An acoustic wave device includes: a first substrate having a first surface on which an acoustic wave element is located; a second substrate having a second surface on which a functional element is located; a third substrate having a third surface, which faces the first and second surfaces, and a fourth surface being opposite to the third surface, a first metal layer separated from the acoustic wave element and a wiring line in the first substrate and connecting the first and third surfaces; a second metal layer separated from the functional element and a wiring line in the second substrate and connecting the second and third surfaces; a first metal pattern located on the third surface, being in contact with the first and second metal layers, and connecting the first and second metal layers; and a terminal located on the fourth surface and electrically connectable to the first metal pattern.

A high-frequency module that performs filtering of signals transmitted and received through an antenna includes an antenna terminal, a transmission terminal, a reception terminal, a reception filter connected between the antenna terminal and the reception terminal, a transmission filter connected between the antenna terminal and the transmission terminal, a first element connected between the antenna terminal and the transmission filter, and a second element connected in series between the transmission terminal and the transmission filter. The first element and the second element are capacitively coupled to each other.

A multiplexer includes: first and second substrate respectively having first and second surfaces facing each other across an air gap; a first filter including first resonators located on the first surface and connected between a common terminal and a first terminal; a second filter including second resonators located on the second surface and connected between the common terminal and a second terminal, a first resonator connected in series between the common terminal and the first terminal and closest to the common terminal overlapping with a second resonator connected in series between the common terminal and the second terminal and closest to the common terminal, first resonators other than the first resonator closest to the common terminal not overlapping with the second resonators, second resonators other than the second resonator closest to the common terminal not overlapping with the first resonators.

A multiplexer includes: one or more transmit filters that are connected between an antenna terminal and one or more transmit terminals; one or more receive filters that are connected between the antenna terminal and one or more receive terminals; and a circuit that includes a longitudinally coupled acoustic wave filter and is connected in parallel to one or more series resonators of a first filter that is one of the one or more transmit filters and the one or more receive filters and includes the one or more series resonators and one or more parallel resonators each formed of a piezoelectric thin film resonator, wherein the longitudinally coupled acoustic wave filter is formed of IDTs formed on a chip of a second filter that is another one of the one or more transmit filters and the one or more receive filters and formed of a surface acoustic wave resonator.

According to some implementations, a radio-frequency (RF) module is disclosed, comprising a first substrate. The radio-frequency module also includes a radio-frequency device mounted on the first substrate, the radio-frequency device including a second substrate. In some embodiments, the second substrate includes a first side and a second side, a set of support structures implemented on the second side of the substrate, the set of support structures defining a mounting volume on the second side of the second substrate, and a component implemented within the mounting volume. The radio-frequency module may further comprise a first overmold structure encapsulating at least a portion of the set of support structures.

An integrated radio frequency (RF) circuit combines complementary features of passive devices and acoustic filters and includes a first die, a second die, and a third die. The first die includes a substrate having one or more passive devices. The second die includes a first acoustic filter. The second die is stacked and coupled to a first surface of the first die. The third die includes a second acoustic filter. The third die is stacked and coupled to a second surface opposite the first surface of the first die.

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.

A piezoelectric thin film resonator includes: a substrate; a piezoelectric film located on the substrate and including a penetration hole penetrating therethrough; a lower electrode and an upper electrode facing each other across at least a part of the piezoelectric film; and a protective film covering an upper surface of the piezoelectric film, a side surface of the piezoelectric film, and an inner surface of the penetration hole.

A technique capable of maintaining the filter characteristics of a transmitting filter and a receiving filter by reducing the influences of heat from the power amplifier given to the transmitting filter and the receiving filter as small as possible in the case where the transmitting filter and the receiving filter are formed on the same semiconductor substrate together with the power amplifier in a mobile communication equipment typified by a mobile phone is provided. A high heat conductivity film HCF is provided on a passivation film PAS over the entire area of a semiconductor substrate 1S including an area AR1 on which an LDMOSFET is formed and an area AR2 on which a thin-film piezoelectric bulk wave resonator BAW is formed. The heat mainly generated in the LDMOSFET is efficiently dissipated in all directions by the high heat conductivity film HCF formed on the surface of the semiconductor substrate 1S.

The present invention relates to a BAW filter operating with bulk acoustic waves, which has a multilayer construction, wherein functional layers of a BAW resonator operating with bulk acoustic waves are realized by the multilayer construction, and wherein an interconnection of passive components is furthermore formed by the multilayer construction, said interconnection forming a balun, wherein the balun has at least one inductance (L1, L2, L3) and at least one capacitance (C1, C2) which are formed from structured functional layers of the BAW resonator. Furthermore, the invention relates to a method for producing the BAW filter.