Multi-layer ceramic electronic component, method of producing a multi-layer ceramic electronic component, and circuit board

1. A multi-layer ceramic electronic component, comprising:

a ceramic body including

a first end surface and a second end surface facing in a direction of a first axis,

a multi-laver unit including internal electrodes and ceramic layers alternately laminated in a direction of a second axis orthogonal to the first axis and drawn from the first end surface or the second end surface, and

a pair of covers disposed outside the multi-layer unit in the direction of the second axis;

a first external electrode disposed to cover the first end surface; and

a second external electrode disposed to cover the second end surface, wherein

each of the first external electrode and the second external electrode has an electrode end surface facing in the direction of the first axis,

each electrode end surface includes

a pair of first peripheral regions located at peripheral edges in the direction of the second axis, and

a first concave region located between the pair of first peripheral regions and recessed from the pair of first peripheral regions, and

in a cross-section obtained by bisecting the multi-layer ceramic electronic component in a direction of a third axis orthogonal to the first axis and the second axis, b/a is 0.004 or more and 0.025 or less, where a is a height dimension of the first concave region in the direction of the second axis, and b is a depth dimension of the first concave region in the direction of the first axis,

wherein each of the first end surface and the second end surface of the ceramic body includes

a pair of second peripheral regions located at peripheral edges in the direction of the second axis, and

a second concave region located between the pair of second peripheral regions and recessed from the pair of second peripheral regions inwardly in the direction of the first axis,

the pair of first peripheral regions cover the pair of second peripheral regions,

the first concave region covers the second concave region, and

the pair of second peripheral regions are disposed on flat surfaces of the pair of covers orthogonal to the first axis.

2. The multi-layer ceramic electronic component according to claim 1 , wherein

the ceramic body is configured such that a dimension in the direction of the second axis is larger than a dimension in the direction of the third axis.

3. The multi-layer ceramic electronic component according to claim 1 , wherein

the multi-layer ceramic electronic component has a dimension in the direction of the first axis and in the direction of the third axis of 0.2 mm or more and 2.0 mm or less.

4. The multi-layer ceramic electronic component according to claim 1 , wherein

the multi-layer ceramic electronic component has a dimension in the direction of the second axis of 300 μm or less.

5. The multi-layer ceramic electronic component according to claim 1 , wherein

the pair of second peripheral regions have a width in the direction of the second axis of 4 μm or more and 70 μm or less.

6. The multi-layer ceramic electronic component according to claim 5 , wherein

the pair of second peripheral regions have a width in the direction of the second axis of 6 μm or more and 55 μm or less.

7. The multi-layer ceramic electronic component according to claim 6 , wherein

the pair of second peripheral regions have a width in the direction of the second axis of 11 μm or more and 35 μm or less.

8. A method of producing a multi-layer ceramic electronic component, comprising:

producing a ceramic body including

a first end surface and a second end surface facing in a direction of a first axis,

a multi-layer unit including internal electrodes and ceramic layers alternately laminated in a direction of a second axis orthogonal to the first axis and drawn from the first end surface or the second end surface; and

a pair of covers disposed outside the multi-layer unit in the direction of the second axis; and

forming a first external electrode disposed to cover the first end surface, and a second external electrode disposed to cover the second end surface, wherein

each of the first external electrode and the second external electrode has an electrode end surface facing in the direction of the first axis,

the electrode end surface includes

a pair of first peripheral regions located at peripheral edges in the direction of the second axis, and

a first concave region located between the pair of first peripheral regions and recessed from the pair of first peripheral regions, and

in a cross-section obtained by bisecting the multi-layer ceramic electronic component in a direction of a third axis orthogonal to the first axis and the second axis, b/a is 0.004 or more and 0.025 or less, where a is a length of an imaginary line segment connecting boundaries between each of the pair of first peripheral regions and the first concave region, and b is a length of a longest perpendicular line in the direction of the first axis among perpendicular lines extending from the line segment to the first concave region,

wherein each of the first end surface and the second end surface of the ceramic body includes

a pair of second peripheral regions located at peripheral edges in the direction of the second axis, and

a second concave region located between the pair of second peripheral regions and recessed from the pair of second peripheral regions inwardly in the direction of the first axis,

the pair of first peripheral regions cover the pair of second peripheral regions,

the first concave region covers the second concave region, and

the pair of second peripheral regions are disposed on flat surfaces of the pair of covers orthogonal to the first axis.

9. The method of producing a multi-layer ceramic electronic component according to claim 8 , wherein

the producing the ceramic body includes

preparing first ceramic sheets having a first density and second ceramic sheets having a second density larger than the first density, the first ceramic sheets and the second ceramic sheets including unsintered internal electrodes,

laminating the second ceramic sheets outside a laminate in the direction of the second axis, the laminate including the first ceramic sheets laminated in the direction of the second axis, and

sintering a laminate including the first ceramic sheets and the second ceramic sheets, and

an expression of 0.050≤(d−c)/d≤0.150 is satisfied, where c is the first density and d is the second density.

10. A circuit board, comprising:

a mounting board;

a multi-layer ceramic electronic component including

a ceramic body including

a first end surface and a second end surface facing in a direction of a first axis,

a first main surface and a second main surface facing in a direction of a second axis orthogonal to the first axis,

a multi-layer multi-laver unit including internal electrodes and ceramic layers alternately laminated in the direction of the second axis and drawn from the first end surface or the second end surface, and

a pair of covers disposed outside the multi-layer unit in the direction of the second axis,

a first external electrode disposed to cover the first end surface, and

a second external electrode disposed to cover the second end surface,

the multi-layer ceramic electronic component being disposed such that the first main surface or the second main surface faces the mounting board;

a first solder that connects the first external electrode and the mounting board to each other; and

a second solder that connects the second external electrode and the mounting board to each other, wherein

each of the first external electrode and the second external electrode has an electrode end surface facing in the direction of the first axis,

each electrode end surface includes

a pair of first peripheral regions located at peripheral edges in the direction of the second axis, and

a first concave region located between the pair of first peripheral regions and recessed from the pair of first peripheral regions, and

in a cross-section obtained by bisecting the multi-layer ceramic electronic component in a direction of a third axis orthogonal to the first axis and the second axis, b/a is 0.004 or more and 0.025 or less, where a is a height dimension of the first concave region in the direction of the second axis, and b is a depth dimension of the first concave region in the direction of the first axis,

wherein each of the first end surface and the second end surface of the ceramic body includes

a pair of second peripheral regions located at peripheral edges in the direction of the second axis, and

a second concave region located between the pair of second peripheral regions and recessed from the pair of second peripheral regions inwardly in the direction of the first axis,

the pair of first peripheral regions cover the pair of second peripheral regions,

the first concave region covers the second concave region, and

the pair of second peripheral regions are disposed on flat surfaces of the pair of covers orthogonal to the first axis.