JP4665854B2 - Valve metal composite electrode foil and manufacturing method thereof - Google Patents
Valve metal composite electrode foil and manufacturing method thereof Download PDFInfo
- Publication number
- JP4665854B2 JP4665854B2 JP2006191194A JP2006191194A JP4665854B2 JP 4665854 B2 JP4665854 B2 JP 4665854B2 JP 2006191194 A JP2006191194 A JP 2006191194A JP 2006191194 A JP2006191194 A JP 2006191194A JP 4665854 B2 JP4665854 B2 JP 4665854B2
- Authority
- JP
- Japan
- Prior art keywords
- alloy
- foil
- composite electrode
- valve metal
- electrode foil
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000011888 foil Substances 0.000 title claims description 177
- 239000002905 metal composite material Substances 0.000 title claims description 46
- 238000004519 manufacturing process Methods 0.000 title claims description 21
- 239000003990 capacitor Substances 0.000 claims description 72
- 229910052715 tantalum Inorganic materials 0.000 claims description 62
- 229910052758 niobium Inorganic materials 0.000 claims description 54
- 229910001362 Ta alloys Inorganic materials 0.000 claims description 41
- 239000010408 film Substances 0.000 claims description 37
- 239000000463 material Substances 0.000 claims description 36
- 229910001257 Nb alloy Inorganic materials 0.000 claims description 35
- 229910000838 Al alloy Inorganic materials 0.000 claims description 33
- 230000004888 barrier function Effects 0.000 claims description 33
- 239000007787 solid Substances 0.000 claims description 29
- 239000002131 composite material Substances 0.000 claims description 25
- 229910052802 copper Inorganic materials 0.000 claims description 22
- 238000010438 heat treatment Methods 0.000 claims description 21
- 229910052751 metal Inorganic materials 0.000 claims description 17
- 239000002184 metal Substances 0.000 claims description 17
- 239000002245 particle Substances 0.000 claims description 17
- 229910045601 alloy Inorganic materials 0.000 claims description 16
- 239000000956 alloy Substances 0.000 claims description 16
- 238000000034 method Methods 0.000 claims description 16
- 239000000758 substrate Substances 0.000 claims description 15
- 238000004544 sputter deposition Methods 0.000 claims description 14
- 239000010409 thin film Substances 0.000 claims description 14
- 229910052782 aluminium Inorganic materials 0.000 claims description 13
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 9
- 229910052709 silver Inorganic materials 0.000 claims description 7
- 238000005546 reactive sputtering Methods 0.000 claims description 5
- 238000007740 vapor deposition Methods 0.000 claims description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 3
- 229910001873 dinitrogen Inorganic materials 0.000 claims description 3
- 238000001771 vacuum deposition Methods 0.000 claims description 2
- 239000007864 aqueous solution Substances 0.000 description 13
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 12
- 239000000203 mixture Substances 0.000 description 12
- 229910017604 nitric acid Inorganic materials 0.000 description 12
- 239000000126 substance Substances 0.000 description 10
- 230000000052 comparative effect Effects 0.000 description 9
- 239000000843 powder Substances 0.000 description 9
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 8
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 8
- 238000005530 etching Methods 0.000 description 8
- 239000008188 pellet Substances 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 7
- 150000002739 metals Chemical class 0.000 description 7
- 229920000128 polypyrrole Polymers 0.000 description 7
- 229910052799 carbon Inorganic materials 0.000 description 6
- 238000005259 measurement Methods 0.000 description 6
- 239000012298 atmosphere Substances 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 5
- 230000003647 oxidation Effects 0.000 description 5
- 238000007254 oxidation reaction Methods 0.000 description 5
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 4
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 4
- 238000007743 anodising Methods 0.000 description 4
- 238000007654 immersion Methods 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- 239000002253 acid Substances 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 150000004767 nitrides Chemical class 0.000 description 3
- 238000006116 polymerization reaction Methods 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 238000005245 sintering Methods 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- 238000005229 chemical vapour deposition Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000012299 nitrogen atmosphere Substances 0.000 description 2
- WYXIGTJNYDDFFH-UHFFFAOYSA-Q triazanium;borate Chemical compound [NH4+].[NH4+].[NH4+].[O-]B([O-])[O-] WYXIGTJNYDDFFH-UHFFFAOYSA-Q 0.000 description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 239000010407 anodic oxide Substances 0.000 description 1
- 238000002048 anodisation reaction Methods 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 238000010549 co-Evaporation Methods 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000003989 dielectric material Substances 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 239000002019 doping agent Substances 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 229910052735 hafnium Inorganic materials 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 229920000123 polythiophene Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 238000007751 thermal spraying Methods 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Landscapes
- Physical Vapour Deposition (AREA)
- Fixed Capacitors And Capacitor Manufacturing Machines (AREA)
Description
本発明は、固体電解コンデンサの電極箔および製造方法に関する。 The present invention relates to an electrode foil and manufacturing method for a solid electrolytic capacitor.
近年、電子機器の小型化および高機能化に伴い、電子回路の小型化、高集積化、および動作周波数の高周波化が進められている。電子回路に用いられる受動部品に関しても同様に、小型化および高特性化が求められており、例えば、コンデンサに関しても、可能な限り小型、低背、大容量および低インピーダンスであることが求められている。 In recent years, along with miniaturization and high functionality of electronic devices, miniaturization, high integration, and high operating frequency of electronic circuits have been promoted. Similarly, passive components used in electronic circuits are also required to be smaller and have higher characteristics. For example, capacitors are also required to be as small, low profile, large capacity, and low impedance as possible. Yes.
体積当たりの静電容量が大きいコンデンサとして、バルブメタルを陽極体として、その陽極酸化皮膜を誘電体とした電解コンデンサが、広く使用されており、例えば、電気化学的なエッチングで粗面化したＡｌ箔を陽極酸化してＡｌ2Ｏ3を形成したＡｌ電解コンデンサ、Ｔａの多孔質ペレットを陽極酸化してＴａ2Ｏ5を形成したＴａ電解コンデンサ、および、Ｎｂの多孔質ペレットを陽極酸化してＮｂ2Ｏ5を形成したＮｂ電解コンデンサが挙げられる。中でも、Ｔａ2Ｏ5（誘電率２４〜２７）、および、Ｎｂ2Ｏ5（誘電率４１）は、Ａｌ2Ｏ3（誘電率７〜１０）に比較して、誘電率が大きいため、ＴａやＮｂは、小型大容量の電解コンデンサの素材として、Ａｌより適している。 As a capacitor having a large capacitance per volume, an electrolytic capacitor having a valve metal as an anode body and an anodic oxide film as a dielectric is widely used. For example, Al roughened by electrochemical etching. An Al electrolytic capacitor formed by anodizing a foil to form Al 2 O 3 , a Ta electrolytic capacitor formed by anodic oxidation of Ta porous pellets to form Ta 2 O 5 , and an anodizing of porous Nb pellets An Nb electrolytic capacitor in which Nb 2 O 5 is formed is mentioned. Among them, Ta 2 O 5 (dielectric constant 24-27) and Nb 2 O 5 (dielectric constant 41) have a higher dielectric constant than Al 2 O 3 (dielectric constant 7-10). Nb is more suitable than Al as a material for a small-capacity electrolytic capacitor.
一般的なＴａ電解コンデンサまたはＮｂ電解コンデンサは、図５に示すように、ＴａまたはＮｂからなるワイヤ（２）を差し込んだ状態で、Ｔａ粉末やＮｂ粉末を、圧粉成型および焼結して製造された多孔質ペレット（１）を陽極体として用いている。サブミクロンのＴａ粉末やＮｂ粉末を利用することにより、表面積の非常に大きな多孔質ペレットが得られるが、製法から多孔質ペレットの小型化および薄型化には限界があるため、得られるＴａ電解コンデンサまたはＮｂ電解コンデンサの小型化および低背化にも、おのずと限界が生じる。 As shown in FIG. 5, a general Ta electrolytic capacitor or Nb electrolytic capacitor is manufactured by compacting and sintering Ta powder or Nb powder with a wire (2) made of Ta or Nb inserted. The made porous pellet (1) is used as an anode body. Porous pellets with a very large surface area can be obtained by using submicron Ta powder or Nb powder, but there is a limit to reducing the size and thickness of porous pellets from the manufacturing method, so the obtained Ta electrolytic capacitor Or, there is a limit to the reduction in size and height of the Nb electrolytic capacitor.
これに対して、例えば、特許文献１（米国特許第３８８９３５７号公報）に開示されているように、Ｔａ電解コンデンサまたはＮｂ電解コンデンサにおいて、さらなる小型化および低背化を図るために、Ｔａ粉末またはＮｂ粉末をペースト状にして、Ｔａ箔またはＮｂ箔に塗布して焼成し、箔状の陽極体を得ることが、以前から試みられている。しかし、この方法では、焼結収縮により焼結体にクラックが生じやすい。また、粉末と箔の間よりも、粉末同士の焼結が進行しやすいため、焼結体と箔の界面での密着性が十分に得られない。これらのようなクラック発生や密着力不足は、コンデンサ製造工程でのハンドリング中に、焼結体が箔から剥離したり、漏れ電流特性の悪化を招き、好ましくない。 On the other hand, for example, as disclosed in Patent Document 1 (US Pat. No. 3,889,357), Ta powder capacitors or Nb electrolytic capacitors have Ta powder or It has been attempted for some time to obtain a foil-like anode body by making Nb powder into a paste, applying it to Ta foil or Nb foil, and baking it. However, in this method, cracks are likely to occur in the sintered body due to sintering shrinkage. In addition, since the sintering of the powder is more likely to proceed than between the powder and the foil, sufficient adhesion at the interface between the sintered body and the foil cannot be obtained. The occurrence of cracks and insufficient adhesion as described above are not preferable because the sintered body is peeled off from the foil during handling in the capacitor manufacturing process or the leakage current characteristics are deteriorated.
また、特許文献２（特開２００６−４９８１６号公報）においては、ＴａやＮｂと、それらと相溶性を持たない異相成分を混合して、成膜し、真空中または不活性ガス中で熱処理をした後に、異相成分のみを選択的に除去するという方法で、ＴａやＮｂからなる多孔質層を有する箔状陽極体を製造することが開示されている。このように製造される箔状陽極体の断面図を図６に示す。得られる箔状陽極体により、コンデンサのさらなる小型化および低背化に有効である。しかしながら、これらの箔状陽極体は、希少金属であるＴａ箔やＮｂ箔を、多孔質層（４）以外に、基板（３）として用いているため、従来の圧粉成型ペレットに比べて、ＴａやＮｂの使用量が多くなり、箔状陽極体のコストが高くなってしまうという問題がある。 Moreover, in patent document 2 (Unexamined-Japanese-Patent No. 2006-49816), Ta and Nb and the heterophasic component which is not compatible with them are mixed, it forms into a film, and it heat-processes in a vacuum or inert gas After that, it is disclosed that a foil-like anode body having a porous layer made of Ta or Nb is produced by a method of selectively removing only the heterogeneous components. A cross-sectional view of the foil-like anode body manufactured in this way is shown in FIG. The obtained foil-like anode body is effective for further downsizing and lowering the capacitor. However, these foil-like anode bodies use rare metals such as Ta foil and Nb foil as the substrate (3) in addition to the porous layer (4), so compared to conventional compacted pellets, There is a problem that the amount of Ta and Nb used increases and the cost of the foil-like anode body increases.
一方、電解コンデンサの低インピーダンス化という観点からは、薄型の固体電解コンデンサ素子を複数個、積層して、電気的に接続することが、有効である。従来の積層型固体電解コンデンサとして、例えば、特許文献３（特開平１１−１３５３６７号公報）には、薄型の固体電解コンデンサ素子を積層して得られる積層型固体電解コンデンサが開示されている。この方法は、コンデンサの低インピーダンス化には有効であるが、箔状陽極体として、エッチングしたＡｌ箔を使用しているため、前述のように、ＴａやＮｂからなる固体電解コンデンサに比べて、体積あたりの静電容量密度が低くなってしまうという問題がある。 On the other hand, from the viewpoint of lowering the impedance of the electrolytic capacitor, it is effective to stack a plurality of thin solid electrolytic capacitor elements and electrically connect them. As a conventional multilayer solid electrolytic capacitor, for example, Patent Document 3 (Japanese Patent Laid-Open No. 11-135367) discloses a multilayer solid electrolytic capacitor obtained by stacking thin solid electrolytic capacitor elements. Although this method is effective for lowering the impedance of the capacitor, since an etched Al foil is used as the foil-like anode body, as described above, compared to a solid electrolytic capacitor made of Ta or Nb, There is a problem that the capacitance density per volume becomes low.
また、前述の特許文献２（特開２００６−４９８１６号公報）のように、ＴａまたはＮｂからなる箔状陽極体を使用して、薄型の固体電解コンデンサ素子を利用することは、体積あたりの静電容量密度の向上に有効であると考えられるが、前述したように、希少金属であるＴａやＮｂの使用量が増えるため、箔状陽極体のコスト増につながる。また、電解コンデンサの低インピーダンス化には、コンデンサの等価直列抵抗（ＥＳＲ）の低減が重要であり、箔状陽極体の抵抗も可能な限り低いことが望ましい。しかしながら、ＴａやＮｂは、体積抵抗率が比較的高いため（Ｔａの体積抵抗率：１３．５μΩｃｍ、Ｎｂの体積抵抗率：１４．５μΩｃｍ）、ＴａやＮｂからなる箔状陽極体の抵抗は、エッチングしたＡｌ箔（Ａｌの体積抵抗率：２．７μΩｃｍ）に比較して、大きくなってしまうという問題もある。
本発明は、かかる問題点を解決するためになされたものであって、積層型固体電解コンデンサの作製に適し、エッチングＡｌ箔よりも高容量密度であり、かつ、同等の電極抵抗を有し、さらに、高価な希少金属であるＴａやＮｂの使用量を減らした、低コストの電解コンデンサ用電極箔およびその製造方法を提供することを目的とする。 The present invention has been made in order to solve such problems, and is suitable for the production of a multilayer solid electrolytic capacitor, has a higher capacity density than an etched Al foil, and has an equivalent electrode resistance, It is another object of the present invention to provide a low-cost electrode foil for electrolytic capacitors and a method for manufacturing the same, in which the amount of expensive rare metals Ta and Nb is reduced.
本発明のバルブ金属複合電極箔は、Ａｌ箔またはＡｌ合金箔を基材とし、該基材の片面または両面に形成されたＴａまたはＴａ合金の緻密層と、該緻密層の上に形成され、ＴａまたはＴａ合金の多孔質層とからなる積層構造を有し、前記多孔質層が、見かけ面積に対して２倍以上の表面積を持つことを特徴とする。 The valve metal composite electrode foil of the present invention comprises an Al foil or an Al alloy foil as a base material, a dense layer of Ta or Ta alloy formed on one or both surfaces of the base material, and formed on the dense layer, It has a laminated structure composed of a Ta or Ta alloy porous layer, and the porous layer has a surface area that is twice or more the apparent area.
あるいは、Ａｌ箔またはＡｌ合金箔を基材とし、該基材の片面または両面に形成されたＮｂまたはＮｂ合金の緻密層と、該緻密層の上に形成され、ＮｂまたはＮｂ合金の多孔質層とからなる積層構造を有し、前記多孔質層が、見かけ面積に対して２倍以上の表面積を持つことを特徴とする。 Alternatively, an Al foil or Al alloy foil is used as a base material, a dense layer of Nb or Nb alloy formed on one or both sides of the base material, and a porous layer of Nb or Nb alloy formed on the dense layer The porous layer has a surface area that is at least twice as large as the apparent area.
前記基材と前記緻密層の間に、Ｔａ、Ｔａ合金、Ｎｂ、Ｎｂ合金、ＡｌおよびＡｌ合金に対して熱力学的に安定なバリア層を設けることが好ましい。 It is preferable to provide a barrier layer that is thermodynamically stable against Ta, Ta alloy, Nb, Nb alloy, Al, and Al alloy between the base material and the dense layer.
前記バリア層は、ＴｉＮ、ＺｒＮおよびＨｆＮから選ばれるいずれか一種であることが好ましい。 The barrier layer is preferably any one selected from TiN, ZrN, and HfN.
前記基材の厚さは、１００μｍ以下であることが好ましい。 The thickness of the substrate is preferably 100 μm or less.
さらに、前記多孔質層の空隙率は、３０〜７０％の範囲内であることが好ましい。 Furthermore, the porosity of the porous layer is preferably in the range of 30 to 70%.
本発明のバルブ金属複合電極箔の製造方法は、Ａｌ箔またはＡｌ合金箔の基材に、ＴａまたはＴａ合金の緻密層を形成し、得られた緻密層の上に、ＴａまたはＴａ合金、および、Ｔａと相溶しない異相成分が、粒子径１ｎｍ〜１μｍで均一に分布した合金薄膜を形成し、真空熱処理をすることにより、ＴａまたはＴａ合金、および、前記異相成分を粒調整した後に、前記異相成分を溶解除去することを特徴とする。 The method for producing a valve metal composite electrode foil of the present invention comprises forming a Ta or Ta alloy dense layer on an Al foil or Al alloy foil base material, Ta or Ta alloy on the obtained dense layer, and After forming the alloy thin film in which the heterogeneous component incompatible with Ta is uniformly distributed with a particle diameter of 1 nm to 1 μm and subjecting the Ta or Ta alloy and the heterogeneous component to grain adjustment by vacuum heat treatment, It is characterized by dissolving and removing heterogeneous components.
あるいは、Ａｌ箔またはＡｌ合金箔の基材に、ＮｂまたはＮｂ合金の緻密層を形成し、得られた緻密層の上に、ＮｂまたはＮｂ合金、および、Ｎｂと相溶しない異相成分が、粒子径１ｎｍ〜１μｍで均一に分布した合金薄膜を形成し、真空熱処理をすることにより、ＮｂまたはＮｂ合金、および、前記異相成分を粒調整した後に、前記異相成分を溶解除去することを特徴とする。 Alternatively, a dense layer of Nb or Nb alloy is formed on the base material of Al foil or Al alloy foil, and Nb or Nb alloy and a different phase component incompatible with Nb are formed on the obtained dense layer. An alloy thin film having a diameter of 1 nm to 1 μm that is uniformly distributed is formed, and vacuum heat treatment is performed to adjust Nb or Nb alloy and the heterogeneous component, and then dissolve and remove the heterogenous component. .
前記基材と前記緻密層の間に、Ｔａ、Ｔａ合金、Ｎｂ、Ｎｂ合金、ＡｌおよびＡｌ合金に対して熱力学的に安定なバリア層を形成することが好ましい。 It is preferable to form a thermodynamically stable barrier layer with respect to Ta, Ta alloy, Nb, Nb alloy, Al and Al alloy between the base material and the dense layer.
前記バリア層を、ＴｉＮ、ＺｒＮおよびＨｆＮから選ばれるいずれか一種とすることが好ましい。また、該バリア層は、窒素ガスを導入した反応性スパッタリングまたは反応性蒸着により形成することが好ましい。 The barrier layer is preferably any one selected from TiN, ZrN, and HfN. Further, the barrier layer is preferably formed by reactive sputtering or reactive vapor deposition in which nitrogen gas is introduced.
前記合金薄膜に対する前記異相成分の添加量を、３０〜７０体積％の範囲内とすることが好ましい。また、前記合金薄膜の形成に、スパッタリング法または真空蒸着法を用いることが好ましい。 The amount of the heterogeneous component added to the alloy thin film is preferably in the range of 30 to 70% by volume. Moreover, it is preferable to use a sputtering method or a vacuum evaporation method for forming the alloy thin film.
前記異相成分を、ＣｕまたはＡｇとすることが好ましい。または、前記異相成分を、Ｍｇ、Ｃａ、またはこれらの酸化物とすることが好ましい。 The heterogeneous component is preferably Cu or Ag. Alternatively, the heterogeneous component is preferably Mg, Ca, or an oxide thereof.
本発明の固体電解コンデンサは、本発明に係るバルブ金属複合電極箔に定電圧化成処理を施したものを陽極体として用いていることを特徴とする。 The solid electrolytic capacitor of the present invention is characterized in that a valve metal composite electrode foil according to the present invention is subjected to constant voltage conversion treatment as an anode body.
本発明のバルブ金属複合電極箔は、多孔質層にＴａ、Ｔａ合金、ＮｂまたはＮｂ合金を用いているため、エッチングＡｌ箔よりも体積あたりの静電容量密度が大きい。また、基材としてＡｌまたはＡｌ合金を用いているため、Ｔａ単体やＮｂ単体の電極箔に比べて、電極抵抗を下げることができ、電解コンデンサの等価直列抵抗の低減に有利である。さらに、希少金属であるＴａやＮｂの使用量が少なくて済むため、Ｔａ単体やＮｂ単体の電極箔に比べて、電極箔のコストを下げることができる。 Since the valve metal composite electrode foil of the present invention uses Ta, Ta alloy, Nb or Nb alloy for the porous layer, the capacitance density per volume is larger than the etching Al foil. In addition, since Al or Al alloy is used as the base material, the electrode resistance can be lowered compared with the electrode foil of Ta alone or Nb alone, which is advantageous in reducing the equivalent series resistance of the electrolytic capacitor. Furthermore, since the usage amount of rare metals Ta and Nb can be reduced, the cost of the electrode foil can be reduced as compared with the electrode foil made of Ta alone or Nb alone.
以上のことから、本発明のバルブ金属複合電極箔は、電解コンデンサの陰極および陽極箔として好適に用いることができる。また、薄型固体電解コンデンサや積層型固体電解コンデンサの陽極箔としても好適である。 From the above, the valve metal composite electrode foil of the present invention can be suitably used as a cathode and an anode foil of an electrolytic capacitor. It is also suitable as an anode foil for thin solid electrolytic capacitors and multilayer solid electrolytic capacitors.
小型、薄型、かつ、大容量であるコンデンサの作製には、誘電率の差から、エッチングＡｌ箔よりも、ＴａやＮｂからなる電極箔が有利である。一方、コンデンサの等価直列抵抗の低減には、電極箔の基材として、ＴａやＮｂよりも体積抵抗率の低い金属を使用することが有利であり、このような金属を用いることにより、希少金属であるＴａやＮｂの使用量を減らすことができるため、電極箔がより低コストに製造できる。 For manufacturing a small, thin, and large-capacity capacitor, an electrode foil made of Ta or Nb is more advantageous than an etched Al foil because of the difference in dielectric constant. On the other hand, in order to reduce the equivalent series resistance of the capacitor, it is advantageous to use a metal having a volume resistivity lower than that of Ta or Nb as the base material of the electrode foil. By using such a metal, a rare metal is used. Since the amount of Ta and Nb used can be reduced, the electrode foil can be manufactured at a lower cost.
本発明者らは、このような知見から鋭意研究を進め、ＴａやＮｂよりも体積抵抗率が数倍小さく、かつ、低コストであるＡｌ箔の基材の上に、ＴａやＮｂの多孔質層を形成する方法を見出した。このことにより、従来のエッチングＡｌ箔よりも、高容量密度であり、Ｔａ単体やＮｂ単体である電極箔よりも、電極抵抗が小さく、さらに安価なバルブ金属の複合電極箔が得られることを見出し、発明を完成するに至った。 The inventors of the present invention have made extensive studies based on such knowledge, and have Ta or Nb porous on an Al foil base material having a volume resistivity several times smaller than Ta and Nb and low cost. A method for forming the layer was found. As a result, it has been found that a composite electrode foil of a valve metal having a higher capacity density than conventional etching Al foil, a lower electrode resistance than an electrode foil made of Ta alone or Nb alone, and an inexpensive valve metal can be obtained. The present invention has been completed.
図１に、本発明のバルブ金属複合電極箔の一態様を、断面図で示す。この態様のバルブ金属複合電極箔は、ＴａまたはＴａ合金の緻密層（６）と、緻密層（６）の上に形成され、ＴａまたはＴａ合金の多孔質層（７）とからなる積層構造を有し、この積層構造は、Ａｌ箔またはＡｌ合金箔の基材（５）の片面または両面に形成され、多孔質層（７）が、見かけ面積に対して２倍以上の表面積を持つ。 In FIG. 1, the one aspect | mode of the valve metal composite electrode foil of this invention is shown with sectional drawing. The valve metal composite electrode foil of this aspect has a laminated structure comprising a dense layer (6) of Ta or Ta alloy and a porous layer (7) of Ta or Ta alloy formed on the dense layer (6). This laminated structure is formed on one side or both sides of the Al foil or Al alloy foil substrate (5), and the porous layer (7) has a surface area that is twice or more the apparent area.
図２に、本発明のバルブ金属複合電極箔の異なる態様を、断面図で示す。この態様のバルブ金属複合電極箔は、Ｔａ、Ｔａ合金、ＡｌおよびＡｌ合金に対して熱力学的に安定なバリア層（８）と、バリア層（８）の上に形成され、ＴａまたはＴａ合金の緻密層（６）と、緻密層（６）の上に形成され、ＴａまたはＴａ合金の多孔質層（７）とからなる積層構造を有し、この積層構造は、Ａｌ箔またはＡｌ合金箔の基材（５）の片面または両面に形成され、多孔質層（７）が、見かけ面積に対して２倍以上の表面積を持つ。 In FIG. 2, the different aspect of the valve | bulb metal composite electrode foil of this invention is shown with sectional drawing. The valve metal composite electrode foil of this embodiment is formed on a barrier layer (8) thermodynamically stable against Ta, Ta alloy, Al and Al alloy, and on the barrier layer (8). The layered structure (6) and a layered structure formed on the layer (6) and made of Ta or a Ta alloy porous layer (7) have an Al foil or Al alloy foil. The porous layer (7) is formed on one side or both sides of the substrate (5) and has a surface area that is twice or more the apparent area.
なお、いずれの態様においても、ＴａまたはＴａ合金に代えて、ＮｂまたはＮｂ合金を用いることができる。 In any embodiment, Nb or Nb alloy can be used instead of Ta or Ta alloy.
本発明のバルブ金属複合電極箔の基材の厚さとしては、１００μｍ以下であることが好ましい。このことは、電極箔の見かけ面積あたりの静電容量が、多孔質層の厚さに比例して増加するため、基材が薄く、かつ、多孔質層が厚いほど、見かけ面積当たりの静電容量が大きい電極箔が得られるという理由に基づく。基材の厚さが１００μｍを超える場合、従来のエッチングＡｌ箔に対して、静電容量密度の優位性が小さくなるため、好ましくない。 The thickness of the base material of the valve metal composite electrode foil of the present invention is preferably 100 μm or less. This is because the electrostatic capacity per apparent area of the electrode foil increases in proportion to the thickness of the porous layer, so that the thinner the base material and the thicker the porous layer, the electrostatic capacity per apparent area. This is based on the reason that an electrode foil having a large capacity can be obtained. When the thickness of the base material exceeds 100 μm, it is not preferable because the superiority of the capacitance density is reduced with respect to the conventional etching Al foil.
なお、本明細書における「見かけ面積」とは、電極箔の表面に凹凸がないと仮定した場合の電極箔の面積をいい、実質的に基材の表面積に等しい。多孔質層を片面に形成する場合には、片面の見かけ面積が基準となり、両面に形成する場合には、両面の見かけ面積が基準となる。 The “apparent area” in this specification refers to the area of the electrode foil on the assumption that the surface of the electrode foil is not uneven, and is substantially equal to the surface area of the substrate. When the porous layer is formed on one side, the apparent area on one side is the standard, and when it is formed on both sides, the apparent area on both sides is the standard.
本発明のバルブ金属複合電極箔の多孔質層は、空隙率が３０〜７０％の範囲内であることが好ましい。電解コンデンサの電極箔として、多孔質層が十分な強度と表面積を有している必要がある。空隙率が３０％未満では、多孔質層の強度は十分であるが、見かけ面積あたりの表面積が小さくなってしまったり、多孔質層での異相成分の残留が多くなったり、電解コンデンサ化するときの陰極含浸が難しくなる。逆に、空隙率が７０％を超えると、十分な多孔質層の強度が得られず、多孔質構造の破壊が起こりやすくなるため、好ましくない。 The porous layer of the valve metal composite electrode foil of the present invention preferably has a porosity in the range of 30 to 70%. As an electrode foil of an electrolytic capacitor, the porous layer needs to have sufficient strength and surface area. When the porosity is less than 30%, the strength of the porous layer is sufficient, but when the surface area per apparent area becomes small, the residual of different phase components in the porous layer increases, or when an electrolytic capacitor is formed. It becomes difficult to impregnate the cathode. On the other hand, if the porosity exceeds 70%, a sufficient strength of the porous layer cannot be obtained, and the porous structure is easily broken, which is not preferable.
次に、本発明のバルブ金属複合電極箔の製造方法について、次のように分けられた工程毎に、詳細に説明する。 Next, the manufacturing method of the valve metal composite electrode foil of this invention is demonstrated in detail for every process divided | segmented as follows.
本発明のバルブ金属複合電極箔の製造方法は、［１］Ａｌ箔またはＡｌ合金箔の基材に、ＴａまたはＴａ合金の緻密層を形成する第１工程、［２］得られた緻密層の上に、ＴａまたはＴａ合金、および、Ｔａと相溶しない異相成分が、粒子径１ｎｍ〜１μｍで均一に分布した合金薄膜を成膜する第２工程、［３］真空熱処理をすることにより、ＴａまたはＴａ合金、および、異相成分を粒成長させる第３工程、［４］異相成分を選択的に溶解除去する第４工程からなる。あるいは、ＴａまたはＴａ合金の代わりに、ＮｂまたはＮｂ合金を用いることができる。 The method for producing a valve metal composite electrode foil of the present invention includes: [1] a first step of forming a dense layer of Ta or Ta alloy on a base material of an Al foil or an Al alloy foil, and [2] the obtained dense layer. On top of this, a second step of forming an alloy thin film in which Ta or Ta alloy and a different phase component incompatible with Ta are uniformly distributed with a particle diameter of 1 nm to 1 μm, [3] By performing vacuum heat treatment, Or it consists of a Ta alloy and a third step for grain growth of the different phase component, and [4] a fourth step for selectively dissolving and removing the different phase component. Alternatively, Nb or Nb alloy can be used instead of Ta or Ta alloy.
なお、Ｔａ合金やＮｂ合金としては、電解コンデンサの誘電体となるＴａ2Ｏ5やＮｂ2Ｏ5の皮膜の漏れ電流や熱安定性などを改善するＺｒ、Ｔｉ、ＨｆまたはＡｌなどのバルブメタル、微量のＰ、ＮまたはＢなどのドーパントなどを含んだものを挙げることができる。 Note that Ta alloys and Nb alloys include valve metals such as Zr, Ti, Hf, and Al that improve the leakage current and thermal stability of Ta 2 O 5 and Nb 2 O 5 films that serve as dielectrics for electrolytic capacitors. And a material containing a trace amount of a dopant such as P, N or B.
［１］Ａｌ箔またはＡｌ合金箔の基材に、ＴａまたはＴａ合金（ＮｂまたはＮｂ合金）の緻密層を形成する第１工程：
緻密層は、多孔質層と基材との接合層となる他、後述する異相成分とＡｌ箔またはＡｌ合金箔との合金化を防ぐ役割をする。緻密層を設けずに、例えば、異相成分としてＣｕやＡｇを用い、Ａｌ箔またはＡｌ合金箔に、直接、合金膜を成膜して熱処理を行った場合、ＣｕやＡｇが、直接、基材であるＡｌ箔またはＡｌ合金箔に接するため、続いて行なわれる真空熱処理時に、反応物を形成して、除去しにくくなり、多孔質層が得られなくなったり、多孔質層に異相成分が多く残留して、コンデンサ特性に影響を及ぼしたりするため、好ましくない。
[1] First step of forming a dense layer of Ta or Ta alloy (Nb or Nb alloy) on a substrate of Al foil or Al alloy foil:
The dense layer serves as a bonding layer between the porous layer and the substrate, and also serves to prevent alloying between a heterogeneous component and an Al foil or an Al alloy foil, which will be described later. Without providing a dense layer, for example, when Cu or Ag is used as a heterogeneous component and an alloy film is directly formed on an Al foil or an Al alloy foil and heat treatment is performed, Cu or Ag is directly applied to the substrate. Since it is in contact with the Al foil or Al alloy foil, a reaction product is formed during the subsequent vacuum heat treatment, making it difficult to remove, and a porous layer cannot be obtained, or many different phase components remain in the porous layer. As a result, the capacitor characteristics are affected.
また、緻密層を形成していても、緻密層の膜質や膜厚、熱処理温度によっては、引き続いて行なわれる真空熱処理中に、Ａｌと異相成分の相互拡散が起こり、化合物を形成してしまう場合がある。これに対しては、Ａｌ箔またはＡｌ合金箔上に、Ｔａ、Ｔａ合金、ＡｌおよびＡｌ合金、または、Ｎｂ、Ｎｂ合金、Ａｌ、およびＡｌ合金に対して、熱力学的に安定なバリア層を形成する。得られるバリア層は、真空加熱処理中に、Ｔａ、Ｔａ合金、ＡｌおよびＡｌ合金、または、Ｎｂ、Ｎｂ合金、ＡｌおよびＡｌ合金と反応しにくいため、Ａｌと異相成分の化合物形成をより確実に防ぐことができる。バリア層としては、ＴｉＮ、ＺｒＮまたはＨｆＮを用いることが好ましい。これらは、熱力学的に安定であり、また、体積抵抗率が数百μΩｃｍであるように、比較的高い導電性を有するため、好ましい。バリア層は、バリア効果の観点からは膜質が緻密であるほど好ましい。また、電極抵抗の上昇を極力抑えるという観点からは、抵抗率が比較的大きくなるバリア層の厚さが薄いほど、好ましい。このように、緻密で薄いバリア層は、窒素ガスを導入した反応性スパッタまたは反応性蒸着により形成することが好ましい。なお、バリア層としては、その他、窒化物、例えば、Ｔａ窒化物、Ｎｂ窒化物を用いることができる。 In addition, even if a dense layer is formed, depending on the quality and thickness of the dense layer, and the heat treatment temperature, interdiffusion between Al and different phase components occurs during the subsequent vacuum heat treatment, resulting in the formation of a compound. There is. For this, a barrier layer that is thermodynamically stable against Ta, Ta alloy, Al and Al alloy, or Nb, Nb alloy, Al, and Al alloy on Al foil or Al alloy foil. Form. The resulting barrier layer is unlikely to react with Ta, Ta alloy, Al and Al alloy, or Nb, Nb alloy, Al and Al alloy during vacuum heat treatment, so that formation of compounds of Al and different phase components is more reliably performed. Can be prevented. As the barrier layer, TiN, ZrN or HfN is preferably used. These are preferable because they are thermodynamically stable and have a relatively high conductivity such that the volume resistivity is several hundred μΩcm. The barrier layer is preferably as dense as possible from the viewpoint of the barrier effect. Further, from the viewpoint of suppressing the increase in electrode resistance as much as possible, it is preferable that the barrier layer having a relatively high resistivity is thinner. As described above, the dense and thin barrier layer is preferably formed by reactive sputtering or reactive vapor deposition in which nitrogen gas is introduced. As the barrier layer, other nitrides such as Ta nitride and Nb nitride can be used.
［２］得られた緻密層の上に、ＴａまたはＴａ合金（ＮｂまたはＮｂ合金）、および、Ｔａ（Ｎｂ）と相溶しない異相成分が、粒子径１ｎｍ〜１μｍで均一に分布した合金薄膜を成膜する第２工程：
ＴａまたはＴａ合金、および、Ｔａと相溶しない異相成分、または、ＮｂまたはＮｂ合金、および、Ｎｂと相溶しない異相成分が、粒子径で１ｎｍ〜１μｍの範囲内になかったり、分布が不均一だったりすると、最終的に得られる多孔質層の粒子径や細孔分布が不均一になり、電解コンデンサの特性の悪化を招く。粒子径の範囲や分布の均一性は、粒子径が１００ｎｍ以上の場合は、走査電子顕微鏡などで容易に確認することができる。粒子径が１００ｎｍ以下のように微細な場合でも、透過電子顕微鏡で確認することができる。
[2] On the obtained dense layer, Ta or Ta alloy (Nb or Nb alloy) and an alloy thin film in which a different phase component incompatible with Ta (Nb) is uniformly distributed with a particle diameter of 1 nm to 1 μm Second step of film formation:
Ta or Ta alloy, and heterogeneous component not compatible with Ta, or Nb or Nb alloy, and heterophasic component not compatible with Nb are not in the range of 1 nm to 1 μm in particle diameter, or the distribution is not uniform. If so, the particle size and pore distribution of the finally obtained porous layer become non-uniform, leading to deterioration of the characteristics of the electrolytic capacitor. The uniformity of the particle diameter range and distribution can be easily confirmed with a scanning electron microscope or the like when the particle diameter is 100 nm or more. Even when the particle diameter is as fine as 100 nm or less, it can be confirmed with a transmission electron microscope.
異相成分の添加量としては、体積分率で求め、３０〜７０体積％の範囲内にあることが好ましい。本発明のバルブ金属複合電極箔の多孔質層は、最終的に異相成分を除去することにより得られる。異相成分を完全に除去するためには、異相成分が完全につながっている必要があるが、異相成分の添加量が、体積分率で求めて、３０体積％未満であると、異相成分が完全につながらずに、除去することが困難になり、多孔質層に残留して、見かけ面積あたりの表面積が小さくなってしまったり、電解コンデンサ化するときの陰極含浸が難しくなる。異相成分の添加量が、体積分率で求めて、７０体積％を超えると、異相成分を除去した後に、粒子の接合強度が弱かったり、粒子が完全につながりきれずに、多孔質構造を維持できなくなる。ただし、異相成分の添加量の範囲は、目安であり、異相成分の添加量を絶対的に制限するものではない。膜の配向の程度や使用目的によっては、前記範囲以外となる添加量を採用してもよい。 The addition amount of the heterophasic component is determined by the volume fraction and is preferably in the range of 30 to 70% by volume. The porous layer of the valve metal composite electrode foil of the present invention can be obtained by finally removing the heterogeneous component. In order to completely remove the heterogeneous component, it is necessary that the heterophasic component is completely connected. However, when the added amount of the heterophasic component is less than 30% by volume, the heterophasic component is completely eliminated. However, it becomes difficult to remove, and it remains in the porous layer, and the surface area per apparent area becomes small, or impregnation with the cathode when forming an electrolytic capacitor becomes difficult. If the added amount of the heterogeneous component is determined by volume fraction and exceeds 70% by volume, after removing the heterophasic component, the bonding strength of the particles is weak or the particles are not completely connected and the porous structure is maintained. become unable. However, the range of the added amount of the heterophasic component is a guide and does not absolutely limit the added amount of the heterophasic component. Depending on the degree of orientation of the film and the purpose of use, an additive amount outside the above range may be employed.
異相成分が微細均一に分布した合金薄膜を作製する方法としては、粒度が１ｎｍ〜１μｍの範囲内にある粒子を、揮発性のバインダーに分散して、印刷する方法や、ＣＶＤ（化学蒸着法）、溶射、スパッタリング、蒸着など、種々の方法が考えられる。 As a method for producing an alloy thin film in which the heterogeneous components are finely and uniformly distributed, a method in which particles having a particle size in the range of 1 nm to 1 μm are dispersed in a volatile binder and printed, or a chemical vapor deposition (CVD) method is used. Various methods such as thermal spraying, sputtering, and vapor deposition are conceivable.
このように種々の方法が考えられるが、本発明においては、同時スパッタリング法または同時蒸着法を用いることが好ましい。これらの方法では、原子あるいはクラスターレベルで、飛来した物質が基板に付着して薄膜を形成していく。そのため、粒度が微細であり、かつ、均一に分散した薄膜を、再現性よく、容易に得ることができる。また、ターゲットや蒸着源に投入する電力を変えることにより、合金組成を容易に変えることができ、すなわち、最終的に得られる多孔質層の空隙率を、容易に調整することができる。 Various methods are conceivable as described above. In the present invention, it is preferable to use a co-sputtering method or a co-evaporation method. In these methods, the flying material adheres to the substrate at the atomic or cluster level to form a thin film. Therefore, a thin film having a fine particle size and uniformly dispersed can be easily obtained with good reproducibility. Further, the alloy composition can be easily changed by changing the electric power supplied to the target and the evaporation source, that is, the porosity of the porous layer finally obtained can be easily adjusted.
異相成分としては、ＴａおよびＴａ合金、または、ＮｂおよびＮｂ合金に溶解しない金属、または酸化物を使用することが好ましい。例えば、金属成分としては、ＣｕまたはＡｇが好ましい。ＣｕまたはＡｇは、Ｔａ、Ｔａ合金、ＮｂおよびＮｂ合金に、ほとんど溶解しない。また、Ｍｇ、Ｃａ、またはこれらの酸化物も好ましい。ＭｇおよびＣａは、Ｔａ、Ｔａ合金、Ｎｂ、およびＮｂ合金に、ほとんど溶解せず、これらの酸化物は、Ｔａの酸化物や、Ｎｂの酸化物よりも、熱力学的に安定である。 As the heterogeneous component, it is preferable to use Ta and Ta alloy, or a metal or oxide that does not dissolve in Nb and Nb alloy. For example, the metal component is preferably Cu or Ag. Cu or Ag hardly dissolves in Ta, Ta alloy, Nb and Nb alloy. Moreover, Mg, Ca, or these oxides are also preferable. Mg and Ca hardly dissolve in Ta, Ta alloy, Nb, and Nb alloy, and these oxides are more thermodynamically stable than Ta oxide and Nb oxide.
［３］真空熱処理をすることにより、ＴａまたはＴａ合金（ＮｂまたはＮｂ合金）、および、異相成分を粒成長させる第３工程：
ＴａまたはＮｂを粒成長させないと、多孔質層の一体性が確保できず、また、異相成分を粒成長させて、連続化させることにより、異相成分の溶解除去が可能になる。
[3] Third step of grain growth of Ta or Ta alloy (Nb or Nb alloy) and heterogeneous components by vacuum heat treatment:
Unless Ta or Nb is grain-grown, the integrity of the porous layer cannot be secured, and the different-phase component can be dissolved and removed by growing the different-phase ingredient and making it continuous.
一般に、高温で熱処理をするほど、粒成長が進行し、最終的に得られる多孔質層の構造が粗くなる。粒成長をさせる熱処理温度としては、２００℃以上、６７０℃以下にすることが好ましい。２００℃以上とする理由は、熱処理温度が低いほど、粒成長が起こりにくくなり、かつ、得られる多孔質層の表面積が大きくなるが、低くなりすぎると、多孔質層の構造の一体性が無くなり、連続体にならないことにある。６７０℃以下とする理由は、基材の融点以上に熱処理温度を上げることができないことにある。 In general, as the heat treatment is performed at a higher temperature, grain growth proceeds and the structure of the finally obtained porous layer becomes rougher. The heat treatment temperature for grain growth is preferably 200 ° C. or higher and 670 ° C. or lower. The reason why the temperature is 200 ° C. or higher is that the lower the heat treatment temperature, the less likely the grain growth occurs, and the surface area of the resulting porous layer increases, but if it is too low, the integrity of the structure of the porous layer is lost. , Not to be a continuum. The reason why the temperature is 670 ° C. or lower is that the heat treatment temperature cannot be raised above the melting point of the substrate.
なお、スパッタリングや真空蒸着法を行なう場合は、基板を加熱しながら、合金膜形成を行なうことにより、膜形成と同時に粒成長を行なうことができる。 In the case of performing sputtering or vacuum vapor deposition, grain growth can be performed simultaneously with film formation by forming an alloy film while heating the substrate.
［４］異相成分を選択的に溶解除去する第４工程：
前述したように、熱処理で粒調整した後、異相成分の除去を行なう。除去方法として、種々の方法を用いることができるが、操作の簡便さから、電極箔の構成成分であるＴａ、Ｔａ合金、Ｎｂ、Ｎｂ合金、Ａｌ箔、または、Ａｌ合金箔と、異相成分との耐食性の差を利用して、酸で溶解除去することが好ましい。酸には、異相成分を選択的に溶解する酸を選択する。例えば、硝酸、過酸化水素を添加した硫酸や塩酸などを使用することができる。異相成分を除去した後、水洗し、乾燥して、バルブ金属複合電極箔が得られる。
[4] Fourth step of selectively dissolving and removing heterogeneous components:
As described above, after the grains are adjusted by heat treatment, the heterogeneous components are removed. Various methods can be used as a removal method. From the simplicity of operation, Ta, Ta alloy, Nb, Nb alloy, Al foil, or Al alloy foil, which is a constituent component of the electrode foil, It is preferable to dissolve and remove with an acid utilizing the difference in corrosion resistance. As the acid, an acid that selectively dissolves the heterogeneous component is selected. For example, sulfuric acid or hydrochloric acid to which nitric acid or hydrogen peroxide is added can be used. After removing the heterogeneous component, it is washed with water and dried to obtain a valve metal composite electrode foil.
このようにして得られたバルブ金属複合電極箔は、空隙が均一に分布し、表面積も大きい。また、陽極酸化により誘電体皮膜が形成される多孔質層が、Ｔａ、Ｔａ合金、Ｎｂ、または、Ｎｂ合金の粒子から形成されているため、従来のエッチングＡｌ箔よりも、静電容量が大きくなる。また、基材として体積抵抗率の小さいＡｌを用いているために、Ｔａ、Ｔａ合金、Ｎｂ、または、Ｎｂ合金のみで形成された電極箔よりも、電極抵抗を小さくすることができる。また、希少金属であるＴａやＮｂの使用量が少なくてすむため、より低コストで、電極箔を作製することが可能である。 The valve metal composite electrode foil thus obtained has a uniform distribution of voids and a large surface area. Further, since the porous layer on which the dielectric film is formed by anodic oxidation is formed of Ta, Ta alloy, Nb, or Nb alloy particles, the capacitance is larger than that of the conventional etching Al foil. Become. Moreover, since Al with a small volume resistivity is used as a base material, electrode resistance can be made smaller than electrode foil formed only with Ta, Ta alloy, Nb, or Nb alloy. In addition, since the amount of rare metals Ta and Nb used is small, it is possible to produce an electrode foil at a lower cost.
図３および図４に、本発明のバルブ金属複合電極箔を使用した電解コンデンサの一例を、断面図で示した。 FIG. 3 and FIG. 4 are sectional views showing an example of an electrolytic capacitor using the valve metal composite electrode foil of the present invention.
図３は、薄型固体電解コンデンサの断面模式図である。本発明によるバルブ金属複合電極箔（９）の表面に、陽極酸化処理により誘電体となるＴａまたはＮｂの酸化皮膜（１０）を形成し、その上にＭｎＯ2あるいはポリピロールやポリチオフェンなどの導電性高分子により電気伝導層（１１）を形成し、さらにその上にグラファイトおよび銀ベーストで陰極層（１２）が形成された構造になっている。薄型固体電解コンデンサの総厚みは、主に電極箔の厚みに依存するため、本発明によるバルブ金属複合電極箔の使用は薄型固体電解コンデンサの低背化に有効である。 FIG. 3 is a schematic cross-sectional view of a thin solid electrolytic capacitor. On the surface of the valve metal composite electrode foil (9) according to the present invention, a Ta or Nb oxide film (10) serving as a dielectric is formed by anodic oxidation, and a conductive material such as MnO 2 or polypyrrole or polythiophene is formed thereon. It has a structure in which an electrically conductive layer (11) is formed by molecules, and a cathode layer (12) is formed thereon by graphite and silver base. Since the total thickness of the thin solid electrolytic capacitor mainly depends on the thickness of the electrode foil, the use of the valve metal composite electrode foil according to the present invention is effective for reducing the height of the thin solid electrolytic capacitor.
図４は、積層型固体電解コンデンサの断面模式図である。図３で示した薄型固体電解コンデンサ素子（１３）を３つ積層し、各素子の陽極部および陰極部を絶縁性樹脂（１４）で電気的に絶縁した後、各素子の陽極部および陰極部をリードフレーム（１５、１６）で電気的接続、すなわち各素子を電気的に並列接続した構造になっている。各素子は誘電体成分の他に電極抵抗、すなわち等価直列抵抗を有するが、積層化により各素子の等価直列抵抗成分が並列接続され、結果的に積層素子全体の等価直列抵抗を低減することができる。また、その積層数が多いほど等価直列抵抗低減効果は大きくなる。本発明によるバルブ金属複合電極箔を使用した薄型固体電解コンデンサ素子は、従来のものに比べて薄型化が可能なため、このような素子積層化に有利である。 FIG. 4 is a schematic cross-sectional view of a multilayer solid electrolytic capacitor. Three thin solid electrolytic capacitor elements (13) shown in FIG. 3 are laminated, and the anode part and cathode part of each element are electrically insulated with an insulating resin (14), and then the anode part and cathode part of each element. Are electrically connected by lead frames (15, 16), that is, each element is electrically connected in parallel. Each element has an electrode resistance, that is, an equivalent series resistance in addition to the dielectric component. However, by stacking, the equivalent series resistance component of each element is connected in parallel, and as a result, the equivalent series resistance of the entire multilayer element can be reduced. it can. Also, the greater the number of layers, the greater the equivalent series resistance reduction effect. Since the thin solid electrolytic capacitor element using the valve metal composite electrode foil according to the present invention can be made thinner than the conventional one, it is advantageous for stacking such elements.
以下、実施例により本発明を説明する。 Hereinafter, the present invention will be described by way of examples.
（実施例１）
純度９９．９９％のＴａおよびＣｕターゲット（いずれもφ１５２．４ｍｍ、高純度化学研究所製）を用い、多元スパッタ装置（株式会社アルバック製、ＳＨ−４５０）で１０ｍｔｏｒｒ、Ａｒ雰囲気中で２０ｍｍ×２０ｍｍ×厚さ５０μｍのＡｌ箔（純度９９．９％）の一方の面に、Ｔａからなる緻密層を約１μｍ成膜し、引き続きＴａ−６０ｖｏｌ％Ｃｕの組成の膜を１０μｍ成膜した。その後、多元スパッタ装置中の中で裏返し、他方の面に、同様に、Ｔａからなる緻密層およびＴａ−６０ｖｏｌ％Ｃｕの組成の膜を成膜した。
Example 1
Using Ta and Cu targets of 99.99% purity (both φ152.4 mm, manufactured by High Purity Chemical Laboratory), multi-sputtering apparatus (manufactured by ULVAC, Inc., SH-450), 10 mtorr, 20 mm × 20 mm in Ar atmosphere X A dense layer made of Ta was formed in a thickness of about 1 μm on one surface of an Al foil (purity 99.9%) having a thickness of 50 μm, and subsequently a film having a composition of Ta-60 vol% Cu was formed in a thickness of 10 μm. Thereafter, the inside of the multi-source sputtering apparatus was turned over, and a dense layer made of Ta and a film having a composition of Ta-60 vol% Cu were similarly formed on the other surface.
得られた試料を、高温真空炉（東京真空製、ｔｕｒｂｏ−ｖａｃ）を用い、３．０×１０-3Ｐａ以下の真空中で、５００℃×１ｈｒの熱処理を行った。その後、６．７ｍｏｌ／ｌの硝酸水溶液に浸漬すると、気泡を発生しながらＣｕが溶解し始めた。硝酸水溶液中に１ｈｒ浸漬してＣｕを完全に溶解した後、水洗し、乾燥して、Ｔａ／Ａｌ複合電極箔を得た。 The obtained sample was heat-treated at 500 ° C. × 1 hr in a vacuum of 3.0 × 10 −3 Pa or less using a high-temperature vacuum furnace (Tokyo vacuum, turbo-vac). Thereafter, when immersed in a 6.7 mol / l nitric acid aqueous solution, Cu began to dissolve while generating bubbles. After 1 hour of immersion in an aqueous nitric acid solution to completely dissolve Cu, it was washed with water and dried to obtain a Ta / Al composite electrode foil.
得られたＴａ／Ａｌ複合電極箔の断面を、走査電子顕微鏡で観察したところ、厚さ５０μｍのＡｌ箔の両面に、Ｔａの緻密層１μｍと、Ｔａの多孔質層１０μｍとからなる積層構造が形成され、Ｔａ／Ａｌ複合電極箔の総厚さは、７２μｍであった。 When the cross section of the obtained Ta / Al composite electrode foil was observed with a scanning electron microscope, a laminated structure composed of a dense Ta layer of 1 μm and a Ta porous layer of 10 μm was formed on both sides of a 50 μm thick Al foil. The total thickness of the formed Ta / Al composite electrode foil was 72 μm.
得られたＴａ／Ａｌ複合電極箔を、１０ｍｍ角に切断し、スポットウエルダで直径０．２ｍｍのＮｂワイヤをリードとして取り付けた後、８０℃のリン酸水溶液中で電圧５Ｖ、時間６ｈｒの定電圧化成を行うことにより、その表面に誘電体となるＴａ2Ｏ5皮膜を形成した。 The obtained Ta / Al composite electrode foil was cut into a 10 mm square, and a Nb wire having a diameter of 0.2 mm was attached as a lead with a spot welder, and then a constant voltage of 5 V in phosphoric acid aqueous solution at 80 ° C. for 6 hours. By performing chemical conversion, a Ta 2 O 5 film serving as a dielectric was formed on the surface.
その後、３０質量％の硫酸中で、ＬＣＲメータ（Ａｇｉｌｅｎｔ製、４２６３Ｂ）を用い、印加バイアス１．５Ｖ、周波数１２０Ｈｚ、実効値１．０Ｖｒｍｓで、静電容量を測定した。測定結果を表１に示す。 Thereafter, the capacitance was measured in 30% by mass of sulfuric acid using an LCR meter (manufactured by Agilent, 4263B) with an applied bias of 1.5 V, a frequency of 120 Hz, and an effective value of 1.0 Vrms. The measurement results are shown in Table 1.
（実施例２）
純度９９．９９％のＮｂおよびＣｕターゲット（いずれもφ１５２．４ｍｍ、高純度化学研究所製）を用い、多元スパッタ装置（株式会社アルバック製、ＳＨ−４５０）で１０ｍｔｏｒｒ、Ａｒ雰囲気中で２０ｍｍ×２０ｍｍ×厚さ５０μｍのＡｌ箔（純度９９．９％）の一方の面に、Ａｒ＋５％Ｎ2雰囲気中で反応性スパッタを行い、バリア膜としてＴｉＮを０．５μｍ成膜した。その後、Ｎｂからなる緻密層を約１μｍ成膜し、引き続き、Ｎｂ−６０ｖｏｌ％Ｃｕの組成の膜を１０μｍ成膜した。その後、多元スパッタ装置の中で裏返し、他方の面に、同様に、バリア層、Ｎｂからなる緻密層およびＮｂ−６０ｖｏｌ％Ｃｕの組成の膜を成膜した。
(Example 2)
Using Nb and Cu targets with a purity of 99.99% (both φ152.4 mm, manufactured by High Purity Chemical Laboratory), 10 mtorr in a multi-source sputtering apparatus (manufactured by ULVAC, Inc., SH-450), 20 mm × 20 mm in an Ar atmosphere X Reactive sputtering was performed on one surface of an Al foil (purity 99.9%) having a thickness of 50 μm in an Ar + 5% N 2 atmosphere to form a TiN film having a thickness of 0.5 μm as a barrier film. Thereafter, a dense layer made of Nb was formed to a thickness of about 1 μm, and subsequently a film having a composition of Nb-60 vol% Cu was formed to a thickness of 10 μm. Thereafter, the inside of the multi-source sputtering apparatus was turned over, and similarly, a barrier layer, a dense layer made of Nb, and a film having a composition of Nb-60 vol% Cu were formed on the other surface.
得られた試料を、高温真空炉（東京真空製、ｔｕｒｂｏ−ｖａｃ）を用い、３．０×１０-3Ｐａ以下の真空中で、６００℃×１ｈｒの熱処理を行った。その後、６．７ｍｏｌ／ｌの硝酸水溶液に浸漬すると、気泡を発生しながらＣｕが溶解し始めた。硝酸水溶液中に１ｈｒ浸漬してＣｕを完全に溶解した後、水洗し、乾燥して、Ｎｂ／Ａｌ複合電極箔を得た。 The obtained sample was heat-treated at 600 ° C. × 1 hr in a vacuum of 3.0 × 10 −3 Pa or less using a high-temperature vacuum furnace (manufactured by Tokyo Vacuum, turbo-vac). Then, when immersed in a 6.7 mol / l nitric acid aqueous solution, Cu began to dissolve while generating bubbles. After 1 hour of immersion in an aqueous nitric acid solution to completely dissolve Cu, it was washed with water and dried to obtain an Nb / Al composite electrode foil.
得られたＮｂ／Ａｌ複合電極箔の断面を、走査電子顕微鏡で観察したところ、厚さ５０μｍのＡｌ箔の両面に、ＴｉＮのバリア層０．５μｍと、Ｎｂの緻密層１μｍと、Ｎｂの多孔質層１０μｍとからなる積層構造が形成され、Ｎｂ／Ａｌ複合電極箔の総厚さは、７３μｍであった。 When the cross section of the obtained Nb / Al composite electrode foil was observed with a scanning electron microscope, a TiN barrier layer of 0.5 μm, a dense Nb layer of 1 μm, and a porous Nb layer were formed on both sides of the 50 μm thick Al foil. A laminated structure composed of a porous layer of 10 μm was formed, and the total thickness of the Nb / Al composite electrode foil was 73 μm.
得られたＮｂ／Ａｌ複合電極箔を、１０ｍｍ角に切断し、スポットウエルダで直径０．２ｍｍのＮｂワイヤをリードとして取り付けた後、８０℃のリン酸水溶液中で電圧１０Ｖ、時間６ｈｒの定電圧化成を行うことにより、その表面に誘電体となるＮｂ2Ｏ5皮膜を形成した。 The obtained Nb / Al composite electrode foil was cut into a 10 mm square, and a Nb wire having a diameter of 0.2 mm was attached as a lead with a spot welder, and then a constant voltage of 10 V in phosphoric acid aqueous solution at 80 ° C. for 6 hours. By performing chemical conversion, an Nb 2 O 5 film serving as a dielectric was formed on the surface.
その後、３０質量％の硫酸中で、ＬＣＲメータ（Ａｇｉｌｅｎｔ製、４２６３Ｂ）を用い、印加バイアス１．５Ｖ、周波数１２０Ｈｚ、実効値１．０Ｖｒｍｓで、静電容量を測定した。測定結果を表１に示す。 Thereafter, the capacitance was measured in 30% by mass of sulfuric acid using an LCR meter (manufactured by Agilent, 4263B) with an applied bias of 1.5 V, a frequency of 120 Hz, and an effective value of 1.0 Vrms. The measurement results are shown in Table 1.
（実施例３）
Ｎｂの多孔質層の厚さが、２９μｍとなるようにした以外は、実施例２と同様に、Ｎｂ／Ａｌ複合電極箔を得た。
(Example 3)
An Nb / Al composite electrode foil was obtained in the same manner as in Example 2 except that the thickness of the Nb porous layer was 29 μm.
得られたＮｂ／Ａｌ複合電極箔の総厚さは、１１１μｍであった。 The total thickness of the obtained Nb / Al composite electrode foil was 111 μm.
その後、実施例２と同様に、その表面に誘電体となるＮｂ2Ｏ5皮膜を形成し、実施例２と同様にして静電容量を測定した。結果を表１に示す。 Thereafter, an Nb 2 O 5 film serving as a dielectric was formed on the surface in the same manner as in Example 2, and the capacitance was measured in the same manner as in Example 2. The results are shown in Table 1.
（実施例４）
純度９９．９９％のＴａおよびＣｕターゲット（いずれもφ１５２．４ｍｍ、高純度化学研究所製）を用い、多元スパッタ装置（株式会社アルバック製、ＳＨ−４５０）で１０ｍｔｏｒｒ、Ａｒ雰囲気中で２０ｍｍ×２０ｍｍ×厚さ５０μｍのＡｌ箔（純度９９．９％）の一方の面に、Ａｒ＋５％Ｎ2雰囲気中で反応性スパッタを行い、バリア膜としてＴｉＮを０．５μｍ成膜した。その後、Ｔａからなる緻密層を約１μｍ成膜し、引き続き、Ｔａ−６０ｖｏｌ％Ｃｕの組成の膜を１０μｍ成膜した。その後、多元スパッタ装置の中で裏返し、他方の面に、同様に、バリア層、Ｔａからなる緻密層およびＴａ−６０ｖｏｌ％Ｃｕの組成の膜を成膜した。
Example 4
Using Ta and Cu targets of 99.99% purity (both φ152.4 mm, manufactured by High Purity Chemical Laboratory), multi-sputtering apparatus (manufactured by ULVAC, Inc., SH-450), 10 mtorr, 20 mm × 20 mm in Ar atmosphere X Reactive sputtering was performed on one surface of an Al foil (purity 99.9%) having a thickness of 50 μm in an Ar + 5% N 2 atmosphere to form a TiN film having a thickness of 0.5 μm as a barrier film. Thereafter, a dense layer made of Ta was formed to a thickness of about 1 μm, and subsequently a film having a composition of Ta-60 vol% Cu was formed to a thickness of 10 μm. Thereafter, the inside of the multi-source sputtering apparatus was turned over, and a barrier layer, a dense layer made of Ta, and a film having a composition of Ta-60 vol% Cu were similarly formed on the other surface.
得られた試料を、高温真空炉（東京真空製、ｔｕｒｂｏ−ｖａｃ）を用い、３．０×１０-3Ｐａ以下の真空中で、６００℃×１ｈｒの熱処理を行った。その後、６．７ｍｏｌ／ｌの硝酸水溶液に浸漬すると、気泡を発生しながらＣｕが溶解し始めた。硝酸水溶液中に１ｈｒ浸漬してＣｕを完全に溶解した後、水洗し、乾燥して、Ｔａ／Ａｌ複合電極箔を得た。 The obtained sample was heat-treated at 600 ° C. × 1 hr in a vacuum of 3.0 × 10 −3 Pa or less using a high-temperature vacuum furnace (manufactured by Tokyo Vacuum, turbo-vac). Then, when immersed in a 6.7 mol / l nitric acid aqueous solution, Cu began to dissolve while generating bubbles. After 1 hour of immersion in an aqueous nitric acid solution to completely dissolve Cu, it was washed with water and dried to obtain a Ta / Al composite electrode foil.
得られたＴａ／Ａｌ複合電極箔の断面を、走査電子顕微鏡で観察したところ、厚さ５０μｍのＡｌ箔の両面に、ＴｉＮのバリア層０．５μｍと、Ｔａの緻密層１μｍと、Ｔａの多孔質層１０μｍとからなる積層構造が形成され、Ｔａ／Ａｌ複合電極箔の総厚さは、７３μｍであった。 When a cross section of the obtained Ta / Al composite electrode foil was observed with a scanning electron microscope, a TiN barrier layer of 0.5 μm, a Ta dense layer of 1 μm, and a porous Ta layer were formed on both sides of a 50 μm thick Al foil. A laminated structure composed of a porous layer of 10 μm was formed, and the total thickness of the Ta / Al composite electrode foil was 73 μm.
その後、実施例１と同様に、その表面に誘電体となるＴａ2Ｏ5皮膜を形成し、実施例１と同様にして静電容量を測定した。結果を表１に示す。 Thereafter, a Ta 2 O 5 film serving as a dielectric was formed on the surface in the same manner as in Example 1, and the capacitance was measured in the same manner as in Example 1. The results are shown in Table 1.
（比較例１）
高温真空炉（東京真空製、ｔｕｒｂｏ−ｖａｃ）において、３．０×１０-3Ｐａ以下の真空中で、１８０℃×２ｈｒの熱処理を行ったこと以外は、実施例１と同様に成膜を行った後、６．７ｍｏｌ／ｌの硝酸水溶液に１ｈｒ浸漬したが、気泡は発生せず、Ｃｕは溶解しなかった。その後、水洗し、乾燥して、得られた試料の断面を走査電子顕微鏡で観察したが、全体が緻密層であり、多孔質層は確認されなかった。
(Comparative Example 1)
Film formation was performed in the same manner as in Example 1 except that heat treatment was performed at 180 ° C. for 2 hours in a vacuum of 3.0 × 10 −3 Pa or less in a high-temperature vacuum furnace (manufactured by Tokyo Vacuum, turbo-vac). After performing, it was immersed in a 6.7 mol / l nitric acid aqueous solution for 1 hr, but no bubbles were generated and Cu was not dissolved. Thereafter, it was washed with water and dried, and the cross section of the obtained sample was observed with a scanning electron microscope, but the whole was a dense layer, and no porous layer was confirmed.
（比較例２）
Ｔａ−６０ｖｏｌ％Ｃｕの組成であった膜を、Ｔａ−７５ｖｏｌ％Ｃｕの組成の膜としたこと以外は、実施例１と同様に成膜を行った後、６．７ｍｏｌ／ｌの硝酸水溶液に１ｈｒ浸漬したところ、溶解中、表面から黒い繊維状の離脱物が観察された。その後、水洗し、乾燥して、得られた試料の断面を走査電子顕微鏡で観察した。
(Comparative Example 2)
A film having a composition of Ta-60 vol% Cu was formed in the same manner as in Example 1 except that the film having a composition of Ta-75 vol% Cu was used, and then a 6.7 mol / l nitric acid aqueous solution was added. When immersed for 1 hr, black fibrous detachment was observed from the surface during dissolution. Thereafter, the sample was washed with water and dried, and the cross section of the obtained sample was observed with a scanning electron microscope.
得られたＴａ／Ａｌ複合電極箔の断面を、走査電子顕微鏡で観察したところ、厚さ５０μｍのＡｌ箔の両面に、Ｔａの緻密層１μｍと、Ｔａの多孔質層とからなる積層構造が形成されていたが、多孔質層は完全な連続体とはならず、ところどころで剥離が発生していた。 When the cross section of the obtained Ta / Al composite electrode foil was observed with a scanning electron microscope, a laminated structure consisting of a 1 μm thick Ta layer and a porous Ta layer was formed on both sides of the 50 μm thick Al foil. However, the porous layer did not become a complete continuum, and peeling occurred in some places.
（比較例３）
純度９９．９９％のＴａおよびＣｕターゲット（いずれもφ１５２．４ｍｍ、高純度化学研究所製）を用い、多元スパッタ装置（株式会社アルバック製、ＳＨ−４５０）で１０ｍｔｏｒｒ、Ａｒ雰囲気中で２０ｍｍ×２０ｍｍ×厚さ１１０μｍのＡｌ箔（純度９９．９％）の一方の面に、Ｔａからなる緻密層を約１μｍ成膜し、引き続きＴａ−６０ｖｏｌ％Ｃｕの組成の膜を５μｍ成膜した。その後、多元スパッタ装置中の中で裏返し、他方の面に、同様に、Ｔａからなる緻密層およびＴａ−６０ｖｏｌ％Ｃｕの組成の膜を成膜した。
(Comparative Example 3)
Using Ta and Cu targets of 99.99% purity (both φ152.4 mm, manufactured by High Purity Chemical Laboratory), multi-sputtering apparatus (manufactured by ULVAC, Inc., SH-450), 10 mtorr, 20 mm × 20 mm in Ar atmosphere X A dense layer made of Ta was formed in a thickness of about 1 μm on one surface of a 110 μm thick Al foil (purity 99.9%), and subsequently a film having a composition of Ta-60 vol% Cu was formed in a thickness of 5 μm. Thereafter, the inside of the multi-source sputtering apparatus was turned over, and a dense layer made of Ta and a film having a composition of Ta-60 vol% Cu were similarly formed on the other surface.
得られた試料を、高温真空炉（東京真空製、ｔｕｒｂｏ−ｖａｃ）を用い、３．０×１０-3Ｐａ以下の真空中で、５００℃×１ｈｒの熱処理を行った。その後、６．７ｍｏｌ／ｌの硝酸水溶液に浸漬すると、気泡を発生しながらＣｕが溶解し始めた。硝酸水溶液中に１ｈｒ浸漬してＣｕを完全に溶解した後、水洗し、乾燥して、Ｔａ／Ａｌ複合電極箔を得た。 The obtained sample was heat-treated at 500 ° C. × 1 hr in a vacuum of 3.0 × 10 −3 Pa or less using a high-temperature vacuum furnace (Tokyo vacuum, turbo-vac). Thereafter, when immersed in a 6.7 mol / l nitric acid aqueous solution, Cu began to dissolve while generating bubbles. After 1 hour of immersion in an aqueous nitric acid solution to completely dissolve Cu, it was washed with water and dried to obtain a Ta / Al composite electrode foil.
得られたＴａ／Ａｌ複合電極箔の断面を、走査電子顕微鏡で観察したところ、厚さ１１０μｍのＡｌ箔の両面に、Ｔａの緻密層１μｍと、Ｔａの多孔質層５μｍとからなる積層構造が形成され、Ｔａ／Ａｌ複合電極箔の総厚さは、１２２μｍであった。 When a cross section of the obtained Ta / Al composite electrode foil was observed with a scanning electron microscope, a laminated structure composed of a dense Ta layer of 1 μm and a Ta porous layer of 5 μm was formed on both sides of an Al foil having a thickness of 110 μm. The total thickness of the formed Ta / Al composite electrode foil was 122 μm.
その後、実施例１と同様に、その表面に誘電体となるＴａ2Ｏ5皮膜を形成し、実施例１と同様にして静電容量を測定した。結果を表１に示す。 Thereafter, a Ta 2 O 5 film serving as a dielectric was formed on the surface in the same manner as in Example 1, and the capacitance was measured in the same manner as in Example 1. The results are shown in Table 1.
（従来例１）
厚さが約３０μｍである基材と、両面に厚さが約４０μｍであるエッチング層とからなり、総厚さが１１０μｍである交流エッチングＡｌ箔を、１０ｃｍ角に切断し、直径０．２ｍｍのＮｂワイヤをリードとして取り付けた後、８５℃のほう酸アンモニウム水溶液中で電圧５Ｖ、時間６ｈｒの陽極酸化処理を行うことにより、その表面に誘電体となるＡｌ2Ｏ3皮膜を形成した。
(Conventional example 1)
An AC-etched Al foil having a total thickness of 110 μm consisting of a base material having a thickness of about 30 μm and an etching layer having a thickness of about 40 μm on both sides is cut into 10 cm square and has a diameter of 0.2 mm. After attaching the Nb wire as a lead, an anodization treatment was performed in an aqueous solution of ammonium borate at 85 ° C. for 5 hours at a voltage of 6 hours, thereby forming an Al 2 O 3 film serving as a dielectric on the surface.
得られた試料について、３０質量％の硫酸中で、ＬＣＲメータ（Ａｇｉｌｅｎｔ製、４２６３Ｂ）を用い、印加バイアス１．５Ｖ、周波数１２０Ｈｚ、実効値１．０Ｖｒｍｓで、静電容量を測定した。測定結果を表１に示す。 The obtained sample was measured for its capacitance in 30% by mass sulfuric acid using an LCR meter (manufactured by Agilent, 4263B) at an applied bias of 1.5 V, a frequency of 120 Hz, and an effective value of 1.0 Vrms. The measurement results are shown in Table 1.
（従来例２）
陽極酸化処理の電圧を１０Ｖとしたこと以外は、従来例１と同様に、試料を得て、静電容量を測定した。結果を表１に示す。
(Conventional example 2)
A sample was obtained and the capacitance was measured in the same manner as in Conventional Example 1 except that the anodizing voltage was 10 V. The results are shown in Table 1.
（従来例３）
純度９９．９９％のＴａおよびＣｕターゲット（いずれもφ１５２．４ｍｍ、高純度化学研究所製）を用い、多元スパッタ装置（株式会社アルバック製、ＳＨ−４５０）で１０ｍｔｏｒｒ、Ａｒ雰囲気中で２０ｍｍ×２０ｍｍ×厚さ５０μｍのＴａ箔（東京電解株式会社製、純度９９．９％以上）の両面に、Ｔａ−６０ｖｏｌ％Ｃｕを厚さ１０μｍずつ成膜した。得られた試料を、高温真空炉（東京真空製、ｔｕｒｂｏ−ｖａｃ）を用い、３．０×１０-3Ｐａ以下の真空中で、５００℃×１ｈｒの熱処理を行った。その後、６．７ｍｏｌ／ｌの硝酸水溶液中に１ｈｒ浸漬してＣｕを完全に溶解した後、水洗し、乾燥して、Ｔａ電極箔を得た。
(Conventional example 3)
Using Ta and Cu targets of 99.99% purity (both φ152.4 mm, manufactured by High Purity Chemical Laboratory), multi-sputtering apparatus (manufactured by ULVAC, Inc., SH-450), 10 mtorr, 20 mm × 20 mm in Ar atmosphere × Ta-60 vol% Cu was deposited in a thickness of 10 μm on both sides of a 50 μm thick Ta foil (manufactured by Tokyo Electrolytic Co., Ltd., purity 99.9% or more). The obtained sample was heat-treated at 500 ° C. × 1 hr in a vacuum of 3.0 × 10 −3 Pa or less using a high-temperature vacuum furnace (Tokyo vacuum, turbo-vac). Thereafter, Cu was completely dissolved by immersing in a 6.7 mol / l nitric acid aqueous solution for 1 hour, and then washed with water and dried to obtain a Ta electrode foil.
得られたＴａ電極箔の断面を、走査電子顕微鏡で観察したところ、厚さ５０μｍのＴａ箔の両面に、Ｔａの多孔質層１０μｍが形成されており、Ｔａ電極箔の総厚さは７０μｍであった。 When the cross section of the obtained Ta electrode foil was observed with a scanning electron microscope, a Ta porous layer of 10 μm was formed on both sides of the 50 μm thick Ta foil, and the total thickness of the Ta electrode foil was 70 μm. there were.
その後、実施例１と同様に、その表面に誘電体となるＴａ2Ｏ5皮膜を形成し、実施例１と同様にして静電容量を測定した。結果を表１に示す。 Thereafter, a Ta 2 O 5 film serving as a dielectric was formed on the surface in the same manner as in Example 1, and the capacitance was measured in the same manner as in Example 1. The results are shown in Table 1.
陽極酸化電圧が同じ実施例１と従来例１、および陽極酸化電圧が同じ実施例２、３、４と従来例２において、それぞれの面積静電容量密度の比較から、本発明のバルブ金属複合電極箔は、従来の交流エッチングＡｌ箔に対して、数倍の面積静電容量密度が得られ、コンデンサの小型化および大容量化に有利であることが分かる。 In Example 1 and Conventional Example 1 having the same anodic oxidation voltage, and in Examples 2, 3, 4 and Conventional Example 2 having the same anodic oxidation voltage, the valve metal composite electrode of the present invention was compared based on the comparison of the area capacitance density. It can be seen that the foil has an area capacitance density several times that of the conventional AC-etched Al foil, and is advantageous in reducing the size and capacity of the capacitor.
また、熱処理温度が低い比較例１では、多孔質層が得られず、成膜組成が本発明の範囲外である比較例２では、多孔質化したものの、剥離が発生してしまった。 Further, in Comparative Example 1 where the heat treatment temperature was low, a porous layer was not obtained, and in Comparative Example 2 where the film-forming composition was outside the scope of the present invention, although it was made porous, peeling occurred.
また、基材に１１０μｍのＡｌ箔を使用した比較例３では、従来の交流エッチングＡｌ箔と同等の面積静電容量密度となって、大容量化が得られなかった。 In Comparative Example 3 in which a 110 μm Al foil was used as the base material, the area capacitance density was the same as that of the conventional AC-etched Al foil, and a large capacity could not be obtained.
実施例１と従来例３の比較から、Ａｌ箔基板を用いても、従来のＴａ箔基板を用いたものと同等の面積静電容量密度を得られることが確認された。基板として、希少であり体積抵抗率が比較的大きいＴａの代わりに、安価であり低抵抗であるＡｌを用いることが可能であることが示された。 From the comparison between Example 1 and Conventional Example 3, it was confirmed that even if an Al foil substrate was used, an area capacitance density equivalent to that using a conventional Ta foil substrate could be obtained. It was shown that it is possible to use Al which is inexpensive and has low resistance, instead of Ta, which is rare and has a relatively large volume resistivity.
（実施例５）
実施例３で得られたＮｂ／Ａｌ複合電極箔に、８０℃のリン酸水溶液中で電圧１０Ｖ、時間６ｈｒの陽極酸化処理を施して、その表面に誘電体となるＮｂ2Ｏ5皮膜を形成した。得られた試料に、化学重合でポリピロールを形成し、ついでカーボンペーストとＡｇペーストを塗布して、薄型固体電解コンデンサを作製した。コンデンサ断面構造は、厚さが１１０μｍのＮｂ／Ａｌ複合電極箔の両面に、ポリピロール層１５μｍ、カーボンペーストおよびＡｇペースト層３０μｍが形成された構造になっており、総厚さは約２００μｍであった。
(Example 5)
The Nb / Al composite electrode foil obtained in Example 3 was anodized in a phosphoric acid aqueous solution at 80 ° C. for 10 hours and for 6 hours to form an Nb 2 O 5 film serving as a dielectric on the surface. did. Polypyrrole was formed on the obtained sample by chemical polymerization, and then a carbon paste and an Ag paste were applied to produce a thin solid electrolytic capacitor. The capacitor cross-sectional structure has a structure in which a polypyrrole layer 15 μm, a carbon paste and an Ag paste layer 30 μm are formed on both surfaces of a 110 μm thick Nb / Al composite electrode foil, and the total thickness is about 200 μm. .
得られた固体電解コンデンサについて、ＬＣＲメータ（Ａｇｉｌｅｎｔ製、４２６３Ｂ）を用い、印加バイアス１．５Ｖ、周波数１２０Ｈｚ、実効値１．０Ｖｒｍｓで、静電容量を測定した。測定結果を表２に示す。 About the obtained solid electrolytic capacitor, the electrostatic capacitance was measured by the applied bias 1.5V, the frequency 120Hz, and the effective value 1.0Vrms using the LCR meter (The product made from Agilent, 4263B). The measurement results are shown in Table 2.
（実施例６）
実施例２で得られたＮｂ／Ａｌ複合電極箔に、８０℃のリン酸水溶液中で電圧１０Ｖ、時間６ｈｒの陽極酸化処理を施して、その表面に誘電体となるＮｂ2Ｏ5皮膜を形成した。得られた試料に、化学重合でポリピロールを形成し、ついでカーボンペーストとＡｇペーストを塗布して、薄型固体電解コンデンサを作製した。コンデンサ断面構造は、厚さが７２μｍのＮｂ／Ａｌ複合電極箔の両面に、ポリピロール層１５μｍ、カーボンペーストおよびＡｇペースト層３０μｍが形成された構造になっており、総厚さは約１６２μｍであった。
(Example 6)
The Nb / Al composite electrode foil obtained in Example 2 was anodized in a phosphoric acid aqueous solution at 80 ° C. for 10 hours and for 6 hours to form a Nb 2 O 5 film serving as a dielectric on the surface. did. Polypyrrole was formed on the obtained sample by chemical polymerization, and then a carbon paste and an Ag paste were applied to produce a thin solid electrolytic capacitor. The capacitor cross-sectional structure has a structure in which a polypyrrole layer 15 μm, a carbon paste and an Ag paste layer 30 μm are formed on both surfaces of a 72 μm thick Nb / Al composite electrode foil, and the total thickness is about 162 μm. .
得られた固体電解コンデンサについて、ＬＣＲメータ（Ａｇｉｌｅｎｔ製、４２６３Ｂ）を用い、印加バイアス１．５Ｖ、周波数１２０Ｈｚ、実効値１．０Ｖｒｍｓで、静電容量を測定した。測定結果を表２に示す。 About the obtained solid electrolytic capacitor, the electrostatic capacitance was measured by the applied bias 1.5V, the frequency 120Hz, and the effective value 1.0Vrms using the LCR meter (The product made from Agilent, 4263B). The measurement results are shown in Table 2.
（比較例４）
厚さが約３０μｍである基材と、両面に厚さが約４０μｍであるエッチング層とからなり、総厚さが１１０μｍである交流エッチングＡｌ箔に、８５℃のほう酸アンモニウム水溶液中で電圧１０Ｖ、時間６ｈｒの陽極酸化処理を施して、その表面に誘電体となるＡｌ2Ｏ3皮膜を形成した。得られた試料に、化学重合でポリピロールを形成し、ついでカーボンペーストとＡｇペーストを塗布して、薄型固体電解コンデンサを作製した。コンデンサ断面構造は、厚さが１１０μｍの交流エッチングＡｌ箔の両面に、ポリピロール層１５μｍ、カーボンペーストおよびＡｇペースト層３０μｍが形成された構造になっており、総厚さは約２００μｍであった。
(Comparative Example 4)
A voltage of 10V in an aqueous solution of ammonium borate at 85 ° C. was formed on an AC-etched Al foil consisting of a substrate having a thickness of about 30 μm and an etching layer having a thickness of about 40 μm on both sides and a total thickness of 110 μm. An anodizing treatment for 6 hours was performed, and an Al 2 O 3 film serving as a dielectric was formed on the surface. Polypyrrole was formed on the obtained sample by chemical polymerization, and then a carbon paste and an Ag paste were applied to produce a thin solid electrolytic capacitor. The capacitor cross-sectional structure was such that a polypyrrole layer 15 μm, a carbon paste and an Ag paste layer 30 μm were formed on both surfaces of an AC-etched Al foil having a thickness of 110 μm, and the total thickness was about 200 μm.
得られた固体電解コンデンサについて、ＬＣＲメータ（Ａｇｉｌｅｎｔ製、４２６３Ｂ）を用い、印加バイアス１．５Ｖ、周波数１２０Ｈｚ、実効値１．０Ｖｒｍｓで、静電容量を測定した。測定結果を表２に示す。 About the obtained solid electrolytic capacitor, the electrostatic capacitance was measured by the applied bias 1.5V, the frequency 120Hz, and the effective value 1.0Vrms using the LCR meter (The product made from Agilent, 4263B). The measurement results are shown in Table 2.
実施例５と比較例４の比較から、本発明の複合電極箔を使用することで、従来と同じ厚さで面積静電容量密度を数倍高められることが分かる。また、実施例６は比較例４よりも厚さが薄いにもかかわらず、２倍以上の静電容量密度が得られている。このことから、本発明により、より薄型大容量の固体電解コンデンサが作製可能なことが分かる。また、コンデンサ素子を薄型化できることにより、同じ厚さでより多くの素子の積層化が可能になる。これは、静電容量密度の向上とコンデンサのＥＳＲ低減につながるため、本発明のバルブ金属複合電極箔を使用した固体電解コンデンサは、積層型固体電解コンデンサの素子として有用である。 From the comparison between Example 5 and Comparative Example 4, it can be seen that by using the composite electrode foil of the present invention, the area capacitance density can be increased several times with the same thickness as the conventional one. In addition, although Example 6 is thinner than Comparative Example 4, a capacitance density that is twice or more is obtained. From this, it can be seen that a thinner and larger capacity solid electrolytic capacitor can be produced by the present invention. Further, since the capacitor element can be thinned, more elements can be stacked with the same thickness. This leads to an improvement in capacitance density and a reduction in ESR of the capacitor. Therefore, the solid electrolytic capacitor using the valve metal composite electrode foil of the present invention is useful as an element of a multilayer solid electrolytic capacitor.
以上、説明したように、本発明のバルブ金属複合電極箔は、従来のエッチングＡｌ箔の数倍の静電容量密度を有し、かつ、Ｔａ単体およびＮｂ単体の電極箔に比較して、電極抵抗が低くなる。また、基材としてＡｌを使用しており、希少金属であるＴａおよびＮｂを単体で使用した電極箔に比較して、低コストで電極箔を作製することが可能になるため、電解コンデンサ用の電極箔として有用である。 As described above, the valve metal composite electrode foil of the present invention has a capacitance density several times that of the conventional etching Al foil, and is an electrode as compared with the electrode foil of Ta alone and Nb alone. Resistance becomes low. Moreover, since Al is used as a base material, and it becomes possible to produce an electrode foil at a low cost compared to an electrode foil using rare metals Ta and Nb alone, it is possible to use for an electrolytic capacitor. It is useful as an electrode foil.
１ 多孔質ペレット
２ ワイヤ
３ 基材
４ 多孔質層
５ 基材
６ 緻密層
７ 多孔質層
８ バリア層
９ バルブ金属複合電極箔
１０ 酸化皮膜
１１ 電気伝導層
１２ 陰極層
１３ 固体電解コンデンサ素子
１４ 絶縁層
１５ 陽極リードフレーム
１６ 陰極リードフレーム
DESCRIPTION OF SYMBOLS 1 Porous pellet 2 Wire 3 Base material 4 Porous layer 5 Base material 6 Dense layer 7 Porous layer 8 Barrier layer 9 Valve metal composite electrode foil 10 Oxide film 11 Electrically conductive layer 12 Cathode layer 13 Solid electrolytic capacitor element 14 Insulating layer 15 Anode lead frame 16 Cathode lead frame
Claims (19)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2006191194A JP4665854B2 (en) | 2006-07-12 | 2006-07-12 | Valve metal composite electrode foil and manufacturing method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2006191194A JP4665854B2 (en) | 2006-07-12 | 2006-07-12 | Valve metal composite electrode foil and manufacturing method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2008021761A JP2008021761A (en) | 2008-01-31 |
| JP4665854B2 true JP4665854B2 (en) | 2011-04-06 |
Family
ID=39077531
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2006191194A Active JP4665854B2 (en) | 2006-07-12 | 2006-07-12 | Valve metal composite electrode foil and manufacturing method thereof |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4665854B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4985582B2 (en) * | 2008-08-11 | 2012-07-25 | 住友金属鉱山株式会社 | Method for producing tantalum porous membrane and method for producing tantalum porous electrode foil |
| JP6528076B2 (en) * | 2014-10-09 | 2019-06-12 | パナソニックＩｐマネジメント株式会社 | Electrode foil, method of manufacturing the same, and electrolytic capacitor |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000508475A (en) * | 1996-04-09 | 2000-07-04 | ザ ボード オブ トラスティーズ オブ ザ ユニバーシティー オブ アーカンソー | Ultra wideband low impedance floating plate capacitor |
| JP2001291819A (en) * | 2000-03-07 | 2001-10-19 | Fujitsu Ltd | Multilayer interconnected module with discrete capacitor and component buried therein and its manufacturing method |
| JP2003522420A (en) * | 2000-02-03 | 2003-07-22 | ケース ウェスタン リザーブ ユニバーシティ | High power capacitors from thin layers of metal powder or metal sponge particles |
| JP2003297693A (en) * | 2002-03-29 | 2003-10-17 | Nippon Chemicon Corp | Solid electrolytic capacitor |
| JP2004134451A (en) * | 2002-10-08 | 2004-04-30 | Renesas Technology Corp | Semiconductor device and its manufacturing method |
| JP2006049816A (en) * | 2004-07-05 | 2006-02-16 | Sumitomo Metal Mining Co Ltd | Porous bulb metal film |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2757796B2 (en) * | 1994-11-10 | 1998-05-25 | 日本電気株式会社 | Semiconductor integrated circuit device |
| JP3417167B2 (en) * | 1995-09-29 | 2003-06-16 | ソニー株式会社 | Capacitor structure of semiconductor memory device and method of forming the same |
-
2006
- 2006-07-12 JP JP2006191194A patent/JP4665854B2/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000508475A (en) * | 1996-04-09 | 2000-07-04 | ザ ボード オブ トラスティーズ オブ ザ ユニバーシティー オブ アーカンソー | Ultra wideband low impedance floating plate capacitor |
| JP2003522420A (en) * | 2000-02-03 | 2003-07-22 | ケース ウェスタン リザーブ ユニバーシティ | High power capacitors from thin layers of metal powder or metal sponge particles |
| JP2001291819A (en) * | 2000-03-07 | 2001-10-19 | Fujitsu Ltd | Multilayer interconnected module with discrete capacitor and component buried therein and its manufacturing method |
| JP2003297693A (en) * | 2002-03-29 | 2003-10-17 | Nippon Chemicon Corp | Solid electrolytic capacitor |
| JP2004134451A (en) * | 2002-10-08 | 2004-04-30 | Renesas Technology Corp | Semiconductor device and its manufacturing method |
| JP2006049816A (en) * | 2004-07-05 | 2006-02-16 | Sumitomo Metal Mining Co Ltd | Porous bulb metal film |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2008021761A (en) | 2008-01-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3746627B2 (en) | Manufacturing method of high surface area foil electrode | |
| US8213159B2 (en) | Electrode foil, method of manufacturing electrode foil, and electrolytic capacitor | |
| JP4561428B2 (en) | Porous valve metal thin film, manufacturing method thereof, and thin film capacitor | |
| US8597376B2 (en) | Method of producing porous valve metal thin film and thin film produced thereby | |
| WO2009125620A1 (en) | Capacitor and method for manufacturing the same | |
| JP4665866B2 (en) | Manufacturing method of valve metal composite electrode foil | |
| JP5232899B2 (en) | Solid electrolytic capacitor | |
| JP4992522B2 (en) | Capacitor electrode foil and capacitor using the same | |
| JP4665889B2 (en) | Manufacturing method of valve metal composite electrode foil | |
| JP4553770B2 (en) | Solid electrolytic capacitor and manufacturing method thereof | |
| JP4390456B2 (en) | Electrolytic capacitor and manufacturing method thereof | |
| JP4665854B2 (en) | Valve metal composite electrode foil and manufacturing method thereof | |
| JP2008047755A (en) | Manufacturing method of valve metal composite electrode foil | |
| US20180114647A1 (en) | Capacitor and method for manufacturing the capacitor | |
| JP2008252019A (en) | Method for manufacturing thin-film capacitor | |
| JP2010114297A (en) | Multilayer porous electrode foil and method of manufacturing the same, and multilayer solid-state electrolytic capacitor using multilayer porous electrode foil | |
| JP5104008B2 (en) | Electrolytic capacitor | |
| JP5573362B2 (en) | Electrode foil, capacitor using this electrode foil, and method for producing electrode foil | |
| JP5223517B2 (en) | Foil-like porous valve metal anode body and method for producing the same | |
| JP2007305780A (en) | Metallic porous-foil anode body and its manufacturing method | |
| JP2006108626A (en) | Solid electrolytic capacitor and its manufacturing method | |
| JP4561293B2 (en) | Thin film capacitor, circuit component having thin film resistor, and manufacturing method thereof | |
| JP7259406B2 (en) | Solid electrolytic capacitor element and method for manufacturing solid electrolytic capacitor element | |
| JP2960099B2 (en) | Lead wire for tantalum capacitor | |
| JP2009170871A (en) | Porous valve metal electrode and method of manufacturing the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20081118 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20101202 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20101214 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20101227 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140121 Year of fee payment: 3 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 4665854 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 Free format text: JAPANESE INTERMEDIATE CODE: R150 |