JPS6253594B2 - - Google Patents
Info
- Publication number
- JPS6253594B2 JPS6253594B2 JP14514280A JP14514280A JPS6253594B2 JP S6253594 B2 JPS6253594 B2 JP S6253594B2 JP 14514280 A JP14514280 A JP 14514280A JP 14514280 A JP14514280 A JP 14514280A JP S6253594 B2 JPS6253594 B2 JP S6253594B2
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- tantalum
- oxide film
- counter electrode
- electrolyte
- 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.)
- Expired
Links
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 8
- 238000007743 anodising Methods 0.000 claims description 7
- 239000008151 electrolyte solution Substances 0.000 claims description 5
- 238000000034 method Methods 0.000 claims description 5
- 239000003990 capacitor Substances 0.000 description 13
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 12
- 239000010408 film Substances 0.000 description 11
- 239000003792 electrolyte Substances 0.000 description 9
- 230000015572 biosynthetic process Effects 0.000 description 8
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 6
- 229910052715 tantalum Inorganic materials 0.000 description 6
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- NUJOXMJBOLGQSY-UHFFFAOYSA-N manganese dioxide Chemical compound O=[Mn]=O NUJOXMJBOLGQSY-UHFFFAOYSA-N 0.000 description 4
- 230000003647 oxidation Effects 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- 239000010407 anodic oxide Substances 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 239000010409 thin film Substances 0.000 description 3
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- 238000002048 anodisation reaction Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- DLYUQMMRRRQYAE-UHFFFAOYSA-N tetraphosphorus decaoxide Chemical compound O1P(O2)(=O)OP3(=O)OP1(=O)OP2(=O)O3 DLYUQMMRRRQYAE-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
Description
【発明の詳細な説明】
本発明はタンタル金属の陽極酸化法に関するも
のである。タンタル固体電解コンデンサやタンタ
ル薄膜コンデンサはタンタル金属表面を電解液中
で陽極酸化して形成させた酸化皮膜を誘電体とし
て用いたコンデンサであり、電解液には希薄燐酸
水溶液や燐酸塩その他の塩を溶質とし水を溶媒と
する電解液が用いられる。陽極酸化はタンタル金
属を金属やカーボンなど導電材よりなる対極と対
向させて電解液中にともに浸漬し、タンタル金属
を陽極として対極との間に通電することにより行
なわれる。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for anodizing tantalum metal. Tantalum solid electrolytic capacitors and tantalum thin film capacitors are capacitors that use as a dielectric an oxide film formed by anodizing the tantalum metal surface in an electrolyte. An electrolytic solution with water as a solute and a solvent is used. Anodic oxidation is performed by placing tantalum metal facing a counter electrode made of a conductive material such as metal or carbon, immersing both in an electrolytic solution, and applying current between the tantalum metal and the counter electrode using the tantalum metal as an anode.
たとえば、この通電を一定電流で行なういわゆ
る定電流化成により極間電圧は時間とともに上昇
する。所望の電圧に達したのちこの電圧に保持す
る陽極酸化、いわゆる定電圧化成により、電流は
減少し、酸化膜の生成は停止に向う。陽極酸化皮
膜の形成されたタンタル金属をなるべく電導度の
良好な電解液中に陰極と対向させて浸漬すると、
この両極間にコンデンサ作用が示される。すなわ
ち、酸化皮膜を誘電体とし、その両側のタンタル
金属と電解液を電極体とするコンデンサが構成さ
れる。先に述べた化成電圧Ｖと、酸化膜誘電体の
単位面積あたりの示す静電容量Ｃとの積はCV値
（μＦ・Ｖ／cm2）と呼ばれ、化成電圧の如何に拘
わらずほゞ一定である。水を溶媒とする通常の陽
極酸化用電解液の場合、25℃で２時間の定電圧化
成ののちCV値は12.5μＦ・Ｖ／cm2である。 For example, the voltage between the electrodes increases with time due to so-called constant current formation in which current is applied at a constant current. After a desired voltage is reached, the current is reduced by anodic oxidation, so-called constant voltage anodization, in which the voltage is maintained at this voltage, and the generation of the oxide film tends to stop. When the tantalum metal with the anodic oxide film formed is immersed in an electrolytic solution with as good conductivity as possible, facing the cathode,
A capacitor action is exhibited between these two poles. That is, a capacitor is constructed in which the oxide film is used as a dielectric, and the tantalum metal and electrolyte on both sides thereof are used as electrode bodies. The product of the formation voltage V mentioned earlier and the capacitance C per unit area of the oxide film dielectric is called the CV value (μF・V/cm 2 ), and it is approximately the same regardless of the formation voltage. constant. In the case of an ordinary electrolytic solution for anodizing using water as a solvent, the CV value is 12.5 μF·V/cm 2 after constant voltage formation at 25° C. for 2 hours.
一方、コンデンサの動作電圧は化成電圧によつ
て規制され、電解液を対向極とするいわゆる湿式
電解コンデンサにおいては化成電圧の60〜70％、
二酸化マンガンを対向極とする固体電解コンデン
サでは25〜35％、金属薄膜を対向極とする薄膜コ
ンデンサにおいては、酸化皮膜の絶縁破壊回避の
ためにさらに低率の動作電圧が選ばれる。 On the other hand, the operating voltage of a capacitor is regulated by the formation voltage, and in so-called wet electrolytic capacitors in which the electrolyte is the counter electrode, the voltage is 60 to 70% of the formation voltage.
For solid electrolytic capacitors with manganese dioxide as the counter electrode, an operating voltage of 25 to 35% is selected, and in thin film capacitors with a metal thin film as the counter electrode, an even lower operating voltage is selected to avoid dielectric breakdown of the oxide film.
従来、タンタル金属の節減やコンデンサの小形
化の努力は、焼結タンタル電極の素材タンタル粉
の微細化や焼結温度の低下による表面積の拡大
や、固体コンデンサにおける二酸化マンガンの焼
付け条件の改良による酸化皮膜の絶縁劣化回避に
よる動作電圧の向上などによつて進められてき
た。 Traditionally, efforts to save tantalum metal and downsize capacitors have focused on increasing the surface area by making the tantalum powder used for sintered tantalum electrodes finer and lowering the sintering temperature, and by improving the baking conditions for manganese dioxide in solid capacitors. Progress has been made by improving the operating voltage by avoiding insulation deterioration of the film.
本発明は、酸化皮膜のCV値の増大により、タ
ンタル材料の節減とコンデンサの小形化をはかる
ことを目的としたものである。本発明における
CV値の増大は、少水分の燐酸溶液を陽極酸化用
電解液に用いることを特徴とするものである。本
発明の陽極酸化法における燐酸溶液の好適濃度範
囲は90〜99％のH3PO4と残部の水から成るもので
あり、これ以下のH3PO4濃度ではCV値の増加が
ほとんど認められず、これ以上の濃度、すなわち
水分をさらに少なくしていくとH3PO4が脱水され
た成分に移行し、このような組成領域では絶縁性
の酸化皮膜が形成されない。好適範囲においては
CV値は通常の希薄燐酸水溶液電解液よりも最高
約８％の増大が得られ、しかも、tanδおよび漏
れ電流は劣化しないという特徴がある。 The present invention aims to reduce the amount of tantalum material and downsize the capacitor by increasing the CV value of the oxide film. In the present invention
The increase in the CV value is characterized by using a phosphoric acid solution with low water content as the electrolyte for anodizing. The preferred concentration range of the phosphoric acid solution in the anodizing method of the present invention is one consisting of 90 to 99% H 3 PO 4 and the balance water; at H 3 PO 4 concentrations below this, almost no increase in the CV value is observed. First, if the concentration is higher than this, that is, if the water content is further reduced, H 3 PO 4 will shift to a dehydrated component, and an insulating oxide film will not be formed in such a composition range. In the preferred range
The CV value can be increased by up to about 8% compared to a normal dilute phosphoric acid aqueous electrolyte, and tan δ and leakage current do not deteriorate.
次に本発明の方法を実施例にもとづいてより具
体的に説明する。 Next, the method of the present invention will be explained in more detail based on examples.
市販の燐酸は約85％のH3PO4濃度を残部の水か
ら成つており、これに五酸化燐を添加して水分と
反応させることによつてより高濃度の燐酸溶液を
調製することができる。試料面積８cm2のタンタル
箔を硫酸−硝酸−弗酸系混酸で化学研磨し、清浄
な表面状態にしたのち、先にのべたような調製法
によつて作成した種々の濃度の電解液を用いて、
25℃で2mA／cm2の電流密度で対極に対して50Vま
で定電流化成したのちこの電圧で２時間定電圧化
成した。こののち銀板を対極とした23％の硫酸水
溶液中で、静電容量と損失を120Hzでキヤパシタ
ンスブリツジを用いて測定し、さらに対極に対し
て30Vの正電圧を３分間印加したのちの漏れ電流
を測定した。図は、陽極酸化用電解液中のH3PO4
濃度と上記の陽極酸化試料の電気特性の関係を示
したものである。 Commercially available phosphoric acid consists of approximately 85% H 3 PO 4 concentration and the balance is water, and a higher concentration phosphoric acid solution can be prepared by adding phosphorus pentoxide to this and reacting with water. can. A tantalum foil with a sample area of 8 cm 2 was chemically polished with a mixed acid of sulfuric acid, nitric acid, and hydrofluoric acid to obtain a clean surface, and then electrolytes of various concentrations prepared by the preparation method described above were used. hand,
Constant current formation was performed at 25°C with a current density of 2 mA/cm 2 to 50 V with respect to the counter electrode, and then constant voltage formation was performed at this voltage for 2 hours. After this, capacitance and loss were measured using a capacitance bridge at 120 Hz in a 23% sulfuric acid aqueous solution with a silver plate as the counter electrode, and a positive voltage of 30 V was applied to the counter electrode for 3 minutes. The leakage current was measured. The figure shows H 3 PO 4 in the electrolyte for anodizing.
This figure shows the relationship between the concentration and the electrical properties of the above-mentioned anodic oxidation sample.
図から明らかなように、本発明の陽極酸化法に
よれば、漏れ電流および損失tanδは従来の希薄
燐酸水溶液電解液の場合と同水準であつて、より
大きなCV値の陽極酸化膜を得ることができる。
したがつてタンタルコンデンサの小形化、タンタ
ル金属の節減を可能にするものである。 As is clear from the figure, according to the anodic oxidation method of the present invention, the leakage current and loss tan δ are at the same level as in the case of the conventional dilute phosphoric acid aqueous electrolyte, and an anodic oxide film with a larger CV value can be obtained. Can be done.
Therefore, it is possible to downsize the tantalum capacitor and save tantalum metal.
図は、タンタル陽極酸化皮膜の電気特性と陽極
酸化に用いる電解液のH3PO4濃度の関係を示した
ものである。
The figure shows the relationship between the electrical properties of the tantalum anodic oxide film and the H 3 PO 4 concentration of the electrolyte used for anodization.
Claims (1)
なる電解液を用いることを特徴とするタンタル金
属の陽極酸化法。1. A method for anodizing tantalum metal, characterized by using an electrolytic solution consisting of 90 to 99% by weight of H 3 PO 4 and the balance water.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14514280A JPS5770293A (en) | 1980-10-16 | 1980-10-16 | Anodic oxidation of tantalum metal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14514280A JPS5770293A (en) | 1980-10-16 | 1980-10-16 | Anodic oxidation of tantalum metal |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5770293A JPS5770293A (en) | 1982-04-30 |
| JPS6253594B2 true JPS6253594B2 (en) | 1987-11-11 |
Family
ID=15378382
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14514280A Granted JPS5770293A (en) | 1980-10-16 | 1980-10-16 | Anodic oxidation of tantalum metal |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5770293A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0240887A (en) * | 1988-07-29 | 1990-02-09 | Matsushita Electric Ind Co Ltd | Microwave oven |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2015132297A1 (en) * | 2014-03-04 | 2015-09-11 | Friedrich-Alexander-Universität Erlangen-Nürnberg | Electrolyte for anodization and anodized surface |
| CN109285703A (en) * | 2018-10-26 | 2019-01-29 | 中国振华(集团)新云电子元器件有限责任公司(国营第四三二六厂) | The method for improving the method for tantalum capacitor voltage endurance capability and making tantalum capacitor |
-
1980
- 1980-10-16 JP JP14514280A patent/JPS5770293A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0240887A (en) * | 1988-07-29 | 1990-02-09 | Matsushita Electric Ind Co Ltd | Microwave oven |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5770293A (en) | 1982-04-30 |
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