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.

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 elastic wave device includes a supporting substrate, an acoustic multilayer film on the supporting substrate, a piezoelectric substrate on the acoustic multilayer film, and an IDT electrode on the piezoelectric substrate. An absolute value of a thermal expansion coefficient of the piezoelectric substrate is larger than an absolute value of a thermal expansion coefficient of the supporting substrate. The acoustic multilayer film includes at least four acoustic impedance layers. The elastic wave device further includes a bonding layer provided at any position in a range of from inside the first acoustic impedance layer from the piezoelectric substrate side towards the supporting substrate side, to an interface between the third acoustic impedance layer and the fourth acoustic impedance layer.

An elastic wave device includes a plate-shaped elastic wave element and a resin structure including a high elastic modulus resin portion and low elastic modulus resin portions. The low elastic modulus resin portions are provided in regions of side surfaces of an elastic wave element substrate, which extend from end portions at an IDT electrode formation surface side and do not reach a surface at a side opposite to an IDT electrode formation surface, and a remaining resin portion of a portion of the resin structure, which contacts with the side surfaces of the elastic wave element substrate, is the high elastic modulus resin portion.

An acoustic wave device includes: a piezoelectric substrate; and a pair of comb-shaped electrodes located on the piezoelectric substrate, each of the comb-shaped electrodes including a plurality of electrode fingers, side surfaces facing each other of the electrode fingers having a plurality of protrusion portions and a plurality of recessed portions arranged in an extension direction of the electrode fingers, ends of the protrusion portions and the recessed portions narrowing.

An acoustic wave device includes a support substrate having a central region and a surrounding region located around the central region, a silicon oxide film that is located in the central region directly or indirectly and that has a side surface, a piezoelectric layer that is provided on the silicon oxide film and that has a first principal surface and a second principal surface, an excitation electrode provided on at least one of the first principal surface and the second principal surface, a cover film provided to cover the entire side surface of the silicon oxide film, a resin layer that is provided in the surrounding region and that is provided to cover the side surface of the silicon oxide film from above the cover film, and a wiring electrode that is electrically connected to the excitation electrode and that extends from the piezoelectric layer to the resin layer.

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.

Disclosed is a packaged acoustic wave component and a method for making a packaged acoustic wave component. The packaged acoustic wave component comprises a substrate, a dielectric layer disposed over the substrate, a piezoelectric structure disposed over the dielectric layer, an electrode structure disposed over the piezoelectric structure, a polymer structure including a polymer structure wall portion and a polymer structure roof portion configured to form a cavity over the electrode structure, a metal structure disposed over the polymer structure, and a buffer coating disposed over the metal structure. The polymer structure includes a polymer structure lateral portion sandwiched between the substrate, the dielectric layer, or the piezoelectric structure on one side, and both the metal structure and the buffer coating on the other side.

A ceramic substrate is formed of polycrystalline ceramic and has a supporting main surface. At the supporting main surface of the ceramic substrate, the mean of grain sizes of the polycrystalline ceramic is 0.5 μm or more and less than 15 μm and the standard deviation of the grain sizes is less than 1.5 times the mean.

An electronic device includes a support substrate, a piezoelectric layer that is provided on the support substrate, a functional element including an electrode provided on a surface of the piezoelectric layer, a metallic frame body that is provided on the support substrate so as to surround the piezoelectric layer and the functional element in a plan view, a metallic lid that is provided on the frame body so as to form a space between the lid and the support substrate, and seals the functional element into the space, and a columnar body that is provided between the support substrate and the lid in the space.