US 12,375,061 B2
Transversely-excited film bulk acoustic resonator matrix filters
Pintu Adhikari, West Lafayette, IN (US); Neal Fenzi, Santa Barbara, CA (US); and Andrew Guyette, San Mateo, CA (US)
Assigned to Murata Manufacturing Co., Ltd., Nagaokakyo (JP)
Filed by Murata Manufacturing Co., Ltd., Nagaokakyo (JP)
Filed on Sep. 29, 2023, as Appl. No. 18/478,193.
Application 18/478,193 is a continuation of application No. 17/830,219, filed on Jun. 1, 2022, granted, now 11,811,377.
Application 17/830,219 is a continuation of application No. 17/133,849, filed on Dec. 24, 2020, granted, now 11,405,019, issued on Aug. 2, 2022.
Application 17/133,849 is a continuation in part of application No. 17/121,724, filed on Dec. 14, 2020, granted, now 11,405,017, issued on Aug. 2, 2022.
Claims priority of provisional application 63/087,789, filed on Oct. 5, 2020.
Prior Publication US 2024/0030895 A1, Jan. 25, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. H03H 9/56 (2006.01); H03H 3/02 (2006.01); H03H 9/02 (2006.01); H03H 9/17 (2006.01); H03H 9/54 (2006.01)
CPC H03H 9/564 (2013.01) [H03H 3/02 (2013.01); H03H 9/02228 (2013.01); H03H 9/174 (2013.01); H03H 9/542 (2013.01); H03H 2003/023 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A radio frequency filter, comprising:
a substrate;
at least one piezoelectric layer above the substrate, portions of the at least one piezoelectric layer over respective cavities of the radio frequency filter;
a conductor pattern at the at least one piezoelectric layer, the conductor pattern including a plurality of interdigital transducers (IDTs) of a respective plurality of resonators, interleaved fingers of each IDT disposed on respective portions of the at least one piezoelectric layer over the respective cavities, wherein the conductor pattern connects the plurality of resonators in a matrix filter circuit comprising a first sub-filter and a second sub-filter, each sub-filter comprising two or more resonators from the plurality of resonators;
a first dielectric layer having a first thickness and that is over the IDTs of the two or more resonators of the first sub-filter; and
a second dielectric layer having a second thickness and that is over the IDTs of the two or more resonators of the second sub-filter, the first thickness being different than the second thickness,
wherein either the first or second dielectric layer has a thickness tdn, and
wherein the radiofrequency filter further comprises a passivation layer of dielectric having a thickness tpass at each of the plurality of resonators, wherein tdn≥tpass.