There are provided a method for manufacturing a substrate excellent in heat dissipation with a small loss in radio frequencies with no need of a high temperature process in which a metal impurity is diffused, and a substrate of high thermal conductivity. A composite substrate according to the present invention is a composite substrate having a piezoelectric single crystal substrate, a support substrate, and an intermediate layer provided between the piezoelectric single crystal substrate and the support substrate. The intermediate layer is a film formed of an inorganic material, and at least a part of the film is thermally synthesized silica. The intermediate layer may be separated into at least two layers along the bonding surface of the composite substrate. The first intermediate layer in contact with the support substrate may be a layer including thermally synthesized silica.

An electronic component includes a package substrate extending in a longitudinal direction, and chip components disposed along the longitudinal direction of the package substrate and each connected to the package substrate by a bump. A height of a bump connecting at least one chip component disposed at an end portion in the longitudinal direction among the chip components and the package substrate is greater than a height of a bump connecting at least one chip component disposed inward relative to the end portion in the longitudinal direction among the chip components and the package substrate.

A surface acoustic wave (SAW) filter includes a bottom substrate, a piezoelectric layer disposed above the bottom substrate, the piezoelectric layer having a bottom surface facing the bottom substrate and a top surface opposite to the bottom surface, a lower cavity disposed below the piezoelectric layer, an interdigital transducer (IDT) disposed on the top surface of the piezoelectric layer, and a back electrode disposed on the bottom surface of the piezoelectric layer, and exposed in the lower cavity.

A method of manufacturing a composite substrate that includes bonding a silicon (Si) wafer having an interstitial oxygen concentration of 2 to 10 ppma to a piezoelectric material substrate as a support substrate, and thinning the piezoelectric material substrate after the bonding. The piezoelectric material substrate is particularly preferably a lithium tantalate wafer (LT) substrate or a lithium niobate (LN) substrate.

An electronics package has a multi-layer piezoelectric substrate with a piezoelectric layer over a substrate. The outer boundary of the piezoelectric layer is covered with a polyimide layer so that the polyimide layer is interposed between the piezoelectric layer and a metal portion (e.g., of copper (Cu)) to inhibit (e.g., prevent) stresses from the metal layer damaging the piezoelectric layer..

A surface acoustic wave package has a piezoelectric layer over a substrate and a thermally conductive structure attached to the substrate. The outer boundary of the piezoelectric layer is removed (e.g., etched) so that a resulting outer edge of the piezoelectric layer is spaced inward of an inner edge of the thermally conductive structure. The piezoelectric layer does not contact the thermally conductive structure to inhibit damage to the piezoelectric layer due to a stress differential between the substrate and the thermally conductive structure during a packaging process.

A method of making an acoustic wave device includes forming or providing a substrate, forming or providing a functional layer over at least a portion of the substrate, forming or providing a piezoelectric layer over at least a portion of the functional layer, and forming or providing an interdigital transducer electrode over the piezoelectric layer. Forming or providing the piezoelectric layer includes removing a portion of the piezoelectric layer so that the piezoelectric layer has an outer edge spaced inward of an outer edge of the substrate, and so that the outer edge of the piezoelectric layer is tapered at an angle relative to a surface of the substrate to thereby reduce an acoustic reflection magnitude at said outer edge of the piezoelectric layer.

An acoustic wave device includes a piezoelectric substrate, an IDT electrode and an electrode pad provided on a front surface of the piezoelectric substrate, a support layer provided on the front surface so as to surround the IDT electrode, a first cover layer and a second cover layer provided on the support layer such that the first cover layer, the second cover layer, the support layer, and the piezoelectric substrate seal the IDT electrode in a hollow space, a UBM portion joined to the electrode pad, and a bump joined to the UBM portion. A joint surface of the UBM portion at which the UBM portion is joined to the bump has a spherical shape or substantially spherical shape that is convex towards the bump side.

An elastic wave device includes first and second IDT electrodes provided over a principal surface of a piezoelectric substrate. The first IDT electrode is provided directly on a principal surface of the piezoelectric substrate and the second IDT electrode is provided over the principal surface with a first dielectric layer interposed therebetween. A second dielectric layer extends to upper portions of the first and second IDT electrodes. A wiring electrode passes over the second dielectric layer and extends to the upper portions of the first and second IDT electrodes. Respective angles between first and second side surfaces of the second dielectric layer and the principal surface of the piezoelectric substrate are smaller than an angle between a side surface of the first dielectric layer and the principal surface of the piezoelectric substrate.

An electro acoustic filter component with improved acoustic and/or electro acoustic performance is provided. The component comprises a piezoelectric material (PM) the sides of which are plane and preferably free from chipping defects. The piezoelectric material may be arranged above a carrier substrate (CS). A functional layer (FL) with plane sides may be arranged above an electrode structure (ES) as trimming, TCF or passivation layer. In the manufacturing method the piezoelectric material and the functional layer are removed from the dicing line, such that no chipping occurs for these layers.