JP2022088909A - Slide contact member, conductive high hardness protective film and method for manufacturing slide contact member - Google Patents

Abstract

To provide: a slide contact member capable of suppressing transfer when used for a contact member while improving wear resistance and used even in a high temperature environment; a conductive high hardness protective film provided in such a slide contact member, or a contact member; and a method for manufacturing the slide contact members thereof.SOLUTION: A slide contact member includes a conductive high hardness protective film 20 consisting of a carbon based film having a surface resistance value of less than 1×103 Ω and a surface hardness of 10 GPa or more on the surface of a base material 10. Such a slide contact member is obtained by depositing a carbon film having conductive carbon fine particles dispersed on the surface of the base material by controlling the ratio of carbon ions to carbon fine particles by the deflection action of an electromagnetic field when generating carbon plasma by arc discharge to provide a conductive high hardness protective film consisting of a carbon based film having a surface resistance value of less than 1×103 Ω and a surface hardness of 10 GPa or more on the surface of the base material.SELECTED DRAWING: Figure 1

Description

The present invention relates to a sliding contact member capable of electrically conducting electrical conduction to a semiconductor, an electronic component, various electronic devices and mechanical parts configured by using the semiconductor, a conductive high hardness protective film, and a method for manufacturing the sliding contact member.

The semiconductor manufacturing process includes a wafer processing process called a "pre-process" and an assembly process called a "post-process". The pre-process refers to the process of manufacturing a large number of semiconductor chips on the surface of the wafer, and the post-process is to cut out the semiconductor chips from the wafer and mount the semiconductor integrated circuit (LSI, VLSI, ULSI, etc.) as the final product (package). The process of obtaining parts. In the pre-process, a wafer inspection using a probe called a probe pin is performed, and the defective semiconductor chip is eliminated so as not to be sent to the post-process. Further, in the post-process, the mounted parts are inspected using the probe pins (also referred to as “package inspection” or the like), and defective products are eliminated before the product is shipped.

For example, in wafer inspection, a probe card corresponding to the inspection target is used. A probe pin is attached to the probe card. By pressing the probe pin against the semiconductor chip by spring pressure, the probe pin and the electronic terminal material of the semiconductor chip are brought into contact with each other, and an electrical characteristic test such as a continuity test or an operation test is performed. Also in the mounted component inspection, a predetermined electrical property test is performed on the semiconductor package. By such an electrical characteristic test, a non-defective product or a defective product is determined, and the defective product is excluded.

Hundreds to thousands or even tens of thousands of such semiconductor integrated circuits are produced in one line or factory per day. Since the above electrical property test is basically an 100% inspection, probe pins are pressed against the electronic terminal material according to the number of products produced. Therefore, wear resistance is required for the contact portion of the probe pin with the terminal material.

Further, usually, an oxide film is formed on the surface of the electronic terminal material. On the other hand, the contact portion at the tip of the probe pin has a predetermined shape according to the inspection target. When the probe pin is pressed against the probe pin during inspection, the oxide film on the surface of the electronic terminal material is broken and the fresh electronic terminal material inside the probe pin comes into contact with the probe pin. As a result, the electrical characteristics of the inspection target are accurately evaluated. However, if a soft material such as solder is used as the electronic terminal material, these soft materials may adhere to the tip of the probe pin. Hereinafter, this phenomenon is referred to as "transcription". When transfer occurs, the sharpness of the contact portion of the probe pin is impaired, and it becomes difficult to break the oxide film on the surface of the electronic terminal material to be inspected next.

In order to prevent such a problem, the worker performing the above electrical property test regularly performs maintenance work such as polishing the contact portion of the probe pin with a metal brush or the like. However, in order to perform this maintenance work, it is necessary to temporarily stop the inspection device. On the other hand, if this maintenance work is not performed, the probe pin is pressed against the electronic terminal material with a contact pressure higher than the specified value, and the semiconductor chip to be inspected or the semiconductor package is damaged, or accurate measurement can be performed. However, a judgment error may occur, such as judging a non-defective product as a defective product. As a result, the yield may deteriorate and the productivity may be significantly reduced.

The cause of the transfer is wear of the contact portion. When the surface roughness of the contact portion increases with wear, a soft electronic terminal material such as solder easily adheres to the contact portion. Further, the contact portion of the probe pin is plated with a precious metal such as gold, a gold alloy, or rhodium in order to improve conductivity. Solder is an alloy whose main components are tin and lead, but it has a strong chemical bond with precious metals and easily adheres to the contact points.

Therefore, when plating the probe pin with a noble metal, transfer is performed by co-depositing resin particles such as graphite fine particles and polytetrafluoroethylene (PTFE) particles with particles that do not easily form a chemical bond with solder or the like. It is made less likely to occur. However, when these methods are adopted, there is a problem that the contact resistance of the probe pin becomes high. In general, resin particles often have low heat resistance. For example, the burn-in test is performed at a high temperature such as 150 ° C. Therefore, when it contains resin particles having low heat resistance, it cannot be used for the probe pin used in the burn-in test. Further, since the PTFE particles as disclosed in Patent Document 2 are soft, the wear resistance cannot be sufficiently improved by these methods.

On the other hand, in order to improve transferability and abrasion resistance, for example, a method of providing a thin film made of a carbon-based material such as graphite or diamond-like carbon (DLC) on the surface of the probe pin can be considered. Carbon materials such as graphite and diamond-like carbon have low chemical reactivity with solder, so transfer is unlikely to occur. In particular, DLC has a high hardness and a low coefficient of friction, and is therefore often used as a protective film for a sliding contact portion. However, DLC has high resistance and is not suitable as a protective film for probe pins.

Patent No. 4044926 Patent No. 3551411

The present invention has been made in view of the above problems, and is a sliding contact member that can be used even in a high temperature environment by suppressing transfer when used as a contact member while improving wear resistance. It is an object of the present invention to provide a conductive high hardness protective film provided on a sliding contact member and a method for manufacturing these sliding contact members.

In order to achieve the above object, the sliding contact member according to the present invention has a high conductivity made of a carbon-based coating having a surface resistance value of less than 1 × 10 ³ Ω and a surface hardness of 10 GPa or more on the surface of the base material. It is characterized by having a hardness protective film.

In the sliding contact member according to the present invention, in the carbon-based coating, conductive fine particles are dispersed in a carbon coating containing carbon having a sp2 structure and carbon having a sp3 structure, and when the surface of the carbon-based coating is observed. It is preferable to contain conductive fine particles in an area ratio of 1% or more and 80% or less.

In the sliding contact member according to the present invention, the carbon-based coating has H, N, F, Al, Si, Cr, Ag, Ti, Cu, Ni, W, Ta, Mo, Zr, B, Fe as additive elements. , Pt, P, S, I, Mg, Zn and Ge may contain one or more elements selected from the group.

In the sliding contact member according to the present invention, the friction coefficient of the carbon-based coating is preferably 0.5 or less.

In the sliding contact member according to the present invention, the film thickness of the carbon-based coating is preferably 20 nm or more and 10 μm or less.

In the sliding contact member according to the present invention, it is preferable that the conductive high hardness protective film is provided at least on the surface of the terminal portion that is electrically and / or mechanically in contact with another member of the base material.

In order to achieve the above object, the conductive high hardness protective film according to the present invention is provided on the surface of a contact member that is electrically and / or mechanically in contact with another member, and its surface resistance value is 1 × 10 ³ . It is characterized by being composed of a carbon-based coating having a surface hardness of 10 GPa or more and smaller than Ω.

In order to achieve the above object, the method for manufacturing a sliding contact member according to the present invention is based on controlling the ratio of carbon ions and carbon fine particles by the deflection action of an electromagnetic field when carbon plasma is generated by arc discharge. A carbon film in which conductive carbon fine particles are dispersed is formed on the surface of the material, and the surface resistance value is smaller than 1 × 10 ³ Ω and the surface hardness is 10 GPa or more. It is characterized by providing a high hardness protective film.

According to the present invention, a sliding contact member that can be used even in a high temperature environment by suppressing transfer when used for a contact member while improving wear resistance, and a high conductive hardness provided in such a sliding contact member. It is possible to provide a method for manufacturing a protective film and a sliding contact member thereof.

(A) It is a figure which represented the cross section of the conductive high hardness film provided on the surface of a base material schematically. 6 is an SEM photograph (photographing magnification 500 times) showing the surface of the metal intermediate layer 30 when the metal intermediate layer 30 is provided on the surface of the base material. (A) SEM photograph showing the surface of the conductive high-hardness film of Example 1 (photographing magnification 2,000 times), (b) SEM photograph showing the surface of the conductive high-hardness film of Example 2 (photographing magnification 2,). 000 times), (c) SEM photograph (photographing magnification 2,000 times) showing the surface of the conductive high hardness coating of Example 3. 6 is an SEM photograph (photographing magnification 300 times) showing the surface of the conductive high hardness film of Comparative Example 1.

Hereinafter, a sliding contact member, a conductive high hardness protective coating, and a method for manufacturing the same will be described.

1. 1. Sliding contact member The sliding contact member according to the present invention refers to a member having a probability of being in contact with another member and being rubbed against the other member when in contact with the other member. The sliding contact member may be a member that is required to have continuity with another member, or may be a member that is not required to have continuity. For example, it may be a member that requires continuity with other members such as the contact member described below, or it may be used in a milling machine (milling machine) such as various drills, end mills, and milling cutters attached to electric drills and the like. It may be a member that is in direct contact with other members such as a mold and a wafer cassette, and is not required to have continuity. Further, it may be a sliding member that comes into contact with another member and is slid while moving relative to the other member. However, since the conductive high hardness protective film according to the present invention has a small surface resistance, it is preferable that the sliding contact member is not a member that requires insulation. Since the sliding contact member according to the present invention has the conductive high hardness protective film according to the present invention, the wear resistance is improved as compared with the one without the conductive high hardness protective film, while the low resistance value is maintained. can do. Therefore, when applied to a contact member having a terminal portion that electrically and / or mechanically contacts another member, the machine with the other member while maintaining good continuity between the contact member and the other member. It is possible to suppress wear and the like due to contact with the target. Examples of the contact member include a probe pin used in contact with an electrode or the like of an inspection target in a wafer inspection, a package inspection, or the like performed in a semiconductor manufacturing process. Hereinafter, the sliding contact member and the contact member according to the present invention will be described by taking a contact member as an example. The sliding contact member according to the present invention includes contact members such as probe pins, mechanical relay terminals, and motor rotation. It can be applied to various terminal members having terminal portions that are in electrical and mechanical contact with other members such as children, as well as the above-mentioned various tools and the like.

The configuration of the contact member is schematically shown in FIG. In the example shown in FIG. 1, the contact member 100 is provided with a conductive high hardness protective coating 20 on the surface of the base material 10, and a metal intermediate layer 30 is provided between the base material 10 and the conductive high hardness protective coating 20. Has been done. The metal intermediate layer 30 has an arbitrary layer structure in the present invention. Further, in the example shown in FIG. 1, the conductive high hardness protective coating 20 contains the conductive carbon fine particles 22 in the carbon coating 21 serving as the base layer. Further, the metal fine particles 31 precipitated in the metal intermediate layer 30 are present at the interface with the conductive high hardness protective film 20. Hereinafter, the base material 10, the conductive high hardness protective coating 20, and the metal intermediate layer 30 will be described in this order.

(1) Base material 10
The base material 10 of the contact member 100 may be made of, for example, various metals such as copper, iron, nickel, and aluminum, or various alloys such as copper alloys, iron alloys, nickel alloys, and aluminum alloys. However, the material of the base material 10 is not particularly limited as long as it is made of a material that can satisfy the electrical and mechanical properties required for the contact member 100. Further, the shape of the base material 10 is not particularly limited. For example, if the contact member 100 is a probe pin, the shape or the like required for the terminal portion of the probe pin may be satisfied, and the contact member 100 may have an arbitrary shape according to the intended use. When conductivity with other members is not required for the sliding contact member, the base material 10 of the sliding contact member may be a cemented carbide base material, a ceramic base material, in addition to the above-mentioned various metals or alloys thereof. It may be a resin base material or the like.

(2) Conductive high hardness protective film 20
Next, the conductive high hardness protective film 20 will be described. The conductive high hardness protective film 20 may be provided on the surface of the terminal portion (contact portion) of the contact member 100 (base material 10) and the like, and may be provided at a portion that is in direct contact with another member. If the conductive high hardness protective film 20 is provided at a portion that is in direct contact with another member, the effect of the present invention can be enjoyed. However, the conductive high hardness protective film 20 is not limited to such a portion, and may be provided on the entire terminal portion or may be provided on the entire surface of the contact member 100. By providing the conductive high hardness protective film 20, for example, even if a soft metal material such as solder is used for the electrode portion of the object to be inspected, carbon and solder are difficult to chemically bond and wear resistance. Since the properties can be improved, these transfers to the terminal portion can be prevented, and the maintenance frequency can be reduced. Further, since the surface resistance value is low, good conductivity can be maintained.

The conductive high hardness protective film 20 is a carbon-based material having a surface resistance value smaller than 1 × 10 ³ Ω, preferably 1 × 10 ² Ω or less, more preferably 1 × 10 Ω or less, and a surface hardness of 10 GPa or more. It consists of a coating. Here, graphite and diamond-like carbon (DLC) are known as carbon-based materials. Since graphite is conductive, when a thin film made of graphite is provided at a portion that is in direct contact with another member, it is possible to prevent an increase in resistance at the contact portion. However, since graphite is a soft material, the surface hardness is lower than 10 GPa, and the effect of improving the wear resistance of the contact portion can be obtained only slightly. On the other hand, the surface hardness of DLC is 10 GPa or more, and the effect of improving the wear resistance of the contact portion is high. However, the surface resistance value of DLC is 1 × 10 ³ Ω or more, and the resistance at the contact portion increases. Therefore, DLC is not suitable as a protective film for contact members. After diligent research by the present inventors, for example, it was found that a carbon-based film having a surface resistance value of less than 1 × 10 ³ Ω and a surface hardness of 10 GPa or more can be obtained by a method described later. Can be provided on the surface of the base material 10 as a conductive high hardness protective film 20 to suppress transfer and provide a contact member (and a sliding contact member) that can be used even in a high temperature environment while improving wear resistance. I found that. Hereinafter, preferred embodiments of the conductive high hardness protective coating 20 will be described.

As shown in FIG. 1, the conductive high hardness protective coating 20 is preferably a carbon-based coating in which conductive fine particles such as conductive carbon fine particles 22 are dispersed in a carbon coating 21 as a base layer. By using such a carbon-based coating, the surface resistance value can be smaller than 1 × 10 ^3Ω and the surface hardness can be 10 GPa or more, and the electrical characteristics and mechanical characteristics suitable for the protective coating of the contact member can be obtained. Can be realized.

The carbon film 21 preferably contains carbon having a sp2 structure and carbon having a sp3 structure. For example, an amorphous carbon film having a relatively high carbon content having a sp2 structure containing carbon having a sp2 structure and a carbon having a sp3 structure, or a tetrahedral carbon film having a relatively high carbon content in the sp3 structure. A so-called DLC is preferable, and a tetrahedral carbon film is particularly preferable. Further, the carbon film may or may not contain hydrogen. The carbon content ratio of the sp3 structure is "sp2 / (sp3 + sp3) × 100, but the number of carbon atoms of the sp2 structure when sp2 and sp3 are subjected to elemental analysis of the carbon film 21 by X-ray photoelectron spectroscopy (XPS method)". And the number of carbon atoms in the sp3 structure ”, if the carbon content of the sp3 structure is 20% or more and 90% or less, the surface resistance value shall be 1 × 10 ³ Ω or more and 1 × 10 ¹² Ω or less. It is possible to obtain a surface hardness of 10 Gpa or more.

Further, the carbon film 21 has H, N, F, Al, Si, Cr, Ag, Ti, Cu, Ni, W, Ta, Mo, Zr, B, Fe, Pt, P, S and I as additive elements. , Mg, Zn and Ge may contain one or more elements selected from the group. These elements can be contained in the DLC film when the DLC film is formed by the vacuum vapor deposition method.

Examples of the conductive fine particles include conductive carbon fine particles 22 such as graphite. Graphite has high conductivity. Therefore, by dispersing a predetermined amount of the conductive carbon fine particles 22 in the carbon film 21, it is possible to obtain the conductive high hardness protective film 20 having a surface resistance value smaller than 1 × 10 ³ Ω. Further, as the conductive fine particles, in addition to the conductive carbon fine particles 22, the metal intermediate layer 30 is formed when the conductive high hardness protective film 20 is provided on the base material 10 via the metal intermediate layer 30 as described later. Examples thereof include the metal fine particles 31 generated when the film is formed. Further, in the conductive high hardness protective coating 20 according to the present invention, when the surface of the conductive high hardness protective coating 20 is observed, conductive fine particles such as the conductive carbon fine particles 22 can be observed from the surface. At this time, the size of the conductive fine particles is such that the projected area (hereinafter referred to as “fine particle cross section”) of the conductive high hardness protective coating 20 when observed on the surface is 0.01 μm ² to 1 mm ² . preferable. It is preferable to uniformly disperse the conductive fine particles of such a size in the carbon film 21 in order to obtain desired electrical characteristics.

Further, the content ratio of the conductive fine particles in the conductive high hardness protective film 20 is 1% or more and 80% or less in terms of area ratio when the surface of the conductive high hardness protective film 20 is observed by a scanning electron microscope. It is preferable to have. More specifically, an SEM photograph of the surface of the conductive high-hardness protective film 20 taken with a scanning electron microscope (for example, JSM-6510A manufactured by Nippon Denshi Co., Ltd.) at a photographing magnification of 2,000 times. Was analyzed using WinROOF image processing software (WinROOF 2018 Standard version manufactured by Mitani Shoji Co., Ltd.), and the area occupied by the conductive fine particles observed on the surface with respect to the surface surface of the conductive high hardness protective film in the observation area. (However, the sum of the areas corresponding to the cross-sectional areas of the conductive fine particles in the horizontal plane (that is, the sum of the projected areas of the particles)) ((the area of the conductive carbon fine particles / the area of the conductive high hardness protective film) × 100 ) Can be used as the content ratio of the conductive fine particles in the conductive high hardness protective film 20.

As the content of the conductive carbon fine particles 22 in the carbon film 21 increases, the surface resistance value of the conductive high hardness protective film 20 decreases. Since the surface resistance value of the carbon film 21 is 1 × 10 ³ Ω or more and 1 × 10 ¹² Ω or less, if the content of the conductive fine particles such as the conductive carbon fine particles 22 becomes too small, the conductive high hardness protective film is concerned. It becomes difficult to make the surface resistance value of 20 smaller than 1 × 10 ³ Ω. On the other hand, the hardness of the conductive carbon fine particles 22 is low. Therefore, if the content of the conductive carbon fine particles 22 in the carbon film 21 becomes too large, the surface hardness of the conductive high hardness protective film 20 becomes less than 10 GPa, and the effect of improving the wear resistance of the contact member is obtained. Will be difficult. From this point of view, the content ratio of the conductive fine particles in the conductive high hardness protective film 20 is preferably 1% or more and 80% or less, and more preferably 3% or more and 70% or less in terms of area ratio as described above. It is preferable, and it is more preferably 5% or more and 60% or less. When the content ratio of the conductive fine particles in the conductive high hardness protective film 20 is 1% or more and 80% or less in terms of area ratio, the surface hardness is 10 GPa or more, for example, when the content ratio is 13%. The surface hardness has achieved 50 GPa or more. If the surface hardness of the conductive high hardness protective film 20 is 10 GPa or more, it is sufficient to improve the wear resistance of the contact member, but the surface hardness is also high when used as the above-mentioned sliding contact member such as a cutting tool. If it is 10 GPa or more, the effect of improving the wear resistance can be obtained. For example, if it is 50 GPa or more, a sufficient effect for improving the wear resistance can be obtained.

Further, the film thickness of the conductive high hardness protective film 20 is preferably 20 nm or more and 10 μm or less. If the film thickness is too small, it becomes difficult to contain the conductive carbon fine particles 22 in the carbon film 21 in a desired amount. That is, it may be difficult to make the content of the conductive carbon fine particles 22 1% or more in the above area ratio. At the same time, the surface resistance value of the conductive high hardness protective film 20 becomes high, and it becomes difficult to make it smaller than 1 × 10 ³ Ω. On the other hand, if the film thickness is too thick, the productivity of the conductive high hardness protective film 20 deteriorates. From these viewpoints, the film thickness of the conductive high hardness protective film 20 is more preferably 50 nm or more and 5 μm or less, and further preferably 100 nm or more and 2 μm or less.

Further, the friction coefficient of the conductive high hardness protective film is preferably 0.4 or less, and more preferably 0.3 or less. As described above, when graphite is dispersed in the carbon film 21 as the conductive carbon fine particles 22, the friction coefficient of graphite is low, so that the probability that the friction coefficient becomes larger than 0.4 is low.

Further, it is preferable that the surface roughness (Ra) / film thickness ratio of the conductive high hardness protective film 20 is 2 times or less. When the conductive carbon fine particles 22 are dispersed in the carbon film 21, the conductive carbon fine particles 22 protrude from the surface of the carbon film 21 during the film formation of the conductive high hardness protective film 20, and the surface roughness becomes rough. It may get rough. If the surface roughness (Ra) / film film ratio exceeds 2 times, the transfer may easily occur when the contact portion of the contact member 100 is electrically and mechanically brought into contact with another member. Therefore, it is not preferable. The conductive carbon fine particles 22 are made of soft particles such as graphite. Therefore, it is easy to keep the surface roughness within the above range by polishing the surface of the conductive high hardness protective film 20 after the film formation.

(3) Metal intermediate layer 30
The metal intermediate layer 30 is a layer made of a metal or a metal compound having good chemical adhesion to both the base material 10 and the conductive high hardness protective coating 20, and can be provided as needed. Examples of the metal having good chemical adhesion to both the base material 10 and the conductive high hardness protective film 20 include Fe, Cr, Ti and the like. By providing a layer made of these metals and / or these and a metal compound such as N, O, C as a metal intermediate layer 30 between the base material 10 and the conductive high hardness protective film 20, the base material 10 can be used. It is possible to make good adhesion between each of the materials listed above and carbon, which is a constituent material of the conductive high hardness protective film 20. However, when the adhesion between the base material 10 and the conductive high hardness protective coating 20 is good, the conductive high hardness protective coating 20 may be provided directly on the surface of the base material 10 without providing the metal intermediate layer 30. can.

The metal intermediate layer 30 can be formed on the surface of the base material 10 by, for example, a vacuum vapor deposition method as described later. While the metal intermediate layer is formed by the vacuum vapor deposition method, metal fine particles 31 are generated in addition to the metal ions, and the metal fine particles 31 adhere to the film forming surface of the metal intermediate layer 30. Since the metal fine particles 31 have conductivity, when the conductive high hardness protective film 20 is provided on the surface of the base material 10 via the metal intermediate layer 30, as shown in FIG. 1, the metal fine particles 31 are contained in the carbon film 21. Since a part of the film is taken in, the surface resistance value of the conductive high hardness protective film 20 is lowered by the mutual contact between the conductive carbon fine particles 22 in the carbon film 21 and the metal fine particles 31, and the conductivity is further improved.

2. 2. Method for Manufacturing Sliding Contact Member and Contact Member Next, a method for manufacturing the sliding contact member and contact member 100 according to the present invention will be described. Here, as the sliding contact member, the contact member 100 schematically shown in FIG. 1 will be described as an example. When the contact member 100 generates carbon plasma by arc discharge, the carbon film 21 in which the conductive carbon fine particles 22 are dispersed on the surface of the base material 10 by controlling the ratio of carbon ions and carbon fine particles by deflection due to an electromagnetic field. Is characterized in that a conductive high hardness protective film 20 made of a carbon-based film having a surface resistance value of less than 1 × 10 ³ Ω and a surface hardness of 10 GPa or more is provided on the surface of the base material. Here, after the metal intermediate layer 30 is formed on the surface of the base material 10, the conductive high hardness protective film 20 may be formed.

(1) Method for forming a film of the conductive high hardness protective film 20 The conductive high hardness protective film 20 can be formed on the surface of the base material 10 by a vacuum vapor deposition method. As the vacuum vapor deposition method, for example, a cathode arc method, a sputtering method, an electron beam method, or the like can be adopted. In particular, when forming the conductive high hardness protective film 20 according to the present invention, it is preferable to adopt the cathode arc method. For example, by using a carbon electrode as a cathode electrode in a vacuum and causing an arc discharge, carbon plasma is generated to generate carbon ions and carbon fine particles, and the carbon ions are radiated to the base material 10 side. Carbon fine particles can also be attached to the base material 10 side while being deposited on the material 10. By this method, a carbon film 21 containing the conductive carbon fine particles 22 can be formed on the base material 10.

In the cathode arc method, an arc discharge is generally generated by passing a high current under a low voltage. If the carbon electrode is used as the cathode electrode as described above, carbon ions can be emitted from the carbon electrode with the arc discharge. In addition, carbon fine particles are also released from the carbon electrode due to heat generated by the arc discharge. For example, the DLC film is also formed by the cathode arc method. When carbon fine particles are mixed in the DLC film, the carbon fine particles are graphite and are a soft material, so that it is considered that the hardness of the DLC film is lowered. Therefore, when the DLC film is formed, carbon fine particles are prevented from flying to the base material 10 side by a method called filtering. Carbon ions have an electric charge, while carbon fine particles have no electric charge. Therefore, the flight path of carbon ions can be bent by adjusting the balance and strength of the electric field and the magnetic field, but the carbon fine particles go straight toward the base material 10. Therefore, by installing a shield between the carbon electrode and the base material 10 in the chamber and adjusting the balance and strength of the electric and magnetic fields, the carbon fine particles are prevented from reaching the base material 10 by the shield. At the same time, the carbon ions are made to fly around the shield so as to reach the base material 10. Since the DLC film formed while filtering in this way has high resistance, it is used as a protective film for improving the wear resistance of the contact portion of a member such as the contact member 100 that requires electrical conduction. It is not possible.

However, after diligent research, the inventors of the present invention applied the filtering method and adjusted the film forming conditions such as the balance and strength of the electric and magnetic fields or the film forming time, so that the carbon ions flying to the base material 10 side could be obtained. The ratio of the amount of carbon fine particles to the amount of carbon fine particles is controlled so that the conductive carbon fine particles 22 are contained in an area ratio of 1% or more and 80% or less when the conductive high hardness protective coating 20 is surface-observed as described above. It has been found that by forming a film, a conductive high hardness protective film 20 having a surface resistance value and a surface hardness within the above ranges and suitable for a contact portion of the contact member 100 can be obtained. Further, at that time, in addition to the method of arranging the shield between the cathode electrode and the film-forming surface of the base material 10, the angle formed by the electrode surface of the cathode electrode and the film-forming surface of the base material 10 can be adjusted. The carbon fine particles fly almost vertically from the electrode surface of the cathode electrode without placing a shield between them, while the ratio of the amount of carbon ions and carbon fine particles can be controlled by bending the flight path of carbon ions. I also found that there was. In either case, the electromagnetic field conditions at the time of arc discharge may be controlled to deflect the direction of carbon ion arrival. That is, the direction of arrival of carbon ions may be bent by the deflection action of the electromagnetic field. Further, by controlling the electromagnetic field conditions at the time of arc discharge, the size distribution of the conductive carbon fine particles 22 emitted from the carbon electrode can be appropriately adjusted. In the conductive high hardness protective film 20 formed in this way, the conductive carbon fine particles 22 can be uniformly dispersed in the carbon film 21. Further, in the conductive high hardness protective film 20 formed in this way, the conductive carbon fine particles 22 may protrude from the surface of the carbon film 21 as described above, but the surface can be easily polished after the film formation. The surface roughness (Ra) / film thickness ratio can be doubled or less.

(2) Film formation method of the metal intermediate layer 30 When the metal intermediate layer 30 between the base material 10 and the conductive high hardness protective film 20 is interposed, the metal intermediate layer 30 has a cathode arc similar to the conductive high hardness protective film 20. It is preferable to form a film by a vacuum vapor deposition method such as a method, a sputtering method, or an electron beam method. By first forming a metal intermediate layer 30 on the base material 10 by these methods, the conductive high hardness protective film 20 is subsequently formed on the surface of the metal intermediate layer 30 by using the same vacuum vapor deposition apparatus as described above. Can be formed into a film.

The metal intermediate layer 30 is a layer formed of the above-mentioned various metals or metal compounds. For example, when forming a metal compound film as the metal intermediate layer 30, for example, when forming a metal nitride film such as titanium nitride or chromium nitride, nitrogen is introduced into the chamber as a reaction gas. An appropriate reaction gas may be appropriately introduced according to the type of metal compound to be used.

When the metal intermediate layer 30 is formed, the metal fine particles 31 may be mixed in the layer at the time of forming the film, as in the case of forming the conductive high hardness protective film 20. The metal fine particles 31 may penetrate into the conductive high hardness protective film 20, or the metal fine particles 31 that have penetrated into the conductive high hardness protective film 20 may be exposed on the surface of the conductive high hardness protective film 20. As described above, such metal fine particles 31 contribute to improving the conductivity of the conductive high hardness protective coating 20 by mutual contact with the conductive carbon fine particles 22. Therefore, when the metal fine particles 31 are observed on the surface when the conductive high hardness protective film 20 is provided on the base material 10 via the metal intermediate layer 30, as described above, the conductive high hardness protective film 20 As the conductive fine particles observed on the surface of the above, the area of the metal fine particles 31 is taken into consideration in addition to the conductive carbon fine particles 22. Note that FIG. 2 shows an SEM photograph showing the surface of the metal intermediate layer 30 when the metal intermediate layer 30 is provided on the surface of the base material 10. However, the SEM photograph shown in FIG. 2 shows the state before the conductive high hardness protective film 20 is provided, and the portion seen as a white spot, a round shape, an elliptical shape, or the like is the metal fine particle 31.

The film thickness of the metal intermediate layer 30 may be 5 nm to 10 μm in order to increase the adhesion between the conductive high hardness protective film 20 and the base material 10 or to relieve the internal stress of the conductive high hardness protective film 20. It is more preferably 50 nm to 7 μm, and even more preferably 100 nm to 5 μm.

By the above method, the conductive high hardness protective film 20 according to the present invention can be provided on the base material 10 via the metal intermediate layer 30 which is an arbitrary layer, and the sliding contact member and the contact member according to the present invention can be provided. 100 can be manufactured. Next, the sliding contact member, the contact member 100, and the conductive high hardness protective coating 20 according to the present invention will be described more specifically with reference to Examples and Comparative Examples.

Three types of carbon-based coating films having different contents of the conductive carbon fine particles 22 were formed on a tungsten carbide (WC) substrate (20 mm × 20 mm × 0.7 mm). The specific procedure is as follows. First, the WC substrate was ultrasonically cleaned with acetone and ethanol for 5 minutes, respectively, and the surface was degreased and washed. This WC substrate was set at a predetermined position in the chamber of the vacuum vapor deposition apparatus manufactured by Showa Vacuum Co., Ltd. A carbon electrode was used as the cathode electrode, and a molybdenum electrode was used as the anode electrode. Then, a shield was set at a predetermined position in the chamber, and the inside of the chamber was evacuated with a turbomolecular vacuum pump until the inside of the chamber reached 4 × 10 ^-4 pa. Next, 60 sccm (Standard Cubic Centimeter per Minute) of argon gas was introduced into the chamber, a DC voltage of 500 V was applied, argon bombarding was performed for 20 minutes, and the surface of the substrate was dry-cleaned. After that, a current of 140 A was applied on the carbon cathode to continuously operate the arc discharge to radiate carbon ions and carbon fine particles toward the anode side, and a carbon-based film having a film thickness of about 600 nm was formed on the WC substrate. ..

At that time, by changing the bias voltage on the WC substrate, carbon ions, the magnetic force in the carbon fine particle flying space, and the deflection rate, the balance and strength of the electric and magnetic fields in the chamber can be adjusted to adjust the balance and strength in the carbon film 21. As shown in Table 2 below, the content ratios of the conductive carbon fine particles 22 are set to 99%, 87%, and 20%, respectively, so that the area ratios are 1%, 13%, and 80%. , The carbon-based coatings of Example 1, Example 2, and Example 3, respectively. More specifically, in this embodiment, the vapor deposition apparatus is partially modified so that the angle formed by the electrode surface of the cathode electrode and the film formation surface of the base material 10 can be adjusted. Then, the deflection factor was set as the angle formed by the electrode surface of the cathode electrode and the film-forming surface of the base material 10. Then, as shown in Table 1, the bias voltage (V) and the magnetic field (T) applied to the substrate 10 were adjusted together with the deflection rate (°) to set the filtering rate as described above. However, this filtering condition differs depending on the configuration of the device, the size of the chamber, and the like. In addition to adjusting the electric and magnetic fields in the chamber, the film formation time may be adjusted as appropriate. Further, in the comparative example, a shield may be arranged between the electrode surface of the cathode electrode and the film-forming surface of the substrate 10 so that the deflection rate becomes 0 °.

H, N, F, Al, Si, Cr, Ag, Ti, Cu, Ni, W, Ta, Mo, Zr, B, Fe, Pt, P, S, I, Mg, during arc discharge on the carbon electrode. Any one element selected from the group consisting of Zn and Ge was simultaneously discharged by sputtering in the case of gas or metal, and added to the high-hardness carbon film under the same conditions as in Example 1. As a result, almost the same filtering rate was obtained at a film thickness of 600 nm.

Comparative example

Comparative Example in the same manner as in Example except that the filtering rate was set to 99.5% so that the content ratio of the conductive carbon fine particles 22 in the conductive high hardness protective film 20 was 0.5% in area ratio. A carbon-based film was formed.

[evaluation]
Table 2 shows the content ratio, surface resistance value and surface hardness of the conductive carbon fine particles 22 in the conductive high hardness protective film 20 according to the present invention formed in each example and the carbon-based film formed in the comparative example. The surface resistance value was measured with a two-terminal digital multimeter (Digital Multimeter SANWA PC20 manufactured by Sanwa Electric Meter Co., Ltd.). The surface hardness was measured 10 times with a pushing load of 5 mN using a nano indenter (ENT-2100 manufactured by Elionix Inc.) because the film thickness was thin, and the average of the obtained values was taken as the film hardness. Further, FIGS. 3A to 3C show SEM photographs (photographing magnification 2,000 times) of the surface of the conductive high hardness protective coating 20 of Examples 1 to 3. Further, FIG. 4 shows an SEM photograph (photographing magnification 300 times) of the surface of the carbon-based coating of the comparative example. From FIGS. 3A to 3C, it is observed that as the content ratio of the conductive carbon fine particles 22 increases, the number of the conductive carbon fine particles 22 appearing on the surface also increases. In each photograph, the portion that is seen as a white spot, a circle, an ellipse, or the like is the conductive carbon fine particles 22. Further, from Table 1, the surface hardness tends to decrease as the content ratio of the conductive carbon fine particles 22 increases, but even when the content ratio of the conductive carbon fine particles 22 is 80% in terms of area ratio, the surface hardness is 10 Gpa. However, it was confirmed that sufficient hardness for improving wear resistance can be obtained. Further, from Table 2, the resistance value of Example 1 containing 1% of the conductive carbon fine particles 22 in the area ratio is 1 × 10 ³ Ω, and the resistance value of the conductive carbon fine particles 22 is 13% in the area ratio from Examples 2 and 3. When the above was included, the resistance value became 0Ω, and it was confirmed that a highly conductive carbon-based film could be obtained.

From the above, as shown in Table 2, the resistance values of the carbon-based coatings of Examples 1 to 3 are smaller than 1 × 10 ³ Ω and have a surface hardness of 10 GPa or more. Even if the carbon-based coating is provided as a protective coating on a portion that is in electrical and mechanical contact with the member, wear resistance can be improved while ensuring continuity with other members. Therefore, when the conductive high hardness protective film according to the present invention is used for the contact member, transfer can be suppressed. Further, since the transfer is suppressed by the carbon-based film containing the conductive carbon fine particles 22, it is possible to provide a contact member and a sliding contact member that can be used even in a high temperature environment, unlike the method using a resin such as PTFE particles. can.

According to the present invention, while improving wear resistance, transfer is suppressed when used for a contact member, a sliding contact member that can be used even in a high temperature environment, and a high conductive hardness provided for such a sliding contact member. It is possible to provide a protective film, a contact member, and a method for manufacturing these sliding contact members. These members can be suitably used for various sliding portions or contact portions.

10 Base material 20 Conductive high hardness protective coating 21 Carbon coating 22 Conductive carbon fine particles 30 Metal intermediate layer 31 Metal fine particles 100 Contact member

Claims (8)

A sliding contact member characterized in that a conductive high hardness protective film made of a carbon-based film having a surface resistance value of less than 1 × 10 ³ Ω and a surface hardness of 10 GPa or more is provided on the surface of a base material. In the carbon-based coating, conductive fine particles are dispersed in a carbon coating containing carbon having a sp2 structure and carbon having a sp3 structure, and when the surface of the carbon-based coating is observed, the conductive fine particles are 1 in area ratio. The sliding contact member according to claim 1, which includes% or more and 80% or less. The carbon-based coating has H, N, F, Al, Si, Cr, Ag, Ti, Cu, Ni, W, Ta, Mo, Zr, B, Fe, Pt, P, S, I, as additive elements. The sliding contact member according to claim 1 or 2, which contains one or more elements selected from the group consisting of Mg, Zn and Ge. The sliding contact member according to any one of claims 1 to 3, wherein the carbon-based coating has a friction coefficient of 0.5 or less. The sliding contact member according to any one of claims 1 to 4, wherein the carbon-based film has a film thickness of 20 nm or more and 10 μm or less. The slide according to any one of claims 1 to 5, wherein the conductive high hardness protective film is provided at least on the surface of a terminal portion that is electrically and / or mechanically in contact with another member of the base material. Contact member. It is provided on the surface of a contact member that is electrically and / or mechanically in contact with another member, and is characterized by having a carbon-based coating having a surface resistance value of less than 1 × 10 ³ Ω and a surface hardness of 10 GPa or more. Conductive high hardness protective coating. When carbon plasma is generated by arc discharge, the ratio of carbon ions to carbon fine particles is controlled by the deflection action of the electromagnetic field to form a carbon film in which conductive carbon fine particles are dispersed on the surface of the base material. A method for manufacturing a sliding contact member, characterized in that a conductive high hardness protective film made of a carbon-based film having a surface resistance value of less than 1 × 10 ³ Ω and a surface hardness of 10 GPa or more is provided on the surface of the material.

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