The invention discloses a bulk acoustic wave resonator and a manufacturing method thereof, the bulk acoustic wave resonator comprising: an air gap arranged at the external of the effective piezoelectric region, the air gap being formed between the upper electrode and the piezoelectric layer and/or between the piezoelectric layer and the substrate, and covering the end part, proximal to the air gap, of the lower electrode or connecting to the end part of the lower electrode, wherein the air gap is provided with a first end proximal to the effective piezoelectric region, and at least a portion of the upper surface, starting from the first end, of the air gap is an arch-shaped upper surface. The bulk acoustic wave resonator of the present invention capable of increasing a quality factor (Q) and an effective electromechanical coupling coefficient (K.sup.2.sub.t,eff) and improving the electrostatic discharge (ESD) immunity.

A bulk acoustic wave resonator includes: support members disposed between air cavities; a resonant part including a first electrode, a piezoelectric layer, and a second electrode sequentially disposed above the air cavities and on the support members; and a wiring electrode connected either one or both of the first electrode and the second electrode, and disposed above one of the air cavities, wherein a width of an upper surface of the support members is greater than a width of a lower surface of the support members, and side surfaces of the support members connecting the upper surface and the lower surface to each other are inclined.

An acoustic wave device includes a piezoelectric substrate that includes first and second main surfaces, an IDT electrode on the first main surface, a support having a rectangular or substantially rectangular frame shape and including a cavity, first and second sides, and a first corner portion connected to the first and second sides, and the support being provided on the first main surface such that the cavity surrounds the IDT electrode, and a cover on the support and covering the cavity. A straight or substantially straight grinding trace is provided on the second main surface. The grinding trace leads to the first corner portion as viewed in plan. One of an angle between the first side and the grinding trace and an angle between the second side and the grinding trace as viewed in plan is about 9.5 or less.

A quartz crystal resonator that includes a substrate including a vibration portion, a frame portion that surrounds the vibration portion, and first to fourth coupling portions that couple the vibration portion and the frame portion to each other; and first and second excitation electrodes. An intersecting point of diagonal lines of a quadrangle formed by first to fourth connection portions is located on the positive side of the z axis relative to the x axis.

An electronic component housing package includes: a base section having a mounting section for an electronic component; a projecting part that is positioned on the base section and projects from the base section; a frame part that is positioned on the base section and surrounds the mounting section; a frame-shaped metalized layer that is positioned on the frame part; a plurality of external connection conductors that is positioned opposite the mounting section in the thickness direction; a connection conductor which is positioned on the projecting part and for connecting to the electronic component; and a wiring conductor that is connected to the connection conductor and that is led out to the base section. The thickness of the connection conductor gradually increases toward the wiring conductor.

Acoustic filters, resonators and methods are disclosed. An acoustic filter device includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces, the back surface attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm that spans a cavity in the substrate. An interdigital transducer is formed on the front surface of the piezoelectric plate with interleaved fingers of the IDT disposed on the diaphragm. At least a portion of a perimeter of the cavity is curved.

A fine dust concentration sensor includes a bulk acoustic resonator and a cap including an upper portion with holes therein and a lateral portion connected to the upper portion to accommodate the bulk acoustic resonator. An upper surface of the upper portion of the cap is coated with a hydrophobic material.

A through hole formed in an AT-cut crystal plate includes an inclined surface (72) that extends from a peripheral area toward a penetrating part (71) in a center part of the through hole. The inclined surface (72) includes: a first crystal surface S1 that extends from the penetrating part (71) toward the peripheral area of the through hole in a Z and a +X directions; a second crystal surface S2 that extends from the penetrating part (71) toward the peripheral area of the through hole in the Z and the +X directions and that contacts with the first crystal surface S1 in the +Z and the +X directions of the first crystal surface S1; and a third crystal surface S3 that contacts with the second crystal surface S2 in the +X direction of the second crystal surface S2 and that contacts with the main surface of the AT-cut crystal plate. A compensation surface Sc is formed between the main surface of the AT-cut crystal plate and the three crystal surfaces Si to S3 to prevent first and second ridge lines L1 and L2 from reaching the main surface of the AT-cut crystal plate.

The piezoelectric vibration device disclosed herein includes: a piezoelectric vibrator including a plurality of terminals for external connection and a plurality of electrodes for mounting purpose; and an integrated circuit element mountable to the piezoelectric vibrator and including a plurality of mounting terminals connectable to the plurality of electrodes for mounting purpose. At least one of the electrodes for mounting purpose connected to the terminals for external connection has a wiring pattern extending more inward in a mounting region where the integrated circuit element is mounted than the mounting terminals of the integrated circuit element.

A method for manufacturing a Bulk Acoustic Wave (BAW) resonator module is provided. The method includes providing a substrate, defining a platform region on the surface of the substrate, disposing a BAW resonator device on the surface of the substrate within the platform region, and etching an isolation trench circumscribing at least 50% of a circumference of the platform region.