An elastic wave device using the S0 mode of plate waves includes a support substrate, an acoustic reflective layer laminated on the support substrate, a piezoelectric body laminated on the acoustic reflective layer, and an IDT electrode disposed on the piezoelectric body. In the acoustic reflective layer, T1+T2 is between about 0.40 and about 0.60 inclusive in a portion in which low and high acoustic impedance layers are adjacent in the laminating direction. T1 is the thickness of the low acoustic impedance layers. T2 is the thickness of the high acoustic impedance layers. T1/(T1+T2) is between about 0.35 and about 0.65 inclusive.

A packaging method and package structure for a filter chip. The packaging method includes providing a circuit substrate, covering a first surface of the circuit substrate and/or filter chip with adhesive material and forming recessed cavities or closed cavities in the adhesive material. The method further includes adhering the filter chip to the first surface of circuit substrate via the adhesive material, such that surface acoustic wave transmitting regions of the filter chip correspond to the recessed cavities or closed cavities in the adhesive material to form a gap therebetween, and encapsulating the filter chip with encapsulating material. The method further includes forming interconnecting holes extending from a second surface of the circuit substrate to pins of the filter chip, filling the interconnecting holes with conductive material, so that the conductive material is in electrical contact with a chip pin bump or pad metal of the filter chip, and forming external pin pads on the second surface.

Aspects of this disclosure relate to acoustic wave devices on stacked die. A first die can include first acoustic wave device configured to generate a boundary acoustic wave. A second die can include a second acoustic wave device configured to generate a second boundary acoustic wave, in which the second die is stacked with the first die. The first acoustic wave resonator can include a piezoelectric layer, an interdigital transducer electrode on the piezoelectric layer, and high acoustic velocity layers on opposing sides of the piezoelectric layer. The high acoustic velocity layers can each have an acoustic velocity that is greater than a velocity of the boundary acoustic wave.

A multiplexer includes: first and second substrates overlapping with each other with an air gap interposed therebetween; a first filter disposed on the first substrate and including first series resonators connected in series with a first path, and first parallel resonators; and a second filter disposed on the second substrate and including second series resonators connected in series with a second path, and second parallel resonators connected between the second path and a ground, each of the second series resonators and the second parallel resonators including a piezoelectric film, a first electrode interposed between the piezoelectric film and the second substrate, a second electrode interposed between the piezoelectric film and the air gap, and a resonance region, in at least one second parallel resonator, the first electrode being coupled to the second path, the second electrode being coupled to the ground, the resonance region overlapping with the first path.

Manufacturing methods for a composite substrate for surface acoustic wave devices with improved characteristics is provided. The composite substrate for a surface acoustic wave device is configured to include a piezoelectric single crystal substrate and a supporting substrate. An intervening layer is provided between the piezoelectric single crystal substrate and the supporting substrate, the amount of chemisorbed water in the intervening layer is 1×10.sup.20 molecules/cm.sup.3 or less. At the bonding interface between the piezoelectric single crystal substrate and the supporting substrate, at least one of the piezoelectric single crystal substrate and the supporting substrate may have an uneven structure. It is preferable that the ratio of the average length RSm of the element in the sectional curve of the uneven structure and the wavelength λ of the surface acoustic wave when used as a surface acoustic wave device is 0.2 or more and 7.0 or less.

A method of manufacturing a packaged acoustic wave component includes forming a support substrate, forming a multi-layer piezoelectric substrate over a first side of the support substrate, and forming one or more metal layers over a second side of the support substrate that is opposite the first side of the support substrate. The method also includes forming one or more surface acoustic wave resonators or filters (including a multi-mode surface acoustic wave resonator or filter) over the multi-layer piezoelectric substrate. The method also includes forming one or more vias through the support substrate, and electrically connecting the multi-mode surface acoustic wave resonator or filter and the metal layers with the vias to provide a ground connection for the multi-mode surface acoustic wave resonator or filter.

An acoustic wave device includes a piezoelectric substrate, first and second signal electrodes, and a first ground electrode on a first main surface of the piezoelectric substrate, at least one insulation layer on a second main surface of the piezoelectric substrate, first and second signal terminals provided indirectly on the second main surface with the insulation layer interposed therebetween, and a ground terminal on the second main surface. An acoustic wave filter is provided on the piezoelectric substrate. The first signal electrode and the first signal terminal are electrically coupled, the second signal electrode and the second signal terminal are electrically coupled, and the first ground electrode and the ground terminal are electrically coupled. The ground terminal includes a contact portion in contact with the second main surface of the piezoelectric substrate.

A substrate that includes an encapsulation layer, a first acoustic resonator, a second acoustic resonator, at least one first dielectric layer, a plurality of first interconnects, at least one second dielectric layer, and a plurality of second interconnects. The first acoustic resonator is located in the encapsulation layer. The first acoustic resonator includes a first piezoelectric substrate comprising a first thickness. The second acoustic is located in the encapsulation layer. The second acoustic resonator includes a second piezoelectric substrate comprising a second thickness that is different than the first thickness. The at least one first dielectric layer is coupled to a first surface of the encapsulation layer. The plurality of first interconnects is coupled to the first surface of the encapsulation layer. The plurality of first interconnects is located at least in the at least one first dielectric layer.

An elastic wave device includes a piezoelectric layer including a first main surface and a second main surface facing the first main surface, an acoustically reflective layer stacked on the first main surface of the piezoelectric layer, an excitation electrode disposed on the piezoelectric layer, and a support layer. The acoustically reflective layer overlaps at least the excitation electrode in a plan view of the piezoelectric layer from the side of the second main surface. The support layer surrounds the acoustically reflective layer in a plan view of the piezoelectric layer from the side of the second main surface.

A method of printing comprises providing a component source wafer comprising components, a transfer device, and a patterned substrate. The patterned substrate comprises substrate posts that extend from a surface of the patterned substrate. Components are picked up from the component source wafer by adhering the components to the transfer device. One or more of the picked-up components are printed to the patterned substrate by disposing each of the one or more picked-up components onto one of the substrate posts, thereby providing one or more printed components in a printed structure.