A method and structure for a transfer process for an acoustic resonator device. In an example, a bulk acoustic wave resonator (BAWR) with an air reflection cavity is formed. A piezoelectric thin film is grown on a crystalline substrate. Patterned electrodes are deposited on the surface of the piezoelectric film. An etched sacrificial layer is deposited over the electrodes and a planarized support layer is deposited over the sacrificial layer. The device can include a dielectric protection layer (DPL) that protects the piezoelectric layer from etching processes that can produce rough surfaces and reduces parasitic capacitance around the perimeter of the resonator when the DPL's dielectric constant is lower than that of the piezoelectric layer. The DPL can be configured between the top electrode and the piezoelectric layer, between the bottom electrode and the piezoelectric layer, or both.

An electronic device includes a first substrate and a second substrate. A side wall joins the first substrate to the second substrate. The side wall includes a first alloy layer of a first metal and a second metal bonded directly to an upper surface of the first substrate and a second alloy layer of the first metal and a third metal disposed on top of the first alloy layer and bonded directly to a lower surface of the second substrate, the second metal and the third metal being different from each other and from the first metal. An electronic circuit is disposed on the lower surface of the second substrate within a cavity defined by the lower surface of the first substrate, the upper surface of the second substrate, and the side wall.

A method and structure for a transfer process for an acoustic resonator device. In an example, a bulk acoustic wave resonator (BAWR) with an air reflection cavity is formed. A piezoelectric thin film is grown on a crystalline substrate. A first patterned electrode is deposited on the surface of the piezoelectric film. An etched sacrificial layer is deposited over the first electrode and a planarized support layer is deposited over the sacrificial layer, which is then bonded to a substrate wafer. The crystalline substrate is removed and a second patterned electrode is deposited over a second surface of the film. The sacrificial layer is etched to release the air reflection cavity. Also, a cavity can instead be etched into the support layer prior to bonding with the substrate wafer. Alternatively, a reflector structure can be deposited on the first electrode, replacing the cavity.

A method for producing a plurality of piezoelectric multilayer components is disclosed. In an embodiment, a method for producing a plurality of piezoelectric multilayer components includes grinding the piezoelectric multilayer components without an addition of an abrasive by rubbing the piezoelectric multilayer components against one another so that a material abrasion of the piezoelectric multilayer components is carried out.

A vibration detection element (10) includes substrates (1 to 3), a support member (22), a support member (32), and an oscillator (4). The substrates (1 to 3) have a space portion (SP) having a bottom surface (21A) and a bottom surface (31A) opposed to the bottom surface (21A). The support member (22) protrudes from the bottom surface (21A) toward the bottom surface (31A) of the space portion (SP). The support member (32) protrudes from the bottom surface (31A) toward the bottom surface (21A) of the space portion. The oscillator (4) is disposed in contact with the support member (22) or the support member (32) and capable of vibrating in the space portion (SP) and has a thickness less than 10 μm. The support members (22, 32) each include multiple supports which prevent the oscillator (4) from contacting the bottom surface (21A) or the bottom surface (31A).

A ceramic substrate is formed of polycrystalline ceramic and has a supporting main surface. At the supporting main surface of the ceramic substrate, the mean of grain sizes of the polycrystalline ceramic is 0.5 μm or more and less than 15 μm and the standard deviation of the grain sizes is less than 1.5 times the mean.

A process for fabricating a substrate for a radiofrequency device by joining a piezoelectric layer to a carrier substrate by way of an electrically insulating layer, the piezoelectric layer having a rough surface at its interface with the electrically insulating layer, the process being characterized in that it comprises the following steps: providing a piezoelectric substrate having a rough surface for reflecting a radiofrequency wave, depositing a dielectric layer on the rough surface of the piezoelectric substrate, providing a carrier substrate, depositing a photo-polymerizable adhesive layer on the carrier substrate, bonding the piezoelectric substrate to the carrier substrate by way of the dielectric layer and of the adhesive layer, in order to form an assembled substrate, irradiating the assembled substrate with a light flux in order to polymerize the adhesive layer, the adhesive layer and the dielectric layer together forming the electrically insulating layer.

A bonding layer 3 is formed over a piezoelectric material substrate, and the bonding layer is made of one or more materials selected from the group consisting of silicon nitride, aluminum nitride, alumina, tantalum pentoxide, mullite, niobium pentoxide and titanium oxide. A neutralized beam is irradiated onto a surface of the bonding layer and a surface of a supporting body to activate the surface of the bonding layer and the surface of the supporting body. The surface of the bonding layer and the surface of the supporting body are bonded by direct bonding.

A device including a piezoelectric substrate, an interdigital transducer (IDT), and an antireflective structure is disclosed herein. The piezoelectric substrate has a front-side surface and a smoothed back-side surface. The IDT is on the front-side surface of the piezoelectric substrate. The antireflective structure is over at least a portion of the smoothed back-side surface of the piezoelectric substrate. By having the antireflective structure on at least a portion of the smoothed back-side surface of the piezoelectric substrate, reflection of spurious bulk acoustic waves toward the front-side surface of the piezoelectric substrate can be reduced and/or eliminated to lessen interference with surface acoustic waves. The reduction and/or elimination of spurious bulk acoustic waves allows the device to forego conventional roughening of the back-side surface of the piezoelectric substrate, thereby reducing fractures at the back-side surface and allowing for singulation techniques capable of producing smaller die sizes.

An electronic device, such as a filter, includes a first substrate having a bottom surface and a top surface, a first side wall of a certain height being formed along a periphery of the bottom surface to surround an electronic circuit disposed on the bottom surface, an external electrode formed on the top surface, the external electrode being connected to the electronic circuit by a via communicating with the bottom surface and a second substrate. The second substrate has a second side wall of a certain height formed along a periphery of a top surface, the second side wall being aligned and bonded with the first side wall to internally form a cavity defined between the bottom surface of the first substrate, the top surface of the second substrate, the first side wall, and the second side wall.