Transversely-excited film bulk acoustic resonator with multiple diaphragm thicknesses and fabrication method
US12212306B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 3, 2021 |
| Grant date | Jan 28, 2025 |
| Priority date | — |
| Expiry date | Mar 7, 2043 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H2003/023
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Methods of fabricating filter devices are disclosed. A back surface of a piezoelectric plate having a first thickness is attached to a substrate. The front surface of the piezoelectric plate is selectively etched to thin a portion of the piezoelectric plate from the first thickness to a second thickness less than the first thickness. Cavities are formed in the substrate such that portions of the piezoelectric plate form a plurality of diaphragms spanning respective cavities. A conductor pattern is formed on the front surface. The conductor pattern includes a first interdigital transducer (IDT) with interleaved fingers on a first diaphragm having the first thickness and a second IDT with interleaved fingers on a second diaphragm having the second thickness.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.