# US 12,191,837 B2 · Solidly-mounted transversely-excited film bulk acoustic device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,191,837 B2 - Document ID: US12191837B2 - Status: Granted - Kind: B2 - Application number: 17/520,687 - Filed: 2021-11-07 - Published: 2022-02-24 - Granted: 2025-01-07 - Earliest claimed: 2018-06-15 - Assignees: Murata Manufacturing Co., Ltd. - Applicants: Murata Manufacturing Co., Ltd. - Inventors: Ventsislav Yantchev; Bryant Garcia; Viktor Plesski; Soumya Yandrapalli; Robert B. Hammond; Patrick Turner; Jesson John - Web page: https://patentgrep.com/patent/US12191837B2 ## CPC - H03H 9/00: Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators (electro-acoustic transducers such as loudspeakers, microphones or gramophone pick-ups H04R; piezoelectric, electrostrictive or magnetostrictive devices with mechanical input or output, e.g. actuators or sensors, H10N30/00, H10N35/00) - H03H 9/02228: {Guided bulk acoustic wave devices or Lamb wave devices having interdigital transducers situated in parallel planes on either side of a piezoelectric layer} - H03H 3/02: for the manufacture of piezoelectric or electrostrictive resonators or networks (H03H3/08 takes precedence) - H03H 9/02031: {consisting of ceramic} - H03H 9/1014: {the enclosure being defined by a frame built on a substrate and a cap, the frame having no mechanical contact with the BAW device} - H03H 9/1071: {the enclosure being defined by a frame built on a substrate and a cap, the frame having no mechanical contact with the SAW device} - H03H 9/1085: {the enclosure being defined by a non-uniform sealing mass covering the non-active sides of the SAW device} - H03H 9/132: {characterized by a particular shape} - H03H 9/175: {Acoustic mirrors} - H03H 9/176: {consisting of ceramic material (H03H9/177, H03H9/178 take precedence)} - H03H 9/562: {comprising a ceramic piezoelectric layer} - H03H 9/564: {implemented with thin-film techniques} - H03H 9/568: {consisting of a ladder configuration} - H03H 2003/025: {the resonators or networks comprising an acoustic mirror} - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) ## Abstract Resonator and filter devices and methods of fabrication. A resonator chip includes a substrate, a piezoelectric plate, and an acoustic Bragg reflector between the substrate and a back surface of the piezoelectric plate. A conductor pattern on a front surface of the piezoelectric plate includes a first plurality of contact pads and an interdigital transducer (IDT). The IDT and the piezoelectric plate are configured such that a radio frequency signal applied to the IDT excites a shear primary acoustic mode within the piezoelectric plate. The acoustic Bragg reflector is configured to reflect the shear primary acoustic mode. An interposer has a second plurality of contact pads on a back surface. A seal connects a perimeter of the piezoelectric plate to a perimeter of the interposer. Each contact pad of the first plurality of contact pads is directly connected to a respective contact pad of the second plurality of contact pads. ## Claims ### Claim 1 An acoustic resonator device comprising: an acoustic resonator chip comprising: a substrate; a piezoelectric layer having front and back surfaces; a first conductor pattern on the front surface of the piezoelectric layer, the first conductor pattern comprising a first plurality of contact pads and an interdigital transducer (IDT), the IDT and the piezoelectric layer configured such that a radio frequency signal applied to the IDT excites a primary shear acoustic mode within the piezoelectric layer; and an acoustic Bragg reflector between a surface of the substrate and the back surface of the piezoelectric layer, the acoustic Bragg reflector configured to reflect the shear primary acoustic mode; an interposer comprising a second conductor pattern that includes a second plurality of contact pads on a surface of the interposer that faces the acoustic resonator chip; and a continuous metal seal around a perimeter of the piezoelectric layer and perimeter of the interposer, the continuous metal seal being spaced apart from the first and second plurality of contact pads and configured to seal the IDT in a cavity of the acoustic resonator device, wherein the interposer comprises a plurality of conductor layers with vias connecting the second plurality of contact pads to a third plurality of contact pads on a surface of the interposer that is not facing the IDT, wherein each contact pad of the first plurality of contact pads is connected to a respective contact pad of the second plurality of contact pads, and wherein at least one of the contact pads of the first plurality of contact pads is connected to at least one of the contact pads of the second plurality of contact pads by thermocompression or ultrasonic bonding. ### Claim 2 (depends on 1) The acoustic resonator device of claim 1, wherein the acoustic Bragg reflector is configured to reflect the primary shear acoustic mode over a frequency range comprising a resonance frequency and an anti-resonance frequency of the acoustic resonator device. ### Claim 3 (depends on 1) The acoustic resonator device of claim 1, wherein the seal comprises an adhesive material. ### Claim 4 (depends on 1) The acoustic resonator device of claim 1, wherein the interposer comprises a silicon base; and the vias are through silicon vias. ### Claim 5 (depends on 1) The acoustic resonator device of claim 1, wherein the interposer is a low temperature co-fired ceramic circuit card. ### Claim 6 (depends on 1) The acoustic resonator device of claim 1, wherein the interposer is a printed circuit board. ### Claim 7 (depends on 1) The acoustic resonator device of claim 1, wherein the interposer further comprises a recess facing the IDT. ### Claim 8 A filter device comprising: an acoustic resonator chip comprising: a substrate; a piezoelectric layer having front and back surfaces; a first conductor pattern on the front surface of the piezoelectric layer, the first conductor pattern comprising a first plurality of contact pads and interdigital transducers (IDTs) of a plurality of acoustic resonators comprising a shunt resonator and a series resonator; an acoustic Bragg reflector between a surface of the substrate and the back surface of the piezoelectric layer; a first dielectric layer on and between interleaved fingers of the IDT of the shunt resonator and having a first thickness; and a second dielectric layer on and between the interleaved fingers of the IDT of the series resonator and having a second thickness less than the first thickness; an interposer comprising a second conductor pattern having a second plurality of contact pads on a surface of the interposer that faces the acoustic resonator chip; and a continuous metal seal around a perimeter of the piezoelectric layer and a perimeter of the interposer, the continuous metal seal being spaced apart from the first and second plurality of contact pads and configured to seal the IDT in a cavity of the acoustic resonator device, wherein the interposer comprises a plurality of conductor layers, wherein each contact pad of the first plurality of contact pads is connected to a respective contact pad of the second plurality of contact pads, and wherein at least one of the contact pads of the first plurality of contact pads is connected to at least one of the contact pads of the second plurality of contact pads by thermocompression or ultrasonic bonding. ### Claim 9 (depends on 8) The filter device of claim 8, wherein: the piezoelectric layer and all of the IDTs are configured such that radio frequency signals applied to the IDTs excite respective primary shear acoustic modes in the piezoelectric layer, and the acoustic Bragg reflector is configured to reflect the respective primary shear acoustic modes excited by all of the IDTs. ### Claim 10 (depends on 9) The filter device of claim 9, wherein the acoustic Bragg reflector is configured to reflect the primary shear acoustic modes excited by all of the IDTs over a frequency range comprising a resonance frequency and an anti-resonance frequency of all of the plurality of acoustic resonators. ### Claim 11 (depends on 8) The filter device of claim 8, wherein the seal comprises an adhesive material. ### Claim 12 (depends on 8) The filter device of claim 8, wherein the interposer further comprises vias connecting the second plurality of contact pads to a third plurality of contact pads on a surface of the interposer that is not facing the IDTs. ### Claim 13 (depends on 12) The filter device of claim 12, wherein the interposer comprises a silicon base; and the vias are through silicon vias. ### Claim 14 (depends on 12) The filter device of claim 12, wherein the interposer is a low temperature co-fired ceramic circuit card. ### Claim 15 (depends on 12) The filter device of claim 12 wherein the interposer is a printed circuit board. ### Claim 16 (depends on 8) The filter device of claim 8, wherein the interposer further comprises a plurality of recesses in the surface of the interposer facing the IDTs of the plurality of acoustic resonators. ### Claim 17 A filter device comprising: an acoustic resonator chip comprising: a substrate; a piezoelectric layer having front and back surfaces; a first conductor pattern on the front surface of the piezoelectric layer, the first conductor pattern comprising a first plurality of contact pads and interdigital transducers (IDTs) of a plurality of acoustic resonators comprising a shunt resonator and a series resonator; an acoustic Bragg reflector between a surface of the substrate and the back surface of the piezoelectric layer; a first dielectric layer on and between interleaved fingers of the IDT of the shunt resonator and having a first thickness; and a second dielectric layer on and between the interleaved fingers of the IDT of the series resonator and having a second thickness less than the first thickness; an interposer comprising a second conductor pattern that includes a second plurality of contact pads on a surface of the interposer that faces the acoustic resonator chip; and a seal connecting the piezoelectric layer to the interposer to seal the shunt resonator and the series resonator within an internal cavity of filter device, wherein each contact pad of the first plurality of contact pads is connected to a respective contact pad of the second plurality of contact pads, wherein the interposer comprises a plurality of recesses in the surface of the interposer facing the IDTs of the plurality of acoustic resonators, and wherein each of the plurality of recesses has a depth such that a distance from a bottom of each recess to the respective IDT is greater than or equal to 15 microns and less than or equal to 100 microns.