Disclosed is a film bulk acoustic resonator (FBAR) type filter including a substrate including two or more cavities on a top surface thereof, a lower electrode formed above the substrate, a piezoelectric layer formed above the lower electrode, two or more upper electrodes formed above the piezoelectric layer, and a package layer including a wall vertically extending while surrounding a periphery of certain areas in which the cavities and the lower electrode are formed and a roof disposed above the wall while being spaced apart from the upper electrodes to seal the certain areas.

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 elastic wave device manufacturing method includes a preparing a piezoelectric wafer on which IDT electrodes are provided in elastic wave device forming portions, providing on a first main surface of the piezoelectric wafer support layers in the elastic wave device forming portions, bonding a cover member to cover the support layers to obtain a multilayer body, cutting the multilayer body in a first direction multiple times, cutting the multilayer body in a second direction orthogonal to the first direction to obtain elastic wave devices, in which a resin layer extends across a boundary between the elastic wave device forming portions adjacent to each other on the first main surface of the piezoelectric wafer, and the second cutting step is performed in a state in which the resin layer is present.

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.

A high frequency module includes a mounting substrate, an acoustic wave filter, a protection member, a resin layer, and a shield layer. The acoustic wave filter is mounted on a first main surface of the mounting substrate. The protection member is disposed on a main surface of the acoustic wave filter that is far from the mounting substrate. The resin layer is disposed on the first main surface of the mounting substrate and covers an outer peripheral surface of the acoustic wave filter and an outer peripheral surface of the protection member. The shield layer covers the resin layer and the protection member. The protection member is in contact with both the acoustic wave filter and the shield layer. The acoustic wave filter includes a piezoelectric substrate. A main surface of the piezoelectric substrate that is far from the mounting substrate is in contact with the protection member.

An acoustic wave device includes an element substrate having piezoelectricity, an interdigital transducer electrode provided on the element substrate, and a mold resin covering the element substrate. When viewed in a cross section, the element substrate includes an interdigital transducer formation region in which the interdigital transducer electrode is provided and a pair of interdigital transducer non-formation regions in which the interdigital transducer electrode is not provided and located on both sides of the interdigital transducer formation region, and a thickness dimension of a center portion, in a width direction, of the interdigital transducer formation region is less than at least one of thickness dimensions of center portions, in the width direction, of the interdigital transducer non-formation regions.

A method for packaging chips includes: flip-chip bonding a plurality of filter chips to be packaged on a substrate to be packaged; applying a first mold material layer on the filter chips to be packaged; applying a second mold material layer on a side of the first mold material layer away from the filter chip to be packaged, the first mold material layer and the second mold material layer forming a first mold layer; thinning the first mold material layer and the second mold material layer to expose substrates of the filter chips to be packaged, and thinning the substrates of the filter chips to be packaged to a preset thickness; applying a second mold layer on the exposed substrates of the filter chips to be packaged to obtain a mold structure; and cutting the mold structure into a plurality of particle chips.

An electronic component may include a substrate having a functional unit formed on a main surface of the substrate and a first resin layer formed on the main surface, the first resin layer having a first surface facing the main surface and a second surface opposed to the first surface, the first resin layer defining a cavity on the first surface enclosing the functional unit, the first resin layer defining a recess on the second surface, and a solder layer being formed in the recess so as not to exceed the second surface in a thickness direction. The functional unit may include a surface acoustic wave (SAW) element or a film bulk acoustic resonator (FBAR) having a mechanically movable portion. The substrate may be formed of dielectric material.

A method for packaging chips includes: flip-chip bonding a plurality of filter chips to be packaged on a substrate to be packaged; applying a first mold material layer on the filter chips to be packaged; applying a second mold material layer on a side of the first mold material layer away from the filter chip to be packaged, the first mold material layer and the second mold material layer forming a first mold layer; thinning the first mold material layer and the second mold material layer to expose substrates of the filter chips to be packaged, and thinning the substrates of the filter chips to be packaged to a preset thickness; applying a second mold layer on the exposed substrates of the filter chips to be packaged to obtain a mold structure; and cutting the mold structure into a plurality of particle chips.

A package that includes a first filter device and a second filter device coupled to the first filter device. The first filter device includes a first substrate comprising a first piezoelectric material, and a first metal layer coupled to a first surface of the first substrate. The second filter device includes a second substrate comprising a second piezoelectric material, and a second metal layer coupled to a first surface of the first substrate. The package includes a first pillar interconnect configured to be electrically coupled to the first metal layer of the first filter device, where the first pillar interconnect extends through the second filter device. The package further includes a second pillar interconnect configured to be electrically coupled to the second metal layer of the second filter device.