Ceramic green sheet, method for manufacturing multilayer ceramic capacitor, and multilayer ceramic capacitor

Patent metadata

Field	Value
Publication number	US-9799450-B2
Application number	US-201615072580-A
Country	US
Kind code	B2
Filing date	Mar 17, 2016
Priority date	Sep 20, 2013
Publication date	Oct 24, 2017
Grant date	Oct 24, 2017

Abstract

A ceramic green sheet where the proportion of a Si-containing constituent coating the surface of barium titanate-based ceramic particles is 95% or higher, and the proportion of a rare-earth element-containing constituent coating the surface of the barium titanate-based ceramic particle is 85% or higher.

First claim

The invention claimed is:

1. A ceramic green sheet comprising:
a barium titanate-based ceramic particle as a main inorganic component;
a Si-containing constituent having, when measured after removal of a binder, a coverage of 95% or greater along a surface of the barium titanate-based ceramic particle;
Dy 2 O 3 having, when measured after removal of the binder, a coverage of 85% or greater along the surface of the barium titanate-based ceramic particle;
a Ba constituent;
a Mg constituent;
a Mn constituent; and
a Si constituent,
wherein, when a total content of Ti is 100 parts by mol:
a content of Dy is 4.0 parts by mol;
a content of Mg is 0.25 parts by mol;
a content of Mn is 0.25 parts by mol; and
a content of Si is 1.5 parts by mol.

2. The ceramic green sheet according to claim 1 , wherein the ceramic green sheet has a Ba/Ti molar ratio of 1.01.

3. A method for manufacturing a multilayer ceramic capacitor, the method comprising:
forming ceramic green sheets containing:
a barium titanate-based ceramic particle as a main inorganic component,
a Si-containing constituent having, when measured after removal of a binder, a coverage of 95% or greater along a surface of the barium titanate-based ceramic particle, and
Dy 2 O 3 having, when measured after removal of the binder, a coverage of 85% or greater along the surface of the barium titanate-based ceramic particle;
a Ba constituent,
a Mg constituent,
a Mn constituent, and
a Si constituent;

forming electrode-pattern sheets by applying a conductive paste to some of the ceramic green sheets in a predetermined pattern;
forming an unfired stacked structure by stacking the electrode pattern sheets with the ceramic green sheets interposed therebetween;
firing the unfired stacked structure to form a multilayer ceramic element having a plurality of dielectric layers and a plurality of internal electrodes opposed to each other with the dielectric layers interposed therebetween; and
forming an external electrode electrically connected to the internal electrodes on the multilayer ceramic element,
wherein, when a total content of Ti in the ceramic green sheets is 100 parts by mol:
a content of Dy is 4.0 parts by mol;
a content of Mg is 0.25 parts by mol;
a content of Mn is 0.25 parts by mol; and
a content of Si is 1.5 parts by mol.

4. The method for manufacturing a multilayer ceramic capacitor according to claim 3 , wherein the plurality of dielectric layers have a Ba/Ti molar ratio of 1.01.

5. A multilayer ceramic capacitor comprising:
a multilayer ceramic element comprising a plurality of dielectric layers comprising a barium titanate-based ceramic, Dy, Ba, Mg, Mn and Si, and a plurality of internal electrodes opposed to each other with the dielectric layers interposed therebetween; and
an external electrode on a surface of the multilayer ceramic element and electrically connected to the internal electrodes,
wherein the Dy is present at 98% or greater of all grain boundaries in the barium titanate-based ceramic of the dielectric layers, and
wherein, when a total content of Ti is 100 parts by mol in the plurality of dielectric layers:
a content of Dy is 4.0 parts by mol;
a content of Mg is 0.25 parts by mol;
a content of Mn is 0.25 parts by mol; and
a content of Si is 1.5 parts by mol.

6. The multilayer ceramic capacitor according to claim 5 , wherein the plurality of dielectric layers have a Ba/Ti molar ratio of 1.01.

Assignees

• Murata Manufacturing Co

Inventors

• Oguni Toshimi

Classifications

• C04B2235/3418

  Silicon oxide, silicic acids or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint · CPC title

• C04B2235/3224

  Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide · CPC title

• C04B37/001

  directly with other burned ceramic articles · CPC title

• H01G4/30

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

• C04B35/62815

  Rare earth metal oxides · CPC title