US 12,334,904 B2
Bulk acoustic wave filter having release hole and fabricating method of the same
Jian Wang, Shenzhen (CN)
Assigned to Shenzhen Newsonic Technologies Co., Ltd., Shenzhen (CN)
Filed by Shenzhen Newsonic Technologies Co., Ltd., Shenzhen (CN)
Filed on Jun. 21, 2022, as Appl. No. 17/807,940.
Prior Publication US 2022/0321094 A1, Oct. 6, 2022
Int. Cl. H03H 9/17 (2006.01); H03H 3/02 (2006.01); H03H 9/13 (2006.01); H03H 9/54 (2006.01)
CPC H03H 9/172 (2013.01) [H03H 3/02 (2013.01); H03H 9/131 (2013.01); H03H 9/54 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A bulk acoustic wave resonator, comprising:
a substrate;
a support layer disposed on the substrate, the support layer including a cavity having a polygon shape with more than three sides in a plane crossing a first direction from the substrate to the support layer;
a piezoelectric layer disposed on the support layer;
a bottom electrode disposed below the piezoelectric layer, partially overlapping the cavity, and extending across a first side of the cavity;
a top electrode disposed above the piezoelectric layer, partially overlapping the cavity, and extending across a second side of the cavity;
at least one release hole formed in the piezoelectric layer and overlapping a portion of the cavity, the at least one release hole including at least one of:
a first release hole located adjacent to a side of the cavity that is different from the first side and the second side;
a second release hole located adjacent to the first side of the cavity, and overlapping the bottom electrode; or
a third release hole located adjacent to the second side of the cavity, and overlapping the top electrode;
a bonding layer disposed between the substrate and the support layer and including a protruding structure; and
a boundary layer overlying the bonding layer,
wherein at least a portion of the boundary layer is formed between the protruding structure and the bottom electrode.