JP2002115060A - Thermal cvd system for depositing graphite nanofiber thin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal CVD system by which a graphite nanofiber thin film having a uniform film thickness distribution can be deposited on the large and rectangular substrate. SOLUTION: This system is provided with a vacuum chamber 12, and an infrared ray lamp 17 is arranged oppositely to the substrate S to be treated. The gaseous mixture of a carbon-containing gas and gaseous hydrogen required for depositing a graphite nanofiber thin film is introduced through a gas jetting nozzle means 19 provided below the height position of the substrate S to be attached to a substrate holder 16 so as to surround the substrate S in the vicinity of its outer circumference. The nozzle means connected to a gas source at the outside of the chamber has a gas flow passage 191 at its inside, and plural gas injectors 192 communicating to the gas flow passage are provided in a row on its upper face.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a thermal CVD apparatus for forming a graphite nanofiber thin film on a substrate.

[0002]

2. Description of the Related Art A graphite nanofiber thin film is formed on a component requiring an electroluminescent element as a substitute for a flat panel display (field emission display) or an electron tube of a CRT, for example. To form a graphite nanofiber thin film, for example, thermal CVD (Chemical vapor d)
An eposition apparatus is used, and such a thermal CVD apparatus is known from Japanese Patent Application No. 2000-89468.

[0003] The thermal CVD apparatus has a vacuum chamber capable of forming a vacuum atmosphere. Inside the vacuum chamber, a substrate made of glass, Si, or the like containing Fe or Co
A substrate holder on which the substrate having the pattern is formed is provided. An infrared transmission window made of heat-resistant glass such as quartz glass is provided on the upper wall surface of the vacuum chamber so as to face the substrate to be processed. An infrared lamp, which is a heating means, is provided outside the transmission window. Then, while heating the substrate to be processed by the infrared lamp,
For example, a mixed gas of hydrogen gas and carbon monoxide is introduced into the vacuum chamber from one gas inlet provided on the side wall of the vacuum chamber to grow a graphite nanofiber thin film on the substrate.

[0004]

The mixed gas introduced into the vacuum chamber needs to reach the substrate without being heated to a predetermined temperature or higher. For this reason, in the above-mentioned apparatus, the position of the gas introduction port which can be provided in the vacuum chamber side wall is appropriately designed, but it is difficult to control the film thickness distribution of the graphite nanofiber thin film by introducing the gas from one place. . In this case, it is conceivable to provide a plurality of gas inlets on the side wall of the film formation chamber and to introduce a mixed gas into the vacuum chamber from these gas inlets. However, in this case, aside from a substantially square substrate having a size of about 200 mm × 200 mm and a circular substrate having a diameter of about 200 mm, for example, a graphite nanometer is used for a large substrate having a size of 1 m × 1 m or a rectangular substrate having a size of A4. It is difficult to appropriately design the position of the gas inlet so that the film thickness distribution of the fiber thin film becomes uniform.

It is an object of the present invention to provide a thermal CVD apparatus capable of forming a graphite nanofiber thin film having a uniform film thickness distribution irrespective of the size and outer shape of a substrate to be processed.

[0006]

In order to solve this problem, in a CVD apparatus according to the present invention, a heating means is provided above a vacuum chamber so as to face a substrate to be processed. Thermal CVD for forming a graphite nanofiber thin film on a substrate by introducing a mixed gas of carbon-containing gas and hydrogen gas into a vacuum chamber while heating
In the apparatus, the introduction of the mixed gas is performed through gas injection nozzle means provided below the height position of the substrate to be processed and surrounding the substrate to be processed in the vicinity of the outer periphery thereof, and The gas ejection nozzle means connected to a gas source outside the chamber has a gas flow path therein, and a plurality of gas injection ports communicating with the gas flow path are arranged on the upper surface thereof. .

According to the present invention, the mixing once jetted upward from a plurality of gas jets arranged in the upper surface of the gas jet nozzle means provided so as to surround the substrate to be processed in the vicinity of the outer periphery thereof. The gas is diffused uniformly over the entire upper surface of the substrate to be processed, and then descends uniformly downward.
Since the processing reaches the entire processing target substrate uniformly, even if the processing target substrate has a relatively large dimension or a rectangular external shape, the processing target substrate does not matter regardless of the size or the external shape of the processing target substrate. A graphite nanofiber thin film having a uniform thickness distribution can be formed on a processing substrate.

Here, when the gas injection nozzle means is provided in the vacuum chamber, the gas injection nozzle means can be heated together with the substrate to be processed by a heating device provided above the vacuum chamber so as to face the substrate to be processed. . Then, when the surface temperature of the gas injection nozzle means is equal to or higher than a predetermined temperature, a graphite nanofiber thin film can grow on the surface. Since the growth of the graphite nanofiber thin film causes contamination, it is necessary to frequently clean or replace the gas injection nozzle means. In this case, if the gas injection nozzle means is formed of a metal having a high thermal conductivity and is arranged in surface contact with the side wall and / or bottom wall of the vacuum chamber capable of cooling the outer wall surface, the graphite nanofiber thin film is formed. Below the temperature at which it can grow,
The surface temperature of the gas injection nozzle means can be maintained, and the frequency of cleaning and replacement can be reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, for example, a thermal CVD apparatus 1 for forming a graphite nanofiber thin film on an A4-size rectangular substrate to be processed S includes a load lock chamber 11 and a film forming chamber 12. The load lock chamber 11 and the film formation chamber 12 are connected via a gate valve 13.
The load lock chamber 11 is a substrate S to be processed such as glass or Si, on which a metal thin film such as Fe or Co is formed on a film-forming surface, is exposed to a vacuum atmosphere once, so that the moisture on the surface of the substrate to be processed is reduced. Plays a role in removing the like. For this purpose, a vacuum pump 111 is connected to the load lock chamber 11 and a vacuum gauge 112 for monitoring the degree of vacuum is provided. The load lock chamber 11 is provided with a transfer arm 15 for transferring a substrate holder 16 on which the substrate S to be processed is mounted. The transfer arm 15 is
A first arm 152 fixed to an upper end of a rotary shaft 151 having a servomotor (not shown);
Arm 153 pivotally supported by the other end of the second arm 153, and a fork-shaped support pivotally supported by the other end of the second arm 153 and supporting the substrate holder 16 on which the substrate S to be processed is mounted from below. And a third arm 154 having a portion. By rotating the second and third arms 153 and 154, the transfer arm 15 can expand and contract. In addition, the rotary shaft 151 can be moved up and down with a short stroke for delivery of the substrate holder 16 on which the substrate S to be processed is mounted. The substrate S to be processed mounted on the substrate holder 16 is housed in the load lock chamber 11 from the outside by the transfer arm 15,
After evacuating to a predetermined degree of vacuum (for example, about 0.01 Torr), the gate valve 13 is opened, and the substrate S to be processed is placed in the film forming chamber 12 evacuated to a predetermined degree of vacuum (for example, about 0.01 Torr). Is transported together with the substrate holder 16. Then, the transfer arm 15 is moved to the load lock chamber 1 again.
When returning to 1, the gate valve 13 is closed.

The transfer arm 1 is provided on the bottom wall of the film forming chamber 12.
The three columns 121 on which the substrate holder 16 on which the substrate S to be processed carried by the substrate 5 is mounted are placed so as to form a substantially triangular shape corresponding to the area of the substrate holder 16. . The column 121 located on the load lock chamber 11 side is located in the gap between the fork-shaped support portions of the third arm 154 and the transfer arm 1
5 serves as a guide. In this embodiment, the substrate holder 16 on which the substrate to be processed S is mounted is transported. However, the substrate holder 16 is fixed on the support 121 in the film forming chamber 12 and the substrate to be processed S Can be transported.

An infrared transmitting window 122 made of heat-resistant glass such as quartz glass is provided on the upper wall surface of the film forming chamber 12 so as to face the substrate S to be processed. This transmission window 1
A plurality of infrared lamps 17, which are heating means having a predetermined arrangement, are provided outside the substrate 22.
Is heated evenly over its entire surface. Similarly to the load lock chamber 11, the film formation chamber 12 is provided with a vacuum pump 123 so that a vacuum atmosphere can be formed, and a vacuum gauge 12 for monitoring the degree of vacuum.
4 are provided. Further, a pipe bypassing the vacuum pump 123 is provided with the valve 123c interposed.

Further, the mixed gas supply system 1 is
8 are connected. The mixed gas supply system 18 includes a valve 181a, a gas flow controller 181b, a pressure controller 18
1c and a carbon-containing gas supply system 181 connected in series with a carbon-containing gas cylinder 181e such as carbon monoxide via a valve via a valve 181d, a valve 182a to a gas flow regulator 182b, a pressure regulator 182c, and a valve 182d. And a hydrogen gas supply system 182 connected in series to the hydrogen gas cylinder 182e via a gas pipe. Further, the carbon-containing gas supply system 181 and the hydrogen gas supply system 182 are connected to the valves 181a and 182a and the film forming chamber 12
And a mixed gas of a carbon-containing gas and a hydrogen gas is introduced into the film forming chamber 12. Here, the reason why the hydrogen gas is used in addition to the carbon-containing gas to form the graphite nanofiber thin film is because of dilution and catalytic action in the gas phase reaction.

When the mixed gas is introduced into the film forming chamber 12 through the mixed gas supply system 18, the film forming chamber 1 is located above the substrate S to be processed as in a conventional thermal CVD apparatus.
It is difficult to make the thickness distribution of the graphite nanofiber thin film uniform for a relatively large substrate or a rectangular substrate by introducing the mixed gas from one gas inlet provided on the side wall of the second. Therefore, in the present embodiment, the introduction of the mixed gas is performed below the height position of the substrate S to be processed, and the gas injection nozzle means 19 provided so as to surround the substrate S near the outer periphery thereof. It was decided to do it through.

Referring to FIGS. 2 and 3, the annular gas injection nozzle means 19 has a mixed gas flow path 191 therein, and a plurality of gas injection paths communicating with the gas flow path 191 on its upper surface. The mouths 192 are arranged. On the upper surface of the gas injection nozzle means 19, a mixed gas supply unit 193 having a joint communicating with the gas flow path 191 is opened, and one end of a gas pipe of the mixed gas supply system 18 is connected to the joint. . Here, when the gas injection nozzle means 19 is formed as described above, the gas injection nozzle means 19 itself can be heated together with the substrate S to be processed by the infrared lamp 17. Then, when the surface temperature of the gas injection nozzle means 19 becomes higher than a predetermined temperature, a graphite nanofiber thin film can grow thereon. Since the growth of the graphite nanofiber film causes contamination, it is necessary to frequently clean or replace the gas injection nozzle means 19. For this reason, in the present embodiment, the gas injection nozzle means 19 is formed from copper, which is a metal material having high thermal conductivity, and is disposed in surface contact with the bottom wall surface of the film forming chamber 12.
Then, a cooling water line 20 is meanderingly provided around the outer wall of the film forming chamber 12, and the cooling water flows through the cooling water line 20 during the execution of the graphite nanofiber thin film forming process. The outer wall of can be cooled. Thereby, the gas injection nozzle means 19 is maintained at a temperature lower than the temperature at which the graphite nanofiber film grows. In the present embodiment, the gas injection nozzle means 19 is annular, but the outer shape is not limited as long as the gas mixture can be uniformly injected into the film forming chamber 12. The height of the column 121 on which the substrate holder 16 is placed corresponding to the disposition position of the gas injection nozzle means 19 is determined by the height of the mixing jet injected upward from the gas injection port 192 of the gas injection nozzle means 19. The size is set so that the gas reaches the target substrate S without being heated to a predetermined temperature or more by the infrared lamp 17. A cooling water line 2 is provided around the outer wall of the film forming chamber 12.
Although 0 is arranged in a meandering manner, a water-cooled jacket covering the outer wall of the film forming chamber 12 may be used.

Next, a process for forming a graphite nanofiber thin film using the above apparatus will be described.

As the substrate S to be processed, a substrate obtained by vapor-depositing Fe to a thickness of 100 nm on a glass substrate by an EB vapor deposition method is used. The substrate S on which the substrate to be processed S on which Fe is deposited is mounted on the substrate holder 16 from the outside of the load lock chamber 11 and temporarily stored in the load lock chamber 11 by the transfer arm 15, and the vacuum pump 111 is started. The vacuum evacuation is performed to about 0.01 Torr while measuring with the vacuum gauge 112. At the same time, the film forming chamber is also equipped with a vacuum pump 12
3 and start measurement with the vacuum gauge 124
Evacuation is performed until the pressure becomes about rr. After the load lock chamber 11 and the film forming chamber 12 reach a predetermined degree of vacuum,
After a predetermined time has elapsed, the gate valve 13 is opened, and the substrate holder 16 on which the substrate S to be processed is mounted is placed on the substrate holder support 121 in the film forming chamber 12. In this state,
Carbon monoxide gas cylinder 181e and hydrogen gas cylinder 182
e, the main valve is opened, the pressure is adjusted to about 1 atm (absolute pressure) by pressure regulators 181c and 182c, and the valve 181 is opened.
a, 182a are opened and the gas flow controllers 181b, 182 are opened.
b, a mixed gas of carbon monoxide gas and hydrogen gas (C
O: H ₂ = 30: 70 gas ratio) to about 1000 sccm
The gas was introduced into the film forming chamber 12 from below the substrate holder 16 to be processed through the gas injection nozzle means 19 to perform gas replacement. At this time, the vacuum pump 123 is stopped, and valves 123 provided before and after the vacuum pump 123 are provided.
a, 123b in the closed state and the valve 12 of the bypass pipe
3c is kept in an open state, and the film forming chamber 12 is almost at atmospheric pressure (7.
60 Torr). In this case, the mixed gas was introduced while the substrate S to be processed was heated to 500 ° C. by energizing the infrared lamp 17.

After the pressure in the film forming chamber 12 became atmospheric pressure, a growth reaction of graphite nanofibers was performed on the substrate at 500 ° C. for 10 minutes by a thermal CVD method. When the carbon monoxide gas reaches the substrate to be processed S, the carbon monoxide is dissociated, and the F deposited on the substrate to be processed is removed.
A graphite nanofiber thin film was formed only on the e thin film.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a configuration of a CVD apparatus of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a partial perspective view of the gas injection nozzle means.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Thermal CVD apparatus 12 Film-forming chamber 16 Substrate holder 17 Infrared lamp 19 Gas injection nozzle means 191 Gas flow path 192 Gas injection port S Substrate to be processed

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Harukuni Furuse 2500 Hagizono, Chigasaki-shi, Kanagawa Japan Vacuum Engineering Co., Ltd. F-term (reference) 4G046 CA01 CA02 CB03 CB08 CC06 CC09 4K030 AA14 AA17 BA27 BB12 BB14 CA06 CA17 EA05 EA06 FA10 HA04 4L037 CS04 FA03 FA20 PA03 PA06 PA17 PA28 UA02

Claims (2)

[Claims] A heating means is provided at an upper portion of a vacuum chamber so as to face a substrate to be processed, and a mixed gas of a carbon-containing gas and a hydrogen gas is supplied into the vacuum chamber while heating the substrate to be processed by the heating means. In the thermal CVD apparatus for forming a graphite nanofiber thin film on the substrate by introducing the mixed gas, the introduction of the mixed gas is performed below the height position of the substrate to be processed and the substrate to be processed is positioned near the outer periphery thereof. This is performed through gas injection nozzle means provided so as to surround the gas injection nozzle means connected to a gas source outside the vacuum chamber. A thermal CVD apparatus, wherein a plurality of communicating gas injection ports are arranged in a row. 2. The gas injection nozzle means is formed of a metal having a high thermal conductivity, and is disposed in surface contact with a side wall and / or a bottom wall of a vacuum chamber capable of cooling an outer wall surface. The thermal CVD apparatus according to claim 1.