A method for forming cavity of bulk acoustic wave resonator comprising following steps of: forming a sacrificial epitaxial structure mesa on a compound semiconductor substrate; forming an insulating layer on the sacrificial epitaxial structure mesa and the compound semiconductor substrate; polishing the insulating layer by a chemical-mechanical planarization process to form a polished surface; forming a bulk acoustic wave resonance structure on the polished surface, which comprises following steps of: forming a bottom electrode layer on the polished surface; forming a piezoelectric layer on the bottom electrode layer; and forming a top electrode layer on the piezoelectric layer, wherein the bulk acoustic wave resonance structure is located above the sacrificial epitaxial structure mesa; and etching the sacrificial epitaxial structure mesa to form a cavity, wherein the cavity is located under the bulk acoustic wave resonance structure.

A method for forming cavity of bulk acoustic wave resonator comprising following steps of: forming a sacrificial epitaxial structure mesa on a compound semiconductor substrate; forming an insulating layer on the sacrificial epitaxial structure mesa and the compound semiconductor substrate; polishing the insulating layer by a chemical-mechanical planarization process to form a polished surface; forming a bulk acoustic wave resonance structure on the polished surface, which comprises following steps of: forming a bottom electrode layer on the polished surface; forming a piezoelectric layer on the bottom electrode layer; and forming a top electrode layer on the piezoelectric layer, wherein the bulk acoustic wave resonance structure is located above the sacrificial epitaxial structure mesa; and etching the sacrificial epitaxial structure mesa to form a cavity, wherein the cavity is located under the bulk acoustic wave resonance structure.

The disclosed technology generally relates to packaging a quartz crystal, and more particularly to bonding a quartz crystal using sintering silver paste. In one aspect, a method of packaging a quartz crystal comprises attaching a quartz crystal to a package substrate using one or more silver paste layers comprising silver particles. The method additionally comprises sintering the silver paste in a substantially oxygen-free atmosphere and at a sintering temperature sufficient to cause sintering of the silver particles. The sintering is such that the quartz crystal exhibits a positive drift in resonance frequency of the quartz crystal over time. The method further comprises hermetically sealing the quartz crystal in the package substrate.

The disclosed technology generally relates to packaging a quartz crystal, and more particularly to bonding a quartz crystal using sintering silver paste. In one aspect, a method of packaging a quartz crystal comprises attaching a quartz crystal to a package substrate using one or more silver paste layers comprising silver particles. The method additionally comprises sintering the silver paste in a substantially oxygen-free atmosphere and at a sintering temperature sufficient to cause sintering of the silver particles. The sintering is such that the quartz crystal exhibits a positive drift in resonance frequency of the quartz crystal over time. The method further comprises hermetically sealing the quartz crystal in the package substrate.

Techniques for improving Bulk Acoustic Wave (BAW) resonator structures are disclosed, including fluidic systems, oscillators and systems that may include such devices. A bulk acoustic wave (BAW) resonator may comprise a substrate and a first layer of piezoelectric material. The bulk acoustic wave (BAW) resonator may comprise a top electrode. A sensing region may be acoustically coupled with the top electrode of the bulk acoustic wave (BAW) resonator.

A vibration element includes: a quartz crystal substrate having a first vibration part and a second vibration part; a pair of first excitation electrodes formed at two main surfaces of the quartz crystal substrate, at the first vibration part; and a pair of second excitation electrodes formed in such a way as to sandwich the second vibration part in a direction of thickness of the quartz crystal substrate, at the second vibration part. At least one second excitation electrode of the pair of second excitation electrodes is formed at an inclined surface inclined to at least one of the two main surfaces.

The vibrator element includes a base part, a vibrating arm extending from the base part, and a weight provided to the vibrating arm, wherein the weight includes a thick film part, a thin film part thinner in film thickness than the thick film part, and a connection part which is located between the thick film part and the thin film part to connect the thick film part and the thin film part to each other, and which forms a taper shape gradually decreasing in film thickness in a direction from the thick film part side toward the thin film part.

The vibrator element includes a base part, a vibrating arm extending from the base part, and a weight provided to the vibrating arm, wherein the weight includes a thick film part, a thin film part thinner in film thickness than the thick film part, and a connection part which is located between the thick film part and the thin film part to connect the thick film part and the thin film part to each other, and which forms a taper shape gradually decreasing in film thickness in a direction from the thick film part side toward the thin film part.

A packaged acoustic wave component can include a dielectric layer disposed over a substrate, a piezoelectric structure disposed over the dielectric layer, and an electrode structure disposed over the piezoelectric structure. The component can further include a polymer structure including a polymer structure wall portion and a polymer structure roof portion configured to form a cavity over the electrode structure, a metal structure disposed over the polymer structure. A buffer coating can be disposed over the metal structure. The buffer coating can include a polymer material with a filler material.

A packaged acoustic wave component can include a dielectric layer disposed over a substrate, a piezoelectric structure disposed over the dielectric layer, and an electrode structure disposed over the piezoelectric structure. The component can further include a polymer structure including a polymer structure wall portion and a polymer structure roof portion configured to form a cavity over the electrode structure, a metal structure disposed over the polymer structure. A buffer coating can be disposed over the metal structure. The buffer coating can include a polymer material with a filler material.