Acoustic wave device and communication module
An acoustic wave device includes a first substrate having first and second surfaces opposite from each other, and side surfaces connecting the first and second surfaces, a first acoustic wave element disposed on the first surface of the first substrate, a second substrate that is provided over the first surface of the first substrate and over the first acoustic wave element and has a first air gap between the second and first substrates, a second acoustic wave element disposed on the second substrate, a ground terminal disposed on the second surface of the first substrate, a first metal layer provided between the first and second acoustic wave elements and located in the first air gap, and a second metal layer that covers half or more of a total area of the side surfaces of the first substrate and electrically connects the first metal layer and the ground terminal.
1. An acoustic wave device comprising:
a first substrate having a first surface, a second surface opposite from the first surface, and side surfaces connecting the first surface and the second surface;
a first acoustic wave element disposed on the first surface of the first substrate;
a second substrate that is provided over the first surface of the first substrate and over the first acoustic wave element and has a first air gap between the second substrate and the first substrate;
a second acoustic wave element disposed on the second substrate;
a ground terminal disposed on the second surface of the first substrate;
a first metal layer provided between the first acoustic wave element and the second acoustic wave element and located in the first air gap; and
a second metal layer that covers half or more of a total area of the side surfaces of the first substrate and electrically connects the first metal layer and the ground terminal; and
a terminal that is electrically connected to the second acoustic wave element, insulated from the second metal layer, and provided on the second surface of the first substrate.
2. The acoustic wave device according to claim 1 , wherein the second metal layer covers the side surfaces from first ends, which are at a side of the first surface, of the side surfaces of the first substrate to second ends, which are at a side of the second surface, of the side surfaces of the first substrate.
3. The acoustic wave device according to claim 1 , wherein the second metal layer is provided on each of the side surfaces of the first substrate, and covers at least a part of each of the side surfaces.
4. The acoustic wave device according to claim 1 , wherein the second metal layer covers 90% or more of the total area of the side surfaces of the first substrate.
5. The acoustic wave device according to claim 1 , further comprising:
a ring-shaped metal layer that is provided on the first surface of the first substrate, surrounds the first acoustic wave element, seals the first acoustic wave element in the first air gap between the first substrate and the second substrate, and is electrically connected to the first metal layer,
wherein the second metal layer is in contact with at least a part of a surface of the ring-shaped metal layer from the side surfaces of the first substrate.
6. The acoustic wave device according to claim 5 ,
wherein the second substrate includes a third surface opposite to the first substrate, a fourth surface opposite from the third surface, and side surfaces connecting the third surface and the fourth surface,
wherein the second acoustic wave element is disposed on the third surface, and is sealed in the first air gap together with the first acoustic wave element by the ring-shaped metal layer,
wherein the second metal layer covers surfaces extending from the side surfaces of the first substrate to the side surfaces of the second substrate and the fourth surface through the surface of the ring-shaped metal layer.
7. The acoustic wave device according to claim 5 , further comprising:
a sealing portion provided over a third surface opposite from a fourth surface of the second substrate, the fourth surface being opposite to the first surface of the first substrate,
wherein the second acoustic wave element is disposed on the third surface, and is sealed in a second air gap between the second substrate and the sealing portion by the sealing portion, the second air gap being different from the first air gap,
wherein the second metal layer covers surfaces extending from the side surfaces of the first substrate to side surfaces, which connect the third surface and the fourth surface, of the second substrate and a surface of the sealing portion through the surface of the ring-shaped metal layer.
8. The acoustic wave device according to claim 1 , further comprising: a via wiring penetrating through the first substrate from the first surface to the second surface, and electrically connecting a wiring electrically connected to the first acoustic wave element and the ground terminal.
9. The acoustic wave device according to claim 1 ,
wherein the first acoustic wave element is provided in plural on the first substrate, and the first acoustic wave elements form a first acoustic wave filter,
wherein the second acoustic wave element is provided in plural on the second substrate, and the second acoustic wave elements form a second acoustic wave filter having a passband different from a passband of the first acoustic wave filter, and
wherein the first acoustic wave filter and the second acoustic wave filter form a multiplexer.
10. A communication module comprising:
a circuit substrate; and
the acoustic wave device according to claim 1 mounted on the circuit substrate.
11. The acoustic wave device according to claim 1 ,
wherein the second acoustic wave element is electrically connected to the terminal through a wiring electrically connected to the second acoustic wave element, a pillar provided between the first substrate and the second substrate and penetrating through the first metal layer, and a via wiring provided in the first substrate.
12. The acoustic wave device according to claim 1 ,
wherein the second metal layer is provided on two opposing side surfaces of the side surfaces of the first substrate.