JP5299674B2 - Method for forming amorphous hard carbon film and apparatus for forming the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film deposition method of an amorphous hard carbon film capable of obtaining the amorphous hard carbon film having higher hardness compared with the former, with hydrocarbon-based gas under the atmospheric pressure being raw material thereof, and to provide a film deposition apparatus therefor. <P>SOLUTION: The film deposition method of the amorphous hard carbon film includes a base material holding step of holding a base material to a holding electrode, and a film deposition step of depositing the amorphous hard carbon film on a surface of the base material by applying the AC voltage to an application electrode, generating the glow discharge plasma between an electrode body and surface of the base material, and exhausting exhaust gas while the electrode body having the application electrode is opposite to the holding electrode, raw material gas containing hydrocarbon based gas is fed between the electrode body and the holding electrode, and the DC bias voltage is generated between the electrode body and the holding electrode. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a method for forming an amorphous hard carbon film under an atmospheric pressure atmosphere and a film forming apparatus therefor.

  Amorphous hard carbon films have characteristics of high hardness, low wear, low friction, and excellent surface smoothness, and are used by being coated on dies, tools, sliding parts, and the like. An amorphous hard carbon film is an amorphous hard carbon film containing a relatively large number of carbon atoms in the same bonding state as diamond, and is generally called a diamond-like carbon (DLC) film. It is known that the properties of the DLC film differ depending on the raw materials used and the film forming method. As a method for forming a DLC film, plasma CVD or sputtering is generally used. However, in the film formation method using the plasma CVD method or the sputtering method, a uniform plasma cannot be obtained over a wide range, and a region where a homogeneous film can be formed is limited and it is difficult to increase the area. In addition, the film forming speed is low because it is performed in a low pressure environment, and there is a problem that productivity is difficult because it is a batch type using a vacuum vessel.

  Although it is not disclosed as a film formation method for a DLC film, a film formation method using a discharge plasma treatment in the vicinity of atmospheric pressure is a method for improving the above disadvantages of other film formation methods using a plasma CVD method or a sputtering method. Proposed. However, the diffusion of the mixed gas introduced into the discharge space in the vicinity of the atmospheric pressure tends to cause a bias of the mixed gas as compared with the diffusion of the mixed gas in a low pressure environment, and the formed film tends to be non-uniform.

  In the DLC film formation method, hydrogen (H) is basically left during film formation when a hydrocarbon gas is used as a source gas. Therefore, a DLC film formed using a hydrocarbon gas as a raw material gas has low film quality hardness.

  Although it is not the film formation method of DLC film in patent document 1, the plasma processing space is formed under atmospheric pressure between a pair of upper and lower electrodes with the base material transport roll as a counter electrode, and the polymer placed on the base material transport roll There has been disclosed a plasma processing apparatus for performing plasma processing for continuously applying a uniform thin film to an object to be processed such as a film.

Patent Document 2 discloses a method capable of forming a uniform atmospheric pressure plasma discharge as in Patent Document 1.
JP 2006-97105 A JP 2006-249470 A

  However, in these plasma processing methods under atmospheric pressure, there is no disclosure of a method for forming an amorphous hard carbon film using a hydrocarbon gas as a raw material, and an amorphous hard carbon material using a hydrocarbon gas as a raw material. None have solved the problem that the film hardness of the carbon film forming method is low.

  The present invention has been made in view of such circumstances, and is carried out in an atmospheric pressure atmosphere using a hydrocarbon-based gas as a raw material gas, whereby an amorphous hard carbon film having a higher hardness than before can be obtained. An object of the present invention is to provide a carbon film forming method and a film forming apparatus therefor.

  Therefore, the present inventors have intensively studied to solve this problem, and as a result of repeated trial and error, by forming a film by applying a DC bias voltage to the holding electrode holding the base material, in an atmospheric pressure atmosphere, It has been found that an amorphous hard carbon film having a hardness equivalent to that of a silica film can be formed using a hydrocarbon gas as a raw material gas, and the present invention has been completed.

(Film formation method of amorphous hard carbon film)
That is, the method for forming an amorphous hard carbon film of the present invention includes a substrate holding step of holding a substrate on a holding electrode, and an electrode body having an application electrode facing the holding electrode in an atmospheric pressure atmosphere, A source gas containing a hydrocarbon-based gas is supplied between the electrode body and the holding electrode, and an AC voltage is applied to the applied electrode while generating a DC bias voltage between the electrode body and the holding electrode, and the electrode body and the base electrode A film forming step of generating glow discharge plasma with the surface of the material, discharging exhaust gas, and forming an amorphous hard carbon film on the surface of the substrate.

  In the film forming step, a DC bias voltage is applied between the electrode body and the holding electrode by applying a DC bias voltage to the holding electrode, and the substrate held by the holding electrode has polarity. Therefore, the ion species ionized by the plasma are attracted by the polarity of the substrate, and the collision energy of the ion species against the substrate increases. This is considered to activate the reaction on the substrate surface.

  Further, it is considered that the increase in the collision energy reduces the proportion of hydrogen remaining in the amorphous hard carbon film and increases the hardness of the film quality. Therefore, by using this method, it is possible to form an amorphous hard carbon film having a higher hardness than before.

  The DC bias voltage is preferably DC 200V to 10,000V. Furthermore, the AC voltage is preferably a frequency of 0.1 kHz or more and a voltage of 5 kV to 50 kV.

  If the DC bias voltage is less than DC 200V, the effect of bias is difficult to obtain, and if the voltage is greater than DC 10000V, dielectric breakdown tends to occur.

  Appropriate glow discharge plasma can be generated by applying an alternating voltage of a frequency of 0.1 kHz or more and 5 kV to 50 kV to the application electrode. When the AC voltage is less than 5 kV, ionization of the raw material gas is difficult to proceed, and when the AC voltage is greater than 50 kV, arc discharge is likely to occur.

  The frequency may be 0.1 kHz or more and is not particularly limited.

  The mixing ratio of the raw material gas is preferably inert gas / hydrocarbon gas = 0/100 to 99.9 / 0.1. As a result, plasma can be stabilized and high-speed processing can be performed. Since the hydrocarbon-based gas is less likely to be ionized than the inert gas, the ionization proceeds more easily when the hydrocarbon-based gas ratio is smaller than the inert gas.

  The discharge gap distance between the electrode body and the holding electrode is preferably 0.1 mm to 5 mm. By setting the discharge gap distance between the electrode body and the holding electrode to be 0.1 mm to 5 mm, a stable gas flow can be created and generation of unnecessary discharge can be suppressed. If the discharge gap distance is smaller than 0.1 mm, partial abnormal discharge is likely to occur. If the discharge gap distance is larger than 5 mm, high input power is required to ionize the source gas.

  By combining these steps, it is possible to form an amorphous hard carbon film that is more uniform and harder than the conventional one using a hydrocarbon-based gas as a source gas under an atmospheric pressure atmosphere. I can do it.

  The holding electrode may be provided with a heating means for heating the substrate, and the film forming step may be performed while heating the substrate to 50 ° C to 300 ° C. The reaction on the surface of the substrate is activated by heating the substrate. At this time, even if the substrate is heated at a temperature lower than 50 ° C., the reaction on the surface of the substrate is hardly activated, and if the temperature is higher than 300 ° C., the formed film is easily decomposed and the film Hardness decreases.

  In the film formation step, it is preferable to supply the source gas and exhaust the exhaust gas so that the gas flow rate is 200 mm / sec to 3,000 mm / sec. If the gas flow rate is slower than 200 mm / sec, it is difficult to produce a uniform gas flow, and local discharge is likely to occur. Further, foreign matters such as droplets are easily generated, and the film quality is deteriorated. On the other hand, if the gas flow rate is faster than 3,000 mm / sec, the raw material gas component is exhausted before being deposited, and the film formation rate is reduced.

  In the substrate holding step, it is preferable to hold the surface of the substrate and the electrode surface of the holding electrode in substantially the same plane. “Substantially the same plane” means that the base material is held in a shape along the plane or curved surface of the electrode surface of the holding electrode. In this case, the base material at the time of film formation and the application electrode surface opposite to each other have a shape along which the discharge gap distance is provided. If the surface of the substrate is flat, the electrode surface of the application electrode also has a planar shape, and if the surface of the substrate is a curved surface, the electrode surface of the application electrode also has a curved surface along the substrate.

  By holding the base material so that the surface of the base material and the electrode surface of the holding electrode are substantially in the same plane, a stable gas flow can be created in the discharge space, and generation of unnecessary discharge can be suppressed.

  In addition, the surface of the application electrode is preferably covered with a dielectric. Since the surface of the application electrode is covered with a dielectric, the transition to arc discharge can be suppressed.

  In the film forming step, the holding electrode and the electrode body may be moved relative to each other. This relative movement may be a parallel movement in one direction or a rotational movement. By relatively moving the holding electrode and the electrode body so as to match the shape of the substrate, a uniform film can be formed efficiently. Further, by relatively moving the holding electrode and the electrode body, a plurality of base materials can be continuously subjected to plasma treatment.

(Amorphous hard carbon film deposition system)
The amorphous hard carbon film-forming apparatus of the present invention includes a holding electrode for holding a substrate, an electrode body that is positioned opposite to the holding electrode and has an application electrode, and a gap between the holding electrode and the electrode body. A voltage applying means for applying a high frequency electric field to an applying electrode for generating glow discharge plasma in an atmospheric pressure atmosphere; a DC bias voltage applying means for generating a DC bias voltage between the electrode body and the holding electrode; and a holding electrode A raw material gas supply means for supplying a raw material gas for forming an amorphous hard carbon film on the surface of the substrate, and an exhaust means for discharging exhaust gas between the holding electrode and the electrode body, It is characterized by having.

  The holding electrode may be provided with a heating means for heating the substrate on the back surface.

  Furthermore, the source gas supply means rectifies the source gas and has a gas supply nozzle for supplying the source gas so that the source gas is in a laminar flow state at least in the base material atmosphere, and the exhaust means rectifies the source gas. In addition, an exhaust nozzle for exhausting the source gas may be provided so that the source gas is in a laminar flow state at least in the base material atmosphere. By making the source gas into a laminar flow state by the gas supply nozzle and the exhaust nozzle, a uniform gas flow can be created in the base material atmosphere.

  Furthermore, it has a moving means for relatively moving the holding electrode and the electrode body, and the electrode body has a plurality of application electrodes, and supplies a source gas between one application electrode and the other application electrode. A gas supply port may be provided, and exhaust ports may be provided on at least both sides of the gas supply port applied electrode.

  Since the holding electrode holding the substrate and the electrode body can move relative to each other, a plurality of substrates can be subjected to plasma treatment continuously. In addition, since the exhaust ports are disposed at least on both sides of the application electrode of the gas supply port, a uniform line-shaped gas flow can be formed in a narrower range. Further, convection of a difficult source gas is likely to occur under an atmospheric pressure atmosphere, the source gas is evenly diffused, and an amorphous hard carbon film can be uniformly formed on the surface of the substrate.

  In addition, the surface of the application electrode is preferably covered with a dielectric.

  By using a film forming apparatus for an amorphous hard carbon film having the above structure, an amorphous hard carbon film having a uniform and higher hardness than the conventional one can be formed on a substrate using a hydrocarbon-based source gas under an atmospheric pressure atmosphere. A film can be formed.

  By using the method and apparatus for forming an amorphous hard carbon film according to the present invention, a hydrocarbon gas is used as a raw material in an atmospheric pressure atmosphere and has a hardness equivalent to that of a silica film having a higher hardness than before. A crystalline hard carbon film can be formed.

(Film formation method of amorphous hard carbon film)
The method for forming an amorphous hard carbon film of the present invention includes a substrate holding step and a film forming step.

  Of these, the substrate holding step is a step of holding the substrate on the holding electrode.

  The substrate is not particularly limited. For example, examples of the substrate include a metal substrate, a polymer substrate, a glass substrate, and a ceramic substrate.

  The holding electrode is an electrode having a shape that can hold the substrate. The material of the holding electrode is not particularly limited as long as it is made of a conductor. Examples of the material include metal materials such as aluminum, copper, and brass, and carbon materials. The holding electrode may be held by forming a recess, holding the substrate, holding the substrate between a plurality of divided holding electrodes, or forming a through hole in the holding electrode. A material may be sandwiched. Also, a plurality of recesses may be formed to hold a plurality of base materials, or the base materials may be held with both surfaces open from both sides.

  The shape of the holding electrode may be a curved surface shape such that when the surface of the base material has a curved surface shape, the holding electrode has substantially the same surface shape. Among these, a shape having a parallel flat portion between the application electrode and the holding electrode is more preferable, and it is preferable that both electrodes have a substantially planar shape.

  Further, the holding electrode may be provided with a heating means for heating the base material on the back surface thereof. The heating means is not particularly limited, and a commercially available electric heater or infrared heater can be used. The temperature of the substrate need not be particularly controlled, but it is preferable that the temperature of the substrate is 50 ° C to 300 ° C. Moreover, it is more preferable that the temperature of the base material is 150 ° C to 250 ° C.

  The film forming process is performed in an atmospheric pressure atmosphere. Further, an electrode body having an application electrode is made to face the holding electrode, a raw material gas containing a hydrocarbon gas is supplied between the electrode body and the holding electrode, and a DC bias voltage is applied to the holding electrode, whereby the electrode body While generating a DC bias voltage between the electrode and the holding electrode, an AC voltage is applied to the applied electrode to generate glow discharge plasma between the electrode body and the surface of the substrate, exhaust gas is exhausted, An amorphous hard carbon film is formed on the surface.

  “Atmospheric pressure atmosphere” refers to a pressure when film formation is performed in an atmospheric pressure open environment, and includes a range of pressure fluctuation due to gas supply and exhaust. Specifically, it indicates a pressure of 0.5 atm (about 50 kPa) or more and 2 atm (about 203 kPa) or less.

  The application electrode is not particularly limited as long as it is formed of a conductor. For example, metal materials such as aluminum, copper, and brass can be used as the material.

  The application electrode is covered with a dielectric. As a result, it is possible to suppress the occurrence of arc discharge due to dielectric breakdown during voltage application. At this time, the dielectric may be disposed in contact with the application electrode, or an electrode sprayed with a dielectric may be used for the application electrode.

  The dielectric material may be any material having a dielectric constant of 3 or more. Examples of the dielectric material include glass, metal oxides such as silicon dioxide, aluminum oxide, zirconium dioxide, and titanium dioxide, and double oxides such as barium titanate. Energy can be efficiently injected between the electrodes by using aluminum oxide or zirconium dioxide having a high dielectric constant as the dielectric.

  The shape of the application electrode is not particularly limited as long as it has a length corresponding to the film formation method. A power source is connected to the application electrode and applied. The power source may be an AC power source having a frequency of 0.1 kHz or more generally used in atmospheric pressure plasma discharge, and an AC pulse power source or an RF power source can be used as the power source. The voltage of the power source is preferably 5 kV to 50 kV, and more preferably 10 kV to 30 kV.

  The electrode body having the application electrode and the holding electrode are opposed to each other with a discharge gap distance therebetween. The discharge gap distance is preferably 0.1 mm to 5 mm, and more preferably 0.3 to 2 mm. When the film forming process is performed within this range, it is easy to obtain a stable gas flow and a uniform discharge in the gap space.

  The source gas may contain a hydrocarbon gas. As the raw material gas, a mixed gas of an inert gas as an atmospheric gas and a hydrocarbon-based gas as a reaction gas is used at a mixing ratio of 0/100 to 99.9 / 0.1. That is, it may be a hydrocarbon-based gas alone or a mixed gas of a hydrocarbon-based gas and an inert gas. More preferably, the mixing ratio of the mixed gas is used in the range of inert gas / hydrocarbon-based gas = 80/20 to 99/1. When used in this range, good film characteristics such as a stable discharge by atmospheric gas and a smooth surface by dense decomposition of the reaction gas and dense film formation can be obtained.

  In addition to the hydrocarbon-based gas, other component gases may be added as the reaction gas. For the purpose of enhancing the function of the film, a gas containing a metal or Si component can be added simultaneously.

  The mixing ratio of the source gases may be a constant ratio during the amorphous hard carbon film forming process, or may be changed during the film forming process. When the mixing ratio is changed, functional films having different film properties in the film thickness direction can be formed.

  As the inert gas, helium, argon, or nitrogen can be used alone or as a mixture of two or more thereof. Nitrogen gas is preferable because of lower cost. In addition, helium may be used for film formation with low energy and high hardness.

  The hydrocarbon-based gas can include saturated hydrocarbons such as methane, ethane, and propane, and unsaturated hydrocarbons such as ethylene, acetylene, and benzene. Among them, it is preferable to use acetylene having high reactivity.

  Such a raw material gas is supplied at a raw material gas flow rate of 200 mm / sec to 3000 mm / sec. More preferably, the raw material gas is supplied at a flow rate of 200 mm / sec to 2000 mm / sec. Further, it is preferable that the exhaust is performed under conditions equal to or higher than the raw material gas flow rate. By exhausting at a speed equal to or higher than the raw material gas flow rate, the raw material gas is uniformly convected and the raw material gas is evenly diffused. Such supply of the source gas can be controlled by a control valve of a cylinder that supplies the source gas. The exhaust can be controlled by a control valve such as an exhaust pump.

  A DC bias voltage is applied to the holding electrode. At this time, even if it is not directly applied to the holding electrode, it is only necessary that the holding electrode is applied as a result. That is, a state where a DC bias voltage is applied to the application electrode and the holding electrode is grounded may be used.

  The DC bias voltage at this time is preferably DC 200V to 10000V, and more preferably 1000V to 7000V.

  Under such conditions, an AC voltage is applied to the applied electrode to generate glow discharge plasma between the electrode body and the surface of the substrate, thereby forming an amorphous hard carbon film on the surface of the substrate. The At that time, the electrode body and the holding electrode may move relative to each other. The moving speed is determined by the film forming speed. That is, the electrode body and the holding electrode may be moved relative to each other at a speed at which a film having a required thickness can be formed.

(Amorphous hard carbon film deposition system)
The amorphous hard carbon film forming apparatus of the present invention includes a holding electrode, an electrode body, a voltage applying unit, a DC bias voltage applying unit, a source gas supply unit, and an exhaust unit.

  The holding electrode and the electrode body are the same as those described in the film forming method.

  The voltage application means includes a power supply applied to the application electrode and a capacitor corresponding to the power supply.

  The power source connected to the application electrode is the same as that described in the film formation method. The first capacitor is disposed in order to prevent a direct current component of a direct current power source, which will be described later, from flowing into the alternating current power source side. The first capacitor is not particularly limited as long as it can withstand the voltage of the AC power supply used. A commercially available capacitor can be used as the first capacitor.

  The DC bias voltage applying means includes a DC power source for applying a DC bias voltage to the holding electrode, a second capacitor, and a coil.

  The DC power source is the same as that described in the film formation method. The second capacitor and the coil are disposed in order to prevent the high frequency component of the AC power source from flowing into the DC power source side. The second capacitor is not particularly limited as long as it can withstand the voltage of the DC power supply used. A commercially available capacitor can be used as the second capacitor.

  The coil should just be the specification corresponding to the frequency of AC power supply.

  The source gas supply means has a gas supply nozzle or a gas supply port for supplying source gas between the electrode body and the holding electrode. The exhaust means has an exhaust nozzle or an exhaust port.

  The gas supply nozzle is not particularly limited as long as it can flow the raw material gas rectified so that the raw material gas is in a laminar flow state in a substrate atmosphere. Therefore, the gas supply nozzle preferably has a width wider than the width of the substrate on which the amorphous hard carbon film is formed.

  Similarly, the exhaust nozzle preferably has a width wider than the width of the substrate on which the amorphous hard carbon film is formed.

  The gas supply port is arranged to supply a source gas between one application electrode and the other application electrode, and gas exhaust ports are arranged at least on both sides of the application electrode of the gas supply port. It is preferable to install. The gas supply port and the exhaust port may have a slit shape. The width of the slit is preferably about 1 to 2 times the discharge gap distance. The slit length may be long enough to cover the surface on which the amorphous hard carbon film is formed.

  The gas supply nozzle and the gas supply port are connected to a cylinder for supplying the raw material gas, and the flow rate is controlled by a control valve. The exhaust nozzle and the exhaust port are connected to an exhaust pump or the like, and are sucked by the exhaust pump to exhaust the source gas.

  The amorphous hard carbon film forming apparatus of the present invention may further have a moving means.

  The moving means moves the holding electrode and the electrode body relative to each other. The moving means is not particularly limited as long as it can perform the relative movement described in the film forming method. For example, the holding electrode or the electrode body may have a moving means, and the holding electrode or the gas supply electrode body may be installed in the moving means. The moving direction can be selected as appropriate, such as parallel movement or rotational movement.

  Next, a preferred embodiment will be described, and the present invention will be described in more detail with reference to FIGS. Each example describes a method for forming an amorphous hard carbon film, but at the same time serves as an explanation for a film forming apparatus for an amorphous hard carbon film.

[First embodiment]
FIG. 1 is a schematic explanatory view showing a first embodiment of a film forming apparatus for an amorphous hard carbon film of the present invention.

  In the film forming apparatus 100 shown in FIG. 1, a method for forming an amorphous hard carbon film on the surface of the substrate 4 is described. The holding electrode 6 has a flat plate shape and is formed with a concave portion that is large enough to accommodate one plate-like base material 4. The base material 4 has a concave portion that is substantially the same height as the surface height of the holding electrode 6. Is housed in.

  A plate-shaped heating device 5 for heating the base material 4 is disposed on the back surface of the holding electrode 6 in which the base material 4 is accommodated. The heating device 5 includes a plate heater and a thermocouple.

  The plate-like application electrode 2 is coated with a dielectric 3 on the surface facing the substrate 4. The holding electrode 6 and the application electrode 2 are arranged in parallel via a set discharge gap distance.

  The holding electrode 6 and the application electrode 2 are wired, and an AC voltage is applied by the voltage application means 20. A positive DC bias voltage is applied to the application electrode 2 by the DC bias voltage application means 30. In this case, the holding electrode 6 is grounded. As a result, the positive ions are relatively attracted to the holding electrode 6 side. In FIG. 1, a circuit configuration in which a positive DC bias voltage is applied to the application electrode 2 is adopted, but a circuit configuration in which a negative DC bias voltage is directly applied to the holding electrode 6 may be employed.

  The voltage applying means 20 includes a high voltage pulse power supply 1 and a first capacitor 10. The DC bias voltage applying means 30 includes a DC power source 7, a second capacitor 9, and a filter coil 8.

  The source gas is supplied in the direction of arrow A between the holding electrode 6 and the application electrode 2, and the gas is exhausted in the direction of arrow B. As a result, a new source gas always flows between the application electrode 2 and the holding electrode 6 in a certain direction. Although not shown, in order to supply the source gas in the direction of arrow A, the outlet of the source gas is connected to a cylinder for supplying the source gas, and the flow rate is controlled by a control valve. In order to exhaust in the direction of arrow B, the exhaust port of the source gas is connected to an exhaust pump or the like, and is sucked by the exhaust pump to exhaust the source gas.

  Next, a film forming method will be described. The gap distance between the holding electrode 6 and the application electrode 2 is set to 0.1 mm to 5 mm, and the raw material gas is mixed there between: inert gas / hydrocarbon gas mixture ratio = 0/100 to 99.9 / 0.1, Source gas flow rate: 200 mm / sec to 3000 mm / sec. At the same time, exhaust is performed at a speed equal to or higher than that of the raw material gas. By doing so, the source gas is uniformly convected and the source gas is evenly diffused.

  The holding electrode 6 that holds the substrate 4 is preheated to 50 ° C. to 300 ° C. by the heating device 5. When the base material 4 is heated, the film forming reaction on the surface of the base material 4 can be promoted.

  Next, an AC voltage of 5 kV to 50 kV is applied to the application electrode 2 by the high-voltage pulse power source 1 in an atmospheric pressure atmosphere, and a positive DC bias voltage of DC 200 V to 10000 V is further applied by the DC power source 7. A glow discharge plasma is generated between the application electrode 2 and the holding electrode 6. Since the DC bias voltage is applied, positive ions are easily attracted to the surface of the base material 4, and the collision energy to the surface of the base material 4 increases. Therefore, the plasma reaction on the surface of the substrate 4 is activated.

  Under such conditions, an amorphous hard carbon film is formed on the surface of the substrate 4 by supplying and exhausting the source gas while performing plasma discharge in an atmospheric pressure atmosphere. The thickness of the deposited film is determined by the time for performing the plasma treatment. Therefore, plasma treatment may be performed until an amorphous hard carbon film having a required thickness is formed.

  In this first embodiment, the amorphous hard carbon film forming apparatus of the present invention comprises the holding electrode 6 described above, the electrode body including the application electrode 2, the voltage application means 20, and the DC bias voltage application. It comprises means 30, heating means 5, source gas supply means, and exhaust means.

[Second Example]
FIG. 2 is a partial sectional side view of the second embodiment of the amorphous hard carbon film forming apparatus of the present invention. FIG. 3 is a partial plan view seen from a cut surface cut along the section XX ′ in FIG.

  2 and 3 illustrate a part of the amorphous hard carbon film deposition apparatus 200 of the present invention. In a part of the film forming apparatus 200, a holding electrode, an electrode body including an application electrode, a heating unit, a source gas supply unit, and an exhaust unit are shown. Since parts other than those shown in FIGS. 2 and 3 are the same as those described with reference to FIG. 1, description thereof will be omitted.

  As shown in FIGS. 2 and 3, the plate-like base material 4 having a length of 30 mm, a width of 30 mm, and a height of 3 mm is accommodated in the recess so as to have substantially the same height as the surface of the holding electrode 6. A plate-like holding electrode 6 having a length of 70 mm, a width of 70 mm, and a height of 5 mm is sandwiched between the heat-resistant structural members 12. A heating device 5 is disposed on the back surface of the holding electrode 6.

  The heating device 5 includes a plate heater and a thermocouple, and can control the temperature of the substrate 4. A cooling device 11 is disposed on the back surface of the heating device 5 in order to cool the base material 4 after the film forming process. As the cooling device 11, a jig having a water cooling structure can be preferably used.

  Since the base material 4 is heated and cooled in this way, the heat-resistant structural material 12 that sandwiches the base material 4 is preferably a ceramic that has insulating properties and heat resistance of 300 ° C. or more and has little dimensional change. Used.

  The plate-like application electrode 2 is sandwiched between heat resistant structural members 12. A dielectric 3 is disposed on the surface of the application electrode 2 facing the substrate 4. At this time, an alumina plate is used as the dielectric 3, but the dielectric 3 does not have to be used if an electrode sprayed with a ceramic material is used as the application electrode 2. A cooling device 11 is disposed on the back surface of the application electrode 2 to keep the application electrode at a low temperature.

  A gas supply nozzle 13 is attached to one end of the heat-resistant structural material 12 on the application electrode 2 side and the heat-resistant structural material 12 on the holding electrode 6 side. An exhaust nozzle 14 is attached to the end of the heat-resistant structural material 12 opposite to the gas supply nozzle 13 side.

  As shown in FIG. 3, a spacer 17 is sandwiched between two ends of the heat-resistant structural material to which the gas supply nozzle 13 and the exhaust nozzle 14 are not attached. The thickness of the spacer 17 can set the discharge gap distance between the electrodes. For the spacer 17, ceramics having insulating properties and heat resistance of 300 ° C. or higher is preferably used.

  The gas supply nozzle 13 and the exhaust nozzle 14 are nozzles wider than the base material 4 in order to supply the source gas uniformly in a line shape. In the film forming apparatus 200, the gas supply nozzle 13 and the exhaust nozzle 14 have a width of 150 mm.

  The gas supply nozzle 13 is connected to a source gas cylinder (not shown), and the flow rate of the source gas is controlled by a control valve of the source gas cylinder. The exhaust nozzle 14 is connected to an exhaust pump (not shown), and the exhaust speed is controlled by the exhaust pump.

  Source gas is introduced from the gas supply nozzle 13 in the direction of arrow A between the electrodes. In order to create a uniform flow, a flow meter (not shown) is provided downstream of the exhaust nozzle 14. The exhaust flow rate of the exhaust pump can be adjusted while looking at the numerical value of the flow meter.

  At this time, it is considered that the raw material gas rectified by the gas supply nozzle is in a laminar flow state in the atmosphere of the base material 4.

  A hard amorphous hard carbon film can be formed on the surface of the substrate by performing plasma treatment in an atmospheric pressure atmosphere using such a film forming apparatus 200. In addition, since the plasma treatment can be performed under an atmospheric pressure atmosphere, a vacuum apparatus is not required, and the film formation speed is high, so that the film formation apparatus has extremely low equipment costs and running costs.

[Third embodiment]
FIG. 4 is a partial sectional side view of the third embodiment of the amorphous hard carbon film forming apparatus of the present invention. FIG. 5 is a partial plan view of FIG. 4 as viewed from above.

  4 and 5 illustrate a part of an amorphous hard carbon film deposition apparatus 300 according to the present invention. In a part of the film forming apparatus 300, a holding electrode, an electrode body including an application electrode, a heating unit, a source gas supply unit, an exhaust unit, and a moving unit are shown.

  The film forming apparatus 300 generates glow discharge plasma between the holding electrode 6 holding the plurality of substrates 4 and the electrode body 40, and moves the holding electrode 6 in the direction of arrow C shown in FIG. This is an apparatus for forming an amorphous hard carbon film on the surface of the material 4.

  The film forming apparatus 300 can have a circuit configuration similar to the circuit configuration described in FIG. Since parts other than those shown in FIGS. 4 and 5 are the same as those described with reference to FIG. 1, description thereof will be omitted.

  The holding electrode 6 has a plurality of recesses for accommodating the plurality of base materials 4. The holding electrode 6 is translated in the direction of arrow C by moving means (not shown). In order to smoothly move the holding electrode 6, a heat-resistant lubricant 15 is disposed on the back surface of the holding electrode 6. As the lubricant 15, a film, a sheet, a liquid and a powder are preferably used.

  Heating means 5 for heating the base material 4 is disposed on the back surface of the holding electrode 6 via the lubricant 15. Further, in the direction of arrow C, a cooling device 11 is disposed via a heat-resistant structural member 12 downstream of the heating means 5 in order to cool the substrate 4 after the film forming process.

  The electrode body 40 includes a plurality of application electrodes 2 whose surfaces on the base material side are covered with the dielectric 3, a gas supply port 130 disposed between the application electrodes 2, and the application electrode 2 of the gas supply port 130. The exhaust port 140 is provided at least on both sides.

  The gas supply port 130 and the exhaust port 140 are slit-shaped. The width of the slit is preferably about twice the discharge gap distance. The slit length should just be the length which can coat | cover the surface of the base material which forms an amorphous | non-crystalline hard carbon film. 4 and 5, the gas supply port 130 and the exhaust port 140 have a slit shape with a width of 1 mm and a length of 150 mm.

  Although not shown, the gas supply port 130 is connected to a cylinder or the like for supplying a raw material gas, and the flow rate is controlled by a control valve. The exhaust port 140 is connected to an exhaust pump (not shown) and is sucked by the exhaust pump to exhaust the source gas.

  In FIG. 4, the flow of the source gas is indicated by arrows. The source gas blown out from the gas supply port 130 toward the holding electrode 6 in the direction of arrow A is sucked up in the direction of arrow B from the exhaust ports 140 provided on both sides of the gas supply port 130. For this reason, a new source gas always flows between the application electrode 2 and the holding electrode 6 in a certain direction. In addition, a uniform line-shaped gas flow can be formed in a narrower range. Further, convection of a difficult source gas is likely to occur under an atmospheric pressure atmosphere, the source gas is evenly diffused, and an amorphous hard carbon film can be uniformly formed on the surface of the substrate.

  The application electrode 2 has a plate-like shape, and the length may be longer than the length of the substrate 4, and the width and height are not particularly limited. The surface of the application electrode 2 is covered with a dielectric 3 with a thickness of 1 mm on the surface on the holding electrode 6 side. The two application electrodes 2 are disposed at a position sandwiched between the slit-shaped gas supply port 130 and the two exhaust ports 140 on both sides. A cooling device 11 is disposed on the back surface of the application electrode 2 in order to keep the application electrode 2 at a low temperature. The application electrode 2 is held by the heat-resistant structural material 12 to form an electrode body 40.

  As shown in FIG. 5, the holding electrode 6 is provided with spacers 16 at opposite ends that are not in the moving direction. The thickness of the spacer 16 can set the discharge gap distance between the electrodes. For the spacer 16, ceramics having insulating properties and heat resistance of 300 ° C. or higher is preferably used.

  While moving the holding electrode 6 in the direction of arrow C under such conditions, a DC bias voltage is applied to the holding electrode 6 to perform plasma discharge, and supply and exhaust of the source gas to the surface of the substrate 4. An amorphous hard carbon film is formed. Further, the film formation reaction on the surface can be promoted by heating the substrate. Further, the plurality of base materials 4 are sequentially formed by moving the holding electrode 6 relatively. The thickness of the film formed on the substrate 4 is determined by the moving speed of the holding electrode 6. Therefore, a moving speed that provides the required film thickness may be used.

  A hard amorphous hard carbon film can be formed on the surface of the substrate by performing plasma treatment in an atmospheric pressure atmosphere using such a film forming apparatus 300. In addition, since plasma processing can be performed under an atmospheric pressure atmosphere, a vacuum apparatus is not required, the film forming speed is high, and the line apparatus is capable of continuous processing, so that the equipment cost and running cost are extremely low. It becomes a membrane device.

[Test example]
An amorphous hard carbon film was formed using the method shown in FIGS.

  A plate made of high-speed steel SKH51 and having a length of 30 mm, a width of 30 mm, and a thickness of 3 mm was used as the substrate 4. The holding electrode 6 is a copper flat plate having a length of 70 mm, a width of 70 mm, and a thickness of 5 mm, and has a recess capable of holding the base material 4. The base material 4 is held in the recess.

  On the back surface of the holding electrode 6, a plate-like heater and a thermocouple are disposed as the heating means 5.

  As the plate-like heater and thermocouple, a high-temperature planar heating element “Super Rapid” manufactured by Sakaguchi Electric Heat and a sheath thermocouple were used.

  The application electrode 2 has a plate shape having a length of 70 mm, a width of 70 mm, and a thickness of 5 mm. On the surface of the application electrode 2 facing the base material, an alumina plate having a thickness of 1 mm is disposed as the dielectric 3.

  Both the gas supply nozzle 13 and the exhaust nozzle 14 have a width of 150 mm. The gas supply nozzle 13 is connected to a gas cylinder that supplies a source gas. The exhaust nozzle 14 is connected to an exhaust pump.

  A high voltage pulse power source 1 is connected to the application electrode 2 and applied. Further, a positive DC voltage is further applied to the application electrode 2 from a DC power source 7. The holding electrode 6 is grounded.

  As the DC power source 7, a DC high-voltage power source manufactured by Grassman Japan High Voltage was used.

  Base material temperature 200 ° C., discharge gap distance 0.5 mm, AC power supply voltage 20 kV, AC power supply frequency 10 kHz, DC power supply voltage 4000 V, raw material mixed gas ratio, helium gas: acetylene gas = 95: 5 constant, gas flow rate 1200 mm / sec. Performed under conditions. The film thickness of the amorphous hard carbon film could be controlled by controlling the application time. These series of film formation methods were performed in an atmosphere open to atmospheric pressure, and film formation was performed in an environment of approximately 101 kPa.

  As a result, an amorphous hard carbon film having a thickness of 2 μm was uniformly formed on the substrate in an application time of 1 minute to 2 minutes. This is designated as Test Example 1.

  Further, as a comparative example, film formation was performed in the case where a DC bias voltage was not applied by changing the film formation conditions.

  The film forming conditions were the same as those described above except that the substrate temperature was 30 ° C., the DC power supply voltage was 0 V, and the gas flow rate was 100 mm / sec. As a result, an amorphous hard carbon film having a thickness of 2 μm was uniformly formed on the substrate in an application time of 1 minute to 2 minutes. This is designated as Test Example 2.

  The films of Test Example 1 and Test Example 2 were evaluated.

<Film hardness evaluation device>
The film hardness was measured by the nanoindentation method. The nanoindenter used was a Toribo Scope manufactured by HYSITRON, which was attached to an atomic force microscope (SPM9500J2 manufactured by SHIMADZU). According to the nanoindentation method, the hardness of the thin film itself can be measured without being affected by the base material.

  In Test Example 1, the film hardness was 5 ± 2 GPa, and the film hardness of Test Example 2 was 0.4 ± 0.1 GPa. It was found that Test Example 1 was significantly improved in hardness compared to Test Example 2. .

<Elemental analysis>
The elemental composition ratio was analyzed by the ERDA recoil detection method and RBS (Rutherford backscattering analysis).

  In Test Example 1, the element composition ratio (%) was 55% carbon, 41% hydrogen, and 4% other (oxygen, nitrogen, etc.), whereas in Test Example 2, the element composition ratio (%) was 41% carbon. %, Hydrogen 53%, and other (oxygen, nitrogen, etc.) 6%. From this, it can be seen that Test Example 1 has a higher carbon ratio than Test Example 2.

<Bonding>
The binding state was analyzed using FT-IR.

  From the results of FT-IR, it was confirmed that the amount of carbon double bonds and C—H bonds observed in Test Example 2 decreased in Test Example 1. It is thought that there were many strong carbon bonds as bonds.

The measured film hardness of Test Example 1 is equivalent to that of the SiO ₂ film. Conventionally, such a hard film cannot be obtained by using a hydrocarbon gas as a raw material in an atmospheric pressure atmosphere. By having this hardness, this amorphous hard carbon film can be applied to a portion exhibiting high sliding performance. Further, since it has a hardness equivalent to that of the SiO ₂ film, it can also be used as a hard coat application in which a resin or the like has been silica-coated so far.

It is a schematic explanatory drawing which shows the 1st Example of the film-forming apparatus of the amorphous | non-crystalline hard carbon film of this invention. It is a partial sectional side view of the 2nd Example of the film-forming apparatus of the amorphous | non-crystalline hard carbon film of this invention. It is the fragmentary top view seen from the cut surface cut | disconnected by the XX 'cross section in FIG. It is a partial sectional side view of the 3rd Example of the film-forming apparatus of the amorphous | non-crystalline hard carbon film of this invention. It is the fragmentary top view which looked at FIG. 4 from the top.

Explanation of symbols

1, high-voltage pulse power supply, 2, application electrode, 3, dielectric, 4, substrate, 5, heating means,
6, holding electrode, 7, DC power supply, 8, filter coil, 9, second capacitor,
10, first capacitor 11, cooling device 12, heat-resistant structural material 13, gas supply nozzle,
14, exhaust nozzle, 15, lubricant, 16, 17, spacer, 20, voltage applying means,
30, DC bias voltage applying means, 40, electrode body, 100, 200, 300, film forming apparatus,
130, gas supply port, 140, exhaust port.

Claims (3)

A holding electrode for holding the substrate;
An electrode body positioned opposite to the holding electrode and having a plurality of application electrodes;
Voltage application means for applying an alternating voltage to the application electrode to generate glow discharge plasma in an atmospheric pressure atmosphere between the substrate held by the holding electrode and the electrode body;
DC bias voltage applying means for generating a DC bias voltage between the electrode body and the holding electrode;
A raw material gas supply means for supplying a raw material gas for forming an amorphous hard carbon film on the surface of the substrate between the holding electrode and the electrode body;
Exhaust means for discharging exhaust gas from between the holding electrode and the electrode body;
A heating means disposed on the back surface of the holding electrode for heating the substrate held by the holding electrode;
Moving means for relatively moving the holding electrode and the electrode body;
Have
The source gas supply means has a gas supply port for supplying the source gas between the holding electrode and the electrode body from between two adjacent application electrodes, and the exhaust means An amorphous hard carbon film forming apparatus characterized by having exhaust ports on both outer sides of an application electrode. 2. The amorphous hard carbon film forming apparatus according to claim 1 , wherein the gas supply port and the exhaust port have a slit shape longer than a length of the base material. The applying electrode is film-forming apparatus of the amorphous hard carbon film according to claim 1 or 2, the surface thereof is covered with a dielectric.

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