A method for fabricating an array of front ends for an array of packaged electronic components that each comprise: an electrical element packaged within a package comprising a front part of a package comprising an inner section with a cavity therein opposite the resonator defined by the raised frame and an outer section sealing said cavity; and a back part of the package comprising a back cavity in an inner back section, and an outer back section sealing the cavity, said back package further comprising a first and a second via through the back end around said at least one back cavity for coupling to front and back electrodes of the electronic component; the vias terminating in external contact pads that are coupleable in a ‘flip chip’ configuration to a circuit board; the method comprising the stages of: i. Obtaining a carrier substrate having an active membrane layer attached thereto by its rear surface, with a front electrode on the front surface of the active membrane layer; ii. Obtaining an inner front end section; iii. Attaching the inner front end section to the exposed front surface of the front electrode; iv. Detaching the carrier substrate from the rear surface of the active membrane layer; v. Optionally thinning the inner front section; vi. Processing the rear surface by removing material to create an array of at least one island of active membrane on at least one island of front electrode; vii. Creating an array of at least one front cavity by selectively removing at least outer layer of the inner front end section, such that there is one cavity opposite each island of membrane on the front side of the front electrode on the opposite side to the island of active membrane; viii. Applying an outer front end section to the inner front end section and bonding the outer front end section to an outer surface of the inner front end section such that the outer front end section spans across and seals the at least one cavity of the array of front cavities.

A method and structure for a transfer process for an acoustic resonator device. In an example, a bulk acoustic wave resonator (BAWR) with an air reflection cavity is formed. A piezoelectric thin film is grown on a crystalline substrate. One or more patterned electrodes are deposited on the surface of the piezoelectric film. An etched sacrificial layer is deposited over the one or more electrodes and a planarized support layer is deposited over the sacrificial layer. The support layer is etched to form one or more cavities overlying the electrodes to expose the sacrificial layer. The sacrificial layer is etched to release the cavities around the electrodes. Then, a cap layer is fusion bonded to the support layer to enclose the electrodes in the support layer cavities.

A stacked-die oscillator package includes an oscillator circuit die having inner bond pads, and outer bond pads, and a bulk acoustic wave (BAW) resonator die having a piezoelectric transducer with a first and second BAW bond pad on a same side coupled to a top and bottom electrode layer across a piezoelectric layer. A first metal bump is on the first BAW bond pad and a second metal bump is on the second BAW bond pad flip chip bonded to the inner bond pads of the oscillator circuit die. A polymer material is in a portion of a gap between the BAW and oscillator circuit die.

Filter devices. A first chip includes a first interdigital transducer (IDT) of a first acoustic resonator formed on a surface of a first piezoelectric wafer having a first thickness, interleaved fingers of the first IDT disposed on a portion of the first piezoelectric wafer spanning a first cavity in a first base. A second chip includes a second IDT of a second acoustic resonator formed on a surface of a second piezoelectric wafer having a second thickness less than the first thickness, interleaved fingers of the second IDT disposed on a portion of the second piezoelectric wafer spanning a second cavity in a second base. A circuit card coupled to the first chip and the second chip includes at least one conductor for making an electrical connection between the first IDT and the second IDT.

A front-end module (FEM) for a 6.1 GHz Wi-Fi acoustic wave resonator RF filter circuit. The device can include a power amplifier (PA), a 6.1 GHz resonator, and a diversity switch. The device can further include a low noise amplifier (LNA). The PA is electrically coupled to an input node and can be configured to a DC power detector or an RF power detector. The resonator can be configured between the PA and the diversity switch, or between the diversity switch and an antenna. The LNA may be configured to the diversity switch or be electrically isolated from the switch. Another 6.1 GHZ resonator may be configured between the diversity switch and the LNA. In a specific example, this device integrates a 6.1 GHz PA, a 6.1 GHZ bulk acoustic wave (BAW) RF filter, a single pole two throw (SP2T) switch, and a bypassable LNA into a single device.

A 3D integrated circuit (3D IC) chip is described. The 3D IC chip includes a die having a compound semiconductor high electron mobility transistor (HEMT) active device. The compound semiconductor HEMT active device is composed of compound semiconductor layers on a single crystal, compound semiconductor layer. The 3D IC chip also includes an acoustic device integrated in the single crystal, compound semiconductor layer. The 3D IC chip further includes a passive device integrated in back-end-of-line layers of the die on the single crystal, compound semiconductor layer.

A bulk acoustic wave (BAW) structure includes a single crystal piezoelectric material layer, a first electrode, a second electrode and an acoustic reflector. The first and second electrodes are respectively located on a first surface and a second surface of the single crystal piezoelectric material layer. The area of the second electrode is greater than or equal to that of the second surface of the single crystal piezoelectric material layer, and the contact area of the single crystal piezoelectric material layer with the second electrode is equal to the area of the second surface of the single crystal piezoelectric material layer. The acoustic reflector is disposed on a surface of the first electrode.

Acoustic filters are disclosed. A bandpass filter has a passband between a lower band edge and an upper band edge. The bandpass filter includes a plurality of transversely-excited film bulk acoustic resonators (XBARs) connected in a ladder filter circuit. The plurality of XBARs includes at least one lithium tantalate XBAR and at least one lithium niobate XBAR.

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.

In a piezoelectric resonator device according to one or more embodiments, an internal space for hermetically sealing a vibrating part including a first excitation electrode and a second excitation electrode of a crystal resonator plate is formed by bonding a first sealing member and a second sealing member respectively to the crystal resonator plate. A through hole is formed in the second sealing member. A through electrode is formed along an inner wall surface of the through hole to establish conduction between an electrode formed on a first main surface and an external electrode terminal formed on a second main surface. A corrosion resistance structure to solder is formed on the through electrode that establishes conduction between the electrode and the external electrode terminal with a conductive metal other than Au.