Microfabricated ultrasonic transducer having individual cells with electrically isolated electrode sections

• US 10,512,936 B2
• Filed: 06/20/2018
• Issued: 12/24/2019
• Est. Priority Date: 06/21/2017
• Status: Active Grant

• Current Assignee: BFLY Operations, Inc. (Butterfly Network, Inc.)
• Original Assignee: Butterfly Network, Inc.
• Inventors: Alie, Susan A., Fife, Keith G., Lutsky, Joseph, Grosjean, David
• Primary Examiner(s): Ha, Nathan W
• Application Number:
  US16/012,999
• Publication Number:
  US 20180369862A1
• Time in Patent Office: 552 Days
• CPC Class Codes: B06B 1/0292 Electrostatic transducers, e.g. electret-type
• CPC Class Codes: B81B 2201/0271 Resonators; ultrasonic resonators
• CPC Class Codes: B81B 2203/0127 Diaphragms, i.e. structures separating two media that can control the passage from one medium to another; Membranes, i.e. diaphragms with filtering function
• CPC Class Codes: B81B 2203/0315 Cavities
• CPC Class Codes: B81B 2203/04 Electrodes
• CPC Class Codes: B81B 2207/015 the micromechanical device and the control or processing electronics being integrated on the same substrate
• CPC Class Codes: B81B 3/0021 Transducers for transforming electrical into mechanical energy or vice versa dynamo-electric machines H02K99/00; electrostatic machines H02N1/00; piezoelectric devices H10N30/00
• CPC Class Codes: B81B 3/0078 Constitution or structural means for improving mechanical properties not provided for in B81B3/007 - B81B3/0075
• CPC Class Codes: B81C 1/00238 Joining a substrate with an electronic processing unit and a substrate with a micromechanical structure
• CPC Class Codes: B81C 1/00246 Monolithic integration, i.e. micromechanical structure and electronic processing unit are integrated on the same substrate
• CPC Class Codes: B81C 2203/035 Soldering
• CPC Class Codes: B81C 2203/036 Fusion bonding
• CPC Class Codes: B81C 2203/0728 Pre-CMOS, i.e. forming the micromechanical structure before the CMOS circuit
• CPC Class Codes: B81C 2203/0792 Forming interconnections between the electronic processing unit and the micromechanical structure
• CPC Class Codes: G01N 2291/106 one or more transducer arrays
• CPC Class Codes: G01N 29/226 Handheld or portable devices
• CPC Class Codes: G01N 29/2406 Electrostatic or capacitive probes, e.g. electret or cMUT-probes

Abstract

An ultrasonic transducer includes a membrane, a bottom electrode, and a plurality of cavities disposed between the membrane and the bottom electrode, each of the plurality of cavities corresponding to an individual transducer cell. Portions of the bottom electrode corresponding to each individual transducer cell are electrically isolated from one another. Each portion of the bottom electrode corresponds to each individual transducer that cell further includes a first bottom electrode portion and a second bottom electrode portion, the first and second bottom electrode portions electrically isolated from one another.

Claims

1. An apparatus, comprising:

an ultrasonic transducer substrate having a membrane, a bottom electrode, and a plurality of cavities disposed between the membrane and the bottom electrode, each of the plurality of cavities corresponding to an individual transducer cell;

wherein portions of the bottom electrode corresponding to each individual transducer cell are electrically isolated from one another; and

each portion of the bottom electrode corresponding to each individual transducer cell further comprising a first bottom electrode portion and a second bottom electrode portion, the first and second bottom electrode portions electrically isolated from one another;

first trench isolation regions disposed within the bottom electrode and configured to electrically isolate each individual transducer cell from one another; and

second trench isolation regions disposed within the bottom electrode and configured to electrically isolate the first and second bottom electrode portions of an individual transducer cell from one another;

the apparatus further comprising an electrical substrate bonded to the ultrasonic transducer substrate.

2. The apparatus of claim 1, wherein the membrane serves as a top electrode for each of the individual transducer cells.

3. The apparatus of claim 1, wherein the first and second bottom electrode portions of an individual transducer cell are separately electrically addressable from one another.

4. The apparatus of claim 1, wherein the first bottom electrode portion comprises an inner bottom electrode with respect to a diameter of the transducer cell, and the second bottom electrode portion comprises an outer bottom electrode with respect to the diameter of the transducer cell.

5. The apparatus of claim 1, wherein the electrical substrate comprises one of:

a CMOS substrate, an analog circuit substrate, an interposer substrate, a printed circuit board (PCB) substrate, and a flexible substrate.

6. The apparatus of claim 5, wherein:

the electrical substrate comprises a CMOS substrate;

one of the first bottom electrode portion and the second bottom electrode portion is configured to perform a transmit function of the apparatus; and

the other of the first bottom electrode portion and the second bottom electrode portion is configured to perform a receive function of the apparatus.