JPH01100277A - Curved plate stuck with rigid carbonaceous film, manufacture and manufacturing device thereof - Google Patents

Abstract

PURPOSE:To obtain a curved plate stuck with a rigid carbonaceous film which is uniform and excellent in adhesion of the film by bringing plasma obtained by activating a gaseous raw material into contact with a base plate which is arranged between positive and negative electrodes having a curved surface correspondent to the curved surface of the base plate. CONSTITUTION:A base plate (curved plate) 2 is arranged to a negative electrode 11 having a curved surface correspondent to the curved surface of the base plate 2. A positive electrode 13 having the curved surface correspondent to this base plate 12 is arranged so as to keep equidistance for the negative electrode 11. Then plasma obtained by activating a gaseous raw material between both electrodes 11, 13 is brought into contact with the base plate 12. A uniform rigid carbonaceous film is formed on the surface of the base plate (curved plate) 12. This curved plate stuck with the rigid carbonaceous film is used for a diaphragm for a speaker, a radio cone and a parabolic antenna, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application J This invention relates to a curved plate having a uniform film containing diamond or diamond-like carbon or both on the surface of the curved plate with a hard carbon film attached thereto, a method for manufacturing the same, and The present invention relates to an apparatus for manufacturing a carbon film-attached curved plate.

[Prior art and its problems] In recent years, research has been actively conducted in various fields on the production of hard carbon films, that is, thin films of diamond or diamond-like carbon (hereinafter, diamond-like carbon may be abbreviated as DLC). , the amount of reports regarding this technology is steadily increasing.

Generally, when manufacturing a DLC thin film using a high frequency plasma CVD apparatus, a substrate is placed on the side of a high frequency application electrode (hereinafter referred to as RF main electrode), and a diamond G film is formed on the substrate.

Figure 2 schematically shows this relationship.
2 is the substrate, 3 is the counter electrode (earth electrode), and S is the RF power source. Therefore, this type of apparatus is usually referred to as parallel plate type high frequency plasma CvD.

Various technologies have also been proposed for manufacturing speaker diaphragms or speaker cones using such CvD technology.For example, in speaker diaphragms, the substrate surface is coated with a diamond film or an amorphous carbon film. technology (Japanese Unexamined Patent Publication No. 59-143499),
A more extreme technique is the use of a speaker diaphragm made of a diamond film or amorphous carbon (Japanese Patent Laid-Open No. 59-143
498 (Japanese Unexamined Patent Publication No. 161200/1982), or a technology for an acoustic diaphragm obtained by forming a DLC film on a thin film made of silicon or boron (Japanese Patent Application Laid-Open No. 161200/1983).

However, in the case of the first two, what type of CVD is actually used? It is not always clear what kind of material or shape the board is used for, but given that the explanation is extremely general, it is generally used in any case. This is thought to be caused by the parallel plate type CVD equipment.

In the latter case, silicon or boron S! However, it is described that a DLC film is formed on the DLC film.

In this case as well, it is considered that a normal parallel plate type CVD apparatus is used.

By the way, considering the situation in which a diamond thin film or DLC [or both] is formed on a curved substrate for use in a 99 speaker using an ordinary parallel plate and IcVD device, the method indicated by the arrow in Fig. 3 The plasma gas advances as follows.

However, since the shape of the plasma gas reaching surface is convexly curved, a difference appears in the reaching density per unit projected area of the plasma gas, and a difference in density appears on the inclined surface, resulting in a diamond thin film or DLC
[Alternatively, both methods have a major drawback in that the film is deposited in stripes on the surface of the substrate as shown in FIG. That is, in conventional speaker diaphragms, the diamond film or amorphous carbon film was non-uniformly adhered to the surface of the substrate.

If this condition is ignored and used as an acoustic product, the thin film that has been formed may easily peel off from the substrate because the state of the film is not uniform. Due to the non-uniformity of the signal, it tends to exhibit an unfavorable acoustic tendency.

This invention was made in order to solve the above-mentioned problems, and it is possible to uniformly apply a diamond thin film or DLClgl, or both, to a curved substrate surface, where it has been difficult to uniformly deposit a film in the past. The purpose of the present invention is to provide a hard carbon film-attached curved plate formed by uniformly and densely forming a n film on the surface of the curved plate, and to provide a method for manufacturing the hard carbon film-attached curved plate and a manufacturing apparatus therefor. It is something that exists.

[Means for Solving the Problems J] The structure of the first invention for achieving the above-mentioned object is characterized in that a hard carbon film of uniform thickness is formed on the surface of a curved plate. The structure of the second invention is a curved plate with a hard Jti carbon film attached thereto, in which a curved substrate is arranged on a negative electrode having a curved surface corresponding to the curved surface of the substrate, and a curved plate having a curved surface corresponding to the curved surface of the negative electrode is arranged. Plasma obtained by activating source gas between the negative electrode and the positive electrode, in which a positive electrode having a curved surface is disposed facing each other with unevenness so as to be equidistant from the curved surface of the negative electrode, is A method of manufacturing a curved plate with a hard carbon film attached thereto, characterized in that the curved plate is brought into contact with a substrate, and the configuration of the third invention includes: a negative electrode having a curved surface portion that corresponds to the curved state of the substrate and on which the substrate is placed; A positive electrode having a curved surface portion curved corresponding to the curved surface of the negative electrode is arranged such that the curved surfaces face each other with unevenness and the curved surface of the negative electrode and the curved surface of the positive electrode maintain an equal distance. A raw material gas introducing means for supplying raw material gas is provided between the negative electrode and the positive electrode, and a plasma gas generated between the negative electrode and the positive electrode opposite thereto is supplied to the negative electrode. This is an apparatus for manufacturing a curved plate having a hard carbon film attached thereto, which is characterized in that it is capable of contacting a substrate placed on an electrode.

This invention will be explained in further detail.

The principle of this invention is that diamond and/or diamond-like carbon (
Hereinafter, this will be abbreviated as hard carbon. ) M is formed uniformly, and the principle method is to form a negative electrode having a curved surface corresponding to the curved surface of the curved substrate, and a positive electrode having a curved surface corresponding to the curved surface of the negative electrode. The curved surfaces of the negative electrode and the curved surface of the positive electrode that face each other are arranged to face each other, and the curved surface of the negative electrode and the curved surface of the positive electrode are kept at an equal distance, and between these two facing electrodes, the raw material gas is activated and obtained. The generated plasma is brought into contact with the surface of the substrate, and as a result, a hard carbon film-attached curved plate is obtained in which a hard carbon film is uniformly formed on the surface of the curved substrate.

The shape of the substrate is arbitrary and may be of various shapes, for example, the shape of the substrate may be a hemisphere, such as a hollow sphere with half cut out, or any part thereof cut out. shape, semi-ellipsoidal sphere shaped like a hollow ellipsoid with half cut off in the major axis direction or minor axis direction, or an arbitrary part cut off, an n-sided pyramid such as a truncated triangular pyramid shape and a truncated quadrangular pyramid shape. Examples include a trapezoidal shape (n is an integer), a so-called cylindrical shape obtained by cutting a cylindrical body at an arbitrary plane parallel to the center line of the cylindrical body, and a parabolic shape whose outer peripheral surface is a paraboloid. . Note that since the substrate in the present invention is a plate-shaped body, the substrate usually has a convexly curved outer surface and a concavely curved inner peripheral surface corresponding to the convexity.

The shape of the substrate to be used is determined depending on the use of the substrate on which the hard carbon film is formed.

In this invention, when a diamond film is formed on the convex surface of a hemispherical substrate, which is often used,
This is because this can be used as a speaker cone. Furthermore, if the antenna is to be used as a parabolic antenna, it is preferable to use a parabolic shaped substrate.

There are no particular restrictions on the material of the substrate as long as it has sufficient heat resistance to withstand contact with plasma; for example, metals such as aluminum, titanium, tungsten, molybdenum, cobalt, and chromium, semimetals such as silicon, Oxides, nitrides and carbides of the metals and metalloids, alloys of the metals, A1703-Fe series, TiC-Ni series, Ti
Examples include cermets such as C-Co, TiC-TiN, and B4C-Fe, as well as various glasses and ceramics. In addition, heat-resistant synthetic resins may also be used depending on the case.

If a hard carbon film is formed on the surface of a substrate according to the method of this invention or by the apparatus of this invention, and the substrate is used as a diaphragm for an acoustic speaker, the material of the substrate has excellent acoustic characteristics. It is preferable to use titanium, aluminum, alumina, titanium carbide, or the like.

In addition, in order to improve the adhesion of the hard carbon film to the substrate surface, an intermediate film made of silicon, silicon carbide, titanium carbide, etc. is preliminarily applied to the surface of the substrate on which the hard carbon film is to be formed. It may be formed with a thickness of 3JLm.

Next, in this invention, once the shape of the substrate is determined, the shapes of the negative electrode and the positive electrode can be determined. This is because the substrate must be placed on the negative electrode, and the opposing surfaces of the negative and positive electrodes must be equidistant from each other.

Therefore, if the substrate has a hemispherical shape and a hard carbon film is formed on its convex outer surface, the negative electrode also has a convex curved surface portion that is a hemispherical convex curved surface. Then, this hemispherical convex negative polarization surface portion becomes a portion where the hemispherical substrate is placed a.

If the substrate has a parabolic shape and a hard carbon film is formed on the inner periphery of the concave paraboloid, the negative electrode will also be the same. It has a concave curved surface with a concave parabolic outer peripheral surface.

Similarly, if the substrate has various other shapes and a hard carbon film is to be formed on its outer surface, a convex or concave shape having the same outer surface as that of the negative electrode substrate may be used. It has a curved surface. Note that the curved shape of the board (
To be precise, it is sufficient that the curved shape of the surface of the substrate facing the negative electrode substantially corresponds to the curved shape of the negative electrode, and it is not necessary that they exactly match without any difference.

On the other hand, the shape of the positive electrode has an inverse relationship between the unevenness and the shape of the negative electrode.

That is, if the negative electrode has a curved shape with a convex hemisphere, for example, the positive electrode has a curved shape with a concave hemisphere. If the negative electrode has a concave curved shape with a parabolic inner circumferential surface, the positive electrode has a
It has a convex curved shape with a parabolic outer peripheral surface. Even if the negative electrode has a curved surface of another shape, the positive electrode concave curved surface has a shape corresponding to the curved surface of the negative electrode.

Since the curved surface of the negative electrode and the curved surface of the positive electrode have corrugated shapes that correspond to each other, an electric field is generated between the negative electrode and the positive electrode in a direction perpendicular to the curved surface of the negative electrode. .

In addition, in this invention, a bias voltage may be applied to the positive electrode and the negative electrode. In that case, the electrode with the higher potential is the positive electrode.

The apparatus according to the present invention includes source gas introducing means for supplying source gas between the negative electrode and the positive electrode.

The raw material gas introducing means may have any structure or type as long as it can introduce the raw material gas between the negative electrode and the positive electrode, but it should be used so that uniform plasma is generated between the two electrodes. If there is, as shown in Figure 1, the positive electrode 1
A plurality of gas ejection ports 14 opened in a −-shape are provided on the curved surface facing the negative electrode 11 in 3, and the gas ejection ports 1
It is preferable to eject the raw material gas between the circular electrodes 11 and 13.

In FIG. 1, the raw material gas is in the cavity on the back side of the curved surface which is the positive electrode 13! 7, the gas introduction pipe is introduced from the 1st, and then the gas outlet! It erupts from 4.

Examples of raw material gases include alkane hydrocarbons such as methane, ethane, propane, butane, pentane, and hexane, alkenes hydrocarbons such as ethylene, propylene, butene, pentene, and butadiene, and alkynes hydrocarbons such as acetylene. , aromatic hydrocarbons such as benzene, toluene, xylene, indene, naphthalene, and phenanthrene; cycloparaffins such as cyclopropane and cyclohexane; and cycloolefins such as cyclopentene and cyclohexene. Furthermore, halides of the various compounds mentioned above can also be used as the raw material gas.

In addition, oxygen-containing carbon compounds such as carbon oxide, carbon dioxide, methyl alcohol, and ethyl alcohol, and nitrogen-containing carbon compounds such as methylamine, ethylamine, and aniline can also be used.

Although not used alone, it can also be effectively used with gasoline, kerosene, turpentine oil, pine oil, heavy oil, gear oil, and cylinder oil.

Note that this carbon source may be one selected from the above-mentioned group, but it is also possible to use a suitable combination of two or more types as required.

The raw material gas is directly supplied between the two electrodes by the raw material introducing means, but it may also be introduced using a carrier gas.

The carrier gas is not particularly limited as long as it can stably generate plasma between the two electrodes and maintain it for a long time; for example, hydrogen gas, helium gas,
Neon gas, argon gas, krypton gas, xenon gas, nitrogen gas, etc. can be used.

The carrier gas is one or two selected from the above.
More than one species can be used in combination.

The activity of the raw material gas can be determined by conventionally known methods, such as applying a DC voltage between electrodes, applying high frequency between electrodes, or applying microwaves between electrodes. Among these, an activation method in which high frequency is applied between the electrodes is preferred.

For an example of the activity of the raw material gas, referring to FIG. 1, the inside of the reaction chamber 15 which has been reduced in pressure is evacuated, and a curved negative electrode 11 and a positive electrode 13 arranged opposite to each other with unevenness on the curved surface of the negative electrode 11 are formed. The raw material gas is ejected from the gas ejection port 14 between the two. A high frequency is applied to the negative electrode, the positive electrode is grounded, and the substrate 12 is heated to a predetermined temperature.

Under such conditions, the raw material gas becomes plasma due to plasma discharge between the positive and negative electrodes.

The generated plasma comes into contact with the substrate 12 placed on the curved surface of the negative electrode 11, and a hard carbon film is formed on the surface of the substrate 12.

As a reaction condition for activating the raw material gas by, for example, plasma CVD method, the pressure is 10-8 to 103 Torr.
r, preferably 10-4 to 102 Torr.

If this pressure is lower than 10-8 Tart,
The rate of formation of the hard carbon film may be significantly reduced, while when pressures higher than 103 Tart are used, no hard carbon film may be formed.

Further, the reaction temperature is from room temperature to 1000°C, preferably from room temperature to about 900°C.

If this temperature is lower than room temperature, the growth rate of the hard Jt1 carbon film may slow down significantly;
Even if a temperature exceeding 00° C. is used, the effect commensurate with the amount of energy used will no longer be obtained.

In this invention, it depends on how the conditions are set.

A diamond film, a diamond-like carbon film, or a mixed film of diamond and diamond-like carbon is uniformly formed on the surface of the substrate as a hard carbon film.

The thickness of the hard carbon film formed on the surface of the substrate cannot be specified depending on the intended use of the board with the hard carbon film, but if the board with the hard carbon film is used as an acoustic speaker diaphragm, , the thickness of the hard carbon film is 1,090
It is desirable that the hard carbon film has a thickness of A or more, preferably 3,000A to 304m.This is because a hard carbon film with a thickness of 1.00OA or more has good acoustic characteristics.

[Example J Hereinafter, the structure and effects of the present invention will be explained in more detail by specifically showing Examples and Comparative Examples.

(Example 1) A negative electrode 11 with a diameter of 45 amφ as shown in FIG.
A titanium substrate 12 (diameter of the convex portion 251111φ, height 10 IIm, thickness of the substrate 35
A speaker cone of 4 m) was set.

On the other hand, a concavely curved positive electrode was set at a distance of 10 mm from the convexly curved surface of the negative electrode so as to face the concave and convex surface of the negative electrode, and a hard carbon film was formed under the following conditions.

Synthesis method: RF plasma CVD method 13.56 Hz, internal electrode reaction gas: pure methane, flow rate 205 OON RF output crab s
oo w Pressure: 0. I Torr d: 10 ■ layer DC bias: 400V Substrate temperature = 100°C The hard carbon film formed on the speaker cone has a thickness of 5,000 pm and its adhesion is good, and the film does not close. Not recognized, and there is 1 hard carbon on the surface of the board! : The film was formed uniformly. In addition, the formation rate of the hard carbon film at this time was 70 to 100 A/min.

Separately, the Knoop hardness of a hard carbon film formed on a silicone substrate under the same conditions as above was 2.420 kg/
mm2, and when Raman spectrum analysis was performed, the Raman spectrum of this hard carbon film was similar to that of the well-known DLCl.
It matched that of gi.

(Comparative Example) In the example, formation of a hard carbon film was attempted in the same manner as in the previous example under all the same conditions except that flat electrodes arranged parallel to each other were used.

As a result, on the convex curved surface of the substrate, formation of a hard carbon film clearly in the form of stripes as shown in FIG. 4 was observed. Moreover, peeling was observed in a part of this hard carbon film, and it became powder-like.

[Effects of the Invention] According to the present invention, ■ Since the hard carbon film is uniformly formed on the surface of the curved substrate, it is possible to provide a curved substrate with a hard carbon film having excellent film adhesion; When this curved substrate with a hard carbon film is used in audio equipment such as speaker diaphragms and speaker cones, it exhibits excellent acoustic properties, and when used in communication equipment such as parabolic antennas, it exhibits excellent weather resistance and corrosion resistance. ■ It is possible to coat a hard carbon film with high uniformity. ■ The thin film is uniform so no peeling occurs. [Co., Ltd.]
■ The substrate is placed on an electrode that has a curved surface that corresponds to the curved surface of the substrate, which allows for high-hardness coating, resulting in close contact between the substrate and the electrode, resulting in good thermal conductivity. Thus, it is possible to provide a method for manufacturing a curved board with a hard carbon X film attached thereto, and an apparatus for manufacturing the same, in which the substrate temperature can be sufficiently raised and the temperature of the substrate can be easily controlled.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram of a CVD apparatus constructed according to the present invention, Fig. 2 is a basic conceptual diagram of a plasma CVD apparatus, Fig. 3 is a conceptual diagram of a conventional apparatus, and Fig. 4 is a conceptual diagram of the apparatus of Fig. 3. FIG. 3 is a front view showing a state in which a hard carbon film is formed on a speaker cone using the speaker cone. l: negative electrode, 2: substrate, 3: positive electrode, 11: positive electrode, 1
2: Substrate, 13: Positive electrode, 14 = Gas supply port. Patent applicant: Idemitsu Petrochemical Co., Ltd. Agent
Patent Attorney Naoki Fukuso '4 Figure 1 Figure 2 Figure 3 Procedural Amendments dated 15th October 1986

Claims (1)

[Scope of Claims] (1) A hard carbon film-attached curved plate, characterized in that a hard carbon film of uniform thickness is formed on the surface of the curved plate. (2) The hard carbon film-attached curved plate according to claim 1, wherein the hard carbon film-attached curved plate is a diaphragm for a speaker. (3) The hard carbon film-attached curved plate according to claim 1, wherein the hard carbon film-attached curved plate is a speaker cone. (4) The hard carbon film attached curved plate according to claim 1, wherein the hard carbon film attached curved plate is a parabolic antenna. Board. (5) A curved substrate is placed on a negative electrode having a curved surface corresponding to the curved surface of the substrate, and a positive electrode having a curved surface corresponding to the curved surface of the negative electrode is placed equidistant from the curved surface of the negative electrode. The plasma obtained by activating the raw material gas between the negative electrode and the positive electrode, which are arranged facing each other with the unevenness,
A method for manufacturing a curved plate with a hard carbon film attached thereto, the method comprising bringing the board into contact with the substrate. (6) the substrate is a convex plate;
The negative electrode has a convex curved surface portion on which the substrate, which is the convex plate, is placed, and the positive electrode has a concave curved surface portion corresponding to the convex curved surface portion. A method for manufacturing a hard carbon film-attached curved plate according to Scope 5. (7) The substrate is a hemispherical convex plate, and the negative electrode is
Claim 5, wherein the positive electrode has a convex curved surface portion on which a substrate, which is a hemispherical convex plate, is placed, and the positive electrode has a concave curved surface portion corresponding to the circular convex curved surface portion. The method for manufacturing a hard carbon film-attached curved plate according to item 1 or 6. (8) Claim 5, wherein the substrate is titanium.
A method for manufacturing a hard carbon film-attached curved plate according to any one of items 1 to 7. (9) The method for manufacturing a curved plate with a hard carbon film attached thereto according to any one of claims 5 to 8, wherein the substrate is coated with silicon, silicon carbide, or titanium carbide on its surface. (10) A negative electrode having a curved surface portion corresponding to the curved state of the substrate and on which the substrate is placed, and a positive electrode having a curved surface portion curved corresponding to the curved surface of the negative electrode, the curved surfaces of which are uneven. Providing a raw material gas introduction means for supplying raw material gas between the negative electrode and the positive electrode, which are arranged so that the curved surfaces of the negative electrode and the curved surface of the positive electrode face each other and maintain an equal distance; A manufacturing apparatus for a hard carbon film-attached curved plate, characterized in that a plasma gas generated between the negative electrode and the positive electrode facing the negative electrode can come into contact with a substrate placed on the negative electrode. (11) The substrate is a convex plate, the negative electrode has a convex curved surface portion on which the convex substrate is placed, and the positive electrode has a concave shape corresponding to the convex curved surface portion. An apparatus for manufacturing a hard carbon film-attached curved plate according to claim 10, which has a curved surface portion. (12) The substrate is a circular convex plate, the negative electrode has a circular convex curved surface portion on which the substrate, which is a circular convex plate, is placed, and the positive electrode is arranged on the circular convex curved surface portion. Claim 1 having a concave curved surface portion corresponding to
An apparatus for manufacturing a hard carbon film-attached curved plate according to item 0 or 11. (13) The hard carbon film-attached curved plate according to any one of claims 10 to 12, wherein the raw material gas introducing means is provided with a gas jet port opened in a curved surface portion of the positive electrode. manufacturing equipment.