the reaction gas supply section 16 is formed above the gas dispersion plate 2 disposed above the reaction chamber 1. The configuration of the shower head is not limited to this. The shower head is provided with a gas dispersion plate capable of uniformly injecting the reaction gas relative to the substrate on which the film is to be formed. The specific configuration is not particularly limited as long as it is configured to apply a high-frequency voltage from a high-frequency power supply to the plate.

[0028]

As described above, according to the present invention, the cleaning means for removing the reaction products deposited on the surface of the gas dispersion plate facing the substrate on which the film is to be formed by high frequency sputtering is provided. Therefore, the reaction products deposited on the gas dispersion plate can be easily removed. Therefore, the wet cleaning, which has been performed every time a film is formed on, for example, 100 substrates, can be performed every 1000 films, and the operation rate of the chemical vapor deposition apparatus is greatly improved. Can be done.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration example of a chemical vapor deposition apparatus according to the present invention.

FIG. 2 is a diagram showing a configuration example of a chemical vapor deposition apparatus according to the present invention.

FIG. 3 is a diagram showing a configuration example of a chemical vapor deposition apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reaction chamber 2 Gas dispersion plate 3 Attachment member 4 High frequency power supply (RF power supply) 5 Matching circuit 6 Vacuum pump 7-1 Insulation joint 7-2 Insulation joint 8 Vaporizer 9 Vacuum gauge 10 Substrate mounting table 11 Adhesion member carrying-in / out port 12 Valve 13 Adhering Member Conveying Means 14 Adhering Member Storage Room 15 Substrate Placement Table Elevating Mechanism 16 Reaction Gas Supply Unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4G077 TG02 TH13 4K030 AA14 BA42 CA04 DA06 EA01 EA05 EA06 FA03 GA02 GA12 KA12 KA17 KA45 5F045 AF19 BB08 BB10 BB14 EB02 EB05 EB08 EH05 EN08

Claims (4)

[Claims] 1. A chemical vapor deposition apparatus in which a gas dispersion plate for uniformly supplying a source gas into an airtight reaction chamber and a substrate on which a film is to be formed are arranged opposite to each other. A chemical vapor deposition apparatus comprising cleaning means for removing a reaction product deposited on a surface facing a substrate by high-frequency sputtering. 2. The chemical vapor deposition apparatus according to claim 1, wherein an attachment member is disposed at a position facing the gas dispersion plate, and the reaction product removed by the cleaning means is attached to the attachment member. A chemical vapor deposition apparatus characterized by comprising a recovery means for recovering by vapor deposition. 3. The chemical vapor deposition apparatus according to claim 2, wherein the recovery unit includes a transport unit that moves the attachment member in and out of the reaction chamber. . 4. The chemical vapor deposition apparatus according to claim 2, wherein the attachment member has a flat plate at the center and a tubular shape at the outer periphery. apparatus.