Electrolytic capacitor, circuit board containing electrolytic capacitor, and method for producing the same

• US 6,504,705 B2
• Filed: 10/11/2001
• Issued: 01/07/2003
• Est. Priority Date: 10/12/2000
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Nakatani, Seiichi, Shimada, Mikinari, Shiraishi, Seigo, Nakada, Yasuhiko, Handa, Hiroyuki, Ishikawa, Akihiro
• Primary Examiner(s): Dinkins, Anthony
• Application Number:
  US09/976,438
• Publication Number:
  US 20020075633A1
• Time in Patent Office: 453 Days
• Field of Search: 361/523, 361/528, 361/529, 361/530, 361/508, 361/509, 361/531, 361/532, 29/250.3
• US Class Current: 361/528
• CPC Class Codes: H01G 11/48 Conductive polymers
• CPC Class Codes: H01G 11/56 Solid electrolytes, e.g. gels; Additives therein
• CPC Class Codes: H01G 9/15 Solid electrolytic capacitors H01G11/00 takes precedence
• CPC Class Codes: H01L 2224/16227 the bump connector connecting to a bond pad of the item
• CPC Class Codes: H05K 1/141 One or more single auxiliary printed circuits mounted on a main printed circuit, e.g. modules, adapters H05K1/142 and H05K1/147 take precedence
• CPC Class Codes: H05K 1/162 incorporating printed capacitors
• CPC Class Codes: H05K 1/185 Components encapsulated in the insulating substrate of the printed circuit or incorporated in internal layers of a multilayer circuit semiconductor chips encapsulated by interconnect and support structures H01L23/5389, H01L24/00
• CPC Class Codes: H05K 2201/0187 with regions of different dielectrics in the same layer, e.g. in a printed capacitor for locally changing the dielectric properties
• CPC Class Codes: H05K 2201/0323 Carbon
• CPC Class Codes: H05K 2201/0329 Intrinsically conductive polymer [ICP]; Semiconductive polymer
• CPC Class Codes: H05K 2203/0315 Oxidising metal
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors

Abstract

In an electrolytic capacitor of the present invention, a dielectric layer is provided on a surface of a valve metal element for an anode having a capacitor forming part and an electrode lead part, and further, a solid electrolyte layer and a charge collecting layer for a cathode are provided in this order thereon. The capacitor forming part and the electrode lead part of the valve metal element for an anode have rough surface layers on their surfaces, and are compressed in the thickness direction of the rough surface layers. Further, a region other than the electrode lead part and the charge collecting element for cathode is molded with a molding material. Exposed portions of the electrode lead part and the charge collecting element for cathode function as electrode terminals, respectively.

Claims

1. An electrolytic capacitor, comprising:

a valve metal element for an anode including a capacitor forming part and an electrode lead part;

a dielectric layer provided on a surface of the valve metal element for anode;

a solid electrolyte layer provided on the dielectric layer; and

a charge collecting element for a cathode provided on the solid electrolyte layer,

wherein, in the valve metal element for an anode, the capacitor forming part and the electrode lead part have a rough surface layer on surfaces thereof, and are compressed in a thickness direction of the rough surface layer.

2. The electrolytic capacitor according to claim 1, further comprising:

a conductive via hole bored entirely through in a thickness direction, the conductive via hole being provided in a region other than the capacitor forming part, and being insulated electrically from the valve metal element for an anode, the solid electrolyte layer, and the charge collecting element for a cathode.

3. The electrolytic capacitor according to claim 1, wherein a thickness index of the rough surface layer in the capacitor forming part after compression is not less than 0.5 and less than 1.0,

where the thickness index of the rough surface layer after compression is a thickness of the rough surface layer after compression in the case where a thickness of the rough surface layer before compression is assumed to be 1.

4. The electrolytic capacitor according to claim 1, wherein a thickness index of the rough surface layer in the electrode lead part after compression is not more than 0.5,

where the thickness index of the rough surface layer after compression is a thickness of the rough surface layer after compression in the case where a thickness of the rough surface layer before compression is assumed to be 1.

5. The electrolytic capacitor according to claim 1, wherein conductive particles are embedded in the electrode lead part so that the conductive particles are exposed on a surface of the electrode lead part.

6. The electrolytic capacitor according to claim 5, wherein the conductive particles are selected from the group consisting of Au particles, Ag particles, Cu particles, Ni particles, and C particles.

7. The electrolytic capacitor according to claim 1, wherein the charge collecting element for a cathode is made of a metal foil in which carbon particles are embedded so that the particles are exposed on a surface of the metal foil.

8. The electrolytic capacitor according to claim 1, wherein the charge collecting element for cathode is a cladding material, the cladding material including:

a metal foil in which carbon particles are embedded so that the particles are exposed on a surface of the metal foil; and

a cladding layer.

9. The electrolytic capacitor according to claim 1, wherein the capacitor forming part and the electrode lead part are provided on a same plane of the valve metal element for anode.

10. The electrolytic capacitor according to claim 1, wherein:

the capacitor forming part is provided on a first side of the valve metal element for an anode; and

the electrode lead part is provided on a second side of the valve metal element for an anode, the second side being opposite to the first side.

11. The electrolytic capacitor according to claims 1, wherein:

the valve metal element for an anode includes a valve metal layer and a metal layer.

12. The electrolytic capacitor according to claim 11, wherein the metal layer is made of Cu or Ni.

13. The electrolytic capacitor according to claim 1, wherein a region other than a predetermined portion of the electrode lead part and a predetermined portion of the charge collecting element for cathode is sealed with a molding material.

14. The electrolytic capacitor according to claim 13, wherein at least one of the electrode lead part and the charge collecting element for a cathode has a plurality of portions not covered with the molding material.

15. A method for producing the electrolytic capacitor according to claim 1, the method comprising:

roughening at least a surface of a portion of the valve metal element for an anode, the portion being that to be the capacitor forming part; and

compressing the roughened surface portion of the valve metal element for anode in the thickness direction.

16. The method according to claim 15, wherein the compressing step is carried out so that a thickness index of the rough surface layer in the capacitor forming part after compression is not less than 0.5 and less than 1.0,

where the thickness index of the rough surface layer after compression is a thickness of the rough surface layer after compression in the case where a thickness of the rough surface layer before compression is assumed to be 1.

17. The method according to claim 15, wherein the compressing step is carried out so that a thickness index of the rough surface layer in the electrode lead part after compression is not more than 0.5,

where the thickness index of the rough surface layer after compression is a thickness of the rough surface layer after compression in the case where a thickness of the rough surface layer before compression is assumed to be 1.

18. The method according to claim 15, further comprising the step of:

placing conductive particles on the electrode lead part in a state in which the dielectric layer is formed on a surface of the electrode lead part, and compressing the electrode lead part so that the conductive particles are embedded in the electrode lead part.

19. The method according to claim 15, further comprising the steps of:

forming the dielectric layer;

forming the solid electrolyte layer; and

repairing the dielectric layer,

wherein the roughening step, the dielectric layer forming step, the solid electrolyte layer forming step, the compressing step, and the dielectric layer repairing step are carried out in the stated order.

20. A circuit board comprising the electrolytic capacitor according to claim 1.

21. The circuit board according to claim 20, wherein:

the electrolytic capacitor is embedded in an insulation material having a wire layer; and

the electrode lead part of the valve metal element for an anode and the charge collecting element for a cathode are connected individually with the wire layer.

22. The circuit board according to claim 21, wherein the insulation material is a composite material containing inorganic material particles and a thermosetting resin.

23. A method for producing the electrolytic-capacitor-containing circuit board according to claim 20, the method comprising:

burying the electrolytic capacitor in the insulation material in a non-cured state by pressing,

wherein a pressure in the burying step is smaller than a pressure applied to the capacitor forming part of the valve metal element for an anode of the electrolytic capacitor when it is compressed.