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EP4545191A9 - Dispositif à ultrasons - Google Patents

Dispositif à ultrasons Download PDF

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Publication number
EP4545191A9
EP4545191A9 EP23205484.1A EP23205484A EP4545191A9 EP 4545191 A9 EP4545191 A9 EP 4545191A9 EP 23205484 A EP23205484 A EP 23205484A EP 4545191 A9 EP4545191 A9 EP 4545191A9
Authority
EP
European Patent Office
Prior art keywords
piezoelectric
moveable
cmos
ultrasound device
ultrasound
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP23205484.1A
Other languages
German (de)
English (en)
Other versions
EP4545191A1 (fr
Inventor
Greg Mcavoy
Mark Culleton
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
3c Project Technologies Ltd
Original Assignee
3c Project Technologies Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 3c Project Technologies Ltd filed Critical 3c Project Technologies Ltd
Priority to EP23205484.1A priority Critical patent/EP4545191A1/fr
Priority to PCT/EP2024/079988 priority patent/WO2025087992A1/fr
Publication of EP4545191A1 publication Critical patent/EP4545191A1/fr
Publication of EP4545191A9 publication Critical patent/EP4545191A9/fr
Pending legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
    • B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
    • B06B1/06—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction
    • B06B1/0644—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using a single piezoelectric element
    • B06B1/0662—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using a single piezoelectric element with an electrode on the sensitive surface
    • B06B1/0666—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using a single piezoelectric element with an electrode on the sensitive surface used as a diaphragm
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
    • B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
    • B06B1/0207—Driving circuits
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
    • B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
    • B06B1/06—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction
    • B06B1/0607—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using multiple elements
    • B06B1/0622—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using multiple elements on one surface

Definitions

  • Ultrasound devices are used in many different technical fields including medical imaging, drug delivery devices, non-destructive testing, gesture recognition and fingerprint sensors. For many applications within these technical fields, there is a need for miniaturised ultrasound devices.
  • PMUTs piezoelectric micromachined ultrasonic transducers
  • PMUTs typically include a thin piezoelectric film sandwiched between two electrodes and arranged above a cavity defined by a substrate. Piezoelectric materials can convert electrical energy into mechanical energy and vice versa. Considering PMUT devices in particular, motion of the piezoelectric film can be used to generate and/or sense ultrasound waves.
  • the piezoelectric body may comprise at least one piezoelectric material processable at a temperature below 450°C.
  • piezoelectric materials that are processable at temperatures below 450°C include aluminium nitride (AIN), zinc oxide (ZnO), and/or scandium aluminium nitride (ScAIN).
  • CMOS components can be damaged at temperatures greater than 450°C.
  • the piezoelectric element may comprise an inner portion and an outer portion.
  • the inner portion of the piezoelectric element comprises an inner piezoelectric body and a pair of inner electrodes; and the outer portion of the piezoelectric element comprises an outer piezoelectric body, and a pair of outer electrodes.
  • Each of the inner portion and the outer portion can transmit and/or receive ultrasound.
  • the ultrasound device is configured so that a first potential difference can be applied between the inner pair of electrodes to cause deflection of the inner piezoelectric body in a first direction and a second potential difference can be applied between the outer pair of electrodes to cause deflection of the outer piezoelectric body in a second direction opposite said first direction.
  • the wall of the cavity defined by the moveable piezoelectric diaphragm is continuous. That is, the moveable piezoelectric diaphragm extends across a full side of the cavity.
  • the additional layer may be provided directly on the first surface of the substrate.
  • the additional layer may be provided directly on the first surface of the substrate and one of the first and second electrodes provided between the additional layer and the piezoelectric body.
  • the additional layer may define the at least part of the wall of the cavity defined by the moveable piezoelectric membrane. Providing this additional layer facilitates more controlled oscillation of the piezoelectric diaphragm (i.e., an oscillation with a better defined characteristic).
  • at least part of the CMOS metallisation layer may be integrally provided within the additional layer.
  • the additional layer may comprise oxides, nitrides, oxynitrides or laminates.
  • the at least one piezoelectric element is one of a plurality of piezoelectric elements arranged in an array
  • the ultrasound device further comprises an additional layer on the first surface of the substrate, wherein each moveable piezoelectric diaphragm comprises at least part of the additional layer, wherein the additional layer defines the at least part of the wall of each cavity defined by the respective moveable piezoelectric diaphragm, and optionally wherein at least part of the CMOS metallisation layer is integrally provided within the additional layer and/or optionally wherein the additional layer comprises CMOS oxide.
  • the CMOS metallisation layer comprises conductive connections extending from at least one of the plurality of transistors to at least one of the first and second electrodes of a respective piezoelectric element, and optionally wherein the lengths of the conductive connections are consistent.
  • the array comprises a first zone having a first side and a second side opposite to the first side, wherein the plurality of piezoelectric elements are arranged into rows, wherein the conductive connections extend into the array from one or both of the first and second sides between the rows of piezoelectric elements, and optionally wherein the first zone is elongate and the first and second sides correspond to the long sides along the length of the first zone.
  • each of the piezoelectric elements can receive signals transmitted through the conductive connections (e.g., drive waveforms) at very similar times. This improves the uniformity of the ultrasound response when using an array of elements.
  • the first zone comprises at least a first, a second and third row of piezoelectric elements, wherein a first subset of the conductive connections extend between piezoelectric elements of the first and second row to different respective piezoelectric elements along the length of the second row, and optionally, wherein a second subset of the conductive connections extend between piezoelectric elements of the second and third row to different respective piezoelectric elements along the length of the second row.
  • the first zone comprises at least a first, a second and a third row of piezoelectric elements (typically without other rows in between) wherein a plurality of (and typically at least four) conductive connections extend between piezoelectric elements of the first and second row to different respective piezoelectric elements along the length of the second row, typically wherein a plurality of (and typically at least four) conductive connections extend between piezoelectric elements of the second and third row to different respective piezoelectric elements along the length of the second row a compact wiring arrangements that facilitates device miniaturisation is possible.
  • At least part of the CMOS control circuit is arranged in a column adjacent to at least one of the first and second sides of the first zone.
  • CMOS control circuit By providing at least part of the CMOS control circuit in a column adjacent to at least one of the first and second sides of the first zone in combination with conductive connections extending between piezoelectric elements from the CMOS circuitry it is possible to manufacture an ultrasound device having a small form-factor more conveniently.
  • the CMOS control circuit comprises a drive circuit configured to actuate each moveable piezoelectric diaphragm of at least a subset of the plurality of piezoelectric elements such that an ultrasound signal is transmitted;
  • CMOS control circuit comprising a drive circuit and a receive circuit on the same surface as the MEMS device it is possible to provide a highly integrated and compact ultrasound device.
  • these circuits By providing these circuits in a column adjacent to at least one of the first and second sides of the first zone, the size of the ultrasound device can be further reduced.
  • delay circuitry it is possible to focus the ultrasound beam transmitted from the ultrasound device. This can provide improved resolution for imaging applications, and improved energy deposition for therapeutic applications.
  • apodisation circuitry the frequency content of the transmitted pulse can be better controlled - providing improved signal quality for imaging applications. It is particularly advantageous to provide this circuit in the column adjacent at least one of the first and second sides of the first zone because this makes it possible to provide a particularly compact ultrasound device.
  • the CMOS control circuit comprises amplification circuitry for amplifying the received ultrasound signal
  • the wearable device is a patch.
  • a patch that can be worn on a user's arm.
  • the method may involve forming the cavities using a deep reactive-ion etching (DRIE) process.
  • DRIE deep reactive-ion etching
  • the DRIE etching may be carried out from the backside of the substrate, and optionally also from the frontside of the substrate.
  • a deep trench isolation structure is provided in the substrate for defining the walls of the cavity.
  • the ultrasound device comprises a plurality of piezoelectric elements and the CMOS control circuit comprises apodisation circuitry, wherein the method involves transmitting a first ultrasound signal from one piezoelectric element and a second ultrasound signal from a second piezoelectric element, wherein the amplitude of the first ultrasound signal is different from the amplitude of the second ultrasound signal.
  • FIG 1 is a schematic representation of an ultrasound device 100 having a piezoelectric element.
  • the ultrasound device comprises a semiconductor substrate 110 having a first surface 112 opposite to a second surface 114.
  • the ultrasound device 100 includes a CMOS control circuit comprising a plurality of transistors 120 integrally provided within the first surface 112 and a CMOS metallisation layer 130 provided on the first surface 112.
  • the piezoelectric element comprises a moveable piezoelectric diaphragm including a piezoelectric body 150, a first electrode 152 and a second electrode 154 each arranged on the first surface 112.
  • the moveable piezoelectric diaphragm also includes an additional layer 160 (made from the same material as the rest of the substrate, in this embodiment).
  • the CMOS metallisation layer 230 is provided integrally with the CMOS oxide layer 260, and comprises conductive connections 232, 234 extending from the plurality of transistors 220 to the first electrode 252.
  • Part of the metallisation layer 230 is provided within the moveable piezoelectric diaphragm, i.e., the part of the piezoelectric element that deforms into the cavity when in use.
  • a cavity 440 is defined in part by the moveable piezoelectric diaphragm and in part by the substrate 410.
  • the ultrasound device also includes a protective layer 470.
  • the moveable piezoelectric diaphragm does not extend across the full side of the cavity (i.e., it is discontinuous).
  • Each of the first electrode 452, the second electrode 454, and the piezoelectric body 450 are annular and arranged concentrically.
  • the additional layer 460 and protective layer 470 are also discontinuous such that a channel 490 is defined through the moveable piezoelectric diaphragm - thereby increasing the flexibility of the piezoelectric diaphragm.
  • FIG 6 is a schematic representation of an ultrasound device 600, which is similar to the ultrasound device 100 shown in Figure 1 .
  • the ultrasound device 600 comprises a substrate 610 having a first surface 612 and a second surface 614.
  • the ultrasound device 600 includes a protective layer 670 and a CMOS control circuit including a plurality of transistors 620 and a CMOS metallisation layer 630.
  • the CMOS metallisation layer 630 includes conductive connections 632, 634.
  • the piezoelectric element comprises a moveable piezoelectric diaphragm including a piezoelectric body 650, a first electrode 652, a second electrode 654 and an additional layer 660.
  • a cavity 640 is defined by the moveable piezoelectric diaphragm and the substrate 610.
  • the ultrasound device 600 further includes a buried oxide layer 680.
  • the buried oxide layer 680 makes it possible to operate the CMOS components at a higher voltage - thereby facilitating greater deflection of the moveable piezoelectric diaphragm.
  • the ultrasound device 700 further comprises deep trench isolation structures to define the cavity 740 dimensions.
  • the ultrasound device 700 also includes a notch 790 in the additional layer 760 and having a CMOS metal layer 792 as an etch stop. Having a notch 790, at least partly within the moveable piezoelectric diaphragm, affects the frequency response of the ultrasound device 700.
  • FIG 8 is a schematic representation of an ultrasound device 800, according to an embodiment of the invention.
  • the ultrasound device 800 comprises a substrate 810 having a first surface 812 and a second surface 814.
  • the ultrasound device 800 includes a cavity 840, an additional layer 860, a protective layer 870, a plurality of transistors 820, and a CMOS metallisation layer 830 including conductive connections 832, 834.
  • the moveable piezoelectric diaphragm includes a piezoelectric element having an inner portion and an outer portion.
  • the inner portion comprises an inner piezoelectric body 850b, a first inner electrode 852b, and a second inner electrode 854b.
  • the outer portion comprises an outer piezoelectric body 850a, a first outer electrode 852a, and a second outer electrode 854a.
  • the inner portion is circular and the outer portion is annular.
  • the inner and outer piezoelectric elements are arranged concentrically.
  • each of the inner portion and the outer portion can transmit and/or receive ultrasound.
  • a first potential difference can be applied between the inner pair of electrodes 852b, 854b and a second potential difference can be applied between the outer pair of electrodes 852a, 854a to cause deflection of the inner piezoelectric body 850b in a first direction and to cause deflection of the outer piezoelectric body 850a in a second direction opposite said first direction.
  • FIG 10 is a schematic representation of an ultrasound device 1000 according to an embodiment of the invention.
  • the ultrasound device 1000 comprises an array of piezoelectric elements arranged in rows.
  • the array includes an elongate zone 1020 having a first side 1022 and a second side 1024.
  • the ultrasound device comprises a plurality of transistors 1010 is arranged in a column adjacent to the first side 1022 of the elongate zone 1020.
  • Conductive connections 1030 from the plurality of transistors 1010 extend into the array from the first side 1022. In use, waveforms can be conducted between the plurality of transistors 1010 and each piezoelectric element.
  • Figure 11 is a schematic representation of part of an ultrasound device 1100 according to an embodiment of the invention.
  • the ultrasound device 1100 comprises an array of piezoelectric elements 1120 arranged in rows 1110a-c.
  • Conductive connections 1130 extend into the array from a first side of the array. It should be understood that Figure 11 is rotated by 90° relative to Figure 10 . As show in Figure 11 , a subset of the conductive connections extend between the elements of the adjacent rows to different respect piezoelectric elements along the length of each row 1110a-c.
  • Figure 12 is a schematic representation of a method 1200 of manufacturing an ultrasound device, according to an embodiment of the invention.
  • the method involves a step 1220 of forming n cavities within a substrate.
  • the cavities are provided using a DRIE etch procedure from the backside (i.e., the opposite second surface) of the substrate.
  • the method involves etching from the frontside (i.e., the first surface) and the backside. Buried oxide and deep trench isolation structures can be used to define the cavity dimensions.
  • the method also includes a step 1230 of forming a CMOS metallisation layer on the first surface.
  • the CMOS metallisation layer is also formed by standard processes such as ion implantation chemical vapour deposition, physical vapour deposition, etching, chemical-mechanical planarization and/or electroplating.
  • Figure 13 is a schematic representation of a method of using an ultrasound device according to an embodiment of the invention.
  • Figure 13 shows a method involving transmitting an ultrasound signal and receiving an ultrasound signal (e.g., an ultrasound signal generated by reflection of the transmitted ultrasound signal from another structure).
  • an ultrasound signal e.g., an ultrasound signal generated by reflection of the transmitted ultrasound signal from another structure.
  • the method involves a step of generating drive waveforms 1310 using at least a subset of the plurality of transistors. Typically, one drive waveform is generated for each piezoelectric element of the ultrasound device.
  • the method also includes a step of introducing delays to the drive waveforms 1320. The drive waveforms are delayed based on the relative positions of the piezoelectric elements on the array so that a focussed ultrasound beam is transmitted from the ultrasound device. In other embodiments, no such focussing is provided and plane waves are transmitted from the ultrasound device.
  • the method also involves an apodisation step 1330.
  • the method involves a step of sensing the membrane movement 1350.
  • Ultrasound signal incident on each moveable piezoelectric diaphragm causes that diaphragm to move.
  • An electrical signal is generated based on the movement of the diaphragm.
  • the method further involves an amplification step 1360. This step involves amplification of the electrical signal received from each piezoelectric element. By providing the amplification circuitry on the same surface as the MEMs components, noise propagation through the electrical circuitry is limited.
  • the method also involves a beamforming step 1370. It will be understood that various beamforming methods can be used.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
EP23205484.1A 2023-10-24 2023-10-24 Dispositif à ultrasons Pending EP4545191A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP23205484.1A EP4545191A1 (fr) 2023-10-24 2023-10-24 Dispositif à ultrasons
PCT/EP2024/079988 WO2025087992A1 (fr) 2023-10-24 2024-10-23 Dispositif à ultrasons

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP23205484.1A EP4545191A1 (fr) 2023-10-24 2023-10-24 Dispositif à ultrasons

Publications (2)

Publication Number Publication Date
EP4545191A1 EP4545191A1 (fr) 2025-04-30
EP4545191A9 true EP4545191A9 (fr) 2025-07-09

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP23205484.1A Pending EP4545191A1 (fr) 2023-10-24 2023-10-24 Dispositif à ultrasons

Country Status (2)

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EP (1) EP4545191A1 (fr)
WO (1) WO2025087992A1 (fr)

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101662989B (zh) * 2006-11-03 2013-10-30 研究三角协会 使用挠曲模式压电换能器的增强的超声成像探头
WO2016011172A1 (fr) * 2014-07-16 2016-01-21 Chirp Microsystems Transducteurs ultrasonores micro-usinés piézoélectriques utilisant deux substrats liés
WO2017065691A1 (fr) * 2015-10-14 2017-04-20 Agency For Science, Technology And Research Agencement de dispositif
US10325915B2 (en) * 2016-05-04 2019-06-18 Invensense, Inc. Two-dimensional array of CMOS control elements
MY191624A (en) * 2017-09-29 2022-07-04 Silterra Malaysia Sdn Bhd Monolithic integration of pmut on cmos
JP2023538971A (ja) * 2020-09-01 2023-09-12 スリーシー プロジェクト マネージメント リミテッド 一体化されたｃｍｏｓ回路を有するｍｅｍｓデバイス

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Publication number Publication date
WO2025087992A1 (fr) 2025-05-01
EP4545191A1 (fr) 2025-04-30

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