A lithium tantalate single crystal substrate for a surface acoustic wave device that is a rotated Y-cut LiTaO3 substrate whose crystal orientation has a Y-cut angle of not smaller than 36° and not larger than 49° and which has such a Li concentration profile after diffusion of Li into the substrate from the surface thereof that the Li concentration at the surface of the substrate differs from that inside the substrate. A shear vertical type elastic wave whose main components are vibrations in the thickness direction and in the propagation direction and which is among those elastic waves which propagate in the X axis direction within the surface of this LiTaO3 substrate has an acoustic velocity of not lower than 3140 m/s and not higher than 3200 m/s.

A lithium tantalate single crystal substrate for a surface acoustic wave device that is a rotated Y-cut LiTaO3 substrate whose crystal orientation has a Y-cut angle of not smaller than 36° and not larger than 49° and which has such a Li concentration profile after diffusion of Li into the substrate from the surface thereof that the Li concentration at the surface of the substrate differs from that inside the substrate. A shear vertical type elastic wave whose main components are vibrations in the thickness direction and in the propagation direction and which is among those elastic waves which propagate in the X axis direction within the surface of this LiTaO3 substrate has an acoustic velocity of not lower than 3140 m/s and not higher than 3200 m/s.

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.

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.

A manufacturing method of a mounting structure includes: a step of preparing a mounting member including a first circuit member and a plurality of second circuit members placed on the first circuit member; a disposing step of disposing a thermosetting sheet and a thermoplastic sheet on the mounting member, with the thermosetting sheet interposed between the thermoplastic sheet and the first circuit member; a first sealing step of pressing a stack of the thermosetting sheet and the thermoplastic sheet against the first circuit member, and heating the stack, to seal the second circuit members and to cure the thermosetting sheet into a cured layer; and a removal step of removing the thermoplastic sheet from the cured layer. At least one of the second circuit members is a hollow member having a space from the first circuit member, and in the first sealing step, the second circuit members are sealed so as to maintain the space.

A manufacturing method of a mounting structure includes: a step of preparing a mounting member including a first circuit member and a plurality of second circuit members placed on the first circuit member; a disposing step of disposing a thermosetting sheet and a thermoplastic sheet on the mounting member, with the thermosetting sheet interposed between the thermoplastic sheet and the first circuit member; a first sealing step of pressing a stack of the thermosetting sheet and the thermoplastic sheet against the first circuit member, and heating the stack, to seal the second circuit members and to cure the thermosetting sheet into a cured layer; and a removal step of removing the thermoplastic sheet from the cured layer. At least one of the second circuit members is a hollow member having a space from the first circuit member, and in the first sealing step, the second circuit members are sealed so as to maintain the space.

In an elastic wave filter apparatus, IDT electrodes and first and second electrode lands are provided on a first main surface of a piezoelectric substrate. The piezoelectric substrate, a supporting layer, and a covering member define a hollow portion. A signal terminal, a ground terminal, and a heat diffusion layer are provided on a second main surface of the piezoelectric substrate. The first and second electrode lands are electrically connected by first and second connection electrodes to the signal terminal and the ground terminal, respectively. The heat diffusion layer is provided at a position where the heat diffusion layer overlaps at least a portion of the IDT electrodes across the piezoelectric substrate.

In an elastic wave filter apparatus, IDT electrodes and first and second electrode lands are provided on a first main surface of a piezoelectric substrate. The piezoelectric substrate, a supporting layer, and a covering member define a hollow portion. A signal terminal, a ground terminal, and a heat diffusion layer are provided on a second main surface of the piezoelectric substrate. The first and second electrode lands are electrically connected by first and second connection electrodes to the signal terminal and the ground terminal, respectively. The heat diffusion layer is provided at a position where the heat diffusion layer overlaps at least a portion of the IDT electrodes across the piezoelectric substrate.

Disclosed is a device that includes a crystalline substrate and a patterned aluminum-based material layer disposed onto the crystalline substrate. The patterned aluminum-based material layer has a titanium-alloyed surface. A titanium-based material layer is disposed over select portions of the titanium-alloyed surface. In an exemplary embodiment, the patterned aluminum-based material layer forms a pair of interdigitated transducers to provide a surface wave acoustic (SAW) device. The SAW device of the present disclosure is usable to realize SAW-based filters for wireless communication equipment.

Disclosed is a device that includes a crystalline substrate and a patterned aluminum-based material layer disposed onto the crystalline substrate. The patterned aluminum-based material layer has a titanium-alloyed surface. A titanium-based material layer is disposed over select portions of the titanium-alloyed surface. In an exemplary embodiment, the patterned aluminum-based material layer forms a pair of interdigitated transducers to provide a surface wave acoustic (SAW) device. The SAW device of the present disclosure is usable to realize SAW-based filters for wireless communication equipment.