Heat dissipating characteristics of an acoustic wave filter is improved. A high frequency module includes a mounting substrate, an acoustic wave filter, a resin layer, and a shield layer. The mounting substrate has a first main surface and a second main surface that face each other. The acoustic wave filter is arranged near the first main surface of the mounting substrate. The resin layer is arranged on the first main surface of the mounting substrate and covers an outer peripheral surface of the acoustic wave filter. The shield layer covers the resin layer and the acoustic wave filter. The shield layer is in contact with a second main surface of the acoustic wave filter that is far from the mounting substrate.

An acoustic wave device includes a piezoelectric material substrate, an intermediate layer on the piezoelectric material substrate and composed of one or more materials selected from the group consisting of silicon oxide, aluminum nitride and sialon. A bonding layer is on the intermediate layer and is composed of one or more materials selected from the group consisting of tantalum pentoxide, niobium pentoxide, titanium oxide, mullite, alumina, and a high resistance silicon and hafnium oxide. A supporting body is composed of a polycrystalline ceramic and is bonded to the bonding layer by direct bonding, and an electrode is on the piezoelectric material substrate.

Embodiments of the present application provide a wafer level surface acoustic wave filter and a package method, the surface acoustic wave filter includes a wafer, an electrode layer, a supporting wall and a cover plate; wherein, the wafer includes a substrate layer and a piezoelectric thin film layer combined together by wafer bonding, the electrode layer is arranged on a surface of the piezoelectric thin film layer, the supporting wall surrounds between the piezoelectric thin film layer and the cover plate to form a sealed cavity; and the cover plate includes at least a first material layer, which uses the same material as the substrate layer.

A packaged acoustic wave component has two acoustic wave devices interconnected by a thermally conductive frame, at least one of the acoustic wave devices including a multi-layer piezoelectric substrate. The multi-layer piezoelectric substrate includes a support layer and a piezoelectric layer disposed over the support layer. An interdigital transducer (IDT) electrode is disposed over the piezoelectric layer. The support layer has a high thermal conductivity, allowing heat generated by a first acoustic wave device with the multi-layer piezoelectric substrate to be transferred to a second acoustic wave device on which it is stacked to dissipate heat from the first acoustic wave device by way of the thermally conductive frame spaced from ends of the piezoelectric layers.

Surface acoustic wave resonators are disclosed. In certain embodiments, a surface acoustic wave resonator can include a high impedance layer, a piezoelectric layer over the high impedance layer, an interdigital transducer electrode over the piezoelectric layer, and a low impedance layer between the high impedance layer and the piezoelectric layer. An acoustic impedance of the high impedance layer is greater than an acoustic impedance of the piezoelectric layer. An acoustic impedance of the low impedance layer is lower than the acoustic impedance of the high impedance layer. The piezoelectric layer can have a cut angle in a range from 115° to 135°. The surface acoustic wave resonator is configured to generate a Rayleigh mode surface acoustic wave having a wavelength of λ.

A method of making a surface acoustic wave package includes bonding a piezoelectric layer over a substrate and attaching a metal structure over the substrate, with the piezoelectric layer positioned between at least a portion of the substrate and at least a portion of the metal structure. The method also includes removing (e.g., etching) an outer boundary of the piezoelectric layer so that a resulting outer edge of the piezoelectric layer is spaced inward of an inner edge of the metal package (e.g., the piezoelectric layer does not contact the metal package). The method inhibit damage to the piezoelectric layer due to a stress differential between the substrate and the thermally conductive structure during a packaging process.

An acoustic wave element includes an IDT electrode including a plurality of electrode fingers and exciting a surface acoustic wave, a first substrate including an upper surface on which the IDT electrode is located, the first substrate being configured by a piezoelectric crystal, and a second substrate bonded to a side where a lower surface of the first substrate is located. Either of a first region which continues from the lower surface of the first substrate toward a side where the upper surface is located or a second region which continues from the lower surface of the first substrate toward a side where the second substrate is located is a low resistance region having a resistance value of 5×10.sup.3Ω to 5×10.sup.7Ω.

Acoustic wave resonators are disclosed that include a piezoelectric layer and an interdigital transducer electrode over the piezoelectric layer. The interdigital transducer electrode has a rotation angle and a tilt angle. The rotation angle and the tilt angle can together increase a figure of merit of the acoustic wave device. The rotation angle and the tilt angle can both be non-zero.

A front-end module may include an acoustic wave filter with a first and second interdigital transducer electrode, and a low noise amplifier (LNA) that converts a differential input to a single-ended output with respect to ground. The first interdigital transducer electrode may be single-ended with a first input bus bar configured to receive an input signal and a second input bus bar connected to ground. The second interdigital transducer electrode may be differential with a first output bus bar connected to a first output terminal and a second output bus bar connected to a second output terminal. The LNA may have a differential input connected to the acoustic wave filter, a first input transistor that receives a first signal from the first output terminal of the acoustic wave filter, and a second input transistor that receives a second signal from the second output terminal of the acoustic wave filter.

A stacked acoustic wave device assembly is disclosed. The stacked acoustic wave device assembly can include a first acoustic wave device including a first double acoustic mirror structure having a first solid acoustic mirror and a second solid acoustic mirror, and a first piezoelectric layer between the first and second solid acoustic mirrors. The stacked acoustic wave device assembly can include a second acoustic wave device including a second double acoustic mirror structure having a third solid acoustic mirror and a fourth acoustic mirror, and a second piezoelectric layer between the third and fourth acoustic mirrors. The second acoustic wave device is vertically stacked on the first acoustic wave device such that the second solid acoustic mirror and the fourth solid acoustic mirror are positioned between the first and second piezoelectric layers.