Capacitor, circuit, circuit board, device, member for capacitor, and method for manufacturing capacitor

Abstract

A capacitor is provided with a porous body including a plurality of pores, and a conductive body. The porous body includes a conductive base material, a first dielectric layer disposed on the base material, and a second dielectric layer disposed on the base material. The conductor is disposed on the first dielectric layer and the second dielectric layer. The first dielectric layer is disposed in the porous body in a first region including a boundary between the porous body and an exterior of the porous body. In the porous body, the second dielectric layer is disposed in a second region that is located further inward than the first region than the porous body.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a capacitor, a circuit, a circuit substrate, a device, a member for a capacitor, and a manufacturing method of a capacitor. BACKGROUND

[0002] Conventionally, a capacitor provided with a dielectric layer formed by a vapor phase method such as an atomic deposition method is known.

[0003] For example, in Patent Literature 1, an electrolytic capacitor provided with a dielectric film formed on a surface of an anode foil facing a separator is described. The dielectric film is formed by an atomic layer deposition method.

[0004] In Patent Literature 2, an electrolytic capacitor provided with a prescribed electrode and at least one of an electrolyte impregnated in a porous portion of the electrode and a solid electrolyte is described. The porous portion of the electrode is provided with a porous body, a first dielectric layer covering at least a part of the porous body, and a second dielectric layer covering at least a part of the first dielectric layer. The porous body is integrally formed of a first metal with a core material portion. The second dielectric layer is formed by an atomic layer deposition method.

[0005] PRIOR ART DOCUMENTS PATENT LITERATURE Patent Literature 1: Japanese Patent Application Publication No. 2012-43960 Patent Literature 2: International Publication No. 2018 / 180029 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION The present disclosure provides a capacitor that is advantageous from the viewpoint of voltage resistance and high capacitance.

[0007] MEANS FOR SOLVING THE PROBLEMS The capacitor of the present disclosure is provided with a porous body including a plurality of pores and a conductive body.

[0008] The porous body includes a base material having conductivity, a first dielectric layer disposed on the base material, and a second dielectric layer disposed on the base material.

[0009] The conductive body is disposed on the first dielectric layer and the second dielectric layer, the first dielectric layer is disposed at a first site including a boundary between the porous body and an outside of the porous body in the porous body, and the second dielectric layer is disposed at a second site located more inside the porous body than the first site in the porous body.

[0010] EFFECTS OF THE INVENTION According to the present disclosure, a capacitor that is advantageous from the viewpoint of voltage resistance and high capacitance is provided. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 is a sectional view showing one example of a capacitor of the present disclosure.

[0012] Figure 2 is a sectional view of a portion of Figure 1 enclosed by rectangle II.

[0013] Figure 3 is a flowchart showing one example of a manufacturing method of a capacitor of the present disclosure.

[0014] Figure 4 is a sectional view showing another example of a capacitor of the present disclosure.

[0015] Figure 5 is a sectional view showing still another example of a capacitor of the present disclosure.

[0016] Figure 6 is a sectional view showing still another example of a capacitor of the present disclosure.

[0017] Figure 7 is a sectional view of a portion of Figure 6 enclosed by rectangle VII.

[0018] Figure 8A is a diagram schematically showing one example of a circuit of the present disclosure.

[0019] Figure 8B is a diagram schematically showing one example of a circuit substrate of the present disclosure.

[0020] Figure 8C is a diagram schematically showing one example of an apparatus of the present disclosure. DETAILED DESCRIPTION

[0021] (Insight that is the basis of the present disclosure) It is considered to obtain a capacitor by forming a dielectric layer on a base material having porosity and conductivity. It was found from the research of the present inventor that in a case where a dielectric layer is formed using a gas phase method such as an atomic deposition method in a manufacturing method of an electrolytic capacitor as described in Patent Literature 1, it is difficult to form a dielectric layer on a base material at a portion inside a porous body as a base material. In the manufacturing of a capacitor, an electrically conductive body can be disposed also at a portion inside such a porous body, and therefore it is considered that it is difficult to ensure the withstand voltage of a capacitor only by forming a dielectric layer using a gas phase method.

[0022] As described above, the electrolytic capacitor described in Patent Literature 2 is provided with a first dielectric layer that covers at least a part of the porous body and a second dielectric layer that covers at least a part of the first dielectric layer. The electrostatic capacitance of the capacitor is inversely proportional to the thickness of the dielectric layer. Therefore, the matter that the second dielectric layer is formed in a manner of covering the first dielectric layer as in the electrolytic capacitor described in Patent Literature 2 is hardly said to be advantageous in improving the capacitance of the capacitor. In addition, there is also considered the possibility that the reduction in the withstand voltage accompanied by the formation of a defect level at the interface of the first dielectric layer and the second dielectric layer, and the peeling of the dielectric layer caused by the internal stress due to the difference in thermal expansion between the first dielectric layer and the second dielectric layer.

[0023] In view of such circumstances, the present inventors have repeatedly conducted intensive studies on the constitution of a capacitor that is provided with a porous body including a substrate having conductivity and is advantageous from the viewpoints of the withstand voltage and the high capacitance. As a result, the present inventors have newly found that the capacitor can have a constitution that is advantageous from the viewpoints of the withstand voltage and the high capacitance by adjustment of the dielectric layer formed on the substrate at different parts of the porous body, and have conceived the capacitor of the present disclosure.

[0024] (Embodiment) Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiment.

[0025] Figure 1 is a cross-sectional view showing one example of the capacitor of the present disclosure. As Figure 1As shown, the capacitor 1a includes a base material 10, a first dielectric layer 21, a second dielectric layer 22, and a conductive body 30. The base material 10 has conductivity. The first dielectric layer 21 and the second dielectric layer 22 are respectively arranged on the base material 10. The first dielectric layer 21 and the second dielectric layer 22 are respectively in contact with the base material 10. Further, sometimes a natural oxide film is formed on a base material having conductivity. The first dielectric layer 21 and the second dielectric layer 22 are respectively different dielectric layers from a layer composed only of the natural oxide film. The base material 10, the first dielectric layer 21, and the second dielectric layer 22 constitute a porous body 15. The porous body 15 has a hole 15p extending inward. In the porous body 15, the first dielectric layer 21 is arranged at a first site 15a. The first site 15a is a site including a boundary 16 between the porous body 15 and the outside. In the porous body 15, the second dielectric layer 22 is arranged at a second site 15b. The second site 15b is a site located more inward than the first site 15a in the porous body 15. According to such a structure, in the first site 15a and the second site 15b, the first dielectric layer 21 and the second dielectric layer 22 are respectively arranged on the base material 10, and thus the capacitor 1a easily has desired withstand voltage. Further, since both the first dielectric layer 21 and the second dielectric layer 22 are arranged on the base material 10, the thickness of the dielectric layer is difficult to be large, and the capacitor 1a easily has high capacitance.

[0026] The first dielectric layer 21 is not limited to a particular dielectric layer. The first dielectric layer 21, for example, includes an evaporation film. In this case, the relative dielectric constant of the material constituting the first dielectric layer 21 easily becomes high, and the capacitor 1a more easily has high capacitance. In the present specification, evaporation can include physical evaporation and chemical evaporation as described in Japanese Industrial Standard JIS H0211-1992. The first dielectric layer 21 can also include a natural oxide film as a site in contact with the base material 10. The evaporation film can also be a film formed by a vapor phase method. The vapor phase method is not limited to a particular vapor phase method. Examples of the vapor phase method are atomic layer deposition (ALD), chemical vapor deposition (CVD), and chemical vapor deposition by mist (Mist CVD).

[0027] The material of the first dielectric layer 21 is not limited to a particular material. The first dielectric layer 21, for example, includes a metal compound. The metal compound, for example, includes at least one selected from a metal oxide, a metal nitride, and a metal oxynitride. Further, the metal compound includes at least one selected from hafnium, zirconium, aluminum, tantalum, titanium, silicon, and zinc. In this case, the capacitor 1a more easily has desired withstand voltage, and the capacitor 1a more easily has high capacitance.

[0028] Examples of the metal oxide included in the first dielectric layer 21 are HfO2, ZrO2, Hf 1-x Zr xO2, Al2O3, Ta2O5, TiO2, SiO2, and ZnO. x satisfies the condition of 0 < x < 1. Examples of the metal nitride contained in the first dielectric layer 21 are HfN, ZrN, Hf 1-x Zr x N, AlN, and SiN. Examples of the metal oxynitride contained in the first dielectric layer 21 are HfON, ZrON, HfZrON, AlON, and SiON.

[0029] The first dielectric layer 21 can further contain at least one selected from yttrium, cerium, and gallium. In this case, the first dielectric layer 21 is more likely to have a higher relative dielectric constant.

[0030] The thickness of the first dielectric layer 21 is not limited to a particular value. The thickness is, for example, 5 nm or more. Thereby, the leakage current is suppressed, and the capacitor 1a is more likely to have a desired withstand voltage. The thickness of the first dielectric layer 21 is, for example, 500 nm or less. Thereby, the capacitor 1a is more likely to have a high capacitance. The thickness of the first dielectric layer 21 can be 10 nm or more, and can be 400 nm or less, 300 nm or less, 200 nm or less, 100 nm or less, 50 nm or less, or 20 nm or less.

[0031] The second dielectric layer 22 is not limited to a particular dielectric layer. The second dielectric layer 22 is, for example, a layer containing a different kind of dielectric from the first dielectric layer 21. The second dielectric layer 22 contains, for example, an anodized film. In this case, even if the second portion 15b is away from the boundary 16, the second dielectric layer 22 can be formed on the substrate 10. Further, the second dielectric layer 22 is more likely to be uniformly formed at a desired thickness at the second portion 15b. Therefore, the capacitor 1a is more likely to have a desired withstand voltage. The second dielectric layer 22 can also contain an oxide film other than a natural oxide film or an anodized film. For example, the second dielectric layer 22 can also contain an oxide film formed by heat treatment in an oxidizing atmosphere.

[0032] The material of the second dielectric layer 22 is not limited to a particular material. The second dielectric layer 22 contains, for example, an oxide. The oxide contains, for example, at least one selected from hafnium, zirconium, aluminum, tantalum, titanium, silicon, and niobium. In this case, the capacitor 1a is more likely to have a desired withstand voltage, and the capacitor 1a is more likely to have a high capacitance.

[0033] Examples of the oxide contained in the second dielectric layer 22 are HfO2, ZrO2, Hf 1-x Zr xO2, Al2O3, Ta2O5, TiO2, SiO2, and Nb2O5. x satisfies the condition of 0 < x < 1. The second dielectric layer 22 preferably contains at least one selected from Al2O3and Ta2O5. In this case, the capacitor la is more likely to have a desired withstand voltage.

[0034] The thickness of the second dielectric layer 22 is not limited to a particular value. The thickness is, for example, 5 nm or more. Thereby, the leakage current is suppressed, and the capacitor la is more likely to have a desired withstand voltage. The thickness of the second dielectric layer 22 is, for example, 500 nm or less. Thereby, the capacitor la is more likely to have a high capacitance. The thickness of the second dielectric layer 22 can be 10 nm or more, and can be 400 nm or less, 300 nm or less, 200 nm or less, 100 nm or less, 50 nm or less, or 20 nm or less.

[0035] Figure 2 is Figure 1 a cross-sectional view of a portion enclosed by the rectangle II. As Figure 2 indicated, at the boundary between the first portion 15a and the second portion 15b, the first dielectric layer 21 is in contact with the second dielectric layer 22. For example, in a case where the first dielectric layer 21 contains an evaporation film and the second dielectric layer 22 contains an anodized film, the end portion of the first dielectric layer 21 can also coincide with the end portion of the second dielectric layer 22. Evaporation is a film formation by attachment of a solid component from a gas phase component to a substrate. On the other hand, anodization is a formation of an oxide film by oxidation of a part of the surface of an anode. Depending on the difference in the mechanism of film formation, as Figure 2 indicated, the end portion of the first dielectric layer 21 containing an evaporation film can be disposed on the end portion of the second dielectric layer 22 containing an anodized film.

[0036] The relationship between the relative dielectric constant ε 21 of the first dielectric layer 21 and the relative dielectric constant ε 22 of the second dielectric layer 22 is not limited to a particular relationship. For example, the relative dielectric constant ε 21 and the relative dielectric constant ε 22 are different from each other. For example, the relative dielectric constant ε 21 is higher than the relative dielectric constant ε 22 . In this case, the capacitor la is more likely to have a high capacitance than in a case where the second dielectric layer 22 is disposed on the substrate 10 in the first portion 15a and the second portion 15b of the porous body 15.

[0037] As Figure 1 indicated, the substrate 10 has, for example, a porous portion 11 and a core portion 12. The porous body 15 contains the porous portion 11. The core portion 12 is a non-porous portion.

[0038] The material of the base material 10 is not limited to a particular material. The base material 10 includes, for example, a valve metal. Examples of the valve metal are Al, Ta, Ti, Hf, Zr, Si, and Nb. In this case, the second dielectric layer 22 is easily formed by an anodization method or the like.

[0039] The valve metal included in the base material 10 can also be aluminum. In this case, the porous portion 11 can be formed, for example, by electric field etching of an aluminum foil.

[0040] The base material 10 can also be a metal sintered body. In this case, the base material 10 easily has a desired porosity, and the capacitor la more easily has a high capacitance.

[0041] The metal included in the metal sintered body is not limited to a particular metal. The metal sintered body includes, for example, tantalum.

[0042] The pore diameter of the pores in the porous portion 11 is not limited to a particular value. The pore diameter is, for example, 10 nm or more. Thereby, the specific surface area of the porous portion 11 easily becomes large, and the capacitor la more easily has a high capacitance. The pore diameter is, for example, 1 μm or less. Thereby, the formation of the first dielectric layer 21 becomes easy, and the first portion and the second portion easily are arranged in a desired state, and the capacitor la more easily has a high capacitance. The pore diameter of the pores in the porous portion 11 can be 20 nm or more, 30 nm or more, 40 nm or more, or 50 nm or more, and can be 900 nm or less, 800 nm or less, 700 nm or less, 600 nm or less, or 500 nm or less.

[0043] The size (depth) Dl of the first portion 15a in the direction perpendicular to the boundary 16 and the size (depth) D2 of the second portion 15b in the direction perpendicular to the boundary 16 are not limited to a particular relationship. The size Dl can also be equal to or greater than the size D2. In this case, the volume of the first portion 15a in the volume of the porous body 15 easily becomes large, and thus the relative dielectric constant εr of the first portion 15a 21 is high, and the capacitor la more easily has a high capacitance. 22 is high, and the capacitor la more easily has a high capacitance.

[0044] The size Dl can also be smaller than the size D2. In this case, the volume of the first portion 15a in the volume of the porous body 15 easily becomes small. Thus, for example, in the case where the first dielectric layer 21 is formed by evaporation and the second dielectric layer 22 is formed by an anodization method or heat treatment in an oxidizing atmosphere, the manufacturing time of the capacitor la easily is shortened. This is because the film formation time by the anodization method or the heat treatment in the oxidizing atmosphere is shorter than the film formation time by the evaporation.

[0045] The electrically conductive body 30 is only required to have electrical conductivity, and is not limited to a specific electrically conductive body. The electrically conductive body 30, for example, contains at least one selected from the group consisting of an electrically conductive polymer, an electrolytic solution, and manganese oxide. In this case, the capacitor la easily has high reliability. Examples of the electrically conductive polymer are polyaniline and polypyrrole.

[0046] The electrically conductive body 30 preferably contains at least one selected from the group consisting of an electrolytic solution and an electrically conductive polymer. In this case, the electrically conductive body 30 easily functions to repair itself, and the capacitor la easily has high reliability.

[0047] Figure 3 is a flowchart showing one example of a method of manufacturing a capacitor according to the present disclosure. The capacitor la, for example, has a substrate 10 having electrical conductivity and porosity, a first dielectric layer 21, and a second dielectric layer 22. The method of manufacturing the capacitor la includes disposing an electrically conductive body 30 in a hole 15p of a porous body 15 having the hole 15p extending inward. The electrically conductive body 30 is disposed in the hole 15p in contact with the first dielectric layer 21 and the second dielectric layer 22. The first dielectric layer 21 is formed on a first site 15a of the substrate 10 by a vapor phase method. The second dielectric layer 22 is formed on a second site 15b of the substrate 10 by anodization or thermal oxidation. The first site 15a is a site in the porous body 15 that includes a boundary 16 between the porous body 15 and the outside of the porous body 15. The second site 15b is a site in the porous body 15 that is located more inward of the porous body 15 than the first site 15a.

[0048] As shown in Figure 3 , in step Sll, the first dielectric layer 21 is formed on the first site 15a of the substrate 10 by a vapor phase method. The vapor phase method is not limited to a specific vapor phase method. Examples of the vapor phase method are atomic layer deposition (ALD), chemical vapor deposition (CVD), and a chemical vapor phase method such as mist CVD. In this case, a desired site of the substrate 10 is easily coated with the first dielectric layer 21. The vapor phase method is preferably ALD. In this case, a desired site of the substrate 10 is easily coated with the first dielectric layer 21, and the first dielectric layer 21 is easily formed uniformly. The vapor phase method can also be a physical vapor deposition such as vacuum evaporation.

[0049] Next, in step S12, the second dielectric layer 22 is formed on the second site 15b of the substrate 10 by anodization or thermal oxidation. In this manner, the capacitor member having the substrate 10, the first dielectric layer 21, and the second dielectric layer 22 is obtained.

[0050] Next, in step S13, the electrically conductive body 30 is disposed in the hole 15p of the porous body 15 of the capacitor member. For example, in the case where the electrically conductive body 30 contains an electrically conductive polymer, the electrically conductive polymer can be obtained by performing electrolytic polymerization in a state where a precursor of the electrically conductive body 30 is supplied to the hole 15p. For example, the operation is performed in this way to obtain the capacitor la.

[0051] Figure 4 is a cross-sectional view showing another example of the capacitor of the present disclosure. Figure 4 The capacitor lb shown is constituted similarly to the capacitor la except for the portions specifically described. The same reference numerals are assigned to the constituent elements of the capacitor lb that are the same as or correspond to the constituent elements of the capacitor la, and detailed description is omitted. The description of the capacitor la is also applicable to the capacitor lb as long as it is not technically contradictory.

[0052] As shown in Figure 4 The substrate 10 has, for example, two porous portions 11 and a core portion 12. The core portion 12 is disposed between the two porous portions 11. Alternatively, the substrate 10 can have a cylindrical surface that constitutes the boundary 16, and the porous portions 11 can be formed on the cylindrical surface, and the core portion 12 can be surrounded by the porous portions 11. According to such a structure, the specific surface area of the substrate 10 in contact with the dielectric layer is likely to be large, and the capacitor la is more likely to have a high capacitance. The size (depth) D1 of the first site 15a in the direction perpendicular to the boundary 16 can be the same or different between the two porous portions 11. The size (depth) D2 of the second site 15b in the direction perpendicular to the boundary 16 can be the same or different between the two porous portions 11.

[0053] Figure 5 is a cross-sectional view showing another example of the capacitor of the present disclosure. Figure 5 The capacitor lc shown is constituted similarly to the capacitor la except for the portions specifically described. The same reference numerals are assigned to the constituent elements of the capacitor lc that are the same as or correspond to the constituent elements of the capacitor la, and detailed description is omitted. The description of the capacitor la is also applicable to the capacitor lc as long as it is not technically contradictory.

[0054] As shown in Figure 5 In the porous body 15, the hole 15p contains a through-hole. According to such a structure, the specific surface area of the substrate 10 in contact with the dielectric layer is likely to be large, and the capacitor la is more likely to have a high capacitance.

[0055] Figure 6 is a cross-sectional view showing another example of the capacitor of the present disclosure. Figure 6The capacitor 1d shown is constructed in the same manner as capacitor 1a, except where specifically described. The same reference numerals are used for the constituent elements of capacitor 1d that are identical or corresponding to those of capacitor 1a, and detailed descriptions are omitted. The description of capacitor 1a also applies to capacitor 1d, provided it is not technically contradictory.

[0056] like Figure 6 As shown, capacitor 1d further includes a third dielectric layer 23. The third dielectric layer 23 is disposed on substrate 10. In porous body 15, the third dielectric layer 23 is disposed at first location 15a. The third dielectric layer 23 is, for example, surrounded by a first dielectric layer 21. The third dielectric layer 23 includes, for example, an anodic oxide film. The third dielectric layer 23 may also include an oxide film formed by heat treatment under an oxidizing atmosphere. The third dielectric layer 23 is a dielectric layer different from a layer consisting only of a natural oxide film.

[0057] As described above, for example, when the first dielectric layer 21 is formed by the vapor phase method, it is assumed that, according to the conditions of the vapor phase method, a portion of the first portion 15a of the substrate 10 will be exposed. However, according to the capacitor manufacturing method described above, an oxide film such as an anodic oxide film can also be formed on the portion of the substrate 10 exposed in the first portion 15a when the first dielectric layer 21 is formed. As a result, a capacitor 1d having a third dielectric layer 23 is obtained. Regarding the material and thickness of the third dielectric layer 23, please refer to the description of the material and thickness of the first dielectric layer 21.

[0058] Figure 7 yes Figure 6 A sectional view of the portion enclosed by rectangle VII. (See example...) Figure 7 As shown, the outer periphery of the third dielectric layer 23 may also overlap with the first dielectric layer 21. For example, the first dielectric layer 21 may be disposed on the outer periphery of the third dielectric layer 23.

[0059] Figure 8A This diagram schematically illustrates an example of a circuit according to the present disclosure. Circuit 3 includes capacitor 1a. Circuit 3 can be an active circuit or a passive circuit. Circuit 3 can be a discharge circuit, a smoothing circuit, a decoupling circuit, or a coupling circuit. Because circuit 3 includes capacitor 1a, circuit 3 readily exhibits the desired performance. For example, noise is easily reduced in circuit 3. Circuit 3 may also include capacitors 1b, 1c, or 1d.

[0060] Figure 8B This is a schematic diagram illustrating an example of a circuit board according to the present disclosure. (See diagram for example.) Figure 8BAs shown, the circuit board 5 is provided with the capacitor la. For example, in the circuit board 5, a circuit 3 including the capacitor la is formed. Since the circuit board 5 is provided with the capacitor la, the circuit board 5 easily exhibits desired performance. The circuit board 5 can be an embedded board, or a mother board. The circuit board 5 can be provided with the capacitors lb, lc, or ld.

[0061] Figure 8C is a diagram schematically showing one example of an apparatus of the present disclosure. As shown, the apparatus 7 includes the capacitor la. The apparatus 7 is provided with, for example, a circuit board 5 including the capacitor la. The apparatus 7 is provided with the capacitor la, and thus the apparatus 7 easily exhibits desired performance. The apparatus 7 can be an electronic apparatus, a communication apparatus, a signal processing device, or a power supply device. The apparatus 7 can be a server, an AC adapter, an accelerator, a liquid crystal display device (LCD), or the like. The apparatus 7 can be a USB charger, a solid state drive (SSD), a PC, a smartphone, a tablet PC, or the like. The apparatus 7 can include the capacitors lb, lc, or ld. Figure 8C

[0062] (Postscript) According to the above description, the following technology is disclosed.

[0063] (Technology 1) A capacitor includes a porous body including a plurality of pores, and a conductive body, the porous body includes a base material having conductivity, a first dielectric layer disposed on the base material, and a second dielectric layer disposed on the base material, the conductive body is disposed on the first dielectric layer and the second dielectric layer, in the porous body, the first dielectric layer is disposed at a first site including a boundary between the porous body and an outside of the porous body, and in the porous body, the second dielectric layer is disposed at a second site located more inside the porous body than the first site.

[0064] (Technology 2) The capacitor according to Technology 1, wherein the first dielectric layer includes an evaporation film.

[0065] (Technology 3) The capacitor according to Technology 1 or 2, wherein the second dielectric layer includes an anodized film.

[0066] (Technology 4) ​The capacitor according to any one of techniques 1 to 3, wherein the first dielectric layer has a higher relative dielectric constant than the second dielectric layer.

[0067] (Technique 5) The capacitor according to any one of techniques 1 to 4, wherein the base material comprises a valve metal.

[0068] (Technique 6) The capacitor according to technique 5, wherein the valve metal is aluminum.

[0069] (Technique 7) The capacitor according to any one of techniques 1 to 6, wherein the base material is a metal sintered body.

[0070] (Technique 8) The capacitor according to technique 7, wherein the metal sintered body comprises tantalum.

[0071] (Technique 9) The capacitor according to any one of techniques 1 to 8, wherein the first dielectric layer comprises a metal compound comprising at least one selected from the group consisting of metal oxides, metal nitrides, and metal oxynitrides, the metal compound comprising at least one selected from the group consisting of hafnium, zirconium, aluminum, tantalum, titanium, silicon, and zinc.

[0072] (Technique 10) The capacitor according to any one of techniques 1 to 9, wherein the second dielectric layer comprises an oxide comprising at least one selected from the group consisting of hafnium, zirconium, aluminum, tantalum, titanium, silicon, and niobium.

[0073] (Technique 11) The capacitor according to any one of techniques 1 to 10, wherein the electric conductor comprises at least one selected from the group consisting of electrically conductive polymers, electrolytic solutions, and manganese oxides.

[0074] (Technique 12) A circuit comprising the capacitor according to any one of techniques 1 to 11.

[0075] (Technique 13) A circuit substrate comprising the capacitor according to any one of techniques 1 to 11.

[0076] (Technique 14) An apparatus comprising the capacitor according to any one of techniques 1 to 11.

[0077] (Technique 15) A capacitor member comprising a porous body comprising a plurality of pores, The porous body includes a substrate having electrical conductivity, a first dielectric layer disposed on the substrate, and a second dielectric layer disposed on the substrate, In the porous body, the first dielectric layer is disposed at a first site including a boundary between the porous body and the outside of the porous body, and in the porous body, the second dielectric layer is disposed at a second site located more inside the porous body than the first site.

[0078] (Technology 16) A method for manufacturing a capacitor includes: preparing the capacitor member described in Technology 15; and disposing an electrically conductive body in the plurality of pores of the porous body so that the electrically conductive body is in contact with the first dielectric layer and the second dielectric layer.

[0079] (Technology 17) The method for manufacturing a capacitor according to Technology 16, wherein in the step of preparing the capacitor member, the first dielectric layer is formed by a vapor phase method, and the second dielectric layer is formed by anodization or thermal oxidation.

[0080] Embodiment Hereinafter, the present disclosure will be described in further detail by embodiments. Note that the following embodiments are illustrative, and the present disclosure is not limited to the following embodiments.

[0081] <Embodiment 1> An Al foil having a thickness of 120 μm was prepared. The Al foil was subjected to an alternating current etching treatment to make the surface porous, thereby obtaining a substrate having a core portion and a porous portion. The porous portion having a thickness of 40 μm was formed on both surfaces of the Al foil by etching. The mode pore diameter of the pore distribution in the porous portion was 100 to 200 nm as measured with a mercury porosimeter.

[0082] A ZrO2 layer was formed using an atomic layer deposition (ALD) device FlexAL manufactured by Oxford Instruments. The film formation conditions of the ALD were adjusted as follows. Thus, the ZrO2 layer was formed on the substrate at the surface and in the vicinity of the surface of the porous portion.

[0083] Temperature: 250°C Precursor: tetra(ethylmethylamino)zirconium (TEMAZ) Oxidizing agent: O2 plasma Pressure: 250 mTorr Number of cycles: 140 cycles A ZrO2layer was formed on the surface of the porous portion and in the vicinity of the surface of the porous portion of the substrate. An Al2O3layer was formed on the substrate in the deep portion of the porous portion by anodizing the substrate. The anodizing was performed by immersing the substrate in a 0.3 mol / L aqueous diammonium adipate solution and applying a voltage of 7 V to the substrate as an anode for 60 minutes. The sample of Example 1 was obtained by performing the operation in this manner.

[0084] <Comparative Example 1> The sample of Comparative Example 1 was obtained by performing the operation in the same manner as in Example 1 except that anodizing was not performed.

[0085] (Observation of cross-sectional structure) A sample for cross-sectional observation was prepared by embedding the samples of Example 1 and Comparative Example 1 in resin. A scanning electron microscope (SEM) JSM7900F manufactured by JEOL Ltd. and a scanning transmission electron microscope (STEM) manufactured by JEOL Ltd. were used to obtain electron microscope photographs of the samples. The electron microscope photographs of the sample prepared from the sample of Example 1 revealed that, in the vicinity of the surface of the porous portion of the sample of Example 1, a ZrO2layer was disposed on the Al substrate and covered the Al substrate well. On the other hand, in the deep portion of the porous portion of the sample of Example 1, an Al2O3layer was disposed on the Al substrate and covered the Al substrate well. The thickness of the ZrO2layer in the vicinity of the surface of the porous portion and the thickness of the Al2O3layer in the deep portion of the porous portion confirmed from the electron microscope photographs of the sample prepared from the sample of Example 1 are shown in Table 1.

[0086] The electron microscope photographs of the sample prepared from the sample of Comparative Example 1 revealed that, in the vicinity of the surface of the porous portion of the sample of Comparative Example 1, a ZrO2layer was disposed on the Al substrate and covered the Al substrate well. On the other hand, in the deep portion of the porous portion of the sample of Comparative Example 1, the thickness of the Al2O3layer on the Al substrate was 1 nm or less, and it was considered that the Al2O3was derived from a natural oxide film. The thickness of the ZrO2layer in the vicinity of the surface of the porous portion and the thickness of the Al2O3layer in the deep portion of the porous portion confirmed from the electron microscope photographs of the sample prepared from the sample of Comparative Example 1 are shown in Table 1. The natural oxide film confirmed in the deep portion of the porous portion of the sample of Comparative Example 1 had a low insulating property and was substantially the same as the state in which Al was exposed. Therefore, it was difficult to form a substantial dielectric layer on the substrate in the deep portion of the porous portion by a vapor phase method such as ALD, and it was difficult to say that the sample of Comparative Example 1 had a structure that was advantageous from the viewpoint of the withstand voltage and the high capacitance of the capacitor.

[0087] On the other hand, it can be understood that the sample of Example 1 has a structure that is advantageous from the viewpoint of the withstand voltage and the high capacitance when a capacitor is formed by filling the pores of the porous portion with an electrically conductive body.

[0088] Table 1

[0089] Industrial applicability The capacitor of the present disclosure can be used, for example, for applications requiring voltage resistance and high capacitance.

[0090] Explanation of reference numerals 1a, 1b, 1c, 1d Capacitor 3 Circuit 5 Circuit substrate 7 Device 10 Base material 11 Porous portion 12 Core portion 15 Porous body 15a First portion 15b Second portion 15p Pore 16 Boundary 21 First dielectric layer 22 Second dielectric layer 23 Third dielectric layer 30 Electrode

Claims

1. A capacitor comprising a porous body including multiple pores and a conductive body, The porous body comprises a conductive substrate, a first dielectric layer disposed on the substrate, and a second dielectric layer disposed on the substrate. The conductor is disposed on the first dielectric layer and the second dielectric layer. In the porous body, the first dielectric layer is disposed at a first portion including the boundary between the porous body and the outside of the porous body, and the second dielectric layer is disposed at a second portion located further inside the porous body than the first portion.

2. The capacitor according to claim 1, wherein, The first dielectric layer comprises a vapor-deposited film.

3. The capacitor according to claim 1, wherein, The second dielectric layer comprises an anodic oxide film.

4. The capacitor according to claim 1, wherein, The relative permittivity of the first dielectric layer is higher than that of the second dielectric layer.

5. The capacitor according to claim 1, wherein, The substrate comprises valve metal.

6. The capacitor according to claim 5, wherein, The valve is made of aluminum.

7. The capacitor according to claim 1, wherein, The substrate is a sintered metal body.

8. The capacitor according to claim 7, wherein, The sintered metal body contains tantalum.

9. The capacitor according to claim 1, wherein, The first dielectric layer comprises a metal compound, the metal compound comprising at least one selected from metal oxides, metal nitrides and metal oxynitrides, and the metal compound comprising at least one selected from hafnium, zirconium, aluminum, tantalum, titanium, silicon and zinc.

10. The capacitor according to claim 1, wherein, The second dielectric layer comprises an oxide, which comprises at least one selected from hafnium, zirconium, aluminum, tantalum, titanium, silicon, and niobium.

11. The capacitor according to claim 1, wherein, The conductor comprises at least one selected from conductive polymers, electrolytes, and manganese oxide.

12. A circuit comprising a capacitor according to any one of claims 1 to 11.

13. A circuit board comprising a capacitor according to any one of claims 1 to 11.

14. An apparatus comprising the capacitor according to any one of claims 1 to 11.

15. A capacitor component comprising a porous body including a plurality of holes. The porous body comprises a conductive substrate, a first dielectric layer disposed on the substrate, and a second dielectric layer disposed on the substrate. In the porous body, the first dielectric layer is disposed at a first portion including the boundary between the porous body and the outside of the porous body, and the second dielectric layer is disposed at a second portion located further inside the porous body than the first portion.

16. A method for manufacturing a capacitor, comprising: Prepare the capacitor component as described in claim 15; and Conductors are disposed in the plurality of holes of the porous body, such that the conductors are in contact with the first dielectric layer and the second dielectric layer.

17. The method of manufacturing a capacitor according to claim 16, wherein, In the step of preparing the capacitor component, the first dielectric layer is formed by vapor phase method, and the second dielectric layer is formed by anodic oxidation or thermal oxidation.

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