JP6840633B2 - Metallic fiber sheets, wiring members, and busbars - Google Patents

Description

The present invention relates to metal fiber sheets, wiring members, and bus bars.

As a conductive path in an electric circuit, a conductive wiring member is used in a wide range of industrial fields such as semiconductors, automobiles, and nuclear power. Since the wiring member is required to have high conductivity, metal pieces such as aluminum and copper are used as the material of the wiring member.
For example, a plasma processing apparatus that performs processing such as etching and thin film formation in the semiconductor field includes a wiring member for energizing an electrode with a high current. The plasma processing apparatus generates plasma from the process gas by energizing the electrodes from the power source with a high current value via the wiring member. Such a wiring member is made of aluminum, a metal piece such as copper, or the like.

Wiring members of metal pieces such as aluminum and copper have high conductivity, but when energized with a high current value, the wiring members of metal pieces generate heat. When such heat is transferred to a device portion around the wiring member that is easily affected by heat such as a power supply, various problems occur. Therefore, an attempt has been made to dissipate the heat generated by the wiring member (Patent Document 1). ~ 3).

Patent Document 1 discloses a wiring member used in the nuclear power field. In the wiring member described in Patent Document 1, a plurality of conductors having a hollow portion serving as a flow path for the refrigerant are arranged so that the heat-generating wiring member can be cooled.
Patent Document 2 discloses a wiring member used for a feeding rod of a plasma processing apparatus. The power feeding rod described in Patent Document 2 includes a conductive wiring member and a hollow portion for flowing a refrigerant such as air. The power feeding rod of Patent Document 1 is provided with a protrusion in the hollow portion to enhance the cooling effect by the refrigerant and prevent the wiring member from overheating.
Patent Document 3 discloses a bus bar which is a wiring member used in the automobile field. The wiring member described in Patent Document 3 has a vent hole attached with an inclination angle. Since the bus bar has ventilation holes, air can enter the hollow portion and dissipate heat from the inner surface of the hollow portion of the bus bar.

Japanese Unexamined Patent Publication No. 2000-12197 Japanese Unexamined Patent Publication No. 2003-282544 Japanese Unexamined Patent Publication No. 2004-80972

However, since the wiring members described in Patent Documents 1 to 3 use a solid material having high heat transfer properties, it is difficult to suppress the heat transferred through the wiring members. Therefore, the wiring member adjacent to the high-temperature electrode or the like transfers the high heat of the electrode or the like to the device portion such as the power supply.
For example, in a plasma processing apparatus or the like in the semiconductor industry, it is desired to energize an electrode with a higher current value from the viewpoint of productivity such as thin film formation. However, when the electrode is energized with a higher current value, the electrode further generates heat. However, since the conventional wiring member uses a solid material having high heat transfer property as a material, it is not possible to suppress the heat transferred to other device parts such as a power supply. Therefore, in the plasma processing apparatus in which the electrode and the power supply are connected by the conventional wiring member, it is not possible to energize at a desirable current value, and it is not possible to improve the productivity.

Further, for example, in an electric vehicle in the automobile industry, a bus bar is provided between the fuse and the battery unit. Since the temperature of the fuse rises significantly during rapid charging of an electric vehicle and during high-power running, a temperature gradient is likely to occur between the fuse and the battery unit having a temperature rise lower than that of the fuse. Due to this temperature gradient, heat is transferred from the fuse to the battery, which causes the battery to deteriorate quickly.
When a bus bar is provided between the fuse and the battery unit in this way, a heat generation amount exceeding the heat generation amount of the bus bar itself is added to the bus bar from the fuse, so that the bus bar used for an electric vehicle or the like is higher. Cooling efficiency is required. Further, it is conceivable that the battery deteriorates quickly, resulting in a decrease in the running performance of the electric vehicle when it is used in the electric vehicle. The above-mentioned problems related to heat transmitted through conductive paths such as bus bars are not limited to electric circuits used in the semiconductor industry and the automobile industry, and in particular, electric circuits through which high voltage and large current flow and high frequency power supplies are used. This is a common problem in various industrial fields.

The present invention has been made in view of the above background, and an object of the present invention is to provide a metal fiber sheet, a wiring member, and a bus bar which have the same conductivity as a conventional wiring member but have low heat conductivity.

The present invention has the following aspects.
[1] A metal fiber sheet containing at least one of a copper fiber and an aluminum fiber, wherein the fibers contained in the metal fiber sheet are bonded to each other at least in part, and is the same as the metal fiber sheet. A metal fiber sheet having a transmission attenuation rate difference of ± 5% or less and a thermal conductivity of 150 W / m · K or less from a solid material having a composition.
[2] The metal fiber sheet according to [1], wherein the fibers are bonded to each other by sintering.
[3] A wiring member using the metal fiber sheet according to [1] or [2].
[4] A bus bar using the metal fiber sheet according to [1] or [2].

According to the present invention, it is possible to provide a metal fiber sheet, a wiring member, and a bus bar having low heat conductivity while having the same conductivity as a conventional wiring member.

It is sectional drawing which shows an example of the structure for demonstrating the wiring member which concerns on one Embodiment to which this invention is applied. It is a schematic diagram of the electric circuit of the drive system of an electric vehicle. It is a mapping figure of the metal fiber sheet cut piece for measuring the coefficient of variation of the basis weight. It is a graph which shows the relationship between the applied frequency and the transmission attenuation rate. It is a graph which shows the relationship between the porosity and the thermal conductivity.

The definitions of the following terms apply throughout the specification and claims.
The "solid material" means, in principle, a material such as a metal piece made of copper, a metal plate, and a metal foil.
"Transmission attenuation (unit:%)" is the amount of transmission loss of a microstrip substrate with a fiber sheet connected to the ground side, and is a reflection measured by a network analyzer ("PNA-L N5230C" manufactured by Agilent Technologies). It is a value calculated by the following formula from the coefficient | S ₁₁ | and the transmission coefficient | S _{21 |.}
(Transmission attenuation rate (%)) = 1- (| S ₁₁ | ² + | S ₂₁ | ² ) x 100
"Thermal conductivity (unit: (W / m · K)" is the thermal diffusivity measured by the optical exchange method ("LaserPIT" manufactured by Advance Riko Co., Ltd.) and the specific heat measured by DSC (differential scanning calorimetry). , A value calculated by multiplying the bulk density of the fiber sheet.
The "copper fibers" means a fiber composed of copper, the "copper fibers" may include other components such as unavoidable impurities as long as this does not compromise the objects of the invention.
“Homogeneity” means that there is little variation in the sheet having characteristics such as electrical characteristics, physical characteristics, and air permeability characteristics of the sheet composed of fibers. As an index of homogeneity, for example, the coefficient of variation (CV value) of the basis weight specified in JIS Z8101 per ^{1 cm 2 can be adopted.}
The "average fiber diameter" refers to the cross-sectional area perpendicular to the longitudinal direction of the copper fiber calculated by a known calculation method based on the vertical cross sections of the metal fiber sheet imaged with a microscope at any plurality of points, and the cut. It is an additive average value of the area diameter derived by calculating the diameter of a perfect circle having the same area as the area. The plurality of locations may be, for example, 20 locations.
The "average fiber length" is an arithmetic mean value obtained by measuring the length of a plurality of fibers randomly selected by a microscope in the longitudinal direction of the fibers. If the fiber is not straight, it shall be the length of the curve along the fiber. The plurality of lines may be, for example, 20 lines.
The "sheet thickness" is, for example, when an arbitrary number of measurement points of a metal fiber sheet are measured with a film thickness meter of a terminal drop type by air (for example, "Digimatic Indicator ID-C112X" manufactured by Mitutoyo Co., Ltd.). It is the arithmetic mean value of.
The "space factor" is the ratio of the portion where the fiber exists to the volume of the fiber sheet, and is calculated by the following formula from the basis weight, thickness, and true density of the fiber of the fiber sheet. When the fiber sheet contains multiple types of fibers, the space factor can be calculated by adopting the true density value that reflects the composition ratio of each fiber.
(Space factor (%)) = (Fiber sheet basis weight) / ((Fiber sheet thickness) x (True density)) x 100
The "porosity" is the ratio of the portion where the void exists to the volume of the fiber sheet, and is calculated by the following formula from the basis weight, the thickness, and the true density of the fiber of the fiber sheet. When the fiber sheet contains a plurality of types of fibers, the space factor can be calculated by adopting a true density value that reflects the composition ratio of each fiber.
(Porosity (%)) = (1- (Fiber sheet basis weight) / ((Fiber sheet thickness) x (True density))) x 100

[Metal fiber sheet]
Hereinafter, the metal fiber sheet of one embodiment to which the present invention is applied will be described in detail, but the metal fiber sheet of the present invention is not limited to the following description. In the drawings used in the following description, the dimensional ratios and the like of each component are not always the same as the actual ones.

The metal fiber sheet of the present embodiment includes at least one of a copper fiber and an aluminum fiber. The metal fiber sheet of the present embodiment may contain only copper fibers, may contain only aluminum fibers, or may contain copper fibers and aluminum fibers. Further, the metal fiber sheet of the present embodiment may further contain copper fibers, metal fibers other than aluminum fibers, and fibers other than metal fibers as long as the conductivity is not impaired. Hereinafter, the metal fiber sheet mainly composed of copper fibers may be referred to as a copper fiber sheet, and the metal fiber sheet mainly composed of aluminum fibers may be referred to as an aluminum fiber sheet.
The metal fiber sheet of the present embodiment can have an arbitrary sheet structure. For example, the metal fiber sheet of the present embodiment may be a non-woven fabric in which fibers are randomly entangled, or may be a woven fabric having regularity.

In the metal fiber sheet of the present embodiment, the fibers contained in the metal fiber sheet of the present embodiment are bonded to each other at least in part. The fact that the fibers contained in the metal fiber sheet of the present embodiment are bonded to each other means that, for example, when the metal fibers of the present embodiment contain copper fibers and aluminum fibers, the copper fibers and aluminum are bound to each other. It means that the fibers or the copper fibers and the aluminum fibers are physically fixed to each other to form a binding portion.
In the metal fiber sheet of the present embodiment, the fibers contained in the metal fiber sheet of the present embodiment may be directly fixed at the binding portion. Further, in the metal fiber sheet of the present embodiment, the fibers contained in the metal fiber sheet of the present embodiment are indirectly fixed to each other via a copper component, an aluminum component, or a metal component other than copper and aluminum. May be.

Examples of metals other than copper and aluminum include stainless steel, iron, nickel, chromium, and the like, but are not particularly limited. The metal other than copper and aluminum may be a noble metal such as gold, platinum, silver, palladium, rhodium, iridium, ruthenium, and osmium.
Ingredients other than metal include polyethylene terephthalate (PET) resin, polyvinyl alcohol (PVA), polyethylene, and polyolefins such as polypropylene, polyvinyl chloride resin, aramid resin, nylon, acrylic resin, and fibrous materials thereof. Examples thereof include organic substances having a binding property and a supporting property. These organic substances can be used, for example, to assist / improve the morphological maintainability at the time of producing a metal fiber sheet.

Since the fibers contained in the metal fiber sheet of the present embodiment are bonded to each other at least in part, the metal fiber sheet of the present embodiment can be provided with conductivity.
The difference in transmission attenuation between the metal fiber sheet of the present embodiment and the solid material having the same composition is within ± 5% in each frequency band from the applied frequency of 10 MHz to 10 GHz, preferably ± at the applied frequency of 1 GHz. It is within 2%, preferably within ± 1% at an applied frequency of 100 MHz, and preferably within ± 0.5% at an applied frequency of 10 MHz in other embodiments. The metal fiber sheet of the present embodiment can have the same conductivity as the solid material as long as the difference in transmission attenuation rate is at least ± 5% or less. However, the smaller the difference in transmission attenuation rate, the more preferable it is because the same conductive performance as that of the solid material can be exhibited. The transmission attenuation rate difference can be calculated by the following formula.
(Transmission attenuation rate difference) = (Transmission attenuation rate of the metal fiber sheet of the present embodiment)-(Transmission attenuation rate of a solid material having the same composition as the metal fiber sheet of the present embodiment)

For example, when the metal fiber sheet of the present embodiment is a copper fiber sheet containing only copper fibers, examples of the solid material having the same composition as the metal fiber sheet of the present embodiment include copper pieces, copper plates, and copper foils. .. When the metal fiber sheet of the present embodiment is an aluminum fiber sheet containing only aluminum fibers, examples of the solid material having the same composition as the metal fiber sheet of the present embodiment include an aluminum piece, an aluminum plate, and an aluminum foil. Be done. When the metal fiber sheet of the present embodiment contains 50% by mass of copper fibers and 50% by mass of aluminum fibers with respect to 100% by mass of the metal fiber sheet, it has the same composition as the metal fiber sheet of the present embodiment. Examples of the solid material include a metal piece, a metal plate, and a metal foil composed of 50% by mass of a copper component and 50% by mass of an aluminum component with respect to 100% by mass of the solid material.
When the metal fiber sheet of the present embodiment contains a material other than metal such as resin, a material having the same composition as the metal material excluding non-metal material such as resin may be used as the solid material.

The thermal conductivity of the metal fiber sheet of the present embodiment is 150 W / m · K or less, preferably 100 W / m · K or less. The lower limit of the thermal conductivity is not particularly defined as long as the effect of the present invention is not impaired, but 10 W / m · K or more can be used as a guide. When the thermal conductivity of the metal fiber sheet is at least 150 W / m · K or less, the heat transfer property of the metal fiber sheet of the present embodiment can be reduced.
In the metal fiber sheet of the present embodiment, since the fibers contained in the metal fiber sheet of the present embodiment are bonded to each other at least in part, a gap can be provided between the copper fibers. Such voids may be formed, for example, by entanglement of copper fibers. The presence of such voids can reduce the heat transfer property of the metal fiber sheet. The porosity of the metal fiber sheet of the present embodiment is preferably 35% to 95%, more preferably 40% to 90%. If the porosity is less than 35%, the thermal conductivity tends to increase, and the heat transfer property of the metal fiber sheet of the present embodiment may increase.

In the metal fiber sheet of the present embodiment, it is preferable that the fibers contained in the metal fiber sheet of the present embodiment are bonded to each other by sintering. Since the fibers are bonded to each other by sintering, the conductivity, thermal conductivity, and homogeneity of the metal fiber sheet of the present embodiment can be easily stabilized.

The average fiber diameter of the copper fiber or the aluminum fiber according to the present embodiment can be arbitrarily set within a range that does not impair the transmission attenuation rate and the thermal conductivity of the metal fiber sheet. The average fiber diameter of the copper fiber or the aluminum fiber is preferably 1 μm to 100 μm, and preferably 15 μm to 50 μm. If the average fiber diameter of the copper fiber or the aluminum fiber is less than 1 μm, the rigidity of the fiber is lowered, and so-called lumps tend to occur when the metal fiber sheet is produced. If the average fiber diameter of the copper fiber or aluminum fiber exceeds 100 μm, the rigidity of the fiber may hinder the fiber entanglement.
The shape of the cross section perpendicular to the longitudinal direction of the copper fiber or the aluminum fiber can be any shape. The shape of such a cross section may be any shape such as a circular shape, an elliptical shape, a substantially quadrangular shape, and an indeterminate shape.

The average fiber length of the copper fiber or the aluminum fiber according to the present embodiment can be arbitrarily set within a range that does not impair the transmission attenuation rate and the thermal conductivity of the metal fiber sheet, but is in the range of 1 mm to 30 mm. It is preferably in the range of 3 mm to 10 mm, and more preferably in the range of 3 mm to 10 mm. If the average fiber length of the copper fiber or aluminum fiber is in the range of 1 mm to 30 mm, for example, when the metal fiber sheet of the present embodiment is produced by fabrication, fiber lumps are less likely to occur and the fibers are highly dispersed. In addition to being easy to control, the handling strength of the metal fiber sheet is likely to be improved by the entanglement of the fibers.

The copper fiber or aluminum fiber according to the present embodiment is a long copper fiber or a long copper fiber when the long copper fiber or the long aluminum fiber produced by a melt spinning method, a drawing method or the like is cut to a desired length. Since aluminum fibers are fine, it is not realistic to cut the fibers one by one. Therefore, it is preferable to adopt a method of bundling and cutting long copper fibers or long aluminum fibers. When the long copper fibers or the long aluminum fibers are bundled and cut, it is preferable to sufficiently loosen the bundle of the long copper fibers or the long aluminum fibers before cutting. By sufficiently loosening the bundle of fibers, it becomes easy to suppress the phenomenon that the cut surfaces between the fibers stick to each other at the time of cutting. It is preferable that the fibers do not stick to each other on the cut surface and each of the copper fibers or aluminum fibers behaves independently. This facilitates excellent homogeneity, low transmission attenuation, and low heat transfer of the metal fiber sheet. In particular, copper fibers and aluminum fibers have low hardness, so it is effective to adopt the above-mentioned method.

The aspect ratio of the copper fiber or aluminum fiber according to this embodiment is preferably 33 to 10,000. When the aspect ratio is less than 33, so-called lumps are unlikely to occur, but fiber entanglement is unlikely to occur, so that the conductivity may decrease. When the aspect ratio exceeds 10,000, the handling strength is sufficiently maintained, but lumps are likely to occur, and the homogeneity of the metal fiber sheet may decrease.

The space factor of the metal fiber sheet of the present embodiment is preferably in the range of 5% to 65%, more preferably 10% to 60%. If the space factor is less than 5%, the amount of fibers is insufficient, so that the homogeneity may decrease and the transmission attenuation rate may increase. If the space factor exceeds 65%, the flexibility of the metal fiber sheet may decrease and the heat transfer property may increase.
The thickness of the metal fiber sheet of the present embodiment can be adjusted to any thickness, but is preferably in the range of, for example, 20 μm to 5 mm.

The metal fiber sheet of the present embodiment preferably has a coefficient of variation (CV value) of the basis weight specified in JIS Z8101 per ^{cm 2 of 10% or less.} Since the basis weight is an index showing the weight per unit area, the coefficient of variation of the basis weight is less than a certain value, that is, the space factor, the transmission attenuation factor (conductivity), and the thermal conductivity of each piece. It can be said that is also a stable value. That is, when the fluctuation coefficient of the basis weight of the metal fiber sheet of the present embodiment is 10% or less, there are no lumps or voids of extreme size in the metal fiber sheet, and the space factor and conductivity of the metal fiber sheet are not present. , And the value of thermal conductivity also tends to be sufficiently homogeneous.

The coefficient of variation of the basis weight can be obtained by, for example, the method shown below.
1. 1. By cutting the metal fiber sheet to be measured in ^two corners 1 cm, to obtain a metal fiber sheet pieces.
2. 2. Each of the above pieces is weighed with a high-precision analytical balance (for example, "BM-252" manufactured by A & I Co., Ltd.), and the mass of each piece is measured.
3. 3. Considering the possibility that the individual pieces are not cut into strict squares, the distance near the center of two parallel sides is measured, and the measured values are vertically long and horizontally long.
4. The area of each piece is calculated from the vertically long and horizontally long pieces.
5. The basis weight of each piece is calculated by dividing the mass by the area.
6. Divide the standard deviation of the basis weight of all pieces by the average value and multiply by 100 to calculate the coefficient of variation (CV value) of the basis weight of each piece of metal fiber sheet.
The coefficient of variation can be stabilized by measuring, for example, 100 or more pieces. Further, when the metal fiber sheet to be measured is less than 1 cm ² can be a varying value converted to 1 cm ² coefficient (CV value).

The metal fiber sheet of the present embodiment is not limited in thickness, area, etc., and can be appropriately changed depending on the intended use. Further, the metal fiber sheet of the present embodiment may be, for example, a form in which a plurality of sheets are stacked or a form in which a plurality of sheets are laminated and sintered. Furthermore, an insulating coating can be applied if necessary.

Hereinafter, an example of the method for manufacturing the metal fiber sheet of the present embodiment will be described.
Examples of the method for obtaining the metal fiber sheet of the present embodiment include a dry method of compression-molding a web mainly composed of copper fiber or aluminum fiber, copper fiber or aluminum fiber, and copper fiber or aluminum fiber, or copper fiber or aluminum fiber. Examples thereof include a method of making paper by a wet making method for a raw material mainly composed of.
When the metal fiber sheet of the present embodiment is obtained by the dry method, the copper fiber or aluminum fiber obtained by the card method, the airlaid method, or the like, or the web mainly composed of copper fiber or aluminum fiber can be compression-molded. it can. At this time, the copper fiber or the aluminum fiber may be impregnated with the binder in order to bond the fibers. The binder is not particularly limited, and examples thereof include organic binders such as acrylic adhesives, epoxy adhesives, and urethane adhesives, and inorganic adhesives such as colloidal silica, water glass, and sodium silicate. Can be used. Instead of impregnating the binder, the surface of the fiber is coated with a heat-adhesive resin in advance, and copper fiber or aluminum fiber, or an aggregate mainly composed of copper fiber or aluminum fiber is laminated and laminated. The laminated body may be pressurized and compressed by heating.

The metal fiber sheet of the present embodiment can also be produced by a wet manufacturing method in which copper fibers, aluminum fibers, or the like are dispersed in water, and the copper fibers, aluminum fibers, or the like dispersed in water are produced. Specifically, for example, first, a stirring mixer is used to prepare a slurry mainly composed of copper fibers or aluminum fibers. Next, known additives such as fillers, dispersants, thickeners, defoamers, paper strength enhancers, sizing agents, coagulants, colorants, and fixing agents can be appropriately added to the slurry. ..

Slurries of polyethylene terephthalate (PET) resin, polyvinyl alcohol (PVA), polyethylene, and polyolefins such as polypropylene, polyvinyl chloride resin, aramid resin, nylon, and acrylic resin as fibrous materials other than copper fiber and aluminum fiber. It can also be added to. These copper fibers and organic fibers other than aluminum fibers exhibit binding properties by heating and melting, and can assist the morphological maintenance of the metal fiber sheet. However, when a binding portion is provided between the fibers by sintering, it is preferable to perform sintering in the absence of organic fibers or the like to surely provide the binding portion.

When making copper fibers or aluminum fibers in the absence of organic fibers as described above, agglomerates such as so-called lumps are formed due to the difference in true density between water and fibers and the over-entanglement of fibers. It is easy to occur. Therefore, it is preferable to use a thickener or the like as appropriate. Further, in the slurry in the stirring mixer, copper fibers or aluminum fibers having a high true density tend to settle on the bottom surface of the mixer. Therefore, it is preferable to use the slurry excluding the vicinity of the bottom surface as the papermaking slurry.

Next, using the above slurry, wet papermaking is carried out with a paper machine. As the paper machine, a circular net paper machine, a long net paper machine, a short net paper machine, an inclined paper machine, and a combination paper machine obtained by combining the same type or different types of paper machines can be used. .. Next, the wet paper after papermaking is dried using an air dryer, a cylinder dryer, a suction drum dryer, an infrared dryer, or the like to obtain the sheet of the present embodiment.

When the metal fiber sheet of the present embodiment is manufactured by a wet papermaking method, copper fibers or aluminum fibers that form a wet body sheet containing moisture on the papermaking net, or components mainly composed of copper fibers or aluminum fibers are used. A fiber entanglement treatment step of entwining with each other may be carried out. As the fiber entanglement treatment step, for example, it is preferable to adopt a fiber entanglement treatment step of injecting a high-pressure jet water flow onto the wet body sheet surface. Specifically, a plurality of nozzles are arranged in a direction orthogonal to the sheet flow direction. Then, by injecting a high-pressure jet water stream from the plurality of nozzles at the same time, the fibers can be entangled with each other over the entire sheet. After passing through this step, the wet body sheet is wound up through a dryer step and the like.

The metal fiber sheet of the present embodiment produced through the above-mentioned fiber entanglement treatment step may be subjected to a press (pressurization) step before binding the fibers to each other, for example. By carrying out the pressing step before the binding, the binding portion can be surely provided between the fibers in the subsequent binding step, and the conductivity and homogeneity of the metal fiber sheet can be easily improved.
The pressing step may be carried out under heating or under non-heating. When the metal fiber sheet of the present embodiment contains an organic fiber or the like that exhibits binding properties by heating and melting, it is effective to heat the organic fiber or the like at a temperature equal to or higher than the melting start temperature. When the metal fiber sheet of the present embodiment contains only metal fibers, only pressurization may be performed.
The pressure in the pressing process can be appropriately set in consideration of the thickness of the metal fiber sheet. For example, when the pressing process is performed on a metal fiber sheet having a thickness of about 170 μm, the pressing process is performed at a linear pressure of less than 300 kg / cm, preferably less than 250 kg / cm, so that low transmission to the metal fiber sheet of the present embodiment is performed. It is possible to easily impart the attenuation rate and homogeneity. By the pressing process, the space factor and the porosity of the metal fiber sheet of the present embodiment can be adjusted.

As a method of binding the fibers of the metal fiber sheet of the present embodiment, a method of sintering the metal fiber sheet, a method of binding by chemical etching, a method of laser welding, and a method of binding using IH heating are used. , Chemical bond method, and other known thermal bond methods can be used. Among these, the method of sintering the metal fiber sheet can surely bind the fibers contained in the metal fiber sheet to each other and fix the fibers between the fibers, and the transmission attenuation rate and heat conduction of the metal fiber sheet can be fixed. It is preferable because the fluctuation coefficient (CV value) of the rate and the basis weight becomes stable easily.

In order to sinter the metal fiber sheet, it is preferable to go through a sintering step of sintering at a temperature equal to or lower than the melting point of the metal fiber in a vacuum or a non-oxidizing atmosphere. In the metal fiber sheet that has undergone the sintering process, the fibers contained in the metal fiber sheet are bonded to each other by sintering. As described above, when a binding portion is provided between the metal fibers by sintering, it is preferable to sinter in the absence of organic fibers or the like. By carrying out the sintering process, even if the sheet is composed of only metal fibers, the contacts of the metal fibers are bonded to each other, and the bonded portion can be surely provided, and the transmission damping factor (conductivity) is low. ), And the homogeneity is easy to stabilize.

The metal fiber sheet that has undergone the sintering step is preferably further subjected to the pressing step. By going through the pressing process after the sintering process, the conductivity and homogeneity of the metal fiber sheet can be further improved. For example, when the metal fiber sheet is a non-woven fabric of metal fibers, the non-woven fabric in which the metal fibers are randomly entangled causes a fiber shift not only in the thickness direction but also in the surface direction by pressing. As a result, the fibers are easily arranged even in the places that were voids at the time of sintering, and such a state is maintained by the plastic deformation characteristics of the copper fibers, the aluminum fibers, and the like.
The pressure in the pressing step performed after the sintering step can be appropriately set in consideration of the thickness of the metal fiber sheet.

The metal fiber sheet of the present embodiment can be produced by the above-mentioned method. The transmission attenuation rate and the thermal conductivity of the metal fiber sheet are determined by adjusting the space factor, the void ratio, the thickness of the metal fiber sheet, the bulk density of the copper fiber or the aluminum fiber, and the like. Can be adjusted to a value.

In the metal fiber sheet of the present embodiment described above, the fibers contained in the metal fiber sheet are bonded to each other at least in part, and the difference in transmission attenuation rate from the solid material is within ± 5%. , Has the same conductivity as conventional solid materials. Further, the metal fiber sheet of the present embodiment has voids between the copper fibers and has a thermal conductivity of 150 W / m · K or less, so that the heat transfer property is low.

[Wiring member]
Hereinafter, the wiring member of the present embodiment will be described, but the wiring member of the present invention is not limited to the following description.
The wiring member of this embodiment is a wiring member using the metal fiber sheet of this embodiment. That is, the wiring member of the present embodiment is a wiring member manufactured by using the metal fiber sheet of the present embodiment as the material of the conductor.

The wiring member of this embodiment can be used as a conductive path in an electric circuit. For example, the wiring member of the present embodiment can be used by adding a known configuration such as an element, a terminal, a covering material, and an insulator, and can also be provided with a known cooling mechanism used in the wiring member. ..

The wiring member of this embodiment can be used, for example, in a high frequency heating coil used in a glass melting furnace in the nuclear power field. Generally, when a high-frequency current is applied to a wiring member, the current density on the surface of the conductor increases due to the skin effect, and the higher the frequency, the more the current concentrates on the surface of the conductor, and the AC resistance of the conductor tends to increase.
In the wiring member of the present embodiment, since the conductor is made of a metal fiber sheet, a difference in current density is less likely to occur between the surface portion and the central portion of the metal fiber as compared with the wiring member using a solid material, and the conductor. AC resistance is unlikely to increase.

In addition to the above examples, the wiring member of the present embodiment can be used, for example, as a wiring member for supplying power to a plasma processing apparatus in the semiconductor field, and can be used for a bus bar or the like in the automobile field. Hereinafter, the wiring member for supplying power to the plasma processing apparatus in the semiconductor field will be described, and the bus bar in the automobile field will be described in the section “[Bus bar]” of the present embodiment described later.

[Wiring member for power supply of plasma processing device]
The wiring member of this embodiment can be used as a wiring member for supplying power to a plasma processing apparatus using a high frequency power supply.
FIG. 1 is a cross-sectional view showing an example of a plasma processing apparatus 10 including wiring members 2a and 2b according to an embodiment to which the present invention is applied. As shown in FIG. 1, the plasma processing apparatus 10 includes an electrode 1a (1b), a wiring member 2a (2b), an AC power supply 3a (3b), and a vacuum vessel 4.

The electrode 1a and the electrode 1b are housed in the vacuum container 4. The electrodes 1a (1b) are connected to the AC power supply 3a (3b) via the wiring member 2a (2b).
By energizing the electrode 1b with a high-frequency current, a thin film such as a wafer W can be formed from the process gas supplied to the vacuum vessel 4.

The wiring member 2a (2b) is provided between the electrode 1a (1b) and the AC power supply 3a (3b). The wiring member 2a (2b) electrically connects the electrodes 1a (1b) and the AC power supply 3a (3b).

The wiring member 2a (2b) is provided so as to cover the surface of the rod body 6a (6b).
The rod body 6a (6b) has a first end connected to the electrode 1a (1b) and a second end connected to the AC power supply 3a (3b). The rod body 6a (6b) is supported by the AC power supply 3a (3b).
The wiring member 2a (2b) can electrically connect the electrodes 1a (1b) and the AC power supply 3a (3b), and supply electric power to the electrodes 1a (1b) from the AC power supply 3a (3b).

The electrodes 1a (1b) of the plasma processing apparatus configured as described above may have a high temperature of 300 ° C. or higher when forming a thin film such as a wafer W. The AC power supply 3a (3b) is easily affected by heat, and the heat is likely to cause problems such as failure. Therefore, the plasma processing device 10 supplies electric power from the AC power supply 3a (3b) to the electrodes 1a (1b) via the wiring members 2a (2b).
The rod body 6a (6b) is provided with a hollow flow path 5a (5b) through which a refrigerant such as air flows, inside the rod body 6a (6b). The flow path 5a (5b) is provided for the purpose of cooling the wiring member 2a (2b) and the electrode 1a (1b) that generate heat by energization.

Since the wiring member 2a (2b) is manufactured by using the metal fiber sheet of the present embodiment, the thermal conductivity is lower than that of the wiring member manufactured by using the solid material. Therefore, for example, the heat generated in the high temperature portion such as the electrodes 1a (1b) is unlikely to be transferred to the surrounding equipment such as the AC power supply 3a (3b). Further, since the wiring member of the present embodiment is manufactured by using the metal fiber sheet of the present embodiment, it can have the same conductivity as the wiring member using the solid material.

Since the wiring member 2a (2b) uses the metal fiber sheet of the present embodiment, it is difficult to transfer the heat generated by the high-temperature electrode to the surrounding equipment. Therefore, even if the electrode is energized using a high current value or high frequency and the electrode further generates heat, it is difficult to transfer heat to the surrounding device portion such as the power supply. Further, since the wiring member 2a (2b) uses the metal fiber sheet of the present embodiment, the same electric power as that of the wiring member using the solid material can be supplied to the electrodes 1a (1b).
Therefore, according to the wiring member of the present embodiment, it is possible to energize the electrode by using a high current value or a high frequency that cannot be achieved by the solid material.

In addition to the above-described configuration, the plasma processing apparatus 10 can be provided with known configurations such as a supply pipe for supplying the process gas to the vacuum vessel 4 and a discharge pipe for discharging the process gas from the vacuum vessel 4.

The process gas supplied from the supply pipe to the vacuum vessel is used for the formation reaction of the wafer W and is discharged from the exhaust pipe. For example, the larger the area of the electrode 1b, the easier it is for the productivity of the wafer W to improve. If the area of the electrode 1b is increased here, it is necessary to energize the electrode 1b (1a) with a higher current value.

Since the plasma processing device 10 includes the wiring members 2a (2b), the electrodes can be energized with a higher current value. Therefore, according to the plasma processing apparatus 10, it is possible to improve the productivity of plasma processing such as thin film formation.

In the wiring member of the present embodiment, for example, a plurality of metal fiber sheets of the present embodiment may be laminated, or a plurality of metal fiber sheets may be laminated and sintered. Furthermore, an insulating coating can be applied if necessary.

[Busbar]
FIG. 2 is a diagram for explaining a bus bar in the automobile field. Specifically, FIG. 2 is a schematic diagram showing an example of an electric circuit of a drive system of an electric vehicle. As shown in FIG. 2, the electric circuit 20 is roughly configured with a battery unit 11, a refrigerant flow path 15, and a chiller 16.

As shown in FIG. 2, the battery unit 11 is roughly configured with a battery 12, a bus bar 13 of the present embodiment, and a fuse 14.
The battery unit 11 is for supplying electric power to a drive motor or the like (not shown) included in an electric vehicle. The battery unit 11 is connected to a drive motor or the like via a contactor (not shown). In the battery unit 11, the battery 12, the bus bar 13, the fuse 14, and the contactor (not shown) are connected in this order. That is, in the battery unit 11, the bus bar 13 is provided between the battery 12 and the fuse 14. Although only one battery 12 is shown in FIG. 2, the battery unit 11 may include a plurality of batteries 12.

The battery unit 11 includes the bus bar 13 of the present embodiment as a conductive path.
Since the bus bar 13 of the present embodiment uses the metal fiber sheet of the present embodiment, it has the same conductivity as the conventional bus bar. Therefore, the battery unit 11 can supply electric power equivalent to that of the conventional bus bar.
Since the bus bar 13 of the present embodiment uses the metal fiber sheet of the present embodiment, the thermal conductivity is lower than that of the conventional bus bar using a solid material. Therefore, for example, the heat generated by the fuse 14 or the like is unlikely to be transferred to the surrounding members such as the battery 12 via the bus bar 13. Therefore, the battery unit 11 can prevent deterioration of the battery 12 due to heat generated by the fuse 14.
Therefore, from the above, according to the bus bar of the present embodiment, the battery unit 11 is less likely to be limited by the current value due to heat generation, so that the battery unit 11 can be energized with a high current value that cannot be achieved by the solid material.

The chiller 16 can cool the battery unit 11 via the refrigerant flow path 15.
The refrigerant flow path 15 is connected to the chiller 16. In the electric circuit 20, the refrigerant flowing through the refrigerant flow path 15 can circulate around the battery 12, around the bus bar 13, or inside the bus bar 13. When introducing or circulating the refrigerant in the refrigerant flow path 15, for example, a pump (not shown) may be used. The refrigerant used in the present embodiment may be, for example, a known refrigerant such as a fluorine-based inert liquid and an insulating liquid such as insulating oil, or a gas such as air.

The bus bar 13 uses the metal fiber sheet of the present embodiment. The metal fiber sheet of the present embodiment can have voids formed by the metal fibers on the inner surface of the sheet. Therefore, the surface area of the outer surface and the surface area of the inner surface of the metal fiber sheet can be widened, and the cooling effect of the refrigerant tends to be enhanced. Therefore, in the electric circuit 20, the refrigerant flow path 15 can be formed inside the bus bar 13. Since the refrigerant flow path 15 is formed inside the bus bar 13, the inside of the bus bar 13 can be effectively cooled.

Even if the refrigerant flow path 15 is not formed inside the bus bar 13, a flow path for air or the like is secured inside the bus bar 13 by the voids provided in the metal wire sheet. Therefore, in the electric circuit 20, the cooling effect of the refrigerant bar 13 is likely to be enhanced regardless of whether or not the refrigerant flow path 15 is formed inside the bus bar 13.

As described above, since the electric circuit 20 includes the refrigerant flow path 15 and the chiller 16, the cooling effect of the bus bar 13 can be enhanced. Therefore, the electric circuit 20 can improve the low heat transfer property of the bus bar 13. Further, the electric circuit 20 can energize the bus bar 13 with a higher current value by making the low heat transfer property of the bus bar 13 better.

The bus bar of the present embodiment may be, for example, a mode in which a plurality of metal fiber sheets of the present embodiment are stacked, or a mode in which a plurality of sheets are laminated and sintered. Furthermore, an insulating coating can be applied if necessary.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to the following description.

(Example 1)
Copper fibers having a fiber diameter of 18.5 μm, an average fiber length of 3 mm, and a substantially annular cross-sectional shape were dispersed in water, a thickener was appropriately added, and the mixture was stirred with a mixer to prepare a papermaking slurry. The portion of the bottom of the mixer having a high copper fiber concentration was removed from this papermaking slurry. Then, using the papermaking slurry, the paper ^{was put on a papermaking net with a basis weight of 300 g / m 2} as a guide, and dehydrated and dried to obtain a copper fiber non-woven fabric. Then, the non-woven fabric is pressed at a linear pressure of 80 kg / cm at room temperature and then heated at 1020 ° C. for 40 minutes in an atmosphere of 75% by mass of hydrogen gas and 25% by mass of nitrogen gas to sinter the copper fibers. The copper fiber sheet of Example 1 was obtained. The thickness of the obtained copper fiber non-woven fabric was 240 μm.
Next, the obtained copper fiber sheet was cut into 24 cm × 18 cm, cut into 1 cm ² at the dotted line portion in the mapping diagram of FIG. 3, and divided into 1 to 24 and A to S (excluding I), for a total of 432. Obtained pieces. From the mass of this piece and the measured value of the area, the basis weight of each piece was calculated. The coefficient of variation of the basis weight calculated from the standard deviation and the average value of all the pieces was 4.5, and the average void ratio was 86.0%.

(Example 2)
Similar to Example 1, the thickness is 124 μm and the average porosity is 45, except that the basis weight is 600 g / m ^{2 and the thickness is pressed with a load of 700 kg / cm after sintering.} A 9.9% copper fiber sheet of Example 2 was obtained. The coefficient of variation of the basis weight calculated by the same method as in Example 1 was 5.9.

(Example 3)
A copper fiber sheet of Example 3 having a thickness of 496 μm and an average porosity of 85.7% was obtained in the same manner as in Example 2 except that the copper fiber sheet was not pressed in the thickness direction after sintering. The coefficient of variation of the basis weight calculated by the same method as in Example 1 was 6.8.

(Example 4)
A copper fiber sheet of Example 4 having a thickness of 104 μm and an average porosity of 67.7% was obtained in the same manner as in Example 1 except that it was pressed with a load of 220 kg / cm in the thickness direction after sintering. The coefficient of variation of the basis weight calculated by the same method as in Example 1 was 4.1.

(Comparative Example 1)
A 100 μmt copper foil was used as Comparative Example 1. The copper foil is a solid material.

(Comparative Example 2)
A 100 μmt aluminum foil was used as Comparative Example 2. The aluminum foil is a solid material.

The transmission attenuation and thermal conductivity of the copper fiber sheets obtained in each example were measured according to the following description. The measurement results are shown in Table 1.

(Transmission attenuation rate)
The transmission attenuation factor was measured based on the evaluation method of the noise suppression sheet specified in IEC-62333. Specifically, a transmission line with a characteristic impedance of 50Ω is made of copper foil on a substrate material with a ground surface (“CGP-500A” manufactured by Chuko Kasei Kogyo Co., Ltd.), and this is manufactured by a network analyzer (Agilent Technology Co., Ltd. “CGP-500A”). It was connected to PNA-L N5230C) with a connector, the S parameter was measured in the frequency range of 10 MHz to 10 GHz, and it was calculated from the reflection coefficient | S ₁₁ | and the transmission coefficient | S ₂₁ | by the following formula.
(Transmission attenuation rate (%)) = 1- (| S ₁₁ | ² + | S ₂₁ | ² ) x 100
Here, | S ₁₁ | is a reflection coefficient (reflected power / input power to the transmission line), and | S ₂₂ | is a transmission coefficient (output power / input power to the transmission line). The metal on the ground surface was changed to each metal sheet shown in Examples and Comparative Examples, and the effect on the transmission attenuation rate was evaluated.
The relationship between the applied frequency and the transmission attenuation factor is shown in FIG.

(Casa density)
It was calculated from the basis weight and thickness of the sample by the following formula.
(Casa density (kg / m ³ )) = (Basis weight (g / m ² ) / Thickness (μm) x 1000)
From the obtained thermal diffusivity, specific heat capacity, and bulk density, the thermal conductivity is calculated by the following formula.
(Thermal conductivity (W / (m · K))) = (Thermal diffusivity (m ² / sec)) × (Specific heat capacity (J / (K · kg)) × (Bass density (kg / m ² )))

(Thermal conductivity)
The thermal diffusivity in the in-plane direction of the metal sheet of each example was measured by the optical exchange method, and the thermal conductivity was calculated by multiplying the specific heat capacity and bulk density of the metal sheet. Specifically, a carbon spray is applied to the metal sheet of each example as a sample to blacken it, and it is set in an optical diffusivity measuring device (“LaserPIT” manufactured by Advance Riko Co., Ltd.) at room temperature, 0.01 Pa. The thermal diffusivity was measured at a frequency of 2.5 Hz of laser heating light under the following reduced pressure atmosphere.
Next, an empty container, a weighed sample, and a standard sample (sapphire) having a known weight and specific heat capacity are placed in a DSC (“DSC6200” manufactured by Seiko Instruments) in a nitrogen atmosphere at a heating rate of 10 ° C./min. The specific heat capacity of the sample was calculated from the calorific value absorbed and generated in the range of 10 ° C. to 250 ° C.
The relationship between the porosity and the thermal conductivity is shown in FIG.

As shown in Table 1, the difference in transmission attenuation of the copper fiber sheets of Examples 1 to 3 from the solid material was 5% or less at each applied frequency (10 MHz, 100 MHz, 1 GHz, 10 GHz). Further, as shown in FIG. 4, the behavior of the transmission attenuation of the copper fiber sheets of Examples 1 to 3 with respect to the applied frequency is almost the same as the behavior of the transmission attenuation of the metal sheets of Comparative Examples 1 and 2. It turned out to do. From the above, it was found that the copper fiber sheets of Examples 1 to 3 have the same or higher conductivity than the solid material.

As shown in Table 1, the thermal conductivity of the copper fiber sheets of Examples 1 and 2 was 150 W / m · K or less, respectively. On the other hand, the thermal conductivity of Comparative Examples 1 and 2 exceeded 150 W / m · K. Further, as shown in FIG. 5, it was found that the higher the porosity of the copper fiber sheet of the example, the lower the thermal conductivity. From the above, it was found that the copper fiber sheets of Examples 1 and 2 had lower heat transfer properties than the solid material.

1 Electrode 2 Wiring member 3 AC power supply 4 Vacuum vessel 5 Flow path 6 Rod body 10 Plasma processing device 11 Battery unit 12 Battery 13 Bus bar 14 Fuse 15 Refrigerant flow path 16 Chiller 20 Electric circuit

Claims (4)

Metal fiber sheet der consisting of a copper fiber is,
The fibers contained in the metal fiber sheet are bonded to each other at least in part.
The difference in transmission attenuation calculated by the following method between the metal fiber sheet and the solid material having the same composition is within ± 5%.
A metal fiber sheet having a thermal conductivity of 150 W / m · K or less.
Calculation method of transmission attenuation factor difference: The transmission attenuation factor (%) is measured within a frequency range of 10 MHz to 10 GHz for each of the metal fiber sheet having a size of 100 mm × 50 mm and the solid material having a size of 100 mm × 50 mm. Calculate the transmission attenuation factor difference (%). The metal fiber sheet according to claim 1, wherein the fibers are bonded to each other by sintering. A wiring member using the metal fiber sheet according to claim 1 or 2. A bus bar using the metal fiber sheet according to claim 1 or 2.

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