Acoustic wave device

An acoustic wave device comprising:

• a support with a thickness extending in a first direction;
• a piezoelectric layer extending in the first direction of the support;
• and
• an interdigital transducer electrode extending in the first direction of the piezoelectric layer and including a plurality of first electrode fingers extending in a second direction orthogonal to the first direction, a first busbar electrode connected to the plurality of first electrode fingers, a plurality of second electrode fingers extending in the second direction and facing corresponding ones of the plurality of first electrode fingers in a third direction orthogonal to the second direction, and a second busbar electrode connected to the plurality of second electrode fingers;
• wherein
• the support includes a hollow on a side thereof adjacent to the piezoelectric layer and the hollow at least partially overlaps the interdigital transducer electrode in plan view in the first direction;
• the piezoelectric layer includes at least one first through hole penetrating the piezoelectric layer in a region between at least one first electrode finger and the second busbar electrode in plan view in the first direction;
• and
• the first through hole communicates with the hollow and overlaps in plan view in the first direction an end portion of the at least one first electrode finger that is not connected to the first busbar electrode.