JP7457638B2 - Sliding contact member, conductive high hardness protective coating, and manufacturing method of sliding contact member - Google Patents

Description

The present invention relates to a sliding contact member that can be electrically connected to semiconductors, electronic parts, various electronic devices and mechanical parts constructed using these, a conductive high-hardness protective coating, and a method for manufacturing the sliding contact member.

A semiconductor manufacturing process includes a wafer processing process called a "pre-process" and an assembly process called a "post-process". The front-end process refers to the steps leading up to manufacturing a large number of semiconductor chips on the wafer surface, and the back-end process involves cutting out semiconductor chips from the wafer and mounting (packaging) semiconductor integrated circuits (LSI, VLSI, ULSI, etc.) as final products. Refers to the process of obtaining parts. In the pre-process, a wafer inspection is performed using a probe called a probe pin, and defective semiconductor chips are removed to prevent them from being sent to the post-process. Also, in the post-process, mounted component inspection (also referred to as "package inspection" etc.) using probe pins is performed to eliminate defective products before shipping the product.

For example, in wafer inspection, a probe card appropriate for the object to be inspected is used. Probe pins are attached to the probe card. The probe pins are pressed against the semiconductor chip using spring pressure, bringing them into contact with the electronic terminal material of the semiconductor chip, and electrical characteristic tests such as continuity tests or operation tests are performed. In mounted component inspection, predetermined electrical characteristic tests are also performed on semiconductor packages. Products are judged as good or bad by such electrical characteristic tests, and the defective products are rejected.

Several hundred to several thousand, or even tens of thousands of such semiconductor integrated circuits are produced per day on one line or factory. Since the electrical property test described above is basically a 100% inspection, probe pins are pressed against the electronic terminal material depending on the number of products produced. Therefore, wear resistance is required at the contact portion of the probe pin with the terminal material.

Further, an oxide film is usually 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 depending on the object to be inspected. When the probe pin is pressed during inspection, the oxide film on the surface of the electronic terminal material is broken and the fresh electronic terminal material inside comes into contact with the probe pin. This allows the electrical characteristics of the object to be tested to be accurately evaluated. However, if soft materials such as solder are used as the electronic terminal material, these soft materials may adhere to the tip of the probe pin. Hereinafter, this phenomenon will be referred to as "transfer". When the transfer occurs, the sharpness of the contact portion of the probe pin is impaired, making it difficult to break the oxide film on the surface of the electronic terminal material to be inspected next.

In order to prevent such problems, the operator who performs the electrical characteristic 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 will be pressed against the electronic terminal material with a contact pressure higher than specified, which may damage the semiconductor chip or semiconductor package to be tested, or prevent accurate measurement. First, judgment errors may occur, such as determining a good product as a defective product. As a result, yield may deteriorate and productivity may drop significantly.

One of the causes of the above-mentioned transfer is wear of the contact portion. When the surface roughness of the contact portion increases with wear, soft electronic terminal materials such as solder easily adhere to the contact portion. Further, the contact portion of the probe pin is plated with a noble metal such as gold, gold alloy, or rhodium to improve conductivity. Solder is an alloy whose main ingredients are tin and lead, but it has a strong chemical bond with precious metals and easily adheres to the contact area.

Therefore, when plating probe pins with precious metals, transfer can be achieved by eutectoiding resin particles such as graphite particles or polytetrafluoroethylene (PTFE) particles that are less likely to form chemical bonds with solder. Efforts have been made to make it less likely to occur (for example, see Patent Document 1 and Patent Document 2). However, when these methods are adopted, there is a problem that the contact resistance of the probe pin increases. Generally, resin particles often have low heat resistance. For example, a burn-in test is conducted at a high temperature such as 150°C. Therefore, if it contains resin particles with low heat resistance, it cannot be used for probe pins used during burn-in tests. Furthermore, 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 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 difficult to occur. In particular, DLC has high hardness and a low coefficient of friction, so it is often used as a protective coating for sliding contact parts. However, DLC has a high resistance and is therefore unsuitable as a protective coating for probe pins.

Patent No. 4044926 Patent No. 3551411

The present invention has been made in view of the above-mentioned problems, and provides a sliding contact member that improves wear resistance, suppresses transfer when used as a contact member, and can be used even in high-temperature environments. It is an object of the present invention to provide a conductive high-hardness protective coating provided on sliding contact members 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 is provided with a terminal portion, and uses the terminal portion that electrically or electrically and mechanically contacts another member as a base material, and the surface of the base material is is provided with a conductive high-hardness protective coating made of a carbon-based coating that is not doped with metal and has a surface resistance value smaller than 1×10 ³ Ω and a surface hardness of 10 GPa or more, and the carbon-based coating has an sp2 Conductive carbon fine particles are dispersed in a carbon film containing carbon having a carbon structure and carbon having an sp3 structure, and when the surface of the carbon-based film is observed, the area ratio of conductive carbon fine particles is 1% or more and 80% or less. It is characterized by containing.

In the sliding contact member according to the present invention, it is preferable that the carbon-based coating has a friction coefficient of 0.5 or less.

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

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 electrically and/or mechanically contacts other members, and has a surface resistance value of 1×10 ³ Ω, has a surface hardness of 10 GPa or more, and is made of a carbon-based film that is not doped with metal , and the carbon-based film contains conductive carbon within the carbon film containing sp2-structured carbon and sp3-structured carbon. Carbon fine particles are dispersed therein, and when the surface of the carbon-based coating is observed, the conductive carbon fine particles are contained in an area ratio of 1% or more and 80% or less .

In order to achieve the above object, the manufacturing method for a sliding contact member according to the present invention is characterized in that, when carbon plasma is generated by arc discharge, the ratio of carbon ions and carbon microparticles is controlled by the deflection action of an electromagnetic field, and a terminal portion that electrically or electrically and mechanically contacts another member is used as a substrate, and a carbon coating having conductive carbon microparticles dispersed on the surface of the substrate is formed, so that the surface of the substrate is provided with a conductive high-hardness protective coating consisting of a carbon-based coating having a surface resistance value of less than 1 x ¹⁰³ Ω and a surface hardness of 10 GPa or more, the carbon coating containing sp2 carbon and sp3 carbon, the conductive microparticles being dispersed in the carbon coating, and the surface of the carbon-based coating being observed to contain conductive microparticles in an area ratio of 1% to 80% .

According to the present invention, a sliding contact member that improves wear resistance, suppresses transfer when used as a contact member, and can be used even in a high temperature environment, and a conductive high hardness provided in such a sliding contact member. A method for manufacturing a protective coating and a sliding contact member thereof can be provided.

(a) A diagram schematically showing a cross section of a conductive high-hardness coating provided on the surface of a base material. It is a 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 hard coating of Example 1 (magnification 2,000x), (b) SEM photograph showing the surface of the conductive hard coating of Example 2 (magnification 2, (c) is an SEM photograph (photographing magnification: 2,000 times) showing the surface of the conductive high-hardness coating of Example 3. This is a SEM photograph (photographing magnification: 300 times) showing the surface of the conductive high-hardness coating of Comparative Example 1.

Hereinafter, a sliding contact member, a conductive high-hardness protective coating, and a method for manufacturing the same according to the present invention will be explained.

1. Sliding Member The sliding member according to the present invention is a member that comes into contact with another member and has a probability of sliding against the other member when it comes into contact with the other member. The sliding contact member may be a member that is required to have conductivity with other members, or may be a member that is not required to have conductivity. For example, it may be a member that requires electrical conduction with other members, such as the contact member described below, or it may be used in milling machines such as various drills, end mills, and milling cutters that are attached to electric drills. It may be a member that comes into direct contact with various cutting tools used in the manufacturing process, or other members such as a mold or a wafer cassette, and which does not require electrical conductivity. Alternatively, it may be a sliding member that comes into contact with another member and slides together while moving relative to the other member. However, since the conductive high-hardness protective coating according to the present invention has a low surface resistance, it is preferable that the sliding contact member is not a member that requires insulation. By having the conductive high-hardness protective coating according to the present invention, the sliding contact member according to the present invention has improved wear resistance and maintains a low resistance value when compared to a component without the conductive high-hardness protective coating. can do. Therefore, if applied to a contact member that has a terminal part that electrically and/or mechanically contacts other members, it is possible to maintain good electrical conductivity between the contact member and other members, and to connect the other members mechanically. wear caused by physical contact can be suppressed. Examples of contact members include probe pins used in contact with electrodes of an object to be inspected during wafer inspection, package inspection, etc. performed in a semiconductor manufacturing process. The sliding contact member and the contact member according to the present invention will be explained below by taking the contact member as an example. However, the sliding contact member according to the present invention includes contact members such as probe pins, terminals of mechanical relays, and rotation of motors. The present invention can be applied to various terminal members having terminal portions that electrically and mechanically contact other members such as children, as well as the various tools described above.

The structure of the contact member is schematically shown in FIG. In the example shown in FIG. 1, the contact member 100 includes a conductive high-hardness protective coating 20 on the surface of a base material 10, and a metal intermediate layer 30 is provided between the base material 10 and the conductive high-hardness protective coating 20. It is being This metal intermediate layer 30 has an arbitrary layer configuration in the present invention. Further, in the example shown in FIG. 1, the conductive high-hardness protective coating 20 includes conductive carbon fine particles 22 within the carbon coating 21 serving as a base layer. Furthermore, the metal fine particles 31 deposited in the metal intermediate layer 30 are present at the interface with the conductive high-hardness protective coating 20 . Hereinafter, the base material 10, the conductive high-hardness protective coating 20, and the metal intermediate layer 30 will be explained in this order.

(1) Base material 10
The base material 10 of the contact member 100 may be made of various metals such as copper, iron, nickel, and aluminum, or various alloys such as copper alloy, iron alloy, nickel alloy, and aluminum alloy. 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 either. For example, if the contact member 100 is a probe pin, it is sufficient to satisfy the shape required for the terminal portion of the probe pin, and the contact member 100 may have any shape depending on the purpose of the contact member 100. In addition, when the sliding contact member is not required to have electrical conductivity with other members, 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 also be a resin base material or the like.

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

The conductive high-hardness protective coating 20 is made of a carbon-based material having a surface resistance value of less 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. Consists of a coating. Here, graphite and diamond-like carbon (DLC) are known as carbon-based materials. Since graphite is electrically conductive, when a thin film made of graphite is provided at a portion that comes into 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, its surface hardness is lower than 10 GPa, and only a small effect of improving the wear resistance of the contact portion can be obtained. 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 area is high. However, the surface resistance value of DLC is 1×10 ³ Ω or more, and the resistance of the contact portion increases. Therefore, DLC is not suitable as a protective coating for contact members. After intensive research by the present inventors, for example, it was discovered that 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 can be obtained by the method described below. By providing the conductive high-hardness protective coating 20 on the surface of the base material 10, it is possible to provide a contact member (and sliding contact member) that improves wear resistance, suppresses transfer, and can be used even in high-temperature environments. I found that. Hereinafter, preferred embodiments of the conductive high-hardness protective coating 20 will be described.

For example, as shown in FIG. 1, the conductive high-hardness protective film 20 is preferably a carbon-based film in which conductive fine particles such as conductive carbon fine particles 22 are dispersed in a carbon film 21 serving as a base layer. By using such a carbon-based coating, the surface resistance value can be made smaller than 1×10 ³ Ω and the surface hardness can be made more than 10 GPa, and it has electrical properties and mechanical properties suitable for a protective coating for contact members. can be realized.

The carbon coating 21 preferably contains carbon of sp2 structure and carbon of sp3 structure. For example, it is preferably a so-called DLC such as an amorphous carbon coating having a relatively high carbon content with an sp2 structure containing carbon of sp2 structure and carbon of sp3 structure, or a tetrahedral carbon coating having a relatively high carbon content with sp3 structure, and is particularly preferably a tetrahedral carbon coating. The carbon coating may or may not contain hydrogen. When the carbon content of the sp3 structure is expressed as "sp2/(sp3+sp3)×100, where sp2 and sp3 are the numbers of carbon atoms in the sp2 structure and the sp3 structure when elemental analysis of the carbon coating 21 is performed by X-ray photoelectron spectroscopy (XPS)," if the carbon content of the sp3 structure is 20% or more and 90% or less, the surface resistivity can be made 1×10 ³ Ω or more and 1×10 ¹² Ω or less, and a surface hardness of 10 GPa or more can be obtained.

Further, the carbon film 21 includes H, N, F, Al, Si, Cr, Ag, Ti, Cu, Ni, W, Ta, Mo, Zr, B, Fe, Pt, P, S, I as additive elements. , Mg, Zn, and Ge. These elements can be included in the DLC film when the DLC film is formed by a vacuum evaporation method.

Examples of the conductive fine particles include conductive carbon fine particles 22 such as graphite. Graphite is highly conductive. Therefore, by dispersing a predetermined amount of conductive carbon fine particles 22 in the carbon film 21, it is possible to obtain a conductive high-hardness protective film 20 with a surface resistance value of less than 1×10 ³ Ω. In addition to the conductive carbon particles 22 as conductive fine particles, when the conductive high-hardness protective coating 20 is provided on the base material 10 via the metal intermediate layer 30 as described later, the metal intermediate layer 30 is formed. Examples include metal fine particles 31 generated during film formation. 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-sectional area") is 0.01 μm ² to 1 mm ² when the surface of the conductive high-hardness protective coating 20 is observed. preferable. It is preferable to uniformly disperse conductive fine particles having such a size within the carbon film 21 in order to obtain desired electrical characteristics.

In addition, the content of the conductive fine particles in the conductive hardness protective coating 20 is preferably 1% or more and 80% or less in terms of area ratio when the conductive hardness protective coating 20 is observed on the surface by a scanning electron microscope. More specifically, a SEM photograph of the surface of the conductive hardness protective coating 20 taken with a scanning electron microscope (e.g., JSM-6510A manufactured by JEOL Ltd., secondary electron image) at a magnification of 2,000 times is subjected to fine particle analysis using WinROOF image processing software (WinROOF2018 Standard version manufactured by Mitani Shoji Co., Ltd.), and the ratio ((conductive carbon fine particle area/conductive hardness protective coating area) x 100) of the area occupied by the conductive fine particles observed on the surface (however, the sum of the areas equivalent to the cross-sectional areas of the conductive fine particles in the horizontal plane (i.e., the sum of the projected areas of the particles)) to the surface area of the conductive hardness protective coating in the observation region can be determined as the content of the conductive fine particles in the conductive hardness protective coating 20.

When 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 coating 21 is 1×10 ³ Ω or more and 1×10 ¹² Ω or less, if the content of conductive fine particles such as the conductive carbon fine particles 22 becomes too small, the conductive high-hardness protective coating It becomes difficult to reduce the surface resistance value of 20 to less than 1×10 ³ Ω. On the other hand, the hardness of the conductive carbon particles 22 is low. Therefore, if the content of the conductive carbon fine particles 22 in the carbon coating 21 becomes too large, the surface hardness of the conductive high-hardness protective coating 20 becomes less than 10 GPa, resulting in the effect of improving the wear resistance of the contact member. things become difficult. From this point of view, the content ratio of the conductive fine particles in the conductive high-hardness protective coating 20 is preferably 1% or more and 80% or less in terms of area ratio, more preferably 3% or more and 70% or less. It is preferably 5% or more and 60% or less. Note that when the content ratio of conductive fine particles in the conductive high-hardness protective coating 20 is 1% or more and 80% or less in terms of area ratio, the surface hardness is 10 GPa or more, and for example, when the content ratio is 13%. A surface hardness of 50 GPa or more has been achieved. If the surface hardness of the conductive high-hardness protective coating 20 is 10 GPa or more, it is sufficient to improve the wear resistance of the contact member. If it is 10 GPa or more, an effect of improving wear resistance can be obtained, and for example, if it is 50 GPa or more, a sufficient effect of improving wear resistance can be obtained.

Further, the 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 will be difficult to incorporate the conductive carbon fine particles 22 into 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 coating 20 increases, and it becomes difficult to reduce it to less 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 will deteriorate. From these viewpoints, the thickness of the conductive high-hardness protective film 20 is more preferably 50 nm or more and 5 μm or less, and even more 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, more preferably 0.3 or less. As described above, when graphite is dispersed in the carbon coating 21 as the conductive carbon particles 22, the friction coefficient of graphite is low, so the probability that the friction coefficient will be larger than 0.4 is low.

In addition, it is preferable that the surface roughness (Ra)/film thickness ratio of the conductive high-hardness protective coating 20 is 2 times or less. When the conductive carbon fine particles 22 are dispersed in the carbon coating 21, the conductive carbon fine particles 22 may protrude from the surface of the carbon coating 21 during the formation of the conductive high-hardness protective coating 20, resulting in a rough surface roughness. If the surface roughness (Ra)/film thickness ratio exceeds 2 times, the above-mentioned transfer may occur easily when the contact portion of the contact member 100 is electrically and mechanically brought into contact with another member, which is not preferable. The conductive carbon fine particles 22 are made of soft particles such as graphite. Therefore, it is easy to bring the surface roughness within the above range by polishing the surface of the conductive high-hardness protective coating 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 that has good chemical adhesion to both the base material 10 and the conductive high-hardness protective coating 20, and can be provided as necessary. Examples of metals that have good chemical adhesion to both the base material 10 and the conductive high-hardness protective coating 20 include Fe, Cr, and Ti. By providing a layer made of these metals and/or a metal compound thereof such as N, O, C, etc. as the metal intermediate layer 30 between the base material 10 and the conductive high hardness protective coating 20, the base material 10 can be formed. It becomes possible to bond each of the above-mentioned materials and carbon, which is a constituent material of the conductive high-hardness protective coating 20, well. However, if 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 directly provided 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 evaporation method as described later. During the formation of the metal intermediate layer by the vacuum evaporation method, metal fine particles 31 are generated in addition to 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 coating 20 is provided on the surface of the base material 10 via the metal intermediate layer 30, the metal fine particles 31 are formed in the carbon coating 21 as shown in FIG. Since some of the carbon particles are taken in, the surface resistance value of the conductive high-hardness protective coating 20 is reduced due to mutual contact between the conductive carbon particles 22 in the carbon coating 21 and the metal particles 31, and the conductivity is further improved.

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, the contact member 100 schematically shown in FIG. 1 will be described as an example of the sliding contact member. The contact member 100 creates a carbon film 21 in which conductive carbon particles 22 are dispersed on the surface of the base material 10 by controlling the ratio of carbon ions and carbon particles by deflection by an electromagnetic field when carbon plasma is generated by arc discharge. A conductive high-hardness protective coating 20 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 is provided on the surface of the base material by forming a film. Here, after forming the metal intermediate layer 30 on the surface of the base material 10, the conductive high-hardness protective coating 20 may be formed.

(1) Method of forming 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 evaporation method. As the vacuum evaporation method, for example, a cathode arc method, a sputtering method, an electron beam method, etc. can be adopted. In particular, when forming the conductive high-hardness protective film 20 according to the present invention, it is preferable to employ a 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 particles, and the carbon ions are converted into a base by emitting it toward 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 conductive carbon particles 22 can be formed on the base material 10.

In the cathode arc method described above, arc discharge is generally generated by flowing a high current under a low voltage. If the carbon electrode is used as a cathode electrode as described above, carbon ions can be released from the carbon electrode along with arc discharge. Furthermore, carbon fine particles are also released from the carbon electrode due to the heat generated by arc discharge. For example, the DLC film is also formed by the cathode arc method. When carbon particles are mixed into the DLC film, the hardness of the DLC film may be reduced because the carbon particles are graphite, which is a soft material. Therefore, when forming a DLC film, a method called filtering is used to prevent carbon particles from flying toward the base material 10 side. Carbon ions have an electric charge, while carbon particles do not have an electric charge. Therefore, by adjusting the balance and strength of the electric field and magnetic field, it is possible to bend the flying path of the carbon ions, but the carbon fine particles continue 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 field and magnetic field, the carbon particles can be prevented from reaching the base material 10 by the shield. At the same time, carbon ions are made to fly around the shield and reach the base material 10. Since the DLC film formed while performing filtering in this manner has a high resistance, it is used as a protective coating to improve the wear resistance of the contact portion of a member such as the contact member 100 that requires electrical continuity. It is not possible.

However, after extensive research, the inventors of the present invention applied a filtering method and adjusted the film forming conditions such as the balance and strength of the electric field and magnetic field or the film forming time, thereby reducing the amount of carbon ions flying toward the base material 10. and the amount of carbon fine particles so that the conductive carbon fine particles 22 are contained in an area ratio of 1% to 80% when the surface of the conductive high-hardness protective coating 20 is observed as described above. It has been found that by forming a film, a conductive high-hardness protective coating 20 having a surface resistance value and surface hardness within the above range and suitable for the contact portion of the contact member 100 can be obtained. In addition to placing a shield between the cathode electrode and the film-forming surface of the base material 10, it is also possible to adjust the angle between the electrode surface of the cathode electrode and the film-forming surface of the base material 10. , the carbon particles can be flown almost perpendicularly from the electrode surface of the cathode without placing a shield between them, while the ratio of the amounts of carbon ions and carbon particles can be controlled by bending the flying path of the carbon ions. I also discovered something. In either case, the electromagnetic field conditions during arc discharge may be controlled to deflect the flying direction of carbon ions. That is, the direction in which carbon ions fly can be bent by the deflection effect of an electromagnetic field. Further, by controlling the electromagnetic field conditions during arc discharge, the size distribution and the like of the conductive carbon particles 22 emitted from the carbon electrode can be adjusted as appropriate. The conductive carbon fine particles 22 can be uniformly dispersed in the carbon film 21 in the conductive high-hardness protective film 20 formed in this manner. In addition, in the conductive high-hardness protective coating 20 formed in this manner, the conductive carbon fine particles 22 may protrude from the surface of the carbon coating 21 as described above, but this can be easily prevented by polishing the surface after the film is formed. The surface roughness (Ra)/film thickness ratio can be made twice or less.

(2) Method of forming metal intermediate layer 30 When the metal intermediate layer 30 is interposed between the substrate 10 and the conductive high-hardness protective coating 20, the metal intermediate layer 30 is preferably formed by a vacuum deposition method such as a cathodic arc method, a sputtering method, or an electron beam method, in the same manner as the conductive high-hardness protective coating 20. By first forming the metal intermediate layer 30 on the substrate 10 by these methods, it is possible to subsequently form the conductive high-hardness protective coating 20 on the surface of the metal intermediate layer 30 as described above using the same vacuum deposition apparatus.

The metal intermediate layer 30 is a layer formed from the various metals or metal compounds mentioned above. 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 may be introduced into the chamber as a reactive gas. An appropriate reaction gas may be introduced depending on the type of metal compound to be used.

When forming the metal intermediate layer 30, metal fine particles 31 may be mixed into the layer during film formation, as in the case of forming the conductive high-hardness protective coating 20. The metal fine particles 31 may penetrate into the conductive high-hardness protective coating 20, or the metal fine particles 31 that have penetrated into the conductive high-hardness protective coating 20 may be exposed on the surface of the conductive high-hardness protective coating 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 conductive high-hardness protective coating 20 is provided on the substrate 10 via the metal intermediate layer 30, if the metal fine particles 31 are observed on the surface, as described above, the area of the metal fine particles 31 in addition to the conductive carbon fine particles 22 is taken into consideration as the conductive fine particles observed on the surface of the conductive high-hardness protective coating 20. Note that FIG. 2 shows an SEM photograph of the surface of the metal intermediate layer 30 when the metal intermediate layer 30 is provided on the surface of the substrate 10. However, the SEM photograph shown in Figure 2 shows the state before the conductive high-hardness protective coating 20 is applied, and the white dots or round or elliptical parts are metal particles 31.

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

By the above method, the conductive high hardness protective coating 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 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 in more detail with reference to Examples and Comparative Examples.

Three types of carbon-based films having different content ratios of conductive carbon particles 22 were formed on a tungsten carbide (WC) base material (20 mm x 20 mm x 0.7 mm). The specific steps are as follows. First, the WC base material was subjected to ultrasonic cleaning for 5 minutes each using acetone and ethanol to degrease and clean the surface. This WC base material was set at a predetermined position in the chamber of a vacuum evaporation device manufactured by Showa Shinku Co., Ltd. Further, 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 inside the chamber, and the inside of the chamber was evacuated to a pressure of 4×10 ⁻⁴ pa using a turbo molecular vacuum pump. Next, 60 sccm (Standard Cubic Centimeters per Minute) of argon gas was introduced into the chamber, a DC voltage of 500 V was applied, and argon bombardment was performed for 20 minutes to dry clean the surface of the substrate. Thereafter, a current of 140 A was applied to the carbon cathode, and arc discharge was continuously operated to emit carbon ions and carbon particles toward the anode to form a carbon-based film with a thickness of about 600 nm on the WC substrate. .

At that time, by changing the bias voltage on the WC substrate, the magnetic force in the space in which carbon ions and carbon particles fly, and the deflection rate, the balance and strength of the electric field and magnetic field in the chamber are adjusted. As shown in Table 2 below, the content ratio of the conductive carbon particles 22 is 1%, 13%, and 80% in area ratio, and the filtering rate is 99%, 87%, and 20%, respectively. , and carbon-based coatings of Example 1, Example 2, and Example 3, respectively. More specifically, in this example, the vapor deposition apparatus was partially modified so that the angle between the electrode surface of the cathode electrode and the film-forming surface of the base material 10 could be adjusted. The deflection rate was defined as the angle between 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 magnetic field (T) applied to the substrate 10 as well as the deflection rate (°) were adjusted to obtain the filtering rate as described above. However, this filtering condition varies depending on the configuration of the device, the size of the chamber, etc. Further, in addition to adjusting the electric field, magnetic field, etc. in the chamber, the film forming time may be adjusted as appropriate. Further, in the comparative example, a shield may be placed between the electrode surface of the cathode electrode and the film-forming surface of the substrate 10 so that the deflection rate is 0°.

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

Comparative example

A comparative example was carried out in the same manner as in the 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 coating 20 was 0.5% in terms of 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 coating 20 according to the present invention formed in each example and the carbon-based coating formed in the comparative example. The surface resistance value was measured using a two-terminal digital multimeter (Digital Multimeter SANWA PC20 manufactured by Sanwa Electric Instruments Co., Ltd.). The surface hardness was measured 10 times with a pressing load of 5 mN using a nanoindenter (ENT-2100 manufactured by Elionix Co., Ltd.) because the film thickness was thin, and the average of the obtained values was taken as the hardness of the film. In addition, Figures 3(a) to (c) show SEM photographs (magnification 2,000 times) of the surface of the conductive high-hardness protective coating 20 of Examples 1 to 3. In addition, Figure 4 shows an SEM photograph (magnification 300 times) of the surface of the carbon-based coating of the comparative example. 3(a) to (c), it is observed that the number of conductive carbon particles 22 appearing on the surface increases as the content ratio of the conductive carbon particles 22 increases. In each photograph, the white dots or the parts that are seen as round or elliptical are the conductive carbon particles 22. In addition, from Table 1, it is seen that the surface hardness tends to decrease as the content ratio of the conductive carbon particles 22 increases, but even when the content ratio of the conductive carbon particles 22 is 80% by area ratio, it is confirmed that the surface hardness is 10 GPa, and a sufficient hardness for improving abrasion resistance can be obtained. In addition, from Table 2, it is confirmed that Example 1 containing 1% of the conductive carbon particles 22 by area ratio has a resistance value of 1×10 ³ Ω, and from Examples 2 and 3, when the conductive carbon particles 22 are contained by 13% or more by area ratio, the resistance value is 0 Ω, and it is confirmed that a carbon-based coating with high conductivity can 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 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 material, it is possible to improve wear resistance while ensuring conduction with other members. Therefore, when the conductive high-hardness protective coating according to the present invention is used in a contact member, transfer can be suppressed. Furthermore, since transfer is suppressed by a carbon-based coating containing conductive carbon fine particles 22, it is possible to provide contact members and sliding contact members that can be used even in high-temperature environments, unlike methods using resins such as PTFE particles. can.

The present invention provides a sliding contact member that has improved wear resistance, suppresses transfer when used as a contact member, and can be used in high-temperature environments, a conductive high-hardness protective coating that is provided on such a sliding contact member, or a contact member, and a method for manufacturing such a sliding contact member. These members can be suitably used for various sliding parts or contact parts.

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 (5)

The terminal portion is a substrate that electrically or electrically and mechanically contacts another member, and the substrate is provided on a surface thereof with a conductive, high-hardness protective coating having a surface resistance of less than 1×10 ³ Ω and a surface hardness of 10 GPa or more , the conductive, high-hardness protective coating being made of a carbon-based coating that is not doped with a metal ;
The carbon-based coating has conductive carbon particles dispersed therein, the conductive carbon particles being included in an area ratio of 1% to 80% when the surface of the carbon-based coating is observed. The sliding contact member according to claim 1, wherein the carbon-based coating has a friction coefficient of 0.5 or less. The sliding contact member according to claim 1 or 2, wherein the carbon-based coating has a thickness of 20 nm or more and 10 μm or less. A terminal that is provided on the surface of a terminal that is electrically or electrically and mechanically in contact with other members, has a surface resistance value of less than 1×10 ³ Ω, a surface hardness of 10 GPa or more , and is not doped with metal. Consisting of a carbon-based coating without
The carbon-based film has conductive carbon fine particles dispersed within the carbon film containing sp2-structure carbon and sp3-structure carbon, and when the surface of the carbon-based film is observed, the area ratio of the conductive carbon fine particles is A conductive high hardness protective coating characterized by containing 1% or more and 80% or less of. When carbon plasma is generated by arc discharge, the ratio of carbon ions and carbon particles is controlled by the deflection effect of the electromagnetic field, so that the terminal part that comes into contact with other parts electrically or electrically and mechanically can be made into a base material. A carbon film having conductive carbon fine particles dispersed therein is formed on the surface of the base material, and 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 formed on the surface of the base material. Conductive carbon particles are dispersed within the carbon film containing sp2-structure carbon and sp3-structure carbon, and when the surface of the carbon-based film is observed, the area ratio of the conductive carbon particles is A method for manufacturing a sliding contact member, comprising providing a conductive high-hardness protective coating made of a carbon-based coating containing 1% or more and 80% or less.

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