Integration techniques for micromachined pMUT arrays and electronics using thermocompression bonding, eutectic bonding, and solder bonding

Patent metadata

Field	Value
Publication number	US-12263507-B2
Application number	US-202017095333-A
Country	US
Kind code	B2
Filing date	Nov 11, 2020
Priority date	May 14, 2018
Publication date	Apr 1, 2025
Grant date	Apr 1, 2025

Abstract

The present disclosure provides methods to integrate piezoelectric micromachined ultrasonic transducer (pMUT) arrays with an application-specific integrated circuit (ASIC) using thermocompression or eutectic/solder bonding. In an aspect, the present disclosure provides a device comprising a first substrate and a second substrate, the first substrate comprising a pMUT array and the second substrate comprising an electrical circuit, wherein the first substrate and the second substrate are bonded together using thermocompression, wherein any set of individual PMUTs of PMUT array is addressable. In another aspect, the present disclosure provides a device comprising a first substrate and a second substrate, the first substrate comprising a pMUT array and the second substrate comprising an electrical circuit, wherein the first substrate and the second substrate are bonded together using eutectic or solder bonding, wherein any set of individual PMUTs of the PMUT array is addressable.

First claim

What is claimed is:

1. A device comprising a first substrate and a second substrate, the first substrate comprising at least one piezoelectric micromachined ultrasonic transducer (pMUT) array having a plurality of pMUTs, the second substrate comprising a plurality of electrical circuits, wherein the first substrate and the second substrate are bonded together using thermocompression to form individual electrical connections on a one-to-one basis between each of the plurality of pMUTs of the first substrate and a respective one of the plurality of electrical circuits of the second substrate, wherein the individual electrical connections enable each pMUT to be individually addressable by the respective electrical circuit for facilitating control over each pMUT of the at least one pMUT array.

2. The device according to claim 1 , wherein the at least one pMUT array is configured to perform ultrasound imaging.

3. The device according to claim 1 , wherein the plurality of electrical circuits comprises an application-specific integrated circuit (ASIC).

4. The device according to claim 1 , wherein the first substrate comprises a wafer and the second substrate comprises a wafer, and wherein the first substrate and the second substrate are bonded together using thermocompression bonding to create a wafer-to-wafer bond.

5. The device according to claim 1 , wherein one of the first substrate or the second substrate comprises a die and one of the first substrate or second substrate comprises a wafer and the first substrate and the second substrate are bonded together using thermocompression bonding to create a die-to-wafer bond.

6. The device according to claim 1 , wherein the first substrate comprises a die and the second substrate comprises a die and the first substrate and the second substrate are bonded together using thermocompression bonding to creates a die-to-die bond.

7. The device according to claim 1 , wherein the thermocompression bonding is performed at a temperature of no more than about 350° C.

8. The device according to claim 7 , wherein the thermocompression bonding is performed at a temperature of no more than about 300° C.

9. The device according to claim 7 , wherein the thermocompression bonding comprises bonding together two metals of the same type selected from the group consisting of gold (Au), copper (Cu), and aluminum (Al).

10. A method of fabricating an integrated device, the method comprising:
(a) obtaining a first substrate comprising at least one piezoelectric micromachined ultrasonic transducer (pMUT) array having a plurality of pMUTs;
(b) obtaining a second substrate comprising a plurality of electrical circuits; and
(c) bonding together the first substrate and the second substrate using thermocompression to form an individual electrical connection between each pMUT of the first substrate and a respective electrical circuit of the second substrate, wherein the individual electrical connection enables each pMUT of the at least one pMUT array to be individually addressable by the respective electrical circuit for facilitating control each pMUT of the at least one pMUT array.

11. The method according to claim 10 , wherein the at least one pMUT array is configured to perform ultrasound imaging.

12. The method according to claim 10 , wherein the plurality of electrical circuits comprises an application-specific integrated circuit (ASIC).

13. The method according to claim 10 , wherein the thermocompression bonding comprises wafer-to-wafer bonding.

14. The method according to claim 10 , wherein the thermocompression bonding comprises die-to-wafer bonding.

15. The method according to claim 14 , wherein the die-to-wafer bonding uses an intermediate handle substrate and a temporary bonding layer.

16. The method according to claim 10 , wherein the thermocompression bonding comprises:
(a) temporarily bonding a wafer of the first substrate or the second substrate to a handle substrate using a temporary bonding layer;
(b) dicing the wafer on the handle substrate; and
(c) bonding the diced wafer to the other wafer of the first substrate or the second substrate using thermocompression.

17. The method according to claim 10 , wherein the thermocompression bonding comprises die-to-die bonding.

18. The method according to claim 10 , wherein the thermocompression bonding is performed at a temperature of no more than about 350° C.

19. The method according to claim 18 , wherein the thermocompression bonding is performed at a temperature of no more than about 300° C.

20. The method according to claim 18 , wherein the thermocompression bonding comprises bonding together two metals of the same type selected from the group consisting of gold (Au), copper (Cu), and aluminum (Al).

Assignees

• Exo Imaging Inc

Inventors

• Bircumshaw Brian
• Akkaraju Sandeep

Classifications

• H10W72/0198

  batch processes · CPC title

• H10W72/951

  Materials of bond pads · CPC title

• H10W72/29

  Bond pads specially adapted therefor · CPC title

• H10W72/07236

  Soldering or alloying · CPC title

• H10W72/072

  of bump connectors · CPC title