Transversely-excited film bulk acoustic resonator using pre-formed cavities
AssigneeMurata Manufacturing Co., Ltd.
InventorPatrick Turner
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Abstract
Acoustic resonator devices, filter devices, and methods of making acoustic resonator devices and filter devices. An acoustic resonator device includes a substrate with a cavity and an alignment pattern in a surface of the substrate. The cavity and the alignment pattern have a same depth. A back surface of a piezoelectric plate is attached to the surface of the substrate. A portion of the piezoelectric plate that spans the cavity forms a diaphragm. An interdigital transducer (IDT) is on a front surface of the piezoelectric plate. Interleaved fingers of the IDT are on the diaphragm.
Claims20
An acoustic resonator device comprising:
- a substrate comprising a cavity and an alignment pattern in a surface of the substrate, wherein the cavity and the alignment pattern have a same depth;
- a piezoelectric plate having front and back surfaces, the back surface attached to the surface of the substrate, wherein a portion of the piezoelectric plate that spans the cavity forms a diaphragm;
- and
- an interdigital transducer (IDT) on the front surface of the piezoelectric plate, wherein interleaved fingers of the IDT are on the diaphragm.
The device of claim 6, wherein the substrate further comprises an SiO2 coating.
A filter device comprising:
- a substrate comprising a plurality of cavities and an alignment pattern in a surface of the substrate, wherein the plurality of cavities and the alignment pattern have a same depth;
- a plate having front and back surfaces, the back surface attached to the surface of the substrate, wherein portions of the piezoelectric plate that span each of the plurality of cavities form respective diaphragms;
- and
- a conductor pattern formed on the front surface, the conductor pattern comprising a plurality of interdigital transducers (IDTs) of a respective plurality of acoustic resonators, wherein interleaved fingers of each of the plurality of IDTs are on respective diaphragms.
A method of forming an acoustic resonator device, the method comprising:
- forming a cavity and an alignment pattern in a substrate, wherein the cavity and the alignment pattern have a same depth;
- attaching a back surface of a piezoelectric plate having front and back surfaces to the surface of the substrate, wherein a portion of the piezoelectric plate that spans the cavity forms a diaphragm;
- and
- forming an interdigital transducer (IDT) formed on the front surface of the piezoelectric plate, wherein interleaved fingers of the IDT are on the diaphragm.
Dependencies are inferred from the claim text.