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US-20260128231-A1 - MULTILAYER CERAMIC CAPACITOR

US20260128231A1US 20260128231 A1US20260128231 A1US 20260128231A1US-20260128231-A1

Abstract

A multilayer ceramic capacitor includes a ceramic body including six surfaces including main surfaces, side surfaces, and end surfaces, and external electrodes on the ceramic body and connected to some of internal electrode layers. The external electrodes include glass domains. In a longitudinal direction, a ratio of a sum of lengths, in a longitudinal direction, of the glass domains to a sum of lengths of a surface of an electrode arrangement portion on at least one of the side surfaces and the main surfaces, and of a surface of a corner portion contiguous with the surface of the electrode arrangement portion is about 40% to about 60%, and a ratio of a number of glass domains extending from a surface of the ceramic body to a surface of the external electrode located in the electrode arrangement portion is about 10% to about 30%.

Inventors

  • Sadayuki KOIZUMI
  • Tetsuya KISUMI

Assignees

  • MURATA MANUFACTURING CO., LTD.

Dates

Publication Date
20260507
Application Date
20260106
Priority Date
20230718

Claims (12)

  1. 1 . A multilayer ceramic capacitor comprising: a ceramic base body including a plurality of dielectric layers and a plurality of internal electrode layers that are laminated, and six surfaces including a first main surface and a second main surface opposed to each other in a height direction, a first lateral surface and a second lateral surface opposed to each other in a width direction orthogonal or substantially orthogonal to the height direction, and a first end surface and a second end surface opposed to each other in a length direction orthogonal or substantially orthogonal to the height direction and the width direction; and external electrodes on the ceramic base body and each connected to some of the plurality of internal electrode layers; wherein when a portion, among the six surfaces of the ceramic base body, where any of the external electrodes is provided is defined as an electrode placement portion, and, when a portion, in the ceramic base body, where two of the six surfaces intersect is defined as a corner portion, the external electrodes include glass domains; a ratio of a sum of lengths in the length direction of the glass domains relative to a sum of lengths in the length direction of a surface of the ceramic base body in the electrode placement portion on at least one surface among the first lateral surface, the second lateral surface, the first main surface, and the second main surface and a surface of the ceramic base body in the corner portion continuous to the at least one surface in the length direction is about 40% or more and about 60% or less; and among the glass domains provided in the electrode placement portion, a ratio of a number of glass domains extending from the at least one surface of the ceramic base body to a corresponding one of surfaces of the external electrodes is about 10% or more and about 30% or less.
  2. 2 . The multilayer ceramic capacitor according to claim 1 , wherein, in one of the external electrodes provided on at least one of the first lateral surface, the second lateral surface, the first main surface, and the second main surface, the glass domains occupy about two-thirds or more of a length in a film thickness direction of the one of the external electrodes.
  3. 3 . The multilayer ceramic capacitor according to claim 1 , wherein each of the external electrodes includes a metal domain.
  4. 4 . The multilayer ceramic capacitor according to claim 3 , wherein the metal domain includes at least one of copper, nickel, silver, palladium, silver-palladium alloy, or gold.
  5. 5 . The multilayer ceramic capacitor according to claim 1 , wherein the glass domains include at least one of boron, silicon, barium, magnesium, aluminum, or lithium.
  6. 6 . The multilayer ceramic capacitor according to claim 1 , wherein the ratio of the number of glass domains extending from the at least one surface of the ceramic base body to a corresponding one of surfaces of the external electrodes is about 20%.
  7. 7 . The multilayer ceramic capacitor according to claim 1 , wherein the glass domains include copper powder having a D50 average particle size of about 1 μm and a spherical particle shape, and copper powder having a D50 average particle size of about 4 μm and a flat particle shape.
  8. 8 . The multilayer ceramic capacitor according to claim 1 , wherein the glass domains include glass particles having a D50 average particle size of about 0.5 μm or more and about 2.2 μm or less.
  9. 9 . The multilayer ceramic capacitor according to claim 1 , wherein the glass domains include glass particles having a D50 average particle size of about 0.5 μm or more and about 1.0 μm or less.
  10. 10 . The multilayer ceramic capacitor according to claim 1 , further comprising a nickel plating film on each of the external electrodes and a tin plating layer on the nickel plating layer.
  11. 11 . The multilayer ceramic capacitor according to claim 1 , wherein a thickness of each of the external electrode layers is about 3 μm or more and about 25 μm or less.
  12. 12 . The multilayer ceramic capacitor according to claim 1 , wherein a thickness of each of the plurality of dielectric layers is about 0.3 μm or more and about 10 μm or less.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to Japanese Patent Application No. 2023-116993 filed on Jul. 18, 2023 and is a Continuation Application of PCT Application No. PCT/JP2024/017925 filed on May 15, 2024. The entire contents of each application are hereby incorporated herein by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to multilayer ceramic capacitors. 2. Description of the Related Art In the process of forming external electrodes of multilayer ceramic capacitors, blisters may be formed in the external electrodes. Blisters are cavities formed inside the external electrodes. When blisters are formed in the external electrodes, problems such as reduced electrical conductivity of the external electrodes or reduced reliability of the external electrodes may occur. Regarding methods for reducing blisters, Japanese Unexamined Patent Application, Publication No. H04-95307 describes adjusting the material composition of external electrodes. However, in the conventional technology, the reduction or prevention of blister occurrence is not sufficient. SUMMARY OF THE INVENTION Example embodiments of the present invention provide multilayer ceramic capacitors that are each able to more reliably reduce or prevent blisters. An example embodiment of the present invention provides a multilayer ceramic capacitor which includes a ceramic base body including a plurality of dielectric layers and a plurality of internal electrode layers that are laminated, and six surfaces including a first main surface and a second main surface opposed to each other in a height direction, a first lateral surface and a second lateral surface opposed to each other in a width direction orthogonal or substantially orthogonal to the height direction, and a first end surface and a second end surface opposed to each other in a length direction orthogonal or substantially orthogonal to the height direction and the width direction, and external electrodes on the ceramic base body and each connected to some of the plurality of internal electrode layers. When a portion, among the six surfaces of the ceramic base body, where any of the external electrodes is provided is defined as an electrode placement portion, and when a portion, in the ceramic base body, where two of the six surfaces intersect is defined as a corner portion, the external electrodes include glass domains, a ratio of a sum of lengths in the length direction of the glass domains relative to a sum of lengths in the length direction of a surface of the ceramic base body in the electrode placement portion on at least one surface among the first lateral surface, the second lateral surface, the first main surface, and the second main surface and a surface of the ceramic base body in the corner portion continuous to the at least one surface in the length direction is about 40% or more and about 60% or less, and among the glass domains provided in the electrode placement portion, a ratio of a number of glass domains extending from the at least one surface of the ceramic base body to a corresponding one of surfaces of the external electrodes is about 10% or more and about 30% or less. According to example embodiments of the present invention, multilayer ceramic capacitors that are each able to more reliably reduce or prevent blisters are provided. The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the example embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a multilayer ceramic capacitor according to an example embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line I-I in FIG. 1. FIG. 3 is a cross-sectional view taken along the line II-II in FIG. 1. FIG. 4 is an enlarged view of a portion enclosed by a frame in FIG. 2. FIG. 5 is an LT cross-sectional view showing the arrangement of glass domains. FIG. 6 is an LT cross-sectional view showing the electrically conductive paste after application and drying. FIG. 7 is an LT cross-sectional view showing the electrically conductive paste after firing. FIG. 8 is a three-dimensional focused ion beam scanning electron microscope image of an external electrode. DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS Example embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a perspective view of a multilayer ceramic capacitor 1 according to an example embodiment of the present invention. FIG. 1 shows a two-terminal multilayer ceramic capacitor. The multilayer ceramic capacitors according to example embodiments of the present invention are not limited to two-terminal multilayer ceramic capacitors. The multilayer ceramic capacitors according to example embodiments of the present inv