An elastic wave device includes a spacer layer on or above a support substrate and outside a piezoelectric film as seen in a plan view from a thickness direction of the support substrate. A cover layer is disposed on the spacer layer. A through electrode extends through the spacer layer and the cover layer and is electrically connected to the wiring electrode. The wiring electrode includes a first section overlapping the through electrode as seen in the plan view from the thickness direction, a second section overlapping the piezoelectric film as seen in the plan view from the thickness direction, and a step portion defining a step in the thickness direction between the first section and the second section. The spacer layer includes an end portion embedded in the cover layer.

An acoustic wave device includes a substrate, as well as a first electrode layer, a piezoelectric layer and a second electrode layer which are sequentially arranged on the substrate. The device further includes a protective layer. The protective layer is at least arranged at a first position above the surface, far away from the substrate, of the second electrode layer. The first position is a position, corresponding to a first overlapping region, above the second electrode layer. The first overlapping region, where an active area of the acoustic wave device is located, is at least a part of a region where the first electrode layer, the second electrode layer and the piezoelectric layer are overlapped. A fabrication method for an acoustic wave device is also provided.

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.

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 photosensitive resin composition according to the present invention is a photosensitive resin composition comprising (a) an alkali-soluble polyimide, (b) an unsaturated bond-containing compound, (c) a thermally crosslinkable compound, (d-1) a photobleaching photopolymerization initiator having the structure represented by general formula (1), and (d-2) a photopolymerization initiator having the structure represented by general formula (1) and having a molar extinction coefficient at a wavelength of 405 nm of at least 1000 L/(mol.Math.cm). (In general formula (1), R.sup.1 represents a halogen atom, hydroxy group, carboxy group, nitro group, cyano group, —NR.sup.3R.sup.4, C1-20 monovalent hydrocarbon group, C1-20 acyl group, or C1-20 alkoxy group, and R.sup.3 and R.sup.4 each independently represent a hydrogen atom or C1-10 alkyl group, provided that at least a portion of the hydrogen atoms in the hydrocarbon group, acyl group, and alkoxy group may be substituted by a halogen atom, hydroxy group, carboxy group, nitro group, cyano group, or —NR.sup.3R.sup.4, and a hydrocarbon group present in the hydrocarbon group, in the acyl group, or in the alkoxy group may be interrupted by an ether bond, thioether bond, ester bond, thioester bond, amide bond, or urethane bond. R.sup.2 represents a C1-5 alkyl group. The symbol * in the formula indicates bonding with a neighboring group via the * moiety.) The photosensitive resin composition according to the present invention is also a photosensitive resin composition comprising (a) an alkali-soluble polyimide, (b) an unsaturated bond-containing compound, (c) a thermally crosslinkable compound, and (d) at least two species of oxime ester-type photopolymerization initiators. The photosensitive resin composition according to the present invention enables a high-sensitivity, high-quality photographic patterning of the cap portion of a hollow structure. A photosensitive resin sheet that uses the photosensitive resin composition according to the present invention is useful for application to the cap of the hollow structure of an electronic component that includes a hollow structure.

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 piezoelectric vibrating device according to the present invention is provided with: a piezoelectric vibration plate having first and second driving electrodes respectively formed on main surfaces on both sides thereof, the piezoelectric vibration plate further having first and second mounting terminals that are respectively connected to the first and second driving electrodes. The piezoelectric vibrating device is also provided with first and second sealing members respectively joined to the main surfaces on both sides of the piezoelectric vibration plate in a manner that the first and second driving electrodes of the piezoelectric vibration plate are covered with these sealing members. At least one of the first and second sealing members includes a film made of a resin.

An acoustic wave device includes a piezoelectric layer, electrodes, a support substrate, a resin sheet, a metallic frame, and an inorganic sheet. The electrodes oppose each other in an intersecting direction that intersects a thickness direction of the piezoelectric layer. The support substrate includes a first cavity extending through the support substrate so as to overlap at least a portion of the electrodes as viewed in the thickness direction. The resin sheet is arranged on a surface of the support substrate opposite to the piezoelectric layer to close the first cavity. The metallic frame includes a second cavity therein and surrounds the piezoelectric layer and the electrodes. The inorganic sheet is arranged on a surface of the metallic frame opposite to the piezoelectric layer to close the second cavity.

Acoustic resonator devices and filters are disclosed. An acoustic resonator chip includes a piezoelectric plate attached to a substrate, a portion of the piezoelectric plate forming a diaphragm spanning a cavity in the substrate. A first conductor pattern formed on a surface of the piezoelectric plate includes interleaved fingers of an interdigital transducer on the diaphragm and a first plurality of contact pads. A second conductor pattern is formed on a surface of an interposer, the second conductor pattern including a second plurality of contact pads. Each pad of the first plurality of contact pads is directly connected to a respective pad of the second plurality of contact pads. A seal is formed between a perimeter of the piezoelectric plate and a perimeter of the interposer.

An acoustic wave device includes a substrate, as well as a first electrode layer, a piezoelectric layer and a second electrode layer which are sequentially arranged on the substrate. The device further includes a protective layer. The protective layer is at least arranged at a first position above the surface, far away from the substrate, of the second electrode layer. The first position is a position, corresponding to a first overlapping region, above the second electrode layer. The first overlapping region, where an active area of the acoustic wave device is located, is at least a part of a region where the first electrode layer, the second electrode layer and the piezoelectric layer are overlapped. A fabrication method for an acoustic wave device is also provided.