An acoustic resonator is fabricated by forming a patterned first photoresist mask on a piezoelectric plate at locations of a desired interdigital transducer (IDT) pattern. An etch-stop layer is then deposited on the plate and first photoresist mask. The first photoresist mask is removed to remove parts of the etch-stop and expose the plate. An IDT conductor material is deposited on the etch stop and the exposed plate. A patterned second photoresist mask is then formed on the conductor material at locations of the IDT pattern. The conductor material is then etched over and to the etch-stop to form the IDT pattern which has interleaved fingers on a diaphragm to span a substrate cavity. A portion of the plate and the etch-stop form the diaphragm. The etch-stop and photoresist mask are impervious to this etch. The second photoresist mask is removed to leave the IDT pattern.

A seed layer (210) of a noble metal is formed by electrochemical deposition on a metal electrode (111) disposed on a dielectric layer (110,310). The noble metal seed layer allows the deposition of a highly textured piezoelectric layer (320) on the metal electrode.

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. A first patterned electrode is deposited on the surface of the piezoelectric film. An etched sacrificial layer is deposited over the first electrode and a planarized support layer is deposited over the sacrificial layer, which is then bonded to a substrate wafer. The crystalline substrate is removed and a second patterned electrode is deposited over a second surface of the film. The sacrificial layer is etched to release the air reflection cavity. Also, a cavity can instead be etched into the support layer prior to bonding with the substrate wafer. Alternatively, a reflector structure can be deposited on the first electrode, replacing the cavity.

A packaging method and a packaging structure of a film bulk acoustic resonator are provided. The packaging method includes: providing a resonant cavity main structure including a first substrate and a film bulk acoustic resonant structure having a first cavity formed therebetween; forming a resonator cover by providing a second substrate and forming an elastic bonding material layer containing a second cavity and an initial opening; bonding the resonant cavity main structure and the resonator cover together through the elastic bonding material layer and removing elasticity of the elastic bonding material layer, where the second cavity is at least partially aligned with the first cavity; forming a through-hole containing the initial opening and a hole connected with the initial opening and passing through the resonator cover; and forming a conductive interconnection layer covering a sidewall of the through-hole and a portion of a surface of the resonator cover.

Acoustic resonator devices and methods are disclosed. An acoustic resonator device includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces. An etch-stop layer is sandwiched between the surface of the substrate and the back surface of the piezoelectric plate, a portion of the piezoelectric plate and the etch-stop layer forming a diaphragm spanning a cavity in the substrate. An interdigital transducer (IDT) is formed on the front surface of the single-crystal piezoelectric plate with interleaved fingers of the IDT disposed on the diaphragm. The etch-stop layer is impervious to an etch process used to form the cavity. The etch-stop layer is a high thermal conductivity material selected from aluminum nitride, boron nitride, and diamond.

Acoustic resonator devices and methods are disclosed. An acoustic resonator device includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces. A back-side dielectric layer is formed on the back surface. An etch-stop layer is sandwiched between the surface of the substrate and the back-side dielectric layer. A portion of the piezoelectric plate, the back-side dielectric layer, and the etch-stop layer forms a diaphragm spanning a cavity in the substrate. An interdigital transducer (IDT) is formed on the front surface of the single-crystal piezoelectric plate with interleaved fingers of the IDT disposed on the diaphragm. The etch-stop layer is impervious to an etch process used to form the cavity.

Acoustic resonator devices and methods are disclosed. An acoustic resonator device includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces. A bonding layer is formed on the surface of the substrate. An etch-stop layer is sandwiched between the bonding layer and the back surface of the single crystal piezoelectric plate. A portion of the single crystal piezoelectric plate and the etch-stop layer, but not the bonding layer, forms a diaphragm spanning a cavity in the substrate. An interdigital transducer (IDT) is formed on the front surface of the single-crystal piezoelectric plate with interleaved fingers of the IDT disposed on the diaphragm. The etch-stop layer is impervious to an etch process used to form the cavity.

A package for an electronic component, the package comprising a front end, a back end, and an active membrane layer sandwiched between front and back electrodes of conducting material; wherein front electrode has a surface that extends beyond an adjacent surface of the active membrane layer, the active membrane mechanically supported by the front end and covered by a back end comprising at least one back cavity having organic walls and lid of organic material, with filled through vias traversing the organic walls and lid for coupling to the electrodes by an internal routing layer; the vias being coupleable by external solderable bumps to a circuit board for coupling the package in a flip chip configuration.

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. A first patterned electrode is deposited on the surface of the piezoelectric film. An etched sacrificial layer is deposited over the first electrode and a planarized support layer is deposited over the sacrificial layer, which is then bonded to a substrate wafer. The crystalline substrate is removed and a second patterned electrode is deposited over a second surface of the film. The sacrificial layer is etched to release the air reflection cavity. Also, a cavity can instead be etched into the support layer prior to bonding with the substrate wafer. Alternatively, a reflector structure can be deposited on the first electrode, replacing the cavity.

A film bulk acoustic resonator and a fabricating method thereof is provided. The fabricating method includes: fabricating a lower electrode on a first surface of an SOI substrate; forming piezoelectric layers on the first surface of the SOI substrate and the lower electrode; forming top electrodes on the piezoelectric layers; processing an air cavity on a second surface of the SOI substrate, wherein the second surface and the first surface are oppositely arranged. The fabricating method simplifies a preparation process of FBAR, a quality of a AlN film crystal grown though the fabrication method is high, an improvement of a device performance is facilitated, and meanwhile a thickness of a top silicon is controlled through a position of a silicon injected oxygen isolation to regulate a frequency of the film bulk acoustic resonator.