JPH0719755B2 - Thin film forming method by plasma CVD - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is plasma CVD (Chemical Vapor Deposition).
The present invention relates to a thin film forming method by plasma CVD for forming a thin film on a substrate by a method.

[Prior Art] As shown in FIG. 4, a conventional method for forming a thin film by plasma CVD is that a substrate 3 to be processed is laid down on a substrate heater 2 in a vacuum reactor 1 and placed above the substrate 3. Is provided with an electrode 4 facing the substrate heater 2, a high frequency power is applied from a high frequency power source 5 between the electrode 4 and the substrate heater 2, and a raw material gas supply means consisting of a pipe is provided in the vacuum reaction container 1. In step 6, the source gas was supplied and a thin film was formed on the surface of the substrate 4 by the plasma CVD method.

[Problems to be Solved by the Invention] However, in such a conventional thin film forming method by plasma CVD, since a thin film can be formed only on one surface (upper surface) of the substrate 3, the other surface is also formed. Since the work of forming a thin film has to be performed again, there is a problem of inefficiency.

An object of the present invention is to provide a thin film forming method by plasma CVD capable of simultaneously forming thin films on both surfaces of a substrate.

[Means for Solving Problems] The structure of the present invention for achieving the above object will be described. In the method for forming a thin film by plasma CVD of the present invention, a pair of raw materials are provided in a common reaction chamber of a vacuum reaction container. The gas outflow electrodes are opposed to each other and are arranged so as to move back and forth so as to be able to approach and separate from each other, a processing substrate is placed in the center between the two source gas outflow electrodes, and the source gas outflow electrodes are grounded, High-frequency power is applied to the substrate while causing the source gas to flow toward both sides of the substrate to generate plasma between the substrate and the source gas outflow electrodes, and both sides of the substrate in the plasma are generated. It is characterized by forming a thin film.

[Operation] With this configuration, plasma can be generated on both sides of the substrate by the substrate and each source gas outflow electrode on both sides thereof, and the source gas from each source gas outflow electrode can be supplied to both sides of the substrate. A thin film can be simultaneously formed on both sides of the substrate.

In particular, since both sides of the substrate are placed in a common reaction chamber, reaction conditions (pressure, temperature, electric field, etc.) are made equal, and plasma is uniformly generated, so that thin films of the same type are formed on both sides of the substrate. It can be formed with the same thickness.

Furthermore, the plasma generated on both sides of the substrate is affected by the applied high-frequency power, the outer shape and mounting state of the substrate / electrode, the shape of the vacuum reaction container, etc., and becomes non-uniform and is formed on both sides of the substrate. Although the film quality of the thin film becomes unstable and the uniformity becomes poor, the distance between the substrate and the source gas outflow electrode can be adjusted by arranging the pair of source gas outflow electrodes so that they can move back and forth and move toward and away from each other. By doing so, the plasma on both sides of the substrate becomes uniform, the film quality of the thin film becomes stable, and the uniformity can be improved.

In addition, since both source gas outflow electrodes are grounded and high frequency power is applied to the substrate to generate plasma between them and both source gas outflow electrodes, plasma concentrates on the substrate and ions are efficiently generated in this. It collides well and a hard and dense thin film can be formed on both sides of the substrate.

[Embodiment] Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3. As shown, the plasma CVD of this embodiment
In the apparatus, 1 in the common reaction chamber of the vacuum reaction vessel 1
The pair of source gas outflow electrodes 7 are arranged vertically and face each other and parallel to each other. Each source gas outflow electrode 7 is made of metal and has a large number of gas outflow holes 8 dispersed therein. On the back surface of each raw material gas outflow electrode 7, a raw material gas consisting of a funnel-shaped distribution chamber forming body 9A made of metal, a metal pipe 9B for supplying the raw material gas to this, and a joint 9C connecting the two. A supply means 9 is provided. The joint 9C is airtightly connected and fixed to the pipe 9B, and the distribution chamber forming body 9A is attached to the joint 9C so as to move back and forth by screwing so that the two source gas outflow electrodes 7 can approach and separate from each other. The pipe 9B is led out to the outside of the vacuum reaction container 1 in an airtight manner. The source gas outflow electrode 7 is grounded via the source gas supply means 9.
At the center between the two source gas outflow electrodes 7, a processing substrate 3 is placed supported by a metal substrate holder 10. The substrate holder 10 is detachably fitted and supported on the upper end of the current-carrying support 11. High frequency power is applied to the substrate 3 from the external high frequency power source 5 through the matching box 12, the power supply cord 13, the energization support 11, and the substrate holder 10. An exhaust pipe 14 for evacuating with a vacuum pump (not shown) is provided below the vacuum reaction container 1.

Next, a thin film forming method of this embodiment performed using such a plasma CVD apparatus will be described.

The common reaction chamber of the vacuum reaction vessel 1 is evacuated to 0.1 Tor.
Keep in r position. The raw material gas supplied together with the carrier gas from the raw material gas supply means 9 on both sides is supplied to both raw material gas outflow electrodes 7.
From the gas outflow holes 8 to the both sides of the substrate 3. When high-frequency power is applied to the substrate 3, plasma is generated between the substrate 3 and the source gas outflow electrodes 7 on both sides of the substrate 3, and the source gas flowing out from each source gas outflow electrode 7 is activated in the plasma. A thin film is simultaneously formed on both surfaces of No. 3. In this case, the high frequency applied to the substrate 3 is 13.56 MHz. The high frequency power is electrically matched by the matching box 12 and applied to the substrate 3. Both source gas outflow electrodes 7 are symmetrical with respect to the substrate 3, and the flow rate of the source gas is the same, but the distance from the substrate 3 is moved back and forth so that the plasma on both sides of the substrate is uniform if necessary. And move them toward or away from each other to adjust. Evacuation is performed from the lower center so that there is no uneven influence in the plasma.

The film formation is ended by turning off the high frequency power supply 5 after stopping the supply of the raw material gas. The film formation is started by applying a high frequency to the substrate 3 and then increasing the raw material gas. The substrate 3 is held in the same place during film formation. It is preferable that the substrate holder 10 be made as thin as possible so that the flow of the raw material gas in a vacuum is not disturbed.

Example The substrate 3 was an aluminum disk of 8.89 cm (3.5 ″), and the substrate holder 10 was made of stainless steel. The thickness of the substrate 3 was 2 to 3 mm.
The distance between and was adjusted in the range of 20 to 50 mm on each side. Each raw material gas outflow electrode 7 was made of stainless steel and had an outer diameter larger than the outer diameter of the substrate by 20% or more. Piping
A heater was wound around the outer circumference of 9B, and the outer circumference was surrounded by an insulator such as tetrafluoroethylene, and the temperature of the pipe 9 was adjusted so as to be constant.

Deposition time: 30 seconds High frequency power: 150W, 13.56MHz Pipe temperature: 100 ° C Carrier gas: Ar, 40cc / min Raw material gas: Monomer that becomes gas phase at high temperature Deposition film thickness: 300Å Film thickness distribution: 300Å ± 5% [Effect of the invention] As described above, in the thin film forming method by plasma CVD according to the present invention, a pair of source gas outflow electrodes are arranged facing each other in a common reaction chamber of a vacuum reactor. A substrate is placed between a pair of source gas outflow electrodes, and high-frequency power is applied between the substrate and both source gas outflow electrodes to generate plasma on both sides of the substrate. Since the raw material gas is supplied from the outflow electrode to activate it, so that the film is formed on the substrate,
Film formation can be performed on both surfaces of the substrate at the same time. Therefore, according to the present invention, film formation by the plasma CVD method can be performed efficiently. In particular, in the present invention, since both sides of the substrate are placed in a common reaction chamber, the reaction conditions (pressure, temperature, electric field, etc.) are made equal and plasma is uniformly generated, so that both sides of the substrate are of the same kind. The thin film can be easily formed with the same quality and the same thickness.

Furthermore, by arranging a pair of source gas outflow electrodes so as to face each other and moving back and forth so as to be able to approach and separate from each other, and by making it possible to adjust the distance between the two source gas outflow electrodes on the substrate, The plasma on both sides of the substrate becomes uniform, the film quality of the thin film becomes stable, and the uniformity can be improved.

In addition, since both source gas outflow electrodes are grounded and high frequency power is applied to the substrate to generate plasma between them and both source gas outflow electrodes, plasma concentrates on the substrate and ions are efficiently generated in this. It collides well and a hard and dense thin film can be formed on both sides of the substrate.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of an apparatus for carrying out a thin film forming method by plasma CVD according to the present invention, FIG. 2 is a front view of a source gas outflow electrode used in FIG. 1, and FIG. Is an electrical system diagram of the apparatus shown in FIG. 1, and FIG. 4 is a longitudinal sectional view of a conventional plasma CVD apparatus. 1 ... Vacuum reactor, 3 ... Substrate, 5 ... High frequency power supply,
7 ... Raw material gas outflow electrode, 8 ... Raw material gas outflow hole, 9 ...
... Source gas supply means.

Claims (1)

[Claims] 1. A pair of raw material gas outflow electrodes are arranged to face each other in a common reaction chamber of a vacuum reaction vessel so that they can be moved back and forth to approach and separate from each other, and a processing substrate is provided for the both raw material gases. Placed in the center between the outflow electrodes, the both source gas outflow electrodes are grounded, and high-frequency power is applied to the substrate while flowing out the source gas toward both sides of the substrate to cause outflow of the substrate and both source gas. Plasma is generated between the electrodes,
A method for forming a thin film by plasma CVD, comprising forming a thin film on both surfaces of the substrate in the plasma.