A bulk acoustic resonator includes: a substrate; a first electrode disposed on the substrate; a piezoelectric layer disposed to cover at least a portion of the first electrode; a second electrode disposed to cover at least a portion of the piezoelectric layer; a metal pad connected to the first electrode and the second electrode; and a protective layer disposed to cover at least the metal pad.

A quartz crystal resonator unit includes a quartz crystal substrate, first and second excitation electrodes, first and second conductive sealing members, and first and second exterior members. The first excitation electrode is disposed on a first main surface of the substrate with the first conductive sealing member surrounding the first excitation electrode. Similarly, the second excitation electrode is disposed on a second main surface of the substrate with the second conductive sealing surrounding the second excitation electrode. The first and second exterior members are bonded to the quartz crystal substrate with the first and second conductive sealing member respectively interposed therebetween and to cover the first and excitation electrodes, respectively. In a plan view of the first main surface of the substrate, at least part of the first conductive sealing member is located outward of the second conductive sealing member.

There is disclosed acoustic resonators and filter devices. An acoustic resonator device includes a piezoelectric plate, and an interdigital transducer (IDT) formed on a front surface of the piezoelectric plate. The IDT includes interleaved fingers. At least one of the interleaved fingers includes a first layer adjacent the piezoelectric plate and a second layer over the first layer, wherein a width of the first layer is constant, and wherein a width of the second layer varies along a length of the at least one interleaved finger.

A method of manufacturing a piezoelectric resonator unit that includes preparing a piezoelectric resonator having a piezoelectric element, a pair of excitation electrodes respectively disposed on a first main surface and a second main surface of the piezoelectric element so as to face each other with the piezoelectric element therebetween, and a pair of connection electrodes that are respectively electrically connected to the pair of excitation electrodes; electrically connecting the pair of connection electrodes to a pair of electrode pads on a third main surface of a base member using an electroconductive holding member so as to excitably hold the piezoelectric resonator on the third main surface of the base member; and attaching an electroconductive material, which is scattered from an electroconductive member, to a surface of the electroconductive holding member.

A quartz crystal resonator unit that includes: a piezoelectric blank; a first excitation electrode on a first principal surface and within at least a part of a vibration portion of the piezoelectric blank; a second excitation electrode on a second principal surface and within at least a part of the vibration portion of the piezoelectric blank; a first extended electrode on the first principal surface and electrically connected to the first excitation electrode; and a second extended electrode on the second principal surface and electrically connected to the second excitation electrode; and an insulation layer including a hollow portion which defines a space with the second excitation electrode. A thickness of the first extended electrode is larger than a thickness of the second extended electrode. An end portion of the first extended electrode extends over the hollow portion in a plan view of the piezoelectric vibrator.

Devices and processes for preparing devices are described for a bulk acoustic wave resonator. A stack includes a first electrode that is coupled to a first side of a piezoelectric layer and a second electrode that is coupled to a second side of the piezoelectric layer. The stack is configured to resonate in response to an electrical signal applied between the first electrode and the second electrode. A cavity frame is coupled to the first electrode and to the substrate. The cavity frame forms a perimeter around a cavity. Optionally, a heat dissipating frame is formed and coupled to the second electrode. The cavity frame and/or the heat dissipating frame improve the thermal stability of the bulk acoustic resonator.

An acoustic resonator includes a membrane layer disposed on an insulating layer; a cavity formed by the insulating layer and the membrane layer and having a hydrophobic layer disposed on at least one of a portion of an upper surface of the cavity and a portion of a lower surface of the cavity; and a resonating portion disposed on the cavity and having a second electrode on a piezoelectric layer on a first electrode.

In a crystal resonator plate (2), a support part (24) extends from only one corner part positioned in the +X direction and in the −Z′ direction of a vibrating part (22) to an external frame part (23) in the −Z′ direction. The vibrating part (22) and at least part of the support part (24) form an etching region (Eg) having a thickness thinner than a thickness of the external frame part (23). A stepped part is formed at a boundary of the etching region (Eg), and a first lead-out wiring (223) is formed over the support part (24) to the external frame part (23) so as to overlap with the stepped part. At least part of the stepped part that is superimposed on the first lead-out wiring (223) is formed so as not to be parallel to the X axis in plan view.

An apparatus and method for making an acoustic filter package where the apparatus includes a base layer; a support layer disposed on the base layer; a piezoelectric structure disposed on the support layer; wherein the piezoelectric structure comprises: a piezoelectric layer; a top electrode on a top surface of the piezoelectric layer; a bottom electrode on a bottom surface of the piezoelectric layer; a contact pad coupled to the bottom electrode that extends through an opening in the piezoelectric layer and is coupled to the bottom electrode or the top electrode; and a corrosion resistant pad disposed on the contact pad; and a capping structure disposed on the piezoelectric structure.

An electro-acoustic resonator comprises an acoustic mirror (120) disposed on a carrier substrate (110), a bottom electrode (130) and a piezoelectric layer (140). An aluminum seed layer (180) is disposed on the piezoelectric layer and a structured silicon dioxide flap layer (150) is disposed on the aluminum seed layer. The aluminum seed layer (180) increases the quality factor of the resonator and leads to enhanced RF filter performance.