A bulk acoustic wave filter, a manufacturing method thereof, and a communication device are disclosed. The bulk acoustic wave filter includes a first filter substrate and a second filter substrate; the first filter substrate includes a first base substrate and a first resonator, a first electrode pad and a first auxiliary pad arranged on the first base substrate; the second filter substrate includes a second base substrate and a second resonator, a second electrode pad and a second auxiliary pad arranged on the second base substrate, the first filter substrate is arranged opposite to the second filter substrate, the first electrode pad and the second auxiliary pad are in contact with each other, and the second electrode pad and the first auxiliary pad are in contact with each other.

A MEMS component having increased integration density and a method for manufacturing such a component are specified. The component comprises a base wafer and a cover wafer arranged over this. A first cavity is arranged between the base wafer and the cover wafer. A second cavity is arranged over the cover wafer, below a thin-layer covering. The cavities contain component structures.

A quartz crystal resonator that includes a quartz crystal element having main surfaces extending in a plane φ degrees around a Z axis of the quartz crystal element and θ degrees around an X′ axis of the quartz crystal element; and an electrode in contact with the quartz crystal element, where x=t/T≥0.01, |φ−(−98.6x.sup.3+114.0x.sup.2−22.3x+1.3)|≤5 and |θ−(−9.5x.sup.3−10.9x.sup.2+1.4x+35.3)|≤0.5, wherein T is a thickness of the quartz crystal element and t is a thickness of the electrode.

An electronic component includes: a first substrate having a first surface; a second substrate having a second surface facing the first surface across an air gap; a first coil pattern that is located on the first surface so as to face the second surface across the air gap; a second coil pattern that is located in a second region on the second surface and faces the first surface across the air gap, at least a part of the second region overlapping with a first region in plan view, the first region being formed of a region in which the first coil pattern is located and a region surrounded by the first coil pattern; and a connection terminal connecting the first coil pattern and the second coil pattern.

A semiconductor device and a method of manufacturing a semiconductor device are provided. The semiconductor device includes a carrier, an element, and a first electronic component. The element is disposed on the carrier. The first electronic component is disposed above the element. The element is configured to adjust a first bandwidth of a first signal transmitted from the first electronic component.

A quartz crystal unit comprising a quartz crystal resonator having a base portion, and first and second tuning fork arms connected to the base portion, the base portion having a length less than 0.5 mm and greater than a spaced-apart distance between the first and second tuning fork arms, each of the first and second tuning fork arms having a width less than 0.1 mm and a length less than 1.56 mm, and a plurality of different widths including a first width and a second width greater than the first width, at least one groove being formed in at least one of opposite main surfaces of each of the first and second tuning fork arms so that a length of the at least one groove is within a range of 0.3 mm to 0.79 mm, the quartz crystal resonator being housed in a case, and a lid being connected to the case.

An electronic component includes a mounting substrate, and first and second devices each including a functional element. The first device is spaced apart from and faces the mounting substrate. The second device is located on the mounting substrate and faces the first device. A functional element of the first device is located on a first surface facing the second device, in the first device. A functional element of the second device is located on a second surface facing the first device, in the second device.

An oven-controlled crystal oscillator according to one or more embodiments includes a core section having at least an oscillation IC, a crystal resonator, and a heater IC. The core section is hermetically encapsulated in a heat-insulating package. The core section is supported by the package via a core substrate. The core substrate is connected to the package outside a region where the core section is provided in plan view.

A circuit device includes a first terminal, a first oscillation circuit oscillating a resonator and generating a first voltage for automatic gain control for controlling amplitude of a signal output from the resonator, a digital signal generation circuit generating a digital signal corresponding to the first voltage, and a first interface circuit outputting the digital signal to the first terminal.

An oscillator includes a package having a plurality of external terminals disposed on a mounting surface, a circuit element housed in the package, and a resonator which is housed in the package, and is electrically coupled to the circuit element, wherein the circuit element is electrically coupled to the package with a plurality of pads each of which is bonded to the package via a bump member, the circuit element overlaps at least one of the external terminals in a plan view, and each of the bump members is bonded to the package at a position where at least a part of the bump member does not overlap the plurality of external terminals in the plan view.