US 12,081,197 B2
Film bulk acoustic resonator and fabrication method thereof, filter, and radio frequency communication system
Huan Sui, Ningbo (CN); Fei Qi, Ningbo (CN); and Guohuang Yang, Ningbo (CN)
Filed by Ningbo Semiconductor International Corporation, Ningbo (CN)
Filed on Mar. 11, 2021, as Appl. No. 17/198,698.
Application 17/198,698 is a continuation of application No. PCT/CN2020/099647, filed on Jul. 1, 2020.
Claims priority of application No. 201910657139.6 (CN), filed on Jul. 19, 2019.
Prior Publication US 2021/0281243 A1, Sep. 9, 2021
Int. Cl. H03H 9/56 (2006.01); H03H 3/02 (2006.01); H03H 9/05 (2006.01); H03H 9/13 (2006.01); H03H 9/17 (2006.01)
CPC H03H 9/56 (2013.01) [H03H 3/02 (2013.01); H03H 9/0504 (2013.01); H03H 9/13 (2013.01); H03H 9/17 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A film bulk acoustic resonator, comprising:
a first substrate and a support layer disposed on the first substrate, wherein a cavity is formed in the support layer;
a piezoelectric stacked layer covering the cavity, wherein the piezoelectric stacked layer includes a first electrode, a piezoelectric layer, and a second electrode which are sequentially disposed on the support layer, and the piezoelectric stacked layer includes an active resonance region above a center of the cavity and an inactive resonance region surrounding the active resonance region; and
at least two trenches, arranged at a junction of the active resonance region and the inactive resonance region to define a range of the active resonance region, wherein the at least two trenches include a first trench and a second trench; the second trench passes through the second electrode layer and the piezoelectric layer; and the first trench passes the first electrode and the piezoelectric layer and is connected to the cavity, wherein:
an angle between a sidewall of the first trench and a plane of the second electrode is an obtuse angle, and an angle between a sidewall of the second trench and a plane of the first electrode is an obtuse angle.