There are disclosed acoustic resonators and method of fabricating acoustic resonators. An acoustic resonator includes a single-crystal piezoelectric plate having front and back surfaces, the back surface attached to a surface of a substrate except for portions of the piezoelectric plate forming a diaphragm spanning a cavity in the substrate. A conductor pattern on the front surface includes an interdigital transducer (IDT) with interleaved fingers of the IDT disposed on the diaphragm. A periodic array of holes is provided in the diaphragm.

A method of manufacturing surface acoustic wave device chips includes grinding a reverse side of a wafer with a surface acoustic wave device formed in each area demarcated by a plurality of crossing projected dicing lines on a face side of the wafer; before or after grinding, applying a laser beam to the reverse side of the wafer such that the laser beam is focused at a position within the wafer, the position being closer to the face side of the wafer than a position corresponding to a reverse side of each of the surface acoustic wave device chips to be produced from the wafer, thereby forming a modified layer for diffusing an acoustic wave; and after grinding and applying the laser beam, dividing the wafer along the projected dicing lines into a plurality of the surface acoustic wave device chips.

There is provided a SAW filter manufacturing method for manufacturing a SAW filter from a piezoelectric substrate having planned dividing lines set on a top surface of the piezoelectric substrate, and having a device including comb-shaped electrodes in regions demarcated by the planned dividing lines. The method includes a structure forming step of forming a structure having projections and depressions on an undersurface side of the piezoelectric substrate by irradiating the piezoelectric substrate with a laser beam of a wavelength absorbable by the piezoelectric substrate from the undersurface side of the piezoelectric substrate, and a dividing step of dividing the piezoelectric substrate along the planned dividing lines after the structure forming step.

A hybrid structure for a surface acoustic wave device comprises a useful layer of piezoelectric material having a free first surface and a second surface disposed on a support substrate that has a lower coefficient of thermal expansion than that of the useful layer. The hybrid structure further comprises a trapping layer disposed between the useful layer and the support substrate, and at least one functional interface of predetermined roughness between the useful layer and the trapping layer.

In order to improve heat dissipation from electrical components with heat-generating component structures, it is proposed to provide a radiation layer with a large surface in the area of the component structures. Preferably, the radiation layer is very heat-conductive or in heat-conductive connection with the component structures.

An elastic wave device includes a piezoelectric substrate with first and second main surfaces internally facing each other, an elastic-wave element that includes an interdigital transducer electrode provided on or in the first main surface of the piezoelectric substrate, and a first protective film that is provided on the first main surface of the piezoelectric substrate so as to cover the IDT electrode. The IDT electrode includes a main electrode layer made of a metal having a density higher than that of the first protective film. The piezoelectric substrate has a thickness of about 0.35 mm or smaller, and irregularities are located on the second main surface.

It is formed, over a supporting body made of a ceramic, a bonding layer composed of one or more material selected from the group consisting of mullite, alumina, tantalum pentoxide, titanium oxide and niobium pentoxide. Neutralized beam is irradiated onto a surface of the bonding layer to activate the surface of the bonding layer. The surface of the bonding layer and the piezoelectric single crystal substrate are bonded by direct bonding.

The present invention provides a surface acoustic wave sensor capable of suitably controlling the flow of a liquid sample onto IDT electrodes. A surface acoustic wave sensor has a piezoelectric substrate, a first IDT electrode and a second IDT electrode which are located on the upper surface of the piezoelectric substrate and are separated from each other while sandwiching a detection part on the piezoelectric substrate therebetween, and the cover which forms the space being on the first IDT electrode, second IDT electrode, and the detection part and straddling them. On the lower surface of the cover, the detection part-facing surface facing the detection part has a smaller contact angle to the liquid sample than that of a pair of electrode-facing surfaces facing the first IDT electrode and second IDT electrode.

Methods for making laser-marked packaged surface acoustic wave devices are provided. The method may include directly marking a surface of a piezoelectric substrate, where the opposite surface of the piezoelectric substrate includes a package structure encapsulating a surface acoustic wave device. The method may include exposing the surface of the piezoelectric substrate to light from a deep ultraviolet laser. By using a wavelength readily absorbed by the piezoelectric substrate, a relatively shallow marking may be made in the piezoelectric substrate. The markings may extend less than 1 micrometer into the piezoelectric substrate, and do not affect the structural integrity of the piezoelectric substrate or the operation of the packaged surface acoustic wave device.

Laser-marked packaged surface acoustic wave devices are provided. The laser-marked packaged surface acoustic wave device may include a package structure encapsulating a surface acoustic wave device on a first side of a piezoelectric substrate. The opposite side of the piezoelectric substrate can be directly marked using a laser. The laser may be a deep ultraviolet laser. By directly marking the piezoelectric substrate itself, the use of a separate marking film can be avoided, making the packaged surface acoustic wave device thinner. When the laser has a wavelength readily absorbed by the piezoelectric substrate, a relatively shallow marking may be made in the piezoelectric substrate. The markings can extend less than 1 micrometer into the piezoelectric substrate, so as not to affect the structural integrity of the piezoelectric substrate or the operation of the packaged surface acoustic wave device.