Electronic device mounting board, electronic package, and electronic module

1. An electronic device mounting board, comprising:

a substrate on which an electronic device is mountable, the substrate including a first layer and a second layer located on a lower surface of the first layer;

a plurality of first through-cavities located through the first layer in a thickness direction of the first layer; and

at least one second through-cavity located through the second layer in a thickness direction of the second layer, the at least one second through-cavity overlapping the plurality of first through-cavities in a plan view,

wherein each of the plurality of first through-cavities is continuous with the at least one second through-cavity, and

wherein in at least one place where the first through-cavity and the second through-cavity overlap each other, the first through-cavity has an end portion located outward from a periphery of an outermost one of a plurality of the second through-cavity, and the second through-cavity has an end portion located outward from a periphery of an outermost one of the plurality of first through-cavities in a plan view, such that a first end portion of the first through-cavity and a second end portion of the first through cavity are located outward from the periphery of the outermost one of a plurality of the second through-cavity.

2. The electronic device mounting board according to claim 1 , wherein

the plurality of first through-cavities are located parallel to one another.

3. The electronic device mounting board according to claim 1 , wherein

the plurality of first through-cavities and the at least one second through-cavity are quadrangular in a plan view, and

the plurality of first through-cavities each have a longer side that is longer than a longer side of the at least one second through-cavity.

4. The electronic device mounting board according to claim 1 , wherein

an outermost portion of the plurality of first through-cavities in a plan view is located outward from an end portion of the at least one second through-cavity in a plan view.

5. The electronic device mounting board according to claim 1 , wherein

at least one of the plurality of first through-cavities include a curved end portion in a plan view.

6. The electronic device mounting board according to claim 1 , wherein

the at least one second through-cavity includes a curved end portion in a plan view.

7. The electronic device mounting board according to claim 1 , wherein

at least one of the plurality of first through-cavities includes an end portion overlapping an end portion of the substrate.

8. The electronic device mounting board according to claim 1 , further comprising:

a third layer located on a lower surface of the second layer.

9. The electronic device mounting board according to claim 8 , further comprising:

a bottom plate with higher thermal conductivity than the substrate located on a lower surface of the third layer.

10. The electronic device mounting board according to claim 1 , further comprising:

a bottom plate with higher thermal conductivity than the substrate located on a lower surface of the second layer.

11. The electronic device mounting board according to claim 1 , wherein

the plurality of first through-cavities comprise at least three first through-cavities, and

the at least one second through-cavity connects end portions of all the first through-cavities.

12. The electronic device mounting board according to claim 1 , wherein

the at least one second through-cavity overlaps end portions of adjacent ones of the plurality of first through-cavities.

13. The electronic device mounting board according to claim 1 , wherein

the plurality of first through-cavities and the at least one second through-cavity are sequentially continuous with one another into a single space.

14. An electronic package, comprising:

the electronic device mounting board according to claim 1 ; and

an electronic device mounted on the electronic device mounting board.

15. An electronic module, comprising:

the electronic package according to claim 14 ; and

a housing located above the electronic package.

16. The electronic device mounting board according to claim 1 , wherein a channel through which a heat-dissipating substance flows in or flows out is located on a lower surface or a side surface of a substrate.

17. An electronic device mounting board, comprising:

a substrate on which an electronic device is mountable, the substrate including a first layer and a second layer located on a lower surface of the first layer;

a plurality of first through-cavities located through the first layer in a thickness direction of the first layer; and

at least one second through-cavity located through the second layer in a thickness direction of the second layer, the at least one second through-cavity overlapping the plurality of first through-cavities in a plan view,

wherein each of the plurality of first through-cavities is continuous with the at least one second through-cavity,

wherein in at least one place where the first through-cavity and the second through-cavity overlap each other, the first through-cavity has an end portion located outward from a periphery of an outermost one of a plurality of the second through-cavity, and the second through-cavity has an end portion located outward from a periphery of an outermost one of the plurality of first through-cavities in a plan view, and

wherein at least one of an end portion of a first through-cavity and an end portion of a second through-cavity has a circular shape having a diameter that is greater than a width in a direction perpendicular to a longitudinal direction of a corresponding through-cavity.

18. An electronic device mounting board, comprising:

a substrate on which an electronic device is mountable, the substrate including a first layer and a second layer located on a lower surface of the first layer;

a plurality of first through-cavities located through the first layer in a thickness direction of the first layer; and

at least one second through-cavity located through the second layer in a thickness direction of the second layer, the at least one second through-cavity overlapping the plurality of first through-cavities in a plan view,

wherein each of the plurality of first through-cavities is continuous with the at least one second through-cavity,

wherein in at least one place where the first through-cavity and the second through-cavity overlap each other, the first through-cavity has an end portion located outward from a periphery of an outermost one of a plurality of the second through-cavity, and the second through-cavity has an end portion located outward from a periphery of an outermost one of the plurality of first through-cavities in a plan view, and

wherein the plurality of first through-cavities and the plurality of second through-cavities are connected together into a single space.