Multi-layer ceramic capacitor and method of producing the same

Patent metadata

Field	Value
Publication number	US-2020258689-A1
Application number	US-202016777578-A
Country	US
Kind code	A1
Filing date	Jan 30, 2020
Priority date	Feb 13, 2019
Publication date	Aug 13, 2020
Grant date	—

Abstract

A multi-layer ceramic capacitor includes: a first region including a polycrystal including, as a main component, crystal grains free from intragranular pores; a second region that includes a polycrystal including, as a main component, crystal grains including intragranular pores and includes a higher content of silicon than a content of silicon in the first region; a capacitance forming unit including ceramic layers laminated along a first direction, and internal electrodes disposed between the ceramic layers; and a protective portion including a cover that covers the capacitance forming unit and constitutes a main surface facing in the first direction, a side margin constituting a side surface facing in a second direction orthogonal to the first direction, and a ridge constituting a connection portion, the connection portion connecting the main surface and the side surface to each other. The ceramic layers include the first region. The ridge includes the second region.

First claim

What is claimed is:

1 . A multi-layer ceramic capacitor, comprising:
a first region including a polycrystal including, as a main component, crystal grains free from intragranular pores; a second region that includes a polycrystal including, as a main component, crystal grains including intragranular pores and includes a higher content of silicon than a content of silicon in the first region; a capacitance forming unit including
ceramic layers laminated along a first direction, and
internal electrodes disposed between the ceramic layers; and
a protective portion including
a cover that covers the capacitance forming unit and constitutes a main surface facing in the first direction,
a side margin constituting a side surface facing in a second direction orthogonal to the first direction, and
a ridge constituting a connection portion, the connection portion connecting the main surface and the side surface to each other, wherein
the ceramic layers include the first region, and the ridge includes the second region.

2 . The multi-layer ceramic capacitor according to claim 1 , wherein
the content of silicon of the second region is 0.5 mol % or more.

3 . The multi-layer ceramic capacitor according to claim 1 , wherein
the side margin includes the second region.

4 . The multi-layer ceramic capacitor according to claim 3 , wherein
a dimension of the side margin in the second direction is 30 μm or less.

5 . The multi-layer ceramic capacitor according to claim 3 , wherein
the protective portion includes the second region over the entire protective portion.

6 . The multi-layer ceramic capacitor according to claim 1 , wherein
the cover includes the second region.

7 . The multi-layer ceramic capacitor according to claim 1 , wherein
each of the first region and the second region includes a polycrystal having a Perovskite structure including barium and titanium.

8 . A method of producing a multi-layer ceramic capacitor, comprising:
preparing a first powder including, as a main component, ceramic particles free from intragranular pores; preparing a second powder including, as a main component, ceramic particles having a Perovskite structure having an axis ratio c/a of 1.008 or less and including intragranular pores; producing an unsintered multi-layer unit that includes
a capacitance forming unit including
ceramic layers laminated along a first direction and including the first powder as a main component, and
internal electrodes disposed between the ceramic layers, and

a cover that covers the capacitance forming unit in the first direction;
producing an unsintered ceramic body by forming a side margin on a side surface of the multi-layer unit, the side surface facing in a second direction orthogonal to the first direction, the side margin including the second powder as a main component and a higher content of silicon than a content of silicon in the ceramic layers; and sintering the ceramic body.

9 . The method of producing a multi-layer ceramic capacitor according to claim 8 , wherein
the side margin is formed by attaching a ceramic sheet to the side surface.

10 . A method of producing a multi-layer ceramic capacitor, comprising:
preparing a first powder including, as a main component, ceramic particles free from intragranular pores; preparing a second powder including, as a main component, ceramic particles having a Perovskite structure having an axis ratio c/a of 1.008 or less and including intragranular pores; producing an unsintered ceramic body including
a multi-layer unit including
ceramic layers laminated along a first direction and including the first powder as a main component,
internal electrodes disposed between the ceramic layers, and
a side margin that covers the internal electrodes in a second direction orthogonal to the first direction, and

a cover that covers the multi-layer unit in the first direction and includes the second powder as a main component and a higher content of silicon than a content of silicon in the ceramic layers; and
sintering the ceramic body.

11 . The method of producing a multi-layer ceramic capacitor according to claim 8 , wherein
the second powder is produced by a hydrothermal method.

12 . The method of producing a multi-layer ceramic capacitor according to claim 8 , wherein
the second powder has a mean particle size of 5 nm or more and 500 nm or less.

13 . The method of producing a multi-layer ceramic capacitor according to claim 8 , wherein
the first powder is produced by a solid-phase method.

Assignees

• Taiyo Yuden Kk

Inventors

• Kato Yoichi

Classifications

• H01G4/224

  Housing; Encapsulation · CPC title

• H01G4/1281

  with grain boundary layer · CPC title

• B32B18/00

  Layered products essentially comprising ceramics, e.g. refractory products · CPC title

• H01G4/232

  electrically connecting two or more layers of a stacked or rolled capacitor · CPC title

• C04B2235/768

  Perovskite structure ABO3 · CPC title