Ceramic electronic component with low equivalent series resistance and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-9805871-B2
Application number	US-201615352670-A
Country	US
Kind code	B2
Filing date	Nov 16, 2016
Priority date	Jul 10, 2013
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

External electrodes, electrically connected to exposed portions of internal electrodes, are arranged on end surfaces of a ceramic main body of a laminated ceramic capacitor. Alloy layers of a metal contained in internal electrodes, and a metal contained in external electrodes, are arranged at the boundaries between external electrodes, and the ceramic main body and internal electrodes. Plating layers are provided on surfaces of external electrodes. A ceramic electronic component having a reduced ESR is thus provided.

First claim

What is claimed is:

1. A ceramic electronic component comprising:
a ceramic main body including a plurality of laminated ceramic layers;
internal electrodes disposed inside the ceramic main body, the internal electrodes including respective exposed portions exposed on an end surface of the ceramic main body;
an external electrode arranged on the end surface of the ceramic main body so as to be electrically connected with each of the exposed portions of the internal electrodes; and
a plating film arranged on the external electrode; wherein
the external electrode includes a metal medium in which metal powder is integrated and a glass medium in which glass powder is integrated;
an alloy layer of a metal contained in the external electrode and a metal contained in each of the internal electrodes is located at an interface between the external electrode, and the ceramic main body and the internal electrodes so as to extend across adjacent exposed portions of the internal electrodes; and
the metal medium and the glass medium are located between the alloy layer and the plating film.

2. The ceramic electronic component according to claim 1 , wherein the metal medium is made of Cu.

3. The ceramic electronic component according to claim 1 , wherein the alloy layer is a Ni—Cu alloy layer.

4. The ceramic electronic component according to claim 1 , wherein a coverage ratio of the alloy layer on the end surface of the ceramic main body is about 72% or more.

5. The ceramic electronic component according to claim 1 , wherein a distance between exposed portions of a plurality of the internal electrodes adjacent to each other on the end surface of the ceramic main body is about 4 mm or less.

6. The ceramic electronic component according to claim 1 , wherein an exposed ratio of the internal electrodes on the end surface of the ceramic main body is about 60% to about 80%.

7. The ceramic electronic component according to claim 1 , wherein the metal powder of the metal medium of the external electrode has an aspect ratio of approximately 8 to 15.

8. The ceramic electronic component according to claim 1 , wherein the metal medium is present nearer to a surface of the external electrode than the alloy layer located between the external electrode, and the ceramic main body and the internal electrodes.

9. The ceramic electronic component according to claim 1 , wherein a proportion of the metal medium in the external electrode is about 70% to about 75% by volume.

10. The ceramic electronic component according to claim 1 , wherein a proportion of the glass medium in the external electrode is about 25% to about 30% by volume.

11. The ceramic electronic component according to claim 1 , wherein the plating film includes at least two plating films including a Ni plating film and a Sn plating film.

12. The ceramic electronic component according to claim 1 , wherein the ceramic electronic component is one of a capacitor, a piezoelectric component, a thermistor, and an inductor.

13. The ceramic electronic component according to claim 1 , wherein the external electrode is arranged on a side surface of the ceramic main body.

14. A method for manufacturing the ceramic electronic component according to claim 1 , comprising the steps of:
preparing the ceramic main body in which the internal electrodes are disposed;
applying, to the end surface of the ceramic main body on which the exposed portions of the internal electrodes are exposed, a conductive paste containing metal powder having a particle size of about 0.5 μm to about 2 μm and glass powder having a particle size larger than the particle size of the metal powder; and
heat-treating the conductive paste to form the external electrode on the end surface of the ceramic main body on which the exposed portions of the internal electrodes are exposed, and to form the alloy layer at the interface between the external electrode, and the ceramic main body and the internal electrodes.

15. The method according to claim 14 , wherein
the glass powder has a softening point higher than a temperature at which the metal contained in the internal electrodes diffuses into the metal contained in the external electrode; and
a heat-treatment temperature for the conductive paste is higher than the softening point of the glass powder.

16. The method according to claim 14 , wherein the metal medium is made of Cu.

17. The method according to claim 14 , wherein the alloy layer is a Ni—Cu alloy layer.

18. The method according to claim 14 , wherein a coverage ratio of the alloy layer on the end surface of the ceramic main body is about 72% or more.

19. The method according to claim 14 , wherein a distance between exposed portions of a plurality of the internal electrodes adjacent to each other on the end surface of the ceramic main body is about 4 mm or less.

20. The method according to claim 14 , wherein an exposed ratio of the internal electrodes on the end surface of the ceramic main body is about 60% to about 80%.

Assignees

• Murata Manufacturing Co

Inventors

• Onishi Kosuke
• Sasaki Tomohiro
• Nishisaka Yasuhiro
• Ishizuka Akira
• Yoshida Akihiro

Classifications

• H01G4/248

  the terminals embracing or surrounding the capacitive element, e.g. caps (H01G4/252 takes precedence) · CPC title

• H01F27/29 Primary

  Terminals; Tapping arrangements {for signal inductances} · CPC title

• H01F2027/2809

  on stacked layers · CPC title

• H01C7/008

  Thermistors (H01C7/02 - H01C7/06 take precedence) · CPC title

• H01G4/005 Primary

  Electrodes · CPC title