JP2717853B2 - Diamond-like thin film, manufacturing method and manufacturing apparatus - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a diamond-like thin film, a method for producing the same, and a production apparatus, and more particularly to a technique for producing an excellent diamond-like thin film without cracks.

Diamond-like thin films produced by the vapor phase method have high hardness, excellent wear resistance, durability, chemical resistance, corrosion resistance, etc., and can be applied to articles of any shape, so one or more of these characteristics Is useful as a protective film for articles that require it, or is considered promising.

(Prior art and its problems) There are various types of diamond-like thin film manufacturing apparatuses by a vapor phase method (for example, "Surface Chemistry" Vol. 5, No. 108 (1984)
Years) pages 108-115, various methods, Japanese Patent Application Nos. 63-59377 (Japanese Patent Application Laid-Open No. 1-234397) and 63-59376 (Japanese Patent Application No. 1-234396)
No.) etc.). The diamond-like thin film is coated on the surface of an article of any shape to be protected, and is widely used as a protective film such as corrosion resistance and abrasion resistance. However, the diamond-like thin films produced by these conventional techniques are susceptible to cracks (cracks) from the periphery when they exceed a certain thickness or a certain hardness, irrespective of the type of the substrate. I can not get the nature On the other hand, if it is thin enough not to crack, wear resistance and the like become insufficient. The reason for this is that the diamond-like thin film causes internal stress to enter the film due to non-uniformity of conditions at the time of film formation, such as high temperature of the substrate, and the internal stress tends to accumulate as the hardness of the film becomes harder. it is conceivable that.

However, at present, no method has been provided for removing such internal stress, preventing cracking, and obtaining a diamond-like thin film having high hardness or sufficient thickness without cracking.

(Object of the Invention) An object of the present invention is to provide an excellent diamond-like thin film having no crack and / or a sufficient thickness, and to manufacture such a diamond-like thin film. It is an object of the present invention to provide a method and an apparatus.

(Summary of Configuration and Effect of Invention) As a result of earnest study, the present inventors have found that internal stress at the peripheral portion of the film has a great effect on the occurrence of cracks. Based on this knowledge, the inventors studied the film forming conditions and the structure of the peripheral part of the film, and found that the peripheral part of the film should be made thinner toward the outer periphery. That is, in the present invention, the peripheral portion of the diamond-like thin film formed on the substrate is tapered toward the outer periphery, and the thickness of the portion where the inclined portion starts is a, and the length b of the inclined portion is It was found that when these dimensions satisfied 100 <b / a <10,000, the problem of cracking could be prevented.

In order to produce a diamond-like thin film that satisfies the above relationship, it was found that a mask provided between the substrate and the grid for controlling the ion flow for forming the diamond-like thin film should be positioned at a certain distance from the surface of the substrate. That is, the present invention also provides a raw material gas supply source capable of producing a low molecular weight hydrocarbon by a low molecular weight hydrocarbon or cracking reaction, ionization means for the gas, and a substrate provided opposite to the ionization means, In a diamond-like thin film manufacturing apparatus comprising a mask member provided between the ionization source and the base and a diamond-like thin film manufacturing method using the apparatus, the distance between the mask member and the base is set to the diamond-like thickness having the dimensional relationship. It is characterized in that it is determined to obtain a thin film.

(Specific Description of the Invention) As briefly described above, the diamond-like thin film of the present invention can be manufactured using the above-described various film forming methods. However, the method of the present invention is a method for producing a diamond-like thin film by ionization vapor deposition. This is because the quality of the produced diamond-like thin film is good and the process is easy to control.

In the ionization deposition method, a hydrocarbon raw material gas or a raw material gas capable of generating a hydrocarbon by decomposition or reaction (here, hydrocarbon is a saturated hydrocarbon such as methane, ethane, and propane, and an unsaturated hydrocarbon such as ethylene, propylene, and acetylene) Source gases that can be decomposed to produce hydrocarbons include alcohols such as methyl alcohol and ethyl alcohol, and ketones such as acetone and methyl ethyl ketone. Is a mixed gas of carbon monoxide, carbon dioxide and hydrogen, etc. The raw material is a rare gas such as helium, neon, argon, or at least hydrogen, oxygen, nitrogen, water, carbon monoxide, carbon dioxide, etc. One kind can be included) by the arc discharge between the cathode and the cathode, and the bombardment due to thermionic emission between the cathode hot filament and the cathode. Ionized by means of emission and the like as an ion current, a method of forming a film of diamond-like carbon film by directing to the substrate to accelerate the flow field,
JP-A-59-174507, JP-A-63-59376 (JP-A-1-23439)
No. 6), Japanese Patent Application No. 63-59377 (Japanese Patent Application Laid-Open No. 1-234397), Japanese Patent Application No. 1-1199 (Japanese Patent Application No. 2-84595), Japanese Patent Application No. 1-15093 (Japanese Patent Application No. 2-96095). As described in Japanese Patent Application Laid-Open No. H10-260, the ionization vapor deposition method does not require the use of a high temperature of 700 ° C. or more as in the past (for example, “Surface Chemistry” Vol. 5, No. 10).
No. 8 (1984) 108-115, various methods), the film forming efficiency is good, and the formed diamond-like film has good surface properties, high hardness, high thermal conductivity, and high refractive index. It is an excellent method, such as no need for finishing surface treatment.

A wide substrate can be fixed by moving the substrate while fixing the ion beam, or conversely by fixing the substrate and deflecting and scanning the ionized hydrocarbon plasma ion beam in a direction substantially perpendicular to the original direction. To form a diamond-like thin film. Such a deflection magnetic field can be formed by using a permanent magnet or an electromagnet that generates a magnetic field in a direction crossing the acceleration direction of the ion flow.
However, regardless of whether the substrate is fixed or mobile,
It is imperative that the periphery of the produced membrane is constructed according to the invention.

The ionization deposition method, which is the basic technology of the present invention, is disclosed in Japanese Patent Application
-59377 (Japanese Patent Application Laid-Open No. 1-234397) and 63-59376 (Japanese Patent Application Laid-Open No. 1-234396), and in Examples of the present invention, a method using the apparatus described therein as a substrate and Use the device.

(Description of Example) Outline of Film Forming Apparatus FIG. 1 shows a preferred example of a film forming apparatus. In the figure, reference numeral 30 denotes a vacuum vessel, 31 denotes a chamber, which is connected to an exhaust system 38, and 10
^It is drawn to a high vacuum of about ^-6 Torr. Reference numeral 32 denotes an electrode provided on the back surface of the base S, and in this case, a voltage Va is applied. A mask 42 having a window for forming the shape of the diamond-like thin film D is provided near the surface of the substrate S. Reference numeral 33 denotes a grid which is maintained at the same potential Va as the electrode 32 and is used to accelerate ions. Reference numeral 34 denotes a hot cathode filament, which is heated by an AC power supply If to generate thermoelectrons and is maintained at a negative potential. Reference numeral 35 denotes a supply port for a hydrocarbon gas as a raw material. A counter electrode 36 is arranged around the filament 34, and applies a voltage Vc to the filament 34. An electromagnetic coil 39 that generates a magnetic field for confining the ionized gas is disposed around the filament 34, the counter electrode 36, and the supply port 35. The current Ic,
A DC power supply of voltage Vc is connected. Therefore Vc, Vd, Va
By adjusting the coil current Ic, the film quality can be changed.

FIG. 3 is a plan view taken along the line AA in FIG. 1. When the shape of the film is rectangular, for example, an array of a plurality of filaments as shown in FIG. Used.

In FIG. 1, a raw material introduction passage for hydrocarbon gas is shown.
37 is provided with a plasma excitation chamber 37 ', which increases the efficiency of the ionizer. For the plasma excitation, for example, microwave, high frequency (RF wave), radiation, ultraviolet light and the like can be used.

Also, as shown in FIG. 2, a part of the configuration of FIG. 3 may be modified and a fixed or variable strength magnet 40 may be disposed above the filament 34 and used for deflecting a plasma-like ion beam. good. The magnetic field strength of the magnet 40 is fixed or variable, and the magnetic field of the magnet is in a direction crossing the traveling direction of the ion flow. In this manner, the deflection angle θ is obtained with respect to desired ions such as CH ₃ ⁺ and CH ₄ ⁺ ions. On the other hand, in the case of fixation, ions whose masses are significantly different from these ions, for example, hydrogen ions, are further bent, and neutral particles and heavy multimeric ions go straight. Therefore, if the mask is arranged in the straight traveling direction, only ions having high crystallinity adhere to the substrate S.

FIG. 4 is an enlarged view of a part of FIG. 1 to show the features of the present invention. Mask between grid 33 and substrate S
42, and the distance C between the mask and the substrate is about 0.5
It is determined in the range of ~ 10mm. This is a value that allows moderate sneak of ions and forms an inclined portion at the edge of a diamond-like thin film that is deposited and grown on a substrate. The dimensional relationship of the inclined portion is such that the film thickness of the portion where the inclined portion starts is a,
When the length b of the inclined portion is set, 100 <b / a <10,000 is satisfied. In addition, as an example of the dimensions of each part, a is about 0.1 to 10 μm, b is about 20 to 20,000 μm, and c is 0.5
B / a can be selected depending on the distance c. The distance between the grid 33 and the substrate is about 2 to 30 mm. b /
If the ratio of a is too small, cracks cannot be prevented, and if this ratio is too large, the film forming speed will be reduced, especially the thickness of the peripheral portion will be reduced, and the hardness of the film will be reduced.

1. Film forming method The film forming method will be described in detail with reference to the apparatus shown in FIG. First, the inside of the chamber 31 is set to a high vacuum up to 10 ^-6 Torr, and a valve of the gas supply passage 37 is operated to supply a predetermined flow rate of methane gas, a mixed gas thereof and hydrogen, or a carrier gas such as Ar, He, Ne or the like. The exhaust system 38 is adjusted while being introduced from each supply port 35 to a predetermined gas pressure, for example, 10 ^-1 Torr. On the other hand, an alternating current If is passed through the hot cathode filament 34 to heat it, and a potential difference Vd is applied between the filament 34 and the counter electrode 36 to form a discharge. The methane gas supplied from the supply port 35 is thermally decomposed and collides with thermoelectrons from the filament to generate positive ions and electrons. This electron collides with another pyrolysis particle. By repeating such a phenomenon under the confinement effect of the magnetic field of the electromagnetic coil, methane gas becomes a positive ion of a pyrolysis substance.

The positive ions are attracted by the negative potential Va applied to the electrode 32 and the grid 33, accelerated toward the substrate S, collide with the substrate, and perform a film forming reaction to form a diamond-like thin film. If desired, a higher quality thin film can be obtained using the fixed magnet described above.

For the conditions such as the potential, current, temperature, etc. of each part, please refer to other well-known materials in the above-cited patent applications and patent publications.

The thickness of the film to be formed is preferably 100 to 10,000 °, and if the thickness is smaller than the above range, the effects such as abrasion resistance are reduced. If the thickness is too large, the effect is not increased and the production time is increased.

Further, the substrate on which the diamond-like film is formed may be cleaned in advance by ultrasonic cleaning with an organic solvent or the like.

 Hereinafter, the present invention will be exemplified.

Example 1 Using the apparatus shown in FIG. 1, a plate-like substrate S was placed in a vacuum chamber 10 and a mask 42 having openings of 10 mm in width and 10 mm in length at various distances of 500 and 1000 μm from the surface thereof. And place
The grid 33 was arranged at a position 6 mm from the substrate S. The distance from the substrate S to the filament was about 40 mm.

After evacuating the vacuum chamber 10 to 10 ^-6 Torr, methane gas was introduced to set the gas pressure at 10 ^-1 Torr, and discharge was caused in the hot cathode filament 34. The magnetic flux density of the electromagnetic coil 19 is 400 gauss,
The substrate voltage Va-300V and the substrate temperature were 200 ° C. An AC current If25A was passed through the filament.

The filament 34 was coil-shaped and had a width of 3 mm and a gap 8 mm between the filament 34 and the counter electrode 36 surrounding the coil.

Under conditions of Vc = 30 V and Vd = −30 V, a diamond-like film having a thickness of 1.0 μm was obtained.

The thickness a of the obtained film and the length b of the inclined portion were measured, and cracks at the peripheral portion were observed. Table 1 shows the results.

Was.

(Effects) As is clear from Table 1, the diamond-like thin film formed on the substrate of the present invention has a peripheral inclined portion having a dimension of 100 <b / a.
It can be seen that when <10000 is satisfied, cracking is prevented, and in order to satisfy this condition, it is better to position the mask position c at 0.5 to 10 mm.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of the apparatus for producing a diamond-like thin film of the present invention, FIG. 2 is a cross-sectional view showing another example of the apparatus for producing a diamond-like thin film, and FIG. FIG. 4 is a perspective view and FIG. 4 is a partially enlarged view of the apparatus shown in FIG. 1 showing a main part of the present invention.

Claims (5)

(57) [Claims] 1. A diamond-like thin film formed on a substrate, wherein a peripheral portion thereof is tapered toward the outer periphery, and a film thickness at a portion where the inclined portion starts is a, and a length of the inclined portion is a. A diamond-like thin film characterized in that these dimensions satisfy 100 <b / a <10,000, where b. 2. A source gas supply source capable of producing a low molecular weight hydrocarbon or a low molecular weight hydrocarbon by decomposition or reaction, ionization means for said gas, a base provided opposite to said ionization means, It comprises a mask member provided between the ionization source and the substrate, and the mask member has a peripheral portion of a diamond-like thin film formed on the substrate from the surface of the substrate, and has the following formula: 100 <b / a < A diamond-like thin film manufacturing apparatus characterized by being disposed at a distance c which satisfies 10,000 (where a is the film thickness of a portion where the tapered inclined portion of the periphery of the diamond-like thin film starts, and b is the length of the inclined portion). . 3. The method according to claim 1, wherein the distance c is 0.5 to 10 mm. 4. The apparatus for manufacturing a diamond-like thin film according to claim 2, wherein a hydrocarbon raw material gas or a raw material gas capable of generating a hydrocarbon by decomposition or reaction is introduced, and this is ionized by heat and an electric field. A method for producing a diamond-like thin film, comprising forming an ion beam and depositing it on the surface of a substrate to form a diamond-like thin film. 5. The method according to claim 4, wherein the ion beam is deflected by a deflecting magnetic field in a direction perpendicular to the direction of the original ion beam.