JP2016098383A - Plasma reaction device - Google Patents

Abstract

A plasma reaction apparatus capable of accelerating processing of a substrate using plasma with a simple configuration. A high-frequency plasma CVD apparatus 1 as an example of a plasma reaction apparatus includes a reaction chamber 2 for introducing a raw material gas, and an anode electrode 6 and a cathode that are formed in a flat plate shape and are opposed to each other. An electrode portion 5 having an electrode 7 and disposed inside the reaction chamber 2; a cylindrical electrode 10 which is installed on a facing surface 7a of the cathode electrode 7 together with the base material 11 and surrounds the periphery of the base material 11; And a high frequency power source 9 for generating the voltage at the electrode unit 5. The high-frequency plasma CVD apparatus 1 converts the hydrocarbon gas into plasma by high frequency and activates the chemical reaction of the hydrocarbon gas, so that the base material 11 is installed in the reaction chamber 2 and surrounded by the cylindrical electrode 10. A DLC film is formed on the surface. [Selection] Figure 1

Description

  The present invention relates to a plasma reactor.

  Diamond-like carbon (DLC) film has high hardness, is excellent in biocompatibility, wear resistance, corrosion resistance, etc., and has physical and chemical stable characteristics. Applications in various fields such as industrial fields are expected. For example, it can be expected to extend the product life by coating the surface of a cutting tool, a mold, a building member or the like with a DLC film. In addition, it is expected that the biocompatibility of these medical devices can be improved by coating medical devices such as artificial joints with a DLC film.

  The DLC film can be formed on the surface of the substrate by using a plasma reactor such as a high-frequency plasma chemical vapor deposition (CVD) apparatus. In the DLC film formation method using a plasma reactor, it is desired to improve the adhesion between the DLC film to be formed and the substrate. For example, an intermediate layer mainly composed of silicon is formed on the substrate. Thus, a method of forming a DLC film on the intermediate layer has been proposed (see, for example, Patent Documents 1 and 2).

JP 2000-178737 A JP 2010-106311 A

  However, in the conventional DLC film deposition method described in Patent Documents 1 and 2, it is necessary to form an intermediate layer, which causes problems such as a complicated deposition process and increased processing time. There is. Therefore, it is possible to form a DLC film using a plasma reaction with a simple structure so that a DLC film can be formed quickly and an adhesion of the formed DLC film can be improved without providing an intermediate layer. It is desirable to be able to promote.

  By the way, in the conclusion of a plasma reactor that processes the surface of a substrate using a plasma reaction gas, various processing techniques such as reactive ion etching are applied in addition to the above DLC film formation. ing. Even in these various processing methods using a plasma reactor, there is room for further improvement in that the processing of a substrate using plasma is promoted even with a simple configuration, similar to the DLC film forming method described above. It was.

  This invention is made | formed in view of the above, Comprising: It aims at providing the plasma reactor which can accelerate | stimulate the process of the base material using a plasma by simple structure.

  In order to solve the above problems, a plasma reaction apparatus according to the present invention includes a reaction chamber for introducing a reaction gas, and an anode electrode and a cathode electrode that are formed in a flat plate shape and are provided with opposing surfaces facing each other, An electrode part disposed inside the reaction chamber, a cylindrical electrode installed together with a base material on the opposite surface of the cathode electrode, surrounding the periphery of the base material, and a power source for generating electromagnetic waves in the electrode part, The electromagnetic wave is generated between the anode electrode and the cathode electrode of the electrode unit by the power source, and the reaction gas introduced into the reaction chamber is converted into plasma by the electromagnetic wave, thereby generating the plasma. The surface of the base material, which is installed in the reaction chamber and surrounded by the cylindrical electrode, is processed using the reacted reaction gas.

  In the plasma reaction apparatus, the reaction gas introduced into the reaction chamber is a raw material gas, and the raw material gas is turned into plasma by the electromagnetic wave, thereby activating a chemical reaction of the raw material gas, It is preferable to form a thin film on the surface of the substrate that is installed in the reaction chamber and surrounded by the cylindrical electrode.

  In the plasma reaction apparatus, the thin film is preferably a diamond-like carbon (DLC) film.

  Further, in the above plasma reaction apparatus, the electrode unit is configured such that, in the reaction chamber, the anode electrode is disposed on the upper side in the vertical direction, the cathode electrode is disposed on the lower side in the vertical direction, and the cylindrical electrode Is preferably placed on the facing surface of the cathode electrode.

  In the plasma reaction apparatus, it is preferable that a plurality of the cylindrical electrodes are provided on the facing surface of the cathode electrode of the electrode portion.

  In the above plasma reactor, in the state where the cylindrical electrode is installed on the cathode electrode, the height dimension of the cylindrical electrode is the distance between the anode electrode and the cathode electrode. On the other hand, it is preferably 12.5% to 50%.

  In the plasma reaction apparatus, in a state where the cylindrical electrode is installed on the cathode electrode, a cross-sectional area of the cylindrical electrode is 1% with respect to an area of the facing surface of the cathode electrode. It is preferable.

  Since the plasma reactor according to the present invention can increase the plasma intensity inside the cylindrical electrode, that is, around the base material by installing the cylindrical electrode surrounding the base material, it has a simple configuration. Thus, it is possible to promote the processing of the base material using plasma.

FIG. 1 is a schematic diagram showing a schematic configuration of a high-frequency plasma chemical vapor deposition (CVD) apparatus as an example of a plasma reaction apparatus according to an embodiment of the present invention. FIG. 2 is an enlarged view of the cathode electrode and the cylindrical electrode in FIG. FIG. 3 is a plan view of the cathode electrode and the cylindrical electrode shown in FIG. FIG. 4 is a plan view showing an example of a modification of the cylindrical electrode. FIG. 5 is a diagram showing the deposition rate of the formed DLC film for Example 1 and Comparative Example 1. FIG. 6 is a diagram showing the chemical composition evaluation of the surface of the SUS substrate before and after the film formation process is performed in the first embodiment. FIG. 7 is a diagram showing the structural evaluation of the thin film formed in Example 1. FIG. 8 is a diagram showing the results of evaluating the adhesion of the DLC film in Examples 2 to 4 and Comparative Example 2. FIG. 9 is a diagram showing film structure evaluation by Raman spectroscopy in Examples 2 to 4 and Comparative Example 2.

  Hereinafter, an embodiment of a plasma reactor according to the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated.

[Embodiment]
The plasma reactor uses the plasma-converted reaction gas by generating electromagnetic waves between parallel plate electrodes installed in the reaction chamber and converting the reaction gas introduced into the reaction chamber into plasma using the electromagnetic waves. And an apparatus for processing the surface of the base material installed in the reaction chamber. In the present embodiment, a high frequency plasma CVD apparatus 1 will be described as an example of such a plasma reaction apparatus.

  With reference to FIGS. 1-3, the structure of the high frequency plasma CVD apparatus 1 which concerns on this embodiment is demonstrated. FIG. 1 is a schematic diagram showing a schematic configuration of a high-frequency plasma chemical vapor deposition (CVD) apparatus as an example of a plasma reaction apparatus according to an embodiment of the present invention. FIG. 2 is an enlarged view of the cathode electrode and the cylindrical electrode in FIG. FIG. 3 is a plan view of the cathode electrode and the cylindrical electrode shown in FIG. In the following description, the vertical direction in FIG. 1 is expressed as “vertical direction”, the anode electrode 6 side in FIG. 1 is expressed as “upper direction” in the vertical direction, and the cathode electrode 7 side is expressed in “down direction” in the vertical direction. "Side".

  A high-frequency plasma CVD apparatus 1 shown in FIG. 1 is an apparatus that forms a surface of a substrate 11 by a high-frequency plasma CVD method. The high-frequency plasma CVD method is a kind of chemical vapor deposition that uses plasma and is a kind of vapor deposition technique for forming thin films of various substances. The high-frequency plasma CVD method is characterized in that the raw material gas is turned into plasma by applying a high frequency in order to activate a chemical reaction. The high-frequency plasma CVD apparatus 1 activates the chemical reaction of the raw material gas by converting the raw material gas introduced into the reaction chamber 2 into plasma by the high frequency generated between the parallel plate electrodes (electrode part 5 in FIG. 1). Thus, a thin film can be formed on the surface of the substrate 11 installed in the reaction chamber 2. In the present embodiment, the high-frequency plasma CVD apparatus 1 will be described by taking as an example a film forming method for forming a diamond-like carbon (DLC) film on the surface of the base material 11.

  As shown in FIG. 1, the high-frequency plasma CVD apparatus 1 includes a reaction chamber 2, an electrode unit 5, a matching unit 8, a high-frequency power source 9 (power source), and a cylindrical electrode 10.

The reaction chamber 2 (chamber) is filled with the base material 11 and forms a sealed space for forming a DLC film on the surface. The reaction chamber 2 has an inlet 3 and an outlet 4. The introduction port 3 supplies a raw material gas (reaction gas) into the reaction chamber 2. When a DLC film is formed, a hydrocarbon gas such as ethylene (C ₂ H ₄ ), methane (CH ₄ ), propane (C ₃ H ₈ ) or the like is used as a raw material gas from the inlet 3 through the reaction chamber 2. To be supplied. The discharge port 4 exhausts the air in the reaction chamber 2. For example, a vacuum pump is connected to the discharge port 4, and the reaction chamber 2 is evacuated through the discharge port 4 by this vacuum pump.

  The electrode unit 5 is installed in the internal space of the reaction chamber 2. The electrode unit 5 includes a plate-like anode electrode 6 and a cathode electrode 7. The anode electrode 6 and the cathode electrode 7 are arranged substantially in parallel in the reaction chamber 2. The anode electrode 6 and the cathode electrode 7 are provided with facing surfaces 6a and 7a that face each other. The opposing surfaces 6a and 7a have substantially the same area, and are both substantially circular. The facing surfaces 6a and 7a are arranged so as to substantially overlap when viewed from the vertical direction. The anode electrode 6 is grounded, and the cathode electrode 7 is connected to a high frequency power source 9 via a matching unit 8.

  In the electrode section 5, the anode electrode 6 is disposed on the upper side in the vertical direction and the cathode electrode 7 is disposed on the lower side in the vertical direction in the reaction chamber 2. That is, the anode electrode 6 is disposed with the facing surface 6a facing vertically downward, while the cathode electrode 7 is disposed with the facing surface 7a facing vertically upward. In the present embodiment, the base material 11 on which the DLC film is formed is placed on the facing surface 7a of the cathode electrode 7 arranged on the lower side in the vertical direction.

  The high frequency power supply 9 is a power supply device that outputs a high frequency (electromagnetic wave). The high frequency output from the high frequency power supply 9 is applied to the cathode electrode 7 via the matching unit 8. Thereby, the electrode part 5 can generate a high frequency (electromagnetic wave) between the opposing surface 6 a of the anode electrode 6 and the opposing surface 7 a of the cathode electrode 7. The high frequency power supply 9 outputs a high frequency of 13.5 MHz, for example.

  The cylindrical electrode 10 is a metal member made of stainless steel or the like formed in a cylindrical shape. The cylindrical electrode 10 can be formed in a cylindrical shape as shown in FIGS. The cylindrical electrode 10 is installed on the facing surface 7a of the cathode electrode 7, and in this embodiment, the cathode electrode 7 is placed on the facing surface 7a. The cylindrical electrode 10 is configured such that one base end side opening of the pair of cylindrical openings is disposed so as to be opposed to the facing surface 7a of the cathode electrode 7 and is in contact with the facing surface 7a, and the other distal end side opening 10a. Is disposed on the opposite surface 7a of the cathode electrode 7 so as to be disposed at the tip of the anode electrode 6 side. That is, the cylindrical electrode 10 is installed so that the peripheral surface is erected from the opposing surface 7a toward the anode electrode 6 side on the upper side in the vertical direction, and has the opening 10a at the tip portion on the anode electrode 6 side. The cylindrical electrode 10 is in contact with the cathode electrode 7 so as to be conductive.

  Here, the base material 11 is placed so as to be accommodated inside the cylindrical electrode 10. That is, the cylindrical electrode 10 is placed on the facing surface 7 a of the cathode electrode 7 together with the base material 11 so as to surround the base material 11.

  In the present embodiment, a plurality of cylindrical electrodes 10 are provided on the facing surface 7 a of the cathode electrode 7 of the electrode portion 5. In each of the plurality of cylindrical electrodes 10, a base material 11 is provided inside thereof. Are individually housed. Each of the plurality of cylindrical electrodes 10 is preferably arranged on the opposing surface 7 a of the cathode electrode 7 at substantially equal intervals with the other adjacent cylindrical electrodes 10. In the example of FIGS. 2 and 3, five cylindrical electrodes 10 are installed on a single cathode electrode 7, and one cylindrical electrode 10 is disposed at the approximate center of the opposing surface 7a. The other four cylindrical electrodes 10 are arranged at substantially equal intervals in the radial direction of the facing surface 7a as the center. Further, these four cylindrical electrodes 10 are arranged at substantially equal intervals along the circumferential direction of the facing surface 7a. In each cylindrical electrode 10, as shown in FIG. 3, the base material 11 is disposed at the approximate center inside the cylindrical electrode 10, and one main surface is from the opening 10 a of the cylindrical electrode 10 to the anode electrode 6. Exposed to the side.

  In the state where the cylindrical electrode 10 is installed on the cathode electrode 7 as described above, the height dimension h (see FIG. 2) of the cylindrical electrode 10 is the distance between the anode electrode 6 and the cathode electrode 7. Is preferably 12.5% to 50% (h = 5 to 20 mm when the distance between the electrodes is 40 mm), more preferably 25% to 50% (h = 10 to 20 mm), 25 % (H = 10 mm) is even more preferable. As shown in FIG. 2, the height h of the cylindrical electrode 10 refers to the cylindrical electrode 10 in a state where the cylindrical electrode 10 is erected on the anode electrode 6 side from the facing surface 7 a of the cathode electrode 7. This is the distance between the proximal end and the distal end.

  Further, in the state where the cylindrical electrode 10 is installed on the cathode electrode 7 as described above, the sectional area A (see FIG. 3) of the cylindrical electrode 10 is 1 with respect to the area of the facing surface 7a of the cathode electrode 7. The area is preferably about% (when the diameter of the facing surface 7a is 300 mm, the diameter of the opening 10a of the cylindrical electrode 10 is 30 mm). The cross-sectional area A of the cylindrical electrode 10 is an area of a cross section perpendicular to the vertical direction of the cylindrical electrode 10, and is an area of the opening 10a of the cylindrical electrode 10 as shown in FIG.

  A method for forming a DLC film on the surface of the substrate 11 using the high-frequency plasma CVD apparatus 1 having the above configuration will be described. First, as shown in FIGS. 1 to 3, a plurality of cylindrical electrodes 10 are placed on the facing surface 7 a of the cathode electrode 7 among the electrode portions 5 installed in the reaction chamber 2. The base material 11 is mounted inside the mold electrode 10 one by one. The material of the substrate 11 is preferably a metal material such as stainless steel (SUS), but an insulating material such as glass can also be used.

  Next, preprocessing is performed. In the pretreatment, for example, air in the reaction chamber 2 is discharged from the discharge port 4 to reduce the pressure in the reaction chamber 2, and oxygen gas is introduced into the reaction chamber 2 from the introduction port 3. Thereafter, the high frequency output from the high frequency power source 9 is applied to the cathode electrode 7 via the matching unit 8. Thereby, oxygen plasma processing is performed in the storage chamber 2, and the surface of the base material 11 is activated.

Next, a film forming process is performed. In the film forming process, air in the reaction chamber 2 is discharged from the discharge port 4 to reduce the pressure in the reaction chamber 2, and hydrocarbon gas such as methane (CH ₄ ) is introduced into the reaction chamber 2 from the introduction port 3. be introduced. Thereafter, the high frequency output from the high frequency power source 9 is applied to the cathode electrode 7 via the matching unit 8. As a result, as shown in FIG. 1, the hydrocarbon-based gas is turned into plasma, and the molecules and atoms of the hydrocarbon-based gas are excited and become chemically active. The excited hydrocarbon gas molecules and atoms are accelerated in the direction of the cathode electrode 7 and collide with the opposing surface 7a, whereby a DLC film is formed. At this time, the plasma intensity is increased inside the cylindrical electrode 10 placed on the facing surface 7a of the cathode electrode 7 as compared with the outside, and the activity of the molecules and atoms of the hydrocarbon-based gas is increased. Has been promoted. Therefore, accelerated collision of hydrocarbon gas molecules and atoms is promoted inside the cylindrical electrode 10, and a denser DLC film is deposited on the surface of the substrate 11 placed inside at a high speed. Is done.

  Next, the effect of the high frequency plasma CVD apparatus 1 according to the present embodiment will be described.

  The high-frequency plasma CVD apparatus 1 of this embodiment has a reaction chamber 2 for introducing a raw material gas, and an anode electrode 6 and a cathode electrode 7 which are formed in a flat plate shape and are provided with opposing surfaces 6a and 7a facing each other. The electrode unit 5 disposed inside the chamber 2, the cylindrical electrode 10 that is installed on the opposing surface 7 a of the cathode electrode 7 together with the base material 11 and surrounds the periphery of the base material 11, and a high frequency is generated in the electrode unit 5. A high-frequency power source 9. The high-frequency plasma CVD apparatus 1 generates a high frequency between the anode electrode 6 and the cathode electrode 7 of the electrode unit 5 by a high-frequency power source 9 and converts the raw material gas introduced into the reaction chamber 2 into a plasma with a high frequency, The surface of the base material 11 that is installed in the reaction chamber 2 and surrounded by the cylindrical electrode 10 is processed using the plasma-generated source gas. More specifically, the high-frequency plasma CVD apparatus 1 is installed in the reaction chamber 2 by converting the raw material gas (hydrocarbon gas in the present embodiment) into plasma by high frequency and activating the chemical reaction of the raw material gas. A thin film (a DLC film in the present embodiment) is formed on the surface of the base material 11 surrounded by the cylindrical electrode 10.

  With this configuration, it is only necessary to newly install the cylindrical electrode 10 that surrounds the periphery of the base material 11 on the facing surface 7a of the cathode electrode 7 of the existing high-frequency plasma CVD apparatus 1, that is, inside the cylindrical electrode 10, that is, Since the plasma intensity around the substrate 11 can be increased, the formation of a DLC film utilizing a plasma reaction can be promoted. Moreover, since the adhesion of the formed DLC film can be improved without providing an intermediate layer in order to improve the adhesion between the DLC film and the base material as in the prior art, the film forming process can be simplified. In addition, the processing time can be reduced. Therefore, according to the high-frequency plasma CVD apparatus 1 of the present embodiment, processing of the substrate 11 using plasma can be promoted with a simple configuration.

  Moreover, in the high frequency plasma CVD apparatus 1 of this embodiment, the electrode part 5 has the anode electrode 6 disposed on the upper side in the vertical direction and the cathode electrode 7 disposed on the lower side in the vertical direction in the reaction chamber 2. . The cylindrical electrode 10 is placed on the facing surface 7 a of the cathode electrode 7.

  With this configuration, the cylindrical electrode 10 can be simply mounted on the facing surface 7a of the cathode electrode 7 provided on the upper side in the vertical direction, and the cylindrical electrode 10 is not particularly bonded or fastened. 10 can be positioned at a desired position on the opposing surface 7a, so that the DLC film formation utilizing the plasma reaction can be promoted with a simpler configuration.

  In the high-frequency plasma CVD apparatus 1 of the present embodiment, a plurality of cylindrical electrodes 10 are installed on the facing surface 7 a of the cathode electrode 7 of the electrode portion 5. With this configuration, since a plurality of base materials 11 can be simultaneously formed by a series of operations of the high-frequency plasma CVD apparatus 1, work efficiency of the DLC film forming operation can be improved. Further, since the number of the cylindrical electrodes 10 can be easily increased or decreased, productivity and versatility can be improved.

  In the high-frequency plasma CVD apparatus 1 of the present embodiment, the height h of the cylindrical electrode 10 is set between the anode electrode 6 and the cathode electrode 7 in a state where the cylindrical electrode 10 is installed on the cathode electrode 7. By adjusting the distance between the electrodes to 12.5% to 50%, the adhesion of the formed DLC film can be further improved. Similarly, when the cylindrical electrode 10 is installed on the cathode electrode 7, the cross-sectional area A of the cylindrical electrode 10 is set to 1% with respect to the area of the facing surface 7 a of the cathode electrode 7. The adhesion of the DLC film can be further improved.

  As mentioned above, although embodiment of this invention was described, the said embodiment was shown as an example and is not intending limiting the range of invention. The above embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. The above-described embodiments and modifications thereof are included in the invention described in the claims and equivalents thereof, as long as they are included in the scope and gist of the invention.

  In the above-described embodiment, the configuration in which the anode electrode 6 of the electrode unit 5 is arranged on the upper side in the vertical direction and the cathode electrode 7 is arranged on the lower side in the vertical direction is exemplified. However, the arrangement of the anode electrode 6 and the cathode electrode 7 is changed. Also good. When the cathode electrode 7 is arranged on the upper side in the vertical direction, the cylindrical electrode 10 is fixed and suspended on the facing surface 7a of the cathode electrode 7 facing the lower side in the vertical direction.

  In the said embodiment, although the cross-sectional shape of the cylindrical electrode 10 illustrated circular shape, shapes other than this may be sufficient. FIG. 4 is a plan view showing an example of a modification of the cylindrical electrode. As shown in FIG. 4, in the high-frequency plasma CVD apparatus 1 of the present embodiment, instead of the circular cylindrical electrode 10, for example, a rectangular cylindrical electrode 20, an elliptical cylindrical electrode 30, or A polygonal one like the hexagonal cylindrical electrode 40 can be applied. Moreover, the shape of the base material 11 may be other than a rectangular shape, or may be a three-dimensional shape.

  Moreover, in the said embodiment, although the high frequency plasma CVD apparatus 1 which applies high frequency plasma CVD method was illustrated, the apparatus which applies plasma CVD methods other than high frequency plasma CVD method may be used. For example, an apparatus using a plasma CVD method that generates a plasma state by supplying microwaves other than high frequency or direct current (DC) may be used.

  Moreover, although the apparatus which applies plasma CVD method was illustrated in the said embodiment, the plasma reaction apparatus using plasma reactions other than plasma CVD method may be sufficient. Examples of such a plasma reaction apparatus include a film formation apparatus using a sputtering method and an apparatus that performs reactive ion etching.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

  First, Example 1 and Example 1-2 regarding the point that the present invention can promote the processing of a base material utilizing a plasma reaction, specifically, the point that the formation of a DLC film on the surface of the base material can be promoted. Comparative example 1 will be described.

Example 1
A cylindrical cylindrical electrode made of stainless steel (SUS) is placed on a cathode electrode in a high-frequency plasma CVD apparatus (PED-401, Canon Anelva Corp.) having a parallel plate type electrode, and a substrate is formed in the cylindrical electrode. A DLC film was formed under the following conditions, and the film thickness with respect to the film formation time was measured.
・ Cross sectional diameter of cylindrical electrode: 30mm
-Cylindrical electrode height: 10mm
・ Si substrate dimensions: 20 mm x 20 mm x 1.0 mm
・ Cathode electrode diameter: 300mm
・ Distance between electrodes: 40mm
・ High frequency power: 200W
・ Gas pressure: 10Pa
・ Raw material gas: CH ₄ (methane gas)
・ Deposition time: 15 minutes

(Example 1-2)
In the same high-frequency plasma CVD apparatus as in Example 1, a cylindrical cylindrical electrode made of stainless steel (SUS) was placed on the cathode electrode, and a SUS substrate as a base material was placed in the cylindrical electrode. A DLC film was formed under the conditions described above. And the basic physical property of the sample surface after film-forming processing was performed by the surface chemical composition evaluation by X-ray photoelectron spectroscopy (XPS), and the structure evaluation of the film | membrane by Raman spectroscopy.
・ Cross sectional diameter of cylindrical electrode: 30mm
-Cylindrical electrode height: 10mm
・ SUS board dimensions: 20 mm x 20 mm x 2.0 mm
・ Cathode electrode diameter: 300mm
・ Distance between electrodes: 40mm
・ High frequency power: 200W
・ Gas pressure: 10Pa
・ Raw material gas: CH ₄ (methane gas)
-Film formation time: 15 minutes-Pretreatment conditions (high frequency power: 200 W, gas pressure: 10 Pa, source gas: O ₂ gas, treatment time: 10 minutes)

(Comparative Example 1)
In the same high-frequency plasma CVD apparatus as in Example 1 and Example 1-2, a cylindrical electrode was not installed, and a Si substrate (20 mm × 20 mm × 1.0 mm) as a base material was placed on the cathode electrode, A DLC film was formed under the same conditions as in Example 1, and the film thickness with respect to the film formation time was measured.

  FIG. 5 shows the deposition rate of the formed DLC film for Example 1 and Comparative Example 1 described above. In FIG. 5, the horizontal axis represents the film formation time (minutes), and the vertical axis represents the film thickness (nm) of the formed DLC film. Moreover, in FIG. 5, the film thickness for every film-forming time of Example 1 and the comparative example 1 is plotted by the rhombus and the round shape, respectively, and each transition is connected. As shown in FIG. 5, it was confirmed that the film formation rate of Example 1 was faster than that of Comparative Example 1, and the film formation of the DLC film on the surface of the substrate could be promoted.

  FIG. 6 is a diagram showing the chemical composition evaluation of the surface of the SUS substrate before and after the film formation process was performed in Example 1-2. In FIG. 6, the horizontal axis represents binding energy (eV), and the vertical axis represents intensity (au). In FIG. 6, the characteristics after the film forming process are shown by graphs A1, A2, and A3, and the characteristics before the film forming process are shown by graphs B1, B2, and B3. As shown in FIG. 6, the chemical composition of the surface of the SUS substrate before and after the film formation process was changed, and it was confirmed that the peak position was shifted particularly between the graphs A1 and B1. From the graphs A1, A2, and A3 showing the chemical composition of the surface of the SUS substrate after the film formation process, a DLC film is formed on the surface of the SUS substrate after the film formation process is performed in Example 1. Was confirmed.

FIG. 7 is a diagram showing the structural evaluation of the thin film formed in Example 1-2. In FIG. 7, the horizontal axis represents Raman shift (cm ⁻¹ ), and the vertical axis represents Raman intensity. As shown in FIG. 7, in the structure evaluation of the film by Raman spectroscopy, a G-band peak can be confirmed near 1540 cm ⁻¹ in the prepared sample, and a D-band peak can be confirmed near 1340 cm ^−1. Therefore, it was confirmed that a typical DLC film was formed on the surface of the SUS substrate after the film formation process in Example 1 was performed.

  Further, when the emission intensity of the plasma generated on the opposite surface of the cathode electrode during the film forming process of Example 1 was observed, the emission intensity of the plasma at the upper end of the cylindrical electrode, that is, in the vicinity of the base material, was 8. 7 μW. On the other hand, when the same observation was made in Comparative Example 1, the emission intensity of the plasma generated on the opposite surface of the cathode electrode when the cylindrical electrode was not installed was 7.4 μW. Therefore, when the cylindrical electrode is installed (Example 1), the plasma emission intensity in the region near the substrate is about 1.2 times as compared with the case where the cylindrical electrode is not installed (Comparative Example 1). It has been confirmed that it has increased.

  Therefore, as shown in FIGS. 5-7, according to this invention, it was confirmed that the film-forming of the DLC film on the surface of the base material using a plasma reaction can be accelerated | stimulated.

  Next, the point which can improve the adhesiveness of the DLC film formed by this invention is demonstrated, giving Examples 2-4 and the comparative example 2. FIG.

(Example 2)
In the same high-frequency plasma CVD apparatus as in Example 1 and Example 1-2, a DLC film was formed under the same conditions as in Example 1-2, and the critical load value of the DLC film was measured three times by a scratch test. The adhesion between the SUS substrate and the DLC film was evaluated based on the average value. The basic physical properties of the sample surface were evaluated by the structure evaluation of the film by Raman spectroscopy.

(Example 3)
A DLC film was formed under the same conditions as in Example 2 except that the height of the cylindrical electrode was 20 mm, and adhesion evaluation by a scratch test and film structure evaluation by Raman spectroscopy were performed.

Example 4
A DLC film was formed under the same conditions as in Example 2 except that the height of the cylindrical electrode was 5 mm, and adhesion evaluation by a scratch test and film structure evaluation by Raman spectroscopy were performed.

(Comparative Example 2)
A DLC film was formed under the same conditions as in Example 2 except that a cylindrical electrode was not installed and a SUS substrate as a base material was disposed on the cathode electrode, and adhesion evaluation and Raman spectroscopy by a scratch test were performed. The structure of the film was evaluated.

  FIG. 8 is a diagram showing the results of evaluating the adhesion of the DLC film in Examples 2 to 4 and Comparative Example 2. In FIG. 8, the horizontal axis represents the height dimension (mm) of the cylindrical electrode, and the leftmost side shows Comparative Example 2 in which the cylindrical electrode is not installed. The vertical axis | shaft of FIG. 8 represents the average value (N) of the measured critical load. In FIG. 8, the critical load values of Examples 2 to 4 and Comparative Example 2 are displayed as bar graphs. As shown in FIG. 8, in the samples of Examples 2 to 4 in which the film was formed using the cylindrical electrode, the critical load value was increased as compared with Comparative Example 2 in which the cylindrical electrode was not installed. It was confirmed that the adhesion was improved. In particular, in Example 2 where the height dimension of the cylindrical electrode is 10 mm, the average critical load value increases to 8.5 N, and a value nearly twice as large as that in Comparative Example 2 in which the cylindrical electrode is not used is obtained. It was.

FIG. 9 is a diagram showing film structure evaluation by Raman spectroscopy in Examples 2 to 4 and Comparative Example 2. The horizontal and vertical axes in FIG. 9 are the same as those in FIG. In FIG. 9, the results of structural evaluation by Raman spectroscopy of Examples 2 to 4 and Comparative Example 2 are individually shown. As shown in FIG. 9, it was confirmed that the peak of the G band was shifted from about 1564 cm ⁻¹ to about 1523 cm ⁻¹ toward the low wavenumber side as the height of the cylindrical electrode increased. From this result, since the sp ³ / sp ² ratio in the film was increased, it was confirmed that the ratio of the diamond structure in the DLC film was increased. Such a change in the film structure is considered to have improved the adhesion.

  Therefore, as shown in FIGS. 8 and 9, it was confirmed that the adhesion of the DLC film formed on the substrate can be improved according to the present invention.

  Next, with respect to the point that the adhesion of the DLC film formed on the surface can be improved not only in the case where the substrate is a metal material but also in the case of an insulating material according to the present invention, Examples 5 and 6, Comparative Example 3 4 will be described.

(Example 5)
In the same high-frequency plasma CVD apparatus as in Example 1 and Example 1-2, a DLC film was formed under the same conditions as in Example 1-2, and the adhesion between the SUS substrate and the DLC film was evaluated by a tape test. did.

(Example 6)
A DLC film was formed under the same conditions as in Example 5 except that the substrate was a glass substrate (20 mm × 20 mm × 1.0 mm), and the adhesion of the DLC film was evaluated by a tape test.

(Comparative Example 3)
In the same high-frequency plasma CVD apparatus as in Comparative Example 2, a DLC film was formed under the same conditions as in Comparative Example 2, and the adhesion of the DLC film was evaluated by a tape test.

(Comparative Example 4)
A DLC film was formed under the same conditions as in Comparative Example 3 except that the substrate was a glass substrate (20 mm × 20 mm × 1.0 mm), and the adhesion of the DLC film was evaluated by a tape test.

The results of evaluating the adhesion of the DLC film in Examples 5 and 6 and Comparative Examples 3 and 4 are shown in Table 1 below. In Table 1, the results of the adhesion evaluation are represented in four stages of a double circle (）), a circle (◯), a triangle (Δ), and a cross (×) in order from the better. . Here, double circles indicate that good adhesion was confirmed without peeling on the entire surface, circles indicate that good adhesion was partially confirmed, triangles indicate the entire surface The case where peeling was confirmed and the cross mark was that film formation was impossible were used as evaluation criteria for each stage of adhesion evaluation.

  As shown in Table 1, the evaluation results of Examples 5 and 6 are better than those of Comparative Example 3 of the reference, and the substrate material is not only a metal material but also an insulating material such as glass. It was confirmed that the adhesion of the DLC film formed on the surface of the substrate can be improved by the method of the present invention.

  Next, in addition to Example 5 above, Examples 7 to 9 and Comparative Example 5 are given as regards that the adhesion of the DLC film can be further improved by adjusting the height dimension h (see FIG. 2) of the cylindrical electrode. I will explain.

(Example 7)
A DLC film was formed under the same conditions as in Example 5 except that the height of the cylindrical electrode was 5 mm, and the adhesion of the DLC film was evaluated by a tape test.

(Example 8)
A DLC film was formed under the same conditions as in Example 5 except that the height of the cylindrical electrode was 20 mm, and the adhesion of the DLC film was evaluated by a tape test.

Example 9
A DLC film was formed under the same conditions as in Example 5 except that the height of the cylindrical electrode was 30 mm, and the adhesion of the DLC film was evaluated by a tape test.

(Comparative Example 5)
A DLC film was formed under the same conditions as in Example 5 except that the height of the cylindrical electrode was 35 mm, and the adhesion of the DLC film was evaluated by a tape test.

The results of the adhesion evaluation of the DLC films in Examples 5 and 7 to 9 and Comparative Example 5 are shown in Table 2 below. In Table 2, the evaluation results are shown in four stages with the same marks as in Table 1. Table 2 also shows the height dimension of the cylindrical electrode of each example as a ratio to the interelectrode distance (40 mm) between the anode electrode and the cathode electrode of the high-frequency plasma CVD apparatus.

  As shown in Table 2, the height of the cylindrical electrode is 12.5% to 50% with respect to the interelectrode distance between the anode electrode and the cathode electrode (h = 5 when the interelectrode distance is 40 mm). 20 mm), preferably 25% to 50% (h = 10 to 20 mm). Further, considering the result of the adhesion evaluation of the DLC film shown in FIG. 8 as well, the height of the cylindrical electrode is 25% (h) relative to the interelectrode distance between the anode electrode and the cathode electrode. = 10 mm) was confirmed to be even more preferable.

  Therefore, as shown in Table 2 and FIG. 8, it was confirmed in the present invention that the adhesion of the DLC film can be further improved by adjusting the height dimension of the cylindrical electrode.

  Next, the point that the adhesion of the DLC film can be further improved by adjusting the cross-sectional area A (see FIG. 3) of the cylindrical electrode will be described with reference to Examples 10 to 12 in addition to Example 5 described above.

(Example 10)
A DLC film was formed under the same conditions as in Example 5 except that the diameter of the cross section of the cylindrical electrode was 15 mm, and the adhesion of the DLC film was evaluated by a tape test.

(Example 11)
A DLC film was formed under the same conditions as in Example 5 except that the diameter of the cross section of the cylindrical electrode was 50 mm, and the adhesion of the DLC film was evaluated by a tape test.

(Example 12)
A DLC film was formed under the same conditions as in Example 5 except that the diameter of the cross section of the cylindrical electrode was 75 mm, and the adhesion of the DLC film was evaluated by a tape test.

The results of evaluation of the adhesion of the DLC film in Examples 5 and 10 to 12 are shown in Table 3 below. In Table 3, the evaluation results are shown in four stages with the same marks as in Table 1. Table 3 also shows the cross-sectional area of the cylindrical electrode of each example as a ratio with respect to the area (a circle having a diameter of 300 mm) of the surface facing the cathode electrode of the high-frequency plasma CVD apparatus.

  As shown in Table 3, the cross-sectional area of the cylindrical electrode is an area of 1% with respect to the area of the opposing surface of the cathode electrode (when the diameter of the opposing surface is 300 mm, the diameter of the opening of the cylindrical electrode is 30 mm). It was confirmed that it was preferable. Therefore, as shown in Table 3, it was confirmed that the adhesion of the DLC film can be further improved by adjusting the cross-sectional area of the cylindrical electrode in the present invention.

1 High-frequency plasma CVD equipment (plasma reaction equipment)
2 Reaction chamber 5 Electrode section 6 Anode electrode 7 Cathode electrode 9 High frequency power supply (power supply)
10 Cylindrical electrode 11 Base material

Claims (7)

A reaction chamber for introducing a reaction gas;
An electrode part having an anode electrode and a cathode electrode formed in a flat plate shape and provided with opposing surfaces facing each other, and disposed inside the reaction chamber;
A cylindrical electrode that is installed together with a base material on the opposite surface of the cathode electrode and surrounds the periphery of the base material;
A power source for generating electromagnetic waves in the electrode part;
With
The electromagnetic wave is generated between the anode electrode and the cathode electrode of the electrode part by the power source, and the reaction gas introduced into the reaction chamber is converted into plasma by the electromagnetic wave, thereby generating the plasma reaction. Processing the surface of the base material that is installed in the reaction chamber and surrounded by the cylindrical electrode using gas,
A plasma reactor characterized by that. The reaction gas introduced into the reaction chamber is a raw material gas,
By forming the raw material gas into plasma by the electromagnetic wave and activating the chemical reaction of the raw material gas, a thin film is formed on the surface of the base material installed in the reaction chamber and surrounded by the cylindrical electrode.
The plasma reactor according to claim 1. The thin film is a diamond-like carbon (DLC) film,
The plasma reactor according to claim 2. In the reaction chamber, the anode electrode is disposed on the upper side in the vertical direction, and the cathode electrode is disposed on the lower side in the vertical direction in the reaction chamber,
The cylindrical electrode is placed on the facing surface of the cathode electrode.
The plasma reactor according to any one of claims 1 to 3. A plurality of the cylindrical electrodes are installed on the facing surface of the cathode electrode of the electrode portion,
The plasma reaction apparatus of any one of Claims 1-4. In the state where the cylindrical electrode is installed on the cathode electrode, the height dimension of the cylindrical electrode is 12.5% to 50% with respect to the inter-electrode distance between the anode electrode and the cathode electrode. Is,
The plasma reactor according to any one of claims 1 to 5. In a state where the cylindrical electrode is installed on the cathode electrode, a cross-sectional area of the cylindrical electrode is 1% with respect to an area of the facing surface of the cathode electrode.
The plasma reactor according to any one of claims 1 to 6.

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