US 7,545,077 B2
Filter having multiple piezoelectric thin-film resonators
Shinji Taniguchi, Kawasaki (Japan); Tsuyoshi Yokoyama, Kawasaki (Japan); Motoaki Hara, Kawasaki (Japan); Takeshi Sakashita, Kawasaki (Japan); Jun Tsutsumi, Kawasaki (Japan); Masafumi Iwaki, Kawasaki (Japan); Tokihiro Nishihara, Kawasaki (Japan); Masanori Ueda, Kawasaki (Japan); and Hisanori Ehara, Yokohama (Japan)
Assigned to Fujitsu Media Devices Limited, Yokohama (Japan); and Fujitsu Limited, Kawasaki (Japan)
Filed on May 30, 2007, as Appl. No. 11/806,129.
Claims priority of application No. 2006-151474 (JP), filed on May 31, 2006.
Prior Publication US 2007/0279154 A1, Dec. 06, 2007
Int. Cl. H03H 9/00 (2006.01); H01L 41/08 (2006.01)
U.S. Cl. 310—320  [310/371; 333/187; 333/189] 14 Claims
OG exemplary drawing
 
1. A filter comprising multiple piezoelectric thin-film resonators each having a substrate, a lower electrode formed on the substrate, a piezoelectric film formed on the lower electrode, and an upper electrode provided on the piezoelectric film so that the upper electrode and the lower electrode face each other across the piezoelectric film,
the multiple piezoelectric thin-film resonators including a first resonator in which at least a part of an outer curved portion of the piezoelectric film of the first resonator is located further out than an outer curved portion of a region defined so that the upper electrode and the lower electrode face each other across the piezoelectric film,
the multiple piezoelectric thin-film resonators including a second resonator in which at least a part of an outer curved portion of the piezoelectric film of the second resonator substantially coincides with an outer curved portion of a region defined so that the upper electrode and the lower electrode face each other across the piezoelectric film or is further in than the outer curved portion of the region defined so that the upper electrode and the lower electrode face each other across the piezoelectric film.