An elastic wave device includes a substrate, an IDT electrode, a spacer layer, a cover, and a protective layer. The spacer layer is provided on the substrate and surrounds the IDT electrode. The cover is provided on the spacer layer, is spaced apart from the IDT electrode, and includes a first main surface adjacent to the spacer layer and a second main surface facing the first main surface. The protective layer includes a third main surface contacting the second main surface, a fourth main surface facing the third main surface, and a side surface connected to the fourth main surface. In at least portion of the side surface of the protective layer, a portion including an intersection line between the side surface and the fourth main surface is located farther inward than an outer edge of the substrate in plan view in the thickness direction of the substrate.

A production method for a surface acoustic wave device comprises the following steps: a step of providing a piezoelectric substrate comprising a transducer arranged on the main front face; a step of depositing a dielectric encapsulation layer on the main front face of the piezoelectric substrate and on the transducer; and a step of assembling the dielectric encapsulation layer with the main front face of a support substrate having a coefficient of thermal expansion less than that of the piezoelectric substrate. In additional embodiments, a surface acoustic wave device comprises a layer of piezoelectric material equipped with a transducer on a main front face, arranged on a substrate support of which the coefficient of thermal expansion is less than that of the piezoelectric material. The transducer is arranged in a dielectric encapsulation layer, between the layer of piezoelectric material and the support substrate.

This hermetic sealing lid member (1) is made of a clad material (10) including a base material layer (11) made of an Fe alloy that contains 4 mass % or more of Cr and a silver brazing layer (13) bonded onto a surface of the base material layer on a side closer to an electronic component housing member through an intermediate layer (12).

In an elastic wave device, an IDT electrode is disposed on a piezoelectric substrate and includes a close contact layer, which includes first and second main surfaces and side surfaces. The first main surface is in contact with the piezoelectric substrate, and at least two electrode layers are disposed on the close contact layer. The at least two electrode layers include a first electrode layer and a second electrode layer. The first electrode layer is made of a material that has a higher density than that of Al. The second electrode layer has a lower density than the first electrode layer. One of the at least two electrode layers has higher weather resistance than the close contact layer and covers the side surfaces of the close contact layer.

An acoustic wave device includes: a first substrate including a support substrate and a piezoelectric substrate bonded on an upper surface of the support substrate, and including a first acoustic wave element located on an upper surface of the piezoelectric substrate; a ring-shaped metal layer located in a region that surrounds the first acoustic wave element and in which the piezoelectric substrate is removed, a second substrate flip-chip mounted on an upper surface of the first substrate and including a functional element located on a lower surface of the second substrate; and a metallic member located on an upper surface of the ring-shaped metal layer, surrounding the second substrate in plan view, not located between the first substrate and the second substrate, and sealing the first acoustic wave element and the functional element so that the first acoustic wave element and the functional element are located across an air gap.

An acoustic wave device that utilizes a plate wave includes a recess in an upper surface of a support substrate. A piezoelectric substrate is located on the support substrate with a first principal surface side facing the support substrate. An IDT electrode is provided on the first principal surface of the piezoelectric substrate. The recess defines a cavity that is surrounded by the support substrate and the first principal surface of the piezoelectric substrate. The IDT electrode faces the cavity. The piezoelectric substrate includes through-holes that communicate the cavity and the second principal surface with each other. Sealing materials are filled respectively in the through-holes.

Methods are described for constructing a mechanical resonating structure by applying an active layer on a surface of a compensating structure. The compensating structure comprises one or more materials having an adaptive resistance to deform that reduces a variance in a resonating frequency of the mechanical resonating structure, wherein at least the active layer and the compensating structure form a mechanical resonating structure having a plurality of layers of materials A thickness of each of the plurality of layers of materials results in a plurality of thickness ratios therebetween.

A production method for a surface acoustic wave device comprises the following steps: a step of providing a piezoelectric substrate comprising a transducer arranged on the main front face; a step of depositing a dielectric encapsulation layer on the main front face of the piezoelectric substrate and on the transducer; and a step of assembling the dielectric encapsulation layer with the main front face of a support substrate having a coefficient of thermal expansion less than that of the piezoelectric substrate. In additional embodiments, a surface acoustic wave device comprises a layer of piezoelectric material equipped with a transducer on a main front face, arranged on a substrate support of which the coefficient of thermal expansion is less than that of the piezoelectric material. The transducer is arranged in a dielectric encapsulation layer, between the layer of piezoelectric material and the support substrate.

An electronic device includes an insulation material layer provided on a first main surface of a piezoelectric substrate and surrounding a functional element, and a protective layer provided on the insulation material layer. The piezoelectric substrate and the insulation material layer define a hollow portion accommodating the functional element. The protective layer includes a first portion above the hollow portion, a second portion adjacent to the first portion at one end of the second portion, and a third portion adjacent to the second portion at another end of the second portion. A distance between the first main surface and a surface of the protective layer in the thickness direction is greatest at a location where the second portion is adjacent to or in a vicinity of the first portion, and the distance is shortest at a location where the second portion is adjacent to or in a vicinity of the third portion.

An acoustic wave device includes a silicon support substrate, a silicon nitride film on the support substrate, a silicon oxide film on the silicon nitride film, a piezoelectric layer on the silicon oxide film and using Y-cut X-SAW propagation lithium tantalate, and an IDT electrode on the piezoelectric layer. A film thickness of the piezoelectric layer is equal to or less than about 1λ, Euler angles of the piezoelectric layer are (0±5°, θ, 0±5°) or (0±5°, θ, 180±5°), θ in the Euler angles of the piezoelectric layer is about 95.5°≤θ<117.5° or about −84.5°≤θ<−62.5°, and a relationship between θ in the Euler angles of the piezoelectric layer and a film thickness of the silicon nitride film is a combination shown in Table 1 or Table 2.