US 12,294,343 B2
Cavity-type film bulk acoustic wave resonator without a sacrificial layer and a construction method thereof
Yao Shuai, Sichuan (CN); Chuangui Wu, Sichuan (CN); and Wenbo Luo, Sichuan (CN)
Assigned to UNIVERSITY OF ELECTRONIC SCIENCE AND TECHNOLOGY OF CHINA, Sichuan (CN)
Appl. No. 17/438,885
Filed by UNIVERSITY OF ELECTRONIC SCIENCE AND TECHNOLOGY OF CHINA, Sichuan (CN)
PCT Filed Nov. 13, 2019, PCT No. PCT/CN2019/118090
§ 371(c)(1), (2) Date Sep. 13, 2021,
PCT Pub. No. WO2020/181816, PCT Pub. Date Sep. 17, 2020.
Claims priority of application No. 201910187249.0 (CN), filed on Mar. 13, 2019.
Prior Publication US 2022/0149803 A1, May 12, 2022
Int. Cl. H03H 3/02 (2006.01); H03H 9/02 (2006.01); H03H 9/17 (2006.01)
CPC H03H 3/02 (2013.01) [H03H 9/02015 (2013.01); H03H 9/173 (2013.01); H03H 2003/021 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A method for constructing a cavity-type film bulk acoustic wave resonator without making a sacrificial layer, said method comprising the following steps:
(1) using an ion-implanted piezoelectric single crystal wafer with a bottom electrode, and forming a cavity on a bottom electrode side of the piezoelectric single crystal wafer; using a substrate and providing a bonded intermediate by bonding the substrate to a cavity side of the piezoelectric single crystal wafer by step (a):
(a) applying a bonding compound to one side of the substrate and bonding the substrate to the cavity side of the piezoelectric single crystal wafer; wherein the bonding compound is at least one organic insulating material selected from the group consisting of benzocyclobutene, polyimide, silsesquioxane and spin-on glass, wherein the bonding compound is applied by spin coating to form a bonding layer; the spin coating includes a low rotation speed phase and a high rotation speed phase; the low rotation speed phase having a rotation speed of 200 rpm/s-800 rpm/s and a rotation time of 10 s-30 s; and the high rotation speed phase having a rotation speed of 1,000 rpm/s-8,000 rpm/s, and a rotation time of 15 s-60 s; and
(2) performing heat treatment on the bonded intermediate obtained in step 1, peeling off a film from the piezoelectric single crystal wafer and generating a top electrode at a film-peeling side.