Design and processes are described for fabricating single-crystal bulk acoustic wave resonators with better performance and better manufacturability. A low-acoustic-loss single-crystal piezoelectric layer is epitaxially grown on a substrate, followed with the formation of bottom electrode, metallic cavity frames, and gap filler material on the piezoelectric layer. Matching metallic cavity frames and gap filler material are formed on a second substrate. The two wafers are then bonded together by metal-to-metal bonding of the metallic cavity frames on the first wafer to the matching metallic cavity frame on the second wafer to form a sealed cavity between the bottom electrodes and the second wafer. The first substrate is then removed to expose the piezoelectric layer. This second wafer and the structures thereon are then ready to complete the BAW resonator and filter fabrication using standard wafer processing steps.

An acoustic wave device includes an acoustic wave substrate including a first main surface and a second main surface, IDT electrodes provided on the first main surface, and sealing resin covering at least the second main surface of the acoustic wave substrate. A hollow is provided in a region where the IDT electrodes on the first main surface of the acoustic wave substrate is located. The sealing resin has through-holes each extending from a top surface 13B of the sealing resin to the second main surface of the acoustic wave substrate. The acoustic wave substrate is made of silicon or includes a layer made of silicon.

An acoustic wave device includes a support substrate, a piezoelectric body layer, an interdigital transducer electrode, and an external connection electrode. The piezoelectric body layer is on the support substrate. The interdigital transducer electrode is on the piezoelectric body layer. The external connection electrode is electrically connected to the interdigital transducer electrode. The external connection electrode does not overlap the piezoelectric body layer in a plan view from a thickness direction of the support substrate. The support substrate includes a hollow portion. The hollow portion is at least on an end portion of the support substrate in a plan view from the thickness direction.

An electronic component includes: a first substrate; a second substrate that includes a functional element formed on a lower surface of the second substrate, the second substrate being mounted on the first substrate so that the functional element faces an upper surface of the first substrate across an air gap; and an insulating film that is located on the upper surface of the first substrate, overlaps with at least a part of the functional element in plan view, faces the functional element across the air gap, and has a film thickness that is more than half of a distance between a lower surface of the functional element and the upper surface of the first substrate.

In one aspect of the disclosure, a semiconductor package is disclosed. The semiconductor package includes a lead frame. A semiconductor die is attached to a first side of the lead frame. A protective shell covers at least a first portion of the first surface of the semiconductor die. The protective shell comprises of ink residue. A layer of molding compound covers an outer surface of the protective shell and exposed portion of the first surface of the semiconductor die. A cavity space is within an inner space of the protective shell and the first portion of the top surface of the semiconductor die.

A ceramic electronic component includes an electronic component body and portions of first and second metal terminals defined by lead wires covered with an outer resin material. The first metal terminal includes, connected in order, a first terminal joint portion, a first extension portion extending in a direction toward a mounting surface, and a first mount portion extending toward a side opposite to the electronic component body. The second metal terminal includes, connected in order, a second terminal joint portion, a second extension portion extending in the direction toward the mounting surface, and a second mount portion extending toward a side opposite to the electronic component body. The first and second mount portions respectively include first and second protruding bending portions protruding toward the mounting surface. The outer resin material includes a protruding portion protruding toward the mounting surface.

In one aspect of the disclosure, a semiconductor package is disclosed. The semiconductor package includes a lead frame. A semiconductor die is attached to a first side of the lead frame. A protective shell covers at least a first portion of the first surface of the semiconductor die. The protective shell comprises of ink residue. A layer of molding compound covers an outer surface of the protective shell and exposed portion of the first surface of the semiconductor die. A cavity space is within an inner space of the protective shell and the first portion of the top surface of the semiconductor die.

An acoustic wave device includes a piezoelectric substrate, a first band pass filter that is on the piezoelectric substrate and has a first pass band, and a second band pass filter that is on the piezoelectric substrate and has a second pass band at a higher frequency than the first pass band. The first and second band pass filters include resonators that include respective IDT electrodes. When a first total average metallization ratio is defined as an average of metallization ratios of all of the IDT electrodes included in the first filter and a second total average metallization ratio is defined as an average of metallization ratios of all of the IDT electrodes included in the second filter, the first total average metallization ratio is greater than the second total average metallization ratio.

A film bulk acoustic wave resonator (BAWR) includes a first substrate; a first insulating material layer; and a first cavity, formed in the first insulating material layer. The film BAWR also includes a first electrode containing a first electrode cavity; a second electrode containing a second electrode cavity; and a first piezoelectric oscillation plate, sandwiched between the first electrode and the second electrode. Without having any parallel edges, the boundary of the first piezoelectric oscillation plate is entirely enclosed in the first cavity boundary, and at least includes an overlapping region of the boundary of the first electrode cavity and the boundary of the second electrode cavity. The film BAWR further includes a plurality of second and third piezoelectric oscillation plates, disposed between the first electrode and the second electrode to receive and absorb vibration energy transmitted out through vibration waves induced in the first electrode and the second electrode.

A clock oscillator, a clock oscillator production method and use method, and a chip including the clock oscillator are provided. The clock oscillator includes a resonator, a shock-absorbing material layer, and a base, and at least a part of the shock-absorbing material layer is located between the resonator and the base. In the clock oscillator, the shock-absorbing material layer is added between the resonator and the base, and the shock-absorbing material layer can effectively prevent a mechanical wave from being conducted between the base and the resonator, so that the resonator is protected from external vibration. This can ensure, when there is external vibration, that an output frequency of the resonator is not deteriorated and improve shock absorption performance of the clock oscillator.