Solid electrolytic capacitor for a tantalum embedded microchip

Patent metadata

Field	Value
Publication number	US-11257629-B2
Application number	US-201916268610-A
Country	US
Kind code	B2
Filing date	Feb 6, 2019
Priority date	Feb 12, 2018
Publication date	Feb 22, 2022
Grant date	Feb 22, 2022

Abstract

A solid electrolytic capacitor and method for making the capacitor are provided. The capacitor includes a porous anode body, an anode foil, a dielectric, a cathode, and anode and cathode terminations. The foil is disposed on a planar surface of the anode body, and both comprise a valve metal. Further, the dielectric overlies at least a portion of the anode body, and the dielectric is also formed within the anode body. The cathode overlies at least a portion of the dielectric that overlies the anode body and includes a solid electrolyte, where at least a portion of a lower surface of the foil is free of both the dielectric and the solid electrolyte. In addition, the anode termination is electrically connected to the portion of the lower surface of the foil that is free of both the dielectric and the solid electrolyte, and the cathode termination is electrically connected to the solid electrolyte.

First claim

What is claimed is:

1. A solid electrolytic capacitor, comprising:
a porous anode body;
an anode foil, wherein the anode foil is impermeable to liquids, is disposed only on a lower planar surface of the porous anode body, and extends up to but not beyond a side surface of the porous anode body, wherein an upper surface of the anode foil is in direct contact with the lower planar surface of the porous anode body, wherein the anode foil has a width less than or equal to a width of the porous anode body, wherein the anode foil has a thickness ranging from 10 micrometers to 75 micrometers, further wherein the porous anode body and the anode foil comprise a valve metal;
a dielectric overlying at least a portion of the porous anode body, wherein the dielectric is also formed within the porous anode body;
a cathode overlying at least a portion of the dielectric that overlies the porous anode body, the cathode comprising a solid electrolyte, wherein transmission of the solid electrolyte from the upper surface of the anode foil to a lower surface of the anode foil is prevented, and wherein at least a portion of the lower surface of the anode foil is free of the dielectric and the solid electrolyte;
an anode termination that is electrically connected to the portion of the lower surface of the anode foil that is free of the dielectric and the solid electrolyte; and
a cathode termination that is electrically connected to the solid electrolyte, wherein the solid electrolytic capacitor is free of an anode lead wire.

2. The solid electrolytic capacitor of claim 1 , wherein the valve metal comprises tantalum, niobium, aluminum, hafnium, titanium, an electrically conductive oxide thereof, or an electrically conductive nitride thereof.

3. The solid electrolytic capacitor of claim 1 , wherein the upper surface of the anode foil is welded to the planar surface of the porous anode body.

4. The solid electrolytic capacitor of claim 1 , wherein an oxidation resistant metal layer is disposed between the anode foil and the anode termination.

5. The solid electrolytic capacitor of claim 1 , wherein the solid electrolyte comprises manganese dioxide, a conductive polymer, or a combination thereof.

6. The solid electrolytic capacitor of claim 1 , wherein a carbon layer overlies the cathode.

7. The solid electrolytic capacitor of claim 6 , wherein a metal layer overlies the carbon layer.

8. The solid electrolytic capacitor of claim 7 , wherein the metal layer comprises silver.

9. The solid electrolytic capacitor of claim 1 , wherein the solid electrolytic capacitor has a thickness of from about 250 micrometers to about 1000 micrometers, and wherein the anode termination and the cathode termination each have a thickness ranging from about 10 micrometers to about 100 micrometers.

10. The solid electrolytic capacitor of claim 1 , wherein the anode termination and the cathode termination each comprise a conductive paste.

11. The solid electrolytic capacitor of claim 1 , wherein the solid electrolytic capacitor includes a coating of an insulating resin, wherein at least a portion of the anode termination and a portion of the cathode termination are exposed and free of the coating.

12. A module comprising a plurality of the solid electrolytic capacitors of claim 1 , wherein the plurality of solid electrolytic capacitors are arranged in series, in parallel, or in a non-polar configuration.

13. A method for forming a solid electrolytic capacitor, the method comprising:
forming a porous anode body from a powder;
sintering the porous anode body;
welding an upper surface of an anode foil to only a lower planar surface of the sintered porous anode body such that the anode foil extends up to but not beyond a side surface of the porous anode body, wherein an upper surface of the anode foil is in direct contact with the lower planar surface of the sintered porous anode body, wherein the anode foil is impermeable to liquids and has a width less than or equal to a width of the porous anode body, wherein the anode foil has a thickness ranging from 10 micrometers to 75 micrometers, further wherein the powder and the anode foil are formed from a valve metal;
anodically oxidizing at least a portion of the sintered porous anode body to form a dielectric that overlies at least a portion of the sintered porous anode body, wherein the dielectric is also formed within the sintered porous anode body;
applying a solid electrolyte to at least a portion of the anodically oxidized sintered porous anode body, wherein transmission of the solid electrolyte from the upper surface of the anode foil to a lower surface of the anode foil is prevented, and wherein at least a portion of the lower surface of the anode foil is free of the dielectric and the solid electrolyte;
electrically connecting the portion of the lower surface of the anode foil that is free of the dielectric and the solid electrolyte to an anode termination; and
electrically connecting the solid electrolyte to a cathode termination, wherein the solid electrolytic capacitor is free of an anode lead wire.

14. The method of claim 13 , wherein the sintered porous anode body and the anode foil are sintered in a reducing environment.

15. The method of claim 13 , wherein an oxidation resistant metal layer is applied to the anode foil before the anode foil is electrically connected to the anode termination.

16. The method of claim 13 , wherein the solid electrolytic capacitor has a thickness ranging from about 250 micrometers to about 1000 micrometers.

17. The method of claim 13 , wherein a carbon layer is applied over the solid electrolyte and a metal layer is applied over the carbon layer.

18. The method of claim 13 , further comprising coating the solid electrolytic capacitor with an insulating resin, wherein at least a portion of the anode termination and a portion of the cathode termination are exposed and free of the coating.

Assignees

• Avx Corp
• Kyocera Avx Components Corp

Inventors

• Paulus Joseph W
• Sturmer John
• Laforge Jason

Classifications

• H01G9/26

  Structural combinations of electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices with each other · CPC title

• H01G9/052

  Sintered electrodes · CPC title

• H01G9/028

  Organic semiconducting electrolytes, e.g. TCNQ · CPC title

• H01G9/0036

  Formation of the solid electrolyte layer · CPC title

• H01G9/07

  Dielectric layers · CPC title