JPS63169386A - Formation of thin film - Google Patents

Abstract

PURPOSE:To form a uniform thin film on the surfaces of various parts by arranging a cylindrical column housing a body to be coated in a hybrid resonance space wherein the electric field strength of a microwave is maximized and having the interaction of an electric field and a magnetic field. CONSTITUTION:The cylindrical column 10' housing the bodies 10 to be coated with a thin film is arranged in a plasma producing space 1, and the column 10' is rotated and provided with microvibration. The space 1 is then evacuated to <=about 1X10<-6>Torr, Ar, etc., are then introduced into the space 1 to increase the pressure to about 1X10<-4>Torr, a microwave is impressed from a microwave oscillator 4, and magnetic fields are impressed by magnets 5 and 5' to produce high-density plasma in the space 1. The surface of the body 10 in the column 10' is cleaned in this way. C2H2, etc., are further introduced while introducing Ar, the pressure in the space 1 is increased to about 0.1X10<-1>-3X10<2>Torr, and the concn. of the productive gas is increased while keeping the produced plasma state. By this method, the carbon atom excited by high energy is formed, carbon is deposited on many bodies 10 in the column 10', and a diamond film is formed.

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention applies a microwave electric field and an external magnetic field, uses their interaction, and generates a reactive gas in a space where the electric field is greatest or in the vicinity thereof. A coating forming means is provided in a cylindrical column configured to allow transmission through the cylinder, and this column is rotated or slightly vibrated to form a coating on the entire surface of the object for forming a thin film, and also to form a coating well even in the recesses of the object. The present invention relates to a thin film forming method for forming a film using hybrid resonance.

[Conventional technology]

Conventionally, as a means for forming thin films, ECR (electron cyclotron!!: S) conditions, i.e., I Xl0-3 to I Xl0-
Under the condition of 5 torr, active species are created at a pressure low enough for at least one electron to make one round, and by utilizing the divergent magnetic field, a substrate is placed at a position "away" from this resonant space, where the coating, especially A method using electron cyclotron resonance (also referred to as ECR) to form a film having an amorphous structure is known.

In this ECRCVD method, active species are pinch-jigged using a magnetic field to increase their energy, thereby increasing the electron energy and increasing efficiency. Film formation or anisotropic etching was performed by delivering a reactive gas (with gas flow in only one direction).

[Conventional problems]

However, in this method of forming a film using showered reactive gas, it is completely impossible to form a film on the side surfaces of recesses or projections having uneven surfaces. Furthermore, it has been completely impossible to form a coating on the shadow areas of many parts, such as gears, jigs, and other coating objects made of plastic, metal, or ceramics.

In addition, even if we try to form a film at a high pressure of 0, 1 to 300 torr, especially 3 torr or more, which is not the area where such ECR exists, plasma is not generated and it is impossible to use high-density plasma. It was said that It was previously considered impossible to form a crystalline film under such high pressure. However, the inventor of the present invention
It is possible to create high-density plasma even at high pressures of torr, and such plasma is not ECR but "hybrid resonance".
We discovered that this is a new mode. We have also discovered that in such a hybrid resonance region, it is possible to form a film on the side surface of the uneven portion of the film-forming object.

[Means to solve the problem]

The present invention uses 0.1 to 300 torr, preferably 3 to 3 torr.
The coating is formed using high-density plasma using "hybrid resonance" at a high pressure of 0 torr.

Furthermore, the entire surface of the coating-forming parts, such as plastic, ceramic, or metal parts (gears, screws, decorative jigs, or abrasive particles), is to be coated.

These film-forming objects are held in a cylindrical column, and plasma-formed gas is passed through the column to coat the surfaces of the objects with the reaction products.

For this purpose, an object having a surface to be formed is disposed in or near a region where the electric field strength of microwave power is maximum. Furthermore, in order to uniformly coat the entire surface of the object, the column is rotated or vibrated so that new surfaces of the object are always exposed to the gas. Furthermore, in order to generate and sustain high-density plasma at a high pressure of 0.1 to 300 torr, ECR (electron cyclotron resonance) is first generated in the space containing the column under a low vacuum of 1X10-'' to IX10-5 torr. Furthermore, gas is introduced and l X 10-' ~ 3 X 1
The plasma state is changed to a high space pressure of 02 torr, preferably 3 to 30 torr, and the concentration of product gas per unit space in this space is lower than that of the previous ECR.
The concentration is about 102 to 105 times higher than that of CVD method. This makes it possible to form a film of a material that can only decompose or react under such high pressure. Examples are diamond, i-carbon (diamond or carbon coatings with microcrystalline grains), high melting point metals or insulating ceramic coatings.

The formation mechanism of this diamond-containing carbon film is such that during the film formation process, components of the dense parts of the film being formed (e.g., crystalline parts) are left behind, and coarse parts of the film (e.g., amorphous parts) are removed. In other words, it is intended to be carried out while etching is being carried out. The purpose is to form a film having crystallinity on at least a portion of the formed film.

That is, the present invention adds the force of a magnetic field to the conventionally known plasma CVD method using microwaves, and uses the interaction between the electric field and the magnetic field of the microwaves.

However, it does not use ECR (electron cyclotron resonance) conditions that are effective at 1 xto-" to I ~3
Transferred to a region where "hybrid resonance" occurs at a high pressure of 00 torr, and
The coating is formed using high-density, high-energy plasma at a high pressure of 2 torr. Utilizing the high energy state in the hybrid resonance space, for example, a large amount of activated carbon can be generated to produce films with excellent reproducibility, uniform thickness, and homogeneous properties, such as diamond and i-carbon films. This enabled the formation of In addition, since the strength of the applied magnetic field can be changed arbitrarily, it is possible to set resonance conditions not only for electrons but also for specific ions.

Additionally, in addition to the structure of the present invention, after generating high-density plasma through the interaction of microwaves and a magnetic field, in order to maintain a high-energy state even before reaching the object surface, light (e.g. ultraviolet If the active species are continuously irradiated with light (light) and energy is continuously given to the active species, a position 10 to 50 cm away from the region where the microwave electric field is maximum, that is, the high-density plasma generation region (a position where the active state of the reactive gas can be maintained) Also, carbon atoms excited to a high energy state exist, and it is possible to form a diamond or i-carbon film in a larger space. In the present invention, a cylindrical column is disposed in such a space, a film-forming object is disposed within the column, and a film is formed on the surface of the column.

Examples will be shown below to further explain the present invention.

〔Example〕

FIG. 1 shows a microwave plasma CVD apparatus capable of applying a magnetic field used in the present invention.

In the figure, this device includes a plasma generation space (1) that can be maintained in a reduced pressure state, a space for forming a film on an object (3), an auxiliary space (2), and electromagnets (5) and (5') that generate a magnetic field.
and its power source (25), microwave oscillator (4),
A turbo molecular pump (8), a rotary pump (14), a pressure adjustment valve (11), and a cylindrical column (10') constitute the exhaust system.

Film forming object (IOC microwave introduction window (15L gas system (6), (7), water cooling system (18), (1
8″).

First, a thin film forming object (10) is installed in a cylindrical column (10'), and a gate valve (20) is inserted into a plasma generation space (10').
). A cylindrical column made of stainless steel or quartz was used for this column in order to minimize disturbance of microwave and magnetic fields.

This column rotates (
17) I let them. This rotation was performed at a speed of 0.1 to 10 times per minute. Furthermore, although omitted in the drawing, at the same time 1
A slight vibration of 00 to LOKHz was applied to make each object easier to disperse.

As part of the fabrication process, the entire structure was first assembled using a turbo molecular pump (
8), I x 10-6tor by rotary pump
Evacuate to below r. A non-product gas (a gas that does not constitute the decomposition reaction acid solid), such as argon, helium or hydrogen (6), is then introduced into the plasma generation region (1) through the 305 CCM gas system (7), and this pressure is increased to
−'torr. Microwaves with a frequency of 2.45 GHz and a strength of 500 W are applied from the outside. Apply a magnetic field of about 2 Gauss from magnets (5) and (5'), and perform ECR
The high-density plasma that meets the conditions is transferred to the plasma generation space (1
).

, non-product gas or electrons with higher energy than the second high-density plasma region pass through the column (10') (22)
Then, reach the surface of the object (10) in the column and clean the surface. Next, while introducing this non-product gas, a gas is added from the gas system (7), especially a product gas (a gas constituting the post-decomposition/reaction gas), such as a carbide gas (acetylene (
C2)12), ethylene (CJ4) or methane (CH
4) etc.) at a flow rate of 2005 CCH. Then, while maintaining the already generated plasma state, the pressure in the space is changed to a pressure of 0.1 XIF' to 3 X10'' torr, preferably 0.3 to 30 torr, for example 10 torr. As a result, the concentration of product gas per unit space can be increased and the film growth rate can be increased. At the same time, the amount of gas surrounding the gas can also be increased. The active concentration of the product gas can be increased while maintaining the state. Carbon atoms excited with high energy are generated, and this carbon is deposited on a large number of objects (10) in the column (10'). diamond or i
- A carbon film is formed.

In Figure 1, the magnetic field is connected to two ring-shaped magnets (5).
A Helmholtz coil method using (5') was adopted. Furthermore, FIG. 2 shows the results of examining the electric and magnetic field intensities for the space (30) divided into four parts.

In FIG. 2 (A), the horizontal axis (X-axis) is the horizontal direction of the space (30) (outflow direction of reactive gas), and the vertical axis (R-axis)
indicates the diameter direction of the magnet. The curves in the drawings indicate equipotential surfaces of the magnetic field. The number shown on the line indicates the strength of the magnetic field obtained when the magnet (5) is about 2000 Gauss. When the strength of the magnet (5) is adjusted, in a space (within 875 Gauss ± 185 Gauss) having an interaction between the electrodes and the magnetic field, the line (26) is an isomagnetic scene that produces a hybrid resonance condition of 875 Gauss.

The space (100) that produces this resonance condition is designed to be a region where the electric field is maximum, as shown in FIG. 2(B). The horizontal axis in FIG. 2(B) indicates the direction in which the reactive gas flows, as in FIG. 2(A), and the vertical axis indicates the strength of the electric field (electric field strength).

FIG. 3 is a drawing of equal magnetic fields and equal electric fields of the magnetic field (1)) and electric field (B) in the circular space at the position of the substrate (10) in FIG. As is clear from FIG. 3(B), the electric field can reach a maximum of 25 KV/m.

For comparison, a thin film was formed under the same conditions without applying a magnetic field. The thin film formed on the substrate at that time was a graphite film, and it was extremely important to generate hybrid resonance.

When an electron beam diffraction image of the thin film formed in this example was taken, diamond (single crystal grain) spots were observed along with a halo pattern peculiar to amorphous, indicating that the film was an i-carbon film. As the microwave power was further increased and the formation progressed, the halo pattern gradually disappeared, and at 700 nm or more, the film became a film in which more diamond structures were mixed.

In the method of the present invention, a polycrystalline film of silicon carbide can be formed on a substrate using a silicon carbide gas (methylsilane). It is also possible to flow the boride and the nitride simultaneously to form a boron nitride film, for example, by reacting diborane with nitrogen. Aluminum nitride, aluminum oxide, zirconia, and boron phosphide can also be produced in the same way. The formation of films of high melting point conductors of tungsten, titanium, molybdenum or their silicides on objects can also be produced by decomposition reactions of halides or hydrides of these metals themselves or by reaction of these with silane.

〔effect〕

In the present invention, the pressure does not satisfy the ECR conditions and generates an auxiliary plasma discharge, and the mean free path of the reactive gas that generates hybrid resonance while sustaining this discharge is 0.05~
The basic idea is to change the space to lXl0-' to 3 Xl02 torr, which is several mm, particularly 1 mm or less, and which can sustain a plasma state, and to form a film in a space where "hybrid resonance" conditions are occurring. As a result, the growth rate of the film formed increases, and the reactive gases collide with each other and diverge in all directions, making it possible to form a film even on the side surfaces of objects with uneven surfaces.

By employing the method experimentally discovered by the present invention, it has become possible to produce a film under a wider range of conditions than conventionally produced films having at least a portion of crystallinity. Furthermore, compared to conventional methods, it has become possible to form a uniform thin film on the surfaces of a large number of parts. In particular, it has become possible to form this film-forming object on objects of various shapes such as spheres and rectangular parallelepipeds, such as minute gears, screws, decorative jigs, and the like.

In FIG. 1, the heating means are omitted for the sake of simplification of the drawing. However, it goes without saying that depending on the type of film to be formed, the film may be heated to an optimum temperature from outside using an infrared heater. Also, in the drawings, the gas was made to flow from the side to the left. However, it may be from the left side to the right side, from the top to the bottom, or from the bottom to the top. These should be determined by the size and shape of the object and its star if coating is to be done.

In the present invention, the cylindrical column may be cylindrical or square (hexagonal or hexagonal). A square shape allows the object to turn over as it rotates, making it easier to coat the entire surface of the object.

[Brief explanation of the drawing]

FIG. 1 schematically shows a microwave CVD apparatus using magnetic field/electric field interaction used in the present invention. FIG. 2 shows the magnetic field and electric field characteristics by computer simulation. Figure 3 shows the characteristics of the magnetic field and electric field at a position where the electric field and magnetic field interact. 1... Plasma generation space 4... Microwave oscillator 5.5''... External magnetic field generator 10... Film forming object 10''... Cylindrical column 22... Gas style

Claims (6)

[Claims] 1. A method for forming a thin film using an apparatus for forming a thin film using interaction between a magnetic field and an electric field, the method comprising: a plasma generation chamber maintained in a reduced pressure state; a magnetic field generation means provided surrounding the generation chamber; and the plasma. A means for supplying microwaves to the generation chamber, and a hybrid resonance space where the electric field strength of the microwave is maximum and has electric field/magnetic field interaction, or a space spaced apart from this where the active state of the reactive gas is maintained. A method for forming a thin film, comprising: disposing a cylindrical column to introduce a reactive gas; disposing a film-forming object within the column; and forming a thin film. 2. In a thin film forming method using a thin film forming apparatus having a plasma generation chamber maintained in a reduced pressure state, a magnetic field generation means provided surrounding the generation chamber, and means for supplying microwave power to the plasma generation chamber, A cylindrical column is arranged so that the reactive gas is introduced into a space where the microwave electric field is maximum and where there is interaction between electric and magnetic fields, or a space where the reactive gas is maintained in an active state separated from this space. a step of arranging a film-forming object in the column; a step of raising the pressure in the plasma generation chamber to generate electron cyclotron resonance; and a step of generating plasma by supplying the magnetic field and microwaves; A method for forming a thin film, comprising the step of sustaining plasma using hybrid resonance through introduction of the plasma, thereby forming a decomposed or reacted reaction product on the surface to be formed. 3. A thin film forming method according to claim 1, characterized in that the cylindrical column is rotated in the outer circumferential direction or is rotated and vibrated to form a film on the entire surface of the film forming object. 4. In claim 1, the frequency of the microwave is approximately 2.45 GHz, and the coating surface is approximately 87 GHz.
A method for forming a thin film, characterized in that the space has a pressure of 5 Gauss and is provided on the opposite side of a means for supplying micro-energy. 5. The method of forming a thin film according to claim 1, wherein the pressure for producing hybrid resonance is 0.1 to 300 torr. 6. The thin film forming method according to claim 2, wherein the pressure for producing hybrid resonance is 0.1 to 300 torr.