Patent ID: 11967946
Assignee: MURATA MANUFACTURING CO., LTD.
Field: Basic communication processes (Electrical engineering)
Classification: CPC H | IPC H

Claim 11:
12. A method of fabricating an acoustic resonator device comprising:
forming a bonding layer on a surface of a device substrate;
forming an etch-stop layer sandwiched between the bonding layer and a first surface of a piezoelectric layer having a second surface attached to a sacrificial substrate;
removing the sacrificial substrate to expose the second surface of the piezoelectric layer;
using an etch process to form a cavity, wherein a portion of the piezoelectric layer and the etch-stop layer, but not the bonding layer, form a diaphragm spanning the cavity; and
forming an interdigital transducer (IDT) at the piezoelectric layer such that interleaved fingers of the IDT are disposed on the diaphragm,
wherein the etch-stop layer is impervious to the etch process used to form the cavity.