US 12,413,199 B2
Acoustic wave device, filter, multiplexer, and manufacturing method of acoustic wave device
Tasuku Kawashima, Tokyo (JP); Mamoru Ishida, Tokyo (JP); and Ryo Iwaki, Tokyo (JP)
Assigned to TAIYO YUDEN CO., LTD., Tokyo (JP)
Filed by TAIYO YUDEN CO., LTD., Tokyo (JP)
Filed on Sep. 29, 2022, as Appl. No. 17/956,481.
Claims priority of application No. 2021-161094 (JP), filed on Sep. 30, 2021; and application No. 2022-138121 (JP), filed on Aug. 31, 2022.
Prior Publication US 2023/0095992 A1, Mar. 30, 2023
Int. Cl. H03H 9/02 (2006.01); H03H 3/02 (2006.01); H03H 9/17 (2006.01)
CPC H03H 9/02086 (2013.01) [H03H 3/02 (2013.01); H03H 9/173 (2013.01); H03H 2003/021 (2013.01); H03H 2003/023 (2013.01)] 9 Claims
OG exemplary drawing
 
1. An acoustic wave device comprising:
a substrate;
a lower electrode and an upper electrode provided over the substrate;
a piezoelectric film that is provided over the substrate, at least a part of the piezoelectric film being interposed between the lower electrode and the upper electrode thereby defining a resonance region in a plan view where the lower electrode and the upper electrode overlap with each other across said at least a part of the piezoelectric film, the piezoelectric film having a pair of through holes, the pair of through holes sandwiching the resonance region therebetween in a first direction in the plan view, being provided along the resonance region, and being connected to an air gap, the air gap being formed between the substrate and the lower electrode and overlapping with the resonance region in the plan view; and
additional films that are not provided in a central region of the resonance region in the plan view and that are not provided in entire respective first edge regions, which are located on respective sides of the central region in the first direction in the plan view, of the resonance region, the additional film being provided in respective second edge regions, which are located on respective sides of the central region in a second direction substantially orthogonal to the first direction in the plan view, of the resonance region.