Acoustic wave device

An acoustic wave device comprising:

• an acoustic wave element;
• a plurality of bumps electrically connected to the acoustic wave element;
• an under-bump metal layer between the acoustic wave element and the plurality of bumps;
• a wiring substrate on which the acoustic wave element is mounted;
• and
• an encapsulating body covering the acoustic wave element on the wiring substrate;
• wherein
• the acoustic wave element includes a support substrate, a piezoelectric layer on one main surface of the support substrate, and a functional electrode on at least one main surface of the piezoelectric layer;
• the wiring substrate is electrically connected to the acoustic wave element via the under-bump metal layer and the plurality of bumps;
• the piezoelectric layer includes a hole passing through the piezoelectric layer on at least a portion of a straight line connecting the functional electrode and the bumps to each other;
• the support substrate includes a dielectric layer on the one main surface thereof;
• and
• the hole extends to the dielectric layer.

An acoustic wave device comprising:

• an acoustic wave element;
• a plurality of bumps electrically connected to the acoustic wave element;
• an under-bump metal layer between the acoustic wave element and the plurality of bumps;
• a wiring substrate on which the acoustic wave element is mounted;
• and
• an encapsulating body covering the acoustic wave element on the wiring substrate;
• wherein
• the acoustic wave element includes a support substrate, a piezoelectric layer on one main surface of the support substrate, and a functional electrode on at least one main surface of the piezoelectric layer;
• the wiring substrate is electrically connected to the acoustic wave element via the under-bump metal layer and the plurality of bumps;
• the piezoelectric layer includes a hole passing through the piezoelectric layer on at least a portion of a straight line connecting the functional electrode and the bumps to each other;
• the support substrate includes a hollow portion in the one main surface thereof;
• the piezoelectric layer is provided on the one main surface of the support substrate to cover the hollow portion;
• the functional electrode is provided such that a portion thereof overlaps the hollow portion in a direction in which the support substrate and the piezoelectric layer are laminated together;
• and
• the hole communicates with the hollow portion.