JP2008007792A - Method for producing composite metal foil, composite metal foil, formed metal foil and method for producing formed metal foil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide composite metal foil suitable for the microfabrication of rugged shape and whose productive efficiency is improved, to provide a method for producing composite metal foil, to provide formed metal foil, and to provide a method for producing formed metal foil. <P>SOLUTION: In the production of composite metal foil and formed metal foil with rugged shape, a production method including: a stage where rugged shape corresponding to the rugged shape of the composite metal foil and formed metal foil to be produced is formed on the surface of a carrier base material; and a stage where a coating metal layer is formed along the surface of the carrier base material with the rugged shape formed using a vapor deposition process is adopted. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a composite metal foil having an uneven shape, a composite metal foil made by the manufacturing method, a molded metal foil having an uneven shape, and a method for manufacturing the formed metal foil.

  The metal foil with uneven shape is made to correspond to the desired shape when a conduction path or space is required, such as a fuel cell separator, buffer material, environmental purification filter, exhaust gas purification carrier, or when a larger surface area is required. It is used in various fields such as machinery, building materials and electronic equipment parts. As a material of the metal foil used for the said use, what was lightweight and excellent in corrosion resistance, such as stainless steel, nickel, and titanium, is used. For example, Patent Document 1 discloses a method of manufacturing a corrosion-resistant metal clad material for a separator. A coating layer is formed on both surfaces of a core material by a cold rolling method, and the coating layer is rolled several times to obtain a thickness. After adjusting the thickness, a separator using a corrosion-resistant metal clad material for a separator in which a hydrogen supply passage and an oxygen supply passage are formed by a press method is disclosed. Among these metals with excellent corrosion resistance, titanium-based metals have high strength, light weight and stable corrosion resistance, so secondary battery separators, small heat sinks, etc. that require performance such as small size, light weight and long life It is particularly attracting attention as an application of.

JP 2005-2411 A

  As disclosed in Patent Document 1, the technique of forming a metal foil by a pressing method is unsuitable for processing fine concavo-convex shapes. Moreover, since the metal foil shape | molded by the press method has many manufacturing processes, the point with a large manufacturing cost has been a subject. Further, the manufacturing loss caused by adding physical effects other than heating and cooling in the manufacturing process to the manufactured product increases the possibility that the larger the number of processes, the higher the manufacturing efficiency. Therefore, the present invention provides a method for producing a composite metal foil, a composite metal foil, a formed metal foil, and a formed metal foil that are suitable for processing titanium and the like, which can process a fine shape and improve manufacturing efficiency. The purpose is to provide.

  As a result of intensive studies, the present inventors have achieved the above object by employing the following manufacturing method. Hereinafter, the method for producing a composite metal foil and a molded metal foil, and the composite metal foil and the molded metal foil produced by this production method will be described separately.

<Production method of composite metal foil>
The manufacturing method of the composite metal foil which concerns on this invention is a manufacturing method of composite metal foil provided with an uneven surface, Comprising: The following processes A-C are included, It is characterized by the above-mentioned.
Step A: A step of forming, on the surface of the carrier substrate, a protruding resist pattern that becomes a mold for forming the same uneven shape on the surface of the carrier substrate as the uneven shape provided for the composite metal foil.
Step B: After embedding plating using an electrolytic plating method in a resist recess formed by the surface of the carrier substrate and the protruding resist pattern, the protruding resist pattern is removed and the surface of the carrier substrate The process which makes a carrier base material provided with an uneven | corrugated shape on the surface by forming a projection part in this.
Step C: A step of forming a coated metal layer on the surface of the carrier base material on which the concavo-convex shape is formed by using a vapor phase growth method to obtain a composite metal foil having the concavo-convex shape.

  And in the manufacturing method of the said composite metal foil, it is preferable that the said process A forms a resist layer on the surface of a carrier base material, and forms the said protruding resist pattern on the carrier base material surface by a photomask method.

  In the method for producing a composite metal foil according to the present invention, the vapor phase growth method is preferably either a sputtering vapor deposition method or an electron beam vapor deposition method.

  Furthermore, in the manufacturing method of the composite metal foil according to the present invention, in the carrier base material having the concavo-convex shape, the side wall surface in the cross section of the protruding portion formed on the surface of the carrier base material is between the side wall surface and the protruding portion. It is preferable that the angle formed with the surface of the carrier substrate exposed to the surface of the carrier has an inclination in the range of 90 ° to 135 °.

  Moreover, in the manufacturing method of the composite metal foil which concerns on this invention, it is preferable that the height which the protrusion part formed in the said carrier base material protrudes is 10 micrometers-50 micrometers.

<Composite metal foil>
The composite metal foil according to the present invention is a composite metal foil provided with a coated metal layer along a concavo-convex shape provided on the surface of a carrier substrate, and is obtained using the above-described method for manufacturing a composite metal foil. .

  The coated metal layer of the composite metal foil according to the present invention is composed of any one of titanium, tantalum, niobium, or an alloy thereof (hereinafter referred to as “metal composed of titanium or the like”). preferable.

  The alloy of titanium, tantalum, and niobium includes at least one of titanium, tantalum, and niobium, and the composition of the components is not limited as long as other metal components are included in an arbitrary ratio. This is because a wide range of composition combinations can be adopted by changing the target composition in consideration of using the sputtering deposition method. For example, in addition to those containing two or more of titanium, tantalum, and niobium, compositions having one or more of titanium, tantalum, and niobium and metals such as molybdenum, aluminum, and palladium are also conceivable. In sputtering deposition, argon gas is generally used, but when a reactive gas such as oxygen, nitrogen, or carbon is introduced and sputtered, it reacts with the target to form a compound thin film such as an oxide, nitride, or carbide. be able to. Thus, when a reactive gas is introduced and sputtered to form a film, a homogeneous and stable thin film can be formed.

  In the composite metal foil according to the present invention, the covering metal layer preferably has a thickness of 1 μm to 15 μm.

  Furthermore, the composite metal foil according to the present invention preferably has a maximum thickness of 38 μm to 400 μm in cross-sectional observation.

  Moreover, it is preferable that the said uneven | corrugated shape of the composite metal foil which concerns on this invention is 30 micrometers-200 micrometers in the pitch of the carrier recessed part and protrusion part in the cross-sectional observation.

  Furthermore, in the composite metal foil according to the present invention, it is preferable that the protrusions provided on the surface of the carrier base are formed on both sides of the carrier base.

<Molded metal foil>
The molded metal foil according to the present invention is a metal foil obtained by using a composite metal foil having an uneven-shaped coated metal layer on one side of a carrier base material of the above-described composite metal foil, and the carrier of the metal foil It is characterized by being obtained by separating and collecting only the coated metal layer by removing the substrate.

  Moreover, it is preferable that the shaping | molding metal foil which concerns on this invention is 10 micrometers-50 micrometers in thickness.

  And it is preferable that the shaping | molding metal foil which concerns on this invention is comprised by the metal component in any one of titanium, a tantalum, niobium, or these alloys.

  Alternatively, the molded metal foil according to the present invention may have a structure of two or more layers composed of a metal component of any one of titanium, tantalum, niobium or an alloy thereof and a different dissimilar metal. preferable.

<Method for producing molded metal foil>
A method for producing a molded metal foil according to the present invention is a method for producing a metal foil according to any one of the above, wherein a composite metal foil having a concavo-convex-shaped coated metal layer on one side of a carrier substrate is used as a coated metal layer. It is characterized by dipping in a solution capable of selective etching of the constituent metal and the constituent metal of the carrier substrate, and etching away only the metal component of the carrier substrate.

  By using the method for producing a composite metal foil and a molded metal foil according to the present invention, a metal foil having a fine concavo-convex shape that has been difficult to produce can be produced with high accuracy and beauty. Moreover, it can be said that it is a manufacturing method with a high degree of freedom of uneven | corrugated shape and high productivity with few manufacturing processes compared with the manufacturing method of the composite metal foil by the conventional press method.

  Hereinafter, the best mode of the composite metal foil and the molded metal foil according to the present invention and the production method thereof will be described. FIG. 1 is a schematic diagram for explaining steps common to a method for producing a composite metal foil and a method for producing a molded metal foil according to the present invention. First, the feature of the method for producing a composite metal foil and a molded metal foil according to the present invention is that, for example, as shown in FIG. An uneven shape is formed on the surface of the material 2, and a metal film is formed on the surface of the carrier substrate 2 having the uneven shape by a vapor phase growth method. The composite metal foil 1 is a metal foil composed of a carrier substrate 2 and a coating metal layer 9 covering the carrier substrate surface 4, whereas the molded metal foil 10 is formed from the composite metal foil 1 to the carrier substrate. 2 is different in that it consists only of a portion of the coated metal layer 9 obtained by separating and collecting 2. That is, in the manufacturing method of the molded metal foil, after the steps A to C shown in FIGS. 1 (1) to (5), the separation and collection step of the carrier substrate 2 as shown in FIG. 3 (6) is performed. . On the other hand, in the method for producing a composite metal foil, the composite metal foil in which an uneven shape is formed only on one side of the carrier base material 2 by the steps of FIGS. 1 (1) to (5), or as shown in FIG. The other surface where the uneven shape of the composite metal foil having the uneven shape is formed only on one surface illustrated in FIG. 1 (5) is not illustrated, but includes the step of processing to have the uneven shape on both sides. In some cases, a composite metal foil may be obtained through a process such as forming the coated metal layer 9. Hereinafter, the best embodiment will be described in the order of composite metal foil and molded metal foil.

<Production method of composite metal foil>
First, the manufacturing method of the composite metal foil which concerns on this invention is demonstrated along the process A-the process C below.

Step A: In Step A, a protruding resist pattern 6 is formed on the carrier substrate surface 4 to be a mold for forming the same uneven shape on the surface of the carrier substrate 2 as the uneven shape provided for the composite metal foil 1. .

  The protruding resist pattern 6 is a protruding pattern that is formed into a desired shape as a mold for forming an uneven shape on the carrier substrate surface 4 and is non-conductive. For this reason, at the time of electrolytic plating in the subsequent step B, the portion where the protruding resist pattern 6 is formed is not plated up. Therefore, when the embedding plating is performed on the resist concave portion 3 formed by the projecting resist pattern 6 by an electrolytic method, a portion where the projecting resist pattern 6 is formed becomes a mold, and the projecting portion 7 is formed on the carrier substrate surface 4. It is formed.

  The carrier base material 2 is in a foil state or a plate state, and serves as a base in the production of the composite metal foil 1. Further, during electrolytic deposition in the buried plating, the carrier base material 2 is used as a cathode, and a metal element is electrodeposited on the surface to form an uneven shape made of metal plating. For this reason, as long as the material of the carrier base material 2 has electroconductivity, a special material limitation is not necessary. For example, the carrier base material is a metal material that is a foil or plate such as copper, aluminum, or stainless steel, or a material in which the surface of a plastic material is coated with a metal component (for example, a structure in which a metal conductive layer is provided on both sides or one side of a plastic film) Etc.) can be used. In particular, the carrier substrate is preferably a copper foil having a thickness of 18 μm to 380 μm obtained by electrolysis or rolling.

  Here, in the step A, if the following method using a photomask method is used, the protruding resist pattern 6 that realizes refinement, uniform shape, and miniaturization can be smoothly formed. That is, it is preferable to form a resist layer 5 on the carrier base material surface 4 and to form a protruding resist pattern 6 on the carrier base material surface 4 by a photomask method for forming the uneven shape provided in the composite metal foil 1. . The protruding resist pattern 6 may be made of either an etching resist or a plating resist. In the following description, an etching resist is described as an example.

  First, as shown in FIG. 1 (1), a resist layer 5 is formed on the carrier substrate surface 4. The resist layer 5 becomes a resist for plating in a desired position and shape at the time of electrolytic plating for forming protrusions on the surface of the carrier substrate in the subsequent step B. For example, there is a method in which a dry film is disposed on the carrier substrate surface 4 and a dry film as an etching resist (resist layer 5) is attached by a laminator. Here, in order to make it easy to attach a dry film, the carrier base material surface 4 is appropriately processed and then attached using a laminator.

  A dry film is a film having a structure in which a cured resist layer that reacts with light is sandwiched between a polyethylene film and a polyester film, and is widely used as an etching resist for printed wiring boards. This dry film can easily have various variations in thickness, and it is easy to make a wide selection range of the height at which the protruding portion 7 made of metal plating protrudes.

  The resist layer 5 is preferably formed as a photosensitive resist layer using a spin coater or the like, a method using a liquid resist, or the like as a preferable method in addition to the method of forming the above dry film by using a laminator. The method of forming is mentioned. In particular, a liquid resist is advantageous in that it does not generate waste.

  Next, the protruding resist pattern 6 is formed by a photomask method. That is, a photomask having a pattern having the same surface shape as the uneven surface to be produced is placed on or close to the surface of the resist layer 5, and the dry film is exposed and developed by irradiation with ultraviolet rays. Next, an unexposed portion of the photomask pattern was peeled off and removed with a 1% sodium carbonate solution, thereby forming a desired protruding resist pattern 6 as shown in FIG. The protruding resist pattern 6 was formed in a protruding shape on the carrier substrate surface 4 at a position corresponding to the uneven shape formed on the composite metal foil 1. That is, the resist recess 3 is formed by the protruding resist pattern 6 and the carrier substrate surface 4.

  In addition, although the formation method of the convex resist at the time of using a negative type etching resist was shown here, as a photoresist, a desired resist pattern is formed by hardening an etching resist by exposure processing and removing an unnecessary part. Anything can be used.

Step B: In this step B, the embedding plating is performed on the resist concave portion 3 formed by the carrier base material surface 4 and the protruding resist pattern 6 using an electrolytic plating method. Then, the protrusions 7 are formed on the carrier substrate surface 4 by removing the protruding resist pattern 6 after the embedded plating. The protruding resist pattern 6 is removed using a method of dissolving the protruding resist pattern 6 by immersing it in a solution capable of removing a resist component such as an aqueous sodium hydroxide solution. Thereby, the carrier base material 2 is provided with an uneven shape on the surface thereof.

  Here, the front and back surfaces of the composite metal foil in the present invention are not particularly limited. Therefore, the carrier base material surface refers to the exposed surface of the carrier base material. Moreover, what is necessary is just to equip at least one surface of the carrier base material surface 4 with an uneven | corrugated shape. As an aspect provided with uneven | corrugated shape in the carrier base material surface 4, the protrusion part 7 may be provided in the single side | surface of the carrier base material 2, or may be provided in both surfaces. It should be noted that the protrusion 7 is a part of the carrier substrate 2.

  In the process B, as described above, since the protruding portion (copper plating layer) 7 is embedded and plated at a lower height than the protruding resist pattern 6, the protruding resist pattern 6 is immersed in an aqueous sodium hydroxide solution. The area can be increased, and the aqueous sodium hydroxide solution easily accumulates in the concave portion surrounded by the protruding portion 7 and the protruding resist pattern 6 protruding higher than the protruding portion 7. As a result, the contact between the protruding resist pattern 6 and the aqueous sodium hydroxide solution increases, the swelling of the resist component can be promoted, and the swelling of the resist component at the interface between the protruding portion 7 and the protruding resist pattern 6 is promoted. Thus, the protruding resist pattern 6 can be quickly removed. Therefore, it is preferable that the buried plating is not plated to a height that completely fills the resist recess 3.

  The uneven shape on the surface of the carrier substrate thus formed will be described in more detail. The uneven shape of the carrier substrate surface 4 has the same uneven shape as the uneven shape desired to be formed on the composite metal foil. The protrusion height of the protrusion 7 is preferably 10 μm to 50 μm. When the protrusion height of the protrusion 7 is less than 10 μm, there is no merit as a composite metal foil having an uneven shape. On the other hand, if the protruding height of the protruding portion 7 exceeds 50 μm, the manufacturing cost due to increasing the protruding portion 7 increases, which is not preferable from the viewpoint of industrial productivity. Moreover, there is no merit which uses the manufacturing method which concerns on this invention suitable for microfabrication.

  Further, as shown in FIG. 1 (4), the side wall surface 8 of the protruding portion 7 is exposed in the cross-sectional shape as the side wall surface 8 and the bottom surface of the carrier concave portion 11 formed between the protruding portions 7. It is preferable that the angle θ formed with the carrier substrate surface 4 has an inclination in a range of 90 ° to 135 °. If the side wall surface 8 is inclined with an angle θ of less than 90 °, it is difficult to continuously cover the entire surface of the carrier recess 11 by physical vapor deposition when the covering metal layer 9 is formed. More preferably, the angle θ is in the range of 95 ° to 135 °. And since the present invention is a composite metal foil characterized by microfabrication, considering the shape such as the width and height of the uneven shape, an uneven shape that is industrially practical can be obtained at an angle θ exceeding 135 °. I think that it cannot be formed.

  Moreover, as for the uneven | corrugated shape of the carrier base material surface 4, the pitch of the carrier recessed part 11 and the projection part 7 in the cross-sectional observation shall be 30 micrometers-200 micrometers. Here, the pitch of the carrier recess 11 and the protrusion 7 indicates the distance between the adjacent protrusions 7 when the carrier substrate surface 4 is provided with a plurality of protrusions 7. For example, FIG. As shown in 5), the distance L from the projection start point of one projection 7 to the projection start point of the next projection 7 is shown. In consideration of the shape such as the protrusion height of the protrusion 7 and the inclination of the side wall surface 8 of the present invention and the manufacturing method suitable for fine shape processing, the pitch of 30 μm to 200 μm is considered to be a range where the advantages of the present invention can be utilized.

  The carrier substrate surface 4 (including the protrusions 7) after the protrusion-like resist pattern 6 is removed can be further processed into a concavo-convex shape by plating, etching, or the like according to the purpose.

  By adopting the above method, it is possible to cope with the miniaturization of the uneven shape formed on the carrier substrate surface 4. Further, the projection 7 formed by embedding the resist recess 3 by using an electroplating method has a smooth surface, and the coated metal layer formed on the upper surface of the projection 7 and the carrier substrate surface 4 9 can be made to have a smooth surface shape, and the uneven shape can be finished beautifully.

Step C: The coated metal layer 9 is formed on the surface of the carrier base material on which the concavo-convex shape has been formed by using a vapor phase growth method to obtain a composite metal foil having the concavo-convex shape.

  In addition, the vapor phase growth method said here includes all the things called PVD method and CVD method. The CVD method includes chemical vapor deposition, gas source MBE, ALCVD, and plasma CVD. Moreover, as a PVD method, the vacuum evaporation method, the sputtering evaporation method provided with various ion guns, the ion plating method, etc. are contained. In particular, the sputtering deposition method or the electron beam deposition method can form a film of titanium or the like extremely densely and uniformly, and can form a smooth deposition surface with high adhesion to the carrier substrate. Therefore, it is suitable for thinning a high melting point metal such as titanium, tantalum, or niobium, an alloy, a compound, etc., and it is preferable because a high-quality composite metal foil can be provided. Further, since the sputtering vapor deposition method does not use a solvent or the like unlike the wet surface treatment, a solvent treatment or an air pollution prevention treatment by a reactant is unnecessary.

  The covering metal layer 9 has a thickness of 1 μm to 15 μm. When the thickness of the covering metal layer 9 is less than 1 μm, the practical mechanical strength and covering accuracy are insufficient. On the other hand, it is possible to manufacture a product having a thickness of more than 15 μm, but the cost is increased from an industrial viewpoint and the dimensional accuracy is lowered.

  Here, the composite metal foil according to the present invention is manufactured by depositing a film on the surface of the concavo-convex shape formed on the carrier substrate surface 4 by a vapor phase growth method. It is characterized by a high point. In addition, the upper limit of the protrusion height of the protrusion part 7 is prescribed | regulated by the thickness which can set a resist layer. And the uneven | corrugated shape formed in the carrier base material surface 4 is prescribed | regulated to the shape of the protruding resist pattern 6. FIG. In addition, since the resist recess 3 needs to expose at least the carrier substrate surface 4 necessary for the embedded plating, the bottom surface of the resist recess 3 is the carrier substrate surface 4.

<Composite metal foil>
The composite metal foil according to the present invention is, for example, as shown in FIG. 1, a metal foil provided with a coated metal layer 9 along the concavo-convex shape provided on the carrier substrate surface 4, and the method for producing the composite metal foil described above. It is obtained by using.

  The covering metal layer 9 has a thickness of 1 μm to 15 μm and is preferably a metal made of titanium or the like. When the corrosion resistance is required, such as when the composite metal foil or molded metal foil according to the present invention is used for a fuel cell separator, the total composition ratio of titanium, tantalum and niobium should be 70% or more of the total. Is preferred. And as for the uneven | corrugated shape of the composite metal foil 1, the pitch of the carrier recessed part 11 and the projection part 7 in the cross-sectional observation is 30 micrometers-200 micrometers.

  Moreover, the maximum thickness in cross-sectional observation is 38 micrometers-400 micrometers. For example, in the cross-sectional view of the composite metal foil shown in FIG. 2 (5), the maximum thickness in the cross-sectional observation is the thickness T between the maximum protrusions of the protrusions on both sides. The maximum thickness is considered to be preferably 38 μm or more in consideration of the shape of the carrier substrate 2 and the protrusion 7 and the stable strength. On the other hand, when it exceeds 400 μm, there is no merit of using the manufacturing method according to the present invention in terms of manufacturing cost.

  Further, the material of the carrier substrate is not particularly limited as long as it has conductivity as described in the method for producing the composite metal foil. The shape of the carrier substrate is selected according to the use of the composite metal foil, and there is no particular limitation. However, from the viewpoint of mechanical strength and handling properties, the thickness is 18 μm or more. Seems desirable.

  Here, as shown in FIG. 1, the method for producing a composite metal foil according to the present invention is characterized in that a coated metal layer 9 is formed on a carrier substrate surface 4 having an uneven shape by a vapor phase growth method. . Therefore, the composite metal foil 1 of the present invention is provided with an uneven shape on one surface of the composite metal foil 1 and provided with the coated metal layer 9, provided with an uneven shape on one side, and the coated metal layer 9 on both sides thereof. As shown in FIG. 2, those provided are provided with a concavo-convex shape on both sides and a coating metal layer 9 on both sides.

  In addition, although FIG. 2 showed the example in which the uneven | corrugated state of both surfaces was symmetrical in order to make it easy to understand the state which has uneven | corrugated shape on both surfaces, it is not limited to this. The production method of the present invention is characterized in that the degree of freedom in designing the concavo-convex shape of each surface of the composite metal foil is high, and therefore can be manufactured even if the concavo-convex shape of each surface is different. For example, the direction of the groove formed by the carrier concave portion on one surface of the composite metal foil and the direction of the groove formed by the carrier concave portion on the other surface are formed to be twisted with respect to each other. There may be.

<Method for producing molded metal foil>
As described above, the molded metal foil 10 according to the present invention has a concavo-convex shape including only the coated metal layer 9 obtained by removing the carrier base material 2 from the composite metal foil 1. That is, after passing through the steps A to C described in the method for producing the composite metal foil, the coated metal layer 9 is removed by removing the carrier base material 2 from the composite metal foil 1, for example, as shown in FIG. It can be obtained by separating and collecting only. Therefore, description of the said process A-the process C contained in the manufacturing method of shaping | molding metal foil is omitted, and it demonstrates from the process of isolate | separating the said carrier base material 2 from the composite metal foil 1 with reference to the example shown in FIG. To do.

  For example, as shown in FIG. 3 (5), the method for producing a molded metal foil according to the present invention first applies the coated metal layer 9 on the surface of the carrier substrate 2 having a concavo-convex shape on one side by the steps A to C. The formed composite metal foil 1 is produced. Thereafter, the carrier substrate 2 is removed as shown in FIG. Specifically, the composite metal foil 1 including the uneven coated metal layer 9 on one side of the carrier substrate 2 is immersed in a solution capable of selective etching of the constituent metal of the coated metal layer 9 and the constituent metal of the carrier substrate 2. Then, only the metal component of the carrier substrate is removed by etching to form a molded metal foil. In addition, since the projection part 7 is a part of the carrier base material 2 as mentioned above, all the carrier base materials including the projection part 7 are removed. As the etching solution, a copper etching solution such as copper salt or iron salt added with hydrochloric acid or hydrogen peroxide is used as a solution capable of dissolving the carrier substrate 2 without dissolving the coated metal layer 9.

  Here, it is difficult to manufacture the molded metal foil 10 having only a portion of the coated metal layer 9 having a thickness of about 10 μm and covering along the uneven shape without a carrier substrate. Therefore, in the molded metal foil 10, it is clearly stated that the carrier base material 2 (including the protrusions 7) is a member necessary for the molded metal foil manufacturing process and does not constitute the manufactured molded metal foil 10. Keep it.

  In order to dissolve the carrier base material 2 so as to be removed by etching while leaving the coated metal layer 9, the metal component that can be selected as the carrier base material is determined by the metal component of the coated metal layer 9 and the kind of the etching solution. Therefore, a metal component that is soluble in an etching solution that does not dissolve a metal composed of titanium or the like may be used as a carrier substrate. Many metals soluble in an etchant that does not dissolve metals composed of titanium, etc. are conceivable. As long as the desired plating can be performed, the bath composition, plating conditions, etc. can be arbitrarily changed, and no particular limitation is required. . For example, a metal plating layer made of copper, nickel, or an alloy thereof is preferable in terms of economy. Moreover, the thickness of the metal plating layer can be adjusted by the electrodeposition time of electrolytic plating. Further, it is preferable to use a metal material for the carrier base material because it is easy to reuse and highly convenient.

  The coated metal layer 9 may have a structure of two or more layers made of different metals other than the single layer structure made of a metal layer made of titanium or the like.

<Molded metal foil>
The molded metal foil 10 is preferably composed of a metal component composed of titanium or the like. Further, the molded metal foil 10 is formed of a single layer made of metal made of titanium or the like, or a metal layer made of titanium or the like is first formed on the carrier base surface 4 made of copper, and then copper, nickel, etc. An example of a three-layered coated metal layer in which a metal layer made of a metal layer and a metal layer made of a titanium foil are further considered. Here, although the thickness of the covering metal layer 9 of the composite metal foil 1 is 1 μm to 15 μm, the metal foil having a concavo-convex shape is insufficient in strength alone when the thickness is less than 7 μm. Is required. In such a case, in the latter case, when forming a molded metal foil composed of a plurality of coated metal layers, an extremely thin metal layer composed of titanium can be supported by a metal layer composed of copper, nickel, etc. The physical strength of titanium foil, which is difficult to handle, can be reinforced. In addition, since the shaping | molding metal foil 10 which concerns on this invention removes the carrier base material 2 from the composite metal foil 1 by an etching, the metal which comprises the surface of the shaping | molding metal foil 10 which consists of multiple layers is a constituent metal of a carrier base material. In addition, it is necessary to set in consideration of a solution for etching the carrier substrate. If the surface of the molded metal foil 10 is made of a metal composed entirely of titanium or the like, the solution to be etched can be easily selected.

  Moreover, it is preferable that the shaping | molding metal foil 10 is 10 micrometers-50 micrometers in thickness. Here, when the thickness is less than 10 μm, it is difficult to maintain the shape of the molded metal foil. On the other hand, in the case where the thickness of the molded metal foil exceeds 50 μm, the merit of the molded metal foil of the present invention formed in a fine concavo-convex shape using the vapor phase growth method is not exhibited.

  Since the formed metal foil according to the present invention is formed by a vapor phase growth method, a dense, uniform and smooth film formation surface can be formed, and a fine and beautiful uneven shape is provided. Further, a metal foil formed of a metal whose surface is easily oxidized, such as titanium, has good corrosion resistance. In addition, since the carrier base material 2 is dissolved and removed using an etching solution, unnecessary force does not act and the molded metal foil is less likely to be damaged and beautiful compared to the case of peeling by physical means. Finishing can be done easily. In this way, high-quality molded metal foil can be manufactured with a reduced number of manufacturing steps compared to conventional pressing methods, and it is possible to reduce the chance of manufacturing loss, thereby improving productivity. .

  Hereinafter, the present invention will be specifically described with reference to examples. In addition, this invention is not restrict | limited to a following example.

  In Example 1, an example in which the titanium layer is the coated metal layer 9 is shown. However, the present invention is not limited to this. For example, a metal layer made of a different metal is vapor-phased on the surface of the carrier substrate. After forming the film by the growth method, the coated metal layer 9 may be a metal layer composed of a plurality of layers, such as forming the above-described titanium layer.

  FIG. 2 is a schematic diagram for explaining a manufacturing process of the composite metal foil in the first embodiment. In Example 1, as shown in FIG. 2 (5), a carrier base material made of copper having a concavo-convex shape on both sides and a surface of the carrier base material is titanium by the method for manufacturing a composite metal foil according to the present invention. The example which manufactures the composite metal foil covered with the film | membrane which uses as a main material is shown.

Step A: A protruding resist pattern 6 is formed on the carrier substrate surface 4. Using a rolled copper foil having a thickness of 35 μm as the carrier substrate 2, a protruding resist pattern 6 was formed on the carrier substrate surface 4 using photolithography. First, after removing the rolling oil of the surface of the rolled copper foil which is the carrier base material 2 by a degreasing process, the glossy surface was washed with dilute sulfuric acid, and then washed with water and dried. Next, as shown in FIG. 2 (1), a 25 μm-thick dry film as the resist layer 5 was placed on the glossy surface of the dried copper foil and attached by a laminator.

  Next, the resist layer 5 was formed into a protruding resist pattern 6 for forming a concavo-convex shape to be formed on the carrier substrate surface 4. That is, a continuous pattern photomask having the same surface shape as the uneven surface to be formed on the carrier substrate is placed in close contact with or close to the surface of the resist layer 5, and the dry film is irradiated with ultraviolet rays. Developed by exposure. Next, an unexposed portion of the photomask pattern was removed by peeling with a 1% sodium carbonate solution, thereby forming a desired protruding resist pattern 6 as shown in FIG. The protruding resist pattern 6 was formed in a protruding shape having a substantially trapezoidal cross section on the carrier substrate surface 4 at a position corresponding to the convex portion formed on the composite metal foil 1.

Step B: Next, embedded plating was performed on the resist recesses 3 formed by the carrier base material surface 4 and the protruding resist pattern 6 using an electrolytic plating method. The metal plating layer is made of copper, and the bath composition is set as a plating condition with a CuSO ₄ · 5H ₂ O concentration of 250 g / l and a H ₂ SO ₄ concentration of 90 g / l, a current density of 5 A / dm ² and a bath temperature of 50 ° C. A copper plating layer having a thickness of 13 μm was electrodeposited. At this stage, since the thickness of the protruding resist pattern 6 is 25 μm and the thickness of the copper plating layer is 13 μm, the copper plating layer is recessed below the protruding resist pattern 6.

  Subsequently, the protruding resist pattern 6 was immersed in a 3% aqueous sodium hydroxide solution heated to 50 ° C. to swell and remove the resist component. Thus, by removing the protruding resist pattern 6, the protruding portion 7 was formed on the carrier substrate surface 4, and the uneven protruding portion 7 was formed on the carrier substrate surface 4.

  The protrusion 7 is substantially trapezoidal in the cross section of the protrusion 7, the protrusion height from the carrier substrate surface 4 is 13 μm, the upper side (upper surface of the protrusion) is 48 μm, and the side wall surface 8 is The angle θ formed between the carrier substrate surface 4 and the side wall surface 8 exposed between the protrusions has an inclination of 100 °. And several protrusion part was formed in the carrier base-material surface with the pitch of 100 micrometers. Thus, a carrier base material having an uneven shape corresponding to the uneven shape of the composite metal foil 1 to be produced was obtained.

Step C: A metal foil was formed on the carrier substrate surface 4 on which the concavo-convex shape was formed by a sputtering vapor deposition method to form a coated metal layer 9. That is, an inert gas is converted into plasma on a target made of a titanium material and sputtered at an accelerating voltage on the carrier base material surface 4 to form a film along the uneven shape of the carrier base material surface 4. A 2 μm titanium layer (coating metal layer 9) was formed.

  By performing the steps so far on both sides of the carrier substrate, composite metal foil 1 having uneven shapes on both sides was obtained as shown in FIG. That is, a plurality of protrusions 7 having a protrusion height of 13 μm are formed on both surfaces of a carrier substrate 2 made of copper having a thickness of 35 μm at a pitch of 100 μm, and titanium present on the surface of the protrusion 7 is mainly used. The thickness of the covering metal layer 9 used as a material was 2 μm. Therefore, a composite metal foil having the covering metal layer 9 along the uneven shape formed on both surfaces and having a maximum thickness of 65 μm was obtained.

  The composite metal foil manufactured according to Example 1 has a fine and beautiful uneven shape. And since titanium is formed into a film by sputtering vapor deposition method, as above-mentioned, a precise | minute and uniform and smooth film-forming surface can be formed. Furthermore, since the titanium layer is formed so as to cover the surface of copper as the carrier base material, the composite metal foil having a small and lightweight, excellent corrosion resistance, and having different uneven shapes on each surface, For example, it is suitable as a separator for a fuel cell. That is, in the case of a fuel cell, if corrosion occurs at a portion where the separator material and the electrolyte are in contact with each other, the electrolyte is lost and the internal resistance is increased. However, since titanium has good heat resistance and corrosion resistance, It is suitable for this. Furthermore, it can contribute to size reduction and weight reduction of the separator, and contributes to improvement of the performance of the fuel cell.

  In Example 2, by using the method for producing a molded metal foil according to the present invention, a plurality of substantially trapezoidal convex portions having a cross-sectional shape of 15 μm in height are continuously formed using titanium as a main material, and the forming has a thickness of 13 μm. The example which manufactures metal foil is shown. That is, in Example 1, although it was set as the composite metal foil containing a carrier base material, the metal foil of Example 2 differs from Example 1 by the point which removes a carrier base material after composite metal foil preparation.

  First, as in the example shown in FIG. 1, a composite metal foil 1 having a coated metal layer 9 on one side of a carrier substrate 2 is manufactured, and then, as shown in FIG. Was immersed in a copper etching solution made of salt copper to which hydrogen peroxide was added, and only the carrier substrate 2 was removed by etching to obtain a molded metal foil 10.

  The molded metal foil 10 obtained by the above method is made of titanium as a main material, has a thickness of 30 μm, and a plurality of concave and convex shapes of the same shape are formed at a pitch of 100 μm.

  The molded metal foil produced according to Example 2 has a fine and beautiful uneven shape. Titanium has a characteristic that its surface is easily oxidized, and a metal foil formed by sputtering vapor deposition becomes a titanium foil having good corrosion resistance. In this way, a high-quality molded metal foil can be manufactured with a reduced number of manufacturing steps. And compared with the conventional press method, the shaping | molding metal foil with a fine and high degree of freedom of uneven | corrugated shape can be obtained.

  The method for producing a composite metal foil and a molded metal foil according to the present invention is suitable for fine processing with few restrictions on the uneven shape, and therefore, it is possible to manufacture a composite metal foil having an uneven shape corresponding to a wide range of needs. Furthermore, since the number of manufacturing steps is significantly less than that of the conventional pressing method, a high-quality composite metal foil can be manufactured efficiently. It is also suitable for the production of metal foils that have been processed with uneven shapes on metals that have been difficult to manufacture, such as titanium, tantalum, niobium, etc., so it is made of a metal that has excellent corrosion resistance, heat resistance, and oxidation resistance. It is possible to manufacture a high-quality composite metal foil that is uniformly formed, and the range of selection of the material for the metal foil having a concavo-convex shape is widened. Therefore, for example, a separator for a fuel cell, a support for a catalyst for promoting a chemical reaction, a liquid reforming filter for imparting metal ions to a liquid to reform a liquid such as drinking water, an electromagnetic wave shield, and a magnetic material In a wide range of fields such as conductive materials, small heat sinks, etc., it is possible to achieve high efficiency by downsizing, weight reduction, or high density.

It is a schematic diagram for demonstrating the process which concerns on the manufacturing method of the composite metal foil which concerns on this invention, and a shaping | molding metal foil. It is a schematic diagram for demonstrating the process which concerns on the manufacturing method of the composite metal foil in Example 1. FIG. It is a schematic diagram for demonstrating the process which concerns on the manufacturing method of the shaping | molding metal foil in Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Composite metal foil 2 ... Carrier base material 3 ... Resist recessed part 4 ... Carrier base material surface 6 ... Projection-like resist pattern 7 ... Projection part 8 ... Side wall surface 9 ... Coated metal layer 10 ... Molded metal foil 11 ... Carrier recess

Claims (16)

It is a manufacturing method of composite metal foil provided with an uneven surface, Comprising: The manufacturing method of composite metal foil characterized by including the following processes A-process C.
Step A: A step of forming, on the surface of the carrier substrate, a protruding resist pattern that becomes a mold for forming the same uneven shape on the surface of the carrier substrate as the uneven shape provided for the composite metal foil.
Step B: After embedding plating using an electrolytic plating method in a resist recess formed by the surface of the carrier substrate and the protruding resist pattern, the protruding resist pattern is removed and the surface of the carrier substrate The process which makes a carrier base material provided with an uneven | corrugated shape on the surface by forming a projection part in this.
Step C: A step of forming a coated metal layer on the surface of the carrier base material on which the concavo-convex shape is formed by using a vapor phase growth method to obtain a composite metal foil having the concavo-convex shape. 2. The production of a composite metal foil according to claim 1, wherein in the step A, a resist layer is formed on a surface of a carrier substrate, and the protruding resist pattern is formed on the surface of the carrier substrate by a photomask method. Method. The method for producing a composite metal foil according to claim 1, wherein the vapor phase growth method is either a sputtering vapor deposition method or an electron beam vapor deposition method. In the carrier base material having the concavo-convex shape, the side wall surface in the cross section of the protrusion formed on the surface of the carrier base material has an angle formed by the side wall surface and the surface of the carrier base material exposed between the protrusions of 90 °. The method for producing a composite metal foil according to any one of claims 1 to 3, which has an inclination in a range of ~ 135 °. The method for producing a composite metal foil according to any one of claims 1 to 4, wherein a protrusion height of the protrusion formed on the surface of the carrier substrate is 10 to 50 µm. It is a composite metal foil provided with a coating metal layer along the uneven shape provided on the surface of the carrier substrate,
A composite metal foil obtained by using the method for producing a composite metal foil according to any one of claims 1 to 5. The composite metal foil according to claim 6, wherein the covering metal layer is composed of titanium, tantalum, niobium, or an alloy thereof. The composite metal foil according to claim 5 or 6, wherein the covering metal layer has a thickness of 1 µm to 15 µm. 9. The composite metal foil having an uneven shape according to claim 6, wherein the maximum thickness in cross-sectional observation is 38 μm to 400 μm. The composite metal foil according to any one of claims 6 to 9, wherein the concavo-convex shape has a carrier concave portion and a protruding portion pitch in a cross-sectional observation of 30 µm to 200 µm. The composite metal foil according to any one of claims 6 to 10, wherein the protrusions provided on the surface of the carrier substrate are formed on both surfaces of the carrier substrate. Among the composite metal foils according to any one of claims 6 to 10, a metal foil obtained by using a composite metal foil comprising an uneven-shaped coated metal layer on one side of a carrier substrate,
A molded metal foil obtained by separating and collecting only the coated metal layer by removing the carrier substrate of the metal foil. The molded metal foil according to claim 12, which has a thickness of 10 µm to 50 µm. The molded metal foil according to claim 12 or 13, which is composed of a metal component of titanium, tantalum, niobium, or an alloy thereof. The molded metal foil according to claim 12 or 13, which has a structure of two or more layers comprising one made of titanium, tantalum, niobium or an alloy thereof and a different kind of metal. A method for producing a molded metal foil according to any one of claims 12 to 15,
A composite metal foil having an uneven-shaped coated metal layer on one side of a carrier base material is immersed in a solution that can be selectively etched between the constituent metal of the coated metal layer and the constituent metal of the carrier base material, and only the metal component of the carrier base material is immersed. A method for producing a molded metal foil, characterized by etching away.

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