# US 2022/0274104 A1 · Acoustic resonator device

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- Number: US 2022/0274104 A1
- Document ID: US20220274104A1
- Status: Published application
- Kind: A1
- Application number: 17/749,002
- Filed: 2022-05-19
- Published: 2022-09-01
- Earliest claimed: 2019-05-06
- Assignees: Qorvo Biotechnologies, LLC
- Applicants: Qorvo Biotechnologies, LLC
- Inventors: Rio Rivas; Kevin McCarron; Matthew Wasilik; David Doerr
- Web page: https://patentgrep.com/patent/US20220274104A1

## 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 at position 1

1-32. (canceled)

### Claim 33

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 34 (depends on 33)

The method of claim 33, 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 35 (depends on 33)

The method of claim 33, 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 36 (depends on 33)

The method of claim 33, 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 37 (depends on 36)

The method of claim 36, further comprising:
removing the sacrificial layer adjacent the passivation layer.

### Claim 38 (depends on 33)

The method of claim 33, wherein removing a portion of the second surface of the substrate comprises reducing a thickness of the substrate.

### Claim 39 (depends on 38)

The method of claim 38, wherein the thickness of the substrate is reduced to 200 micrometers to 400 micrometers thick.

### Claim 40 (depends on 33)

The method of claim 33, 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 41

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 42 (depends on 41)

The method of claim 41, 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 43 (depends on 42)

The method of claim 42, wherein the roof has an area from 100 micrometers2 to 500,000 micrometers2.

### Claim 44 (depends on 41)

The method of claim 41, 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 45 (depends on 41)

The method of claim 41, 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 46 (depends on 45)

The method of claim 45, further comprising:
removing the sacrificial layer adjacent the passivation layer.

### Claim 47 (depends on 41)

The method of claim 41, 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 48

A bulk acoustic wave resonator structure comprising:
a bulk acoustic wave resonator arranged under a substrate, wherein the bulk acoustic wave resonator comprises a first electrode disposed over a portion of a first surface of a substrate, a piezoelectric material disposed over the first electrode, and a second electrode disposed over the piezoelectric material, wherein an overlapping region of the first electrode, the piezoelectric material, and the second electrode forms a bulk acoustic wave resonator;
an acoustic energy management structure disposed over a first side of the bulk acoustic wave resonator; and
an interconnect disposed over a portion of the second electrode extending beyond the bulk acoustic wave resonator, wherein the interconnect extends above a height of the acoustic energy management structure in a direction substantially perpendicular to the first surface of the substrate.

### Claim 49 (depends on 48)

The bulk acoustic wave resonator structure of claim 48, wherein the acoustic energy management structure comprises an air cavity comprising at least one wall and a roof comprising a photo imageable material.

### Claim 50 (depends on 49)

The bulk acoustic wave resonator structure of claim 49, wherein the roof has an area from 100 micrometers2 to 500,000 micrometers2.

### Claim 51 (depends on 48)

The bulk acoustic wave resonator structure of claim 48, wherein the acoustic energy management structure comprises an acoustic reflector.

### Claim 52 (depends on 48)

The bulk acoustic wave resonator structure of claim 48, further comprising a base, and
wherein the bulk acoustic wave resonator structure comprises a plurality of bulk acoustic wave resonators, each of the plurality of bulk acoustic wave resonators comprising an associated acoustic energy management structure and an interconnect for independently electrically coupling each of the plurality of bulk acoustic wave resonators to the base.