US 11,990,889 B2
Bulk acoustic wave resonator and formation method thereof
Kuo-Lung Weng, Taoyuan (TW); Chia-Ta Chang, Taoyuan (TW); Tzu-Sheng Hsieh, Taoyuan (TW); and Chun-Ju Wei, Taoyuan (TW)
Assigned to WIN SEMICONDUCTORS CORP., Taoyuan (TW)
Filed by WIN SEMICONDUCTORS CORP., Taoyuan (TW)
Filed on Dec. 28, 2020, as Appl. No. 17/134,681.
Prior Publication US 2022/0209741 A1, Jun. 30, 2022
Int. Cl. H03H 9/17 (2006.01); H03H 3/02 (2006.01); H03H 9/02 (2006.01); H03H 9/13 (2006.01)
CPC H03H 9/172 (2013.01) [H03H 3/02 (2013.01); H03H 9/02015 (2013.01); H03H 9/131 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A bulk acoustic wave resonator, comprising:
a substrate;
a seed layer disposed on the substrate;
a bottom electrode disposed on the seed layer;
a piezoelectric layer disposed on the bottom electrode;
a top electrode disposed on the piezoelectric layer;
wherein the substrate has a cavity thereon, and the seed layer has an opening exposing a bottom surface of the bottom electrode and a portion of a bottom surface of the piezoelectric layer, and communicating with the cavity,
wherein the bulk acoustic wave resonator further comprising via holes disposed on a region of the cavity outside the bottom electrode and the top electrode, and the via holes are in communication with the cavity and the opening.