A manufacturing method of a composite substrate capable of suppressing damage due to heat treatment after bonding, and a composite substrate manufactured by the method are provided. The manufacturing method of a composite substrate according to the present invention is a manufacturing method of a composite substrate in which a piezoelectric wafer, which is a lithium tantalate wafer or lithium niobate wafer, and a support wafer are bonded together. This manufacturing method is characterized by a step of bonding a piezoelectric wafer and a support wafer, and a step of performing heat treatment of the wafer bonded in the step of bonding, with the non-bonded surface of the piezoelectric wafer being a mirror surface.

A composite substrate includes a support substrate made of Si, a high acoustic velocity material layer, a low acoustic velocity film, and a piezoelectric layer. In Euler angles (φ, θ, ψ) of the Si, φ and θ are within regions indicated by hatching with slant lines in FIG. 4. An acoustic wave device includes an IDT electrode in contact with the piezoelectric layer of the composite substrate.

A packaged acoustic wave component is disclosed. The packaged acoustic wave component can include a first acoustic wave resonator that includes a first interdigital transducer electrode that is positioned over a first piezoelectric layer. The packaged acoustic wave component can also include a second acoustic wave resonator including a second interdigital transducer electrode positioned over a second piezoelectric layer. The second piezoelectric layer is bonded to the first piezoelectric layer. The packaged acoustic wave component can further include a stopper structure that is positioned over the first piezoelectric layer. The first stopper structure is positioned above a via and extends through the first piezoelectric layer. The stopper structure is in electrical communication with the first interdigital transducer electrode and includes a material which reflects at least fifty percent of light having a wavelength of 355 nanometers.

An acoustic wave device includes an IDT electrode on a piezoelectric substrate and reflector electrodes on both sides of the IDT electrode in an acoustic wave propagation direction and each including electrode fingers with gaps therebetween, and first dielectric films between the reflector electrodes and the piezoelectric substrate in regions where the electrode fingers and the gaps of the reflector electrodes are provided.

An acoustic wave device includes a piezoelectric substrate and an IDT electrode on the piezoelectric substrate and including electrode fingers. A portion where adjacent electrode fingers of the IDT electrode overlap each other in an acoustic wave propagation direction is an intersecting region. The intersecting region includes a central region located in a central portion in a direction in which the electrode fingers extend and first and second edge regions on both sides of the central region in the direction in which the electrode fingers extend. The acoustic wave device further includes dielectric films between the piezoelectric substrate and the electrode fingers in the first and second edge regions. The dielectric films include at least one of hafnium oxide, niobium oxide, tungsten oxide, or cerium oxide.

An acoustic wave device includes an intermediate layer and a piezoelectric film that are laminated in that order on the support substrate. An interdigital transducer (IDT) electrode is provided on the piezoelectric film. Cavities are provided at least one of a location between the support substrate and the intermediate layer and a location in the intermediate layer.

An acoustic wave device includes a piezoelectric substrate and an IDT electrode. The IDT electrode includes a center area and first and second edge areas. Areas including the first and second edge areas and overlapping the areas in an acoustic-wave propagation direction include first and second expansion edge areas. First and second acoustic-velocity adjusters are provided in the first and second expansion edge areas. The first and second acoustic-velocity adjusters respectively includes first and second end portions and third and fourth end portions. The first to fourth end portions are located at outer sides of the first and second edge areas. End portions in at least one of two pairs including a pair of first and third end portions and a pair of second and fourth end portions do not overlap each other in a direction in which electrode fingers extend.

A filter module includes an inductor, a filter including first wiring, and second wiring between the inductor and the first wiring and being a direct-current floating potential. The inductor and the first wiring are magnetically coupled, the inductor and the second wiring are magnetically coupled, and the first wiring and the second wiring are capacitively coupled.

The present invention relates to a heterostructure, in particular, a piezoelectric structure, comprising a cover layer, in particular, a layer of piezoelectric material, the material of the cover layer having a first coefficient of thermal expansion, assembled to a support substrate, the support substrate having a second coefficient of thermal expansion substantially different from the first coefficient of thermal expansion, at an interface wherein the cover layer comprises at least a recess extending from the interface into the cover layer, and its method of fabrication.

A substrate for a surface acoustic wave device or bulk acoustic wave device, comprising a support substrate and an piezoelectric layer on the support substrate, wherein the support substrate comprises a semiconductor layer on a stiffening substrate having a coefficient of thermal expansion that is closer to the coefficient of thermal expansion of the material of the piezoelectric layer than that of silicon, the semiconductor layer being arranged between the piezoelectric layer and the stiffening substrate.