a SAW filter includes a substrate including a piezoelectric substrate, a transmission filter, and an additional resonator. The transmission filter is a ladder-type filter filtering signals from a transmission terminal and outputting the result to an antenna terminal. Further, the transmission filter includes one or more serial resonators and one or more parallel resonators which are connected in a ladder configuration on the piezoelectric substrate. An initial stage resonator is the serial resonator. The additional resonator includes an IDT electrode on the piezoelectric substrate. The IDT electrode is connected to the transmission terminal at a stage before the transmission filter and is connected to any of the one or more GND terminals. In the additional resonator, a resonance frequency and an antiresonance frequency are located outside of a passband of the transmission filter.

A manufacturing method of a mounting structure, the method including: a step of preparing a mounting member including a first circuit member and a plurality of second circuit members placed on the first circuit member, the mounting member having a space between the first circuit member and the second circuit member; a step of preparing a laminate sheet including a first thermal-conductive layer and a second thermal-conductive layer, the first thermal-conductive layer disposed at least on one outermost side; a disposing step of disposing the laminate sheet on the mounting member such that the first thermal-conductive layer faces the second circuit members; and a sealing step of pressing the laminate sheet against the first circuit member and heating the laminate sheet, to seal the second circuit members so as to maintain the space, and to cure the laminate sheet. The first thermal-conductive layer after curing has a coefficient of thermal conductivity in a thickness direction at room temperature being equal to or greater than that in a principal surface direction, and the second thermal-conductive layer after curing has a coefficient of thermal conductivity in a principal surface direction at room temperature being greater than that in a thickness direction.

A manufacturing method of a mounting structure, the method including: a step of preparing a mounting member including a first circuit member and a plurality of second circuit members placed on the first circuit member; a step of preparing a sheet having thermosetting property; a disposing step of disposing the sheet on the mounting member so as to face the second circuit members; and a sealing step of pressing the sheet against the first circuit member and heating the sheet, to seal the second circuit members and to cure the sheet, wherein the second circuit members include a reference member, and a first adjacent member and a second adjacent member each adjacent to the reference member, a separation distance D1 between the reference member and the first adjacent member is different from a separation distance D2 between the reference member and the second adjacent member, at least one of the plurality of the second circuit members is a hollow member to be provided with a space from the first circuit member, and in the sealing step, the plurality of the second circuit members are sealed so as to maintain the space.

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 electronic component-containing module includes a board, electronic components, and a sealing resin and includes a space provided between the board and at least one of the electronic components. The dryness factor of the sealing resin is about 60% or more where, after the electronic component-containing module is moisturized, the electronic component-containing module is heated to the re-melting temperature of a brazing filler metal.

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 acoustic wave device includes a laminated film on a support substrate and inside a portion of an outer edge of the support substrate in plan view and including a piezoelectric thin film, an IDT electrode on the laminated film, an insulating layer on the support substrate and the laminated film and extending from a region above the support substrate to a region above the laminated film, a connecting electrode on the insulating layer and electrically connected to the IDT electrode, and an external connection terminal electrically connected to the connecting electrode and disposed directly on or above the connecting electrode and outside a region where the laminated film is on the support substrate. A principal surface of the support substrate on the laminated film side includes a recess at an outer edge of the laminated film, and the recess is covered with the insulating layer.

A manufacturing method for an electronic component includes forming an electrically conductive pillar on a surface of a support, forming an intermediate layer covering a side surface of the pillar, forming a conductor layer covering a side surface of the intermediate layer, and molding a resin structure covering a side surface of the conductor layer.

A bulk-acoustic resonator module includes: a module substrate; a bulk-acoustic resonator connected to the module substrate by a connection terminal and disposed spaced apart from the module substrate; and a sealing portion sealing the bulk-acoustic resonator. The bulk-acoustic resonator includes a resonating portion disposed opposite to an upper surface of the module substrate. A space is disposed between the resonating portion and the upper surface of the module substrate.

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.