# US 11,992,839 B2 · Acoustic resonator device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,992,839 B2 - Document ID: US11992839B2 - Status: Granted - Kind: B2 - Application number: 17/749,002 - Filed: 2022-05-19 - Published: 2022-09-01 - Granted: 2024-05-28 - Earliest claimed: 2019-05-06 - Assignees: Qorvo US, Inc. - Applicants: Qorvo US, Inc. - Inventors: Rio Rivas; Kevin McCarron; Matthew Wasilik; David Doerr - Web page: https://patentgrep.com/patent/US11992839B2 ## CPC - B01L 3/502707: {characterised by the manufacture of the container or its components} - B01L 3/50273: {characterised by the means or forces applied to move the fluids} - G01N 29/022: {Fluid sensors based on microsensors, e.g. quartz crystal-microbalance [QCM], surface acoustic wave [SAW] devices, tuning forks, cantilevers, flexural plate wave [FPW] devices (microdevices per se B81B)} - G01N 29/036: by measuring frequency or resonance of acoustic waves - G01N 29/222: {Constructional or flow details for analysing fluids (optoacoustic fluid cells G01N29/2425)} - G01N 29/2462: {Probes with waveguides, e.g. SAW devices} - B01L 2400/0436: acoustic forces, e.g. surface acoustic waves [SAW] - G01N 2291/0255: (Bio)chemical reactions, e.g. on biosensors - G01N 2291/0256: Adsorption, desorption, surface mass change, e.g. on biosensors - G01N 2291/0426: Bulk waves, e.g. quartz crystal microbalance, torsional waves - H03H 3/02: for the manufacture of piezoelectric or electrostrictive resonators or networks (H03H3/08 takes precedence) - B01L: CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) ## Abstract Methods of fabricating a bulk acoustic wave resonator structure for a fluidic device. The methods can include a first step of disposing a first conductive material over a portion of a first surface of a substrate to form at least a portion of a first electrode, the substrate having a second surface opposite the first surface. Then, a piezoelectric material may be disposed over the first electrode. Next, a second conductive material can be disposed over the piezoelectric material to form at least a portion of a second electrode. The second conductive material extends substantially parallel to the first surface of the substrate and the second conductive material at least partially extends over the first conductive material. The overlapping region of the first conductive material, the piezoelectric material, and the second conductive material form a bulk acoustic wave resonator, the bulk acoustic wave resonator having a first side and an opposing second side. An acoustic energy management structure is then disposed over a first side of the bulk acoustic wave resonator. Next a third conductive material is disposed over a portion of the second conductive material that extends beyond the bulk acoustic wave resonator, wherein the third conductive material forms an interconnect extending above the acoustic energy management structure in a direction substantially perpendicular to the first surface of the substrate. Finally a portion of the second surface of the substrate is removed to expose a chemical mechanical connection at the first electrode at a second side of the bulk wave acoustic resonator. Devices formed thereby are also included. ## Claims ### Claim 1 A method of fabricating a bulk acoustic wave resonator structure for a fluidic device comprising: disposing a first conductive material over a portion of a first surface of a substrate to form at least a portion of a first electrode, the substrate having a second surface opposite the first surface; disposing a piezoelectric material over the first electrode; disposing a second conductive material over the piezoelectric material to form at least a portion of a second electrode, wherein the second conductive material extends substantially parallel to the first surface of the substrate, the second conductive material at least partially extending over the first conductive material, wherein an overlapping region of the first conductive material, the piezoelectric material, and the second conductive material forms a bulk acoustic wave resonator, the bulk acoustic wave resonator having a first side and an opposing second side; disposing an acoustic energy management structure over a first side of the bulk acoustic wave resonator; and removing a portion of the second surface of the substrate to expose a chemical mechanical connection at the first electrode at a second side of the bulk acoustic wave resonator. ### Claim 2 (depends on 1) The method of claim 1, wherein disposing the acoustic energy management structure over a first side of the bulk acoustic wave resonator comprises forming at least one wall structure and a roof from a photo imageable material to define an air cavity over the bulk acoustic wave resonator. ### Claim 3 (depends on 2) The method of claim 2, wherein the roof has an area from 100 micrometers2 to 500,000 micrometers2. ### Claim 4 (depends on 1) The method of claim 1, wherein disposing the acoustic energy management structure over a first side of the bulk acoustic wave resonator comprises disposing layers of material to form an acoustic mirror over the bulk acoustic wave resonator. ### Claim 5 (depends on 1) The method of claim 1, further comprising: disposing and patterning a sacrificial layer on the substrate; and disposing a passivation layer over the sacrificial layer, wherein the passivation layer is disposed prior to disposing the first conductive material, wherein disposing the first conductive material over the portion of the first surface of the substrate comprises patterning the first conductive material such that the first conductive material aligns over the sacrificial layer, and wherein the passivation layer forms at least a portion of the first electrode in a region overlapping the first conductive material. ### Claim 6 (depends on 5) The method of claim 5, further comprising: removing the sacrificial layer adjacent the passivation layer. ### Claim 7 (depends on 1) The method of claim 1, wherein removing a portion of the second surface of the substrate comprises reducing a thickness of the substrate. ### Claim 8 (depends on 7) The method of claim 7, wherein the thickness of the substrate is reduced to 200 micrometers to 400 micrometers thick. ### Claim 9 (depends on 1) The method of claim 1, further comprising mounting the bulk acoustic wave resonator structure to a base, wherein mounting the bulk acoustic wave resonator structure comprises electrically coupling the bulk acoustic wave resonator structure to the base. ### Claim 10 (depends on 1) The method of claim 1 wherein disposing the second conductive material comprises depositing the second conductive material over the piezoelectric material and patterning the second conductive material after deposition. ### Claim 11 A method of fabricating a bulk acoustic wave resonator structure for a fluidic device comprising: disposing a first conductive material over a portion of a first surface of a substrate to form at least a portion of a first electrode, the substrate having a second surface opposite the first surface; disposing a piezoelectric material over the first electrode; disposing a second conductive material over the piezoelectric material to form at least a portion of a second electrode, wherein the second conductive material extends substantially parallel to the first surface of the substrate, the second conductive material at least partially extending over the first conductive material, wherein an overlapping region of the first conductive material, the piezoelectric material, and the second conductive material forms a bulk acoustic wave resonator, the bulk acoustic wave resonator having a first side and an opposing second side; disposing an acoustic energy management structure over a first side of the bulk acoustic wave resonator; and disposing a third conductive material over a portion of the second conductive material that extends beyond the bulk acoustic wave resonator, wherein the third conductive material forms an interconnect extending above the acoustic energy management structure in a direction substantially perpendicular to the first surface of the substrate. ### Claim 12 (depends on 11) The method of claim 11, wherein disposing the acoustic energy management structure over a first side of the bulk acoustic wave resonator comprises forming at least one wall structure and a roof from a photo imageable material to define an air cavity over the bulk acoustic wave resonator. ### Claim 13 (depends on 12) The method of claim 12, wherein the roof has an area from 100 micrometers2 to 500,000 micrometers2. ### Claim 14 (depends on 12) The method of claim 12 wherein disposing the second conductive material comprises depositing the second conductive material over the piezoelectric material and patterning the second conductive material after deposition. ### Claim 15 (depends on 11) The method of claim 11, wherein disposing the acoustic energy management structure over a first side of the bulk acoustic wave resonator comprises disposing layers of material to form an acoustic mirror over the bulk acoustic wave resonator. ### Claim 16 (depends on 11) The method of claim 11, further comprising: disposing and patterning a sacrificial layer on the substrate; and disposing a passivation layer over the sacrificial layer, wherein the passivation layer is disposed prior to disposing the first conductive material, wherein disposing the first conductive material over the portion of the first surface of the substrate comprises patterning the first conductive material such that the first conductive material aligns over the sacrificial layer, and wherein the passivation layer forms at least a portion of the first electrode in a region overlapping the first conductive material. ### Claim 17 (depends on 16) The method of claim 16, further comprising: removing the sacrificial layer adjacent the passivation layer. ### Claim 18 (depends on 11) The method of claim 11, further comprising mounting the bulk acoustic wave resonator structure to a base, wherein mounting the bulk acoustic wave resonator structure comprises at least electrically coupling the interconnect to the base. ### Claim 19 (depends on 11) The method of claim 11 wherein the interconnect comprises a copper pillar. ### Claim 20 (depends on 19) The method of claim 19 wherein the copper pillar is plated with tin.