US 11,811,391 B2
Transversely-excited film bulk acoustic resonator with etched conductor patterns
Patrick Turner, San Bruno, CA (US); and Ryo Wakabayashi, Santa Clara, CA (US)
Assigned to MURATA MANUFACTURING CO., LTD., Nagaokakyo (JP)
Filed by Murata Manufacturing Co., Ltd., Nagaokakyo (JP)
Filed on Nov. 7, 2020, as Appl. No. 17/092,216.
Claims priority of provisional application 63/019,749, filed on May 4, 2020.
Prior Publication US 2021/0344317 A1, Nov. 4, 2021
Int. Cl. H03H 9/17 (2006.01); H03H 3/02 (2006.01); H03H 9/02 (2006.01); H03H 9/13 (2006.01); H03H 9/56 (2006.01); H03H 9/205 (2006.01); H03H 9/54 (2006.01); H10N 30/06 (2023.01)
CPC H03H 9/174 (2013.01) [H03H 3/02 (2013.01); H03H 9/02015 (2013.01); H03H 9/02031 (2013.01); H03H 9/02228 (2013.01); H03H 9/132 (2013.01); H03H 9/176 (2013.01); H03H 9/205 (2013.01); H03H 9/547 (2013.01); H03H 9/562 (2013.01); H03H 9/564 (2013.01); H03H 9/568 (2013.01); H10N 30/06 (2023.02); H03H 2003/023 (2013.01); Y10T 29/42 (2015.01); Y10T 29/49005 (2015.01)] 9 Claims
OG exemplary drawing
 
1. A method of fabricating an acoustic resonator device comprising:
forming a patterned first photoresist mask on a front surface of a single-crystal piezoelectric plate at locations of a desired IDT pattern;
blanket depositing an etch-stop layer on the front surface of the single-crystal piezoelectric plate where the patterned first photoresist mask does not exist and on the patterned first photoresist mask;
removing the patterned first photoresist mask and the etch-stop layer on the patterned first photoresist mask to expose the front surface of the piezoelectric plate at locations of the desired IDT pattern;
blanket depositing a conductor material on the etch stop layer and on the exposed front surface of the piezoelectric plate;
forming a patterned second photoresist mask on the conductor material at locations of the desired IDT pattern;
using an etch process to remove portions of the conductor material over and to the etch-stop layer to form an interdigital transducer (IDT) with the desired IDT pattern, the desired IDT pattern having interleaved fingers disposed on a diaphragm configured to span a cavity in a substrate supporting the piezoelectric plate, a portion of the piezoelectric plate and the etch-stop layer forming the diaphragm, wherein the etch-stop layer and the second photoresist mask are impervious to the etch process; and
removing the patterned second photoresist mask from the IDT to leave the IDT with the desired IDT pattern.