JP4653964B2 - DLC film forming method and DLC film-formed product - Google Patents

Description

  The present invention relates to a method for forming a diamond-like carbon (DLC) film on the surface of an industrial part such as a prototype mold, a tool, a hard disk, a semiconductor manufacturing part and an automobile part, and the formation of the diamond-like carbon. More specifically, the film material is based on a pulsed plasma ion implantation and deposition method (PBIID).

  Since DLC has characteristics such as low friction, wear resistance, and corrosion resistance, it has been widely used as a protective coating for various molds, tools, hard disks and various sliding parts in automobiles. Yes.

  Conventionally, as a method of forming a DLC film, a plasma CVD method is generally used. In this method, a raw material gas is introduced into a vacuum chamber, and then a high frequency discharge (a capacitively coupled plasma excitation method and an inductively coupled plasma) is used. The DLC film is formed on the substrate by generating active radicals and ions by an excitation method or the like or microwave discharge.

  More specifically, for example, in the plasma CVD method using high-frequency discharge, as shown in FIG. 10, recesses 52 facing each other are provided on both side walls 51 a of the chamber 51, and the electrodes 53 and 54 are provided in the recess 52. The plasma generating high frequency power supply 55 is connected to the electrode 54 on one side thereof, while the conductor 57 is suspended from the feedthrough 56 attached to the center of the upper wall 51b of the chamber 51, and the base material 58 is attached to the tip thereof. By attaching, a base material 58 is arranged between the electrodes 53, 54, and then a high voltage pulse generating power source 59 is connected to the feedthrough 56, and a chamber 51 is connected via a valve 62 by a vacuum device 61. After the inside is evacuated, the source gas is introduced into the chamber 51 from the gas supply device 63 via the valve 64, and the electrode 5 is supplied from the high frequency power source 55 for plasma generation. The plasma is generated in the chamber 51 by applying high-frequency power to the chamber 51, while a negative high voltage pulse is finally applied to the substrate 58 through the conductor 57 from the power source 59 for generating a high voltage pulse. 58, a DLC film was formed on the surface.

  However, in the case of the DLC film formation described above, plasma is generated in the vicinity of the electrode 54 on one side of the chamber 51, and plasma is generated at a position away from the base material 58. Therefore, a separate means for transporting the plasma to the position of the base material 58 is required, and as a result of the plasma diverges during the transport and the plasma density is lowered, there is a problem that the ion implantation efficiency by the plasma is low.

  Furthermore, when the base material 58 has a hollow shape having the recess 58a, the plasma diffuses and reaches from the electrodes (antennas) 53 and 54, so that the plasma is not uniformly distributed along the shape of the base material 58. Moreover, it is difficult for plasma to diffuse and penetrate inside the base material 58. If the plasma is forced to enter the inside of the base material 58, the plasma generation is continuous. Therefore, depending on the gas pressure, pulse voltage value, and pulse width, the so-called hollow cathode phenomenon occurs, and the recess Since the plasma density in 58a is much higher than the plasma density around the outside of the substrate 58, as shown in FIG. 11, the DLC film 60 is formed thick especially at the bottom of the recess 58a. There is a problem in that the DLC film 60 is thinly formed on the side wall portion 58a and uniform DLC film formation cannot be performed on both the inner and outer peripheries.

  In addition, in order to improve the adhesion of the DLC film by plasma CVD, an intermediate layer composed of a single component or a plurality of components is provided between the substrate and the DLC film, or a fine heat treatment or sputtering is separately performed on the substrate. Although uneven surface processing or the like is also performed, in these methods, the film formation process becomes complicated and it takes a long time to form the film, and it is difficult to thicken the DLC film itself, and the film is thickly formed. In this case, there is a drawback that the DLC film is easily peeled off due to the residual stress in the film.

  Furthermore, when the base material is a low melting point alloy such as a zinc alloy or an aluminum alloy, the base material itself may be altered or deformed (strained) due to a temperature increase accompanying auxiliary heating or plasma generation.

  In the conventional DLC film formation, in order to uniformly form the DLC film on the surface of the base material, it is necessary to appropriately rotate the base material during the film formation. Also, ion implantation to the base material and DLC film formation are required. Therefore, there is a problem that it takes a lot of time and labor to form the DLC film because it is necessary to transfer the base material to the DLC film forming apparatus after the ion implantation.

  In addition, in a metal member coated with a DLC film by plasma polymerization in a gas atmosphere containing hydrocarbon, an intermediate layer composed of a lower layer mainly composed of chromium or titanium and an upper layer mainly composed of silicon or germanium A metal member interposed between a metal member and the DLC film is known.

  However, in the case of the DLC film through the intermediate layer in the metal member, since the bias voltage is low and ion energy is not effectively used, the metal member, the intermediate layer, and the DLC film as a base material have a clear laminated structure. Therefore, the coating strength of the DLC film on the metal member as the base material is low. Therefore, when the metal member is used for a sliding part such as a piston, the DLC film may be damaged and peeled off from the metal member. .

  The applicant of the present application previously applied surface modification by applying a high-frequency pulse and a negative high-voltage pulse to a substrate in a superimposed manner by a plasma generation power source and a high-voltage pulse generation power source through a common feedthrough. We are developing quality equipment and reforming methods.

In addition, the patent application generates plasma along the outer shape of the base material, while applying a negative high voltage pulse to the base material, thereby attracting ions in the plasma and injecting the base material into the base material. Injecting and attracting deposition to form a thin film on the substrate and attracting collision to sputter-clean the substrate, the present invention uses the apparatus in the patent application to thicken the DLC film on the substrate surface with high adhesion. It is an object of the present invention to provide a DLC film forming method and a DLC film-formed product capable of forming a film and reducing the residual stress in the film.
JP 2001-26887 A Japanese Patent No. 19408883

  The method for forming a DLC film according to claim 1, wherein the DLC film is formed on the surface of the base material by a combined process using an ion implantation process and a film forming process by pulse plasma using at least one hydrocarbon gas. It is a technical feature to form a film.

  In this specification, “DLC” means diamond-like carbon.

  The base material includes all finished products and parts that require DLC film formation, and specifically include prototype molds, tools, hard disks, semiconductor manufacturing parts, golf club heads, automobile parts, and the like. .

  The base material may be an insulating material such as plastic, rubber, and ceramics in addition to a conductive material such as metal.

  According to a second aspect of the present invention, there is provided a DLC film forming method according to the first aspect, wherein a surface adjustment process using pulsed plasma is provided before the combined process.

  The DLC film forming method according to claim 3, wherein a plasma generating high frequency power source and a high voltage pulse generating power source are connected to a base material in a chamber through a common feedthrough, and the plasma generating A high-frequency pulse is applied to the substrate from a high-frequency power source to generate plasma around the outer shape of the substrate, and a negative high-voltage pulse is applied to the substrate from the high-voltage pulse generating power source in the plasma or afterglow plasma. And at least one application of the high-frequency pulse and the application of the high-voltage pulse, and the ion implantation process and the film-forming process using the pulsed plasma according to claim 1, or further according to claim 2. A surface conditioning process is performed.

  The number of repetitions of the application of the high frequency pulse and the application of the high voltage pulse is, for example, about 100 times / second to 5000 times / second.

  The DLC film forming method according to claim 4 is the same as the film forming method according to claim 3, wherein the high-frequency pulse width is a short pulse of 2 to 200 μs and the high voltage pulse width is a short pulse of 0.2 to 50 μs. In addition, a high voltage pulse is applied during the application of the high frequency pulse or immediately after the application to 300 μs, and as described in claim 5, the high frequency pulse width is set to a short pulse of 5 to 20 μs, and the high voltage pulse is applied. More preferably, the pulse width is a short pulse of 1 to 5 μs, and the high voltage pulse is applied immediately after the application of the high-frequency pulse to 100 μs.

  The DLC film formation method according to claim 6 is the same as the film formation method according to any one of claims 3 to 5, wherein the ion implantation process using pulsed plasma and a high voltage in the initial film formation stage are used. The voltage of the pulse is set higher than the voltage of the high voltage pulse in the film forming stage after the initial film forming stage, and the number of repetitions of the application of the high frequency pulse and the high voltage pulse is set to the film forming stage after the initial film forming stage. It is a technical feature to do more.

  The film forming method according to claim 7 is the same as the film forming method according to claim 6, wherein the voltage of the high voltage pulse in the pulse plasma ion implantation process and the initial film forming stage is set to 20 kV, and the film forming process in the subsequent film forming stage is performed. The voltage is set to 10 kV.

  A method for forming a DLC film according to claim 8 is the same as the method for forming a DLC film according to claim 6 or 7, wherein silane coupling is performed as an impurity at least from a later stage of a pulse plasma ion implantation process to an earlier stage of an initial film formation stage. It is characterized by adding a preparation. Examples of the silane coupling agent include alkoxide-based agents such as hexamethyldisiloxane (HMDSO), tetramethylsilane (TMS), tetraethoxysilicon (TEOS), and the like. Siloxane is most preferred, and in this case, the gas pressure in the chamber at the initial film formation stage in the film formation process is 0.3 to 0.5 Pa, and the gas pressure at the subsequent film formation stage is 0.8 to 3 Pa is preferable.

  A method for forming a DLC film according to claim 10 is the film forming method according to any one of claims 2 to 9, wherein argon and methane or further hydrogen is mixed as a surface conditioning gas. Gas, methane gas is used as a pulse plasma ion implantation gas, and one or more gases selected from the group consisting of acetylene, propane, butane, hexane, benzene, chlorobenzene, and toluene are used as a film forming gas. It is what.

  That is, the surface adjustment is performed by cleaning the substrate surface by molecular collision in the argon gas having a high molecular weight among the surface adjustment gases, and by attaching carbon atoms and hydrogen atoms in the methane gas to the substrate surface.

  Then, methane gas is used as a pulse plasma ion implantation gas, and carbon single atoms are injected into the substrate, and then a film is formed by colliding two or more carbon atoms such as acetylene and propane with the substrate as a film forming gas. It is.

  The DLC film forming method according to claim 11 is the film forming method according to any one of claims 2 to 10, wherein nitrogen gas is used before methane gas is used as the pulse plasma ion implantation gas. It is characterized by this. In this case, the nitrogen atom implanted into the substrate has a function of preventing the subsequently implanted carbon atoms from diffusing into the substrate.

  The film forming method of the DLC film according to claim 12 is the film forming method according to any one of claims 1 to 11, wherein the base material is a low melting point alloy. In the film forming method of the present invention, each process of ion implantation and DLC film formation is basically performed by pulsed plasma, so that the temperature of the substrate during film formation can be kept low, and DLC into a low melting point alloy is achieved. Film formation can be realized.

  The method for forming a DLC film according to claim 13 is the film forming method according to any one of claims 1 to 12, wherein the substrate is an insulating material. Each treatment is performed while being held in a holder made of a conductive material.

  The DLC film-formed product according to claim 14 is a DLC film-formed product in which a DLC film is directly formed on the surface of the substrate, and carbon atoms are injected from the surface of the substrate to a predetermined depth, An inclined layer of implanted atoms and carbon atoms is formed at the interface with the DLC film, and the implanted atoms in the base material and the carbon atoms in the DLC film are covalently bonded to align the carbon atoms in the DLC film. It is what.

  The DLC film-formed product according to claim 15 is the film-formed product according to claim 14, wherein the base material is a zinc alloy, an aluminum alloy, a magnesium alloy or iron.

  According to a sixteenth aspect of the present invention, there is provided a method for forming a DLC film according to the third aspect, wherein an ion implantation process using a pulse plasma and a film forming process are used, and a titanium ceramic film is interposed on the surface of the substrate. A method for forming a DLC film, in which an organic titanium arcoside is used as a titanium ceramic film forming gas, titanium is injected into a base material, and then a titanium ceramic film is formed on the surface of the base material, and then the DLC film A hydrocarbon gas is used as a forming gas, carbon is injected into the titanium ceramic film, and then a DLC film is formed on the titanium ceramic film.

  Examples of the hydrocarbon gas include one or more gases selected from the group consisting of methane, ethylene, acetylene, propane, butane, hexane, benzene, chlorobenzene, toluene, and the like.

  The present invention according to claim 17 is the method for forming a DLC film according to claim 3, wherein a titanium ceramic film and a silicon ceramic film are formed on the surface of the substrate by using an ion implantation process and a film forming process by pulse plasma. A method of forming a DLC film through the method, using an organic titanium alkoxide as a titanium ceramic film forming gas, injecting titanium into the base material, forming a titanium ceramic film on the surface of the base material, Further, a silane coupling agent is used as a silicon ceramic film forming gas, silicon is injected into the titanium ceramic film, a silicon ceramic film is formed on the titanium ceramic film, and then a DLC film forming gas is formed. A hydrocarbon-based gas is used, and after carbon is injected into the silicon ceramic film, DLC is formed on the silicon ceramic film. The is characterized in that film formation.

  The present invention described in claim 18 relates to the method for forming a DLC film according to claim 16 or claim 17, wherein the voltage of the high voltage pulse in the ion implantation process by the pulse plasma and the initial film formation stage is set after the initial film formation stage. The voltage is set higher than the voltage of the high voltage pulse in the film formation stage, and the repetition number of the application of the high frequency pulse and the high voltage pulse is increased in the film formation stage after the initial film formation stage. Is.

  The present invention according to claim 19 is characterized in that in the method for forming a DLC film according to any one of claims 16 to 18, nitrogen is implanted before titanium is implanted into the substrate. To do.

  The present invention according to claim 20 is characterized in that, in the method for forming a DLC film according to any one of claims 16 to 19, the organotitanium alkoxide is tetraisopropoxytitanium. To do.

  In addition to the tetraisopropoxytitanium described above, tetra-n-butoxytitanium and the like are also suitable as the organic titanium alkoxide.

  The present invention according to claim 21 relates to the method for forming a DLC film according to any one of claims 16 to 20, wherein the silane coupling agent is tetramethylsilane or hexamethyldisiloxane. It is characterized by this.

  The present invention according to claim 22 is a DLC film-formed product in which a DLC film is formed on the surface of a base material via a titanium ceramic film, and the titanium ceramic film is inclined from the base material to the surface of the base material. The DLC film is formed in an inclined shape from the titanium ceramic film to the surface thereof, and the carbon atoms are present in an inclined form from the base material to the DLC film.

  According to a twenty-third aspect of the present invention, in the DLC film-formed product according to the twenty-second aspect, the titanium ceramic film is TiOCx.

  The present invention according to claim 24 is a DLC film-formed product in which a DLC film is formed on a surface of a base material via a titanium ceramic film and a silicon ceramic film. A film is formed in an inclined shape, a silicon ceramic film is formed in an inclined shape from the titanium ceramic film to the surface thereof, a DLC film is formed in an inclined shape from the silicon ceramic film to the surface thereof, and Carbon atoms are present in an inclined manner from the substrate to the DLC film.

  According to a twenty-fifth aspect of the present invention, the DLC film according to the twenty-fourth aspect is characterized in that the titanium ceramic film is TiOCx and the silicon ceramic film is SiOCx.

  The present invention according to claim 26 is the DLC film-formed product according to any one of claims 22 to 25, wherein the base material is copper, brass, high carbon steel, carburized steel, magnesium alloy or aluminum. It is an alloy.

  The DLC film deposition method according to the present invention generates a high-density high-frequency pulse plasma around the outer shape of the substrate, and applies a negative high-voltage pulse at least once in the plasma or in the afterglow plasma. In addition, since the high frequency pulse and the high voltage pulse are repeatedly applied, ion implantation and DLC film formation are continuously performed on the base material. In comparison, the DLC film can be formed efficiently, and by using the pulse plasma, the DLC film can be easily formed on a low melting point alloy such as an aluminum alloy or a zinc alloy.

  Furthermore, according to the DLC film forming method of the present invention, ion implantation and film formation can be performed continuously with one apparatus without rotating the substrate, compared with the conventional DLC film forming method. As a result, work efficiency can be greatly improved.

  In addition, since the DLC film formation method of the present invention is ion implantation and film formation by a short pulse, even a base material having a recess hardly causes a hollow cathode phenomenon and can form a uniform DLC film.

  In addition, according to the DLC film forming method of the present invention in which hexamethyldisiloxane is added as an impurity at least from the latter stage of the pulse plasma injection process to the first stage of the initial film forming stage, the DLC film is formed by —C—Si—O— bonds. The adhesion to the substrate can be further improved.

  In addition, according to the present invention in which nitrogen gas is used before the methane gas is used as the ion implantation gas, by injecting nitrogen atoms into the base material, carbon atoms subsequently injected into the base material Diffusion can be effectively prevented.

  Moreover, according to the DLC film-forming method of Claims 1-13, forming a DLC film firmly directly on the base-material surface, without forming an intermediate | middle layer between a base-material and a DLC film. In addition, since the residual stress of the DLC film can be made very low as compared with the conventional method, the DLC film is hardly peeled off.

  In the DLC film according to claim 14 and claim 15, carbon atoms are implanted from the surface of the substrate to a predetermined depth, and implanted atoms and carbon atoms (DLC film component) are formed at the interface between the substrate and the DLC film. Are formed, the implanted atoms in the base material and the carbon atoms of the DLC film are covalently bonded, and the carbon atoms in the DLC film are aligned. Since the high adhesion of the DLC film can be obtained and the residual stress of the DLC film is reduced due to the alignment of the carbon atoms, it can be expected to be widely used as a prototype mold or various sliding parts.

  According to the DLC film forming method of claims 16 to 21, particularly DLC film formation on an iron-based metal can be performed firmly, and high carbon steel, carburized steel, or There is a special advantage that DLC film formation on copper, brass, magnesium alloy or the like can be performed easily and firmly.

  According to the DLC film-formed product of claims 22 to 26, since the titanium ceramic film, or further the silicon ceramic film, and the DLC film are sequentially formed on the base material in an inclined manner, the base material The adhesion strength of the DLC film is very high.

  Further, in the DLC film-formed product according to claim 23 and claim 25, a strong DLC film performance utilizing the bonding force of oxygen such as TiOCX and SiOCX can be expected.

  Next, embodiments of the present invention will be described with reference to the drawings.

  First, the configuration of an apparatus for forming a DLC film will be described.

  As shown in FIG. 1, an apparatus for forming a DLC film includes a chamber 2 that houses a base material 1, a gas supply pipe 3 that is connected to a lower wall 2 a of the chamber 2, and a gas supply pipe 3. A gas introduction valve 4 attached to the front end portion, an exhaust pipe 5 connected to one side wall 2b of the chamber 2, an exhaust valve 6 attached to the front end portion of the exhaust pipe 5, and the chamber 2 A feedthrough 8 attached to the upper wall 10 and connected to the base material 1 via the conductor 7, a superimposing device 9 described later connected to the upper part of the feedthrough 8, and plasma generation connected to the superimposing device 9 Power supply 11 and high voltage pulse generating power supply 12, and plasma generating power supply (high frequency power supply) 11 and CPU 13 for controlling high voltage pulse generating power supply 12.

  A vacuum device 14 for evacuating the chamber 2 is connected to the base end side of the exhaust pipe 5.

  A gas supply tank 15 is connected to the proximal end side of the gas supply pipe 3, and various gases necessary for DLC film formation described later are individually stored in the gas supply tank 15. The gas supply from the gas supply tank 15 is performed using a mass flow control (not shown).

  As shown in FIG. 2, the superimposing device 9 couples the feedthrough 8 and the high voltage pulse generating power source 12 and prevents mutual interference between the plasma generating power source 11 and the high voltage pulse generating power source 12. And a matching circuit unit 17 for matching the impedance between the plasma generating power source 11 and the substrate 1.

  The coupling / mutual interference blocking circuit unit 16 causes arc discharge by a high voltage pulse, and the gap G1 for conducting the circuit and the high frequency power from the plasma generating power source 11 affect the high voltage pulse generating power source 12. The diode D and the coil L1 for preventing the high voltage pulse, and the resistor R and the protective gap G2 for preventing the high voltage pulse of the high voltage pulse generating power source 12 from affecting the plasma generating power source 11 are provided. The gap G1 may be short-circuited when the pulse application voltage is low. In the coupling / mutual interference blocking circuit unit 16 in the superimposing device 9, the cathode side of the diode D is connected to the high voltage pulse generating power source 12. Further, the non-ground side end of the resistor R is connected to the plasma generating power source 11 by the coaxial cable 18. The diode D may be omitted.

  The matching circuit unit 17 includes a resonance variable capacitor C1, an impedance conversion capacitor C2, a high voltage capacitor C3, and a coil L2. Since the capacitor C2 is connected in parallel with the resistor R, the non-grounded end is also connected to the plasma generating power supply 11 through the coaxial cable 18.

  The terminal on the gap G1 side of the high voltage capacitor C3 is connected to the feedthrough 8 and the gap G1 conductor on the substrate 1 side.

  The plasma generating power source 11 applies a high frequency pulse to the substrate 1 based on control by the CPU 13. The high voltage pulse generating power source 12 applies a negative high voltage pulse to the substrate 1 based on control by the CPU 13.

  (Embodiment 1)

  An embodiment in which DLC film formation is performed on the surface of a base material 1 made of a zinc alloy using the film formation apparatus described above will be described.

  Step 1: First, after the inside of the chamber 2 is brought into a high vacuum state by the vacuum device 14, a gas in which argon and methane are mixed by 50% is introduced into the chamber 2 from the gas supply tank 15.

  Next, after applying a high frequency pulse with a pulse width of 25 μs to the substrate 1, a high voltage pulse with a pulse width of 5 μs is applied once to the substrate 1 at a voltage of 10 kV immediately after the application to 65 μs (FIG. 3) is repeated about 2000 times / second, and this operation is performed for about 15 minutes to adjust the surface of the substrate 1.

  Step 2: Next, nitrogen gas is introduced into the chamber 2 (the degree of vacuum is 0.3 Pa) from the gas supply tank 15.

  Then, after applying a high frequency pulse with a pulse width of 25 μs to the substrate 1, a high voltage pulse with a pulse width of 5 μs is applied once to the substrate 1 at a voltage of 20 kV immediately after the application to 65 μs. By repeating this operation for 1000 times / second and for about 20 minutes, nitrogen atoms are injected to a predetermined depth in the substrate 1.

  Step 3: Next, methane gas is introduced into the chamber 2 (vacuum degree 0.4 Pa) from the gas supply tank 15.

  Then, after applying a high frequency pulse with a pulse width of 25 μs to the substrate 1, a high voltage pulse with a pulse width of 5 μs is applied once to the substrate 1 at a voltage of 20 kV immediately after the application to 65 μs. By repeating this operation 1000 times / second and performing this operation for about 30 minutes, carbon atoms are injected after nitrogen atoms previously injected into the substrate 1.

  In addition, about 10 minutes before the end of the operation, gaseous hexamethyldisiloxane is introduced into the chamber 2.

  Step 4 1: Next, acetylene gas is introduced from the gas supply tank 15 into the chamber 2 (degree of vacuum 0.4 Pa).

  Then, after applying a high frequency pulse with a pulse width of 25 μs to the substrate 1, a high voltage pulse with a pulse width of 5 μs is applied once to the substrate 1 at a voltage of 20 kV immediately after the application to 65 μs. By repeating this operation 1000 times / second and performing this operation for about 30 minutes, the linear carbon atoms collide with the surface of the substrate 1, and the linear carbon atoms In step 3, the carbon atoms injected into the substrate 1 are covalently bonded.

  In addition, hexamethyldisiloxane is introduced for about 10 minutes from the start of this step. That is, hexamethyldisiloxane is introduced for 10 minutes after the start of this step from 10 minutes before the end of Step 3.

  And by the introduction of this hexamethyldisiloxane, a strong bond between the substrate and the carbon atom by the —C—Si—O— bond is performed.

  Step 4-2: Subsequently, as in Step 4-1 above, acetylene gas was introduced into the chamber 2 (vacuum degree 0.7 Pa) from the gas supply tank 15, and then a high-frequency pulse with a pulse width of 25 μs was applied. Immediately after application, a high voltage pulse with a pulse width of 5 μs is applied once to the substrate 1 at a voltage of 10 kV approximately 2000 times / second, and this operation is performed for 20 minutes. A DLC film is formed on the surface of the material 1.

  Step 5: Next, a gas in which 50% of acetylene and toluene are mixed is introduced from the gas supply tank 15 into the chamber 2 (vacuum degree: 0.9 Pa), and a high frequency pulse having a pulse width of 25 μs is applied to the substrate 1. After that, between immediately after the application and until 65 μs, a high voltage pulse with a pulse width of 5 μs is applied once to the substrate 1 at a voltage of 10 kV, about 4000 times / second, and this operation is performed for 3 hours. Thus, by applying a moderate ion bombardment to the carbon atoms constituting the DLC film to align the carbon atoms and rapidly increasing the thickness of the DLC film, the surface of the substrate 1 is finally reduced in residual stress. A thick (10 to 100 μm) DLC film is firmly formed.

  In each step in the present embodiment, the high voltage pulse is applied only once at a predetermined timing immediately after the application of the high frequency pulse. However, as shown in FIG. 4, the high voltage pulse may be applied a plurality of times. Further, the application of the high voltage pulse may be performed during the application, not immediately after the application of the high frequency pulse.

  〔Evaluation test〕

  Scratch test: A sample in which a DLC film was formed on the surface of a plate-like base material made of a zinc alloy in the same manner as in the above embodiment, at a scratch speed of 10 mm / min, a load of 100 N / min, and a tip radius of the diamond needle of 0.2 mm As a result, as shown in FIG. 5, the critical load Lc at which the acoustic emission signal increases was 10N. Although this numerical value itself is not high, when the surface of the sample after the scratch test was observed with a CCD camera, the DLC film on the surface of the sample was scraped without peeling off from the surface of the sample substrate. It was confirmed that the DLC film was firmly adhered to the substrate surface. Therefore, the reason why the measured critical load value was not high is considered to be a result of deformation of the substrate itself during the scratch test because the sample substrate was a soft zinc alloy.

    Film thickness test: A polyimide film tape (trade name: Kapton) was adhered to a part of the surface of a plate-shaped substrate made of a zinc alloy, and the tape was subjected to DLC film formation in the same manner as in the above embodiment. As shown in FIG. 6, a thick DLC film with a thickness of several μm was measured when the level difference between the part where the DLC film was deposited and the other part where the DLC film was formed was measured with a step gauge. It was done.

  From the results of the scratch test and the film pressure test, in the pulse plasma ion implantation process and the initial film formation stage in the above embodiment, ions are implanted into the substrate with high ion energy and at the interface between the substrate and the DLC film. In addition, a gradient layer of implanted atoms and carbon atoms constituting the DLC film is formed by heating accompanying ion collision. After the initial film-forming stage of the film-forming process, the heat generated by the impact of ion energy that is lower than before is obtained. It is considered that the high-speed film formation in which the residual stress was suppressed by the spike was performed, and the DLC film formation having a structure as shown in FIG. 7 was finally performed.

  Residual stress test: Sample in which a DLC film was formed using pulsed plasma of acetylene gas and toluene gas using a film forming apparatus similar to that of the above embodiment, with a strip-shaped substrate made of quartz glass supported by a holder. The residual stress was measured by the cantilever method.

  Specifically, as shown in FIG. 8, the residual stress was measured by bending the sample 21. In this case, the DLC film 22 on the surface of the sample 21 is deformed into a convex arc shape, and thus the compressive stress is measured. It will be.

  The result of the residual stress test is as shown in FIG. 9. The residual stress of the DLC film using toluene gas is hardly affected by the change in the set voltage of the high voltage pulse, and the residual stress value is approximately 0. It is recognized that the residual stress of the DLC film formation using acetylene gas decreases as the set voltage of the high voltage pulse is increased. When the set voltage is set to 15 kV, the residual stress is approximately 0. It decreased to about 2 GPa. This is because the residual stress of the DLC film obtained by the conventional chemical vapor deposition method (CVD) or physical vapor deposition method (PVD) is 10 GPa or more, and the residual stress according to the test result is 1/10 or less. It can be said.

  (Embodiment 2)

  In the present embodiment, a DLC film is formed on the surface of a base material made of iron-based metal such as high carbon steel or carburized steel, or copper, brass, magnesium alloy or the like.

  Step 1: First, after the chamber 2 is evacuated by the vacuum device 14, a mixed gas of argon and hydrogen is introduced into the chamber 2 from the gas supply tank 15.

  Thereafter, a high frequency pulse having a pulse width of 100 μs is applied to the substrate 1, and then a high voltage pulse having a pulse width of 10 μs is applied to the substrate 1 once at a voltage of 10 kv immediately after the application to 50 μs (FIG. 3). The surface of the substrate 1 was adjusted by repeating this operation for about 2000 times / second and performing this operation for about 30 minutes.

  Step 2 1: Next, tetraisopropoxy titanium was introduced into the chamber 2 from the gas supply tank 15 using methane gas as a carrier gas.

  Thereafter, a high frequency pulse having a pulse width of 30 μs is applied to the substrate 1, and then a high voltage pulse having a pulse width of 10 μs is applied to the substrate 1 once at a voltage of 15 kv immediately after the application to 40 μs (FIG. 3). (See) was repeated about 1000 times / second and this operation was performed for about 30 minutes.

  Step 2-2: Next, similarly to Step 2-1 above, tetraisopropoxytitanium was introduced from the gas supply tank 15 into the chamber 2 using methane gas as a carrier gas.

  Thereafter, a high frequency pulse having a pulse width of 30 μs is applied to the substrate 1, and then a high voltage pulse having a pulse width of 10 μs is applied to the substrate 1 once at a voltage of 10 kv immediately after the application to 100 μs (FIG. 3). (See) was repeated about 2000 times / second, and this operation was performed for about 50 minutes.

  Step 3 1: Next, a mixed gas of hexamethyldisiloxane and hydrogen was introduced into the chamber 2 from the gas supply tank 15.

  Thereafter, a high frequency pulse having a pulse width of 30 μs is applied to the substrate 1, and then a high voltage pulse having a pulse width of 3 μs is applied once to the substrate 1 at a voltage of 20 kv immediately after the application to 40 μs (FIG. 3). (See) was repeated about 1000 times / second and this operation was performed for about 30 minutes.

  Step 3-2: Next, a mixed gas of hexamethyldisiloxane, methane and acetylene was introduced into the chamber 2 from the gas supply tank 15.

  Thereafter, a high frequency pulse having a pulse width of 30 μs is applied to the substrate 1, and then a high voltage pulse having a pulse width of 10 μs is applied to the substrate 1 once at a voltage of 5 kv immediately after the application to 40 μs (FIG. 3). (See) was repeated about 2000 times / second, and this operation was performed for about 50 minutes.

  Step 4 1: In parallel with Step 3-2, a mixed gas of toluene, methane and acetylene was introduced into the chamber 2 from the gas supply tank 15.

    Thereafter, a high frequency pulse having a pulse width of 30 μs is applied to the substrate 1, and then a high voltage pulse having a pulse width of 10 μs is applied to the substrate 1 once at a voltage of 15 kv immediately after the application to 100 μs (FIG. 3). (See) was repeated about 4000 times / second, and this operation was performed for about 30 minutes.

  Step 4-2: Thereafter, the application voltage of the high voltage pulse was lowered to 10 kv, and the same operation as in Step 4-1 was performed for about 60 minutes.

  In each step in the present embodiment, the high voltage pulse is applied only once at a predetermined timing immediately after the application of the high frequency pulse. However, as shown in FIG. 4, the high voltage pulse may be applied a plurality of times. Further, the application of the high voltage pulse may be performed during the application, not immediately after the application of the high frequency pulse.

  Moreover, in this embodiment, the time of each step is arbitrarily changed, and each step may be performed independently in the chamber 2, or the preceding and following steps may be performed in parallel. is there. These correspond to the desired gradient structure of the finally obtained DLC film.

  According to this embodiment, as shown in FIG. 12, after the surface adjustment of the base material, titanium is first injected into the base material, and a titanium ceramic film is formed on the base material surface in an inclined manner, When silicon is injected, a silicon ceramic film is formed in an inclined shape, finally carbon is injected and a DLC film is formed in an inclined shape, and carbon exists in an inclined shape from the base material to the DLC film. is doing. Accordingly, since the DLC film as a whole has the above-described analog inclined structure, DLC film with high adhesion strength is finally formed on the substrate.

  In this embodiment, before the DLC film formation in Step 4, in Step 3, silicon implantation using hexamethyldisiloxane and film formation of the silicon ceramic film were performed. However, Step 3 is omitted and Step 2 is performed. Step 4 may be performed after this.

  Even in this case, as shown in FIG. 13, the elemental analysis in the depth direction was performed on the base material made of aluminum alloy. However, the shape in which carbon, oxygen, titanium, oxygen, etc. each support the above-described inclined structure. Distributed by.

  [Evaluation test]

  With respect to the present embodiment, as a result of conducting a scratch test to examine the adhesion strength of the DLC film-formed material based on copper and brass, the critical load Lc was 10N for copper and 12N for brass. Compared to DLC film formation on hard base materials such as cemented carbide, it is not numerically high, but since the base material is copper or brass, which is a soft metal, numerical values of sufficient critical load as adhesion strength It can be said that.

  Further, as a result of performing a film peeling test on a DLC film-formed product based on brass, as shown in FIG. 14, a DLC film-formed material obtained by directly forming a DLC film on a base material without using a titanium ceramic film. In this case, the DLC film could not follow the substrate from the central indentation to the periphery thereof, and peeling occurred in a wide range. On the other hand, in the present invention in which the DLC film is formed through the titanium ceramic film, as shown in FIG. 15, only the fine crack is generated at the periphery of the central indentation, and the DLC film itself is peeled off. It was confirmed that the DLC film was sufficiently adhered to the substrate.

It is a front view which shows an example of a DLC film-forming apparatus. It is a circuit diagram which shows an example of the superimposition apparatus in the film-forming apparatus of FIG. It is a chart which shows the application timing of high frequency electric power and a high voltage pulse. It is a chart which shows the other application timing of high frequency electric power and a high voltage pulse. It is a graph which shows the result of a scratch test. It is a graph which shows the result of a film thickness test. It is a figure which shows the DLC film-forming structure which abbreviate | omitted hydrogen. It is a front view which shows an example of a residual stress test. It is a graph which shows the result of a residual stress test. It is a front view which shows an example of the conventional DLC film-forming apparatus. It is a figure which shows the hollow cathode phenomenon in a base material. It is a figure which shows the inclined film-forming structure in the DLC film-forming material based on Embodiment 2. FIG. It is a graph which shows element distribution of the depth direction of the base material in a DLC film-forming thing. It is an enlarged photograph which shows the result of the film | membrane peeling test of the DLC film-forming thing which does not interpose a titanium ceramic film. It is an enlarged photograph which shows the result of the film | membrane peeling test of the DLC film-forming thing through a titanium ceramic film.

Explanation of symbols

1: Substrate 2: Chamber 7: Conductor 8: Feedthrough 9: Superimposing device 11: Power source for generating plasma 12: Power source for generating high voltage pulse 13: CPU
14: Vacuum device 15: Gas supply tank

Claims (21)

    A DLC film forming method for forming a DLC film on a surface of a substrate by a composite process using a pulse plasma and a combination of an ion implantation process and a film forming process using at least one hydrocarbon gas. The plasma generating high frequency power source and the high voltage pulse generating power source are connected to the base material in the chamber through a common feedthrough, and the high frequency pulse is applied to the base material from the plasma generating high frequency power source. A pulsed plasma is generated around the outer shape of the substrate, and a negative high-voltage pulse is applied to the substrate from the high-voltage pulse generating power source in the plasma or afterglow plasma at least once, and these high-frequency pulses are generated. Each of the above processes is performed by repeatedly applying a high voltage pulse and applying a high voltage pulse, and an ion is generated by the pulse plasma. The voltage of the high voltage pulse in the implantation process and the initial film formation stage is set higher than the voltage of the high voltage pulse in the film formation stage after the initial film formation stage, and the number of repetitions of the application of the high frequency pulse and the high voltage pulse is The method for forming a DLC film is characterized in that the number is increased in the film formation stage after the initial film formation stage.   The high frequency pulse width is a short pulse of 2 to 200 μs, the high voltage pulse width is a short pulse of 0.2 to 50 μs, and a high voltage pulse is applied during the application of the high frequency pulse or immediately after the application to 300 μs. The method for forming a DLC film according to claim 1, wherein:   A high-frequency pulse width is a short pulse of 5 to 20 μs, a high-voltage pulse width is a short pulse of 1 to 5 μs, and a high-voltage pulse is applied during or immediately after the application of the high-frequency pulse to 100 μs. The method for forming a DLC film according to claim 1, wherein:   The voltage of the high voltage pulse in the pulse plasma ion implantation process and the initial film formation stage is set to 20 kV, and the voltage in the subsequent film formation stage is set to 10 kV. The method for forming a DLC film according to any one of the above.   The DLC film composition according to any one of claims 1 to 4, wherein a silane coupling agent is added at least from the latter stage of the pulse plasma ion implantation process to the first stage of the initial film formation stage. Membrane method.   The silane coupling agent is hexamethyldisiloxane, the gas pressure in the chamber at the initial film formation stage in the film formation process is 0.3 to 0.5 Pa, and the gas pressure at the subsequent film formation stage is 0. 0. The method for forming a DLC film according to claim 5, wherein the pressure is 8 to 3 Pa.   A mixed gas containing argon and methane or hydrogen is used as the surface conditioning gas for the substrate, methane gas is used as the pulse plasma ion implantation gas, and acetylene, propane, butane, hexane, benzene, chlorobenzene is used as the film forming gas. The method for forming a DLC film according to claim 1, wherein at least one gas selected from the group consisting of toluene and toluene is used.   8. The method for forming a DLC film according to claim 1, wherein nitrogen gas is used before methane gas is used as ion implantation gas by pulse plasma.   A DLC film in which a DLC film is formed on the surface of a base material, and carbon atoms are injected from the surface of the base material to a predetermined depth, and one or more injected atoms of Si, Ti, and N And an inclined layer of the implanted atoms and the carbon atoms is formed at the interface between the substrate and the DLC film, and the implanted atoms in the substrate and the carbon atoms constituting the DLC film are covalently bonded. And a DLC film formed by aligning carbon atoms in the DLC film.   The DLC film-formed product according to claim 9, wherein the substrate is made of a zinc alloy, an aluminum alloy, a magnesium alloy, or iron.   A DLC film for forming a DLC film on the surface of a substrate via a titanium ceramic film by a composite process using a pulse plasma and a combination of an ion implantation process and a film forming process using at least one hydrocarbon gas. A film forming method, wherein a high frequency power source for plasma generation and a power source for high voltage pulse generation are connected to a base material in a chamber through a common feedthrough, and the high frequency power source for plasma generation is connected to the base material. A high frequency pulse is applied to generate a pulse plasma around the outer shape of the substrate, and a negative high voltage pulse is applied to the substrate at least once from the high voltage pulse generating power source in the plasma or afterglow plasma. In addition, by repeating the application of the high frequency pulse and the application of the high voltage pulse, the above processes are executed, and the previous process is performed. Using organotitanium alkoxide as a gas for forming a titanium ceramic film, injecting titanium into the substrate, forming a titanium ceramic film on the surface of the substrate, and then using a hydrocarbon-based gas as a gas for forming a DLC film A method for forming a DLC film, comprising: injecting carbon into the titanium ceramic film and then forming a DLC film on the titanium ceramic film.   A DLC film is formed on the substrate surface via a titanium ceramic film and a silicon ceramic film by a composite process using a pulse plasma and a combination of an ion implantation process and a film forming process using at least one hydrocarbon gas. A method for forming a DLC film, wherein a plasma generating high frequency power source and a high voltage pulse generating power source are connected to a substrate in a chamber through a common feedthrough, and the plasma generating high frequency power source is A high frequency pulse is applied to the base material to generate a pulse plasma around the outer shape of the base material, and a negative high voltage pulse is applied to the base material from the power source for generating a high voltage pulse in the plasma or afterglow plasma. By applying at least once and repeatedly applying these high frequency pulses and high voltage pulses, After performing the process and using organotitanium arcoside as the titanium ceramic film forming gas, injecting titanium into the base material, forming a titanium ceramic film on the surface of the base material, and then forming the silicon ceramic film A silane coupling agent is used as a working gas, silicon is injected into the titanium ceramic film, a silicon ceramic film is formed on the titanium ceramic film, and then a hydrocarbon-based gas is used as a DLC film forming gas. A method for forming a DLC film, comprising: injecting carbon into the silicon ceramic film and then forming a DLC film on the silicon ceramic film.   The voltage of the high voltage pulse in the ion implantation process by the pulse plasma and the initial film formation stage is set higher than the voltage of the high voltage pulse in the film formation stage after the initial film formation stage, and the application of the high frequency pulse and the high voltage pulse is performed. 13. The method for forming a DLC film according to claim 11 or 12, wherein the number of repetitions is increased in the film formation stage after the initial film formation stage.   The method for forming a DLC film according to claim 11, wherein nitrogen is implanted before titanium is implanted into the substrate.   The method for forming a DLC film according to claim 11, wherein the organotitanium alkoxide is tetraisopropoxytitanium.   The method for forming a DLC film according to any one of claims 12 to 15, wherein the silane coupling agent is tetramethylsilane or hexamethyldisiloxane.   A DLC film formed by forming a DLC film on a surface of a base material via a titanium ceramic film, wherein the titanium ceramic film is formed in an inclined shape from the base material to the surface of the base material. A DLC film-formed product in which a DLC film is formed in an inclined manner from the inside to the surface thereof, and carbon atoms are present in an inclined form from the base material to the DLC film. The DLC film-formed product according to claim 17, wherein the titanium ceramic film is TiOC _X.   A DLC film in which a DLC film is formed on a surface of a base material via a titanium ceramic film and a silicon ceramic film, and the titanium ceramic film is formed in an inclined shape from the base material to the surface of the base material, A silicon ceramic film is formed in an inclined shape from the titanium ceramic film to the surface thereof, a DLC film is formed in an inclined shape from the silicon ceramic film to the surface thereof, and carbon atoms are formed from the base material to the DLC film. Is a DLC film formed in an inclined shape. Titanium ceramic membrane is TiOC _X, wherein the silicon ceramic film is SiOC _X, claim 19 DLC film forming composition according.   The DLC film-formed product according to any one of claims 17 to 20, wherein the base material is copper, brass, high carbon steel, carburized steel, magnesium alloy or aluminum alloy.

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