Filter device

A filter device comprising:

• a first chip comprising:
• a substrate including a base and an intermediate layer;
• a piezoelectric layer attached to the substrate;
• and
• a conductor pattern on a surface of the piezoelectric layer, the conductor pattern including interleaved fingers of a plurality of interdigital transducers (IDTs) of a plurality of resonators;
• a first dielectric layer of the first chip having a first thickness disposed on and between the interleaved fingers of a first resonator of the plurality of resonators of the first chip;
• a second dielectric layer of the first chip having a second thickness greater than the first thickness of the first chip disposed on and between the interleaved fingers of a second resonator of the plurality of resonators of the first chip,
• wherein each IDT comprises a first busbar, a second busbar, and the interleaved fingers extending alternately from the first and second busbars, wherein overlapping portions of the interleaved fingers are disposed on the piezoelectric layer;
• and
• a second chip comprising:
• a substrate including a base and an intermediate layer;
• a piezoelectric layer attached to the substrate;
• and
• a conductor pattern on a surface of the piezoelectric layer, the conductor pattern including interleaved fingers of a plurality of interdigital transducers (IDTs) of a plurality of resonators;
• a first dielectric layer of the second chip having a first thickness disposed on and between the interleaved fingers of a first resonator of the plurality of resonators of the second chip;
• a second dielectric layer of the second chip having a second thickness greater than the first thickness of the second chip disposed on and between the interleaved fingers of a second resonator of the plurality of resonators of the second chip,
• wherein each IDT comprises a first busbar, a second busbar, and the interleaved fingers extending alternately from the first and second busbars, wherein overlapping portions of the interleaved fingers are disposed on the piezoelectric layer.