US 12,074,586 B2
Structure and manufacturing method of surface acoustic wave filter with back electrode of piezoelectric layer
Guojun Weng, Shenzhen (CN); and Gongbin Tang, Shenzhen (CN)
Assigned to Shenzhen Newsonic Technologies Co., Ltd., Shenzhen (CN)
Filed by Shenzhen Newsonic Technologies Co., Ltd., Shenzhen (CN)
Filed on Sep. 16, 2022, as Appl. No. 17/933,070.
Prior Publication US 2023/0188116 A1, Jun. 15, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. H03H 9/64 (2006.01); H03H 3/08 (2006.01); H03H 9/02 (2006.01); H03H 9/05 (2006.01); H03H 9/10 (2006.01)
CPC H03H 9/6423 (2013.01) [H03H 3/08 (2013.01); H03H 9/02897 (2013.01); H03H 9/059 (2013.01); H03H 9/1092 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A surface acoustic wave (SAW) filter, comprising:
a bottom substrate;
a piezoelectric layer disposed above the bottom substrate, the piezoelectric layer having a bottom surface facing the bottom substrate and a top surface opposite to the bottom surface;
a lower cavity disposed below the piezoelectric layer;
an interdigital transducer (IDT) disposed on the top surface of the piezoelectric layer; and
a back electrode disposed on the bottom surface of the piezoelectric layer,
wherein the back electrode includes a first surface facing the piezoelectric layer, a second surface facing the bottom substrate, and a side surface connecting the first surface and a second surface, and
at least a portion of the side surface of the back electrode is exposed in the lower cavity.