The present disclosure provides a packaging method and packaging structure of an FBAR. A second cavity in a resonator cover provided includes a groove in a second substrate and a space surrounded by an elastic bonding material layer. The elastic bonding material layer bonds the resonator cover to a resonant cavity main structure, and elasticity of the elastic bonding material layer is removed after the bonding. Through holes and a conductive interconnection layer on inner surfaces of the through holes are formed on the resonator cover. Since the second cavity includes the groove in the second substrate and the space surrounded by the elastic bonding material layer, which can avoid problems that performance of the elastic bonding material layer is unstable with temperature and humidity changes when the second cavity is entirely surrounded by the elastic bonding material layer, that is, the stability of the resonator is improved.

A bulk acoustic wave resonator, a filter, and a radio frequency communication system are provided. The bulk acoustic wave resonator includes a substrate and a bottom electrode layer, where a cavity is formed therebetween. The bulk acoustic wave resonator also includes a piezoelectric layer formed on the bottom electrode layer and over the cavity, and a top electrode layer formed over the piezoelectric layer. At least one of the bottom electrode layer and the top electrode layer has a convex portion or concave portion. The convex portion is located in a region of the cavity and is protruded facing away from a bottom of the cavity, and the concave portion is located in the region of the cavity and is recessed towards the bottom of the cavity. Each of the convex portion and the concave portion is located in a peripheral region surrounding the piezoelectric layer.

The present disclosure provides a film bulk acoustic resonator and its fabrication method. The fabrication method includes providing a first substrate, and sequentially forming a first electrode layer, a piezoelectric material layer, and a second electrode layer, on the first substrate; forming a support layer on the second electrode layer and forming a cavity with a top opening in the support layer, where the cavity passes through the support layer; providing a second substrate and bonding the second substrate with the support layer; removing the first substrate; and patterning the first electrode layer, the piezoelectric material layer, and the second electrode layer to form a first electrode, a piezoelectric layer, and a second electrode.

An acoustic wave device includes a first substrate, a piezoelectric layer, a functional electrode on first and/or second main surfaces of the piezoelectric layer, a second substrate, and extraction electrodes. The extraction electrodes include a support portion supporting the second substrate, a through via penetrating the second substrate, a first land on a first main surface of the second substrate and electrically connected to the through via, and a second land on a second main surface of the second substrate and electrically connected to the through via. In at least one of the extraction electrodes, insulators are provided between the first main surface of the second substrate and the first land, between the second main surface of the second substrate and the second land, and between the side wall of the through via and the second substrate.

An acoustic wave device includes: a first substrate having a first surface and a side surface; an acoustic wave resonator located on the first surface of the first substrate; and a first insulator film that covers the acoustic wave resonator and is in contact with at least a part, which is located closer to the first surface, of the side surface of the first substrate.

A bulk acoustic wave (BAW) resonator includes: a substrate; an acoustic reflector disposed in the substrate; a first electrode disposed over the acoustic reflector; a second electrode; and a piezoelectric layer between the first and second electrodes. The second electrode is not disposed between the first electrode and the acoustic reflector. The BAW resonator further includes a block disposed over the substrate and beneath the piezoelectric layer. A contacting overlap of the acoustic reflector, the first electrode, the second electrode and the piezoelectric layer defines an active area of the BAW resonator.

A piezoelectric thin film resonator includes: a substrate; a piezoelectric film that is located on the substrate; a lower electrode that is located on the substrate through an air gap, makes contact with the piezoelectric film, and includes a thin film part and a thick film part in which a distance from the air gap to a surface making contact with the piezoelectric film is greater than that of the thin film part in a region overlapping with the air gap in plan view; and an upper electrode that is located on an opposite surface of the piezoelectric film from a surface making contact with the lower electrode.

A ladder-type filter includes: a first piezoelectric thin film resonator including a first lower electrode, a first piezoelectric film, a first upper electrode, and an insertion film inserted between the first lower and upper electrodes, the insertion film being located in an outer peripheral region of a first resonance region; a second piezoelectric thin film resonator including a second lower electrode, a second piezoelectric film, and a second upper electrode, the second piezoelectric thin film resonator having no insertion film between the second lower and upper electrodes in a second resonance region; a series resonator, at least one of the series resonator being a first resonator that is one of the first and second piezoelectric thin film resonators, and a parallel resonator, at least one of the parallel resonator being a second resonator that is another of the first and second piezoelectric thin film resonators.

An acoustic resonator and a method of manufacturing the same are provided. The acoustic resonator includes a resonance part including a first electrode, a second electrode, and a piezoelectric layer disposed between the first and second electrodes; and a substrate disposed below the resonance part. The piezoelectric layer is disposed on a flat surface of the first electrode.

A packaged resonator includes a substrate, an acoustic stack, a first polymer layer and a second polymer layer. The acoustic stack is disposed over the substrate. The first polymer layer is disposed over the substrate surrounding the acoustic stack. The first polymer layer also provides a first air gap above the acoustic stack. The second polymer layer is disposed over the acoustic stack and above the first air gap.