JP2020132466A - Hydrogen-containing carbon film - Google Patents

Abstract

To provide a carbon protective film of a cutting tool for a difficult-to-cut material in which a processing surface is high heat-resistant and has high quality, and a protective film or a self-supporting film of an article having high heat resistance.SOLUTION: A hydrogen-containing carbon film having an initiation temperature of hydrogen gas desorption when heated in vacuum of 800°C or higher. Since the present carbon film is, due to containment of hydrogen, while being provided with low friction, low aggression and flatness, and, due to high heat resistance, can maintain relatively high hardness difficult to cause graphitization or softening accompanying desorption of hydrogen gas even when a cutting position becomes locally high temperature, when used in a cutting tool, in particular, a protective film of a cutting tool covered with a diamond film, a high quality processed surface having less burr can be realized even to a difficult-to-cut composite material such as CFRP. The present carbon film can be preferably used also in a high heat resistant release film covering a surface of a mold such as molding mold of lens, and a high heat resistant self-supporting film separated from a base material.SELECTED DRAWING: Figure 2

Description

The present invention relates to a carbon film substantially containing hydrogen, and more particularly to a carbon film having a high hydrogen desorption temperature during heating.

A diamond-like carbon (DLC) film, also called an amorphous carbon film, has properties and physical properties similar to those of diamond or graphite, but is amorphous (amorphous) rather than crystalline, and is usually on the surface of some object. It is formed in a membranous state. The DLC film is widely applied as a protective film for tools, molds, and the like. The DLC film is roughly divided into a pure carbon film composed of only carbon and an impurity-containing carbon film containing other elements such as hydrogen. A carbon film that does not contain hydrogen is called a hydrogen-free DLC film, but the name "hydrogen-free DLC film" is usually used to mean a pure carbon film that does not contain other elements other than hydrogen. Further, the carbon film containing hydrogen is called a hydrogen-containing DLC film. In the present specification, unless otherwise specified, the name "carbon film" shall mean a DLC film (amorphous carbon film).

Hydrogen-free DLC film, classified to the sp ³ carbon rich with hybrid orbital component tetrahedral amorphous carbon (ta-C), amorphous carbon rich carbon having sp ² hybrid orbital component and (a-C) Will be done. The hardness, film density, and heat resistance of ta-C are higher in ta-C, and have physical properties closer to those of diamond. In addition, a-C shows physical properties closer to those of graphite. The hardness (nanoindentation hardness) is about 40 to 80 GPa for general ta-C and about 20 GPa for general a-C. Comparing the physical properties of the hydrogen-free DLC film and the hydrogen-containing DLC film, the hydrogen-containing DLC film tends to show smaller values in all of hardness, film density, heat resistance, and refractive index. In other words, the DLC film becomes soft by containing hydrogen, the film density and the refractive index decrease, and generally the heat resistance also decreases. Among the hydrogen-containing DLC films, the carbon-rich one having the sp ³ hybrid orbital component is hydrogen-containing tetrahedral amorphous carbon (ta-C: H), and the carbon-rich one having the sp ² hybrid orbital component is hydrogen-containing. It is called amorphous carbon (a-C: H). The carbon film according to the present invention generally has a composition near the boundary between ta-C: H and a-C: H, and spans both regions.

Carbon Fiber Reinforced Plastics (CFRP) is a composite material composed of a hard material such as carbon fiber and a soft material having low thermal conductivity such as resin. When cutting using such a composite material as a work material, the cutting location may become locally hot. Therefore, conventionally, the surface of a base material such as WC-based cemented carbide is heat-resistant. Cutting tools coated with a high hydrogen-free carbon film have been used. This is because a normal hydrogen-containing carbon film cannot sufficiently function as a protective film because hydrogen and the like are desorbed and graphitized at a locally high temperature and the film is softened. is there. However, in order to form a high-quality machined surface with less burrs, it is difficult to discard the hydrogen-containing carbon film, which has excellent low friction resistance, abrasion resistance, and low aggression against the material to be cut. The present inventor has recently found the composition, production method, and film forming conditions of a hydrogen-containing carbon film in which desorption of hydrogen occurs at 800 ° C. or higher. Since the hydrogen-containing carbon film according to the present invention has sufficiently high heat resistance, it can be applied as a protective film for a cutting tool for processing a work material such as CFRP with high quality. I found. Further, the present inventor further improves the quality of the machined surface by further coating the surface of the cutting tool, which is formed by coating the surface of the base material with a diamond film made of polycrystalline diamond, with the hydrogen-containing carbon film according to the present invention. I found out to do.

Japanese Unexamined Patent Publication No. 2003-62705 (Patent Document 1) describes a substrate made of one type selected from high-speed steel, carbon tool steel and alloy tool steel in order to improve wear resistance and welding resistance. A tool coated with a DLC film having a hydrogen content of 5 atomic% or less and substantially free of hydrogen is described. Further, a similar tool having a base material of WC-based cemented carbide is described in Japanese Patent Application Laid-Open No. 2003-62706 (Patent Document 2). As a reason for using a hydrogen-free DLC film for coating, paragraph 0011 of Patent Document 1 states that "usually, hydrogen atoms in hard carbon are desorbed from the film at a temperature of about 350 ° C. or higher in the atmosphere. After hydrogen is desorbed, the hard carbon film transforms into graphite and the hardness drops extremely. Such a film is difficult to use in a harsh cutting environment. " ing. A similar description also exists in paragraph 0011 of Patent Document 2. Therefore, Patent Document 1 and Patent Document 2 describe a DLC film containing hydrogen that coats a cutting tool or the like and that can be used even in a harsh cutting environment because the desorption temperature of hydrogen is high. Is not mentioned at all and is not even suggested.

Japanese Patent Application Laid-Open No. 11-92935 (Patent Document 3) describes a hard carbon film (hydrogen-containing DLC film) formed on a base material, and its surface is easily smoothed by contact and sliding with a mating material. Therefore, a technique of a hard carbon coating capable of suppressing excessive wear of a mating material has been disclosed. According to the technique, a high-hardness hard carbon film is first formed on a substrate, and then a low-hardness hard carbon film is formed on the substrate. When this is polished or used without polishing, the second film having a low hardness formed on the outermost surface is abraded, and a flat surface can be easily obtained. However, the high-hardness hard carbon film formed on the base material is merely an amorphous DLC film, not a diamond film made of polycrystalline diamond. Further, Patent Document 3 does not describe the hydrogen gas desorption temperature at the time of heating the DLC film.

According to International Publication No. 2017-026043 (Patent Document 4), a hydrogen-containing DLC film is formed on the surface of a base material by a CVD method in order to ensure low friction and abrasion resistance. The invention of the piston ring is disclosed. In this DLC film toward the substrate surface to the membrane surface, and increase the area of sp ² / sp ³ ratio increases continuously, which is a ratio of sp ² bonds to sp ³ bonds, sp ² / sp ³ ratio The decreasing regions that decrease continuously and the decreasing regions are formed alternately. Therefore, this DLC film is a multilayer film in which hard portions and soft portions are alternately laminated. However, the hard portion is only an amorphous DLC film, not a diamond film made of polycrystalline diamond. Further, Patent Document 4 does not describe the hydrogen gas desorption temperature at the time of heating the DLC film.

Japanese Unexamined Patent Publication No. 5-251586 (Patent Document 5) discloses a method for producing a flat mounting surface of a semiconductor device having a heat dissipation function by utilizing the high thermal conductivity of a diamond film. ing. The method is as follows: a DLC film is formed on the surface of a polycrystalline diamond film formed on a substrate by CVD, and the DLC film and the polycrystalline diamond film are sequentially etched to simplify the surface of the polycrystalline diamond film. It is to flatten to. In the intermediate stage of this flattening step, a film structure composed of two layers in which a diamond film and a DLC film are sequentially formed on the surface of the substrate is formed. However, Patent Document 5 does not describe the composition of the DLC film, the hydrogen gas desorption temperature, and the effect when this film structure is used as a protective film for a cutting tool.

Japanese Patent Application Laid-Open No. 5-123908 (Patent Document 6) describes a tool in which the surface of a tool base material is coated with a hydrogen-containing DLC film by a vapor phase synthesis method, and the composition of the hydrogen-containing DLC film at the tip of the tool edge is described. Tools that have been identified by Raman spectra as being rich in non-diamond components (atypical carbon and graphite components) are described. However, there is no mention of the hydrogen gas desorption temperature from the hydrogen-containing DLC film during heating.

According to Conway, NM J et al. (2000, Non-Patent Document 1), hydrogen-containing tetrahedral amorphous carbon (ta-C: H) in which hydrogen gas or hydrocarbon gas is eliminated at a temperature of 500 to 700 ° C. Is described. However, there is no description of a hydrogen-containing DLC film in which hydrogen gas is desorbed for the first time at a temperature of 800 ° C. or higher, and there is also a reference to the effect of using the carbon film as a protective film for cutting tools and the like. Absent.

Japanese Unexamined Patent Publication No. 2003-62705 Japanese Unexamined Patent Publication No. 2003-62706 JP-A-11-92935 International Publication No. 2017-026043 Japanese Unexamined Patent Publication No. 5-251586 Japanese Unexamined Patent Publication No. 5-123908

Conway, N.M.J et al., Defect and disorder reduction by annealing in hydrogenated tetrahedral amorphous carbon, Diamond and Related Materials, vol. 9, issue 3-6, pp. 765-770, (2000)

As seen above, the conventional technique is a condition in which a hydrogen-containing DLC film can be used as a protective film for a tool such as a cutting tool under a usage environment such as a harsh cutting environment, that is, hydrogen during heating. No mention is made of the high gas desorption temperature. Further, regarding the use of a hydrogen-containing DLC film formed on a diamond base material or a base material coated with a diamond film made of polycrystalline diamond as a protective film for tools such as cutting tools and its effect. Is not mentioned in the prior art literature at all. Furthermore, the prior art does not mention at all the use of a hydrogen-containing DLC membrane, which has a high hydrogen gas desorption temperature during heating, as a self-supporting membrane.
Therefore, an object of the present invention is a protective film for articles such as cutting tools, dies, and optical parts that can be used in a harsh environment by specifying the hydrogen gas desorption temperature during heating. It is an object of the present invention to provide a hydrogen-containing DLC film having mechanical properties such as low friction, low wear and low aggression. A further subject of the present invention is a protective film for an article such as a cutting tool, which is a hydrogen-containing DLC formed on a diamond base material or a base material coated with a diamond film made of polycrystalline diamond. To provide a membrane. A further object of the present invention is to provide a hydrogen-containing DLC film that can be used as a self-supporting film by specifying the hydrogen gas desorption temperature during heating.

The present invention has been made to solve the above problems, and the first aspect of the present invention protects at least a part of the surface of the base material and contains carbon as a main component and 5at. It contains a% or more of hydrogen and has a carbon having an sp ² hybrid orbital component and a carbon having an sp ³ hybrid orbital component, and when heated in a vacuum, the desorption of the contained hydrogen is 800 ° C. or more. It is a carbon film characterized by being produced.

The second aspect of the present invention is the carbon film in which hydrocarbon desorption does not occur at 1000 ° C. or lower when heated in a vacuum.

In the third aspect of the present invention, the base material is diamond, or the base material is a base material having a diamond film formed on the surface thereof, and protects at least a part of the surface of the base material. It is a carbon film.

A fourth aspect of the present invention is the carbon film having a refractive index of 2.4 or more and 2.7 or less and an extinction coefficient of 0.1 or more and 0.2 or less with respect to light having a wavelength of 546 nm.

In the fifth embodiment of the present invention, the film density is 2.6 g / cm ³ or more and less than 3.1 g / cm ³ , and the composition ratio sp of carbon having an sp ² hybrid orbital component and carbon having an sp ³ hybrid orbital component sp. ^The carbon film having ³ / (sp ³ + sp ² ) of 40% or more and less than 60%.

A sixth embodiment of the present invention determines whether or not the hydrogen-containing amorphous carbon film formed on the surface of a substrate having a refractive index of 0.1 or more and an extinction coefficient of 1.0 or more is the carbon film. This is a discrimination method for discriminating, and the hydrogen-containing amorphous carbon film is not damaged at an irradiation intensity of 80 kW / cm ² in CW (continuous wave) laser light irradiation of ultraviolet light having a wavelength of 324 nm, and is close to a wavelength of 785 nm. Infrared light CW laser light irradiation is not damaged at irradiation intensity 1.6 × 10 ³ kW / cm ² , and visible light CW laser light irradiation with wavelength 532 nm is damaged at irradiation intensity 765 kW / cm ^2. It is a discrimination method characterized by having a step of confirming that it is not affected and is damaged at 1.4 × 10 ³ kW / cm ² .

A seventh aspect of the present invention is a method for determining whether or not the hydrogen-containing amorphous carbon film formed on the surface of diamond is the carbon film, and the hydrogen-containing amorphous carbon film is used. On the other hand, when Raman spectroscopy was performed with visible light laser light having an irradiation intensity of 3.8 × 10 ² kW / cm ² , the spectrum of a diamond having a Raman shift of (1329 to 1338) cm ^-1 was not detected, and the irradiation intensity was 8 When Raman spectroscopy was performed with .9 × 10 ² kW / cm ² near-infrared light laser light, a spectrum of diamonds with a Raman shift of (1329 to 1338) cm ^-1 was detected, and Raman was detected with the above visible light laser light. when performing the spectroscopy in the DLC spectrum intensity ratio I _D / I _G of the D and G-peaks is 0.2 or more and 0.5 or less, and, G peak positions 1545 cm ^-1 or 1570 cm ^-1 in the following It is a discrimination method characterized by having a step of confirming that there is.

Eighth forms of the present invention include nitrogen, oxygen, boron, argon, silicon, phosphorus, sulfur, antimony, selenium, tellurium, fluorine, chlorine, astatine, transition metal elements, aluminum, zinc, indium, tin and antimony. , Lead, bismuth. The carbon film containing one or more elements selected from the group.

In the ninth aspect of the present invention, the base material is a carbon film in which the base material is a tool, a mold, a cutting tool, a sliding member, or an ornament.

A tenth aspect of the present invention is a carbon film whose base material is an optical component.

The eleventh aspect of the present invention is an article characterized in that at least a part of the surface is protected by the carbon film.

The twelfth form of the present invention is the carbon film which is a self-supporting film separated from the base material.

According to the first aspect of the present invention, at least a part of the surface of the base material is protected, and carbon is the main component, and 5 at. It contains a% or more of hydrogen and has a carbon having an sp ² hybrid orbital component and a carbon having an sp ³ hybrid orbital component, and when heated in a vacuum, the desorption of the contained hydrogen is 800 ° C. or more. It is possible to provide a carbon film characterized by being produced. The main component is carbon, which means that the carbon film of this embodiment has 50 at. It means that it contains more than% carbon. This carbon film is an amorphous carbon film (DLC film) containing hydrogen.

In general, a carbon film containing hydrogen is desorbed as hydrogen gas when heated in a vacuum, and the carbon film is graphitized and softened accordingly. Since the protective film of a cutting tool used under harsh cutting conditions is exposed to a local high temperature due to frictional heat, it is important to have a highly heat-resistant film in order to ensure mechanical durability. Since the carbon film of this embodiment has an extremely high start temperature of hydrogen gas desorption of 800 ° C. or higher, it has high heat resistance and is suitably used as a highly heat-resistant protective film for covering articles such as cutting tools. Can be done. Further, this carbon film can also be suitably used for a highly heat-resistant mold release film or the like that covers the surface of a mold such as a lens molding mold.
Conventionally, DLC that can be used as a protective film or a release film under conditions that require high heat resistance has been limited to hydrogen-free ta-C or a-C. The present inventor has produced the hydrogen-containing carbon film of the present embodiment by devising a film forming apparatus and film forming conditions, and has made it usable for the above-mentioned high heat resistance application.

The hydrogen-containing carbon film according to the present invention "protects at least a part of the surface of the base material" and may be directly formed on the surface of the base material or an intermediate layer between the base material and the base material. (Or also referred to as an adhesion layer) may be sandwiched between the films. When an intermediate layer is inserted, an object thereof is to ensure sufficient adhesion between the base material (also referred to as a substrate) and the hydrogen-containing carbon film according to the present invention. The thickness of the intermediate layer is, for example, about 0.1 to 10 nm. As the intermediate layer, for example, metals such as Ti, Cr, and W, and nitrides and carbides thereof can be used. Further, the hydrogen-containing carbon film of the present invention does not have to be uniform from the substrate or the intermediate layer toward the surface, and if necessary, the ratio of each component to the composition may be inclined, or hydrogen having a different composition or component may be used. The containing carbon film may be laminated so that the function is exhibited as a whole.

According to the second aspect of the present invention, it is possible to provide the carbon film in which desorption of hydrocarbons does not occur at 1000 ° C. or lower when heated in a vacuum. The carbon film of the present embodiment is characterized in that the start temperature of hydrogen gas desorption is 800 ° C. or higher, and the desorption of hydrocarbons (C _n H _m ) does not occur at 1000 ° C. or lower. The fact that only hydrogen (H ₂ ) having a small molecular weight is desorbed at a temperature of 800 ° C. or higher and hydrocarbons are not desorbed at a temperature of 1000 ° C. or lower means that this carbon film has high heat resistance and accompanies heating. It means that it is less likely to be graphitized or softened. This carbon film is suitable as a highly heat-resistant protective film for covering articles such as cutting tools, and as a highly heat-resistant release film for covering the surface of a mold such as a mold for molding a lens. It can be used.

According to the third aspect of the present invention, the base material is diamond, or the base material is a base material having a diamond film formed on the surface thereof, and at least a part of the surface of the base material is covered. A protective carbon film can be provided. When cutting a composite material consisting of a hard material such as carbon fiber and a soft material with low thermal conductivity such as resin, such as carbon fiber reinforced plastic (CFRP), as a work material, Conventionally, cutting tools in which a base material such as carbon fiber is coated with a diamond film have been used, but it is difficult to ensure the quality of the machined surface due to rare burrs depending on the cutting conditions, and the cutting tool is cut. There was a problem that the blade part was worn and peeled off very rarely. It is considered that the cause is that the diamond film is polycrystalline and has uneven surface and poor flatness, or that the diamond film has high hardness and extremely high internal stress. Further, it requires a high cost to flatten the diamond film by polishing or the like. Therefore, the present inventor further improves the flatness of the cutting tool surface by further coating the diamond film covering the base material of the cutting tool with the hydrogen-containing carbon film of the present invention, resulting in low friction and abrasion resistance. It provides a cutting tool that has properties and low aggression against a material to be cut, and realizes a high-quality machined surface with less generation of burrs.

It is considered that not only the flatness of the surface of the cutting tool but also the high heat resistance of the hydrogen-containing carbon film of the present invention works effectively in realizing a high-quality machined surface. For example, when CFRP containing a resin having a low thermal conductivity is used as the work material, the cutting portion may become locally hot. In the case of a normal hydrogen-containing carbon film, desorption of hydrogen and the like and graphitization occur at a locally high temperature location, and the film softens, so that the function as a protective film cannot be sufficiently fulfilled. However, since the hydrogen-containing carbon film of the present invention is a carbon film in which desorption of hydrogen occurs at 800 ° C. or higher and has high heat resistance, desorption of hydrogen and the like and graphite even when the cutting portion is locally heated to a high temperature. It is possible to provide a protective film for a cutting tool that is less likely to cause burrs, has heat resistance, low friction resistance, abrasion resistance, and low aggression against a material to be cut, and can form a high-quality machined surface with less generation of burrs. ..

According to the fourth aspect of the present invention, it is possible to provide the carbon film having a refractive index of 2.4 or more and 2.7 or less and an extinction coefficient of 0.1 or more and 0.2 or less with respect to light having a wavelength of 546 nm. .. As shown in FIG. 11, in general, the refractive index of hydrogen-free DLC is generally that of diamond (refractive index 2.4, extinction coefficient 0.0) and graphite (refractive index 2.7, extinction coefficient 1.4). It takes an intermediate value, and the film density and the refractive index have an almost linear relationship with a negative slope. In addition, the extinction coefficient of hydrogen-free DLC decreases as the film density increases. That is, the closer the film density is to diamond, the smaller the extinction coefficient and the more transparent it becomes. Further, regarding hydrogen-containing DLC, the refractive index is greatly reduced by the introduction of hydrogen, and the extinction coefficient is once increased and then decreased. The present inventor has determined that the hydrogen-containing carbon film according to the present invention has a refractive index of 2.4 or more and 2.7 or less and an extinction coefficient of 0.1 or more and 0.2 or less with respect to light having a wavelength of 546 nm. I found it. Since the refractive index is 2.4 or more and 2.7 or less and the extinction coefficient is 0.1 or more and 0.2 or less, the hydrogen content of the hydrogen-containing carbon film according to the present invention is an upper limit (about 10 at). There is a lower limit (about 5 at.%). Therefore, this hydrogen-containing carbon film can maintain a relatively high hardness while imparting low friction and low aggression to the film by containing hydrogen, and can be suitably used as a protective film for cutting tools and the like. it can.

According to the modified form of this embodiment, it is possible to provide the carbon film having a refractive index of 2.5 or more and 2.6 or less and an extinction coefficient of 0.1 or more and 0.2 or less with respect to light having a wavelength of 546 nm. The hydrogen-containing carbon film in this modified form has an extinction coefficient within the above range and a refractive index of 2.5 or more and 2.6 or less. Therefore, by containing hydrogen, the film has low friction and low aggression. Can be maintained at a relatively high hardness, and can be more preferably used as a protective film for cutting tools and the like.

According to the fifth embodiment of the present invention, the film density is 2.6 g / cm ³ or more and less than 3.1 g / cm ³ , and the composition of carbon having an sp ² hybrid orbital component and carbon having an sp ³ hybrid orbital component. The carbon film having a ratio of sp ³ / (sp ³ + sp ² ) (hereinafter, referred to as sp ³ composition ratio) of 40% or more and less than 60% can be provided. In general, the film density of hydrogen-free DLC is approximately intermediate between diamond (density 3.5 g / cm ³ , sp ³ composition ratio 100%) and graphite (density 2.3 g / cm ³ , sp ³ composition ratio 0%). The hardness (nano-indentation hardness) increases approximately in proportion to the cube of the film density. Further, for hydrogen-containing DLC, the film density becomes smaller and the hardness becomes smaller as hydrogen enters. The present inventor has determined that the hydrogen-containing carbon film according to the present invention has a film density of 2.6 g / cm ³ or more and less than 3.1 g / cm ³ and a sp ³ composition ratio of 40% or more and less than 60%. I found it. Since the hydrogen-containing carbon film according to the present invention has a film density and sp ³ composition ratio within the above ranges, the film is provided with low friction and low aggression by containing hydrogen, and has a relatively high hardness. It can be maintained and can be suitably used as a protective film for cutting tools and the like.

According to the sixth embodiment of the present invention, whether or not the hydrogen-containing amorphous carbon film formed on the surface of the base material having a refractive index of 0.1 or more and an extinction coefficient of 1.0 or more is the carbon film. This is a discrimination method for discriminating whether or not the hydrogen-containing amorphous carbon film is not damaged at an irradiation intensity of 80 kW / cm ² in CW (continuous wave) laser light irradiation of ultraviolet light having a wavelength of 324 nm, and has a wavelength of 785 nm. in CW laser irradiation of near-infrared light of not damaged by irradiation intensity ^{1.6 × 10 3 kW / cm 2} , the CW laser beam irradiation with visible light of wavelength 532nm is irradiated intensity 765kW / cm ² Can provide a discriminant method characterized by having a step of confirming that it is not damaged and is damaged at 1.4 × 10 ³ kW / cm ² .
In general, the laser light damage property of the DLC film formed on the surface of the substrate is affected by the reflectance of the substrate. When the reflectance of the base material is high, the laser light incident on the DLC film is reflected at the interface between the DLC film and the base material and travels in the film again, so that the DLC film transfers the incident light and the reflected light. This is because there is a possibility of being damaged by the superimposed light. For example, even if the DLC film formed on the surface of diamond is not damaged by laser light of a certain intensity and wavelength, the DLC film formed on the surface of WC-based cemented carbide under the same conditions has the same intensity and wavelength. It can happen that it is damaged by the laser light of. The reason why the base material is limited to "refractive index of 0.1 or more and extinction coefficient of 1.0 or more" is to clarify the reflection characteristics of the base material.

In general, the resistance of a hydrogen-containing DLC film to laser light damage is higher as the hydrogen content is smaller, and is higher as the sp ³ composition ratio is larger. Further, even if the laser light intensity is the same, the above resistance differs depending on the wavelength of the laser light. This is because the optical characteristics such as the refractive index and the extinction coefficient of the hydrogen-containing DLC film differ depending on the wavelength of light. The present inventor has found a method for discriminating a carbon film according to the present invention by using a damage threshold value of laser light intensity in which laser light damage is caused by laser light of each wavelength of ultraviolet, near infrared, and visible wavelengths. Regarding the hydrogen-containing amorphous carbon film formed on the surface of the base material, the damage threshold value for the ultraviolet light laser light is larger than 80 kW / cm ² , and the damage threshold value for the near infrared light laser light is 1.6 × 10. ³ larger than kW / cm ^2, if the visible light greater and less than 1.4 × 10 ³ kW / cm ² damage threshold than 765kW / cm ² with respect to the laser beam, the hydrogen-containing amorphous carbon film, the It can be identified as the carbon film according to the invention.

According to the seventh aspect of the present invention, it is a determination method for determining whether or not the hydrogen-containing amorphous carbon film formed on the surface of diamond is the carbon film, and the hydrogen-containing amorphous carbon. When Raman spectroscopy was performed on the film with visible light laser light with an irradiation intensity of 3.8 × 10 ² kW / cm ² , the spectrum of diamond with a Raman shift of (1329 to 1338) cm ^-1 was not detected and irradiation was performed. When Raman spectroscopy was performed with near-infrared light laser light with an intensity of 8.9 × 10 ² kW / cm ² , a spectrum of diamonds with a Raman shift of (1329 to 1338) cm ^-1 was detected, and the above visible light laser light was detected. in when performing Raman spectroscopy, the DLC spectrum intensity ratio I _D / I _G of the D and G-peaks is 0.2 or more and 0.5 or less, and, G peak positions 1545 cm ^-1 or more 1570 cm ^-1 It is possible to provide a discrimination method characterized by having a step of confirming that:
In general, the shape of the Raman spectroscopic spectrum of the DLC film differs depending on the sp ³ composition ratio and the hydrogen content, and further depends on the wavelength of the incident laser light. The present inventor has found a method for discriminating the carbon film of the present invention by utilizing the shape of the Raman spectroscopic spectrum when the visible light laser light and the near infrared light laser light are incident. Since the spectrum of the diamond is not detected when Raman spectroscopy is performed on the hydrogen-containing amorphous carbon film which is the target film for discrimination with the visible light laser light, it can be understood that the target film is not ta-C. .. Further, since the spectrum of the diamond is detected when Raman spectroscopy is performed with the near-infrared laser light, it can be seen that the target film is not a-C. Therefore, the target film is a DLC film (ta-C: H or a-C: H) that substantially contains hydrogen. Here, the target film is further discriminated by the intensity ratio I _D / _IG and the G peak position when Raman spectroscopy is performed with visible light laser light. The intensity ratio I _D / I _G of the hydrogen-containing DLC film increases as the hydrogen content increases, also tends to become larger as the sp ³ configuration ratio decreases. Further, the G peak position of the hydrogen-containing DLC film having a hydrogen content in the range of 5 to 20% does not depend much on the hydrogen content and tends to increase as the sp ³ composition ratio increases. Therefore, the intensity ratio I _D / I _G of the target film is not less than 0.5, and if the G peak position is 1545 cm ^-1 or more, the hydrogen content of the target layer is not more than about 10%, And the sp ³ composition ratio is about 40 at. It turns out that it is more than%. In addition, the intensity ratio I _D / I _G of the target film is not less than 0.2, and if the G peak position is 1570 cm ^-1 or less, the hydrogen content of the target layer is located at about 5% or more And the sp ³ composition ratio is about 60 at. It turns out that it is less than%. Therefore, it can be determined that the target film is the carbon film according to the present invention.

According to a variant of this embodiment, in addition to the above steps, the intensity ratio I _D / I _G of the D and G-peaks is 0.3 or more and 0.5 or less, and, G peak position 1548Cm ^-1 It is possible to provide the discrimination method having a step of confirming that the size is 1555 cm ^-1 or less. The intensity ratio I _D / I _G of the target film is 0.5 or less, and if the G peak position is 1548Cm ^-1 or more, the hydrogen content of the target layer is not more than about 10%, and sp ³ Composition ratio is about 45 at. It turns out that it is more than%. In addition, the intensity ratio I _D / I _G of the target film is not less than 0.3, and if the G peak position is 1555Cm ^-1 or less, the hydrogen content of the target layer is located at about 5% or more And the sp ³ composition ratio is about 55 at. It turns out that it is less than%. Therefore, it can be determined that the target film is the carbon film of the present invention.

According to the eighth embodiment of the present invention, nitrogen, oxygen, boron, argon, silicon, phosphorus, sulfur, antimony, selenium, tellurium, fluorine, chlorine, astatine, transition metal elements, aluminum, zinc, indium, tin. The carbon film containing one or more elements selected from the group consisting of, lead and bismuth can be provided. By adding other elements in addition to hydrogen, various properties can be imparted to the carbon film according to the present invention, and variations in film physical properties can be expanded. For example, nitrogen is for the purpose of improving wear resistance and hardness, boron is for the purpose of increasing hardness, silicon is for the purpose of improving scratch strength or friction life or heat resistance, and each element of halogen is for the purpose of improving friction life. Alternatively, the metal element can be added for the purpose of improving the low friction property or imparting water repellency, or for the purpose of improving the adhesive force or imparting conductivity.

According to the ninth aspect of the present invention, the base material can provide a carbon film which is a tool, a mold, a cutting tool, a sliding member, or an ornament. The carbon film according to the present invention has low friction and low wear, and has high heat resistance because the start temperature of hydrogen gas desorption is as high as 800 ° C. or higher, and is a slider for cutting tools, cutting tools, and hard disk drives. It can be suitably used as a highly heat-resistant protective film for covering a sliding member such as a piston or a cylinder, or an article such as a decorative item. Further, the carbon film according to the present invention can also be suitably used for a highly heat-resistant mold release film or the like that covers the surface of a high-temperature mold such as a lens molding mold.

According to the tenth aspect of the present invention, it is possible to provide a carbon film whose base material is an optical component. Since the carbon film according to the present invention transmits visible light and particularly near-infrared light well while having low wear resistance and high heat resistance, it is a protective film or an antireflection film for optical components such as infrared optical components. Etc., it can be preferably used.

According to the eleventh aspect of the present invention, it is possible to provide an article characterized in that at least a part of the surface is protected by the carbon film.

According to the twelfth aspect of the present invention, the carbon film which is a self-supporting film separated from the base material can be provided. DLC films are characterized by their mechanical strength at nanoscale film thickness. In recent years, as applications of DLC membranes, applications such as electron transmission membranes, filtration filters, and thin film targets for laser-driven ion acceleration have been attracting attention as self-supporting membranes separated from a substrate. Since the DLC film is formed on the underlying substrate, a process of self-supporting is required to use it as a self-supporting film. For example, a water-soluble sacrificial layer made of sodium chloride (NaCl) or silk fibroin, which is a kind of protein, is formed on the base material, a DLC film is formed on the sacrificial layer, and then the base material is put into water. Upon immersion, the sacrificial layer dissolves and the target membrane is separated from the substrate. A self-supporting membrane can be obtained by scooping up this target membrane with a porous substrate. By the way, since the DLC self-supporting film has a high internal stress, the DLC film itself cannot support the internal stress in the self-supporting film state separated from the base material, and wrinkles and tears of the film are likely to occur. This self-destruction of the membrane is the greatest concern for DLC self-supporting membranes. Since the carbon film according to the present invention substantially contains hydrogen and the sp ³ composition ratio is also in the range of about 40 to 60%, the internal stress is higher than that of the hard hydrogen-free DLC film (ta-C). Slightly low and less likely to cause self-destruction of the membrane. Therefore, the carbon film according to the present invention can be suitably used as a self-supporting film separated from the base material, particularly in applications requiring heat resistance.

FIG. (1A) is a table diagram summarizing the film forming conditions, the composition ratio, and the mechanical properties of the carbon film according to the present invention and the carbon film of the comparative example. FIG. (1B) is a table diagram that also summarizes the optical properties. FIG. 2 is a graph showing the results of temperature desorption gas analysis (TDS analysis) of the carbon film. FIG. 3 is a graph showing the relationship between the hydrogen content of the carbon film and the hydrogen (H ₂ ) detection temperature in the TDS analysis. FIG. (4A) is a photograph of the results of a cutting test using a tool coated with the carbon film. FIG. (4B) is a schematic view of the exit side observation surface. FIG. 5 is a photographic view showing the result of the laser damage test of the carbon film. FIG. 6 is a photographic view showing the result of another laser damage test of the carbon film. FIG. 7 is a photographic view showing the result of another laser damage test of the carbon film. FIG. (8A) is a graph showing the results of Raman spectroscopic analysis of the carbon film by visible light laser light. FIG. (8B) is a graph showing the results of Raman spectroscopic analysis of the carbon film by near-infrared laser light. FIG. 9 is a block diagram of a TDS analyzer used for TDS analysis of a sample. FIG. 10 is a classification diagram showing a rough classification of carbon films based on optical constants. FIG. 11 is a graph showing a general relationship between the film density of the carbon film and the optical constant. FIG. 12 is a graph showing the wavelength dependence of the optical constants of the carbon film. FIG. 13 is an explanatory diagram showing a simulation result of the electric field strength inside and outside the carbon film. FIG. 14 is a graph showing Raman spectroscopic spectra of the carbon film before and after laser damage. FIG. 15 is a graph showing Raman spectroscopic spectra of another carbon film before and after laser damage. FIG. 16 is an explanatory diagram showing the dependence of the strength ratios I _D / _IG and G peak positions of the carbon film on the gas flow rate and the bias voltage. FIG. 17 is an explanatory diagram showing the dependence of the strength ratios I _D / _IG and G peak positions of the carbon film on the hydrogen content. Figure 18 is an explanatory view showing the relationship between the intensity ratio I _D / I _G and G peak position of the carbon film. FIG. 19 is an explanatory diagram showing the dependence of the hydrogen content and sp ³ composition ratio of the carbon film on the gas flow rate or the bias voltage.

Next, a mode for carrying out the hydrogen-containing carbon film according to the present invention will be described in detail with reference to the drawings.

<1. Film formation method and equipment>
(Vacuum arc vapor deposition apparatus) A T-shaped filtered arc vapor deposition (T-FAD) apparatus using a graphite cathode was used for preparing a sample, that is, for forming a carbon film. T-FAD is a kind of vacuum arc deposition method. In an arc discharge in a vacuum, one or several cathode points are formed on the surface of the cathode material, and the cathode material evaporates violently. Since the cathode point becomes hot, a large amount of thermions are emitted at the same time. The evaporated material from the cathode point is ionized by the thermions immediately after evaporation. This ion is accelerated by the potential difference and heads toward the anode (usually the film forming chamber body).

(Dreplet Removal) When trying to obtain a high-quality film, the drawback of the vacuum arc deposition method is that macrofine particles of the cathode material called droplets are secondarily released from the cathode point. When this droplet is mixed in the produced film, it impairs the flatness, uniformity, and homogeneity of the film, and may be a starting point for causing film peeling and performance deterioration. In the case of a graphite cathode, the droplets are solid and travel through the duct while reflecting off without adhering to the duct wall. The T-FAD device was devised by the present inventor to remove such droplets, has a T-shaped filter duct, bends the plasma at a right angle at the T-shaped point, transports it, and drops it. The lett is collected by a duct in the direction facing the cathode (International Publication WO2016-021671). Rather than collecting the droplets on the inner wall of the duct or bellows baffle as in the conventional filtered arc device, the T-FAD device collects the droplets on the entire duct facing the cathode, so it reflects especially on the inner wall. Effective in removing graphite droplets.

(T-FAD device) In the T-FAD device, a graphite cathode and a metal anode are arranged at one end of a T-shaped filter duct, and a DC vacuum arc discharge is generated between them. The magnetic field generated by the electromagnetic coil provided outside the anode draws out the arc plasma generated between the anode and the cathode in a beam shape in the duct direction. The magnetic field generated by the electromagnetic coil arranged outside the T-shaped portion bends the plasma beam and guides it toward the film forming chamber and the substrate (base material). The plasma beam is scanned up, down, left and right using two sets of electromagnetic coils arranged at the connection point between the duct and the film formation chamber, and the work table is rotated around three axes in conjunction with it and attached to the work table. A film formation range is secured on the formed substrate, and a uniform distribution is obtained. A T-FAD apparatus can be preferably used for forming a carbon film according to the present invention, but an off-plain double bend (Off-plain double bend) can be used as long as the apparatus can effectively remove graphite droplets. It is also possible to use other types of filtered arc deposition (FAD) equipment such as) type filtered arc deposition equipment. In the present specification, unless otherwise specified, "board" and "base material" are used in the same meaning.

(Atmosphere / Pressure) In the FAD apparatus, a carbon film containing other elements such as hydrogen can be formed by introducing an atmosphere gas. In the T-FAD apparatus used for preparing the sample this time, the introduction of gas is controlled by the gas type selection means, the gas flow rate control means, and the process pressure (pressure in the film forming chamber) measuring means. .. As the gas type, no introduction gas, hydrogen (H ₂ ), acetylene (C ₂ H ₂ ), ethylene (C ₂ H ₄ ) and the like can be selected. By controlling the introduction of gas, the hydrogen content and sp ³ composition ratio of the membrane can be adjusted. The explanatory diagram is shown in FIG. In general, the higher the gas flow rate, the higher the hydrogen content of the membrane. The gas types are C ₂ H ₄ , C ₂ H ₂ , and H ₂ in order from the one having the highest hydrogen content in the film to be formed. This is because the number of hydrogen atoms (hydrogen ions) that contribute to film formation increases. In general, the larger the gas flow rate, the smaller the sp ³ composition ratio of the membrane. The gas types are C ₂ H ₄ , C ₂ H ₂ , and H ₂ in order from the one having the lowest sp ³ composition ratio of the formed film. This is because the energy of C ⁺ ions is reduced by the collision with the gas. In the case of no introduction gas, a hydrogen-free DLC film can be formed, but care must be taken because if moisture or the like adheres to the chamber wall surface, hydrogen-containing DLC may occur. The carbon film according to the present invention is a hydrogen-containing DLC film containing substantially hydrogen, which is formed by explicitly introducing a gas, and has a hydrogen content of about 5 at. % Or more.

(Deposition temperature) The film formation temperature refers to the temperature of the base material on which the film is formed, or more precisely, the temperature of the film itself growing during the film formation. When the film formation temperature exceeds 100 ° C., the DLC generally softens and the film density decreases. In the case of hydrogen-free DLC, if the film formation temperature exceeds 150 ° C., ta-C cannot be formed and becomes a-C. If the arc current is increased or the ion flux r is increased, the film forming speed is increased, but the film forming temperature is raised and the film density is lowered accordingly. There is a trade-off between the film formation rate (and film formation temperature) and the film density.

(Substrate (base material) bias) The substrate bias, or more accurately, the substrate applied bias voltage, is a negative DC voltage or pulse voltage applied to the substrate (base material) on which film formation is performed. By changing the substrate bias, the density of the film and the like can be controlled. The explanatory diagram is shown in FIG. Generally, in the case of hydrogen-containing DLC, if the introduced gas is C ₂ H ₄ or C ₂ H ₂ , the larger the substrate bias (absolute value), the lower the hydrogen content of the membrane. This is because H is released from the membrane by the ion impact. Further, in general, the larger the substrate bias (absolute value), the smaller the sp ³ composition ratio. As for the gas types, H ₂ , C ₂ H ₂ , and C ₂ H ₄ are in order from the one having the highest sp ³ composition ratio of the film to be formed. This is because the energy of C ⁺ ions becomes excessive due to the acceleration due to the bias voltage, and the sp ³ bond cannot be formed. The substrate bias may be a DC voltage, but by using a pulse voltage, the charge accumulated on the substrate, which causes non-uniformity in film formation, is released during the non-application time of the voltage in the pulse period, and the film thickness is increased. It is possible to improve the uniformity and form a high-quality carbon film without geometric defects such as pinholes.

(Substrate (base material) bias and film formation temperature) The larger the absolute value of the negative voltage of the substrate bias, the higher the film formation temperature. Although there are slight differences depending on the gas flow rate and the substrate bias of DC voltage or pulse voltage, the film formation temperature is generally less than 80 ° C when the substrate bias is -100V, and 75 to 110 ° C when the substrate bias is -500V. If it is 1000 V, it is about 130 to 180 ° C.

(Film thickness control) In order to control the film thickness, it is necessary to measure the film thickness. The reflectance of the film in the film formation chamber was measured at a plurality of wavelengths, and the film thickness was determined from the interference pattern. In vacuum arc vapor deposition, the film thickness is not constant even if other film thickness conditions are the same due to the reduction of cathode material, etc. However, by performing additional film deposition, the desired film is generally within ± 5%. You can get the thickness. In the follow-up film formation, the film formation time assuming the maximum film formation rate is first set, the first film formation is performed with the target film thickness of 90%, and then the film thickness is measured as described above. The actual film formation rate of this time is calculated, and the second method is to repeat the process of forming a film aiming at 90% of the remaining film thickness based on the film formation rate. The error can be within ± 5% for the second time and within ± 1% for the third time.

<2. TDS analysis>
(Motivation) In order to know the composition and preparation method of the carbon film with high heat resistance, thermal desorption gas analysis (TDS analysis, Thermal Desorption Spectroscopy) was performed.
(Sample preparation) For the samples (# 1 to # 10) to be analyzed by TDS, the thickness of 400 nm is targeted on the <100> surface of the silicon wafer (n-type Si substrate) as the base material by the above T-FAD apparatus. It is a carbon film formed as. The atmosphere (gas type, gas flow rate, process pressure) and substrate bias, which are the film forming conditions, are as shown in the table of FIG. For comparison, TDS analysis was also performed on the silicon wafer itself (referred to as sample # 0) that did not form a film. Samples # 1 to # 3 are hydrogen-free carbon films, and samples # 4 to # 10 are hydrogen-containing carbon films. Samples # 5 and # 6 are implementation samples of the carbon film according to the present invention, and the others are comparative samples.

(TDS analyzer) TDS analysis is a method of heating a sample in a vacuum and identifying and quantifying the gas released from the sample with a gas analyzer. We have a focused irradiation infrared vacuum furnace (Thermo Riko Co., Ltd., IVF298W) equipped with a programmed temperature controller (Thermo Riko Co., Ltd., TP300RF) and a mass filter type gas analyzer (QMS) (ULVAC, REGA). TDS analysis was performed using the TDS analyzer 1 shown in FIG. 9 in which -101) was combined. In the infrared vacuum furnace, the sample 10 is placed in a recess of a quartz sample table 13 having a depth of 0.5 mm. The size of the sample must be within 10 mm both vertically and horizontally and less than 5 mm thick. A thermocouple 11 for temperature measurement is arranged at a position 5 mm above the center point 12 of the recess of the sample table 13, and the temperature of the sample can be measured with an accuracy of about ± 1 ° C. The inside of the infrared vacuum furnace and the QMS (quadrupole mass spectrometer) communicate with each other via the main valve MV. QMS ionizes the inflowing gas, sends the generated ions to the region where the vibrating quadrupole electric field exists, and selects and detects it based on its specific charge, so that the amount of gas released from the sample per unit time (QMS) The number of molecules) can be detected as an ion current value for each mass number. The QMS measurement mode includes a scan mode and a trend mode. In scan mode, the mass spectrum is known and the type of released gas is known. In the trend mode, the change over time of the mass spectrum can be seen. Since the time change of the temperature is known, the outgassing temperature can be found from the measurement result in the trend mode.

(Heating conditions) The sample was heated by infrared irradiation under a pressure of 5.0 × 10 ^-4 Pa or less as the base pressure while monitoring the temperature. The heating rate was 5 ° C./min, and the ultimate temperature was 1000 ° C. or 1200 ° C.
(Mass spectrometry conditions) The QMS ionization voltage was set to 50 eV, the mass sampling rate was set to 200 ms / amu, the measurement interval was set to 4 s, the measured mass number range was set to 1 to 60 amu, and the measurement mode was set to the trend mode. Here, "amu" is assumed to mean a unified atomic mass unit.

(TDS analysis result) Fig. (2A) shows the result of mass spectrometry by TDS analysis of comparative sample # 0 consisting only of the base material (n-type Si substrate), and the ion current corresponding to each molecular weight on the horizontal axis. It is a graph shown in the vertical axis. Since no peak of outgassing is observed at a specific temperature at any molecular weight, FIG. (2A) detects a very small amount of molecules released from the inner wall of the infrared vacuum furnace, etc., not derived from the sample. It is considered to be.
FIG. (2B) is a graph showing the results of similar mass spectrometry for comparative sample # 2 on which a hydrogen-free carbon film was formed. Similar to Comparative Sample # 0, no outgassing peak is observed at any particular temperature at any molecular weight.
FIG. (2C) is a similar graph of Example # 5 on which a hydrogen-containing carbon film was formed. A peak outgassing was detected for molecular weight 2 (hydrogen H ₂ ). The temperature of the detection peak is 950 ° C, the detection start temperature is 930 ° C, and the detection end temperature is 980 ° C. For other molecular weights (hydrocarbons C _n H _m ), no outgassing peaks are seen at specific temperatures.
FIG. (2D) is a similar graph of comparative sample # 8 on which a hydrogen-containing carbon film is formed. A peak outgassing was detected for molecular weight 2 (hydrogen H ₂ ). The temperature of the detection peak is 720 ° C, the detection start temperature is 670 ° C, and the detection end temperature is 800 ° C. For other molecular weights (hydrocarbons C _n H _m ), no outgassing peaks are seen at specific temperatures.

Table 1 shows the hydrogen (H ₂ ) detection temperature for each sample (# 0 to # 10). In the table, for the samples (# 1 to # 3), the description "none" means that the release of hydrogen gas is not detected at a temperature of 1200 ° C. or lower. Further, the detected peak temperature means the temperature at which the current value of the ion current (hereinafter referred to as the subtracted current value) obtained by subtracting the background is maximized in the graph of FIG. Further, the detection start temperature and the detection end temperature mean the temperatures at which the subtraction current value is 0.1 times the peak value of the subtraction current value in the graph of FIG. Here, the background current value is, for example, the logarithmic value of the ion current value in the vicinity of each peak of outgassing in the graph of FIG. 2, which is a quadratic function of temperature (representing the background) and a Gaussian function (outgassing). Can be identified by fitting with the sum of). In any of the samples, no peak of outgassing was detected in the temperature range of 1000 ° C. or lower for other molecular weights (hydrocarbon C _n H _m ) other than hydrogen (H ₂ ).

FIG. 3 is a graph showing the hydrogen (H ₂ ) detection temperature of each sample shown in Table 1 with the hydrogen content of the carbon film on the horizontal axis. The method for measuring the hydrogen content will be described later. The circle indicates the detection peak temperature, and the horizontal bar indicates the detection start temperature or detection end temperature. The comparative samples (# 1 to # 3) on which a hydrogen-free carbon film was formed and the hydrogen content of the carbon film were 2 at. Comparative sample # 4, which is%, is not shown because hydrogen gas is not detected at 1200 ° C. or lower. For samples # 5 to # 10 on which a hydrogen-containing carbon film is formed, the hydrogen (H ₂ ) detection temperature tends to decrease as the hydrogen content increases. In order for the detection start temperature of hydrogen (H ₂ ) to be 800 ° C. or higher, the hydrogen content of the carbon film is about 15 at. Must be less than or equal to%, about 10 at. % Or less is more preferable.

In the table of FIG. 1, the hydrogen content (at.%), Hardness (GPa), film density (g / cm ³ ), sp ³ composition ratio (%), and 3 measured for the carbon film of each sample. The refractive index and extinction coefficient at one wavelength (400 nm, 546 nm, 800 nm) and the intensity ratios _ID / _IG and G peak positions (cm ^-1 ) in Raman spectroscopic analysis are shown. The hydrogen content (at.%) Was measured using an apparatus (1 MW Tandetron Accelerator, University of Tsukuba) by the elastic recoil detection analysis (ERDA) method. The hardness (GPa) and film density (g / cm ³ ) are determined by the nano indenter (Triboindenter TI950, Hysitron) and the X-ray reflectivity (X-ray reflectivity) method, respectively (X'Pert PRO MRD, PAnallytical). Was measured using. The sp ³ composition ratio (%), that is, the ratio sp ³ / (sp ³ + sp ² ) is determined by the device (Newsval BL09A, National Research) by the X-ray absorption fine structure (NEXAFS) method near the absorption edge. It was measured using the development corporation RIKEN). The refractive index and extinction coefficient at each wavelength were calculated by fitting the reflectance measured with a spectral reflectance measuring device (USPM-RU-2, Olympus) with the optical thin film analysis software FilmStar. The intensity ratios I _D / _IG and G peak position (cm ^-1 ) were determined by visible light microscopic Raman spectroscopic measurement, and the method and equipment used will be described later for the carbon film formed on the diamond substrate. The same is true.

<3. Cutting test>
(Motivation) A drill cutting test was conducted to find out what kind of carbon film should be applied to the drill to obtain a high-quality machined surface for difficult-to-cut materials such as CFRP.
(Preparation of sample drill) First, a drill used for a cutting test (hereinafter referred to as a sample drill) will be described. The sample drill coated with a carbon film (# 1 to # 10; the same symbol as the sample in TDS analysis is used for simplicity) is a commercially available drill D-STAD-1915 (diamond coated cemented carbide for CFRP) as a base material. Carbide triple angle drill, OSG Co., Ltd., drill diameter 4.864 mm, groove length 39 mm, total length 89 mm, shank diameter 4.864 mm, tip angle 120 °, with thinning, tip length 8.2 mm, diamond film thickness 16 μm) This is a drill formed by forming a carbon film on the surface of a portion including a body with the above-mentioned T-FAD apparatus with a target thickness of 500 nm. The film forming conditions are the same as those shown in the table of FIG. For comparison, a cutting test was also conducted using a commercially available drill D-STAD-1915 itself (referred to as sample drill # 0) that does not form a carbon film.
(Work material) CFRP (plain weave cloth material, carbon fiber: PAN-based, resin: thermosetting resin, thickness 5 mm, number of layers 13) was used as the work material.

(Test method and result evaluation method) In an environment of room temperature of 25 ° C. and humidity of 43%, the work material was drilled and cut using a sample drill (# 0 to # 10). The rotation speed of the sample drill is fixed at 2000 rpm, the Z-axis feed speed (mm / min) is switched to 6 stages of 100, 200, 300, 400, 500, 600, and drilling is performed for each Z-axis feed speed. Cutting was performed. FIG. (4A) is a photographic view of the perforation observed from the outlet side. First, the quality of cutting and drilling is visually evaluated.

(Continued from the result evaluation method) Next, a more objective evaluation method for processed quality will be described. For each perforation, all holes were photographed from the outlet side with a digital microscope Dino-Lite (Sanko Co., Ltd., AM-7915MZT). Shape parameters such as D _max and D _nom were measured based on the image, and three indexes (peeling range rate, peeling area rate, and synthetic peeling rate) for evaluating the peeling rate were calculated.
Here, the definition of the shape parameter is as follows. FIG. (4B) schematically shows the captured image. The white circular area is the perforation, and the gray area around it is the peeling point. The gray part protruding into the white circular area is the burr. In the figure, D _max represents the diameter of the smallest concentric circle including all peeling points, and D _nom represents the nominal diameter of the perforation. Further, A _max = π (D _max / 2) ² represents the area of the smallest concentric circle including all the peeled points, and A _nom = π (D _nom / 2) ² represents the nominal area of the perforation. In addition, A _Del is the area of the peeled portion, and includes the area of the uncut portion (burr) extending into the hole.
Furthermore, the three indicators of the release rate peeling range rate F _D, peeling area ratio DF, the definition of synthetic peeling rate F _da is as follows.
_{F D = (D max -D nom} ) / D nom,
DF = A _Del / A _nom ,
_{F da = F D + (F} D 2 -F D) · A Del / (A max -A nom).

(Visual results) First, the visual evaluation of the results of the cutting test will be described. As shown in FIG. (4A), the drilling of the sample drill # 5 according to the embodiment of the present invention has burrs regardless of the Z-axis feed speed.
No (outer residue of geometric shape) is seen at the corner edges of the part, resulting in an extremely high quality machined surface. On the other hand, as for the comparative example, which of the sample drill # 0 having no carbon film formed, the sample drill # 2 having a hydrogen-free carbon film formed, and the sample drill # 8 having a low hydrogen gas desorption temperature. It can be seen that burrs are also generated in the above, and in particular, the higher the Z-axis feed speed, the more likely the burrs are to occur.

(Result of peeling rate) Next, the quality evaluation of the machined surface by the three indexes of the peeling rate will be described. Table 1 shows the peeling range ratio, the peeling area ratio, and the synthetic peeling ratio measured by the above method for each of the sample drills (# 0 to # 10). No cutting experiments have been conducted on sample drills # 7 and # 9, and no data are available. However, the three carbon films (# 7, # 8, # 9) are carbon films that show almost the same composition, mechanical properties, and optical properties, although the gas type and gas flow rate are different, so that they are different from the sample drill # 7. It can be estimated that the result of the cutting experiment for # 9 is similar to that of the sample drill # 8.
Focusing on the peeling area ratio, which is a two-dimensional index, the sample drills # 5, # 6, and # 8 are excellent, and the peeling area ratio is less than half that of other sample drills. Focusing on the peeling range ratio, which is a one-dimensional index, the sample drills # 6 and # 5 are excellent, and the sample drill # 8 has a peeling range ratio that is 50% larger than that of the best sample drill # 6. There is. Therefore, from the comprehensive viewpoint of both, the quality of the machined surface by the sample drills # 6 and # 5 is excellent. Looking at the synthetic peeling rate, the synthetic peeling rate of these two sample drills is smaller than the others.

(Discussion) As can be seen from Table 1, the feature that distinguishes the carbon films # 5 and # 6 according to the present invention from the carbon films of other comparative examples is, firstly, that they substantially contain hydrogen, in other words. For example, hydrogen is added to 5 at. It is a carbon film containing% or more, and secondly, it is a carbon film having a hydrogen (H ₂ ) detection start temperature of 800 ° C. or higher in TDS analysis in vacuum. Since the carbon film according to the present invention substantially contains hydrogen, it is excellent in low friction and low aggression against the material to be cut. Further, the carbon film according to the present invention is a carbon film in which desorption of hydrogen occurs at 800 ° C. or higher and has high heat resistance. It is possible to provide a protective film for cutting tools that is less likely to occur, has heat resistance, low friction resistance, abrasion resistance, and low aggression against the material to be cut, and can form a high-quality machined surface with less burrs. Conceivable.
The sample drill (# 5, # 6) having a carbon film formed according to the present invention is superior to the sample drill (# 0), which is a diacoat drill itself having no carbon film formed, in terms of quality of the machined surface. It is also interesting that there is. It is considered that the cause is that the flatness of the surface of the diamond film can be improved and the aggression against the material to be cut can be alleviated by forming the carbon film according to the present invention.

<4. Laser resistance test>
(Motivation) A laser resistance test was conducted to find out the optical properties that distinguish the carbon film according to the present invention from the carbon film according to the comparative example.
(Sample preparation) The samples (# 1 (WC) to # 10 (WC)) to be subjected to the laser resistance test have a thickness of 500 nm on the surface of the WC-based cemented carbide substrate as the base material by the above T-FAD apparatus. It is a carbon film formed as a target. The atmosphere (gas type, gas flow rate, process pressure) and substrate bias, which are the film forming conditions, are as shown in the table of FIG.

(Equipment and optical system used) Laser Raman microdifferential photophotometer (NRS-7100, Nippon Kogaku Co., Ltd.) selectively uses any of the three laser light sources, and ultraviolet light CW laser light with a wavelength of 324 nm. The measurement point of the sample is irradiated with visible light CW laser light having a wavelength of 532 nm or near-infrared light CW laser light having a wavelength of 785 nm. A dimming device capable of taking 6 levels of optical density (OD value) including the open state is provided between the laser light source and the measurement point, and the laser intensity at the measurement point also changes in 6 levels. The relationship between the OD value of the dimmer and the laser intensity of each wavelength is shown in Table 2 below. Here, the laser intensity means a value obtained by dividing the laser power by the area of a circular spot at the measurement point. The spot diameter (radius) of the laser light of each wavelength is 2 μm for ultraviolet light and 1 μm for visible light and near-infrared light. The irradiation time of the laser light of each wavelength is as follows: ultraviolet light has an exposure time of 100 s / time and the number of irradiations is 4, visible light has an exposure time of 60 s / time and the number of irradiations is 4, and near-infrared light is exposed. The time is 60 s / time and the number of irradiations is 6 times.

The laser beam illuminates the sample at the spot of the measurement point, with or without damage marks. When performing Raman spectroscopic analysis using this laser Raman microspectroscopy, the secondary light emitted from the measurement point enters the main spectroscope after passing through the aperture, polarizer, depolarizing plate, etc. The intensity spectrum for each wavelength of the secondary light is measured.

(Damage evaluation method) For each sample, the presence or absence of damage marks due to laser irradiation was confirmed using an optical microscope. The presence or absence of damage marks can be sufficiently confirmed visually from observation with an optical microscope or a photographic image with an optical microscope. However, if the judgment is more objective, the above photographic image is converted into a black-and-white binary image by setting the brightness threshold value to, for example, 140 with image processing software such as JTrim, and the irradiation spot is the center. A square region having a side of, for example, 5 μm is cut out, and the ratio of the number of black pixels contained in the square region to the total number of white and black pixels is calculated, and whether or not the ratio changes before and after laser irradiation. You should check. If no damage marks are found, it is evaluated as undamaged. It was also confirmed whether there was a difference in the Raman spectroscopic spectrum before and after the laser irradiation.

(Results of Laser Resistance Test) FIG. 5 compares the images of the sample surface taken by an optical microscope before and after the laser irradiation for the sample # 2 (WC). FIG. 6 is a diagram comparing the captured images of sample # 5 (WC) in the same manner. FIG. 7 is a similar diagram for sample # 7 (WC).
Sample # 2 (WC) has no damage marks for laser light of any wavelength. Therefore, it is evaluated that there is no damage. Although not shown, there is no difference in the Raman spectrum.
Sample # 5 (WC) has no damage marks in ultraviolet light and near-infrared light, but in the case of visible light laser light, damage marks are found only when the laser intensity is 1.4 × 10 ³ kW / cm ^2. It is recognized (however, the difference in Raman spectrum is not clear). Therefore, damage threshold for visible laser light, is less than ^{1.4 × 10 3 kW / cm 2} , and greater than 765kW / cm ^2.
In sample # 7 (WC), no damage marks are observed in ultraviolet light and near infrared light, but in the visible light laser light, damage marks are observed when the laser intensity is 765 kW / cm ² or more (in the Raman spectrum). There is a difference). Therefore, damage threshold for visible laser light, with less than 765kW / cm ^2, and greater than 380 kW / cm ^2.

Similarly, for other samples, the presence or absence of damage marks due to laser irradiation was examined to determine the damage threshold. The three columns on the right column of Table 3 are arranged. Sample # 5 (WC) and sample # 6 (WC) on which the carbon film of the present invention is formed have an ultraviolet damage threshold value of more than 80 kW / cm ² and a visible damage threshold value of 765 kW / cm ² . The condition that the value exceeds 1400 kW / cm ² and the damage threshold value in the near infrared region is larger than 1600 kW / cm ² is satisfied. These are the conditions for the carbon film formed on the WC cemented carbide substrate. By the way, when a carbon film (# 5 or # 6) is formed on a diamond substrate, the damage threshold becomes higher, and the damage threshold when irradiating with visible light laser light becomes larger than 1400 kW / cm ² , and it is ultraviolet. No damage marks are generated by laser irradiation in either visible or near infrared light. That is, the film on the diamond substrate has higher laser resistance than the film on the cemented carbide substrate. This is because the WC-based superhard substrate has a high reflectance, so the film is damaged by the superimposed light of the incident laser light and the reflected laser light reflected at the interface between the film and the substrate, but the diamond substrate has the reflectance. This is because the film is mainly damaged only by the incident laser light because of its small size.

(Optical characteristics of carbon film) As a preparation for discussing the difference in damage form as described above, the measurement of the refractive index and extinction coefficient of the carbon film will be described. FIG. (12A) is a graph showing the refractive index and extinction coefficient as a function of wavelength for the carbon films of samples # 2 (WC) and # 3 (WC) on which the hydrogen-free carbon film was formed. .. FIG. (12B) is a similar graph of the carbon films of Samples # 5 (WC), # 7 (WC) and # 10 (WC) on which the hydrogen-containing carbon film was formed. Here, the refractive index and the extinction coefficient were calculated by fitting the reflectance measured by a spectral reflectance measuring device (USPM-RU-2, Olympus) with the optical thin film analysis software FilmStar. At this time, the film thickness of the carbon film (about 500 nm) is also calculated at the same time.

(Differences in damage due to film type, film thickness, and laser wavelength) When laser light is vertically incident on the carbon film formed on the substrate, it is reflected or reflected at the interface between the substrate and the carbon film and the interface between the carbon film and the air. The transmitted laser beam is superposed on the incident laser beam to generate a stationary wave electric field. FIG. 13 shows an example of such a standing wave electric field calculated by a one-dimensional model using thin film design software (EF calc). FIG. (13A) shows the spatial distribution of the square of the electric field E generated when the ultraviolet laser beam is incident on the sample # 10 (WC). The electric field is standardized by the amplitude E ₀ of the electric field of the incident laser light. Similarly, the case where the visible light laser light is incident is shown in FIG. (13B), and the case where the near infrared light laser light is also incident is shown in FIG. (13C). The maximum value of the square of the electric field in the carbon film standardized in the above sense is 1.3 in the ultraviolet, 0.6 in the visible, and 0.6 in the near infrared, which is the highest in the ultraviolet. As shown in Table 3, when the laser intensity is 10 kW / cm ² , damage marks are seen on the carbon film of sample # 10 (WC) only when irradiated with ultraviolet rays, and when irradiated with visible and near infrared rays. No damage marks are seen. It is considered that this is because the thermal fracture of the carbon film is related to the magnitude of the electric field. It is also considered that damage is likely to occur when the square of the electric field takes a large value near the interface between the carbon film and air, which are easily damaged.

The laser damage threshold shown in Table 3 must be carefully applied as it is when the base material is other than WC-based cemented carbide or when the film thickness of the carbon film is significantly different from about 500 nm. .. However, if the refractive index and extinction coefficient of the base material and the film thickness, refractive index and extinction coefficient of the carbon film are known, the standing wave electric field is calculated by the above method, and the space of the squared value of the calculated electric field is calculated. Based on the distribution, the damage threshold when a laser beam of each wavelength is incident can be estimated.

(Change in Raman spectrum due to laser damage) FIG. (14A) shows Raman after irradiating the hydrogen-containing carbon film of sample # 10 (WC) with the visible light laser light having a wavelength of 532 nm at each of the six levels of laser intensity. It is a graph which shows the Raman spectrum by spectroscopic analysis. FIG. (14B) is an enlarged graph in which a part of the graph is translated in the y-axis direction and superposed so that the difference in shape of the six Raman spectra can be easily understood. Observation with an optical microscope confirms damage marks with a laser intensity of 130 kW / cm ² or more. Looking at the Raman spectrum, changes can be seen in the Raman spectrum when the laser intensity is 130 kW / cm ² or more. The laser damage, the width of the G peak in the vicinity of Raman shift 1360 cm ^-1 D peak and 1554cm around ^-1 spread and change the D peak is significantly higher seen. In the case of irradiation with a laser intensity of 1 kW / cm ² , the noise level of the Raman spectrum is high and analysis is difficult.

FIG. (15A) shows Raman spectroscopic analysis after irradiating the hydrogen-containing carbon film of sample # 5 (WC) with the visible light laser light having a wavelength of 532 nm at the laser intensity of the upper three steps out of the six steps. It is a graph which shows the Raman spectrum. FIG. (15B) is an enlarged graph in which a part of the graph is translated in the y-axis direction and superposed so that the difference in shape of the three Raman spectra can be easily understood. Observation with an optical microscope confirms damage marks with a laser intensity of 1.4 x 10 ³ kW / cm ² or more. However, even when damage marks are confirmed, no significant change is observed in the Raman spectrum including the vicinity of the D peak and the vicinity of the G peak.

<5. Raman spectroscopic analysis>
(Motivation) Raman spectroscopic analysis was performed to find out further optical properties that distinguish the carbon film according to the present invention from the carbon film according to the comparative example.
(Sample Preparation) The sample (# 1 (Dia) to # 10 (Dia)) to be analyzed by Raman is placed on the <100> surface of the diamond substrate (diamond thickness 10 μm) which is the base material, and the above T-FAD apparatus. Therefore, a carbon film was formed with a target thickness of 500 nm. The atmosphere (gas type, gas flow rate, process pressure) and substrate bias, which are the film forming conditions, are as shown in the table of FIG. Further, the diamond substrate itself on which the carbon film is not formed is represented by sample # 0 (Dia).

(Equipment used and laser intensity) Using the same laser Raman microspectrophotometer (NRS-7100, Nippon Spectroscopy Co., Ltd.) used in the above laser resistance test, visible light CW laser light with a wavelength of 532 nm, or The sample was irradiated with a near-infrared CW laser beam having a wavelength of 785 nm, and Raman spectroscopic analysis was performed. The exposure time, the number of irradiations, and the spot diameter at each laser wavelength are the same as in the above laser resistance test. The dimmer was set to OD 0.6 for visible light and OD 0.3 for near infrared light. Therefore, as can be seen from Table 2, the laser intensities used are 380 kW / cm ² for visible light and 900 kW / cm ² for near infrared light. The resolution of the Raman spectrum is 0.2 cm ^-1 .

(Visible Raman analysis and ND peak) FIG. (8A) shows the Raman spectrum of each sample when the above visible light laser beam is incident. In the Raman spectrum of sample # 0 (Dia), which is the diamond substrate itself, an ND peak peculiar to diamond appears near 1332 cm ^-1 (ND means Natural Diamond). In the diamond film made of polycrystalline diamond, an ND peak is observed regardless of whether it is N-dopped CVD, Colorless CVD, BL-PCD, or High pressure Ib.
Samples # 2 (Dia) and # 3 (Dia) are both hydrogen-free carbon films. An ND peak is observed in sample # 2 (Dia), but no ND peak is observed in sample # 3 (Dia). This is because the former is ta-C rich in sp ³ bonds, while the latter is a-C poor in sp ³ bonds. No ND peak is also observed in samples # 5 (Dia) and # 8 (Dia), which are hydrogen-containing carbon films.

(Near-infrared Raman analysis and ND peak) FIG. (8B) shows the Raman spectrum of the carbon film of each sample when the near-infrared laser beam is incident. The Raman spectra of samples # 0 (Dia), # 2 (Dia), # 5 (Dia), and # 8 (Dia) all show a diamond-specific ND peak near 1330 cm ^-1 . However, no ND peak was observed in sample # 3 (Dia), which is a-C with poor sp ³ binding, even when confirmed by magnifying 140 times. Table 3 also summarizes the presence or absence of ND peaks in visible and near-infrared Raman analysis for other samples.

(Differentiation between hydrogen-free and hydrogen-containing carbon film) From the above, generally, if an ND peak is not observed in the visible Raman analysis of the target film and an ND peak is observed in the near-infrared Raman analysis of the target film, the target is targeted. It can be seen that the membrane is neither ta-C nor a-C. Therefore, the target film is a hydrogen-containing carbon film. Here, by further paying attention to the intensity ratios I _D / _IG and G peak position in the visible Raman analysis, it is possible to determine whether or not the target film is the carbon film according to the present invention. The method will be described.

Generally the visible Raman spectrum (the intensity ratio I _D / I _G and G peak position) carbon film, a DLC-specific, and D peak of the Raman shift around 1360 cm-1, also a G peak around 1580 cm-1, but appear. The intensities (heights) and positions of these peaks were determined for each sample by fitting the graph of the Raman spectrum by superimposing a linear or quadratic function representing the background and two Gaussian functions. .. Based on it, to calculate the ratio I _D / I _G peak intensity I _D and I _G, those described in conjunction with the position of the G peak (G peak position) is Table 3. Table 3 shows the values for each sample (# 1 (Dia) to # 10 (Dia)) formed on the diamond substrate. Table 1 shows the values obtained by similarly performing Raman spectroscopic analysis on the samples (# 1 to # 10) formed on the n-type Si substrate.

Table sample for the 1 and Table 3, the hydrogen content of (at.%) Represented by the horizontal axis, plots the intensity ratio I _D / I _G ordinate is a scatter diagram shown in FIG. (17A), also hydrogen The scatter diagram shown in FIG. (17B) is plotted with the content on the horizontal axis and the G peak position. White circles represent samples formed on a diamond substrate, and black circles represent samples formed on a Si substrate. Figures (17A), for the hydrogen-containing carbon film it can be seen that the hydrogen content increases the intensity ratio I _D / I _G increases. Also, more of the carbon film formed on the diamond substrate, a carbon film deposited on the Si substrate, a large intensity ratio I _D / I _G. From FIG. 17B, with respect to the hydrogen-containing carbon film, as the hydrogen content increases, the G peak position once decreases, and the hydrogen content becomes 10 to 15 at. It can be seen that it increases again from around%. It can also be seen that the G peak position of the hydrogen-free carbon film increases as the sp ³ composition ratio increases.

The samples in Tables 1 and 3 are plotted with the intensity ratio I _D / _IG on the vertical axis and the G peak position on the horizontal axis, which is a scatter diagram shown in FIG. (18A). White circles represent samples formed on a diamond substrate, and black circles represent samples formed on a Si substrate. The hydrogen-containing carbon films according to the present invention are # 5 and # 6. Intensity ratio I _D / I _G of the hydrogen-containing carbon film increases as the hydrogen content increases, also tends to become larger as the sp ³ configuration ratio decreases. Further, the G peak position of the hydrogen-containing carbon film having a hydrogen content in the range of 5 to 20% tends to increase as the sp ³ composition ratio increases. Further, the carbon film according to the present invention, a film was formed on the diamond substrate, as compared with the film formed on the Si substrate, the intensity ratio I _D / I _G is greater as 0.05 to 0.2 , G peak position is as small as 2-5 cm ^-1 . Therefore, the intensity ratio I _D / I _G of the target film formed on the diamond substrate is 0.5 or less, and if G peak position is 1545 cm ^-1 or more, the hydrogen content of the target layer is approximately 10 % Or less, and the sp ³ composition ratio is about 40 at. It turns out that it is more than%. In addition, it is the intensity ratio I _D / I _G of the target film is 0.2 or more, and if G peak position is 1570 cm ^-1 or less, the hydrogen content of the target film is at about 5% or more, and The sp ³ composition ratio is about 60 at. It turns out that it is less than%. Therefore, it can be determined that such a target film is a carbon film according to the present invention.

Furthermore, the intensity ratio I _D / I _G of the target film formed on the diamond substrate is not less than 0.5, and if the G peak position is 1548Cm ^-1 or more, the hydrogen content of the target film is It is about 10% or less, and the sp ³ composition ratio is about 45 at. It turns out that it is more than%. In addition, the intensity ratio I _D / I _G of the target film is not less than 0.3, and if the G peak position is 1555Cm ^-1 or less, the hydrogen content of the target layer is located at about 5% or more And the sp ³ composition ratio is about 55 at. It turns out that it is less than%. Therefore, it can be determined that the target film is the carbon film of the present invention.

For reference, some of the DLC film by the present inventors deposited the WC-based cemented carbide substrate and diamond on the substrate, a plot of G peak positions and intensity ratios I _D / I _G shown in FIG. (18B). The number "50" in the membrane symbol "ta-C: H (50)" means that the nanoindentation hardness of the membrane is 50 GPa. In that the G peak position changes to "U-shaped" with respect to the intensity ratio I _D / I _G, which is a graph of similar shape and FIG. (18A). The film formed on the diamond substrate has a strength ratio I _D / I _G of about 0.05 to 0.2 larger than that of the film formed on the WC-based cemented carbide substrate.

<6. Mechanical and optical properties of carbon film>
(Motivation) In order to further clarify the mechanical and optical properties of the carbon film according to the present invention, various measurements and experimental data were organized.
(Classification of Carbon Films by Optical Constant) FIG. 10 shows a rough optical classification of carbon films based on the refractive index and the extinction coefficient proposed by the present inventor.

(Dependence on Gas Flow Rate and Bias Voltage at Intensity Ratios I _D / I _G and G Peak Positions) Fig. 16 shows the intensity ratios I _D / I _G and G peak positions of the carbon film by visible laser Raman spectroscopy. It is explanatory drawing which shows the dependence on a gas flow rate and a bias voltage at the time of film formation. The filled points show the data of the carbon film formed on the WC-based cemented carbide substrate, and the white points show the data of the carbon film formed on the n-type Si substrate. The intensity ratio I _D / _IG and G peak positions are indicators of the sp ³ composition ratio.
The higher the gas flow rate, the larger the intensity ratio I _D / I _G tends to be. The gas species, in descending order of intensity ratio _{I D / I G, C 2} H 4, a C ₂ H _2, H _2. This is because the sp ³ composition ratio of the membrane decreases as the C ⁺ ions lose energy due to collision with the gas. Further, the larger the gas flow rate, the smaller the G peak position tends to be. The gas types are C ₂ H ₄ , C ₂ H ₂ , and H ₂ in ascending order of G peak position. This is also because the sp ³ composition ratio of the film decreases as the C ⁺ ions lose energy due to collision with the gas.
The larger the absolute value of the negative bias voltage, the larger the intensity ratio I _D / I _G tends to be. The gas species, in descending order of intensity ratio _{I D / I G, H 2} , C 2 H 2, C 2 H 4, is without gas. This is because, in the absence of gas, C ⁺ ions become excessive in energy due to acceleration due to the bias voltage, making it difficult to form sp ³ bonds, and the sp of the membrane is such that C ⁺ ions lose energy due to collision with gas. ^{3 This is because the} composition ratio increases. Further, the larger the absolute value of the negative bias voltage, the smaller the G peak position tends to be. The gas types are C ₂ H ₄ , C ₂ H ₂ , H ₂ , and no gas in order from the one with the smallest G peak position. This also reflects the difference in sp ³ composition ratio as described above.

The present invention is not limited to the above-described embodiment, and it is said that various modifications, design changes, other examples, etc. within the range not deviating from the technical idea of the present invention are included in the technical scope. Not to mention.

Since the hydrogen-containing carbon film according to the present invention has an extremely high start temperature of hydrogen gas desorption of 800 ° C. or higher, it has high heat resistance, and is a highly heat-resistant protective film for covering articles such as cutting tools and lenses. It can be suitably used for applications such as a highly heat-resistant mold release film that covers the surface of a mold such as a molding mold, and a heat-resistant self-standing film separated from a base material. Therefore, the carbon film according to the present invention has a wide range of industrial applicability.

1 TDS analyzer 10 Sample 11 Thermocouple 12 Sample stand Center 13 Graphite sample stand 14 Quartz window 15 Quite disk 16 Gold elliptical mirror 17 Infrared lamp 18 Pirani gauge 19 Ionization vacuum gauge MV, RV, LV valve TMP, RP pump QMS mass filter type Gas Analyzer GLC Graphite-like Carbon PLC Polymer-like Carbon Graphite _O Graphite (α-graphite)
Graphite _ex graphite (β-graphite)

Claims (12)

Protects at least part of the surface of the substrate,
Carbon is the main component, and 5 at. It contains more than% hydrogen and has both carbon having an sp ² hybrid orbital component and carbon having an sp ³ hybrid orbital component.
A carbon film characterized in that desorption of contained hydrogen occurs at 800 ° C. or higher when heated in a vacuum. The carbon film according to claim 1, wherein desorption of hydrocarbons does not occur at 1000 ° C. or lower when heated in a vacuum. The carbon according to claim 1 or 2, wherein the base material is diamond, or the base material is a base material having a diamond film formed on the surface thereof, and protects at least a part of the surface of the base material. film. The carbon film according to any one of claims 1 to 3, wherein the refractive index with respect to light having a wavelength of 546 nm is 2.4 or more and 2.7 or less, and the extinction coefficient is 0.1 or more and 0.2 or less. The film density is 2.6 g / cm ³ or more and less than 3.1 g / cm ³ and
The carbon according to any one of claims 1 to 4, wherein the composition ratio sp ³ / (sp ³ + sp ² ) of carbon having an sp ² hybrid orbital component and carbon having an sp ³ hybrid orbital component is 40% or more and less than 60%. film. A method for determining whether or not the hydrogen-containing amorphous carbon film formed on the surface of a substrate having a refractive index of 0.1 or more and an extinction coefficient of 1.0 or more is the carbon film according to claim 1. The hydrogen-containing amorphous carbon film is
In CW (continuous wave) laser irradiation of ultraviolet light with a wavelength of 324 nm, the irradiation intensity was 80 kW / cm ² and it was not damaged.
In the CW laser irradiation of near-infrared light with a wavelength of 785 nm, the irradiation intensity was 1.6 × 10 ³ kW / cm ² and was not damaged.
In CW laser beam irradiation with visible light having a wavelength of 532 nm, without being damaged in irradiation intensity 765kW / cm ^2, damaged by ^{1.4 × 10 3 kW / cm 2} ,
A discrimination method characterized by having a step to confirm that. A method for determining whether or not the hydrogen-containing amorphous carbon film formed on the surface of diamond is the carbon film according to claim 1.
For the hydrogen-containing amorphous carbon film,
When Raman spectroscopy was performed with visible light laser light with an irradiant intensity of 3.8 × 10 ² kW / cm ² , the spectrum of diamond with a Raman shift of 1329 to 1338 cm ^-1 was not detected.
When Raman spectroscopy was performed with near-infrared laser light with an irradiance intensity of 8.9 × 10 ² kW / cm ² , a diamond spectrum with a Raman shift of 1329 to 1338 cm ^-1 was detected.
When performing Raman spectroscopy in the visible light laser beam, in DLC spectrum intensity ratio I _D / I _G of the D and G-peaks is 0.2 or more and 0.5 or less, and is G peak position 1545 cm ^{- 1} or more and 1570 cm ^-1 or less,
A discrimination method characterized by having a step to confirm that. Select from the group consisting of nitrogen, oxygen, boron, argon, silicon, phosphorus, sulfur, antimony, selenium, tellurium, fluorine, chlorine, astatine, transition metal elements, aluminum, zinc, indium, tin, antimony, lead and bismuth. The carbon film according to any one of claims 1 to 5, which contains one or more of the elements. The carbon film according to any one of claims 1 to 5 and 8, wherein the base material is a tool, a mold, a cutting tool, a sliding member, or an ornament. The carbon film according to any one of claims 1 to 5 and 8, wherein the base material is an optical component. An article characterized in that at least a part of the surface is protected by the carbon film according to claim 9 or 10. The carbon film according to claim 1 or 2, which is a self-supporting film separated from the base material.