MEMS ultrasonic transducer, method of manufacturing same, and electronic device including same

Abstract

The invention relates to a MEMS ultrasonic transducer, a manufacturing method of the MEMS ultrasonic transducer and electronic equipment comprising the MEMS ultrasonic transducer. The MEMS ultrasonic transducer comprises an MEMS acoustic wave device which is suitable for vibrating to generate ultrasonic waves or being excited by the ultrasonic waves to generate vibration; the packaging layer is used for packaging the MEMS acoustic wave device, so that a closed space for accommodating a vibration medium is formed between the packaging layer and the MEMS acoustic wave device, and the packaging layer is suitable for transmitting vibration of the acoustic wave device outwards or transmitting external vibration to the acoustic wave device based on the closed space.

Description

Technical Field

[0001] Embodiments of the present invention relate to the semiconductor field, and in particular, to a MEMS ultrasonic transducer, a manufacturing method thereof, and an electronic device comprising the same. Background Art

[0002] A MEMS (Micro-electro Mechanical Systems) transducer is a miniature transducer that converts electrical signals into acoustic signals. Its core components (such as actuators / drivers, diaphragms, thermoacoustic membranes, etc.) are manufactured on semiconductor materials using MEMS technology.

[0003] MEMS ultrasonic transducers apply AC signals to make the device film vibrate back and forth, thereby pushing the air to form ultrasonic waves. In particular, when the device operates near the resonant frequency, it can achieve greater output or receive signals. In order to avoid the impact of harsh environments on MEMS ultrasonic transducers, they usually need to be packaged during actual use. The packaging of traditional MEMS ultrasonic transducers requires reserving a sound wave propagation channel, that is, a part of the device area is still connected to the outside world through the sound wave propagation channel, which makes the MEMS ultrasonic transducer susceptible to the impact of the external environment. Summary of the invention

[0004] The present invention is proposed to alleviate or solve at least one aspect of the above-mentioned problems in the prior art.

[0005] According to one aspect of an embodiment of the present invention, a MEMS ultrasonic transducer is provided, comprising:

[0006] substrate;

[0007] A MEMS acoustic wave device adapted to vibrate to generate ultrasonic waves or to be excited by ultrasonic waves to vibrate; and

[0008] A packaging layer is used to package the MEMS acoustic wave device so as to form a closed space for accommodating a vibration medium between the packaging layer and the MEMS acoustic wave device, wherein:

[0009] Based on the closed space, the packaging layer is suitable for transmitting the vibration of the acoustic wave device to the outside or transmitting external vibration to the acoustic wave device.

[0010] According to one aspect of an embodiment of the present invention, a MEMS ultrasonic transducer is provided, comprising:

[0011] MEMS acoustic wave devices;

[0012] A packaging layer, used for packaging MEMS acoustic wave devices;

[0013] A sealed vibration medium layer is arranged between the packaging layer and the MEMS acoustic wave device, wherein: the acoustic wave is transmitted outwardly through the path of MEMS acoustic wave device-vibration medium layer-packaging layer, or is transmitted inwardly through packaging layer-vibration medium layer-MEMS acoustic wave device.

[0014] According to one aspect of an embodiment of the present invention, a method for manufacturing a MEMS ultrasonic transducer is provided, comprising the steps of:

[0015] Providing a MEMS acoustic wave device, the MEMS acoustic wave device is suitable for vibrating to generate ultrasonic waves or being excited by ultrasonic waves to generate vibrations;

[0016] The MEMS acoustic wave device is encapsulated by the encapsulation layer, so that a closed space for accommodating the vibration medium is formed between the encapsulation layer and the MEMS acoustic wave device.

[0017] in:

[0018] Based on the closed space, the packaging layer is suitable for transmitting the vibration of the acoustic wave device to the outside or transmitting external vibration to the acoustic wave device.

[0019] An embodiment of the present invention also relates to an electronic device, comprising the above-mentioned MEMS acoustic wave device ultrasonic transducer. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The following description and accompanying drawings may better help understand these and other features and advantages of various embodiments disclosed by the present invention, in which the same reference numerals always represent the same components, wherein:

[0021] Figure 1 is a cross-sectional schematic diagram of a MEMS ultrasonic transducer according to a first embodiment of the present invention;

[0022] Figure 2 for Figure 1 Schematic diagram of the sound wave transmission process of the MEMS ultrasonic transducer;

[0023] Figure 3 This is a simulation effect diagram, which exemplarily shows the relationship between the displacement of the silicon film of the MEMS ultrasonic transducer according to an embodiment of the present invention and the thickness of the silicon film;

[0024] Figure 4 is a schematic cross-sectional view of a MEMS ultrasonic transducer according to a second embodiment of the present invention;

[0025] Figure 5 is a cross-sectional schematic diagram of a MEMS ultrasonic transducer according to a third embodiment of the present invention;

[0026] Figure 6is a schematic cross-sectional view of a MEMS ultrasonic transducer according to a fourth embodiment of the present invention;

[0027] Figure 7 is a schematic cross-sectional view of a MEMS ultrasonic transducer according to a fifth embodiment of the present invention;

[0028] Figure 8 is a structural schematic diagram of a bimorph structure according to an embodiment of the present invention;

[0029] Fig. 9 A schematic diagram of the structure of a back-engraved MEMS according to an embodiment of the present invention;

[0030] Fig.10 is a flow chart of a method for manufacturing a MEMS ultrasonic transducer according to a first embodiment of the present invention;

[0031] Fig.11 is a flow chart of a method for manufacturing a MEMS ultrasonic transducer according to a second embodiment of the present invention;

[0032] Fig.12 FIG. 4 is a flow chart of a method for manufacturing a MEMS ultrasonic transducer according to a third embodiment of the present invention. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is further specifically described below through examples and in conjunction with the accompanying drawings. In the specification, the same or similar figure numbers indicate the same or similar parts. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall inventive concept of the present invention and should not be understood as a limitation of the present invention. Some embodiments of the invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0034] The packaging of traditional MEMS acoustic wave devices requires a reserved acoustic wave propagation channel, that is, a part of the device area is still connected to the outside world through the acoustic wave propagation channel, which leads to high requirements for the application environment of the MEMS ultrasonic transducer. The MEMS ultrasonic transducer in the present invention uses a packaging layer to completely wrap the MEMS acoustic wave device (that is, the acoustic wave propagation channel required for the packaging of traditional MEMS acoustic wave devices is not reserved), and the sound wave is transmitted outward through the MEMS acoustic wave device-vibration medium (such as air)-packaging layer path, or transmitted inward through the packaging layer-vibration medium (such as air)-MEMS acoustic wave device, so that the device can be protected and the external influence can be reduced while maintaining the original performance of the device in emitting sound waves to the outside world and receiving ultrasonic waves from the outside world. Correspondingly, the present invention proposes a MEMS ultrasonic transducer, including: a MEMS acoustic wave device and a packaging layer, a sealed vibration medium layer is arranged between the packaging layer and the MEMS acoustic wave device, wherein: the sound wave is transmitted outward through the MEMS acoustic wave device-vibration medium-packaging layer path, or transmitted inward through the packaging layer-vibration medium-MEMS acoustic wave device.

[0035] Referring to the accompanying drawings, the present invention proposes a MEMS ultrasonic transducer, comprising: a substrate; a MEMS acoustic wave device, which is suitable for vibrating to generate ultrasonic waves or being excited by ultrasonic waves to generate vibrations; and a packaging layer, which is used to package the MEMS acoustic wave device so as to form a closed space for accommodating a vibration medium between the packaging layer and the MEMS acoustic wave device, wherein: based on the closed space, the packaging layer is suitable for transmitting the vibration of the acoustic wave device to the outside or transmitting external vibrations to the acoustic wave device. More specifically, the MEMS acoustic wave device has a first effective vibration area, and the packaging layer has a second effective vibration area opposite to the first effective vibration area.

[0036] Figure 1 FIG. 2 is a schematic cross-sectional view of a MEMS ultrasonic transducer according to a first embodiment of the present invention. Figure 1 As shown, the MEMS ultrasonic transducer comprises a MEMS acoustic wave device 2 and a packaging film 1. The MEMS acoustic wave device 2 and the packaging film 1 are bonded via bonding layers 7 and 8.

[0037] The MEMS acoustic wave device 2 includes a bottom electrode 5, a piezoelectric layer 4 and a top electrode 3 sequentially stacked on a substrate 6. The MEMS acoustic wave device 2 is used, for example, to transmit and receive ultrasonic waves. Optionally, the resonant frequency of the MEMS acoustic wave device 2 is between 20 kHz and 50 MHz. Optionally, the MEMS acoustic wave device 2 is a piezoelectric micromechanical ultrasonic transducer (MEMS ultrasonic transducer) structure.

[0038] The packaging film 1 covers the MEMS acoustic wave device 2 from the upper side of the MEMS acoustic wave device 2. The material of the packaging film 1 is, for example, silicon. A closed cavity 19 for accommodating a vibration medium is formed between the packaging film 1 and the MEMS acoustic wave device 2. The above-mentioned vibration medium can be a gas such as air. The vibration medium in the present invention is not limited to this, and can also be other media known to those skilled in the art, such as liquids such as silicone oil. In an optional embodiment, the vibration medium is air, and the air pressure in the closed cavity 19 is not less than 100 Pa, so as to effectively transmit vibration.

[0039] like Figure 1 As shown, the substrate 6 has a cavity 29. The area where the piezoelectric layer 4 is located above the cavity 29 forms a first effective vibration area of ​​the MEMS acoustic wave device. A second effective vibration area is formed on the packaging film 1 at a position opposite to the first effective vibration area. In an optional embodiment, the effective stiffness of the second effective vibration area is not higher than 8 times the effective stiffness of the first effective vibration area. In a further embodiment, the effective stiffness of the second effective vibration area is not higher than the effective stiffness of the first effective vibration area. The packaging film 1 has a sufficiently low effective stiffness in order to effectively couple the MEMS acoustic wave device 2 and the external environment through the vibration of the packaging film 1, thereby maintaining the original performance of the MEMS acoustic wave device 2 in emitting sound waves to the outside world and receiving sound waves from the outside world.

[0040] Figure 2 for Figure 1 Schematic diagram of the sound wave transmission process of the MEMS ultrasonic transducer in FIG. 1 , which shows the sound wave transmission process when transmitting sound waves. Figure 2 As shown, when transmitting sound waves, the MEMS acoustic wave device 2 vibrates under the action of the alternating signal, pushing the vibration medium (such as air) between the MEMS acoustic wave device 2 and the packaging film 1 to move, thereby pushing the packaging film 1 to vibrate and emitting sound waves to the outside world. As can be understood by those skilled in the art, when receiving sound waves, the external sound waves act on the packaging film 1, causing the packaging film 1 to vibrate, pushing the vibration medium (such as air) between the packaging film 1 and the MEMS acoustic wave device 2 to move, thereby pushing the MEMS acoustic wave device 2 to vibrate, thereby converting the sound signal into other recognizable signal forms, such as electrical signals.

[0041] In an optional embodiment, at least one of the packaging film 1, the MEMS acoustic wave device 2 and the vibration medium (such as air) operates in a resonant state. In a further embodiment, at least two of the packaging film 1, the MEMS acoustic wave device 2 and the vibration medium (such as air) operate in a resonant state. In a further embodiment, the packaging film 1, the MEMS acoustic wave device 2 and the vibration medium (such as air) all operate in a resonant state. The above method is conducive to improving the sound wave transmission performance. When the packaging film 1 operates in a resonant state, the thickness of the packaging film 1 can be appropriately increased so that it can operate in a more severe environment without losing reliability.

[0042] Figure 3 This is a simulation effect diagram, which exemplarily shows the relationship between the displacement of the silicon film of the MEMS ultrasonic transducer according to an embodiment of the present invention and the thickness of the silicon film. Figure 3 As shown, in this example, the material of the packaging film 1 is silicon, and a MEMS acoustic wave device 2 with a certain resonant frequency can be designed. When the thickness of the packaging film 1 is about 4.5 microns, its resonant frequency is consistent with the MEMS acoustic wave device 2, and the displacement of the packaging film 1 is maximum at this time.

[0043] Figure 4 FIG. 2 is a cross-sectional schematic diagram of a MEMS ultrasonic transducer according to a second embodiment of the present invention. Figure 1 The difference between the embodiments is that the materials of the packaging films are different. Figure 1 In the embodiment of FIG. 1 , the material of the encapsulation film 1 is, for example, silicon. Figure 4 In the embodiment of the present invention, the material of the encapsulation film 12 is a silicon compound or a metal compound, such as silicon nitride, silicon oxide, aluminum nitride or aluminum oxide.

[0044] like Figure 4 As shown, a release hole 9 is provided on the packaging film 12, which can be used to release the sacrificial material during the manufacturing process. The packaging film 12 is covered with a sealing layer 13. The sealing layer 13 covers the release hole 9 to ensure the airtightness of the cavity between the packaging film 12 and the MEMS acoustic wave device 2. In an optional embodiment, the sealing layer 13 has a dense structure.

[0045] Figure 5 FIG. 4 is a cross-sectional schematic diagram of a MEMS ultrasonic transducer according to a third embodiment of the present invention. Figure 1 The difference between the embodiments is that the materials of the packaging films are different. Figure 1 In the embodiment of FIG. 1 , the material of the encapsulation film 1 is, for example, silicon. Figure 5 In the embodiment of the present invention, the material of the packaging film 14 is a polymer, such as resin.

[0046] like Figure 5As shown, an electrode pad 15 is provided on the upper surface of the piezoelectric layer 4, and a metal column 16 and a metal ball 17 are provided on the packaging film 14. The electrode pad 15, the metal column 16 and the metal ball 17 are used together for external electrical connection of the MEMS acoustic wave device. It should be pointed out that the structure of the electrode pad 15, the metal column 16 and the metal ball 17 can also be used in other embodiments.

[0047] In an optional embodiment, if Fig.10 As shown in the lowermost part, the MEMS ultrasonic transducer may include at least two MEMS acoustic wave devices, and at least two MEMS acoustic wave devices share the packaging film 1 .

[0048] Figure 6 FIG. 4 is a cross-sectional schematic diagram of a MEMS ultrasonic transducer according to a fourth embodiment of the present invention. In the aforementioned embodiments, the packaging layer above the MEMS acoustic wave device is a packaging film, and Figure 6 In the embodiment of the present invention, the packaging layer above the MEMS acoustic wave device is another MEMS acoustic wave device.

[0049] like Figure 6 As shown, the lower MEMS acoustic wave device 2 is covered from above by another MEMS acoustic wave device, and a closed cavity 19 for accommodating a vibration medium (such as air) is formed between the two MEMS acoustic wave devices 2. The advantages of this embodiment are: when the upper MEMS acoustic wave device 2 is not failed, the two MEMS acoustic wave devices 2 can be resonantly excited together, thereby achieving a higher sound pressure output or reception; when the upper MEMS acoustic wave device 2 fails, its function is similar to the packaging film in the aforementioned embodiment, but it is easier to resonate and match with the lower MEMS acoustic wave device 2, thereby achieving better acoustic performance.

[0050] MEMS acoustic wave devices as packaging layers can be stacked in multiple layers. Figure 7 As shown, three MEMS acoustic wave devices 2 are stacked in sequence, wherein the upper two MEMS acoustic wave devices 2 can function as packaging layers.

[0051] In an optional embodiment, the MEMS acoustic wave device 2 may adopt a bimorph structure. Figure 8 Such a structure is shown in which two piezoelectric layers 4 and three electrodes 3 are alternately stacked.

[0052] In an optional embodiment, the MEMS acoustic wave device 2 may be a back-engraved type MEMS acoustic wave device. Fig. 9 Such a structure is shown, in which a substrate 6 supports both ends of the MEMS acoustic wave device 2 from below, and a cavity penetrates the substrate 6 .

[0053] The invention also provides a method for manufacturing the MEMS ultrasonic transducer.

[0054] Fig.10 FIG. 1 is a flowchart of a method for manufacturing a MEMS ultrasonic transducer according to a first embodiment of the present invention, which can be used to manufacture Figure 1 MEMS ultrasonic transducer in. Fig.10 As shown, the method may include the following steps:

[0055] Step 1: Provide a SOI (Silicon-On-Insulator) wafer, wherein the SOI wafer includes a substrate 10, an insulating layer 9 and a top silicon 1 stacked in sequence.

[0056] Step 2: Etch at least two recessed areas on the surface of the top silicon 1.

[0057] Step 3: Joining the etched SIO wafer to the MEMS acoustic wave device array to form a closed space for accommodating the vibration medium based on the recessed area, wherein the MEMS acoustic wave device array includes at least two MEMS acoustic wave devices, and each MEMS acoustic wave device is located in a corresponding recessed area.

[0058] Step 4: remove the substrate 10 and the insulating layer 9 of the SIO wafer, and retain the top silicon 1.

[0059] In an optional implementation, step 3 further includes the following steps:

[0060] Step 3-1: deposit bonding layers on the SIO wafer and the MEMS acoustic wave device array respectively.

[0061] Step 3-2: Bonding the bonding layer on the SIO wafer and the bonding layer on the MEMS acoustic wave device array.

[0062] Fig.11 FIG. 1 is a flowchart of a method for manufacturing a MEMS ultrasonic transducer according to a second embodiment of the present invention, which can be used to manufacture Figure 4 MEMS ultrasonic transducer in. Fig.11 As shown, the method may include the following steps:

[0063] Step 1: depositing a sacrificial material 11 on the MEMS acoustic wave device 2. The sacrificial material 11 is, for example, phosphosilicate glass (PSG).

[0064] Step 2: depositing a packaging thin film material on the sacrificial material 11 to form a packaging thin film 12 .

[0065] Step 3: Etch the release hole 9 on the packaging film 12 and release the sacrificial material 11 to form a space for accommodating the vibration medium. The formed space can be filled with gas or liquid.

[0066] Step 4: a sealing layer 13 is provided on the packaging film 12 to seal the release hole 9 to form a closed space for accommodating the vibration medium.

[0067] Fig.12 is a flowchart of a method for manufacturing a MEMS ultrasonic transducer according to a third embodiment of the present invention, which can be used to manufacture Figure 5 MEMS ultrasonic transducer in. Fig.12 As shown, the method may include the following steps:

[0068] Step 1: providing a polymer encapsulation film 14, wherein the polymer encapsulation film 14 has a recessed area.

[0069] Step 2: Bond the polymer packaging film 14 to the MEMS acoustic wave device to form a closed space for accommodating the vibration medium based on the recessed area, wherein the MEMS acoustic wave device is located in the recessed area.

[0070] In an optional embodiment, after step 2, the following steps may also be included:

[0071] Step 3: forming external electrical connection components, including metal pillars 16 and metal balls 17, on the polymer packaging film.

[0072] An embodiment of the present invention also relates to an electronic device, comprising the above-mentioned MEMS ultrasonic transducer.

[0073] Based on the above, the present invention proposes the following technical solutions:

[0074] 1. A MEMS ultrasonic transducer, comprising:

[0075] A MEMS acoustic wave device adapted to vibrate to generate ultrasonic waves or to be excited by ultrasonic waves to vibrate; and

[0076] A packaging layer is used to package the MEMS acoustic wave device so as to form a closed space for accommodating a vibration medium between the packaging layer and the MEMS acoustic wave device, wherein:

[0077] Based on the closed space, the packaging layer is suitable for transmitting the vibration of the acoustic wave device to the outside or transmitting external vibration to the acoustic wave device.

[0078] 2. The MEMS ultrasonic transducer according to item 1, wherein:

[0079] The MEMS acoustic wave device is disposed on a substrate;

[0080] The acoustic wave device is provided with a first vibration space and a second vibration space on both sides in the thickness direction of the acoustic wave device respectively;

[0081] The first vibration space is arranged between the first side of the acoustic wave device and the substrate or in the substrate, and the second vibration space is the closed space.

[0082] 3. The MEMS ultrasonic transducer according to 2, wherein:

[0083] The packaging layer is arranged on a second side of the acoustic wave device opposite to the first side, the second vibration space is arranged between the second side of the acoustic wave device and the packaging layer, the first vibration space and the second vibration space have an overlapping area in the thickness direction of the acoustic wave device, and the first effective vibration area of ​​the acoustic wave device is arranged in the overlapping area in the thickness direction of the acoustic wave device;

[0084] The encapsulation layer is provided with a second effective vibration region opposite to the first effective vibration region.

[0085] 4. The MEMS ultrasonic transducer according to 3, wherein:

[0086] The effective stiffness of the second effective vibration area is not higher than 8 times the effective stiffness of the first effective vibration area.

[0087] 5. The MEMS ultrasonic transducer according to 4, wherein:

[0088] An effective stiffness of the second effective vibration region is not higher than an effective stiffness of the first effective vibration region.

[0089] 6. The MEMS ultrasonic transducer according to 2, wherein:

[0090] The acoustic wave device comprises a MEMS acoustic wave device.

[0091] 7. The MEMS ultrasonic transducer according to 6, wherein:

[0092] The acoustic wave device is a bi-piezoelectric chip structure.

[0093] 8. The MEMS ultrasonic transducer according to any one of 2-7, wherein:

[0094] The encapsulation layer includes an encapsulation film.

[0095] 9. The MEMS ultrasonic transducer according to 8, wherein:

[0096] The packaging film is a closed film layer.

[0097] 10. The MEMS ultrasonic transducer according to 8, wherein:

[0098] The packaging film is provided with a release hole, and the release hole is communicated with the enclosed space;

[0099] The packaging layer further includes a sealing layer covering a side of the packaging film away from the acoustic wave device so as to cover the release hole.

[0100] 11. The MEMS ultrasonic transducer according to 8, wherein:

[0101] The material of the encapsulation film is one of silicon, silicon nitride, silicon oxide, aluminum nitride or aluminum oxide, and polymer.

[0102] 12. The MEMS ultrasonic transducer according to any one of 2-7, wherein:

[0103] The acoustic wave device is a first acoustic wave device;

[0104] The packaging layer includes a second acoustic wave device, the second acoustic wave device is overlapped with the first acoustic wave device in a thickness direction of the first acoustic wave device, and the second vibration space is provided between the second acoustic wave device and the first acoustic wave device.

[0105] 13. The MEMS ultrasonic transducer according to 12, wherein:

[0106] The packaging layer also includes a third acoustic wave device, and the third acoustic wave device, the second acoustic wave device and the first acoustic wave device are stacked in the thickness direction of the first acoustic wave device, the second vibration space is arranged between the second acoustic wave device and the first acoustic wave device, and the third vibration space is arranged between the second acoustic wave device and the third acoustic wave device.

[0107] 14. The MEMS ultrasonic transducer according to 13, wherein:

[0108] The second vibration space and the third vibration space are closed spaces; or

[0109] The second vibration space is a closed space, and the third vibration space is a non-closed space.

[0110] 15. The MEMS ultrasonic transducer according to 13, wherein:

[0111] The first acoustic wave device and the second acoustic wave device are bimorph structures.

[0112] 16. The MEMS ultrasonic transducer according to any one of 2-7, wherein:

[0113] The ultrasonic transducer includes at least two acoustic wave devices, and the at least two acoustic wave devices are arranged in the same layer and share the packaging layer.

[0114] 17. The MEMS ultrasonic transducer according to item 1, wherein:

[0115] The MEMS acoustic wave device and the packaging layer have the same resonance frequency.

[0116] 18. The MEMS ultrasonic transducer according to 17, wherein:

[0117] At least one of the MEMS acoustic wave device, the vibration medium and the packaging layer operates in a resonant state.

[0118] 19. The MEMS ultrasonic transducer according to 17, wherein:

[0119] At least two of the MEMS acoustic wave device, the vibration medium and the packaging layer operate in a resonant state.

[0120] 20. The MEMS ultrasonic transducer according to item 1, wherein:

[0121] The encapsulation layer is an encapsulation film.

[0122] 21. The MEMS ultrasonic transducer according to 20, wherein:

[0123] The material of the encapsulation film is one of silicon, silicon nitride, silicon oxide, aluminum nitride or aluminum oxide, and polymer.

[0124] 22. The MEMS ultrasonic transducer according to item 1, wherein:

[0125] The MEMS acoustic wave device is a back-engraved type MEMS acoustic wave device.

[0126] 23. The MEMS ultrasonic transducer according to item 1, wherein:

[0127] The vibration medium is air, and the air pressure in the closed cavity is not less than 100 Pa; or

[0128] The vibration medium is liquid.

[0129] 24. A MEMS ultrasonic transducer, comprising:

[0130] MEMS acoustic wave devices;

[0131] A packaging layer, used for packaging MEMS acoustic wave devices;

[0132] A sealed vibration medium layer is arranged between the packaging layer and the MEMS acoustic wave device, wherein: the acoustic wave is transmitted outwardly through the path of MEMS acoustic wave device-vibration medium layer-packaging layer, or is transmitted inwardly through packaging layer-vibration medium layer-MEMS acoustic wave device.

[0133] 25. A method for manufacturing a MEMS ultrasonic transducer, comprising the steps of:

[0134] Providing a MEMS acoustic wave device, the MEMS acoustic wave device is suitable for vibrating to generate ultrasonic waves or being excited by ultrasonic waves to generate vibrations;

[0135] The MEMS acoustic wave device is encapsulated by the encapsulation layer, so that a closed space for accommodating the vibration medium is formed between the encapsulation layer and the MEMS acoustic wave device.

[0136] in:

[0137] Based on the closed space, the packaging layer is suitable for transmitting the vibration of the acoustic wave device to the outside or transmitting external vibration to the acoustic wave device.

[0138] 26. The method according to 25, comprising the steps of:

[0139] Providing an SOI wafer, wherein the SOI wafer comprises a substrate, an insulating layer and a top silicon layer stacked in sequence;

[0140] Etching at least two recessed areas on the top silicon surface;

[0141] Bonding the etched SIO wafer to a MEMS acoustic wave device array to form the enclosed space for accommodating the vibration medium based on the recessed area, wherein the MEMS acoustic wave device array includes at least two MEMS acoustic wave devices, each MEMS acoustic wave device is located in a corresponding recessed area;

[0142] The substrate and the insulating layer of the SIO wafer are removed.

[0143] 27. The manufacturing method according to 26, wherein the step of bonding the etched SIO wafer to a MEMS acoustic wave device array comprises the following steps:

[0144] Depositing bonding layers on the SIO wafer and the MEMS acoustic wave device array respectively;

[0145] The bonding layer on the SIO wafer and the bonding layer on the MEMS acoustic wave device array are bonded.

[0146] 28. The method according to 25, comprising the steps of:

[0147] Depositing sacrificial materials on MEMS acoustic wave devices;

[0148] Depositing a packaging film material on the sacrificial material to form a packaging film;

[0149] Etching a release hole on the packaging film and releasing the sacrificial material to form a space for accommodating a vibration medium;

[0150] A sealing layer is provided on the packaging film to seal the release hole to form the closed space for accommodating the vibration medium.

[0151] 29. The method according to 25, comprising the steps of:

[0152] Providing a polymer encapsulation film, wherein the polymer encapsulation film has a recessed area;

[0153] The polymer packaging film is bonded to the MEMS acoustic wave device to form the closed space for accommodating the vibration medium based on the recessed area, wherein the MEMS acoustic wave device is located in the recessed area.

[0154] 30. The manufacturing method according to 29, wherein after bonding the polymer encapsulation film to the MEMS acoustic wave device, further comprising the steps of:

[0155] An external electrical connection component is formed on the polymer packaging film.

[0156] 31. An electronic device comprising a MEMS ultrasonic transducer according to any one of 1 to 24 or a MEMS ultrasonic transducer manufactured according to any one of 25 to 30.

[0157] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A MEMS ultrasonic transducer, comprising: MEMS acoustic wave devices adapted to vibrate to generate ultrasonic waves or to be excited by ultrasonic waves to vibrate; and A packaging layer is used to package the MEMS acoustic wave device so as to form a closed space for accommodating a vibration medium between the packaging layer and the MEMS acoustic wave device, wherein: Based on the enclosed space, the packaging layer is suitable for transmitting the vibration of the acoustic wave device to the outside or transmitting external vibration to the acoustic wave device.

2. The MEMS ultrasonic transducer according to claim 1, wherein: The MEMS acoustic wave device is disposed on a substrate; The acoustic wave device is provided with a first vibration space and a second vibration space on both sides in the thickness direction of the acoustic wave device respectively; The first vibration space is arranged between the first side of the acoustic wave device and the substrate or in the substrate, and the second vibration space is the closed space.

3. The MEMS ultrasonic transducer according to claim 2, wherein: The packaging layer is arranged on a second side of the acoustic wave device opposite to the first side, the second vibration space is arranged between the second side of the acoustic wave device and the packaging layer, the first vibration space and the second vibration space have an overlapping area in the thickness direction of the acoustic wave device, and the first effective vibration area of ​​the acoustic wave device is arranged in the overlapping area in the thickness direction of the acoustic wave device; The encapsulation layer is provided with a second effective vibration region opposite to the first effective vibration region.

4. The MEMS ultrasonic transducer according to claim 3, wherein: The effective stiffness of the second effective vibration area is not higher than 8 times the effective stiffness of the first effective vibration area.

5. The MEMS ultrasonic transducer according to claim 4, wherein: An effective stiffness of the second effective vibration region is not higher than an effective stiffness of the first effective vibration region.

6. The MEMS ultrasonic transducer according to claim 2, wherein: The acoustic wave device comprises a MEMS acoustic wave device.

7. The MEMS ultrasonic transducer according to claim 6, wherein: The acoustic wave device is a bi-piezoelectric chip structure.

8. The MEMS ultrasonic transducer according to any one of claims 2 to 7, wherein: The encapsulation layer includes an encapsulation film.

9. The MEMS ultrasonic transducer according to claim 8, wherein: The packaging film is a closed film layer.

10. The MEMS ultrasonic transducer according to claim 8, wherein: The packaging film is provided with a release hole, and the release hole is communicated with the enclosed space; The packaging layer further includes a sealing layer covering a side of the packaging film away from the acoustic wave device so as to cover the release hole.

11. The MEMS ultrasonic transducer according to claim 8, wherein: The material of the encapsulation film is one of silicon, silicon nitride, silicon oxide, aluminum nitride or aluminum oxide, and polymer.

12. The MEMS ultrasonic transducer according to any one of claims 2 to 7, wherein: The acoustic wave device is a first acoustic wave device; The packaging layer includes a second acoustic wave device, the second acoustic wave device is overlapped with the first acoustic wave device in a thickness direction of the first acoustic wave device, and the second vibration space is provided between the second acoustic wave device and the first acoustic wave device.

13. The MEMS ultrasonic transducer according to claim 12, wherein: The packaging layer also includes a third acoustic wave device, and the third acoustic wave device, the second acoustic wave device and the first acoustic wave device are stacked in the thickness direction of the first acoustic wave device, the second vibration space is arranged between the second acoustic wave device and the first acoustic wave device, and the third vibration space is arranged between the second acoustic wave device and the third acoustic wave device.

14. The MEMS ultrasonic transducer according to claim 13, wherein: The second vibration space and the third vibration space are closed spaces; or The second vibration space is a closed space, and the third vibration space is a non-closed space.

15. The MEMS ultrasonic transducer according to claim 13, wherein: The first acoustic wave device and the second acoustic wave device are bimorph structures.

16. The MEMS ultrasonic transducer according to any one of claims 2 to 7, wherein: The ultrasonic transducer includes at least two acoustic wave devices, and the at least two acoustic wave devices are arranged in the same layer and share the packaging layer.

17. The MEMS ultrasonic transducer according to claim 1, wherein: The MEMS acoustic wave device and the packaging layer have the same resonance frequency.

18. The MEMS ultrasonic transducer according to claim 17, wherein: At least one of the MEMS acoustic wave device, the vibration medium and the packaging layer operates in a resonant state.

19. The MEMS ultrasonic transducer according to claim 17, wherein: At least two of the MEMS acoustic wave device, the vibration medium and the packaging layer operate in a resonant state.

20. The MEMS ultrasonic transducer according to claim 1, wherein: The encapsulation layer is an encapsulation film.

21. The MEMS ultrasonic transducer according to claim 20, wherein: The material of the encapsulation film is one of silicon, silicon nitride, silicon oxide, aluminum nitride or aluminum oxide, and polymer.

22. The MEMS ultrasonic transducer according to claim 1, wherein: The MEMS acoustic wave device is a back-engraved type MEMS acoustic wave device.

23. The MEMS ultrasonic transducer according to claim 1, wherein: The vibration medium is air, and the air pressure in the closed cavity is not less than 100 Pa; or The vibration medium is liquid.

24. A MEMS ultrasonic transducer, comprising: MEMS acoustic wave devices; A packaging layer, used for packaging MEMS acoustic wave devices; A sealed vibration medium layer is provided between the packaging layer and the MEMS acoustic wave device. Wherein: the sound wave is transmitted outward through the path of MEMS sound wave device-vibration medium layer-packaging layer, or is transmitted inward through packaging layer-vibration medium layer-MEMS sound wave device.

25. A method for manufacturing a MEMS ultrasonic transducer, comprising the steps of: Providing a MEMS acoustic wave device, the MEMS acoustic wave device is suitable for vibrating to generate ultrasonic waves or being excited by ultrasonic waves to generate vibrations; The MEMS acoustic wave device is encapsulated by the encapsulation layer, so that a closed space for accommodating the vibration medium is formed between the encapsulation layer and the MEMS acoustic wave device. in: Based on the enclosed space, the packaging layer is suitable for transmitting the vibration of the acoustic wave device to the outside or transmitting external vibration to the acoustic wave device.

26. The method according to claim 25, comprising the steps of: Providing an SOI wafer, wherein the SOI wafer comprises a substrate, an insulating layer and a top silicon layer stacked in sequence; Etching at least two recessed areas on the top silicon surface; The etched SIO wafer is bonded to a MEMS acoustic wave device array to form the closed space for accommodating the vibration medium based on the recessed area, wherein: The MEMS acoustic wave device array includes at least two MEMS acoustic wave devices, each MEMS acoustic wave device is located in a corresponding recessed area; The substrate and the insulating layer of the SIO wafer are removed.

27. The manufacturing method according to claim 26, wherein: The step of bonding the etched SIO wafer to a MEMS acoustic wave device array comprises the following steps: Depositing bonding layers on the SIO wafer and the MEMS acoustic wave device array respectively; The bonding layer on the SIO wafer and the bonding layer on the MEMS acoustic wave device array are bonded.

28. The method according to claim 25, comprising the steps of: Depositing sacrificial materials on MEMS acoustic wave devices; Depositing a packaging film material on the sacrificial material to form a packaging film; Etching a release hole on the packaging film and releasing the sacrificial material to form a space for accommodating a vibration medium; A sealing layer is provided on the packaging film to seal the release hole to form the closed space for accommodating the vibration medium.

29. The method according to claim 25, comprising the steps of: A polymer encapsulation film is provided, wherein: The polymer encapsulation film has a recessed area; The polymer packaging film is bonded to the MEMS acoustic wave device to form the closed space for accommodating the vibration medium based on the recessed area, wherein the MEMS acoustic wave device is located in the recessed area.

30. The manufacturing method according to claim 29, wherein: After bonding the polymer packaging film to the MEMS acoustic wave device, the method further comprises the following steps: An external electrical connection component is formed on the polymer packaging film.

31. An electronic device comprising the MEMS ultrasonic transducer according to any one of claims 1-24 or the MEMS ultrasonic transducer manufactured by the method according to any one of claims 25-30.

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