US 12,255,608 B2
Transversely-excited film bulk acoustic resonator with buried oxide strip acoustic confinement structures
Andrew Kay, Provo, UT (US); Sean McHugh, Santa Barbara, CA (US); John Koulakis, Los Angeles, CA (US); and Albert Cardona, Santa Barbara, CA (US)
Assigned to Murata Manufacturing Co., Ltd., Nagaokakyo (JP)
Filed by Murata Manufacturing Co., Ltd., Nagaokakyo (JP)
Filed on Mar. 29, 2022, as Appl. No. 17/707,732.
Application 17/707,732 is a continuation of application No. 17/555,353, filed on Dec. 17, 2021.
Application 17/555,353 is a continuation in part of application No. 17/542,290, filed on Dec. 3, 2021.
Claims priority of provisional application 63/237,050, filed on Aug. 25, 2021.
Claims priority of provisional application 63/208,503, filed on Jun. 9, 2021.
Claims priority of provisional application 63/191,897, filed on May 21, 2021.
Claims priority of provisional application 63/187,932, filed on May 12, 2021.
Claims priority of provisional application 63/182,465, filed on Apr. 30, 2021.
Prior Publication US 2022/0352869 A1, Nov. 3, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. H03H 9/02 (2006.01); H03H 3/02 (2006.01); H03H 9/13 (2006.01); H03H 9/17 (2006.01); H03H 9/56 (2006.01)
CPC H03H 9/02228 (2013.01) [H03H 3/02 (2013.01); H03H 9/02031 (2013.01); H03H 9/132 (2013.01); H03H 9/174 (2013.01); H03H 9/176 (2013.01); H03H 9/562 (2013.01); H03H 9/564 (2013.01); H03H 2003/023 (2013.01)] 22 Claims
OG exemplary drawing
 
1. A filter comprising:
a substrate;
a piezoelectric layer supported by the substrate;
a plurality of diaphragms, each diaphragm comprising a respective portion of the piezoelectric layer that is over a respective cavity of the filter; and
a conductor pattern on the piezoelectric layer, the conductor pattern comprising interdigital transducers (IDTs) of a plurality of acoustic resonators, each IDT comprising interleaved interdigital transducer (IDT) fingers extending from first and second busbars respectively, wherein:
the interleaved IDT fingers of each of the plurality of acoustic resonators are on a respective diaphragm, and
overlapping portions of the interleaved IDT fingers of each of the plurality of acoustic resonators define an aperture of the respective acoustic resonator,
wherein each of the plurality of acoustic resonators further comprises:
a first dielectric strip that overlaps the interleaved IDT fingers in a first margin of the aperture and extends into a first gap between the first margin and the first busbar; and
a second dielectric strip that overlaps the interleaved IDT fingers in a second margin of the aperture and extends into a second gap between the second margin and the second busbar, and
wherein a thickness ts of each of the first and second dielectric strips of a first acoustic resonator of the plurality of acoustic resonators is different than a thickness ts of each of the first and second dielectric strips of a second acoustic resonator of the plurality of acoustic resonators.