An integrated circuit film bulk acoustic resonator (FBAR) device having multiple resonator thicknesses is formed on a common substrate in a stacked configuration. In an embodiment, a seed layer is deposited on a substrate, and one or more multi-layer stacks are deposited on the seed layer, each multi-layer stack having a first metal layer deposited on a first sacrificial layer, and a second metal layer deposited on a second sacrificial layer. The second sacrificial layer can be removed and the resulting space is filled in with a piezoelectric material, and the first sacrificial layer can be removed to release the piezoelectric material from the substrate and suspend the piezoelectric material above the substrate. More than one multi-layer stack can be added, each having a unique resonant frequency. Thus, multiple resonator thicknesses can be achieved on a common substrate, and hence, multiple resonant frequencies on that same substrate.

A bulk acoustic wave filter includes: a first bulk acoustic wave resonator including, in an order from bottom to top, a first cavity, a first bottom electrode, a first segment of a piezoelectric layer, and a first top electrode; a second bulk acoustic wave resonator disposed adjacent to the first bulk acoustic wave resonator, and including, in the order from bottom to top, a second cavity, a second bottom electrode, a second segment of the piezoelectric layer, and a second top electrode; a boundary structure surrounding the first cavity and the second cavity, the boundary structure including a boundary portion extending between and separating the first cavity and the second cavity, and the boundary portion being disconnected at a disconnection region; and a first release hole formed in the piezoelectric layer, and overlapping the disconnection region.

A bulk acoustic wave filter includes: a first bulk acoustic wave resonator including, in an order from bottom to top, a first cavity, a first bottom electrode, a first segment of a piezoelectric layer, and a first top electrode; a second bulk acoustic wave resonator disposed adjacent to the first bulk acoustic wave resonator, and including, in the order from bottom to top, a second cavity, a second bottom electrode, a second segment of the piezoelectric layer, and a second top electrode; a boundary structure surrounding the first cavity and the second cavity, the boundary structure including a boundary portion extending between and separating the first cavity and the second cavity, and the boundary portion being disconnected at a disconnection region; and a first release hole formed in the piezoelectric layer, and overlapping the disconnection region.

The disclosure provides a film bulk acoustic resonator and a manufacturing method therefor, and a film bulk acoustic wave filter, and relates to the technical field of resonators. The film bulk acoustic resonator includes a substrate, where the substrate is provided with two opposite protective walls protruding out of a surface of the substrate, a cavity is formed between the two protective walls, and an insulating layer is further arranged on one side, away from the cavity, of each protective wall on the substrate; and the film bulk acoustic resonator further includes a transducer stacking structure, where the transducer stacking structure covers the insulating layer, the cavity and the protective walls, and two sides, along a stacking direction, of the transducer stacking structure are in communication with the cavity and the outside respectively. With the cavity formed through the protective walls, the cavity being in communication with the outside, and the cavity formed by releasing corrosive substances to the cavity area from the outside, accurate control over cavity release machining is achieved, a process is simpler, cost is controlled, and a process period is shortened; an area proportion of the protective walls is small, and a chemical mechanical polishing (CMP) requirement is low, so as to advantageously improve a yield; and a structure of the film bulk acoustic resonator is built on the insulating layer, so as to advantageously reduce parasitic capacitance and resistance and improve comprehensive device performance.

The disclosure provides a film bulk acoustic resonator and a manufacturing method therefor, and a film bulk acoustic wave filter, and relates to the technical field of resonators. The film bulk acoustic resonator includes a substrate, where the substrate is provided with two opposite protective walls protruding out of a surface of the substrate, a cavity is formed between the two protective walls, and an insulating layer is further arranged on one side, away from the cavity, of each protective wall on the substrate; and the film bulk acoustic resonator further includes a transducer stacking structure, where the transducer stacking structure covers the insulating layer, the cavity and the protective walls, and two sides, along a stacking direction, of the transducer stacking structure are in communication with the cavity and the outside respectively. With the cavity formed through the protective walls, the cavity being in communication with the outside, and the cavity formed by releasing corrosive substances to the cavity area from the outside, accurate control over cavity release machining is achieved, a process is simpler, cost is controlled, and a process period is shortened; an area proportion of the protective walls is small, and a chemical mechanical polishing (CMP) requirement is low, so as to advantageously improve a yield; and a structure of the film bulk acoustic resonator is built on the insulating layer, so as to advantageously reduce parasitic capacitance and resistance and improve comprehensive device performance.

An acoustic device includes a plurality of bulk acoustic resonance structures. Each of the bulk acoustic resonance structures includes a substrate. The bulk acoustic resonance structure further includes a reflective structure, a first electrode layer, a piezoelectric layer and a second electrode layer stacked on the substrate in sequence. The bulk acoustic resonance structure further includes multiple protruding blocks located on the piezoelectric layer and circumferentially arranged around the second electrode layer, wherein the multiple protruding blocks have a preset distance from the second electrode layer, and the preset distance depends on a connection manner between the bulk acoustic resonance structure and other ones of multiple bulk acoustic resonance structures.

An acoustic device includes a plurality of bulk acoustic resonance structures. Each of the bulk acoustic resonance structures includes a substrate. The bulk acoustic resonance structure further includes a reflective structure, a first electrode layer, a piezoelectric layer and a second electrode layer stacked on the substrate in sequence. The bulk acoustic resonance structure further includes multiple protruding blocks located on the piezoelectric layer and circumferentially arranged around the second electrode layer, wherein the multiple protruding blocks have a preset distance from the second electrode layer, and the preset distance depends on a connection manner between the bulk acoustic resonance structure and other ones of multiple bulk acoustic resonance structures.

Provided are a band-stop filter and a multi-frequency band-stop filter. The band-stop filter includes at least one band-stop filtering unit; the at least one band-stop filtering unit includes an input port, an output port, at least two resonators, and at least one inductive element; and the first terminal of the first resonator is connected between the input port and the inductive element, and the first terminal of the second resonator is connected between the output port and the inductive element.

Provided are a band-stop filter and a multi-frequency band-stop filter. The band-stop filter includes at least one band-stop filtering unit; the at least one band-stop filtering unit includes an input port, an output port, at least two resonators, and at least one inductive element; and the first terminal of the first resonator is connected between the input port and the inductive element, and the first terminal of the second resonator is connected between the output port and the inductive element.

A BAW resonator with an improved lateral energy confinement is provided. The resonator has a bottom electrode in a bottom electrode layer, a top electrode in a top electrode layer and a piezoelectric layer between the bottom electrode layer and the top electrode layer. The piezoelectric layer comprises piezoelectric materials of different piezoelectric polarities.