Acoustic wave device and manufacturing method for acoustic wave device

An acoustic wave device comprising:

• a first substrate having piezoelectricity, and including a first main surface and a second main surface;
• a second substrate including a third main surface and a fourth main surface facing the third main surface;
• a functional electrode provided on the first main surface to perform electromechanical conversion with the first substrate;
• a plurality of first plane electrodes provided on the first main surface and connected to the functional electrode;
• a plurality of second plane electrodes provided on the third main surface;
• a third plane electrode provided on the first main surface to be in contact with an end side of the first substrate, and not connected to the functional electrode and the first plane electrode;
• and
• a plurality of bump electrodes bonded to the first main surface and the third main surface;
• wherein
• a maximum distance between two end portions of the third plane electrode is smaller than a minimum distance of distances between two of the plurality of bump electrodes having different potentials.

A manufacturing method for an acoustic wave device, the method comprising:

• manufacturing a collective board by forming a functional electrode to perform electromechanical conversion with a piezoelectric wafer having piezoelectricity and including a first main surface and a second main surface, a plurality of first plane electrodes connected to the functional electrode, a stylus electrode provided on a dicing line with a predetermined cutting width, and a plurality of bump electrodes, on the first main surface of the piezoelectric wafer;
• inspecting a bandpass characteristic of an IDT electrode including the functional electrode and the plurality of first plane electrodes by bringing a measuring stylus into contact with the stylus electrode;
• dividing the collective board into a plurality of individualized acoustic wave chips by cutting the collective board along the dicing line with a dicing machine after inspecting the bandpass characteristic of the IDT electrode;
• and
• bonding the plurality of bump electrodes of each of the plurality of individualized acoustic wave chips to a third main surface on which a plurality of second plane electrodes of a mounting substrate are formed;
• wherein
• in manufacturing the collective board, the stylus electrode includes slit portions connected to the functional electrode, and no conductive material is formed in both end portions in a direction perpendicular to the dicing line;
• and
• a portion of the slit portion overlaps the dicing line when the collective board is viewed in a plan view.