A film bulk acoustic resonator (FBAR) structure includes a bottom cap wafer, a piezoelectric layer disposed on the bottom cap wafer, a bottom electrode disposed below the piezoelectric layer, and a top electrode disposed above the piezoelectric layer. Portions of the bottom electrode, the piezoelectric layer, and the top electrode that overlap with each other constitute a piezoelectric stack. The FBAR structure further includes a lower cavity disposed below the piezoelectric stack. A projection of the piezoelectric stack is located within the lower cavity.

A resonator that includes a vibrating portion that has a piezoelectric film, and a lower and upper electrodes that face each other with the piezoelectric film interposed therebetween. Moreover, a holding portion is provided at least around a maximum displacement region of the vibrating portion and has an insulating film. A holding arm connects the vibrating portion and the holding portion, and include a conductive portion that is in contact with the insulating film of the holding portion in at least a region that faces the maximum displacement region of the vibrating portion. In addition, the conductive portion is electrically connected to the lower electrode or the upper electrode or is grounded.

A method of manufacture for an acoustic resonator or filter device. In an example, the present method can include forming metal electrodes with different geometric areas and profile shapes coupled to a piezoelectric layer overlying a substrate. These metal electrodes can also be formed within cavities of the piezoelectric layer or the substrate with varying geometric areas. Combined with specific dimensional ratios and ion implantations, such techniques can increase device performance metrics. In an example, the present method can include forming various types of perimeter structures surrounding the metal electrodes, which can be on top or bottom of the piezoelectric layer. These perimeter structures can use various combinations of modifications to shape, material, and continuity. These perimeter structures can also be combined with sandbar structures, piezoelectric layer cavities, the geometric variations previously discussed to improve device performance metrics.

A bulk acoustic wave (BAW) resonator includes a solidly mounted reflector, for example, a Bragg-type reflector, a piezoelectric layer, and first and second electrodes on first and second surfaces, respectively, of the piezoelectric layer. A filter device or filter system includes at least one BAW resonator. Related methods of fabrication include forming the BAW resonator.

A piezoelectric vibrating device according to the present invention is provided with: a piezoelectric vibration plate having first and second driving electrodes respectively formed on main surfaces on both sides thereof, the piezoelectric vibration plate further having first and second mounting terminals that are respectively connected to the first and second driving electrodes. The piezoelectric vibrating device is also provided with first and second sealing members respectively joined to the main surfaces on both sides of the piezoelectric vibration plate in a manner that the first and second driving electrodes of the piezoelectric vibration plate are covered with these sealing members. At least one of the first and second sealing members includes a film made of a resin.

An AT-cut crystal vibration plate has, at its both ends, first and second castellations that interconnect first mounting terminals and also interconnect second mounting terminals formed on main surfaces on both sides of this plate. The first and second castellations respectively have first and second cutouts, and these cutouts each have an end surface extending along Z′ axis of crystal and located on a −X-axis side. The end surfaces each include a first inclined face inclined in a manner that protrudes from one of the main surfaces toward the −X-axis side, and a second inclined face inclined in a manner that protrudes from the other main surface toward the −X-axis side. The angle made by the first inclined face and the second inclined face is an obtuse angle.

Acoustic resonator devices and filters are disclosed. An acoustic resonator chip includes a piezoelectric plate attached to a substrate, a portion of the piezoelectric plate forming a diaphragm spanning a cavity in the substrate. A first conductor pattern formed on a surface of the piezoelectric plate includes interleaved fingers of an interdigital transducer on the diaphragm and a first plurality of contact pads. A second conductor pattern is formed on a surface of an interposer, the second conductor pattern including a second plurality of contact pads. Each pad of the first plurality of contact pads is directly connected to a respective pad of the second plurality of contact pads. A seal is formed between a perimeter of the piezoelectric plate and a perimeter of the interposer.

Methods of making acoustic resonator devices and filters are disclosed. A method of fabricating an acoustic resonator device includes fabricating an acoustic resonator chip including: attaching a back surface of a piezoelectric plate to a front surface of a substrate, such that portions of the piezoelectric plate form at least first and second diaphragms spanning at least first and second cavities, and forming a first conductor pattern as one or more conductor layers on the piezoelectric plate. The first conductor pattern includes at least first and second interdigitated transducers (IDTs) and a first plurality of contact pads. The method further includes fabricating an interposer having front and back surface and a second plurality of contact pads on the interposer back surface, forming conductive balls, and bonding each of the first plurality of contact pads to a respective pad of the second plurality of contact pads using the respective conductive ball.

A quartz crystal unit that includes a quartz crystal resonator with a quartz crystal blank on which a pair of excitation electrodes are formed, a frame body that surrounds an outer periphery of the blank, and a coupling member that couples the frame body to the blank. Moreover, a package member is joined to an entire periphery of the frame body on at least one side of the excitation electrodes; and an extension electrode is provided that is electrically connected to one of the excitation electrodes. A recess is formed in a junction region of at least one of the frame body and the package member. In the junction region, the extension electrode is disposed in the recess in such a way that the extension electrode has a thickness that does not exceed a depth of the recess.

A method for manufacturing a vibrator that includes forming excitation electrodes, lead-out electrodes, and first sealing frames on the main surfaces of a crystal piece; forming second sealing frames on the main surfaces of a base part and a lid part; and sealing a crystal vibration element by bonding the first sealing frames to the second sealing frames. The first sealing frames each include a first Ti or Cr base layer 110, and a first Au surface layer. The first Ti or Cr base layers are thinner than the first Au surface layers. The second sealing frames each include a second Ni base layer, and a second AuSn surface layer. The second Ni base layers are thicker than the second AuSn surface layers. The sealing is carried out by alloying the first Au surface layers and the second AuSn surface layers to each other.