Multilayer ceramic capacitor and method for producing the same

Patent metadata

Field	Value
Publication number	US-2016358713-A1
Application number	US-201615163950-A
Country	US
Kind code	A1
Filing date	May 25, 2016
Priority date	Jun 5, 2015
Publication date	Dec 8, 2016
Grant date	—

Abstract

A multilayer ceramic capacitor having inner electrodes containing at least one metal selected from Cu, Ag, Pd, Pt, Rh, Ir, Ru, and Os in an amount of 0.1 atom % or more that is dissolved in Ni and Sn to form a solid solution. The percentage of Sn with respect to the total amount of Ni and Sn in near-surface regions each located at a depth of 2 nm from a surface of the inner electrode in contact with an adjacent ceramic dielectric layer is 1.4 or more atom %, and X−Y≧1.0, where X represents the atomic percentage of Sn in the near-surface regions and Y represents the atomic percentage of Sn in mid-thickness regions of the inner electrodes. A method for producing a multilayer ceramic capacitor includes annealing the ceramic multilayer body to increase, in the inner electrodes, the percentage of Sn in the near-surface regions.

First claim

What is claimed is:

1 . A multilayer ceramic capacitor comprising:
a ceramic multilayer body including a stack of a plurality of ceramic dielectric layers and a plurality of inner electrodes arranged opposing each other with a respective ceramic dielectric layer of the plurality of ceramic dielectric layers interposed therebetween; and outer electrodes disposed on an outer surface of the ceramic multilayer body, each outer electrode being in electrical connection with a respective set of inner electrodes of the plurality of inner electrodes, the inner electrodes including a Ni—Sn-Metal A alloy, wherein the Metal A is at least one metal selected from the group consisting of Cu, Ag, Pd, Pt, Rh, Ir, Ru, and Os in an amount of 0.1 atom % or more, a percentage of Sn with respect to a total amount of Ni and Sn in near-surface regions of the plurality of inner electrodes is 1.4 or more atom %, each of the near-surface regions being a region at a depth of within 2 nm from a surface in contact with an adjacent one of the respective ceramic dielectric layers, and
X−Y≧ 1.0
where X represents an atomic percentage of Sn in the near-surface regions and Y represents an atomic percentage of Sn in mid-thickness regions of the plurality of inner electrodes.

2 . The multilayer ceramic capacitor according to claim 1 , wherein the plurality of inner electrodes have a thickness defined as T, and each of the mid-thickness regions is located 0.2 T or more inward from each surface of the plurality of inner electrodes in a thickness direction thereof.

3 . The multilayer ceramic capacitor according to claim 1 , wherein the Ni—Sn-Metal A alloy contains a solid solution of Ni, Sn and the Metal A.

4 . The multilayer ceramic capacitor according to claim 1 , wherein the plurality of inner electrodes contain a co-material.

5 . The multilayer ceramic capacitor according to claim 4 , wherein the co-material contains at least some constituent elements of a ceramic material of the ceramic dielectric layers.

6 . A method for producing a multilayer ceramic capacitor, the method comprising:
forming an unsintered ceramic multilayer body that includes (i) a stack of a plurality of unsintered ceramic dielectric layers and (ii) a plurality of unsintered inner electrode patterns disposed between adjacent unsintered ceramic dielectric layers of the plurality of unsintered ceramic dielectric layers, the unsintered inner electrode patterns comprising a conductive paste containing a Ni component, a Sn component, and at least one metal component selected from the group consisting of Cu, Ag, Pd, Pt, Rh, Ir, Ru, and Os; sintering the unsintered ceramic multilayer body to obtain a ceramic multilayer body containing ceramic dielectric layers and inner electrodes; and annealing the ceramic multilayer body to increase, in the inner electrodes, a percentage of Sn with respect to a total amount of Ni and Sn in near-surface regions of the inner electrodes is 1.4 or more atom %, each of the near-surface regions being a region at a depth of within 2 nm from a surface in contact with an adjacent ceramic dielectric layers, such that X−Y≧1.0, where X represents an atomic percentage of Sn in the near-surface regions and Y represents an atomic percentage of Sn in mid-thickness regions of the inner electrodes.

7 . The method for producing a multilayer ceramic capacitor according to claim 6 , wherein the sintering is conducted by heating the unsintered ceramic multilayer body at a rate of 20° C./min to a temperature of 1200° C., holding the temperature for 20 minutes.

8 . The method for producing a multilayer ceramic capacitor according to claim 7 , wherein the sintering is conducted in a reducing atmosphere containing a H 2 —N 2 —H 2 O gas with an oxygen partial pressure of about 10 −10 to 10 −12 MPa.

9 . The method for producing a multilayer ceramic capacitor according to claim 6 , wherein the annealing is conducted in an atmosphere with an oxygen partial pressure of 10 −12 to 10 −15 MPa at 800 to 1000° C. for 1 to 4 hours.

10 . The method for producing a multilayer ceramic capacitor according to claim 6 , wherein the inner electrodes have a thickness defined as T, and each of the mid-thickness regions is located 0.2 T or more inward from each surface of the inner electrodes in a thickness direction thereof.

11 . The method for producing a multilayer ceramic capacitor according to claim 6 , wherein the conductive paste contains a solid solution of Ni, Sn and the Metal A.

12 . The method for producing a multilayer ceramic capacitor according to claim 6 , wherein the conductive paste contains a co-material.

13 . The method for producing a multilayer ceramic capacitor according to claim 12 , wherein the co-material contains at least some constituent elements of a ceramic material of the ceramic dielectric layers.

Assignees

• Murata Manufacturing Co

Inventors

• Doi Akitaka
• Yamaguchi Shinichi
• Suzuki Shoichiro

Classifications

• H01G4/0085

  Fried electrodes · CPC title

• H01G4/30 Primary

  Stacked capacitors (H01G4/33 takes precedence) · CPC title

• H01G4/306 Primary

  made by thin film techniques · CPC title

• H01G4/012

  Form of non-self-supporting electrodes · CPC title

• H01G4/1209

  characterised by the ceramic dielectric material (H01G4/1272, H01G4/1281 take precedence) · CPC title