Electrode geometry to minimize stress in transversely-excited film bulk acoustic resonators

An acoustic resonator device comprising:

• a substrate;
• a piezoelectric plate disposed on the substrate and that includes a diaphragm that extends across a cavity over the substrate;
• a first conductor level disposed on a surface of the piezoelectric plate and including:
• first and second interdigital transducer (IDT) first-level busbars extending along opposing sides of the diaphragm, and
• first and second sets of IDT fingers extending from the first and second first-level busbars, respectively, with the first and second sets of IDT fingers being interleaved and disposed on the diaphragm;
• and
• a second conductor level that extends at least partially over the first conductor level and that includes first and second second-level busbars that overlap at least portions of the first and second first-level busbars, respectively, in a thickness direction of the acoustic resonator device,
• wherein a portion of at least one of the first and second second-level busbars has a rounded corner disposed above the diaphragm in the thickness direction of the acoustic resonator device.