JP4617142B2 - Thin film manufacturing method - Google Patents

Description

  The present invention relates to a thin film manufacturing method for forming a carbon-containing solid film thinly and uniformly on the surface of a substrate or the like.

Conventionally, what uses a plasma CVD apparatus is known as what forms a carbon content solid film on the surface of a substrate etc. (Patent Document 1)
Japanese Patent Publication No. 6-60404

  However, when forming a thin film on the surface of a substrate or the like using a plasma CVD apparatus, the inside of the chamber has to be depressurized, so that the size of the substrate is restricted and it is difficult to make the plasma act uniformly. . In addition, there is a problem that the concentration of active species and the concentration of raw materials generated are low, and the growth rate of the thin film is slow when grown from the gas phase.

  The present invention has been made paying attention to such a point, and an object thereof is to provide a manufacturing method capable of forming a thin film uniformly and at high speed over a wide area.

In order to achieve the above-mentioned object, the present invention sprays a raw material fluid composed of carbon dioxide and a hydrocarbon derivative in a supercritical state onto a catalyst body accommodated in a chamber, and performs a raw material reaction by a catalytic reaction between the catalyst body and the raw material fluid. It is characterized in that at least a part of the fluid is decomposed and the substrate is exposed to an atmosphere of active species generated by the decomposition to form a carbon- containing solid film on the substrate.

  In the present invention, at least a part of the raw material fluid is decomposed by contact between the raw material fluid and the catalyst body to form carbon radicals, and a carbon-containing solid film is formed on the surface of the substrate placed in the atmosphere of the carbon radicals. To form. In addition, the hydrogen generated by the decomposition quickly enters the supercritical fluid of carbon dioxide and does not remain in the film. For this reason, the whole chamber becomes a uniform atmosphere, and the carbon-containing solid film can be uniformly formed on the entire substrate.

  In the present invention, carbon dioxide and the raw material fluid are both introduced into the chamber in a supercritical state and brought into contact with the active species generator in the chamber to form free carbon, which is thin on the substrate surface at a low temperature. A dense carbon-containing solid film can be formed. Therefore, it has been possible to obtain a diamond-like carbon film having a good quality even on a glass or plastic substrate, which has been difficult to produce in the past and has a low glass transition temperature.

  Moreover, in this case, since the concentration of the raw material fluid is much higher than that of a commonly used CVD apparatus, a pinhole-free and entirely uniform thin film can be formed to increase the frequency of nucleation. it can. In addition, since the atmosphere in the chamber does not need to be evacuated, the workability is excellent.

  The figure shows an example of an apparatus for carrying out the present invention. The active species generator (2) is arranged in the chamber (1), and the chamber (1) is partitioned by the active species generator. The raw material fluid blow-in port (4) is positioned in one space (3) partitioned by the active species generation layer, and the gas discharge port (6) is positioned in the other space (5). 5) The substrate (7) is located inside.

As the active species generating means (2), a resistance heating element such as platinum, tungsten, cobalt, nickel, iron, or an alloy thereof is used, and the reaction conditions are adjusted by heating to a temperature of 2000 ° C. or less. It is designed to be used. The catalyst may be heated by laser heating or electromagnetic wave heating. In this case, 2000 ° C. is a temperature at which carbon dioxide causes a plasma phenomenon, and is heated to a temperature range that does not cause a plasma phenomenon at a temperature equal to or higher than the critical temperature (31 ° C.) of carbon dioxide.
Moreover, it is also possible to use a platinum wire or an iron wire as the active species generator (2).

To the case of forming a carbon-containing solid film and, as the carrier fluid as carbon dioxide (8) and the raw material fluid introduced from the carrier gas inlet (41) as a mixture of hydrocarbon derivative (9) using The fluid is brought into contact with the active species generator (2) in a supercritical state.

  As the substrate (7), a glass substrate, an aluminum substrate, a silicon substrate, or a synthetic resin substrate is used.

  In the solid film manufacturing method configured as described above, carbon dioxide (8) and a hydrocarbon derivative (9) as a carbon source are supplied into the chamber (1) in a supercritical state. When carbon dioxide and a hydrocarbon derivative are introduced in a supercritical state, both fluids are uniformly mixed and contacted with the active species generator (2), the hydrocarbon derivative is decomposed into carbon and hydrogen, and this free carbon is converted into a substrate. Reaching the surface of (7), a thin, dense and hard polycrystalline diamond-like carbon film is formed. At this time, carbon dioxide acts as a carrier gas and is not a raw material for free carbon.

  The hydrogen gas decomposed from the raw material fluid by contact with the active species generator (2) is immediately dissolved in the supercritical carbon dioxide and discharged from the gas outlet (6) together with the introduced carbon dioxide. Is done.

  In the above embodiment, carbon dioxide and a hydrocarbon derivative are individually introduced into the chamber (1) in a supercritical state. However, the carbon dioxide and the hydrocarbon derivative are mixed in a supercritical state, and the mixed fluid May be introduced into the chamber (1).

[Example 1]
First, a previously cleaned glass substrate (7) is set in the chamber (1). Next, the turbo molecular pump (55) and the rotary pump (56) are operated to depressurize the chamber (1) to about 1 to 2 × 10 ⁻⁶ Pa, and this state is maintained for about 5 minutes. Exhaust moisture and oxygen brought inside. Further, the temperature of the substrate (7) is kept at 200 ° C. by heating.

  Next, the active species generator (platinum catalyst) (2) is energized and its temperature is raised to about 1600-1800 ° C. In this example, it is set to 1800 ° C. And hold | maintain for 10 minutes in this state.

Next, methane (CH ₄ ) is also introduced into the chamber (1) from the reaction gas control system. That is, in this example, supercritical carbon dioxide flow rate and 90 sccm / min, supplying the raw material gas by making the CH ₄ flow rate 9 sccm / min (100% methane) into the chamber (1). The pressure in the chamber is maintained at 5 MPa and 50 ° C. Film formation is performed at a film formation rate of 80 nm / min for 1 minute to form a diamond-like carbon film having a thickness of about 40 nm.

When the raw material gas is supplied into the chamber (1) in this way, the active species generator (2) supplies energy for chemically reacting these to the raw material gas, whereby CH ₄ is decomposed and C is generated. As described above, carbon is deposited on the surface of the glass substrate (7), and the diamond-like carbon film (10) is formed at a high speed. Since the obtained diamond-like carbon film (10) is formed by this apparatus, the crystal grain size is controlled to a desired grain size of 100 nm or less (for example, a fine grain size of about 1 to 2 nm) according to the deposition conditions. Further, the hydrogen content is also suppressed to an atomic ratio of about 0.1 to 2.0 at%.

When the diamond-like carbon film (10) is formed in this way, the flow rate of CH ₄ gas is made zero by the reaction gas control system, and only carbon dioxide is allowed to flow. If this state continues for 5 minutes, the power supply to the active species generator (2) is stopped and the temperature is lowered. Next, the flow rate of carbon dioxide is also reduced to zero, and the pressure in the reaction chamber (51) is reduced to about 1 to 2 × 10 ⁻⁶ Pa, and this state is maintained for about 5 minutes, and in particular CH ₄ introduced into the chamber Exhaust. Thereafter, the inside of the chamber is returned to atmospheric pressure, and the glass substrate (7) is taken out.

[Example 2]
First, a previously cleaned glass substrate (7) is set in the chamber (1). Next, the turbo molecular pump (55) and the rotary pump (56) are operated to depressurize the reaction chamber (51) to about 1-2 × 10 ⁻⁶ Pa, and this state is maintained for about 5 minutes. Exhaust moisture and oxygen brought into the chamber. Further, the temperature of the substrate (7) is kept at 200 ° C. by heating.

  Next, the active species generator (platinum diameter catalyst) (2) is energized and its temperature is raised to about 1600-1800 ° C. In this example, it is set to 1800 ° C. And it hold | maintains for 10 minutes in this state.

Next, methanol is also introduced into the chamber (1) from the reaction gas control system. That is, in this example, the source gas is supplied into the chamber (1) by setting the supercritical carbon dioxide flow rate to 90 sccm / min and the methanol flow rate to 9 sccm / min (100% methanol). The pressure in the chamber is maintained at 5 MPa and 50 ° C. Film formation is performed at a film formation rate of 80 nm / min for 1 minute to form a diamond-like carbon film having a thickness of about 40 nm.

  When the source gas is supplied into the chamber (1) in this way, the active species generator (2) decomposes the source gas, whereby carbon radicals are first generated and hydrogen is desorbed. Then, these react and carbon is deposited on the surface of the glass substrate (7) as described above, and a diamond-like carbon film is formed at a high speed. The obtained diamond-like carbon film is formed by this apparatus, so that the crystal grain size is controlled to a desired grain size of 100 nm or less (for example, a fine grain size of about 1 to 2 nm) according to the deposition conditions. Further, the hydrogen content is also suppressed to an atomic ratio of about 0.1 to 2.0 at%.

When the diamond-like carbon film (10) is formed in this way, the flow rate of methanol gas is reduced to zero by the reaction gas control system, and only carbon dioxide is allowed to flow. If this state continues for 5 minutes, the power supply to the active species generator (2) is stopped and the temperature is lowered. Next, the flow rate of carbon dioxide is also reduced to zero, and the pressure in the chamber (1) is reduced to about 1 to 2 × 10 ⁻⁶ Pa. This state is maintained for about 5 minutes, and CH ₄ introduced into the chamber is exhausted. To do. Thereafter, the inside of the chamber is returned to atmospheric pressure, and the glass substrate (7) is taken out.

  In the present invention, since a thin and dense carbon-containing solid film (DLC) can be formed on the substrate surface, various tools, jigs, friction-resistant materials, speaker diaphragms, fusion furnace wall materials, semiconductor elements, etc. It can be applied to the manufacturing field.

It is a schematic block diagram of the apparatus which implements the method of this invention.

  DESCRIPTION OF SYMBOLS 1 ... Chamber, 2 ... Active species generator, 3 ... Space, 4 ... Raw material gas inlet, 5 ... Space, 6 ... Gas exhaust port, 7 ... Substrate, 8 ... Carrier fluid, 9 ... Raw material fluid, 10 ... Diamond like Carbon, 41 ... carrier gas inlet, 55 ... turbo molecular pump, 56 ... rotary pump.

Claims (5)

In the chamber, a hydrocarbon derivative as a raw material fluid and carbon dioxide as a carrier fluid are mixed to form a supercritical state, and a catalytic reaction generates active species in the raw material fluid in the supercritical fluid, and the fluid is used as a substrate. A thin film manufacturing method comprising forming a carbon-containing solid film on a substrate by spraying. The thin film manufacturing method according to claim 1, wherein at least one metal selected from platinum, tungsten, cobalt, nickel, iron or an alloy thereof is used as the catalyst body. The thin film manufacturing method according to claim 1, wherein carbon dioxide as a carrier fluid and a hydrocarbon derivative as a raw material fluid are mixed in advance and then introduced into a chamber to form a carbon-containing solid film. The thin film manufacturing method according to claim 1, wherein carbon dioxide as a carrier fluid and a hydrocarbon derivative as a raw material fluid are individually introduced into a chamber to form a carbon-containing solid film. The thin film manufacturing method according to any one of claims 1 to 4, wherein a diamond-like carbon solid film is formed using methane or methanol as the hydrocarbon derivative.

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