JP2010192502A - Capacitor, and method of manufacturing capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that since tantalum used as an anode of a tantalum capacitor serves for high hydrogen absorption, needs to be exposed to an atmosphere during anodic oxidation for forming a dielectric layer on a porous tantalum electrode, and selectively absorbs hydrogen in the atmosphere once the porous tantalum electrode is taken out in the atmosphere, the porous tantalum electrode decreases in strength because of hydrogen brittleness and then the tantalum capacitor is broken even with a weak shock. <P>SOLUTION: The method of manufacturing the capacitor includes heating a sintered pellet 205 (porous tantalum electrode) under a vacuum (for example, approximately 10<SP>-3</SP>Pa) at approximately 400°C to approximately 1,000°C to dehydrogenize the sintered pellet 205. Then the method of manufacturing the capacitor includes oxidizing the sintered pellet 205 without exposing it to the atmosphere to newly form an oxide layer 208A on the sintered pellet 205. The oxide layer 208A has a hydrogen barrier property and prevents the sintered pellet 205 from absorbing hydrogen in the atmosphere even when exposed to the atmosphere. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a capacitor and a method for manufacturing the capacitor.

  Conventionally, capacitors using tantalum pentoxide as a dielectric layer (hereinafter referred to as tantalum capacitors) have been mounted in electronic devices. Since tantalum pentoxide has a high relative dielectric constant of about 27, it can provide a small-sized and large-capacitance capacitor, and is particularly suitable for mobile devices. Tantalum capacitors have better leakage current characteristics, frequency characteristics, and temperature characteristics than aluminum electrolytic capacitors.

  In recent years, capacitors using niobium pentoxide as a dielectric layer (hereinafter referred to as niobium capacitors) have become widespread. Since niobium has about 100 times more reserve than tantalum, it is possible to stabilize the supply of capacitor raw material. In addition, since the relative dielectric constant of niobium pentoxide is about 41, which is about 1.5 times higher than that of tantalum pentoxide, it is possible to form a small-sized and large-capacity capacitor compared to a tantalum capacitor. .

  The tantalum capacitor is formed by using a process of anodizing porous tantalum obtained by sintering tantalum fine particles to form tantalum pentoxide to be a dielectric layer. Here, a natural oxide layer is formed on the porous tantalum before anodic oxidation. The natural oxide layer often contains impurities, has a low quality as a dielectric layer, and contributes to deterioration of electrical characteristics. Further, since hydrogen in the porous tantalum causes hydrogen embrittlement with respect to the base porous tantalum, it is preferable to remove this hydrogen. Patent Document 1 discloses a technique of removing hydrogen by removing a natural oxide layer and then heating under vacuum.

In addition, since niobium capacitors similarly cause hydrogen embrittlement, it is preferable to use a process for removing hydrogen as well. In Patent Document 2, porous niobium used for a niobium capacitor is baked at 1100 to 1400 ° C. in an atmosphere with a furnace internal pressure of 1 × 10 ⁻³ Pa, hydrogen is removed, and then a chemical conversion film is formed. A technique for removing hydrogen is disclosed.

JP 2000-252169 A (paragraphs: 0006, 0009 to 0010) JP 2003-342603 A (paragraphs: 0014 to 0016)

  In both cases of Patent Document 1 and Patent Document 2 described above, a process of forming a dielectric film is performed after heating in a vacuum atmosphere and then charging the solution. When thrown into the solution, porous tantalum and porous niobium are exposed to the atmosphere. Porous tantalum and porous niobium selectively absorb hydrogen, so that they are exposed to the atmosphere, and at the same time, absorb hydrogen in the atmosphere and adsorb about 3 at% of hydrogen, thereby forming a natural oxide layer. Therefore, even if the natural oxide layer is removed or dehydrogenated, hydrogen is adsorbed inside the porous tantalum or porous niobium, and a natural oxide layer is also formed, deteriorating the properties as a dielectric layer. However, there is a problem that hydrogen embrittlement also occurs.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  [Application Example 1] A capacitor according to this application example includes a first electrode made of tantalum, niobium, or a metal containing both tantalum and niobium, a second electrode, and the first electrode and the second electrode. And a dielectric layer made of tantalum oxide, niobium oxide, or an oxide containing both tantalum and niobium, and an electrolyte layer located between the dielectric layer and the second electrode. The hydrogen content in the electrode is 2 at% or less.

  According to this, hydrogen embrittlement of the first electrode made of tantalum, niobium or tantalum and niobium can be suppressed. Tantalum, niobium, or a metal containing both tantalum and niobium has a strong hydrogen absorptivity, and absorbs hydrogen of about 3 at% only by being left in the atmosphere. Metals that have absorbed hydrogen become brittle and weak against mechanical shock. Therefore, by suppressing the hydrogen content in the first electrode containing tantalum, niobium or both tantalum and niobium to 2 at% or less, it becomes possible to enhance the resistance to mechanical impact.

Application Example 2 In the capacitor according to the application example described above, the first electrode has a structure including a gap having a density of 3 g / cm ³ or more and 6 g / cm ³ or less.

According to the application example described above, when the density is 3 g / cm ³ or more, the mechanical strength of the first electrode can be maintained, and the resistance to mechanical impact can be maintained. Further, by suppressing the density to 6 g / cm ³ or less, the equivalent area of the first electrode can be increased, and the power storage amount of the capacitor can be improved (product of breakdown voltage and capacity). In particular, since the hydrogen concentration in the first electrode is reduced, it is possible to provide strength that can withstand mechanical shock even when the amount of voids is increased to ³ g / cm ³ .

  [Application Example 3] The method of manufacturing a capacitor according to this application example is as follows. (1) Tantalum, niobium, or metal particles having an average particle diameter of 0.05 μm or more and 5 μm or less made of tantalum and niobium are used as tantalum, niobium, or tantalum. A step of forming a granular pellet by compressing it in a state of including a part of a lead wire including both niobium and niobium, and (2) sintering the granular pellet and combining the metal particles constituting the granular pellet Modifying the sintered pellet; (3) heating the sintered pellet in a state where the partial pressures of hydrogen and oxygen are lowered to remove hydrogen in the sintered pellet; and (4) the firing A step of introducing an oxygen-containing gas without exposing the sintered pellet to the atmosphere to form an oxide layer; and (5) a step of anodic oxidation by immersing the sintered pellet with the oxide layer formed in a chemical conversion liquid. When, It is characterized by including.

  According to this, as shown in the step (4), an oxide layer is formed without exposing the sintered pellet to the atmosphere. The metal oxide layer containing tantalum, niobium, or both tantalum and niobium has a hydrogen barrier property, so even if it is exposed to the atmosphere after forming the oxide layer, it will not absorb the hydrogen present in the atmosphere. Absent. Further, since the oxide layer functions as a hydrogen barrier layer when anodizing is performed, hydrogen is not absorbed. Therefore, it is possible to provide a method for manufacturing a capacitor that can suppress hydrogen embrittlement. Note that the oxide layer and the layer formed by anodic oxidation function as a dielectric layer together.

  Application Example 4 A method for manufacturing a capacitor according to the application example described above, wherein the atmosphere in the step (3) is a reduced pressure atmosphere.

  According to the application example described above, the heat treatment can be performed in a state where the partial pressure of oxygen or hydrogen is lowered, and the dehydrogenation treatment can be reliably performed.

  Application Example 5 A method for manufacturing a capacitor according to the application example described above, wherein the atmosphere in the step (3) is a normal pressure or a reduced pressure rare gas atmosphere.

  According to the application example described above, the degassing derived from the binder can be washed away together with the rare gas. Therefore, it becomes possible to reduce the cleaning work frequency of the heat treatment apparatus, and to improve the operation rate of the heat treatment apparatus.

  [Application Example 6] A method of manufacturing a capacitor according to the application example described above, wherein the step (2) is performed in a vacuum or in an atmosphere in which a rare gas is at normal pressure or reduced pressure, and sintering and hydrogen removal are performed. It is characterized in that it is performed at the same time as the step (2) and the step (3).

  According to the application example described above, the manufacturing process can be shortened. By using a turbo-molecular pump with a large displacement in the exhaust system, exhausting gas caused by organic matter (referred to as a binder) that is suitably mixed when shaping degassed pellets due to heating. It is possible to perform the step of reforming the granular pellets into sintered pellets and the hydrogen removal at the same time. In addition, when a rare gas atmosphere is used, it is possible to flow away the degass derived from the binder together with the rare gas. Therefore, it becomes possible to reduce the cleaning work frequency of the heat treatment apparatus, and to improve the operation rate of the heat treatment apparatus.

  Application Example 7 In the method of manufacturing a capacitor according to the application example described above, the oxide layer has a film thickness of 2 nm or more and 20 nm or less.

  According to the application example described above, since the oxide pellet functions as a hydrogen barrier layer when the sintered pellet is opened to the atmosphere or anodized by providing a film thickness of 2 nm or more, the sintered pellet The hydrogen absorption can be suppressed.

  Moreover, an anodic oxide layer having a sufficient thickness can be formed by providing a film thickness of 20 nm or less. Anodization is selectively formed in a region where current flows easily (region where electrical insulation is weak). Therefore, by increasing the ratio of the anodic oxide layer, it becomes possible to increase the uniformity of the electrical characteristics of the oxide layer that becomes the dielectric layer of the capacitor.

  Application Example 8 In the method of manufacturing a capacitor according to the application example described above, the step (4) is performed at a temperature of room temperature to 800 ° C.

  According to the application example described above, it is possible to obtain a dense oxide layer having a high hydrogen barrier property by forming the oxide layer at a temperature of room temperature or higher. In addition, by forming the oxide layer at a temperature of 800 ° C. or lower, the oxide layer can be formed without damaging the sintered pellet.

  Application Example 9 A method for manufacturing a capacitor according to the application example described above, characterized by performing heat treatment at 200 ° C. or more and 800 ° C. or less without exposure to the air after the step (4).

  According to the application example described above, by performing the heat treatment at a temperature of 200 ° C. or higher, the oxide layer is modified, so that a dense oxide layer having a high hydrogen barrier property can be obtained. Further, by performing the heat treatment at a temperature of 800 ° C. or less, it becomes possible to modify the oxide layer without damaging the sintered pellet.

Sectional drawing which shows the principal part of a capacitor | condenser. (A)-(c) is process sectional drawing for demonstrating the manufacturing method of the capacitor | condenser concerning this embodiment. (A)-(c) is process sectional drawing for demonstrating the manufacturing method of the capacitor | condenser concerning this embodiment. (A), (b) is process sectional drawing for demonstrating the manufacturing method of the capacitor | condenser concerning this embodiment.

Hereinafter, embodiments embodying the present invention will be described with reference to the drawings.
(First Embodiment: Condenser Configuration)

  Hereinafter, the configuration of the capacitor will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the main part of the capacitor. Capacitor 100 includes anode lead wire 203, sintered pellet 205, dielectric layer 208, solid electrolyte layer 209 as an electrolyte layer, carbon layer 210, and cathode layer 211. The capacitor 100 has polarity and functions by applying a higher potential to the anode lead wire 203 than the cathode layer 211.

  The anode lead wire 203 is drawn so as to apply a positive voltage to the sintered pellet 205 as the first electrode of the capacitor 100. The sintered pellet 205 is made of tantalum, niobium, or a metal containing both tantalum and niobium, and has a porous shape that can increase the surface area in order to increase the capacity.

  The dielectric layer 208 is disposed so as to cover the sintered pellet 205, and constitutes a charge storage portion of the capacitor 100 in cooperation with the sintered pellet 205 and the solid electrolyte layer 209.

  The solid electrolyte layer 209 is disposed so as to further cover the dielectric layer 208 that covers the sintered pellet 205 having a porous shape, and is disposed so as to fill a gap between the dielectric layer 208 and the carbon layer 210. As a material, manganese dioxide is preferably used.

  The carbon layer 210 is formed between the solid electrolyte layer 209 and the cathode layer 211 so as to reduce the contact resistance between the solid electrolyte layer 209 and the cathode layer 211.

  The cathode layer 211 as the second electrode is disposed so as to cover the carbon layer 210 and is formed using solderable silver or the like.

  Here, the sintered pellet 205 is configured to have a hydrogen content of 2 at% or less. A production method for realizing this amount of hydrogen will be described later. Since the hydrogen content is 2 at% or less, the occurrence of hydrogen embrittlement in tantalum, niobium, or a metal containing both tantalum and niobium can be suppressed. Therefore, the mechanical strength is improved and the impact resistance of the capacitor 100 can be improved. The capacitor 100 has a mechanical strength that is low enough to be destroyed just by dropping it on the floor. However, by suppressing the occurrence of hydrogen embrittlement, the mechanical strength can be increased, and the capacitor 100 having excellent reliability can be obtained.

In addition, the sintered pellet 205 as the first electrode preferably has a density per volume of 3 g / cm ³ or more and 6 g / cm ³ or less. When the density is 3 g / cm ³ or more, the mechanical strength of the sintered pellet 205 can be maintained, and the resistance to mechanical impact can be maintained. Further, by suppressing the density to 6 g / cm ³ or less, the equivalent area of the sintered pellet 205 can be increased, and the power storage amount of the capacitor 100 can be improved (product of breakdown voltage and capacity).

In the present embodiment, an example in which the solid electrolyte layer 209 using manganese dioxide is used as the electrolyte layer has been described. However, as the electrolyte layer, organic substances such as polypyrrole, polyaniline, and polythiophene having excellent conductivity may be used. Further, the electrolyte layer and the second electrode (metal package) may be used by using a metal package filled with the electrolytic solution.
(Second Embodiment: Capacitor Manufacturing Method)

  Hereinafter, a method for manufacturing a capacitor will be described with reference to the drawings. FIGS. 2A to 2C, FIGS. 3A to 3C, FIGS. 4A and 4B are process cross-sectional views for explaining a method of manufacturing a capacitor according to this embodiment.

  First, metal particles 201 are prepared. The metal particles 201 are preferably tantalum, niobium, or an average particle size of 0.05 μm to 5 μm including both tantalum and niobium. By setting the average particle size to 0.05 μm or more, it is possible to suppress the crowding of the metal particles 201, to secure a space for forming a solid electrolyte layer 209 described later, and to improve the capacity utilization rate. Moreover, since the density of the metal particle 201 can be kept high by setting it as 5 micrometers or less, a surface area can be taken large and a capacity | capacitance can be ensured. In particular, in order to obtain a high capacity, it is preferable to use a metal particle 201 having a particle size of 0.2 μm to 0.5 μm. Moreover, when a high pressure | voltage resistance is required, it is preferable to make the average particle diameter of the metal particle 201 high at the anodic oxidation process mentioned later. In the anodizing step, the metal layer 201 is consumed (oxidized) to form a dielectric layer 208 described later. When increasing the thickness of the oxide layer, the particle size is increased so that the metal particles 201 remain so that the sintered pellet 205 remains in a granular state after the anodic oxidation step of the metal particles 201 is completed. Thus, the dielectric layer 208 can be formed, and the capacitance can be secured.

  Next, after mixing the binder 202 which melt | dissolved acrylic resin etc. with the organic solvent in the metal particle 201, the granular pellet 204 is formed by carrying out press compression formation in the state which inserted the anode lead wire 203. FIG. FIG. 2A shows a cross-sectional view after the steps so far are completed.

  Subsequently, sintering is performed at a temperature of about 1400 ° C. to form sintered pellets 205. In this heat treatment step, the binder 202 disappears from the granular pellets 204, so that it does not remain in the sintered pellets 205. Further, the natural oxide layer covering the metal particles 201 disappears by this heat treatment. FIG. 2B shows a cross-sectional view after the steps so far are completed.

Next, the sintered pellet 205 is heated to a temperature of about 400 ° C. to about 1000 ° C. in a vacuum (for example, about 10 ⁻³ Pa) to dehydrogenate the sintered pellet 205. In this case, heat treatment may be performed in an atmosphere of a rare gas such as argon instead of the heat treatment in a vacuum state. Further, as the rare gas atmosphere, either a reduced pressure atmosphere or a normal pressure atmosphere may be used. In this case, the dehydrogenation treatment can be performed by performing a heat treatment in a state where the hydrogen partial pressure or the oxidizing species partial pressure is lower than the atmosphere.

Here, the step of forming the granular pellet 204 and the dehydrogenation of the sintered pellet 205 can be performed at the same time, and the granular pellet 204 is sintered in a vacuum (for example, about 10 ⁻³ Pa). By performing this, it is possible to simultaneously perform the formation of the sintered pellet 205 and the dehydrogenation. In this case, since gas due to the binder 202 is generated, for example, it is preferable to use a turbo molecular pump or the like having a large displacement, and a high degree of vacuum can be maintained even in a state where gas is generated. Further, in the initial stage of heating (in the state where gas due to the binder 202 is generated), heat treatment may be performed by lowering the degree of vacuum, and dehydrogenation may be performed by raising the degree of vacuum when the degassing amount is reduced. .

  In this case, it is also preferable to perform heat treatment in an atmosphere of a rare gas such as argon instead of heat treatment in a vacuum state. As the rare gas atmosphere, either a reduced pressure atmosphere or a normal pressure atmosphere may be used. In this case, the dehydrogenation treatment can be performed by performing a heat treatment in a state where the hydrogen partial pressure or the oxidizing species partial pressure is lower than that in the atmosphere. In addition, since the rare gas is flowing, it is possible to suppress the phenomenon that the substance due to the binder 202 adheres to the inside of the heat treatment apparatus, it is possible to reduce the cleaning work frequency of the heat treatment apparatus, and the operation rate of the heat treatment apparatus. Can be improved. Nitrogen may be used as the inert atmosphere. However, since tantalum and niobium react with nitrogen at a high temperature, the heat treatment is performed with the nitrogen removed at a heat treatment temperature (for example, 600 ° C. or higher). May be preferred. FIG. 2C shows a process cross-sectional view in a state where dehydrogenation is performed.

  Next, oxidation is performed without exposing the sintered pellet 205 to the atmosphere, and the sintered pellet 205 is newly provided with an oxide layer. The oxidation is preferably performed at a temperature of room temperature or higher and 800 ° C. or lower, and preferably has a thickness of 2 nm or more and 20 nm or less, and a dense dielectric layer having a high hydrogen barrier property compared to a normal natural oxide layer. A part of the oxide layer 208A can be obtained. In addition, the sintered pellet 205 main body remains stable in this temperature range.

  In addition, when the oxidation is performed near room temperature, the denseness of the oxide layer 208A is slightly reduced. Therefore, it is preferable to perform annealing at a temperature of 200 ° C. or higher and 800 ° C. or lower after the oxidation step. Absent. In this case, since the layer quality of the oxide layer 208A is dense, it is possible to obtain a dense oxide layer having a high hydrogen barrier property. In addition, the sintered pellet 205 remains stable in this temperature range. By performing the steps so far, a new oxide layer 208A is added to the sintered pellet 205 containing no hydrogen. The oxide layer 208A has a hydrogen barrier property, and even if the sintered pellet 205 is exposed to the atmosphere, absorption of hydrogen contained in the atmosphere can be prevented. In this step, an oxide layer is also formed on the surface of the anode lead wire 203 at the same time. FIG. 3A shows a cross-sectional view after the steps so far are completed.

  Next, the sintered pellet 205 containing no hydrogen and covered with the oxide layer 208A is taken out into the atmosphere and anodized. By this treatment, a new anodized layer 208B is added to the sintered pellet 205. Anodic oxidation is performed by immersing in an electrolytic solution in which an electrolyte such as nitric acid, phosphoric acid, sulfuric acid, carboxylic acid, etc. is dissolved, and applying voltage to anodize, and a dielectric of about 20 nm to 300 nm depending on the required breakdown voltage. An anodized layer 208B is formed as a part of the layer. A combination of the oxide layer 208A and the anodic oxide layer 208B functions as the dielectric layer 208.

  In the anodic oxidation process, a phenomenon occurs in which hydrogen is concentrated in the sintered pellet 205 so as to be swept up, so that the hydrogen concentration in the sintered pellet 205 changes and is affected by the influence of the anodic oxide layer 208B. Although a phenomenon in which the characteristics change may be observed, as in this embodiment, anodization is performed with hydrogen sufficiently removed to obtain an anodized layer (dielectric layer) 208B having high reproducibility. Is possible. FIG. 3B shows a cross-sectional view after the steps so far are completed.

  Next, after the chemical conversion liquid is removed by washing and drying, a solid electrolyte layer 209 made of manganese dioxide is newly formed on the sintered pellet 205 provided with the dielectric layer 208, and the sintered pellet 205 is used as a constituent material. Add. In order to form the solid electrolyte layer 209, the sintered pellet 205 provided with the dielectric layer 208 is immersed in a manganese nitrate solution with the lead surface side of the anode lead wire 203 facing upward. As a result, the sintered pellet 205 provided with the dielectric layer 208 is impregnated with the manganese nitrate solution. After impregnation, it decomposes by heating to precipitate manganese dioxide. Then, the concentration of the manganese nitrate solution is successively increased, and these impregnation and precipitation steps are repeated to form a solid electrolyte layer 209 made of manganese dioxide so as to fill the gaps in the dielectric layer 208. FIG. 3C shows a cross-sectional view after the steps so far are completed.

  Next, the sintered pellet 205 provided with the solid electrolyte layer 209 is placed in the carbon paste liquid with the lead-out surface side of the anode lead wire 203 up, and the liquid surface is slightly above the lead-out surface side of the anode lead wire 203. Soak so. After immersion, the carbon layer 210 is formed by drying. FIG. 4A shows a cross-sectional view after the steps so far are completed.

  Then, the sintered pellet 205 on which the carbon layer 210 is formed is immersed in the silver paste liquid so that the liquid level is slightly above the lead-out surface side of the anode lead wire 203. After immersion, the cathode layer 211 made of foil-like silver is formed by drying. FIG. 4B shows a cross-sectional view after the steps so far are completed. Thereafter, the capacitor 100 is formed by performing an aging process or a mounting process.

  A feature of this manufacturing process is that a dehydrogenation process is performed before the sintered pellet 205 is exposed to the atmosphere, and an oxide layer 208A that functions as a hydrogen barrier layer is formed. By forming the oxide layer 208A, it is possible to prevent the absorption of hydrogen into the sintered pellet 205 even when immersed in the atmosphere or a chemical conversion solution for anodization. Since the brittleness can be overcome, it is possible to suppress the occurrence of defects due to mechanical shock of the capacitor 100, and it is possible to disclose a manufacturing method for providing the capacitor 100 with higher reliability.

  DESCRIPTION OF SYMBOLS 100 ... Capacitor 201 ... Metal particle, 202 ... Binder, 203 ... Anode lead wire, 204 ... Granular pellet, 205 ... Sintered pellet, 208 ... Dielectric layer, 208A ... Oxidation layer, 208B ... Anodization layer, 209 ... Solid electrolyte Layer 210... Carbon layer 211. Cathode layer.

Claims (9)

A first electrode made of tantalum, niobium, or a metal containing both tantalum and niobium;
A second electrode;
A dielectric layer located between the first electrode and the second electrode and made of tantalum oxide, niobium oxide, or an oxide containing both tantalum and niobium;
An electrolyte layer positioned between the dielectric layer and the second electrode,
The capacitor according to claim 1, wherein a hydrogen content in the first electrode is 2 at% or less. The capacitor of claim 1,
The capacitor is characterized in that the first electrode has a structure including a void having a density of 3 g / cm ³ or more and 6 g / cm ³ or less. (1) tantalum, niobium, or metal particles composed of tantalum and niobium having an average particle size of 0.05 μm or more and 5 μm or less are compressed in a state of including a part of lead wires containing tantalum, niobium, or both tantalum and niobium. Molding and forming granular pellets;
(2) Sintering the granular pellets, combining the metal particles constituting the granular pellets and modifying them into sintered pellets;
(3) heating the sintered pellet in a state where the partial pressures of hydrogen and oxygen are lowered, and removing hydrogen in the sintered pellet;
(4) introducing oxygen-containing gas without exposing the sintered pellet to the atmosphere, and forming an oxide layer;
(5) a step of anodic oxidation by immersing the sintered pellet formed with the oxide layer in a chemical conversion liquid;
A method for producing a capacitor, comprising:   4. The method for manufacturing a capacitor according to claim 3, wherein the atmosphere in the step (3) is a reduced-pressure atmosphere.   4. The method for manufacturing a capacitor according to claim 3, wherein the atmosphere in the step (3) is a normal pressure or a reduced pressure rare gas atmosphere.   6. The method of manufacturing a capacitor according to claim 3, wherein the step (2) is performed in a vacuum, or in an atmosphere in which a rare gas is normal pressure or reduced pressure, and sintering and hydrogen are performed. A method for producing a capacitor, wherein the step (2) and the step (3) are performed by simultaneously performing removal. It is a manufacturing method of the capacitor according to any one of claims 3 to 6,
The method for manufacturing a capacitor, wherein the oxide layer has a film thickness of 2 nm or more and 20 nm or less.   The method for manufacturing a capacitor according to any one of claims 3 to 7, wherein the step (4) is performed at a temperature of room temperature to 800 ° C.   8. The method of manufacturing a capacitor according to claim 3, wherein after the step (4), heat treatment is performed at 200 ° C. or more and 800 ° C. or less without being exposed to the atmosphere. A method for manufacturing a capacitor.

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