Method for depositing film, film deposition device, and method for manufacturing electrode foil

Abstract

To provide means for efficiently forming a dielectric layer at both principal surfaces of a metal foil.SOLUTION: A method for depositing a layer including a metal oxide includes: a heating step of bringing part of a metal foil including a first metal into contact with one or more heat generators to heat the metal foil; a first contact step of bringing a first gas including a second metal into contact with both surfaces of the metal foil while part of the metal foil is supported; and a second contact step of bringing a second gas including an oxidant into contact with both surfaces of the metal foil while the part of the metal foil is supported.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a film forming method, a film forming apparatus, and a method for manufacturing an electrode foil using atomic layer deposition, and to a method and apparatus for forming a layer containing a metal oxide (dielectric layer) on both sides of a metal foil. [Background technology]

[0002] A metal oxide (dielectric) layer is formed on the surface of a metal foil used as an electrode foil for an electrolytic capacitor. Patent Document 1 teaches that a dielectric layer is formed on the main surface of the metal foil by atomic layer deposition (ALD). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2017-154461 Summary of the Invention [Problem to be solved by the invention]

[0004] The dielectric layer is usually formed on both main surfaces of the metal foil. From the viewpoint of productivity, it is required to efficiently form the dielectric layer on both main surfaces of the metal foil. [Means for solving the problem]

[0005] A first aspect of the present invention relates to a method for forming a layer containing a metal oxide, comprising: a heating step of heating a portion of a metal foil containing a first metal by contacting the metal foil with one or more heating elements; a first contacting step of contacting both sides of the metal foil with a first gas containing a second metal while the portion of the metal foil is supported; and a second contacting step of contacting both sides of the metal foil with a second gas containing an oxidizer while the portion of the metal foil is supported.

[0006] A second aspect of the present invention relates to a film forming apparatus comprising at least one chamber, a pressure control unit that controls the pressure in the chamber to a reduced pressure atmosphere, a first supply port that supplies a first gas containing a second metal to the chamber, a second supply port that supplies a second gas containing an oxidizer to the chamber, a first exhaust port that discharges the first gas from the chamber, a second exhaust port that discharges the second gas from the chamber, and one or more heating elements that are disposed in the chamber and contact a portion of a metal foil that is an object to be formed into a film to heat the metal foil, wherein the first gas and the second gas are supplied so as to contact both main surfaces of the metal foil.

[0007] A third aspect of the present invention relates to a method for producing an electrode foil, the method comprising: a preparation step of preparing a metal foil containing a first metal; a roughening step of roughening both main surfaces of the metal foil; a heating step of bringing a portion of the roughened metal foil into contact with one or more heating elements to heat the metal foil; a first contact step of contacting both sides of the metal foil with a first gas containing a second metal while the portion of the metal foil is supported; and a second contact step of contacting both sides of the metal foil with a second gas containing an oxidizer while the portion of the metal foil is supported to form a dielectric layer.

[0008] A fourth aspect of the present invention relates to a method for forming a layer containing a metal oxide, comprising: a first contacting step of contacting both sides of a metal foil containing a first metal with a first gas containing a second metal; a second contacting step of contacting both sides of the metal foil with a second gas containing an oxidizer; and a first application step of contacting a portion of the metal foil with one or more first current collectors and applying a voltage to the metal foil in the presence of the first gas.

[0009] A fifth aspect of the present invention relates to a method for producing an electrode foil, comprising: a preparation step of preparing a metal foil containing a first metal; a roughening step of roughening both main surfaces of the metal foil; a first contact step of contacting both surfaces of the roughened metal foil with a first gas containing a second metal; a second contact step of contacting both surfaces of the metal foil with a second gas containing an oxidizer; and a first application step of contacting a portion of the metal foil with one or more first current collectors and applying a voltage to the metal foil in the presence of the first gas.

[0010] A sixth aspect of the present invention relates to a method for forming a layer containing a metal oxide, comprising: a first contacting step of contacting both sides of a metal foil containing a first metal with a first gas containing a second metal; a second contacting step of contacting both sides of the metal foil with a second gas containing an oxidizer; and an application step of contacting a part of the metal foil with one or more current collectors and applying a voltage to the metal foil in the presence of the second gas.

[0011] A seventh aspect of the present invention relates to a method for producing an electrode foil, comprising: a preparation step of preparing a metal foil containing a first metal; a roughening step of roughening both main surfaces of the metal foil; a first contact step of contacting both surfaces of the roughened metal foil with a first gas containing a second metal; a second contact step of contacting both surfaces of the metal foil with a second gas containing an oxidizer; and a second application step of contacting a portion of the metal foil with one or more second current collectors and applying a voltage to the metal foil in the presence of the second gas.

[0012] An eighth aspect of the present invention relates to a film forming apparatus comprising at least one chamber, a pressure control unit that controls the pressure in the chamber to a reduced pressure atmosphere, a first supply port that supplies a first gas containing a second metal to the chamber, a second supply port that supplies a second gas containing an oxidant to the chamber, a first exhaust port that discharges the first gas from the chamber, a second exhaust port that discharges the second gas from the chamber, one or more current supply bodies in contact with a portion of a metal foil that is an object to be formed on a film, and a counter electrode that generates a voltage difference between the metal foil and the current supply body, wherein the first gas and the second gas are supplied so as to contact both main surfaces of the metal foil.

[0013] A ninth aspect of the present invention relates to a method for forming a layer containing a metal oxide, comprising: a heating step of bringing a portion of a metal foil containing a first metal into contact with one or more heating elements to heat the metal foil; a first contacting step of bringing a first gas containing a second metal into contact with both sides of the metal foil while the portion of the metal foil is supported; a second contacting step of bringing a second gas containing an oxidizer into contact with both sides of the metal foil while the portion of the metal foil is supported; and an application step of bringing a portion of the metal foil into contact with one or more current feeders and applying a voltage to the metal foil in the presence of at least one of the first gas and the second gas. Effect of the Invention

[0014] According to the present invention, a dielectric layer can be efficiently formed on both main surfaces of a metal foil by using atomic layer deposition. [Brief description of the drawings]

[0015] [Figure 1] 1 is a flowchart showing a film forming method according to a first embodiment of the present invention. [Diagram 2] 1 is a flowchart showing a method for producing an electrode foil according to a first embodiment of the present invention. [Diagram 3] 1 is an SEM image (300x) of a cross section of a roughened metal foil according to one embodiment of the present invention. [Figure 4] FIG. 1 is a side view conceptually showing an example of a film forming apparatus according to a first embodiment of the present invention. [Diagram 5] FIG. 4 is a side view conceptually showing another example of the film forming apparatus according to the first embodiment of the present invention. [Figure 6] FIG. 4 is a side view conceptually showing another example of the film forming apparatus according to the first embodiment of the present invention. [Figure 7] FIG. 2 is a side view conceptually showing a main part of another film forming apparatus according to the first embodiment of the present invention. [Figure 8] FIG. 4 is a side view conceptually showing another example of the film forming apparatus according to the first embodiment of the present invention. [Figure 9] FIG. 4 is a side view conceptually showing another example of the film forming apparatus according to the first embodiment of the present invention. [Figure 10]5 is a flowchart showing a film forming method according to a second embodiment of the present invention. [Figure 11] 5 is a flowchart showing a method for producing an electrode foil according to a second embodiment of the present invention. [Figure 12] 5 is a flowchart showing a film forming method according to a third embodiment of the present invention. [Figure 13] 5 is a flowchart showing a method for producing an electrode foil according to a third embodiment of the present invention. [Figure 14] 4 is a flowchart showing a film forming method according to second and third aspects of the present invention. [Figure 15] 5 is a flowchart showing a method for producing an electrode foil according to the second and third embodiments of the present invention. [Figure 16] FIG. 2 is a side view conceptually showing an example of a film forming apparatus according to the second and third aspects of the present invention. [Figure 17] FIG. 4 is a side view conceptually showing an example of another film forming apparatus according to the second and third aspects of the present invention. [Figure 18] FIG. 11 is a side view conceptually showing an example of still another film forming apparatus according to the second and third aspects of the present invention. [Figure 19] FIG. 11 is a side view conceptually showing an example of still another film forming apparatus according to the second and third aspects of the present invention. [Figure 20] FIG. 11 is a side view conceptually showing an example of still another film forming apparatus according to the second and third aspects of the present invention. [Figure 21] FIG. 11 is a side view conceptually showing an example of still another film forming apparatus according to the second and third aspects of the present invention. [Figure 22] 5 is a flowchart showing a film forming method according to a fourth embodiment of the present invention. [Diagram 23] 10 is a flowchart showing a method for producing an electrode foil according to a fourth embodiment of the present invention. [Figure 24] FIG. 11 is a side view conceptually showing an example of a film forming apparatus according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] In this embodiment, the object on which the dielectric layer is formed is a metal foil. The metal foil has high heat resistance, thermal conductivity, and electrical conductivity compared to resin films and the like, and also has a certain degree of rigidity. In this embodiment, by utilizing such properties of the metal foil, a layer containing a metal oxide (dielectric layer) is formed simultaneously on both main surfaces of the metal foil.

[0017] The film forming method according to the first embodiment includes a heating step of contacting a portion of a metal foil containing a first metal with one or more heating elements to heat the metal foil, a first contact step of contacting both sides of the metal foil with a first gas containing a second metal while the portion of the metal foil is supported, and a second contact step of contacting both sides of the metal foil with a second gas containing an oxidizer while the portion of the metal foil is supported.

[0018] The film forming method according to the first aspect is carried out using a film forming apparatus as described below. The present embodiment encompasses this film forming apparatus. That is, the film forming apparatus according to the first embodiment includes at least one chamber, a pressure control unit that controls the pressure in the chamber to a reduced pressure atmosphere, a first supply port that supplies a first gas containing a second metal to the chamber, a second supply port that supplies a second gas containing an oxidizing agent to the chamber, a first exhaust port that exhausts the first gas from the chamber, a second exhaust port that exhausts the second gas from the chamber, and one or more heating elements that are disposed in the chamber and contact a part of the metal foil that is the film forming target to heat the metal foil. The first gas and the second gas are supplied so as to contact both main surfaces of the metal foil.

[0019] An electrode foil for an electrolytic capacitor can be manufactured by using the film-forming apparatus and / or the film-forming method according to the first aspect. The present embodiment includes a method for manufacturing this electrode foil. That is, the manufacturing method of the electrode foil according to the first embodiment includes a preparation step of preparing a metal foil containing a first metal, a roughening step of roughening both main surfaces of the metal foil, a heating step of contacting a portion of the roughened metal foil with one or more heating elements to heat the metal foil, a first contact step of contacting both sides of the metal foil with a first gas containing a second metal while the portion of the metal foil is supported, and a second contact step of contacting both sides of the metal foil with a second gas containing an oxidizer while the portion of the metal foil is supported to form a dielectric layer.

[0020] The film forming method according to the second embodiment includes a first contacting step of contacting both sides of a metal foil containing a first metal with a first gas containing a second metal, a second contacting step of contacting both sides of the metal foil with a second gas containing an oxidizer, and a first application step of contacting a portion of the metal foil with one or more first current collectors and applying a voltage to the metal foil in the presence of the first gas.

[0021] The film-forming method according to the second aspect can be used to manufacture an electrode foil for an electrolytic capacitor. This embodiment encompasses the method for manufacturing this electrode foil. That is, the manufacturing method of the electrode foil according to the second embodiment includes a preparation step of preparing a metal foil containing a first metal, a roughening step of roughening both main surfaces of the metal foil, a first contact step of contacting both sides of the roughened metal foil with a first gas containing a second metal, a second contact step of contacting both sides of the metal foil with a second gas containing an oxidizer, and a first application step of contacting a portion of the metal foil with one or more first current collectors and applying a voltage to the metal foil in the presence of the first gas.

[0022] The film forming method according to the third aspect includes a first contacting step of contacting both sides of a metal foil containing a first metal with a first gas containing a second metal, a second contacting step of contacting both sides of the metal foil with a second gas containing an oxidizer, and an application step of contacting a portion of the metal foil with one or more power suppliers and applying a voltage to the metal foil in the presence of the second gas.

[0023] The film-forming method according to the third aspect can be used to manufacture an electrode foil for an electrolytic capacitor. This embodiment encompasses the method for manufacturing this electrode foil. That is, the manufacturing method of the electrode foil according to the third embodiment includes a preparation step of preparing a metal foil containing a first metal, a roughening step of roughening both main surfaces of the metal foil, a first contact step of contacting both sides of the roughened metal foil with a first gas containing a second metal, a second contact step of contacting both sides of the metal foil with a second gas containing an oxidizer, and a second application step of contacting a portion of the metal foil with one or more second current collectors and applying a voltage to the metal foil in the presence of the second gas.

[0024] The film forming methods according to the second and third aspects are carried out using a film forming apparatus as described below. This embodiment encompasses this film forming apparatus. That is, the film forming apparatus according to the second and third aspects includes at least one chamber, a pressure control unit for controlling the pressure in the chamber to a reduced pressure atmosphere, a first supply port for supplying a first gas containing a second metal to the chamber, a second supply port for supplying a second gas containing an oxidizing agent to the chamber, a first exhaust port for discharging the first gas from the chamber, a second exhaust port for discharging the second gas from the chamber, one or more power feeders that contact a part of the metal foil that is the film forming target, and a counter electrode that generates a voltage difference between the metal foil and the power feeder. The first gas and the second gas are supplied so as to contact both main surfaces of the metal foil.

[0025] The film forming method according to the fourth aspect includes a heating step of contacting a portion of a metal foil containing a first metal with one or more heating elements to heat the metal foil, a first contact step of contacting both sides of the metal foil with a first gas containing a second metal while the portion of the metal foil is supported, a second contact step of contacting both sides of the metal foil with a second gas containing an oxidizer while the portion of the metal foil is supported, and an application step of contacting a portion of the metal foil with one or more power supply elements to apply a voltage to the metal foil in the presence of at least one of the first gas and the second gas.

[0026] I. First Aspect In this embodiment, the metal foil is heated, and the heat promotes the reaction of the second metal-containing molecules and / or the oxidizing agent with the metal foil surface, thereby forming a uniform dielectric layer.

[0027] [Film forming method] The film forming method according to the first embodiment includes a heating step of heating a metal foil. Fig. 1 is a flow chart showing the film forming method according to the first embodiment.

[0028] (Metal foil) The metal foil includes a first metal. The type of the first metal is not particularly limited. The first metal may be a valve metal such as aluminum (Al), tantalum (Ta), or niobium (Nb) or an alloy containing a valve metal, because it is easy to form a dielectric layer. The thickness of the metal foil is not particularly limited, but may be, for example, 10 μm or more and 300 μm or less, or 15 μm or more and 250 μm or less. The purity of the metal foil is not particularly limited. The purity of the metal foil may be, for example, 99% or more and 99.99% or less.

[0029] The surface of the metal foil may be roughened. Furthermore, another dielectric layer may be formed on the surface of the metal foil. For example, the metal foil may have another dielectric layer formed inside the pits formed by the roughening. The other dielectric coating may be formed, for example, by anodization.

[0030] (i) Surface modification step (S111) Before the first contact step, preferably before the heating step, a surface modification treatment may be performed to modify the surface of the metal foil. The surface modification treatment is performed to remove impurities from the metal foil surface and modify the surface condition of the metal foil. This improves the uniformity, adhesion, and density of the formed film, the effect of preventing diffusion of metal atoms in the metal foil, and the insulating properties, and further improves properties such as leakage current and capacitance. In particular, when the withstand voltage of the obtained electrode foil is 200V or less, or even 50V or less, the effect of the surface modification step is easily obtained.

[0031] The surface modification treatment is not particularly limited, and may be, for example, a plasma treatment or an atmospheric pressure plasma treatment. The surface modification treatment may be performed in the atmosphere or under reduced pressure. By the surface modification, for example, hydroxyl groups are added to the surface of the metal foil, or impurities such as organic substances are decomposed or vaporized.

[0032] (ii) Heating process (S112) In the heating step, the metal foil is brought into contact with a heating element. Metal foils generally have high heat resistance, so a method of heating by contact can be applied. Since atomic layer deposition (ALD) is performed in a reduced pressure atmosphere, heat transfer by convection cannot be expected. Therefore, the method of this embodiment, which can heat by utilizing thermal conduction, is suitable for the ALD method. A part of the metal foil is brought into contact with the heating element. Since the metal foil has high thermal conductivity, the entire metal foil can be heated quickly by bringing a part of it into contact with the heating element.

[0033] When heating, the metal foil may be pressed against the heating element by a pressing member disposed at a position corresponding to the heating element. This brings the metal foil and the heating element into closer contact, and the metal foil is heated efficiently. The pressing member is in contact with a part of the metal foil, similar to the heating element. The pressing member may be the heating element. By bringing the heating elements into contact with both main surfaces of the metal foil, the efficiency of heating is further improved.

[0034] The heating temperature is not particularly limited and may be appropriately set depending on the conditions of the method for forming the dielectric layer (atomic layer deposition method). The heating temperature is, for example, 80° C. or higher and 550° C. or lower.

[0035] When the metal foil contains aluminum, the heating temperature is preferably 90°C or more and 525°C or less. When the heating temperature is in this range, the effect of heating is easily obtained, and deformation of the metal foil is easily suppressed. In particular, when the metal foil is transported by roll to roll, the metal foil is subjected to stress from the rollers, etc., and pit deformation and plastic deformation are easily caused. If the metal foil is deformed, the transport becomes unstable and the film formation is easily non-uniform.

[0036] When the metal foil contains aluminum, the heating temperature is particularly preferably from 90° C. to 480° C. If the heating temperature is within this range, the pit-shaped deformation and plastic deformation can be further reduced.

[0037] (iii) First contact step (S113) The heated metal foil is brought into contact with a first gas containing a second metal while part of the foil is supported. This allows the first gas to come into contact with both main surfaces (both sides) of the metal foil. Molecules containing the second metal that were contained in the first gas adhere to both sides of the metal foil.

[0038] Examples of the second metal include Al, Ta, Nb, silicon (Si), titanium (Ti), zirconium (Zr), and hafnium (Hf). These may be used alone or in combination of two or more. That is, the dielectric layer may contain Al2O3, Ta2O5, Nb2O5, SiO2, TiO2, ZrO2, and HfO2 alone or in combination of two or more. When the dielectric layer contains two or more types of oxides of the second metal, the oxides may be mixed or may be arranged in layers. In particular, it is preferable that the second metal is a metal species different from the first metal contained in the metal foil. In particular, in terms of increasing the capacitance of the obtained electrolytic capacitor, it is preferable that the oxide of the second metal has a higher relative dielectric constant than the oxide of the first metal. In addition, in terms of improving the withstand voltage of the electrolytic capacitor, the oxide of the second metal is preferably Ta2O 5、 SiO 2、 ZrO2 and HfO2 are preferred.

[0039] The first gas contains a precursor containing the second metal in a gaseous state. The first gas may contain multiple types of precursors. Different types of precursors may be supplied to the chamber simultaneously or sequentially. Alternatively, the type of precursor contained in the first gas may be changed for each cycle.

[0040] The precursor is an organometallic compound containing a second metal, which makes the second metal more likely to be chemisorbed onto the target object. As the precursor, various organometallic compounds that have been used in the conventional ALD method can be used.

[0041] An example of a precursor containing Ti is bis(t-butylcyclopentadienyl)titanium(IV) dichloride (C 18 H 26 Cl2 Titanium(IV) diisopropoxide (Ti[OCC(CH3)3CHCOC(CH3)3]2(OC3H7)2), titanium(IV) ethoxide (Ti[O(C2H5)]4), and the like.

[0042] An example of the precursor containing Al is trimethylaluminum ((CH3)3Al). An example of the precursor containing Zr is bis(methyl-η5-cyclopentadienyl)methoxymethylzirconium (Zr(CH3C5H4)2CH3OCH3), tetrakis(dimethylamido)zirconium(IV) ([(CH3)2N]4Zr), tetrakis(ethylmethylamido)zirconium(IV) (Zr(NCH3C2H5)4). 、 Examples of precursors containing Nb include niobium(V) ethoxide (Nb(OCH2CH3)5, tris(diethylamido)(t-butylimido)niobium(V)(C 16 H 39 N4Nb) etc.

[0043] Examples of precursors containing Si include N-sec-butyl(trimethylsilyl)amine (CH 19 NSi), 1,3-diethyl-1,1,3,3-tetramethyldisilazane (CH 23NSi2), 2,4,6,8,10-pentamethylcyclopentasiloxane ((CH3SiHO)5), pentamethyldisilane ((CH3)3SiSi(CH3)2H), tris(isopropoxy)silanol ([(H3C)2CHO]3SiOH), chloropentanemethyldisilane ((CH3)3SiSi(CH3)2Cl), dichlorosilane (SiH2Cl2), tridimethylaminosilane (Si[N(CH3)2]4), tetraethylsilane (Si(C2H5)4), tetramethylsilane (Si(CH3)4), tetraethoxysilane (Si(OC2H5)4), dodecamethylcyclohexasilane ((Si(CH3)2)6), silicon tetrachloride (SiCl4), and silicon tetrabromide (SiBr4).

[0044] An example of a precursor containing Ta is tris(ethylmethylamido)(t-butylamido)tantalum(V) (C 13 H 33 N4Ta), tantalum(V) pentaethoxide (Ta(OC2H5)5), tris(diethylamido)(t-butylimido)tantalum(V) ((CH3)3CNTa(N(C2H5)2)3), and pentakis(dimethylamino)tantalum(V) (Ta(N(CH3)2)5).

[0045] Examples of precursors containing Hf include hafnium tetrachloride (HfCl4), tetrakis dimethylaminohafnium (Hf[N(CH3)2]4), tetrakis ethylmethylaminohafnium (Hf[N(C2H5)(CH3)]4), tetrakis diethylaminohafnium (Hf[N(C2H5)2]4), and hafnium t-butoxide (Hf[OC(CH3)3]4).

[0046] (iv) Second contact step (S114) After the first gas is exhausted (purged), the second gas is brought into contact with the metal foil. At this time, the metal foil is still partially supported. Therefore, the second gas can come into contact with both sides of the metal foil. Molecules containing the second metal that are attached to both sides of the metal foil react with the oxidizing agent contained in the second gas, producing an oxide of the second metal. As a result, a dielectric layer containing an oxide of the second metal is formed on both sides of the metal foil, without the need to switch the top and bottom sides of the metal foil.

[0047] The second gas includes an inert gas and an oxidizing agent. As the inert gas, an inert gas that has been conventionally used in the ALD method can be used. The inert gas is, for example, nitrogen or argon.

[0048] The oxidizing agent may be any oxidizing agent that has been used in the ALD method. Examples of the oxidizing agent include water, oxygen, ozone, hydrogen peroxide, and carbon dioxide. The oxidizing agent may be supplied to the reaction chamber as plasma using the oxidizing agent as a raw material.

[0049] The order of each step is not particularly limited. Usually, the first gas is brought into contact with the metal foil, and then the second gas is brought into contact with the metal foil. The first contact step may be carried out while heating the metal foil. The second contact step may be carried out while heating the metal foil.

[0050] The first contact step and the second contact step may be repeated multiple times. Specifically, the following may be repeated in the chamber: supply (pulse) of the first gas → exhaust (purge) of the first gas → supply (pulse) of the second gas → exhaust (purge) of the second gas. The type of the first gas and / or the second gas may be changed for each cycle. After a dielectric layer is formed by the first gas and the second gas, another dielectric layer may be formed by the first gas and the second gas.

[0051] In the ALD method, the second metal is deposited on the surface of the target object in atomic layers due to the self-limiting effect. Therefore, the thickness of the dielectric layer is controlled by the number of cycles, with the first contact step and the second contact step being one cycle. The thickness of the dielectric layer is not particularly limited, and may be, for example, 0.5 nm or more and 200 nm or less.

[0052] The heating step and the first and / or second contact steps are preferably performed in the same chamber. The same chamber does not include, for example, a case where 80% or more of the wall connecting the two chambers is physically blocked. This allows the metal foil to be quickly contacted with the first gas after being heated, so that the molecules containing the second metal and / or the oxidizing agent contained in the first gas are easily attached to the metal foil, and the film formation proceeds more efficiently.

[0053] [Electrode foil manufacturing method] The method for producing an electrode foil according to the first embodiment includes a heating step of contacting a part of a metal foil with one or more heating elements to heat the metal foil.

[0054] In the film forming method and electrode foil manufacturing method according to the first embodiment, both a metal foil having a predetermined size and a long metal foil are the film forming object. The electrode foil manufactured by the above method is suitably used as an anode body of an electrolytic capacitor.

[0055] Each step of the method for producing an electrode foil according to the first embodiment will be described in detail below. Fig. 2 is a flow chart showing the method for producing an electrode foil according to the first embodiment.

[0056] (1) Preparation process (S11) A metal foil similar to that described in the film forming method according to the first embodiment is prepared. The metal foil may have another dielectric layer formed inside the pits formed by roughening.

[0057] (2) Roughening process (S12) Before heating the metal foil, the surface of the metal foil may be roughened. By roughening, a plurality of pits are formed on the surface of the metal foil. In a later process, a dielectric layer is formed even inside the pits, which is expected to increase the capacitance. On the other hand, when the surface of the metal foil is roughened in this way, it is usually difficult to form a dielectric layer even inside the pits by a method other than anodization. By performing a heat treatment as in this embodiment, it becomes easy to form a uniform dielectric layer even inside the pits. When a dielectric layer containing an oxide of a second metal is formed and then anodized to form a third dielectric layer described later, it is preferable to perform this step. When the third dielectric layer to be formed has a porous structure, this step may be omitted.

[0058] The roughening is carried out, for example, by etching the metal foil. The etching is preferably carried out by electrolytic etching. The electrolytic etching is carried out by passing a direct current or an alternating current through the metal foil. The electrolytic etching is carried out, for example, in an aqueous hydrochloric acid solution.

[0059] The diameter of the pits formed on the surface of the metal foil is not particularly limited. The diameter of the pits is preferably 50 nm or more and 2000 nm or less, since the surface area is likely to become large. From the viewpoint of the contact between the metal foil and the heating element or the transport roll, it is preferable that the diameter of the pits is not excessively large. The diameter of the pits is more preferably 80 nm or more and 1300 nm or less. The diameter of the pits is, for example, the most frequent pore size of the pore distribution measured by a mercury porosimeter (hereinafter the same).

[0060] The thickness of the etching layer formed by the plurality of pits is not particularly limited, and may be appropriately set according to the thickness of the metal foil. When the metal foil is used as an anode of an electrolytic capacitor, from the viewpoint of capacitance, the thickness of the etching layer is preferably 5 μm or more, more preferably 15 μm or more. When the thickness of the etching layer is within this range, the effect of heating is easily obtained. From the viewpoint of the strength of the metal foil, the thickness of the etching layer is preferably 100 μm or less, more preferably 80 μm or less. The thickness of the etching layer is the thickness of the etching layer formed on one main surface of the metal foil. The thickness of the etching layer is the average value of any 10 points in an SEM or TEM image of the cross section of the metal foil. The thickness of the dielectric layer is calculated in the same manner (hereinafter the same).

[0061] Figure 3 is an SEM image (300x) of a cross section of a roughened metal foil according to the present embodiment. In Figure 3, the area in the center shown in light grey is the less porous core. The core is the unetched area of ​​the metal foil. The area adjacent to the core shown in dark grey is the etched layer. The etched layer is formed on each of the two main sides of the metal foil. The area outside the etched layer shown in black is the background.

[0062] (3) Surface modification process (S13) Before the first contact step, preferably before the heating step, a surface modification treatment for modifying the surface of the metal foil may be carried out in the same manner as the (i) surface modification step in the film forming method according to the first embodiment.

[0063] (4)Heating process (S14) The metal foil is heated in the same manner as in the heating step (ii) in the film forming method according to the first embodiment. The metal foil is heated by bringing a heating element into contact with a part of the metal foil. The metal foil is preferably heated in a chamber to which the first gas is supplied. The pressure in the chamber may be reduced during heating.

[0064] (5) First Contacting Step (S15) and Second Contacting Step (S16) Using the above-mentioned film-forming apparatus, the first gas and the second gas are brought into contact with both sides of the metal foil, respectively. Each contact step is carried out in the same manner as the (iii) first contact step and the (iv) second contact step in the film-forming method according to the first embodiment. As a result, a dielectric layer containing an oxide of the second metal is formed on both sides of the metal foil.

[0065] After forming the dielectric layer, the metal foil may be chemically converted. As a result, a third dielectric layer containing an oxide of the first metal constituting the metal foil is formed between the metal foil and the dielectric layer. This makes it easier to form a layer with a uniform thickness without pinholes as a whole dielectric layer. The method of chemically converting the metal foil is not particularly limited. The chemical conversion is performed, for example, by immersing the metal foil in a chemical conversion solution and applying a voltage (anodic oxidation).

[0066] [Film forming equipment] The film forming apparatus according to the first aspect includes a heating element disposed in a chamber and contacting a part of a metal foil as a film forming target to heat the metal foil. A first gas and a second gas are supplied to the metal foil so as to contact both main surfaces of the metal foil.

[0067] (heating element) The heating element heats the metal foil by contacting a part of the metal foil, which is the object of film formation. There may be one or more heating elements, and there may be two or more heating elements. The shape of the heating element is not particularly limited as long as it can contact the metal foil over a certain area. The heating element may be, for example, a stage that supports the metal foil, a transport roll, or a positioning member that positions the metal foil.

[0068] (Chamber) The deposition apparatus includes at least one chamber. The film forming apparatus may include one chamber to which the first gas and the second gas can be supplied and exhausted.

[0069] The deposition apparatus may include a plurality of chambers capable of supplying and exhausting the first gas and the second gas. In this case, the same type of first gas may be supplied to the plurality of chambers, or a plurality of types of first gases containing different second metals may be supplied to each of the plurality of chambers. The same type of second gas may be supplied to the plurality of chambers, or a plurality of types of second gases containing different oxidizing agents may be supplied to each of the plurality of chambers. However, it is sufficient that the heating element is disposed in at least one of the plurality of chambers.

[0070] The film forming apparatus may include a first chamber to which a first gas can be supplied and exhausted, and a second chamber to which a second gas can be supplied and exhausted. However, the heating element may be disposed in at least one of these chambers. Preferably, the heating element is disposed in the first chamber.

[0071] The film forming apparatus may include a plurality of the first chambers and / or second chambers. In this case, the same type of first gas may be supplied to the plurality of first chambers, or a plurality of types of first gases containing different second metals may be supplied to each of the plurality of second chambers. The same type of second gas may be supplied to the plurality of second chambers, or a plurality of types of second gases containing different oxidizing agents may be supplied to each of the plurality of second chambers. However, it is sufficient that the heating element is disposed in at least one of the plurality of chambers. Preferably, the heating element is disposed in at least one of the first chambers.

[0072] From the viewpoint of productivity, it is preferable that the deposition apparatus has at least one chamber to which the first gas and the second gas can be supplied and exhausted, so that the formation of at least one dielectric layer is completed in one chamber.

[0073] (Pressure control section) The chamber includes a pressure control unit that controls the pressure in the chamber to a reduced pressure atmosphere. The pressure control unit includes, for example, a computer.

[0074] (supply and exhaust) The chamber includes a first supply port for supplying a first gas into the chamber and a first exhaust port for exhausting the first gas. The chamber includes a second supply port for supplying a second gas into the chamber and a second exhaust port for exhausting the second gas. The first gas and the second gas may be supplied from the same supply port. The first gas and the second gas may be exhausted from the same exhaust port.

[0075] (Support) The chamber may include a support that supports the metal foil in contact with a part of the metal foil, in addition to the heating element. The number of supports may be one or more, and may be two or more. The shape of the support is not particularly limited as long as it can stably support the metal foil. The support may be, for example, a stage that supports the metal foil, a transport roll, or a positioning member that positions the metal foil.

[0076] (Holding member) The chamber may further include a pressing member disposed at a position corresponding to the heating element for pressing the metal foil toward the heating element. This brings the metal foil and the heating element into close contact with each other, and the metal foil is efficiently heated. The pressing member contacts a portion of the metal foil, similar to the heating element. The pressing member may be the heating element. By contacting both main surfaces of the metal foil with the heating element, the efficiency of heating is further improved.

[0077] The film forming method and film forming apparatus according to the first aspect can form a film on a metal foil having a predetermined size or on a long metal foil. The long metal foil is transported, for example, in a chamber, and a dielectric layer is continuously formed on the transported metal foil.

[0078] Below, the film-forming apparatus of the first embodiment will be described, divided into a case in which the metal foil cut to a predetermined size in advance is used as the film-forming object (hereinafter referred to as the batch method), and a case in which the metal foil is a long length of metal foil (hereinafter referred to as the roll-to-roll method).

[0079] A. Batch method In this embodiment, the heating element is, for example, a stage. The metal foil is heated by being placed on the stage in the chamber. The stage is in contact with a part of the metal foil.

[0080] [Iith embodiment] FIG. 4 is a side view conceptually showing an example of a film forming apparatus according to the first embodiment, which is used in a batch system.

[0081] The film forming apparatus 10A includes a chamber 11 capable of supplying and discharging a first gas and a second gas. The chamber 11 includes a first supply port 121 for supplying the first gas G1 into the chamber 11 and a second supply port 122 for supplying the second gas G2 into the chamber 11. The chamber 11 further includes an exhaust port 13 for discharging the first gas G1 and the second gas G2. The first gas G1 and the second gas G2 may be exhausted from different exhaust ports.

[0082] The pressure inside the chamber 11 is controlled by a pressure control unit 16. When the first gas G1 and the second gas G2 are supplied into the chamber 11, the pressure control unit 16 controls the inside of the chamber 11 to be a reduced pressure atmosphere.

[0083] A stage 14 is disposed within the chamber 11. The stage 14 has a flat portion that contacts the metal foil 100. The metal foil 100 is placed on the stage 14 so that a portion of the metal foil 100 is in contact with the stage 14. The metal foil 100 has an appropriate rigidity and is supported by the stage 14 without excessive sagging or loosening. The stage 14 is a heating element 19. The metal foil 100 has good thermal conductivity and therefore the entirety of the metal foil 100 can be quickly heated by the stage 14 that is in contact with a portion of the metal foil 100.

[0084] Since the metal foil 100 is supported in a substantially planar state by the stage 14, the first gas G1 and the second gas G2 supplied into the chamber 11 can contact both main surfaces of the metal foil 100. As a result, at least one dielectric layer is formed on both main surfaces of the metal foil 100 by a single treatment.

[0085] A pressing member 15 for pressing the metal foil 100 towards the stage 14 is disposed at a position corresponding to the stage 14. The pressing member 15 has a flat portion that comes into contact with the metal foil 100. The pressing member 15 may be a heating element 19.

[0086] [I-ii embodiment] 5 is a side view conceptually showing another example of the film forming apparatus according to the first embodiment. The film forming apparatus 10B has the same configuration as the film forming apparatus 10A, except that it has a plurality of stages 14. At least one of the stages 14 is a heating element 19.

[0087] B. Roll-to-roll method In this embodiment, the heating element contacts a portion of the metal foil being transported in the first chamber. The metal foil is heated while being transported. The heating element may be a transport roll, a positioning member for positioning the metal foil being transported, or a stage for supporting the metal foil being transported.

[0088] When the first gas and the second gas are supplied and exhausted in one chamber, the chamber may be divided into multiple zones. For example, the chamber may include a first supply zone to which the first gas is supplied, a second supply zone to which the second gas is supplied, a first exhaust zone to which the first gas is purged, and a second exhaust zone to which the second gas is purged. Each zone is divided by, for example, a wall of an inert gas (nitrogen, argon, etc.). However, the above multiple zones can be considered as one space. Furthermore, the parts of the chamber other than the above zones also form one space together with the above multiple zones. The metal foil may pass through each zone multiple times.

[0089] [I-iii embodiments] FIG. 6 is a side view conceptually showing an example of a film forming apparatus according to the first embodiment, which is used in a roll-to-roll system.

[0090] The film forming apparatus 20A includes a chamber 21 that can supply and exhaust a first gas and a second gas. The chamber 21 includes a first supply zone SZ1 to which a first gas G1 is supplied, a second supply zone SZ2 to which a second gas G2 is supplied, a first exhaust zone EZ1 to purge the first gas G1, and a second exhaust zone EZ2 to purge the second gas G2. The zones are arranged in this order so as to separate the chamber 21 in a direction intersecting the transport direction.

[0091] The chamber 21 includes a first supply port 221 that supplies a first gas G1 to the first supply zone SZ1 and a second supply port 222 that supplies a second gas G2 to the second supply zone SZ2. The chamber 21 includes a first exhaust port 231 that exhausts the first gas G1 from the first exhaust zone EZ1 and a second exhaust port 232 that exhausts the second gas G2 from the second exhaust zone EZ2.

[0092] A stage 241 that supports the transported metal foil 200 is disposed upstream of the chamber 21. The stage 241 is a heating element 29. The stage 241 has a flat portion that contacts the metal foil 200. The heating element 29 is disposed upstream of the first supply zone SZ1. The heating element 29 may be disposed in the first supply zone SZ1, which is the most upstream zone. The heating element 29 may further be disposed in at least one of the first exhaust zone EZ1, the second supply zone SZ2, and the second exhaust zone EZ2.

[0093] An inert gas G3 (for example, nitrogen gas) is supplied to the first exhaust zone EZ1 from the third supply port 223. This separates the first supply zone SZ1 from the second supply zone SZ2, and purges the unreacted first gas G1 from the first exhaust port 231.

[0094] Similarly, the inert gas G3 is supplied from the third supply port 223 to the second exhaust zone EZ2. This separates the second supply zone SZ2 from other parts of the chamber 21, and the unreacted second gas G2 is purged from the second exhaust port 232. The third gas G3 supplied to the first exhaust zone EZ1 and the second exhaust zone EZ2 may be the same or different. Purging from each exhaust port is performed appropriately. The exhaust port to be used may be determined as necessary. Further exhaust ports may be added as necessary.

[0095] The film forming apparatus 20A may have multiple combinations of a first supply zone SZ1, a first exhaust zone EZ1, a second supply zone SZ2, and a second exhaust zone EZ2 depending on the desired thickness of the dielectric layer. The first gas G1 supplied in the multiple first supply zones SZ1 may be the same or different. The second gas G2 supplied in the multiple second supply zones SZ2 may be the same or different.

[0096] Metal foil 200 may pass through multiple combinations of first supply zone SZ1, first exhaust zone EZ1, second supply zone SZ2, and second exhaust zone EZ2 depending on the desired thickness of the dielectric layer.

[0097] The pressure in the chamber 21 is controlled by the pressure control unit 26 so as to create a reduced pressure atmosphere. The pressure control unit 26 may appropriately control the pressure in each zone.

[0098] The metal foil 200 is wound around a supply reel 201 that is driven to rotate by a motor, and is supplied to the upstream side of the chamber 21 while being unwound from the supply reel 201. The metal foil 200 comes into contact with a stage 241 (heating element 29) upstream of the chamber 21 and is heated, and then is transported downstream.

[0099] A pressing member 25 for pressing the metal foil 200 toward the stage 241 is disposed at a position corresponding to the stage 241. The pressing member 25 is in a roll shape and supports the transportation of the metal foil 200. The pressing member 25 may be a heating element.

[0100] In another embodiment, the stage 241 is not a heating element, and the holding member 25 is a heating element.

[0101] The heated metal foil 200 is first carried into a first supply zone SZ1. In the first supply zone SZ1, a first gas G1 is supplied from a first supply port 221 to both sides of the metal foil 200, and molecules containing a second metal adhere to both sides of the metal foil 200.

[0102] Next, the metal foil 200 is carried into the first exhaust zone EZ1. In the first exhaust zone EZ1, an inert gas G3 is supplied from a third supply port 223, and the unreacted first gas G1 is exhausted from a first exhaust port 231.

[0103] Next, the metal foil 200 is carried into the second supply zone SZ2. In the second supply zone SZ2, a second gas G2 is supplied to both sides of the metal foil 200 from the second supply port 222. Molecules containing the second metal attached to both sides of the metal foil 200 react with the oxidizing agent to generate a dielectric layer containing an oxide of the second metal. As a result, a dielectric layer containing an oxide of the second metal is formed on both sides of the metal foil 200.

[0104] Finally, the metal foil 200 is carried into the second exhaust zone EZ2. In the second exhaust zone EZ2, an inert gas G3 is supplied from a third supply port 223, and the unreacted second gas G2 is exhausted from a second exhaust port 232.

[0105] After a desired thickness of oxide has been deposited on the metal foil 200, the metal foil 200 is removed from the chamber 21 and taken up by a recovery reel 202. The recovery reel 202 is driven to rotate by a motor.

[0106] [I-iv embodiments] 7 is a side view conceptually showing the main part of another film forming apparatus according to embodiment 1. Film forming apparatus 20B has the same configuration as film forming apparatus 20A, except for the shape and arrangement of the heating elements.

[0107] In the film forming apparatus 20B, the metal foil 200 unwound from the supply reel 201 is placed on the conveyor belt 28 and conveyed upstream of the chamber 21. A positioning member 243 for fixing and positioning the metal foil 200 is disposed on the conveyor belt 28. The metal foil 200 has one or more through holes 200a formed therein, and the metal foil 200 is positioned by inserting the positioning member 243 into the through holes 200a. The positioning member 243 is a heating element 29. Therefore, the metal foil 200 comes into contact with the positioning member 243 around the through holes 200a and is heated. Thereafter, the metal foil 200 is released from the conveyor belt 28 and conveyed to the first supply zone SZ1 by the conveyor roll 27. Thereafter, the metal foil 200 is treated in the same manner as in the film forming apparatus 20A, and a dielectric layer is formed on both sides.

[0108] [Embodiment IV] 8 is a side view conceptually showing another example of the film forming apparatus according to the first embodiment. The film forming apparatus 20C has the same configuration as the film forming apparatus 20A, except for the shape of the heating element.

[0109] In the film forming apparatus 20C, the metal foil 200 unwound from the supply reel 201 is carried into the first supply zone SZ1 by the transport roll 27. The transport roll 27 is a heating element 29. Therefore, the metal foil 200 is heated while being transported by the transport roll 27. A roll-shaped pressing member 25 is disposed at a position corresponding to the transport roll 27. The pressing member 25 may be a heating element 29. The metal foil 200 is then transported to the first supply zone SZ1. Thereafter, the metal foil 200 is treated in the same manner as in the film forming apparatus 20A, and a dielectric layer is formed on both sides.

[0110] [Embodiments I-vi] FIG. 9 is a side view conceptually showing another example of the film forming apparatus according to the first embodiment. The film forming apparatus 20D includes a chamber 21 that can supply and exhaust a first gas and a second gas. The metal foil 200 is transported while being folded back multiple times within the chamber 21. The number of times the metal foil is folded back is not particularly limited.

[0111] The chamber 21 includes a first supply zone SZ1 to which a first gas G1 is supplied, a second supply zone SZ2 to which a second gas G2 is supplied, and an exhaust zone EZ for purging the first gas G1 and the second gas G2. Each zone is arranged to separate the chamber 21 along the transport direction. A plurality of first transport rolls 271 are arranged in the first supply zone SZ1. A plurality of second transport rolls 272 are arranged in the second supply zone SZ2. At least one of the first transport roll 271 and the second transport roll 272 is a heating element 29. A third transport roll 273 arranged in the exhaust zone EZ may be a heating element 29.

[0112] The metal foil 200 is supplied upstream within the chamber 21 while being unwound from the supply reel 201. The metal foil 200 is changed in direction by the third transport roll 273 and carried into the first supply zone SZ1. In the first supply zone SZ1, a first gas G1 is supplied from a first supply port 221 to both sides of the metal foil 200, and molecules containing the second metal adhere to both sides of the metal foil 200.

[0113] The metal foil 200 is folded back by the first transport roll 271 and carried into the exhaust zone EZ. In the exhaust zone EZ, an inert gas G3 (e.g., nitrogen gas) is supplied from the third supply port 223, and the unreacted first gas G1 is purged from the exhaust port 23. An exhaust port may be added, for example, to the first supply zone SZ1 and / or the second supply zone SZ2, as necessary.

[0114] Next, the metal foil 200 is carried into the second supply zone SZ2. In the second supply zone SZ2, a second gas G2 is supplied to both sides of the metal foil 200 from a second supply port 222. Molecules containing the second metal attached to both sides of the metal foil 200 react with the oxidizing agent to generate an oxide of the second metal. As a result, a dielectric layer containing an oxide of the second metal is formed on both sides of the metal foil 200.

[0115] The metal foil 200 is folded back by the second transport roll 272 and is again carried into the exhaust zone EZ. In the exhaust zone EZ, the unreacted second gas G2 is also purged from the exhaust port 23.

[0116] The metal foil 200 is then transported back into the first supply zone SZ1. Thereafter, the metal foil 200 is repeatedly transported into and out of the first supply zone SZ1, exhaust zone EZ, and second supply zone SZ2, and an oxide of a desired thickness is deposited on the metal foil 200. Finally, the metal foil 200 is transported out of the chamber 21 and wound up on the recovery reel 202.

[0117] II. Second Aspect In this embodiment, a voltage is applied to the metal foil in the presence of the first gas. This allows the molecules containing the second metal to be electrically attracted to the metal foil, increasing the concentration of the second metal near the metal foil. As a result, the reaction efficiency is improved and a uniform dielectric layer is formed. In addition, the molecules containing the second metal are used efficiently. Furthermore, the second metal is more easily adsorbed to the metal foil, improving the density of the layer containing the metal oxide that is formed.

[0118] [Film forming method] The film forming method according to the second embodiment includes a first application step (hereinafter simply referred to as an application step) of applying a voltage to a metal foil in the presence of a first gas. Fig. 10 is a flowchart showing the film forming method according to the second embodiment.

[0119] The film forming method according to the second aspect includes the same steps as the (iii) first contact step and the (iv) second contact step in the film forming method according to the first aspect, except that it includes an application step instead of a heating step. The film forming method according to the second aspect may include the same step as the (i) surface modification step in the film forming method according to the first aspect.

[0120] (i) Surface modification process (S211) The surface of the metal foil may be modified in the same manner as in the surface modification step (i) in the film formation method according to the first embodiment.

[0121] (ii) First Contacting Step (S212) and Applying Step (S214) In the same manner as in the (iii) first contact step in the film forming method according to the first embodiment, the metal foil is brought into contact with the first gas containing the second metal. At this time, a voltage is applied to the metal foil in contact with one or more first power feeders (hereinafter simply referred to as power feeders). The contact of the power feeders with the metal foil may be performed inside or outside the chamber.

[0122] The voltage application to the metal foil is performed by generating a potential difference between the electrode foil and the counter electrode. The voltage difference can be generated using a constant voltage, a pulsed voltage, a waveform superimposed with an alternating current, or other irregular waveforms. The voltage difference is not particularly limited. The voltage difference is preferably 5V or more and 1000V or less, and more preferably 10V or more and 800V or less. If the potential difference is within this range, the effect of the voltage application can be easily obtained, and damage to the metal foil and the film forming device can be easily suppressed.

[0123] A voltage may be applied to the metal foil as a positive electrode or as a negative electrode, and the polarity of the metal foil may be appropriately set according to the charged state of the first gas.

[0124] (iii) Second contact step (S213) The second gas is brought into contact with the metal foil in the same manner as in the (iv) second contacting step in the film forming method according to the first embodiment, whereby a layer containing a metal oxide is formed on the surface of the metal foil.

[0125] The order of each step is not particularly limited. Usually, the first gas is brought into contact with the metal foil, and then the second gas is brought into contact with the metal foil. The first contact step and the second contact step may be repeatedly performed multiple times.

[0126] [Electrode foil manufacturing method] The method for producing an electrode foil according to the second embodiment includes a step of applying a voltage to a metal foil in the presence of a first gas.

[0127] In the film forming method and electrode foil manufacturing method according to the second embodiment, both a metal foil having a predetermined size and a long metal foil are the film forming object. The electrode foil manufactured by the above method is suitably used as an anode body of an electrolytic capacitor.

[0128] Each step of the method for producing an electrode foil according to the second embodiment will be described in detail below. Fig. 11 is a flowchart showing the method for producing an electrode foil according to the second embodiment.

[0129] (1) Preparation process (S21) A metal foil similar to that described in the film forming method according to the first embodiment is prepared. The metal foil may have another dielectric layer formed inside the pits formed by roughening.

[0130] (2) Roughening step (S22) Before the first contact step, the surface of the metal foil may be roughened. The roughening is performed in the same manner as in the (2) roughening step in the manufacturing method of the electrode foil according to the first embodiment. Usually, when the surface of the metal foil is roughened in this manner, it is difficult to form a dielectric layer even inside the pits by a method other than anodization. By applying a voltage as in this embodiment, it becomes easy to form a uniform dielectric layer even inside the pits. When a dielectric layer containing an oxide of a second metal is formed and then anodized to form a third dielectric layer described later, it is preferable to perform this step. When the third dielectric layer to be formed has a porous structure, this step may be omitted.

[0131] The diameter of the pits formed on the surface of the metal foil is not particularly limited. The diameter of the pits is preferably 50 nm or more and 2000 nm or less, since the surface area is likely to be large. From the viewpoint of the contact between the metal foil and the power supply, it is preferable that the diameter of the pits is not excessively large. The diameter of the pits is more preferably 80 nm or more and 1300 nm or less. If the diameter of the pits is within this range, the metal foil and the power supply are likely to come into contact with each other, and a voltage is likely to be applied uniformly to the metal foil.

[0132] The thickness of the etching layer is not particularly limited, and may be appropriately set according to the thickness of the metal foil. When the metal foil is used as an anode of an electrolytic capacitor, the thickness of the etching layer is preferably 5 μm or more, more preferably 15 μm or more, from the viewpoint of capacitance. When the thickness of the etching layer is within this range, the effect of voltage application is easily obtained. From the viewpoint of the strength of the metal foil, the thickness of the etching layer is preferably 100 μm or less, more preferably 80 μm or less.

[0133] (3) Surface modification process (S23) Before the first contact step, a surface modification treatment may be carried out to modify the surface of the metal foil. The surface modification step is carried out in the same manner as the surface modification step (i) in the film forming method according to the first embodiment.

[0134] (4) First Contact Step (S24) and Application Step (S26) This is carried out in the same manner as in the (ii) first contact step and the application step in the film forming method according to the second embodiment.

[0135] (5) Second contact process (S25) This is carried out in the same manner as in the (iii) second contact step in the film forming method according to the second embodiment, whereby dielectric layers containing an oxide of the second metal are formed on both sides of the metal foil.

[0136] After forming the dielectric layer, the metal foil may be chemically converted. As a result, a third dielectric layer containing an oxide of the first metal constituting the metal foil is formed between the metal foil and the dielectric layer. This makes it easier to form a layer with a uniform thickness without pinholes as the whole dielectric layer. The method for chemically converting the metal foil is not particularly limited. The chemical conversion is performed, for example, by anodization.

[0137] III. Third Aspect In this embodiment, a voltage is applied to the metal foil in the presence of the second gas. This electrically attracts the oxidizing agent to the metal foil, increasing the oxygen concentration near the metal foil. As a result, the metal foil is easily oxidized, and a uniform dielectric layer is formed. In addition, the oxidizing agent is used efficiently. Furthermore, the oxidizing agent is easily adsorbed to the metal foil, improving the density of the layer containing the metal oxide that is formed.

[0138] [Film forming method] The film forming method according to the third embodiment includes a second applying step (hereinafter simply referred to as the applying step) of applying a voltage to the metal foil in the presence of a second gas. Fig. 12 is a flow chart showing the film forming method according to the third embodiment.

[0139] The film formation method according to the third embodiment includes the same steps as the film formation method and the electrode foil manufacturing method according to the second embodiment, except that the voltage is applied in the presence of a second gas instead of a first gas.

[0140] (i) Surface modification process (S311) The surface of the metal foil may be modified in the same manner as in the surface modification step (i) in the film formation method according to the second embodiment.

[0141] (ii) First contact step (S312) In the same manner as in the (ii) first contacting step in the film forming method according to the second embodiment, the metal foil is brought into contact with the first gas containing the second metal.

[0142] (iii) Second contact step (S313) and application step (S314) The second gas is brought into contact with the metal foil in the same manner as in the (iii) second contact step in the film forming method according to the first embodiment. At this time, a part of the metal foil is brought into contact with one or more second power feeders (hereinafter simply referred to as power feeders) and a voltage is applied to the metal foil. As a result, a layer containing a metal oxide is formed on the surface of the metal foil. The contact of the power feeders with the metal foil may be performed inside or outside the chamber.

[0143] The order of each step is not particularly limited. Usually, the first gas is brought into contact with the metal foil, and then the second gas is brought into contact with the metal foil. The first contact step and the second contact step may be repeatedly performed multiple times.

[0144] After forming the dielectric layer, the metal foil may be chemically converted. As a result, a third dielectric layer containing an oxide of the first metal constituting the metal foil is formed between the metal foil and the dielectric layer. This makes it easier to form a layer with a uniform thickness without pinholes as the whole dielectric layer. The method for chemically converting the metal foil is not particularly limited. The chemical conversion is performed, for example, by anodization.

[0145] [Electrode foil manufacturing method] The method for producing an electrode foil according to the third embodiment includes a step of applying a voltage to the metal foil in the presence of a second gas.

[0146] In the film forming method and electrode foil manufacturing method according to the third embodiment, both a metal foil having a predetermined size and a long metal foil are the film forming object. The electrode foil manufactured by the above method is suitably used as an anode body of an electrolytic capacitor.

[0147] Each step of the method for producing an electrode foil according to the third embodiment will be described in detail below. Fig. 13 is a flowchart showing the method for producing an electrode foil according to the third embodiment.

[0148] (1) Preparation process (S31) A metal foil similar to that described in the film forming method according to the first embodiment is prepared. The metal foil may have another dielectric layer formed inside the pits formed by roughening.

[0149] (2) Roughening step (S32) Prior to the first contact step, the surface of the metal foil may be roughened in the same manner as in the (2) roughening step in the method for producing an electrode foil according to the first embodiment.

[0150] (3) Surface modification process (S33) Before the first contact step, a surface modification treatment may be carried out to modify the surface of the metal foil. The surface modification step is carried out in the same manner as the (i) surface modification step in the film forming method according to the first embodiment.

[0151] (4) First contact step (S34) This is carried out in the same manner as in the (ii) first contact step in the film-forming method according to the third embodiment.

[0152] (5) Second contact step (S35) and second application step (S36) This is carried out in the same manner as the (iii) second contact step and the second application step in the film forming method according to the third embodiment.

[0153] The voltage application to the electrode foil may be performed both in the presence of the first gas and in the presence of the second gas. This results in a more uniform layer. Fig. 14 is a flow chart showing the film forming method according to this embodiment. Fig. 15 is a flow chart showing the manufacturing method of the electrode foil according to this embodiment.

[0154] This embodiment differs from the second embodiment in that (iii) a voltage is applied to the metal foil in the second contact step, and differs from the third embodiment in that (ii) a voltage is applied to the metal foil in the first contact step. Other than these, this embodiment has the same steps as the second and third embodiments.

[0155] [Film forming equipment] The film forming apparatus according to the second and third aspects includes a power supply body that contacts a part of a metal foil that is a film forming target, and a counter electrode that generates a voltage difference between the metal foil and the power supply body. The first gas and the second gas are supplied so as to contact both main surfaces of the metal foil.

[0156] (power feeder) The power feeders (first and second power feeders) contact a part of the metal foil, which is the object to be film-formed, to apply a voltage to the metal foil. There may be one or more power feeders, and there may be two or more power feeders. The shape of the power feeder is not particularly limited as long as it can contact the metal foil over a certain area.

[0157] The power supply body may be, for example, a supply reel and / or a recovery reel, a stage for supporting the metal foil, a transport roll, or a positioning member for positioning the metal foil. When forming a film by roll-to-roll, the power supply body may be located inside or outside the chamber. In terms of reducing energy loss, it is preferable that the power supply body is located inside the chamber, particularly near the contact point between the metal foil and the first and / or second gas. On the other hand, in consideration of ease of maintenance and freedom of device design, it is preferable that the power supply body is located outside the chamber.

[0158] (opposite) The counter electrode is used together with the power supply body to generate a voltage difference between the metal foil and the power supply body. The arrangement of the counter electrode is not particularly limited, and may be at a location where a voltage is applied to at least both sides of the metal foil. The counter electrode does not have to face the main surface of the metal foil. There may be one or more counter electrodes, and there may be two or more counter electrodes. The shape of the counter electrode is also not particularly limited.

[0159] The distance between the metal foil and the counter electrode is not particularly limited. The distance between the metal foil and the counter electrode is preferably 0.5 mm or more and 500 mm or less. If the distance between the metal foil and the counter electrode is within this range, the distance between the metal foil and the counter electrode is easily maintained constant when the metal foil is transported. Therefore, it is easy to avoid the applied voltage from being locally high or the metal foil and the counter electrode from contacting each other. Furthermore, a uniform layer is easily formed. The distance between the metal foil and the counter electrode is more preferably 1 mm or more and 200 mm or less, and particularly preferably 1 mm or more and 130 mm or less. If the distance between the metal foil and the counter electrode is within this range, the equipment can be made small and energy loss can be reduced. When there are multiple counter electrodes, the distance between the metal foil and each counter electrode does not have to be the same.

[0160] When there are multiple chambers, the counter electrode only needs to be disposed in at least one of the chambers.

[0161] The film-forming apparatus according to the second and third aspects includes a chamber, a pressure control unit, a supply port, and an exhaust port similar to those of the film-forming apparatus according to the first aspect, except that the film-forming apparatus according to the second and third aspects includes a power supply body instead of a heating body. The film-forming apparatus according to the second and third aspects may include a support, a pressing member, etc., in the film-forming apparatus according to the first aspect.

[0162] The second mode is executed when a voltage is applied to the power supply while the metal foil is in contact with the first gas, and the third mode is executed when a voltage is applied to the power supply while the metal foil is in contact with the second gas.

[0163] In the film forming method and film forming apparatus according to the second and third aspects, a metal foil having a predetermined size can be used as a film forming target, or a long metal foil can be used as a film forming target. The long metal foil is, for example, transported in a chamber, and a dielectric layer is continuously formed on the transported metal foil.

[0164] Hereinafter, similarly to the first embodiment, the film forming apparatus according to the second and third embodiments will be described separately for the batch type and the roll-to-roll type.

[0165] A. Batch method In this embodiment, the power supply (first and / or second power supply) is, for example, a stage. A counter electrode is disposed near the metal foil. By placing the metal foil on the stage in the chamber, it becomes possible to apply a voltage to the metal foil and generate a potential difference between the metal foil and the counter electrode. The stage contacts a part of the metal foil.

[0166] [II-i embodiment] FIG. 16 is a side view conceptually showing an example of a film forming apparatus according to the second and third embodiments, which is used in a batch system.

[0167] The film forming apparatus 30 has the same configuration as the film forming apparatus 10A shown in FIG. 4, except that it includes a stage 34 also serving as a power feeder 39 and a counter electrode 38 instead of the stage also serving as a heating element.

[0168] That is, the film forming apparatus 30 includes a chamber 31. The chamber 31 includes a first supply port 321, a second supply port 322, and an exhaust port 33. The pressure inside the chamber 31 is controlled by a pressure control unit 36. The metal foil 300 is pressed against a stage 34 by a pressing member 35.

[0169] The film forming apparatus 30 further includes a voltage regulator 303 and an AC power supply 304. However, these are installed optionally.

[0170] The counter electrode 38 is arranged so that a voltage is applied to both sides of the metal foil with one sheet. However, the arrangement of the counter electrodes is not limited thereto, and for example, multiple counter electrodes may be arranged so as to face both main surfaces of the metal foil. When multiple counter electrodes are arranged, it is preferable to arrange them so as to be point-symmetric or line-symmetric with respect to the metal foil.

[0171] B. Roll-to-roll method In this embodiment, a voltage is applied to the metal foil being transported. The power supply is disposed inside or outside the chamber. The power supply may be a supply or return reel, a transport roll, a positioning member for positioning the metal foil being transported, or a stage for supporting the metal foil being transported.

[0172] When the first gas and the second gas are supplied and exhausted within one chamber, the chamber may be divided into a plurality of zones, as in the first embodiment. The metal foil may pass through each zone a plurality of times.

[0173] [II-ii embodiment] FIG. 17 is a side view conceptually showing an example of a film forming apparatus according to the second and third embodiments, which is used in a roll-to-roll system.

[0174] Film forming apparatus 40A has the same configuration as film forming apparatus 20A shown in FIG. 6, except that it includes third transport roll 473 also serving as power supply 49 and counter electrode 48 instead of the stage also serving as a heating element.

[0175] That is, the film forming apparatus 40A includes a chamber 41. The chamber 41 includes a first supply zone SZ1 to which a first gas G1 is supplied, a second supply zone SZ2 to which a second gas G2 is supplied, a first exhaust zone EZ1 to purge the first gas G1, and a second exhaust zone EZ2 to purge the second gas G2. The zones are arranged in this order so as to separate the chamber 21 in a direction intersecting the transport direction. In each zone, a first supply port 421, a second supply port 422, a third supply port 423, a first exhaust port 431, and a second exhaust port 432 are appropriately provided. Purging from each exhaust port is appropriately performed. The exhaust port to be used may be determined as necessary.

[0176] At least one counter electrode may be disposed on each of the main surfaces of the metal foil so as to face each of the main surfaces. In this case, the variation in the voltage applied to the metal foil is suppressed. The counter electrodes may be disposed in the first supply zone SZ1 and / or the second supply zone SZ2.

[0177] The pressure in the chamber 41 is controlled by a pressure control unit 46 to create a reduced pressure atmosphere. The pressure control unit 46 may appropriately control the pressure in each zone. The metal foil 400 is wound around a supply reel 401 that is driven to rotate by a motor, and is supplied upstream in the chamber 41 while being unwound from the supply reel 401. After processing, the metal foil 400 is collected by a collection reel 402.

[0178] A third transport roll 473 for transporting the metal foil 400 is disposed on the upstream side of the chamber 21. The third transport roll 473 is a power feeder 49. The power feeder 49 is disposed upstream of a first supply zone SZ1 in the chamber 41. The metal foil 400 is transported while being supported by the power feeder 49 (third transport roll 473). The counter electrode 48 is disposed downstream of the power feeder 49 and upstream of the first supply zone SZ1.

[0179] The counter electrode may be disposed in the first supply zone SZ1 on the most upstream side. The counter electrode may further be disposed in at least one of the first exhaust zone EZ1, the second supply zone SZ2, and the second exhaust zone EZ2.

[0180] The film forming apparatus 40A includes a pressing member 45. However, these may be installed arbitrarily. The pressing member 45 is in a roll shape and supports the transport of the metal foil 400. The film forming apparatus 40A further includes a voltage regulator 403 and an AC power source 404. However, these may be installed arbitrarily.

[0181] In another embodiment, the pressing member 45 is the power supplying body. In this case, it is preferable that the third transport roll 473 is not the power supplying body. When a voltage is applied to adjacent members, a potential difference occurs between the members, which may cause the members to corrode.

[0182] [II-iii embodiment] 18 is a side view conceptually showing still another film forming apparatus according to the second and third embodiments. Film forming apparatus 40B has the same configuration as film forming apparatus 40A, except for the arrangement of the power feeders and the number and arrangement of the counter electrodes.

[0183] The current supply body 49 is a supply reel 401 and a recovery reel 402, and is arranged outside the chamber 41. The current supply body 49 may be either the supply reel 401 or the recovery reel 402. Two counter electrodes 48 are arranged in each of the first supply zone SZ1 and the second supply zone SZ2. In each zone, the two counter electrodes 48 are arranged to face each other with the metal foil 400 interposed therebetween.

[0184] [II-iv embodiment] 19 is a side view conceptually showing still another film forming apparatus according to the second and third embodiments. The film forming apparatus 40C has the same configuration as the film forming apparatus 20D shown in FIG. 9, except that the supply reel 401 and the recovery reel 402 also serve as the power supply body 49 and that the film forming apparatus 40C is provided with a plurality of counter electrodes 48.

[0185] That is, the film forming apparatus 40C includes a chamber 41. The metal foil 400 is transported while being folded back multiple times within the chamber 41. The number of times the metal foil is folded back is not particularly limited.

[0186] The chamber 41 includes a first supply port 421 that supplies a first gas G1 to the first supply zone SZ1, a fourth supply port 424 that supplies a fourth gas G4 (second gas G2 or inert gas G3) to the fourth supply zone SZ4, and a fifth supply port 425 that supplies a fifth gas G5 (first gas G1, inert gas G3 or another first gas G1) to the fifth supply zone SZ5.

[0187] In the first supply zone SZ1, a plurality of first transport rolls 471 are arranged. In the fourth supply zone SZ4, a plurality of third transport rolls 473 are arranged. In the fifth supply zone SZ5, a plurality of second transport rolls 472 are arranged.

[0188] The chamber 41 includes a first exhaust port 431 for exhausting the first gas G1 from the first supply zone SZ1, a fourth exhaust port 434 for exhausting the fourth gas G4 from the fourth supply zone SZ4, and a fifth exhaust port 435 for exhausting the fifth gas G5 from the fifth supply zone SZ5.

[0189] The power supply body 49 is a supply reel 401 and a return reel 402, and is disposed outside the chamber 41. The power supply body 49 may be either the supply reel 401 or the return reel 402. At least one of the first transport roll 471, the second transport roll 472, and the third transport roll 473 may be a power supply body.

[0190] Two counter electrodes 48 are disposed in each of the first supply zone SZ1 and the fourth supply zone SZ4. In each zone, the two counter electrodes 48 are disposed so as to face each other with the metal foil 400 interposed therebetween.

[0191] [II-v embodiment] 20 is a side view conceptually showing still another film forming apparatus according to the second and third embodiments. A film forming apparatus 40D has the same configuration as the film forming apparatus 40C shown in FIG.

[0192] All three counter electrodes 48 are long and are arranged such that the longitudinal direction runs from the supply reel 401 to the recovery reel 402 in each supply zone. The counter electrodes 48 are formed with a plurality of slits (not shown) through which the metal foil can pass. The inner walls of the slits function as counter electrodes. When the metal foil passes through the slits, a potential difference is generated between the inner walls and the metal foil. It is sufficient that the counter electrode 48 is arranged in any one of the supply zones.

[0193] There is no particular limitation on the size of the counter electrode 48. In consideration of the degree of freedom in device design and the flow of gas, it is desirable that the counter electrode 48 be large enough not to divide the chamber 41 into a plurality of chambers. The size of the counter electrode 48 is, for example, less than 80% of the area of ​​the bottom of the film forming apparatus 40D.

[0194] [II-vi embodiment] Fig. 21 is a side view conceptually showing still another film forming apparatus according to the second and third embodiments. The film forming apparatus 40E has a similar configuration to the film forming apparatus 40C shown in Fig. 19, except that the chamber 41 also serves as the counter electrode 48. The inner wall of the chamber 41 is conductive. Any point on the inner wall is used as a contact point to generate a potential difference between the metal foil 400.

[0195] IV. Fourth Aspect In this embodiment, the metal foil is heated and a voltage is applied to the metal foil in the presence of at least one of the first gas and the second gas, thereby efficiently forming a uniform dielectric layer.

[0196] [Film forming method] The film forming method according to the fourth embodiment includes a heating step of heating a metal foil, and an application step of applying a voltage to the metal foil in the presence of at least one of a first gas and a second gas. Fig. 22 is a flowchart showing the film forming method according to the fourth embodiment.

[0197] The heating step and the voltage application step are performed in the same manner as in the film forming method according to the first, second and third aspects. The first contact step may be performed while heating the metal foil to which the voltage is applied. The second contact step may be performed while heating the metal foil to which the voltage is applied. The metal foil may be heated by heat generated by the power supply.

[0198] [Electrode foil manufacturing method] The method for producing an electrode foil according to the fourth embodiment includes a heating step of heating a metal foil and an application step of applying a voltage to the metal foil in the presence of at least one of a first gas and a second gas. Fig. 23 is a flow chart showing the method for producing an electrode foil according to the fourth embodiment. The heating step and the application step are performed in the same manner as in the film forming methods according to the first, second and third embodiments.

[0199] [Film forming equipment] The film forming apparatus according to the fourth aspect is provided with a heating element disposed in a chamber, which contacts a portion of a metal foil as a film forming target to heat the metal foil, a power supply body contacting a portion of the metal foil, and a counter electrode for generating a voltage difference between the metal foil and the power supply body. The first gas and the second gas are supplied so as to contact both main surfaces of the metal foil.

[0200] The film production apparatus according to the fourth embodiment includes a chamber, a pressure control unit, a supply port, and an exhaust port similar to those of the film production apparatus according to the first to third embodiments. The film production apparatus according to the fourth embodiment further includes a heating element similar to those of the film production apparatus according to the first embodiment, and a power supply and a counter electrode similar to those of the film production apparatus according to the second and third embodiments. The film production apparatus according to the fourth embodiment may include a support, a pressing member, etc., in the film production apparatus according to the first to third embodiments.

[0201] [IVth embodiment] FIG. 24 is a side view conceptually showing an example of a film forming apparatus according to the fourth embodiment. The film forming apparatus 50 has the same configuration as the film forming apparatus 20A shown in FIG. 6, except that it has a supply reel 501 also serving as a power feeder 59 and a counter electrode 58 similar to those of the film forming apparatus 40B shown in FIG.

[0202] That is, the film forming apparatus 50 includes a chamber 51. The chamber 51 includes a first supply zone SZ1 to which a first gas G1 is supplied, a second supply zone SZ2 to which a second gas G2 is supplied, a first exhaust zone EZ1 to purge the first gas G1, and a second exhaust zone EZ2 to purge the second gas G2. The zones are arranged in this order so as to separate the chamber 51 in a direction intersecting the transport direction. In each zone, a first supply port 521, a second supply port 522, a third supply port 523, a first exhaust port 531, and a second exhaust port 532 are appropriately provided. Purging from each exhaust port is appropriately performed. The exhaust port to be used may be determined as necessary.

[0203] The pressure in chamber 51 is controlled by pressure control unit 56 to create a reduced pressure atmosphere. Pressure control unit 56 may appropriately control the pressure in each zone. Metal foil 500 is wound around supply reel 501 that is driven to rotate by a motor, and is supplied to the upstream of chamber 51 while being unwound from supply reel 501. After processing, metal foil 500 is collected by collection reel 502. Supply reel 501 and collection reel 502 are current feeder 59. Counter electrode 58 is disposed downstream of current feeder 59 and upstream of first supply zone SZ1.

[0204] The counter electrode may be disposed in the first supply zone SZ1 on the most upstream side. The counter electrode may further be disposed in at least one of the first exhaust zone EZ1, the second supply zone SZ2, and the second exhaust zone EZ2.

[0205] A stage 541 that supports the metal foil 500 being transported is disposed on the upstream side of the chamber 51. The stage 541 is a heating element 60. A pressing member 55 for pressing the metal foil 500 toward the stage 541 is disposed at a position corresponding to the stage 541. The pressing member 55 is also a heating element 60. The pressing member 55 is in a roll shape and supports the transportation of the metal foil 500.

[0206] The film forming apparatus 50 further includes a voltage regulator 503 and an AC power source 504. However, these are installed optionally. [Industrial Applicability]

[0207] The electrode foil produced by the method according to the present invention can be used in electrolytic capacitors for various applications to improve the capacitance and voltage resistance. [Explanation of symbols]

[0208] 10A, 10B: Film forming equipment 11: Chamber 121: 1st supply port 122:Second supply port 13: Exhaust port 14: Stage 15: Clamping member 16: Pressure control section 19: Heating element 100: Metal foil

[0209] 20A, 20B, 20C, 20D: Film forming equipment 21: Chamber 221: 1st supply port 222:Second supply port 223: 3rd supply port 23: Exhaust port 231: First exhaust port 232: Second exhaust port 241: Stage 243: Positioning member 25: Clamping member 26: Pressure control section 27: Transport roll 271: First transport roll 272: Second transport roll 273: Third transport roll 28: Conveyor belt 29: Heating element 201: Supply reel 202: Recovery reel 200: Metal foil 200a: Through hole

[0210] 30: Film forming equipment 31: Chamber 321: 1st supply port 322:Second supply port 33: Exhaust port 34: Stage 35: Clamping member 36: Pressure control section 38: Opposite 39: Power feeder 303: Voltage regulator 304: AC power supply 300: Metal foil

[0211] 40A, 40B, 40C, 40D, 40E: Film forming equipment 41: Chamber 421: 1st supply port 422:Second supply port 423: 3rd supply port 424: 4th supply port 425: 5th supply port 431: First exhaust port 432: Second exhaust port 434: 4th exhaust port 435: 5th exhaust port 45: Clamping member 46: Pressure control section 471: First transport roll 472: Second transport roll 473: 3rd transport roll 48: Opposite 49: Power feeder 401: Supply reel 402: Recovery reel 403: Voltage regulator 404: AC power supply 400: Metal foil

[0212] 50: Film forming equipment 51: Chamber 521: 1st supply port 522:Second supply port 523: 3rd supply port 531: First exhaust port 532: Second exhaust port 541: Stage 55: Clamping member 56: Pressure control section 58: Opposite 59: Power feeder 60: Heating element 501: Supply reel 502: Recovery reel 503: Voltage regulator 504: AC power supply 500: Metal foil

Claims

1. A heating step of heating a portion of a metal foil containing a first metal by contacting the metal foil with one or more heating elements; a first contacting step of contacting both sides of the metal foil with a first gas containing a second metal while the metal foil is partially supported; a second contacting step of contacting both surfaces of the metal foil with a second gas containing an oxidizing agent while a portion of the metal foil is supported.

2. The film forming method according to claim 1 , wherein the heating step is performed while pressing the metal foil against the heating element with a pressing member disposed at a position corresponding to the heating element.

3. The film forming method according to claim 1 or 2, wherein in the first contact step, a portion of the metal foil is supported by the heating element.

4. The film forming method according to any one of claims 1 to 3, wherein in the second contact step, a portion of the metal foil is supported by a heating element.

5. The film forming method according to any one of claims 1 to 4, wherein the heating element is a transport roll.

6. The film forming method according to any one of claims 1 to 5, wherein in the heating step, the metal foil is brought into contact with two or more of the heating elements.

7. The film forming method according to any one of claims 1 to 6, wherein the heating step and the first contacting step are carried out in the space of the same chamber.

8. The film forming method according to any one of claims 1 to 7, further comprising a surface modification step of modifying a surface of the metal foil prior to the first contact step.

9. At least one chamber; a pressure control unit that controls the pressure in the chamber to a reduced pressure atmosphere; a first supply port for supplying a first gas containing a second metal to the chamber; a second supply port for supplying a second gas including an oxidant to the chamber; a first exhaust port for exhausting the first gas from the chamber; a second exhaust port for exhausting the second gas from the chamber; one or more heating elements that are disposed in the chamber and contact a portion of the metal foil that is the film-forming target to heat the metal foil; The first gas and the second gas are supplied so as to contact both main surfaces of the metal foil.

10. The film forming apparatus according to claim 9 , further comprising a pressing member disposed at a position corresponding to the heating element for pressing the metal foil against the heating element.

11. The film forming apparatus according to claim 9 or 10, wherein the heating element is a transport roll.

12. The film forming apparatus according to any one of claims 9 to 11, comprising two or more of the heating elements.

13. A preparation step of preparing a metal foil including a first metal; A roughening step of roughening both main surfaces of the metal foil; a heating step of contacting a portion of the roughened metal foil with one or more heating elements to heat the metal foil; a first contacting step of contacting both sides of the metal foil with a first gas containing a second metal while the metal foil is partially supported; a second contacting step of contacting both surfaces of the metal foil with a second gas containing an oxidant while a portion of the metal foil is supported to form a dielectric layer.

14. The method for producing an electrode foil according to claim 13 , wherein the heating step is performed while pressing the metal foil against the heating element with a pressing member disposed at a position corresponding to the heating element.

15. The method for producing an electrode foil according to claim 13 or 14, wherein in the first contact step, a portion of the metal foil is supported by the heating element.

16. The method for producing an electrode foil according to any one of claims 13 to 15, wherein in the second contact step, a portion of the metal foil is supported by a heating element.

17. The method for producing an electrode foil according to any one of claims 13 to 16, wherein the heating element is a transport roll.

18. The method for producing an electrode foil according to any one of claims 13 to 17, wherein in the heating step, the metal foil is brought into contact with two or more of the heating elements.

19. a first contacting step of contacting both sides of a metal foil containing a first metal with a first gas containing a second metal; a second contacting step of contacting both surfaces of the metal foil with a second gas containing an oxidizing agent; A method for forming a layer containing a metal oxide, comprising: a first application step of contacting a portion of the metal foil with one or more first current collectors and applying a voltage to the metal foil in the presence of the first gas.

20. The film forming method according to claim 19 , wherein in the first contact step, a portion of the metal foil is supported by the first current collector.

21. The film forming method according to claim 19 or 20, wherein the first current supply body is a transport roll.

22. The film forming method according to any one of claims 19 to 21, wherein in the first application step, the metal foil is brought into contact with two or more of the first power supply elements.

23. The film forming method according to any one of claims 19 to 22, further comprising a second application step of contacting a portion of the metal foil with one or more second current collectors and applying a voltage to the metal foil in the presence of the second gas.

24. The film forming method according to claim 23 , wherein in the second contact step, a portion of the metal foil is supported by the second current collector.

25. The film forming method according to claim 23 or 24, wherein the second power supply body is a transport roll.

26. The film forming method according to any one of claims 23 to 25, wherein in the second application step, the metal foil is brought into contact with two or more of the second power supply elements.

27. The film forming method according to any one of claims 19 to 26, wherein the metal foil has a roughened surface.

28. The film forming method according to any one of claims 19 to 27, further comprising a surface modification step of modifying a surface of the metal foil prior to the first contact step of applying.

29. A preparation step of preparing a metal foil including a first metal; A roughening step of roughening both main surfaces of the metal foil; a first contacting step of contacting both surfaces of the roughened metal foil with a first gas containing a second metal; a second contacting step of contacting both surfaces of the metal foil with a second gas containing an oxidizing agent; A method for manufacturing an electrode foil, comprising: a first application step of contacting a portion of the metal foil with one or more first current collectors and applying a voltage to the metal foil in the presence of the first gas.

30. 30. The method for producing an electrode foil according to claim 29, wherein in the first contact step, a portion of the metal foil is supported by the first current supply body.

31. The method for producing an electrode foil according to claim 29 or 30, wherein the first current supply body is a transport roll.

32. The method for manufacturing an electrode foil according to any one of claims 29 to 31, wherein in the first application step, the metal foil is brought into contact with two or more of the first power supply elements.

33. The method for producing an electrode foil according to any one of claims 29 to 32, wherein the first application step and the first contact step are carried out in the same chamber space.

34. The method for producing an electrode foil according to any one of claims 29 to 33, further comprising a second applying step of contacting a portion of the metal foil with one or more second current collectors and applying a voltage to the metal foil in the presence of the second gas.

35. The method for producing an electrode foil according to claim 34 , wherein in the second contact step, a portion of the metal foil is supported by the second current collector.

36. The method for producing an electrode foil according to claim 34 or 35, wherein the second current supply body is a transport roll.

37. The method for manufacturing an electrode foil according to any one of claims 34 to 36, wherein in the second application step, the metal foil is brought into contact with two or more of the second power supply elements.

38. The method for producing an electrode foil according to any one of claims 34 to 37, wherein the second application step and the second contact step are carried out within the space of the same chamber.

39. The method for producing an electrode foil according to any one of claims 29 to 38, further comprising a surface modification step of modifying a surface of the metal foil prior to the first contact step.

40. a first contacting step of contacting both sides of a metal foil containing a first metal with a first gas containing a second metal; a second contacting step of contacting both surfaces of the metal foil with a second gas containing an oxidizing agent; a voltage application step of contacting a portion of the metal foil with one or more current collectors and applying a voltage to the metal foil in the presence of the second gas.

41. The film forming method according to claim 40 , wherein in the second contact step, a portion of the metal foil is supported by the current collector.

42. The film forming method according to claim 40 or 41, wherein the power supply body is a transport roll.

43. The film forming method according to any one of claims 40 to 42, wherein the metal foil has a roughened surface.

44. The film forming method according to any one of claims 40 to 43, wherein in the application step, the metal foil is brought into contact with two or more of the power feeders.

45. The film forming method according to any one of claims 40 to 44, further comprising a surface modification step of modifying a surface of the metal foil prior to the first contact step.

46. A preparation step of preparing a metal foil including a first metal; A roughening step of roughening both main surfaces of the metal foil; a first contacting step of contacting both surfaces of the roughened metal foil with a first gas containing a second metal; a second contacting step of contacting both surfaces of the metal foil with a second gas containing an oxidizing agent; A method for manufacturing an electrode foil, comprising: a second application step of contacting a portion of the metal foil with one or more second current collectors and applying a voltage to the metal foil in the presence of the second gas.

47. 47. The method for producing an electrode foil according to claim 46, wherein in the second contact step, a portion of the metal foil is supported by the power supply body.

48. The method for producing an electrode foil according to claim 46 or 47, wherein the second current supply body is a transport roll.

49. The method for manufacturing an electrode foil according to any one of claims 46 to 48, wherein in the second application step, the metal foil is brought into contact with two or more of the second power supply elements.

50. The method for producing an electrode foil according to any one of claims 46 to 49, further comprising a surface modification step of modifying a surface of the metal foil prior to the first contact step.

51. At least one chamber; a pressure control unit that controls the pressure in the chamber to a reduced pressure atmosphere; a first supply port for supplying a first gas containing a second metal to the chamber; a second supply port for supplying a second gas including an oxidant to the chamber; a first exhaust port for exhausting the first gas from the chamber; a second exhaust port for exhausting the second gas from the chamber; One or more current feeders in contact with a part of the metal foil that is the film-forming target; A counter electrode that generates a voltage difference between the metal foil and the power supply body, The first gas and the second gas are supplied so as to contact both main surfaces of the metal foil.

52. The film forming apparatus according to claim 51 , wherein the power supply body is a transport roll.

53. 53. The film forming apparatus according to claim 51 or 52, comprising two or more of the power feeders.

54. A heating step of heating a portion of a metal foil containing a first metal by contacting the metal foil with one or more heating elements; a first contacting step of contacting both sides of the metal foil with a first gas containing a second metal while the metal foil is partially supported; a second contacting step of contacting both surfaces of the metal foil with a second gas containing an oxidizing agent while the metal foil is partially supported; and an application step of contacting a portion of the metal foil with one or more current collectors and applying a voltage to the metal foil in the presence of at least one of the first gas and the second gas.

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