JP5692497B2 - Surface processing method and surface processing apparatus - Google Patents

Description

The present invention relates to a surface processing method and a surface processing apparatus, and more specifically to a surface processing method for irradiating the surface of a workpiece with carbon cluster ions to ion-process the surface and a surface processing apparatus suitably used for the method. .

Conventionally, lathes, milling machines, polishing machines, hand polishing, and the like are used for surface finishing of products that require smooth surfaces such as various molds. However, this process is not only expensive, but there is a limit to improving the surface roughness. In particular, when a workpiece having an aspheric curved surface is polished by a human hand as a final process, the surface roughness is improved, but the shape accuracy of the aspheric surface is adversely affected. There's a problem. Further, hard materials such as cemented carbide and polycrystalline diamond (PCD) have a problem that it is extremely difficult to perform high-precision and precise surface processing by hand.

DLC (Diamond Like Carbon) coating is often applied to glass product dies and punch dies of press dies for the purpose of ensuring mirror surface. Such a coating wears with the use of a mold, but if this can be peeled off and re-coated, a significant reduction in mold cost can be expected. However, coatings such as DLC are coated on the mold surface via an intermediate layer such as SiC in order to improve the adhesion to the mold surface, and added functions (improvement of conductivity, self-lubricating properties). For example, because the DLC is doped with a hetero element such as nitrogen, silicon, or fluorine, it is not easy to remove the coating, and it is necessary to use plasma or the like. However, when the DLC coating or the intermediate layer is peeled off by plasma irradiation, the surface roughness of the mold surface is lowered, so that the mirror surface processing of the mold surface is required again. For this reason, recoating is not a practical option in consideration of cost and labor, and at present, a high-precision mold having a worn coating is remanufactured.

In view of the above situation, surface processing and fine processing of hard materials using an ion beam have been studied (see, for example, Non-Patent Document 1). According to this method, processing is possible regardless of the hardness of the material, so that it can be applied to hard materials such as cemented carbide and PCD.

As one of means for improving the surface roughness of the workpiece surface, there is known an ultra-precise polishing method in which the surface of the workpiece is irradiated with a gas cluster ion beam to smooth the surface (for example, patent document). 1). When the surface of the workpiece is irradiated with the gas cluster ion beam, the gas cluster ions are broken due to collision with the workpiece, and the cluster constituent atoms or molecules and the workpiece constituent atoms or molecules collide with each other. Activates the movement of horizontal atoms or molecules on the surface of objects. As a result of this movement, the protrusions on the workpiece surface are mainly scraped (lateral sputtering). Based on this principle, the workpiece surface can be smoothed at the atomic size level. Using this method, it is also possible to smooth the workpiece having a curved surface (see, for example, Patent Document 2).

Japanese Patent No. 3451140 JP 2007-32185 A

Hiroyuki Hosokawa, Tsuyoshi Nakajima, Yasushi Shimojima, Focused Ion Beam Microfabrication Characteristics of WC-Co Cemented Carbide, Powder and Powder Metallurgy, Japan Association of Powder and Powder Metallurgy, Volume 53 No. 2 (August 4, 2006) Sun), 187-191

However, in normal surface processing using a monoatomic ion beam, a phenomenon referred to as so-called selective sputtering due to the dependence of the sputtering rate on the atomic bonding force occurs, and the surface roughness after processing deteriorates. Since selective sputtering occurs also between a crystal and a grain boundary, a monoatomic ion beam has a problem that it cannot be applied to smoothing the surface of a material other than a single crystal.

Further, in the ultra-precision polishing method using the gas cluster ion beam described in Patent Documents 1 and 2, when smoothing a workpiece having a curved surface, the optimum setting for each surface In order to irradiate the gas cluster ion beam, a complicated control mechanism is required. Therefore, there is a problem that an expensive apparatus is required, a plurality of workpieces cannot be processed at a time, and a long time is required for processing.

This invention is made | formed in view of this situation, and it aims at providing the surface processing method and surface processing apparatus which can process the surface of a workpiece with high smoothness.

According to the first aspect of the present invention, the first step of introducing a gaseous carbon cluster ion source without using a carrier gas into a vacuum chamber in which a workpiece is accommodated, and the vacuum chamber A second step of generating a carbon cluster ion by applying a high-frequency voltage to the carbon cluster ion source introduced into the plasma, and a negative voltage applied to the electrode disposed in the vacuum chamber so as to hold the workpiece the applied irradiating the carbon cluster ions on the processed surface of the workpiece, solving the above problems by the working surface to provide a surface processing method characterized by a third step of ion machining To do.

After a plurality of carbon atoms are bonded by a covalent bond and carbon cluster ions (cations) having a structure such as a ring shape, a cage shape or a spherical shell shape are generated in a vacuum chamber containing a workpiece by a plasma method, When a negative voltage is applied to the workpiece, the surface of the workpiece can be irradiated with carbon cluster ions by electrostatic attraction. Also in this case, as in the case of the gas cluster ion beam, since lateral sputtering occurs on the surface of the workpiece, surface processing such as polishing can be performed with high smoothness. In addition, since irradiation of carbon cluster ions onto the surface of the workpiece is driven by electrostatic attraction, complicated condition control is not required and a plurality of workpieces can be processed simultaneously.
Furthermore, by introducing the carbon cluster ion source into the vacuum chamber without using the carrier gas, no monoatomic ions derived from the carrier gas are generated. For this reason, selective sputtering does not occur on the surface of the workpiece, and a reduction in surface roughness due to processing can be suppressed.

In the surface processing method according to the first aspect of the present invention, be pre SL value of the surface roughness of the processing surface after ion processing is less than or equal to the surface roughness values of the processed surface before the ion processing preferable.

In the surface processing method according to the first aspect of the present invention, the carbon cluster ion source is selected from the group consisting of perfluorocycloalkanes having 4 to 12 carbon atoms, fullerenes having 20 to 120 carbon atoms, and fullerene derivatives. One or more compounds may be used.

In the surface processing method according to the first aspect of the present invention, the carbon cluster ion source is preferably one or more compounds selected from the group consisting of fullerenes having 60 to 120 carbon atoms and fullerene derivatives, In this case, in the first step, the solid carbon cluster ion source is preferably vaporized by heating and sublimating under reduced pressure.
Fullerenes and fullerene derivatives having a carbon number within the above range can be sublimated without causing thermal decomposition, and can generate carbon cluster ions with high yield by applying a high-frequency voltage. Therefore, it can be particularly suitably used as a carbon cluster ion source.

According to a second aspect of the present invention, there is provided a vacuum tank connected to a decompression device, a heat-resistant container having one end opened toward the vacuum tank, and solid or liquid carbon stored in the container A carbon cluster ion source supply means comprising heating means for heating and vaporizing the cluster ion source, an electrode disposed in the vacuum chamber so as to hold a workpiece, and the electrode connected to the electrode A first power source for applying a negative voltage to the workpiece held on the electrode, and the workpiece held on the electrode, and disposed in the vacuum chamber so as to face the electrode across the workpiece. A high-frequency electrode, and a second power source connected to the high-frequency electrode for generating a carbon cluster ion by applying a high-frequency voltage to a carbon cluster ion source introduced into the vacuum chamber to generate plasma. Features It is intended to solve the above problems by providing a surface processing device.
By heating and vaporizing a solid or liquid carbon cluster ion source under reduced pressure, it can be introduced into the vacuum chamber without using a carrier gas, so that selective sputtering caused by monoatomic ions derived from the carrier gas can be performed. Generation can be suppressed. Therefore, the surface processing of the workpiece can be performed with high smoothness. Moreover, since a complicated control mechanism is not required, the surface processing apparatus according to this aspect can be manufactured at low cost and has excellent reliability.

In the surface processing apparatus according to the second aspect of the present invention, it is preferable that the carbon cluster ion source supply means is provided in the vacuum chamber.
Loss when introducing the carbon cluster ion source into the vacuum chamber can be reduced, and the utilization efficiency of the carbon cluster ion source can be improved.

ADVANTAGE OF THE INVENTION According to this invention, the surface processing method and surface processing apparatus which can process the surface of a workpiece with high smoothness can be provided. According to the surface processing method of the present invention, surface processing can be performed easily and in a short time without using a complicated control mechanism, and a plurality of workpieces can be processed simultaneously. A decrease in surface roughness due to sputtering can be suppressed. Furthermore, when the workpiece has electrical conductivity, it is possible to perform surface processing on a workpiece having a complicated shape including a curved surface. In addition, with respect to inorganic thin films such as DLC coated on the mold surface through an intermediate layer such as SiC or DLC doped with a hetero element, the surface roughness of the processed surface of the mold as a base material should be reduced. Since it is possible to remove the worn inorganic thin film from the high-precision mold coated with the hard inorganic thin film without damaging the surface roughness and shape of the processed surface, it is possible to remove these by recoating. Mold regeneration is possible.

It is explanatory drawing of the surface processing apparatus which concerns on the 1st Embodiment of this invention. It is the ultraviolet visible emission spectrum of the plasma of fullerene generated by high frequency discharge. It is the scanning electron microscope (SEM) photograph and roughness curve of the surface of the polycrystalline diamond (PCD) (plate shape) before and after surface processing by the carbon cluster ion generated from the plasma of fullerene. It is a scanning electron microscope (SEM) photograph of the surface of polycrystalline diamond (PCD) (tool shape) before and after surface processing by carbon cluster ions generated from fullerene plasma. It is a scanning electron microscope (SEM) photograph and roughness curve of the surface of SUS440C (flat plate) before and after surface processing by carbon cluster ions generated from fullerene plasma. It is a scanning electron microscope (SEM) photograph and roughness curve of a polycrystalline diamond (PCD) (plate-like) surface before and after surface processing by carbon cluster ions generated from perfluorocyclobutane plasma. It is a depth curve which shows the processing depth with respect to the non-irradiation part of the carbon cluster ion irradiation part produced | generated from the plasma of perfluorocyclobutane in the cemented carbide plate which gave DLC coating (DLC80nm + SiC intermediate | middle layer 20nm). It is a roughness curve which shows the comparison of the surface roughness of the carbon cluster ion irradiation part and non-irradiation part which were generated from the plasma of perfluorocyclobutane in the cemented carbide plate which gave DLC coating (DLC80nm + SiC intermediate layer 20nm). It is a roughness curve which shows the comparison of the surface roughness of the argon plasma irradiation part and the non-irradiation part in the cemented carbide plate which has not performed DLC coating.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention. As shown in FIG. 1, a surface processing apparatus 10 according to the first embodiment of the present invention (hereinafter may be abbreviated as “processing apparatus”) is related to a second embodiment of the present invention. It is an apparatus that can be suitably used for carrying out the surface processing method, a vacuum tank 12 connected to a vacuum pump (an example of a decompression apparatus) 11, a heat-resistant container 21 having one end opened toward the vacuum tank 12, Fullerene sublimation comprising a heater (an example of a heating means) 22 for heating and vaporizing a fullerene (an example of a solid or liquid carbon cluster ion source) 31 stored inside by heating the container 21 An apparatus (an example of a carbon cluster ion source supply unit) 13, an electrode 14 disposed in the vacuum chamber 12 so as to hold the workpiece 32, and a workpiece 32 connected to the electrode 14 and held by the electrode 14 Negative to A high-frequency pulse power source (an example of a first power source) 15 for applying pressure and a high frequency wave disposed in the vacuum chamber 12 so as to face the electrode 14 with a workpiece 32 held on the electrode 14 interposed therebetween. Carbon cluster ions (an example of a carbon cluster ion source) generated from fullerene plasma by applying high frequency voltage to the electrode 16 and gaseous fullerene connected to the high frequency electrode 16 and introduced into the vacuum chamber 12 to generate plasma. Hereinafter, it may be abbreviated as “fullerene ion”.) A high-frequency power source (an example of a second power source) 17 for generating 33 is provided.

Any known pump can be used as the vacuum pump 11 according to the desired degree of vacuum. For example, when a vacuum of about 10 ⁻¹ Pa is sufficient, an oil rotary pump, and when a vacuum of about 10 ⁻³ to 10 ⁻⁷ Pa is required, an oil diffusion pump or a turbo molecular pump, 10 ⁻⁸ Pa When a degree of vacuum is required, an ion pump is used. A higher degree of vacuum can reduce the effect of selective sputtering due to monoatomic ions, but an expensive pump is required, which increases the cost of the apparatus. Therefore, the pressure in the vacuum chamber 12 is set to about 1 × 10 ⁻³ Pa in view of cost and the like.

Although FIG. 1 shows an example in which a pressure adjusting valve 12a in the vacuum chamber 12 is provided between the two, a vacuum gauge, a leak valve or the like (not shown) may be provided. Good. Moreover, in order to observe the structure of fullerene ions 33 generated inside the vacuum chamber 12, a measuring means for carbon cluster ions such as a spectrophotometer or a time-of-flight mass spectrometer (TOF-MS) may be provided. .

The form of the vacuum chamber 12 is not particularly limited, but specific examples include a box type, a distribution pipe type, and a bell jar type. There is no restriction | limiting in particular also about the magnitude | size of the vacuum chamber 12, According to the magnitude | size and shape of the to-be-processed object 32, the thing of a suitable magnitude | size can be selected suitably.

Inside the vacuum chamber 12, a fullerene sublimation device 13 for introducing gaseous fullerene into the vacuum chamber 12 is provided. The fullerene sublimation apparatus 13 includes a container 21 having one end opened in the vacuum chamber 12 and a heater 22 for heating the container and sublimating the solid fullerene 31 stored therein. There is no restriction | limiting in particular in the shape and magnitude | size of the container 21, It determines suitably according to the quantity etc. of the fullerene 31 stored inside. The material of the container 21 can be appropriately selected from any material having heat resistance that does not cause deformation or decomposition at the heating temperature of the heater 22. Specific examples thereof include ceramics such as glass, ceramics, porcelain, and copper. , Metals such as aluminum and stainless steel, and graphite.

In order to supply current to the heater 22, a power source (not shown) different from the high voltage pulse power source 15 and the high frequency electrode 16 is connected to the heater 22. The heating temperature of the heater 22 is appropriately determined according to the degree of vacuum in the vacuum chamber 12 and the type of fullerene used as the carbon cluster ion source, but is set to a temperature lower than the thermal decomposition temperature of the fullerene used. . For example, when the degree of vacuum in the vacuum chamber 12 is 0.1 Pa, the heating temperature of the heater 22 is set to 200 to 600 ° C.

The fullerene sublimation apparatus 13 may be provided inside the vacuum chamber 12 as in the present embodiment, but the opening on one end side of the container 21 is open toward the inside of the vacuum chamber 12, and the carrier As long as the sublimated fullerene can be introduced into the vacuum chamber 12 without using a gas, it may be provided outside the vacuum chamber 12.

The shape of the electrode 14 may be a plate-like shape on which the workpiece 32 can be placed as shown in FIG. 1, but the electrode 14 can be appropriately held according to the shape of the workpiece 32. It may have any shape and structure. The size 14 of the electrode is appropriately adjusted according to the size and number of workpieces 32 to be held. As the material of the electrode 14, any material is appropriately selected as long as it has sufficient conductivity to apply a high voltage to the workpiece 32 and sufficient strength to hold the workpiece 32. Can be used.

As the high-voltage pulse power supply 15, a voltage necessary for irradiating the surface of the workpiece 32 with the fullerene ions 33 at a sufficient speed (the fullerene ions 33 are positive ions, which are accelerated by electrostatic attraction, A negative voltage must be applied to irradiate the surface of the workpiece 32. The same applies to other carbon cluster ions.) As long as a current can be applied, an arbitrary voltage and capacity are appropriately selected. Can be used. The applied voltage, current, pulse width, and duty cycle are appropriately selected according to the type of fullerene used, the type, shape and size of the workpiece 32, the processing depth, etc., and are therefore difficult to determine uniquely. However, for example, the voltage is set to a value of about −5 to −12 kV, a frequency of 1 kHz, and a pulse width of about 1 μs.

Examples of the shape of the high-frequency electrode 16 include a parallel flat plate type, a coaxial cylindrical type, a curved opposed plate type such as a cylinder and a sphere, a hyperboloid opposed flat plate type, and a plurality of fine wire opposed flat plate types. As a material of the high-frequency electrode 16, any material having conductivity with respect to a high-frequency voltage can be appropriately selected and used.

As the high-frequency power source 17, any known type can be used, and specific examples include a capacitive coupling type, an induction type using an external electrode, and the like. The output of the high-frequency power source 17 can continue a stable glow discharge according to the material and size of the workpiece 32, the type of carbon cluster ion source used, the capacity and pressure of the vacuum chamber 12, and the arc discharge. Although it adjusts suitably within the range which does not raise | generate, it is 10-250W, for example. The frequency of the high-frequency power supply 17 is also determined as in the case of the output, but the frequency widely used in the EN (European) standard is assigned to industrial, scientific and medical (ISM). Which is 13.56 MHz.
In addition, although it is possible to generate plasma also by applying a direct current, since the discharge start voltage can be lowered by using a high frequency voltage, a high frequency voltage is usually used.

Next, a surface processing method according to the second embodiment of the present invention will be described. Here, as an example, the case where the surface processing apparatus 10 according to the first embodiment of the present invention is used will be described.
The surface processing method includes a first step of introducing gaseous fullerene (an example of a carbon cluster ion source) 31 into the vacuum chamber 12 in which the workpiece 32 is accommodated without using a carrier gas, A second step of generating fullerene ions (an example of carbon cluster ions) by applying a high-frequency voltage to fullerene introduced in the step, and generating a fullerene ion (an example of carbon cluster ions ) . A third step of irradiating ions and ion-processing the surface .

The material of the workpiece 32 is not particularly limited, and the surface processing method according to the present embodiment can be applied to the surface processing of a workpiece made of any material regardless of the hardness, the presence or absence of electrical conductivity, and the like. Specific examples of the material of the workpiece 32 include organic substances such as natural and synthetic resins, and inorganic substances such as glass, ceramics, semiconductor materials, and metals.

When the workpiece 32 is an insulator, the incident direction of the fullerene ions 31 to the surface is perpendicular to the surface of the electrode 14. Therefore, in order to perform uniform surface processing, the shape of the workpiece 32 Is limited to a flat plate. On the other hand, in the case of the workpiece 32 made of a conductive material, the fullerene ions 33 are always incident from the vertical direction of the surface, so that highly uniform surface processing can be performed regardless of the shape. An example of the workpiece 32 to which the surface processing method according to the present embodiment is particularly preferably applied is polycrystalline diamond (PCD). PCD is obtained by sintering fine granular diamond using cobalt as a sintering aid. It has electrical conductivity and is used as a tool for fine processing of hard materials such as glass. The surface processing is difficult with the conventional method. This method of irradiating the surface with carbon cluster ions can perform surface processing with high smoothness regardless of the hardness of the workpiece.
Also, inorganic from glass molds and press molds in which a hard inorganic film is formed directly or via an intermediate layer on the processing surface (cavity or core) of the mold, which is a conductive substrate. The surface processing method according to the present embodiment is preferably applied to the removal of the film, or both the inorganic film and the intermediate layer. The kind of the inorganic film is not particularly limited, and examples thereof include DLC commonly used for coating on a mold surface, a sliding member, etc., and heteroatom doped DLC such as nitrogen, silicon and fluorine. The inorganic film may be directly bonded to the substrate surface, or may be bonded to the substrate surface through an intermediate layer such as SiC.
The shape of the workpiece 32 is not particularly limited, and surface processing can be performed on the workpiece 32 having an arbitrary shape without using a complicated control mechanism.

In the present embodiment, fullerene 31 is used as the carbon cluster ion source. “Fullerene” refers to a spherical shell-like or substantially spherical shell-like molecule composed of only carbon and having a hollow closed shell structure, and the number of carbon atoms forming the closed shell structure is usually an even number of 60 to 120. Specific examples of fullerenes include C ₆₀ , C ₇₀ , C ₇₆ , C ₇₈ , C ₈₂ , C ₈₄ , C ₉₀ , C ₉₄ , C ₉₆ , and spherical shells or substantially spheres having more carbon than these. Mention may be made of shell-like carbon molecules. In the spherical shell-like or substantially spherical shell-like molecule and the spherical shell-like structure or the substantially spherical shell-like structure, a part of carbon constituting this may be deficient.

Alternatively, a fullerene derivative may be used as the carbon cluster ion source. Here, the “fullerene derivative” is a general term for compounds or compositions in which an organic or inorganic atomic group is bonded to a carbon atom of fullerene. For example, in addition to those having a structure in which a predetermined substituent is added to the fullerene skeleton, those including a fullerene metal complex containing a metal or a molecule inside are meant broadly.

Specifically, hydrogenated fullerene, oxidized fullerene, hydroxylated fullerene, aminated fullerene, sulfurized fullerene, halogenated (F, Cl, Br, I) fullerene, fulleroid, methanofullerene, pyrrolidinofullerene, alkylated fullerenes, Examples include arylated fullerenes. In these fullerene derivatives, the number of substituents added to the fullerene skeleton may be plural, or two or more different types of substituents may be added. In addition, a fullerene derivative may be used individually by 1 type, or what mixed multiple types in arbitrary ratios may be used for it.

Among these fullerenes and fullerene derivatives, C ₆₀ and C ₇₀ and their derivatives are preferable because they are the main products in the production of fullerenes, and mixtures thereof, derivatives thereof, C ₆₀ or derivatives thereof are more preferable. preferable. In other words, preferably has a fullerene skeleton is a _{C 60} or _{C 70,} a mixture of those fullerene skeleton is _{C 60} and _{C 70,} or it is more preferable one of a _{C 60} and _{C 70.}

Alternatively, examples of carbon cluster ion sources other than fullerene and fullerene derivatives include perfluorocycloalkanes having 4 to 12 carbon atoms, and specific examples include perfluorocyclobutane, perfluorocyclopentane, perfluorocyclohexane, perfluoro. And cyclooctane. Among these perfluorocycloalkanes, those that are liquid at room temperature can be introduced into the vacuum chamber 12 using the same supply means as the fullerene sublimation apparatus 13 described above. Alternatively, the gas may be introduced directly into the vacuum chamber 12 as a gas.

Application of a negative voltage to the workpiece 32 for irradiation of fullerene ions may be performed continuously, but in order to suppress an excessive increase in surface temperature, a negative voltage is applied for a predetermined time, and then cooling is performed. Therefore, a cycle of setting a predetermined waiting time may be repeated a predetermined number of times.

The surface roughness value of the processed surface after ion processing by irradiation of fullerene ions is preferably not more than the surface roughness value of the processed surface before ion processing. In particular, the present embodiment is used for removing inorganic coatings from glass molds and press dies in which a hard inorganic coating is formed on the processed surface directly or through an intermediate layer, or both inorganic coatings and intermediate layers. In the case of applying the surface processing method according to the embodiment, when ion processing that satisfies the above conditions becomes possible, it is possible to reuse an expensive mold by forming an inorganic film again. This can greatly contribute to a reduction in cost and, in turn, a reduction in manufacturing cost of precision processed parts. The surface roughness of the processed surface can be measured using any known means and apparatus such as a stylus type surface roughness measuring instrument, a contact type or a non-contact type three-dimensional measuring instrument.

Next, examples carried out for confirming the effects of the present invention will be described.
Example 1 Surface Processing of Polycrystalline Diamond (PCD) (1) Apparatus and Conditions Using a surface processing apparatus having the configuration shown in FIG. 1, a workpiece made of polycrystalline diamond (PCD) having conductivity is formed. Surface processing was performed. The surface processing procedure is as follows.
The inside of the vacuum chamber was evacuated with a vacuum pump until the pressure reached 1 × 10 ⁻³ Pa or less. After reaching a predetermined pressure, the fullerene contained in a graphite container was heated with a halogen lamp (600 ° C.) to be sublimated. The fullerene pressure was adjusted by the heating temperature of the fullerene by the halogen lamp and the valve opening of the exhaust system. As the fullerene, nanom mix (registered trademark) manufactured by Frontier Carbon Co., Ltd. (C ₆₀ : about 60%, C ₇₀ : about 25%, other higher-order fullerene: about 15%) was used. After adjusting the pressure in the vacuum chamber to a predetermined value, a high-frequency power source (13.56 MHz) was operated to apply a high-frequency voltage to the high-frequency electrode, and the fullerene was turned into plasma. Next, in a state where fullerene plasma is generated, a negative high voltage pulse power supply (manufactured by Heiwa Power Supply Co., Ltd.) is operated, and a pulsed negative voltage (−5 kV, frequency 1 kHz, pulse width 1 μs) is applied to the workpiece. The surface was smoothed by applying fullerene ions to the surface.

FIG. 2 shows an ultraviolet-visible emission spectrum of fullerene plasma generated by high-frequency discharge (fullerene pressure 15 Pa, high-frequency power output 300 W). Literature values of emission wavelength from C ₂ (516.52 nm, 558.55 nm, 605.97 nm, 659.92 nm) (V. Foltin et al., Chem. Phys. Lett., 289, pp.181-188 (1998) A peak consistent with)) was confirmed. Since fullerene is easily decomposed (C ₆₀ → C ₅₈ + C ₂ ) when subjected to electron impact, such a peak is considered to have appeared.

(2) Surface processing of flat-plate PCD PCD is TDC-GM (diamond average particle size: 3 μm, mirror finish) manufactured by Tomei Dia Co., Ltd., ultrasonically cleaned in acetone, and then placed on the electrode And installed in a vacuum chamber. The fullerene charged in the sublimation apparatus is heated (600 ° C.) to be sublimated, and the high-frequency discharge (fullerene (“C ₆₀ ” is shown in FIG. 3 showing the result of this example. The same applies to FIG. 4). There was a pressure of 0.09 Pa and an output of 25 W) to generate plasma. By applying a pulsed negative voltage to the electrode (20 minutes) and irradiating the surface with fullerene ions (masking other than the irradiated part so that only a predetermined part is irradiated), the surface of the PCD Processing was performed. The roughness and depth of the part processed with fullerene ions were measured with a contact-type surface shape measuring instrument (Form Talysurf S5 manufactured by Taylor Hobson Co., Ltd.). The processing depth was determined from the level difference from the masked part. Further, in order to observe the surface state, the surface before and after the surface processing was observed with a scanning electron microscope (SEM).

The results are shown in FIG. Since surface processing was performed on a surface that had been mirror-finished in advance, no significant change was observed in the surface roughness before and after processing, but the occurrence of unevenness due to selective sputtering was not observed, and a uniform processing depth (60 nm) ) Shows that the processing was done. Moreover, it was confirmed from the SEM photographs of the surface before and after the processing that fine scratches observed on the surface before the processing disappeared by the surface processing.

(3) Surface processing of tool-shaped PCD The PCD was processed into a tool shape using a round bar made of the same material PCD as in (2) above. Processing into the tool shape was performed in the order of roughing by laser, intermediate finishing by electric discharge machining, and finishing by grinding. The shape of the tip after processing is shown in the SEM photograph at the bottom of FIG. Note that the radius of curvature of the tip is 50 μm. In order to avoid the accumulation of heat at the processing site, the pulsed negative voltage was applied to the surface of the tip portion of the PCD obtained in this manner except that it was applied for 5 minutes and cooled for 4 minutes for 4 cycles. Surface processing was performed under the same conditions as in (2).

The results are shown in FIG. Roughness could not be measured because the shape was fine, but the occurrence of irregularities and defects due to selective sputtering was not observed, and the processing depth was (2) from the net application time of the negative voltage. As in the case, it is considered to be about 60 μm.) It can be seen that the processing has been performed.
From the results of (2) and (3) above, it was confirmed that in the case of PCD having conductivity, a uniform and highly smooth surface processing is possible regardless of the shape.

Example 2: Surface processing of flat SUS440C Using SUS440C (Elmax), which is martensitic stainless steel processed into a flat plate, as a workpiece, fullerene pressure of 0.3 Pa, application of pulsed negative voltage Surface processing was performed under the same conditions as (2) of Example 1 except that the time was 60 minutes.

The results are shown in FIG. The surface roughness after surface processing (6.5 nm) is improved from that before surface processing (12.1 nm), and the occurrence of irregularities due to selective sputtering is not observed, and the uniform processing depth (50 nm). It can be seen that the processing was done. Moreover, it was confirmed from the SEM photographs of the surface before and after the processing that fine scratches observed on the surface before the processing disappeared by the surface processing.

Example 3: Surface processing of flat plate PCD by carbon cluster ions generated from plasma of perfluorocyclobutane Perfluorocyclobutane was used as a carbon cluster ion source, and the same flat plate as used in (2) of Example 1 PCD surface processing was performed. The PCD was ultrasonically cleaned in acetone and then placed in a vacuum chamber in a state of being placed on the electrode. Since perfluorocyclobutane is a gas, it was introduced into a previously evacuated vacuum chamber without using a sublimation apparatus and a carrier gas. After reaching a predetermined pressure (0.1 Pa), high frequency discharge (output 25 W) was performed to generate plasma. By applying a pulsed negative voltage to the electrode (25 minutes) and irradiating the surface with carbon cluster ions (masking other than the irradiated part so that only a predetermined part is irradiated), the PCD Surface processing was performed.

The results are shown in FIG. Since surface processing was performed on a surface that had been mirror-finished in advance, no significant change was observed in the surface roughness before and after processing, but the occurrence of unevenness due to selective sputtering was not observed, and a uniform processing depth (50 nm ) Shows that the processing was done. Moreover, it was confirmed from the SEM photographs of the surface before and after the processing that fine scratches observed on the surface before the processing disappeared by the surface processing.

Example 4: Surface processing of cemented carbide plate coated with DLC coating (DLC 80 nm + SiC intermediate layer 20 nm) with carbon cluster ions generated from perfluorocyclobutane plasma Using perfluorocyclobutane as a carbon cluster ion source, DLC coating (DLC 80 nm + SiC Surface processing of the cemented carbide plate with the intermediate layer 20 nm) was performed. The cemented carbide plate coated with DLC was ultrasonically cleaned in acetone, and then placed in a vacuum chamber while being placed on the electrode. Since perfluorocyclobutane is a gas, it was introduced into a previously evacuated vacuum chamber without using a sublimation apparatus and a carrier gas. After reaching a predetermined pressure (1.1 Pa), high frequency discharge (output 100 W) was performed to generate plasma. A negative pulse voltage is applied to the electrode (5 kV, frequency 1 kHz, pulse width 10 μs, 1 hour), and the surface is irradiated with carbon cluster ions (other than the irradiated part is masked so that only a predetermined part is irradiated) The depth and surface roughness of the irradiated part and the non-irradiated part were measured. The results are shown in FIG. It can be seen that the surface processing proceeds from the surface of the non-irradiated part to a depth of about 150 nm by irradiation with argon plasma.

The measurement result of the surface roughness of an irradiated part and a non-irradiated part is shown in FIG. When surface processing is advanced from the surface of the non-irradiated part to a depth of about 150 nm, the surface roughness of the irradiated part and the non-irradiated part is 5.8 nm and 5.7 nm, respectively. It was confirmed that surface processing (removal of DLC coating) can be performed with almost no change in roughness. Even when the irradiation time was increased and the processing depth was increased, no increase in surface roughness was observed.

Comparative Example: Argon plasma (generated under the same conditions as in Example 4 except that argon was used as the plasma source instead of perfluorocyclobutane) was used for comparison of surface processing of the cemented carbide plate with argon plasma. FIG. 9 shows the measurement results of the surface roughness of the irradiated part and the non-irradiated part when the surface of the cemented carbide plate (without DLC coating) is irradiated. The surface roughness of the irradiated part and the non-irradiated part when processing is carried out to a depth of about 50 nm from the surface of the non-irradiated part is 5.9 nm for the former and 9.9 nm for the former. It was confirmed that the surface roughness increased by the irradiation of. When the irradiation time of argon plasma was increased and the processing depth was increased, the surface roughness further increased.

DESCRIPTION OF SYMBOLS 10 Surface processing apparatus 11 Vacuum pump 12 Vacuum tank 12a Valve 13 Fullerene sublimation apparatus 14 Electrode 15 High voltage pulse power supply 16 High frequency electrode 17 High frequency power supply 21 Container 22 Heater 31 Fullerene 32 Workpiece 33 Fullerene ion

Claims (7)

A first step of introducing a gaseous carbon cluster ion source without using a carrier gas into a vacuum chamber in which a workpiece is accommodated;
A second step of generating a carbon cluster ion by applying a high frequency voltage to the carbon cluster ion source introduced into the vacuum chamber to form a plasma;
The third step of said applying a negative voltage to the electrode disposed retainably the vacuum chamber a workpiece by irradiating the carbon cluster ions on the processed surface of the workpiece, ion machining the working surface And a surface processing method. The value of the surface roughness of the processing surface after ion machining, surface machining method according to claim 1, wherein said at most the surface roughness values of the processed surface before the ion processing. The carbon cluster ion source is one or a plurality of compounds selected from the group consisting of perfluorocycloalkanes having 4 to 12 carbon atoms, and fullerenes and fullerene derivatives having 20 to 120 carbon atoms. The surface processing method of Claim 1 or 2 . 4. The surface processing method according to claim 3, wherein the carbon cluster ion source is one or a plurality of compounds selected from the group consisting of fullerenes having 60 to 120 carbon atoms and fullerene derivatives. 5. The surface processing method according to claim 4 , wherein in the first step, the solid carbon cluster ion source is vaporized by heating and sublimating under reduced pressure. A vacuum chamber connected to a decompressor;
Carbon cluster ions comprising a heat-resistant container having one end opened toward the vacuum chamber, and heating means for heating and vaporizing the solid or liquid carbon cluster ion source stored in the container Source supply means;
An electrode arranged in the vacuum chamber so as to hold a workpiece;
A first power source connected to the electrode and for applying a negative voltage to the workpiece held by the electrode;
A high-frequency electrode disposed in the vacuum chamber so as to face the electrode across the workpiece held on the electrode;
A surface connected to the high-frequency electrode and having a second power source for generating a carbon cluster ion by applying a high-frequency voltage to a carbon cluster ion source introduced into the vacuum chamber to form a plasma. Processing equipment. The surface processing apparatus according to claim 6, wherein the carbon cluster ion source supply means is provided in the vacuum chamber.

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