Methods of forming a thin-film piezoelectric acoustic filter, a GaN-channel/buffer Bragg reflector, and a monolithically integrated GaN HEMT PA and CMOS over a [111] crystal orientation Si handle of a SOI wafer and resulting devices are provided. Embodiments include providing a SOI wafer including a [111] crystal orientation Si handle, a BOX layer, and a top Si layer; forming a CMOS device over the top Si layer; and forming a Bragg reflector over the [111] crystal orientation Si handle wafer, the Bragg reflector including a GaN stack with alternating layers of high/low acoustic impedance.

Methods of forming a thin-film piezoelectric acoustic filter, a GaN-channel/buffer Bragg reflector, and a monolithically integrated GaN HEMT PA and CMOS over a [111] crystal orientation Si handle of a SOI wafer and resulting devices are provided. Embodiments include providing a SOI wafer including a [111] crystal orientation Si handle, a BOX layer, and a top Si layer; forming a CMOS device over the top Si layer; and forming a Bragg reflector over the [111] crystal orientation Si handle wafer, the Bragg reflector including a GaN stack with alternating layers of high/low acoustic impedance.

An elastic wave device manufacturing method includes a preparing a piezoelectric wafer on which IDT electrodes are provided in elastic wave device forming portions, providing on a first main surface of the piezoelectric wafer support layers in the elastic wave device forming portions, bonding a cover member to cover the support layers to obtain a multilayer body, cutting the multilayer body in a first direction multiple times, cutting the multilayer body in a second direction orthogonal to the first direction to obtain elastic wave devices, in which a resin layer extends across a boundary between the elastic wave device forming portions adjacent to each other on the first main surface of the piezoelectric wafer, and the second cutting step is performed in a state in which the resin layer is present.

An acoustic wave device includes a piezoelectric substrate, an IDT electrode provided on the piezoelectric substrate, a support provided on the piezoelectric substrate so as to surround the IDT electrode, and a cover provided on the support. The support has a larger thermal expansion coefficient than the piezoelectric substrate. The IDT electrode is provided in a hollow space that is surrounded by the piezoelectric substrate, the support, and the cover. The support includes an inner surface on a side of the hollow space, and an outer surface on a side opposite to the inner surface, and the support includes a recess provided in at least one of the inner and outer surfaces.

An acoustic wave device includes an element substrate having piezoelectricity, an interdigital transducer electrode provided on the element substrate, and a mold resin covering the element substrate. When viewed in a cross section, the element substrate includes an interdigital transducer formation region in which the interdigital transducer electrode is provided and a pair of interdigital transducer non-formation regions in which the interdigital transducer electrode is not provided and located on both sides of the interdigital transducer formation region, and a thickness dimension of a center portion, in a width direction, of the interdigital transducer formation region is less than at least one of thickness dimensions of center portions, in the width direction, of the interdigital transducer non-formation regions.

An elastic wave device includes a spacer layer on or above a support substrate and outside a piezoelectric film as seen in a plan view from a thickness direction of the support substrate. A cover layer is disposed on the spacer layer. A through electrode extends through the spacer layer and the cover layer and is electrically connected to the wiring electrode. The wiring electrode includes a first section overlapping the through electrode as seen in the plan view from the thickness direction, a second section overlapping the piezoelectric film as seen in the plan view from the thickness direction, and a step portion defining a step in the thickness direction between the first section and the second section. The spacer layer includes an end portion embedded in the cover layer.

A package that includes a first filter device and a second filter device coupled to the first filter device. The first filter device includes a first substrate comprising a first piezoelectric material, and a first metal layer coupled to a first surface of the first substrate. The second filter device includes a second substrate comprising a second piezoelectric material, and a second metal layer coupled to a first surface of the first substrate. The package includes a first pillar interconnect configured to be electrically coupled to the first metal layer of the first filter device, where the first pillar interconnect extends through the second filter device. The package further includes a second pillar interconnect configured to be electrically coupled to the second metal layer of the second filter device.

A method of manufacturing an electronic device includes preparing an electronic component including a first substrate on a main surface of which a functional unit and a first resin layer are formed. The first resin layer has a first surface facing the main surface of the first substrate, a second surface opposed to the first surface, a cavity on the first surface enclosing the functional unit, and a portion defining a wall of the cavity. The first resin layer defines a recess provided with a solder layer on the second surface. The method further includes preparing a second substrate having an electrode pad formed on a main surface, aligning the electronic component with the second substrate to layer the solder layer and the electrode pad in contact with the solder layer, and forming the electronic component and the second substrate into the electronic device.

An assembly including an electrical connection substrate formed of material having a Young's modulus of less than about 10 MPa, an acoustic device die having opposite end portions mounted on and electrically connected to the electrical connection substrate and a mold compound layer encapsulating the acoustic device die and interfacing with the substrate.

In one aspect of the disclosure, a semiconductor package is disclosed. The semiconductor package includes a lead frame. A semiconductor die is attached to a first side of the lead frame. A protective shell covers at least a first portion of the first surface of the semiconductor die. The protective shell comprises of ink residue. A layer of molding compound covers an outer surface of the protective shell and exposed portion of the first surface of the semiconductor die. A cavity space is within an inner space of the protective shell and the first portion of the top surface of the semiconductor die.