US 12,113,510 B2
Transversely-excited film bulk acoustic resonators with multiple piezoelectric membrane thicknesses on the same chip
Andrew Kay, Provo, UT (US); Patrick Turner, San Bruno, 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 Jun. 4, 2021, as Appl. No. 17/339,841.
Claims priority of provisional application 63/144,981, filed on Feb. 3, 2021.
Prior Publication US 2022/0247373 A1, Aug. 4, 2022
Int. Cl. H03H 9/54 (2006.01); H03H 3/02 (2006.01); H03H 9/02 (2006.01); H03H 9/13 (2006.01); H03H 9/17 (2006.01); H03H 9/205 (2006.01); H03H 9/56 (2006.01)
CPC H03H 9/54 (2013.01) [H03H 3/02 (2013.01); H03H 9/02015 (2013.01); H03H 9/02157 (2013.01); H03H 9/02228 (2013.01); H03H 9/13 (2013.01); H03H 9/174 (2013.01); H03H 9/205 (2013.01); H03H 9/564 (2013.01); H03H 9/568 (2013.01); H03H 2003/023 (2013.01); Y10T 29/42 (2015.01)] 20 Claims
OG exemplary drawing
 
1. A method for fabricating an acoustic filter with multiple piezoelectric plate thicknesses on a single chip, comprising:
forming conductor patterns on a piezoelectric plate;
bonding the piezoelectric plate to a sacrificial substrate, with the conductor patterns facing the sacrificial substrate;
thinning the piezoelectric plate to a first thickness for shunt resonators;
applying a mask and further thinning selected areas of the piezoelectric plate to a second thickness for series resonators to form a thinned piezoelectric plate;
bonding a substrate with a plurality of cavities to the thinned piezoelectric plate; and
removing the sacrificial substrate.