WO2022170805A1 - 一种微机电超声波换能器及阵列 - Google Patents
一种微机电超声波换能器及阵列 Download PDFInfo
- Publication number
- WO2022170805A1 WO2022170805A1 PCT/CN2021/131525 CN2021131525W WO2022170805A1 WO 2022170805 A1 WO2022170805 A1 WO 2022170805A1 CN 2021131525 W CN2021131525 W CN 2021131525W WO 2022170805 A1 WO2022170805 A1 WO 2022170805A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- electrode
- layer
- ultrasonic transducer
- pad
- microelectromechanical
- Prior art date
Links
- 238000000034 method Methods 0.000 claims abstract description 12
- 230000008569 process Effects 0.000 claims abstract description 11
- 229910052751 metal Inorganic materials 0.000 claims description 19
- 239000002184 metal Substances 0.000 claims description 19
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 12
- 239000000758 substrate Substances 0.000 claims description 12
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 11
- 229910052710 silicon Inorganic materials 0.000 claims description 11
- 239000010703 silicon Substances 0.000 claims description 11
- 238000004519 manufacturing process Methods 0.000 claims description 9
- 238000002604 ultrasonography Methods 0.000 claims description 9
- 230000005540 biological transmission Effects 0.000 claims description 8
- 239000000463 material Substances 0.000 claims description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 6
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 6
- 229910052782 aluminium Inorganic materials 0.000 claims description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 6
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims description 6
- 229910052737 gold Inorganic materials 0.000 claims description 6
- 239000010931 gold Substances 0.000 claims description 6
- 229910052697 platinum Inorganic materials 0.000 claims description 6
- 229910052718 tin Inorganic materials 0.000 claims description 6
- 239000007769 metal material Substances 0.000 claims description 5
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 claims description 4
- -1 scandium aluminum Chemical compound 0.000 claims description 4
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 3
- 235000012239 silicon dioxide Nutrition 0.000 claims description 3
- 239000000377 silicon dioxide Substances 0.000 claims description 3
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 3
- 230000005534 acoustic noise Effects 0.000 claims 1
- 230000010354 integration Effects 0.000 abstract description 8
- 238000005516 engineering process Methods 0.000 description 6
- 238000003384 imaging method Methods 0.000 description 6
- 230000009286 beneficial effect Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- 239000000919 ceramic Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000005284 excitation Effects 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 238000003491 array Methods 0.000 description 1
- 230000000747 cardiac effect Effects 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 239000010408 film Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000002608 intravascular ultrasound Methods 0.000 description 1
- 230000005865 ionizing radiation Effects 0.000 description 1
- 238000011031 large-scale manufacturing process Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000004377 microelectronic Methods 0.000 description 1
- 230000008707 rearrangement Effects 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 230000026683 transduction Effects 0.000 description 1
- 238000010361 transduction Methods 0.000 description 1
Classifications
-
- 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
Definitions
- the present application relates to the technical field of ultrasonic transducers, and in particular, to a microelectromechanical ultrasonic transducer and an array.
- ultrasonic technology and computer technology have been closely integrated, which has promoted the wide application of ultrasonic detection and ultrasonic echo imaging technology in medical, industrial, aerospace, automotive, and even consumer electronics.
- medical ultrasound has the unique advantages of good real-time performance, no damage, no pain, no ionizing radiation, and low cost. welcome.
- Ultrasound transducer also called ultrasound probe
- Traditional ultrasonic transducers are generally composed of piezoelectric ceramics, acoustic lenses, backings, electrodes, and metal shells.
- traditional ultrasonic transducers also need an additional acoustic matching layer, and the acoustic matching layer is used to complete the acoustic matching between human skin and piezoelectric ceramics, so that more ultrasonic energy enters the human tissue, which will As a result, the traditional ultrasonic transducer is large in size, complicated in assembly process and low in overall integration.
- the embodiments of the present application provide a microelectromechanical ultrasonic transducer and an array, which solve the problems of large volume, complex assembly process and low overall integration of the existing ultrasonic transducer.
- a microelectromechanical ultrasonic transducer comprising: a base layer, a bottom electrode, a piezoelectric layer, a top electrode and a passive layer; the bottom electrode, the piezoelectric layer, and the top electrode are sequentially stacked on the top surface of the base layer. and a passive layer; a groove-shaped vacuum chamber is opened on the top surface of the base layer, and the top of the groove-shaped vacuum chamber is in contact with the bottom electrode, and is used for the bottom electrode, the piezoelectric layer, the top electrode and the bottom electrode.
- the passive layer provides space for downward vibration; the passive layer is used for direct contact with the traditional acoustic transmission medium; the bottom electrode and the top electrode are used for connecting different electrode terminals respectively.
- the passive layer can be in direct contact with the traditional acoustic transmission medium, and no additional acoustic matching layer is required, thereby reducing the components of the microelectromechanical ultrasonic transducer and reducing the volume.
- the process consistency and integration of the present application are improved.
- the material of the passive layer is silicon nitride, and the thickness of the passive layer is 1-10 ⁇ m;
- the material of the piezoelectric layer is aluminum nitride or scandium aluminum nitride, and the piezoelectric layer is made of aluminum nitride or scandium aluminum nitride.
- the thickness of the electrical layer is 1 ⁇ 10 ⁇ m.
- the bottom electrode is metal material gold, platinum, aluminum or tin, and the thickness of the bottom electrode is 100-500 nm;
- the top electrode is metal material gold, platinum, aluminum or tin, so The thickness of the top electrode is 100-500 nm.
- the vacuum chamber has a positive cylindrical structure, and the top surface of the vacuum chamber is a square; the side length of the top surface of the vacuum chamber is 10-120 ⁇ m, and the depth of the vacuum chamber is 50 ⁇ 1000nm.
- the base layer includes a silicon substrate and an insulating layer stacked together;
- the bottom electrode is connected to the insulating layer, the insulating layer is made of silicon dioxide, and the thickness of the insulating layer is less than or equal to 5 ⁇ m;
- the thickness of the silicon substrate is less than or equal to 200 ⁇ m.
- the MEMS ultrasonic transducer further includes a metal layer and a pad
- the metal layer is arranged in the insulating layer and is used for forming electronic circuits, connecting the bottom electrode or the top electrode to the pad;
- the pad is used for connecting the positive electrode or the negative electrode to constitute the positive electrode or the negative electrode of the microelectromechanical ultrasonic transducer.
- the insulating layer is provided with electrode through holes and pad through holes;
- the pads include a top-surface pad and a bottom-surface pad
- a conductive connector is arranged in the electrode through hole for connecting the bottom electrode or the top electrode on the metal layer;
- a conductive connector is provided in the pad through hole for connecting the top pad to the bottom pad;
- the bottom surface of the silicon substrate may be provided with electronic circuits for moving and rearranging the position of the bottom surface pads.
- the diameter of the electrode through hole is less than or equal to 1 ⁇ m; the diameter of the pad through hole is less than or equal to 80 ⁇ m.
- the piezoelectric layer is made by a piezoelectric film process
- the MEMS ultrasonic transducer is made by a piezoelectric MEMS ultrasonic transducer manufacturing process.
- a microelectromechanical ultrasonic transducer array comprising a plurality of the microelectromechanical ultrasonic transducers, and the bottom electrodes of the plurality of the microelectromechanical ultrasonic transducers are connected together in parallel;
- the bottom electrode of the MEMS ultrasonic transducer and the top electrode of the MEMS ultrasonic transducer are respectively connected to the top pad and the bottom pad, or the bottom electrode of the MEMS ultrasonic transducer. and the top electrode of the microelectromechanical ultrasonic transducer is respectively connected to the bottom pad and the top pad;
- An isolator the isolator is arranged between the adjacent two groups of the MEMS ultrasonic transducers, and is used to isolate the acoustic signal crosstalk between the adjacent two groups of the MEMS ultrasonic transducers.
- the beneficial effects of the present application are as follows: the entire application is fabricated by the piezoelectric micro-electromechanical ultrasonic transducer manufacturing process, so that the present application has a small volume, higher process consistency and integration, and is more suitable for application in intravascular ultrasound, cardiac Intracavity ultrasound and other medical ultrasound imaging fields; in addition, the passive layer of the present application can be in direct contact with the traditional acoustic transmission medium, and no additional acoustic matching layer is required, thereby reducing the components of the MEMS ultrasonic transducer and reducing the volume. In addition, the passive layer will vibrate together with the piezoelectric layer, and will not affect the vibration frequency of the piezoelectric layer, and thus will not affect the ultrasonic transduction performance of the present application.
- FIG. 1 is a schematic cross-sectional structure diagram of a microelectromechanical ultrasonic transducer provided by an embodiment of the present application.
- FIG. 2 is a schematic cross-sectional structural diagram of a microelectromechanical ultrasonic transducer array provided in an embodiment of the present application.
- Reference numerals 10, silicon substrate; 20, insulating layer; 30, bottom electrode; 31, metal layer; 40, piezoelectric layer; 50, top electrode; 60, passive layer; 70, vacuum chamber; 80, pad; 35, electrode perforation; 81, pad perforation; 90, isolator.
- the terms “installation” and “connection” should be understood in a broad sense, for example, it may be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection, an electrical connection or can communicate with each other; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal communication between the two elements or the interaction relationship between the two elements.
- installation and “connection” should be understood in a broad sense, for example, it may be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection, an electrical connection or can communicate with each other; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal communication between the two elements or the interaction relationship between the two elements.
- the embodiments of the present application provide a microelectromechanical ultrasonic transducer and an array, which solve the problems of large volume, complex assembly process and low overall integration of the existing ultrasonic transducer.
- FIG. 1 is a schematic cross-sectional structure diagram of a microelectromechanical ultrasonic transducer provided by an embodiment of the present application.
- the microelectromechanical ultrasonic transducer provided by the embodiment of the present application includes a base layer, a bottom electrode 30, a piezoelectric layer 40, a top electrode 50 and a passive layer 60;
- the electrical layer 40, the top electrode 50 and the passive layer 60; the bottom electrode 30 and the top electrode 50 are used to connect different electrode terminals respectively;
- the top surface of the base layer is provided with a slot-shaped vacuum chamber 70, and the top of the slot-shaped vacuum chamber 70 is connected to the bottom electrode 30 contacts for providing space for the bottom electrode 30, the piezoelectric layer 40, the top electrode 50 and the passive layer 60 to vibrate downward;
- the passive layer 60 is for direct contact with the traditional acoustic transmission medium.
- the passive layer 60 can be in direct contact with the traditional acoustic transmission medium, and no additional acoustic matching layer is required, thereby reducing the components of the microelectromechanical ultrasonic transducer and reducing the volume , thereby improving the process consistency and integration of the present application.
- the bottom electrode 30 and the top electrode 50 are respectively connected to different electrodes, and the conversion of mechanical energy to electrical energy or electrical energy to mechanical energy is realized by utilizing the positive and inverse piezoelectric effects.
- the transducer of the present application by applying an alternating voltage on the bottom electrode 30 and the top electrode 50, the piezoelectric layer 40 is driven by the inverse piezoelectric effect and the passive layer 60 is driven to vibrate out of plane, thereby generating ultrasonic waves
- the positive piezoelectric effect is used to convert the vibration of the piezoelectric layer 40 and the passive layer 60 caused by external ultrasonic excitation into electrical signal output; It will drive the passive layer 60 to vibrate together, and the passive layer 60 can directly contact the traditional sound transmission medium (air, liquid), so that the acoustic impedance of the MEMS ultrasonic transducer matches the traditional sound transmission medium (air, liquid), and the vibration efficiency is obtained.
- the slot-shaped vacuum cavity 70 can provide a vibration space for the vibration of the piezoelectric layer 40 and the passive layer 60 , so that the base layer will not hinder the vibration of the piezoelectric layer 40 and the passive layer 60 , which is beneficial to increase the vibration frequency.
- the structural parameters of each component are as follows: the material of the passive layer 60 is silicon nitride, and the thickness of the passive layer 60 is 1-10 ⁇ m; the material of the piezoelectric layer 40 is aluminum nitride or scandium aluminum nitride, and the pressure The thickness of the electrical layer 40 is 1-10 ⁇ m; the bottom electrode 30 is made of gold, platinum, aluminum or tin, and the thickness of the bottom electrode 30 is 100-500nm; the top electrode 50 is made of gold, platinum, aluminum or tin, and the top electrode 50 is 100 thick ⁇ 500nm; the vacuum chamber 70 is a positive cylinder structure, and the top surface of the vacuum chamber 70 is a square; the side length of the top surface of the vacuum chamber 70 is 10 ⁇ 120 ⁇ m, the depth of vacuum chamber 70 is 50 ⁇ 1000nm.
- the material of the passive layer 60 can directly contact air and liquid, so that the application can be coupled with air and liquid without setting an acoustic matching layer.
- Ultrasound (ICE) and other medical cavity imaging technology fields are very advantageous.
- the passive layer 60 directly vibrates to generate ultrasonic waves or converts vibrations directly caused by external ultrasonic excitation into electrical signals. Without the obstruction of the acoustic matching layer, the sound production efficiency can be improved. .
- the materials for the piezoelectric layer 40 and the passive layer 60 in the present application can make the thickness of the transducer diaphragm smaller than that of the traditional piezoelectric ceramics. Since the diaphragm size is smaller, the resonant frequency of the diaphragm is smaller. The higher the vibration frequency, the higher the vibration frequency of the application.
- the thicknesses of the passive layer 60, the piezoelectric layer 40, the bottom electrode 30 and the top electrode 50 of the present application are all set to be relatively small, which can effectively reduce the volume of the transducer and increase the resonant frequency of the transducer; the vacuum of the present application
- the cavity 70 can provide a vibration space for the vibration of the piezoelectric layer 40 and the passive layer 60, and the base layer will not hinder the vibration of the piezoelectric layer 40 and the passive layer 60, which is beneficial to increase the vibration frequency.
- the area of the bottom electrode 30 It is larger than the cavity opening area of the vacuum cavity 70 , so that the vacuum environment can be maintained in the vacuum cavity 70 , and the vibration of the piezoelectric layer 40 and the passive layer 60 can have the largest vibration space.
- the vacuum chamber 70 may be set by an etching process.
- the base layer includes a silicon substrate 10 and an insulating layer 20 stacked together; the bottom electrode 30 is connected to the insulating layer 20, the insulating layer 20 is made of silicon dioxide, and the thickness of the insulating layer 20 is less than or equal to 5 ⁇ m; The thickness of the substrate 10 is less than or equal to 200 ⁇ m.
- the MEMS ultrasonic transducer further includes a metal layer 31 and a pad 80 ; the metal layer 31 is provided in the insulating layer 20 for forming an electronic circuit, connecting the bottom electrode 30 or the top electrode 50 to the pad 80 , the pad 80 is used for connecting the positive electrode or the negative electrode to constitute the positive electrode or the negative electrode of the microelectromechanical ultrasonic transducer.
- the bottom electrode 30 or the top electrode 50 is connected to the pad 80 through the metal layer 31, where the pad 80 is a metal conductive pad 80, and the bottom electrode 30 and the top electrode 30 are connected to the pad 80 by energizing the pad 80.
- the electrode 50 is energized, and the wiring is simple. Disposing the metal layer 31 in the insulating layer 20 can make the metal layer 31 and the insulating layer 20 share a part of the space, reducing the occupied volume, and the insulating layer 20 wrapping the metal layer 31 can also avoid metal layers. The current passing through layer 31 leaks.
- the insulating layer 20 is provided with an electrode through hole 35 and a pad through hole 81 ;
- the pad 80 includes a top surface pad and a bottom surface pad;
- the electrode through hole 35 is provided with a conductive connector for connecting the bottom electrode 30 Or the top electrode 50 is connected on the metal layer 31;
- a conductive connector is provided in the pad through hole 81 for connecting the top pad to the bottom pad;
- the bottom surface of the silicon substrate 10 can be provided with electronic circuits for movement and rearrangement The location of the underside pad.
- the conductive connectors in the electrode through holes 35 may be the same metal material as the metal layer 31 or other conductive wires; the conductive connectors in the pad through holes 81 may be made of the same material as the pads 80 .
- the above-mentioned pads 80 may include a top pad and a bottom pad, the top pad and the bottom pad are connected together, the top pad is set as a window structure, and the bottom pad is set at the bottom of the silicon substrate 10, through the bottom pad and the top pad.
- the pads can be connected to electrodes to supply power to the top electrode 50 and the bottom electrode 30 , which can be selected according to actual installation requirements.
- the diameter of the electrode through hole 35 is less than or equal to 1 ⁇ m; the diameter of the pad through hole 81 is less than or equal to 80 ⁇ m.
- the piezoelectric layer 40 of the present application is manufactured by using a piezoelectric thin film process, and the MEMS ultrasonic transducer is manufactured by using a piezoelectric microelectromechanical ultrasonic transducer manufacturing process.
- the ultrasonic transducer can be freed from the shackles of traditional piezoelectric ceramic materials, and can achieve high consistency, high integration, large-scale and low-cost manufacturing with the help of microelectronics technology.
- the piezoelectric microelectromechanical ultrasonic transducer manufacturing process can be better compatible with the CMOS large-scale manufacturing process, enabling the ultrasonic transducer and the analog front-end transceiver chip to be integrated on a single chip.
- the piezoelectric microelectromechanical ultrasonic transducer The transducer manufacturing process supports the array fabrication of ultrasonic transducers. The dimensional accuracy of a single ultrasonic transducer is controllable and the consistency is high, which reduces the complexity of later imaging algorithms.
- FIG. 2 is a schematic cross-sectional structural diagram of a microelectromechanical ultrasonic transducer array provided in an embodiment of the present application.
- a microelectromechanical ultrasonic transducer array including: a plurality of the above-mentioned microelectromechanical ultrasonic transducers, the bottom electrodes of the plurality of microelectromechanical ultrasonic transducers are connected together in parallel; The bottom electrode of the transducer and the top electrode of the MEMS ultrasonic transducer are respectively connected to the top pad and the bottom pad, or the bottom electrode 30 of the MEMS ultrasonic transducer and the top electrode 50 of the MEMS ultrasonic transducer are respectively connected.
- an isolator Connect the bottom pad and the top pad; an isolator, the isolator is arranged between the adjacent two groups of MEMS ultrasonic transducers, and is used to isolate the acoustic signal crosstalk between the adjacent two groups of MEMS ultrasonic transducers .
- a base layer with a larger area can be set, and then a number of slot-shaped vacuum cavities 70 are set on the base layer, and then the bottom electrode 30, the piezoelectric layer 40, the bottom electrode 30, the piezoelectric layer 40, the The top electrode 50 and the passive layer 60 can connect several ultrasonic transducers as a whole.
- the bottom electrodes 30 of several ultrasonic transducers can also be connected in series, and then pass A general pad 80 is energized, which simplifies the structure of the ultrasonic transducer array.
- Disposing an isolator between the adjacent two groups of ultrasonic transducers can isolate the acoustic signal crosstalk between the adjacent two groups of ultrasonic transducers;
- the passive layer 60 between the transducers is arranged upward and downward, and the bottom of the groove is the upper surface of the base layer.
Abstract
本申请提供了一种微机电超声波换能器及阵列，微机电超声波换能器包括：基底层、底电极（30）、压电层（40）、顶电极（50）和被动层（60）；基底层顶面依次堆叠底电极（30）、压电层（40）、顶电极（50）和被动层（60）；底电极（30）和顶电极（50）用于分别连接不同的电极接线端；基底层顶面开设有槽形真空腔（70），槽形真空腔（70）顶端与底电极（30）接触，用于为底电极（30）、压电层（40）、顶电极（50）和被动层（60）向下振动提供空间；被动层（60）用于与传统声传递介质直接接触。本申请解决了现有的超声波换能器体积大，组装工艺复杂，整体集成度低的问题。
Description
本申请要求于2021年02月09日在中国专利局提交的、申请号为202110183162.3的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
本申请涉及超声波换能器技术领域，特别涉及一种微机电超声波换能器及阵列。
随着科学技术的飞速发展, 超声技术与计算机技术得到紧密结合，推动了超声探测、超声回波成像技术在医疗、工业、航天、汽车，甚至消费电子等领域的广泛应用。尤其在医学超声成像领域，医学超声具有实时性好、无损伤、无痛苦、无电离辐射, 以及低成本等独特的优点，目前广泛用于临床检查和诊断, 倍受广大医务工作者和患者的欢迎。
超声波换能器（也称超声探头）是医疗超声成像设备的关键部件之一，其特性的好坏直接影响甚至会限制到整个设备的性能。传统的超声波换能器一般由压电陶瓷、声透镜、背衬、电极、金属外壳等组成，且为了解决传统超声波换能器的声阻抗与传统声传递介质（空气、水）不匹配导致发声效率较低的问题，传统超声波换能器还需要额外设置声匹配层，利用声匹配层来完成人体皮肤和压电陶瓷之间的声学匹配，使得更多的超声能量进入到人体组织，这样会导致传统的超声波换能器的体积大，组装工艺复杂，整体集成度低。
本申请实施例提供一种微机电超声波换能器及阵列，解决了现有的超声波换能器体积大，组装工艺复杂，整体集成度低的问题。
第一方面，提供了一种微机电超声波换能器，包括：基底层、底电极、压电层、顶电极和被动层；所述基底层顶面依次堆叠底电极、压电层、顶电极和被动层；所述基底层顶面开设有槽形真空腔，所述槽形真空腔顶端与所述底电极接触，用于为所述底电极、所述压电层、所述顶电极和所述被动层向下振动提供空间；所述被动层用于与传统声传递介质直接接触；所述底电极和所述顶电极用于分别连接不同的电极接线端。
根据本申请实施例提供的微机电超声波换能器，被动层可以与传统声传递介质直接接触，无需再额外设置声匹配层，进而减少了微机电超声波换能器的组成部件，缩小了体积，从而提升本申请工艺一致性和集成度。
在一种可能的设计中，所述被动层的材料为氮化硅，所述被动层的厚度为1 ~ 10µm；所述压电层的材料为氮化铝或者氮化钪铝，所述压电层的厚度为1~10µm。
在一种可能的设计中，所述底电极为金属材料金、铂、铝或锡，所述底电极的厚度为100 ~500nm；所述顶电极为金属材料金、铂、铝或锡，所述顶电极的厚度为100 ~500nm。
在一种可能的设计中，所述真空腔为正柱体结构，且所述真空腔的顶端面为正方形；所述真空腔顶端面的边长为10 ~ 120µm，所述真空腔的深度为50 ~1000nm。
在一种可能的设计中，所述基底层包括堆叠在一起的硅基板和绝缘层；
所述底电极连接所述绝缘层，所述绝缘层的材料为二氧化硅，所述绝缘层的厚度小于或等于5µm；
所述硅基板的厚度小于或等于200µm。
在一种可能的设计中，所述微机电超声波换能器还包括金属层和焊盘；
所述金属层设于所述绝缘层中，用于形成电子线路，连接所述底电极或者所述顶电极至所述焊盘；
所述焊盘用于连接正电极或者负电极以构成所述微机电超声波换能器的正电极或者负电极。
在一种可能的设计中，所述绝缘层中设有电极穿孔和焊盘穿孔；
所述焊盘包括顶面焊盘和底面焊盘；
所述电极穿孔中设置有导电连接体，用于将所述底电极或所述顶电极连接在所述金属层上；
所述焊盘穿孔中设置有导电连接体，用于将所述顶面焊盘连接至所述底面焊盘；
所述硅基板的底面可设置电子线路用于移动和重新布置所述底面焊盘的位置。
在一种可能的设计中，所述电极穿孔的直径小于或等于1µm；所述焊盘穿孔的直径小于或等于80µm。
在一种可能的设计中，所述压电层采用压电薄膜工艺制作而成，所述微机电超声波换能器采用压电式微机电超声波换能器制造工艺制作而成。
第二方面，提供了一种微机电超声波换能器阵列，包括若干个所述微机电超声波换能器，若干个所述微机电超声波换能器的底电极并联连接在一起；
所述微机电超声波换能器的底电极和所述微机电超声波换能器的顶电极分别连接所述顶面焊盘和所述底面焊盘，或者所述微机电超声波换能器的底电极和所述微机电超声波换能器的顶电极分别连接所述底面焊盘和所述顶面焊盘；
隔离器，所述隔离器设于相邻的两组所述微机电超声波换能器之间，用于隔离相邻两组所述微机电超声波换能器之间的声学信号串扰。
本申请的有益效果为：本申请整体采用压电式微机电超声波换能器制造工艺制作而成，使得本申请的体积微小，工艺一致性和集成度更高，更加适合应用在血管内超声、心腔内超声等医学超声成像领域；此外，本申请的被动层可以与传统声传递介质直接接触，无需再额外设置声匹配层，进而减少了微机电超声波换能器的组成部件，缩小了体积，而且被动层会与压电层一起振动，不会影响压电层的振动频率，进而不会影响本申请的超声波换能性能。
图1是本申请实施例提供的微机电超声波换能器的剖面结构示意图。
图2是本申请实施例提供的微机电超声波换能器阵列的剖面结构示意图。
附图标记：10、硅基板；20、绝缘层；30、底电极；31、金属层；40、压电层；50、顶电极；60、被动层；70、真空腔；80、焊盘；35、电极穿孔；81、焊盘穿孔；90、隔离器。
下面详细描述本申请的实施方式，所述实施方式的示例在附图中示出，其中自始至终相同或类似的标号表示相同或类似的元件或具有相同或类似功能的元件。下面通过参考附图描述的实施方式是示例性的，仅用于解释本申请，而不能理解为对本申请的限制。
在本申请的描述中，需要理解的是，术语“第一”、“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括一个或者更多个所述特征。在本申请的描述中，“多个”的含义是两个或两个以上，除非另有明确具体的限定。
在本申请的描述中，需要说明的是，除非另有明确的规定和限定，术语“安装”、“连接”应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接；可以是机械连接，也可以是电连接或可以相互通讯；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通或两个元件的相互作用关系。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请中的具体含义。
还需说明的是，本申请实施例中以同一附图标记表示同一组成部分或同一零部件，对于本申请实施例中相同的零部件，图中可能仅以其中一个零件或部件为例标注了附图标记，应理解的是，对于其他相同的零件或部件，附图标记同样适用。
本申请实施例提供一种微机电超声波换能器及阵列，解决了现有的超声波换能器体积大，组装工艺复杂，整体集成度低的问题。
图1是本申请实施例提供的微机电超声波换能器的剖面结构示意图。
如图1所示，本申请实施例提供的微机电超声波换能器包括基底层、底电极30、压电层40、顶电极50和被动层60；基底层顶面依次堆叠底电极30、压电层40、顶电极50和被动层60；底电极30和顶电极50用于分别连接不同的电极接线端；基底层顶面开设有槽形真空腔70，槽形真空腔70顶端与底电极30接触，用于为底电极30、压电层40、顶电极50和被动层60向下振动提供空间；被动层60用于与传统声传递介质直接接触。
根据本申请实施例提供的微机电超声波换能器，被动层60可以与传统声传递介质直接接触，无需再额外设置声匹配层，进而减少了微机电超声波换能器的组成部件，缩小了体积，从而提升本申请工艺一致性和集成度。
本申请中，底电极30和顶电极50分别连接不同的电极，利用正、逆压电效应实现机械能到电能或电能到机械能的转换。当本申请的换能器作为发射端时，通过在底电极30和顶电极50上施加交变电压，利用逆压电效应驱动压电层40并带动被动层60做平面外振动，从而产生超声波；当本申请的换能器作为接收端时，利用正压电效应将在外部超声波激励下引起的压电层40和被动层60的振动转化为电信号输出；由于压电层40在振动时会带动被动层60一起振动，而被动层60可以直接接触传统声传递介质（空气、液体），使得微机电超声波换能器的声阻抗与传统声传递介质（空气、液体）匹配，振动效率得到提高。槽形真空腔70可以为压电层40和被动层60的振动提供振动空间，不会使基底层阻碍压电层40和被动层60振动，有利于提升振动频率。
本申请实施例中，各部件的结构参数如下：被动层60的材料为氮化硅，被动层60的厚度为1 ~ 10µm；压电层40的材料为氮化铝或者氮化钪铝，压电层40的厚度为1~10µm；底电极30为金属材料金、铂、铝或锡，底电极30的厚度为100 ~500nm；顶电极50为金属材料金、铂、铝或锡，顶电极50的厚度为100
~500nm；真空腔70为正柱体结构，且真空腔70的顶端面为正方形；真空腔70顶端面的边长为10
~ 120µm，真空腔70的深度为50
~1000nm。
通过以上设置，被动层60的材料可以直接接触空气和液体，使得本申请无需设置声匹配层也能与空气和液体发生耦合，这对于将本申请应用在血管内超声（IVUS）、心腔内超声（ICE）等医用腔体影像技术领域来说是十分有利的，被动层60直接振动产生超声波或者将直接被外部超声波激励引起的振动转换为电信号，没有声匹配层的阻挡可以提升发声效率。
本申请中压电层40和被动层60的制作材料可以使换能器振膜的制作厚度比起传统的压电陶瓷的厚度来说变得很小，由于振膜尺寸越小，其谐振频率越高，因此本申请的振动频率得到了提升。
本申请的被动层60、压电层40、底电极30和顶电极50的厚度均设置为比较小，这样可以有效的缩小换能器的体积，提升换能器的谐振频率；本申请的真空腔70可以为压电层40和被动层60的振动提供振动空间，不会使基底层阻碍压电层40和被动层60振动，有利于提升振动频率，需要说明的是，底电极30的面积大于真空腔70的腔口面积，这样既能保证真空腔70内维持真空环境，也能使压电层40和被动层60的振动有最大的振动空间。真空腔70可以采用刻蚀工艺设置。
如图1所示，基底层包括堆叠在一起的硅基板10和绝缘层20；底电极30连接绝缘层20，绝缘层20的材料为二氧化硅，绝缘层20的厚度小于或等于5µm；硅基板10的厚度小于或等于200µm。通过以上设置，绝缘层20和硅基板10的厚度都较小，即基底层的厚度较小，有效的缩小了换能器的体积。
如图1所示，微机电超声波换能器还包括金属层31和焊盘80；金属层31设于绝缘层20中，用于形成电子线路，连接底电极30或者顶电极50至焊盘80，焊盘80用于连接正电极或者负电极以构成所述微机电超声波换能器的正电极或者负电极。
通过以上设置，将底电极30或者顶电极50通过金属层31与焊盘80连接在一起，这里的焊盘80是金属导电焊盘80，给焊盘80通电就实现了给底电极30和顶电极50通电，接线简单，将金属层31设于绝缘层20中可以使金属层31与绝缘层20共用一部分空间，缩小占用的体积，而且绝缘层20包裹金属层31也能很好的避免金属层31上通过的电流泄露。
如图1所示，绝缘层20中设有电极穿孔35和焊盘穿孔81；焊盘80包括顶面焊盘和底面焊盘；电极穿孔35中设置有导电连接体，用于将底电极30或顶电极50连接在金属层31上；焊盘穿孔81中设置有导电连接体，用于将顶面焊盘连接至底面焊盘；硅基板10的底面可设置电子线路用于移动和重新布置底面焊盘的位置。
以上设置中，电极穿孔35中的导电连接体可以是与金属层31材料相同的金属材料，也可以是其他导电线；焊盘穿孔81中设置的导电连接体可以为与焊盘80相同材料的金属。上述焊盘80可以包括顶部焊盘和底部焊盘，顶部焊盘和底部焊盘连接在一起，顶部焊盘设置为开窗结构，底部焊盘设于硅基板10底部，通过底部焊盘和顶部焊盘都可以连接电极实现对顶电极50和底电极30的供电，具体的可以根据实际的安装需求来选择。
可选的，电极穿孔35的直径小于或等于1µm；焊盘穿孔81的直径小于或等于80µm。
本申请的压电层40采用压电薄膜工艺制作而成，微机电超声波换能器采用压电式微机电超声波换能器制造工艺制作而成。通过以上设置，能够让超声波换能器摆脱传统压电陶瓷材料的束缚，借助微电子技术实现高一致性、高集成度、大规模和低成本制造。采用压电式微机电超声波换能器制造工艺，能够较好兼容CMOS大规模制造工艺制程，能够使超声波换能器与模拟前端收发器芯片集成在一个单片上，另外，压电式微机电超声波换能器制造工艺制程支持超声波换能器阵列化制作，单个超声波换能器尺寸精度可控、一致性高，降低了后期成像算法的复杂性。
图2是本申请实施例提供的微机电超声波换能器阵列的剖面结构示意图。
如图2所示，提供了一种微机电超声波换能器阵列，包括：若干个上述的微机电超声波换能器，若干个微机电超声波换能器的底电极并联连接在一起；微机电超声波换能器的底电极和微机电超声波换能器的顶电极分别连接顶面焊盘和底面焊盘，或者微机电超声波换能器的底电极30和微机电超声波换能器的顶电极50分别连接底面焊盘和顶面焊盘；隔离器，隔离器设于相邻的两组微机电超声波换能器之间，用于隔离相邻两组微机电超声波换能器之间的声学信号串扰。
以上设置中，应用微机电超声波换能器制作超声波换能器阵列时，需要若干个微机电超声波换能器，将若干个微机电超声波换能器按照线状、环状、饼状或者矩阵状的阵列排列，然后将所有微机电超声波换能器的底电极30并联连接在一起用于连接负电极，所有微机电超声波换能器的顶电极50分别与正电极串联，这样可以按照使用要求选择符合使用要求的超声波换能器，将超声波换能器阵列变换成多种不同的阵列单元来适应不同的使用要求。
制作超声波换能器阵列时可以设置一个面积较大的基底层，然后在基底层上设置若干个槽形真空腔70，再在槽形真空腔70顶端依次堆叠底电极30、压电层40、顶电极50和被动层60，这样可以将若干个超声波换能器连接成一个整体，当然，对于底电极30的供电也可以将若干个超声波换能器的底电极30串联连接在一起，然后通过一个总的焊盘80进行通电，这样可以简化超声波换能器阵列的结构。
在相邻的两组超声波换能器之间设置隔离器可以隔离相邻两组超声波换能器之间的声学信号串扰；隔离器设置为沟槽结构，该沟槽为从相邻两组超声波换能器之间的被动层60上向下设置，沟槽的槽底为基底层的上表面。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。
Claims (10)
- 一种微机电超声波换能器，其特征在于，包括：基底层、底电极（30）、压电层（40）、顶电极（50）和被动层（60）；所述基底层顶面依次堆叠所述底电极（30）、所述压电层（40）、所述顶电极（50）和所述被动层（60）；所述底电极（30）和所述顶电极（50）用于分别连接不同的电极接线端；所述基底层顶面开设有槽形真空腔（70），所述槽形真空腔（70）顶端与所述底电极（30）接触，用于为所述底电极（30）、所述压电层（40）、所述顶电极（50）和所述被动层（60）向下振动提供空间；所述被动层（60）用于与传统声传递介质直接接触。
- 根据权利要求1所述的微机电超声波换能器，其特征在于，所述被动层（60）的材料为氮化硅，所述被动层（60）的厚度为1 ~ 10µm；所述压电层（40）的材料为氮化铝或者氮化钪铝，所述压电层（40）的厚度为1~10µm。
- 根据权利要求1所述的微机电超声波换能器，其特征在于，所述底电极（30）为金属材料金、铂、铝或锡，所述底电极（30）的厚度为100 ~500nm；所述顶电极（50）为金属材料金、铂、铝或锡，所述顶电极（50）的厚度为100 ~500nm。
- 根据权利要求1所述的微机电超声波换能器，其特征在于，所述真空腔（70）为正柱体结构，且所述真空腔（70）的顶端面为正方形；所述真空腔（70）顶端面的边长为10 ~ 120µm，所述真空腔（70）的深度为50 ~1000nm。
- 根据权利要求1所述的微机电超声波换能器，其特征在于，所述基底层包括堆叠在一起的硅基板（10）和绝缘层（20）；所述底电极（30）连接所述绝缘层（20），所述绝缘层（20）的材料为二氧化硅，所述绝缘层（20）的厚度小于或等于5µm；所述硅基板（10）的厚度小于或等于200µm。
- 根据权利要求5所述的微机电超声波换能器，其特征在于，所述微机电超声波换能器还包括金属层（31）和焊盘（80）；所述金属层（31）设于所述绝缘层（20）中，用于形成电子线路，连接所述底电极（30）或者所述顶电极（50）至所述焊盘（80）；所述焊盘（80）用于连接正电极或者负电极以构成所述微机电超声波换能器的正电极或者负电极。
- 根据权利要求6所述的微机电超声波换能器，其特征在于，所述绝缘层（20）中设有电极穿孔（35）和焊盘穿孔（81）；所述焊盘（80）包括顶面焊盘和底面焊盘；所述电极穿孔（35）中设置有导电连接体，用于将所述底电极（30）或所述顶电极（50）连接在所述金属层（31）上；所述焊盘穿孔（81）中设置有导电连接体，用于将所述顶面焊盘连接至所述底面焊盘；所述硅基板（10）的底面可设置电子线路用于移动和重新布置所述底面焊盘的位置。
- 根据权利要求7所述的微机电超声波换能器，其特征在于，所述电极穿孔（35）的直径小于或等于1µm；所述焊盘穿孔（81）的直径小于或等于80µm。
- 根据权利要求1-8任一项所述的微机电超声波换能器，其特征在于，所述压电层（40）采用压电薄膜工艺制作而成，所述微机电超声波换能器采用压电式微机电超声波换能器制造工艺制作而成。
- 一种微机电超声波换能器阵列，其特征在于，包括：若干个如权利要求7-9任一项所述的微机电超声波换能器，若干个所述微机电超声波换能器的底电极（30）并联连接在一起；所述微机电超声波换能器的底电极（30）和所述微机电超声波换能器的顶电极（50）分别连接所述顶面焊盘和所述底面焊盘，或者所述微机电超声波换能器的底电极（30）和所述微机电超声波换能器的顶电极（50）分别连接所述底面焊盘和所述顶面焊盘；隔离器（90），所述隔离器（90）设于相邻的两组所述微机电超声波换能器之间，用于隔离相邻两组所述微机电超声波换能器之间的声学信号串扰。
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110183162.3A CN113145431A (zh) | 2021-02-09 | 2021-02-09 | 一种微机电超声波换能器及阵列 |
| CN202110183162.3 | 2021-02-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2022170805A1 true WO2022170805A1 (zh) | 2022-08-18 |
Family
ID=76883122
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/CN2021/131525 WO2022170805A1 (zh) | 2021-02-09 | 2021-11-18 | 一种微机电超声波换能器及阵列 |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN113145431A (zh) |
| WO (1) | WO2022170805A1 (zh) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113145431A (zh) * | 2021-02-09 | 2021-07-23 | 深圳市赛禾医疗技术有限公司 | 一种微机电超声波换能器及阵列 |
| CN114007175B (zh) * | 2021-10-19 | 2022-08-23 | 上海交通大学 | 超声换能器阵列及其形成方法 |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106211005A (zh) * | 2014-08-08 | 2016-12-07 | 佳能株式会社 | 具有与贯通线连接的电极的设备及其制造方法 |
| CN106660074A (zh) * | 2014-07-08 | 2017-05-10 | 高通股份有限公司 | 压电超声换能器及工艺 |
| CN106951887A (zh) * | 2017-04-25 | 2017-07-14 | 太原科技大学 | 用于识别的微电容超声波换能器线性阵列装置 |
| US20170326594A1 (en) * | 2016-05-10 | 2017-11-16 | Invensense, Inc. | Ultrasonic transducer with a non-uniform membrane |
| CN108698084A (zh) * | 2016-02-29 | 2018-10-23 | 高通股份有限公司 | 压电微机械超声换能器和换能器阵列 |
| CN109225789A (zh) * | 2018-09-06 | 2019-01-18 | 姬俊鹏 | 一种组合式变刚度薄膜pMUTs及其制备方法 |
| CN111817682A (zh) * | 2020-07-27 | 2020-10-23 | 松山湖材料实验室 | 一种薄膜体声波谐振器及其制备方法 |
| CN113145431A (zh) * | 2021-02-09 | 2021-07-23 | 深圳市赛禾医疗技术有限公司 | 一种微机电超声波换能器及阵列 |
| CN214718133U (zh) * | 2021-02-09 | 2021-11-16 | 深圳市赛禾医疗技术有限公司 | 一种微机电超声波换能器及阵列 |
-
2021
- 2021-02-09 CN CN202110183162.3A patent/CN113145431A/zh active Pending
- 2021-11-18 WO PCT/CN2021/131525 patent/WO2022170805A1/zh active Application Filing
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106660074A (zh) * | 2014-07-08 | 2017-05-10 | 高通股份有限公司 | 压电超声换能器及工艺 |
| CN106211005A (zh) * | 2014-08-08 | 2016-12-07 | 佳能株式会社 | 具有与贯通线连接的电极的设备及其制造方法 |
| CN108698084A (zh) * | 2016-02-29 | 2018-10-23 | 高通股份有限公司 | 压电微机械超声换能器和换能器阵列 |
| US20170326594A1 (en) * | 2016-05-10 | 2017-11-16 | Invensense, Inc. | Ultrasonic transducer with a non-uniform membrane |
| CN106951887A (zh) * | 2017-04-25 | 2017-07-14 | 太原科技大学 | 用于识别的微电容超声波换能器线性阵列装置 |
| CN109225789A (zh) * | 2018-09-06 | 2019-01-18 | 姬俊鹏 | 一种组合式变刚度薄膜pMUTs及其制备方法 |
| CN111817682A (zh) * | 2020-07-27 | 2020-10-23 | 松山湖材料实验室 | 一种薄膜体声波谐振器及其制备方法 |
| CN113145431A (zh) * | 2021-02-09 | 2021-07-23 | 深圳市赛禾医疗技术有限公司 | 一种微机电超声波换能器及阵列 |
| CN214718133U (zh) * | 2021-02-09 | 2021-11-16 | 深圳市赛禾医疗技术有限公司 | 一种微机电超声波换能器及阵列 |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113145431A (zh) | 2021-07-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110545731B (zh) | 具有压电传感器的成像装置 | |
| US7880565B2 (en) | Micro-electro-mechanical transducer having a surface plate | |
| AU2006218723B2 (en) | Piezoelectric micromachined ultrasonic transducer with air-backed cavities | |
| CN106198724B (zh) | 一种多稳态超声检测传感器 | |
| WO2022170805A1 (zh) | 一种微机电超声波换能器及阵列 | |
| CN110052391B (zh) | 双谐振模式耦合的微机械压电超声波换能器 | |
| JP4049743B2 (ja) | 音響エネルギーの横方向の伝搬を制限する超小型超音波トランスデューサ（ｍｕｔ）基板 | |
| CN111182429B (zh) | 高填充率mems换能器 | |
| KR101761819B1 (ko) | 초음파 변환기 및 그 제조 방법 | |
| CN214718133U (zh) | 一种微机电超声波换能器及阵列 | |
| CN110560351B (zh) | 基于Helmholtz共振腔的可调频声波接收装置 | |
| CN112871612A (zh) | 具有多压电层的压电微机械超声换能器 | |
| JP6390428B2 (ja) | 超音波振動子セル、超音波プローブ、及び超音波振動子セルの制御方法 | |
| CN114864806A (zh) | 具有短波导结构的超声换能器及制造方法、超声检测装置 | |
| CN105036058A (zh) | 集成化电容式微加工超声换能器及其制备方法 | |
| Mescher et al. | Novel MEMS microshell transducer arrays for high-resolution underwater acoustic imaging applications | |
| CN114130636B (zh) | 一种压电式mems超声换能器 | |
| US20230002213A1 (en) | Micro-machined ultrasound transducers with insulation layer and methods of manufacture | |
| CN111570245B (zh) | 一种具有蝶形振动薄膜的微机电压电式超声换能器 | |
| JP2007274620A (ja) | アレイ探触子、アレイ探触子デバイス、およびアレイ探触子の製造方法 | |
| Zhao et al. | Design, Fabrication, and Characterization of High-Performance PMUT Arrays Based on Potassium Sodium Niobate | |
| CN115780223A (zh) | 一种mems超声波换能器 | |
| EP4363369A1 (en) | Micro-machined ultrasound transducers with insulation layer and methods of manufacture | |
| CN117499848A (zh) | Mems压电扬声器及其制备方法 | |
| Kirkos et al. | P1-21: Novel MEMS Microshell Transducer Arrays For High-Resol ut ion U nde M ater Acoustic I magi ng Applications |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 21925452 Country of ref document: EP Kind code of ref document: A1 |
|
| NENP | Non-entry into the national phase |
Ref country code: DE |
|
| 122 | Ep: pct application non-entry in european phase |
Ref document number: 21925452 Country of ref document: EP Kind code of ref document: A1 |