Manufacturing method of micro electro mechanical system loudspeaker

Abstract

The invention discloses a manufacturing method of a micro electro mechanical system (MEMS) loudspeaker, which comprises the following steps of: forming an actuating structure, the actuating structure comprises a substrate structure, a first electrode located on one side of the substrate structure, a piezoelectric film layer located on the side, away from the substrate structure, of the first electrode, and a second electrode located on the side, away from the first electrode, of the piezoelectric film layer. Forming a supporting layer on one side, far away from the first electrode, of the piezoelectric film layer; forming a sacrificial layer on one side, far away from the piezoelectric film layer, of the second electrode; the sacrificial layer comprises a first groove structure; a hard vibrating diaphragm layer is formed on the side, away from the second electrode, of the sacrificial layer, the hard vibrating diaphragm layer covers the supporting layer and the sacrificial layer, and the hard vibrating diaphragm layer comprises a bent structure and a planar structure; forming a first through hole in the first substrate; and removing the sacrificial layer. The invention provides a manufacturing method of a micro-electro-mechanical system loudspeaker, which can improve the output performance of the micro-electro-mechanical system loudspeaker and reduce the manufacturing cost of the micro-electro-mechanical system loudspeaker.

Description

Technical Field

[0001] The present invention relates to the technical field of loudspeakers, and in particular to a method for manufacturing a micro-electromechanical system loudspeaker. Background Art

[0002] Speakers have been widely used in computers, smart phones, headphones, earplugs, high-fidelity hearing aids, the Internet of Things and other fields. In recent years, with the growing demand for miniaturized, low-cost, and low-power consumer electronic products, the demand for small and micro-micro-electro-mechanical system (MEMS) speakers has increased. Compared with traditional speakers such as electromagnetic speakers, piezoelectric MEMS speakers have the advantages of simple structure, small size, and low cost; and compared with capacitive speakers, which are also MEMS devices, piezoelectric MEMS speakers have the advantages of strong environmental tolerance, simple circuit ASIC design, and high sensitivity. Recently, they have become a research hotspot.

[0003] like Figure 1 and Figure 2 As shown, Figure 1 It is a structural schematic diagram of a piezoelectric MEMS speaker in a non-vibration state provided by the related technology. Figure 2 It is a structural schematic diagram of a piezoelectric MEMS speaker under vibration provided by the related technology. The piezoelectric MEMS speaker usually drives the piezoelectric film 110 to drive the silicon film 120 to vibrate up and down, thereby producing sound. Usually, due to the fully enclosed constraint conditions between the entire piezoelectric film 110 and the supporting frame 130 and the limited vibration amplitude caused by the residual stress, the piezoelectric MEMS speaker generally performs slit etching on the piezoelectric film 110 to form slits 111, so that the entire piezoelectric film 110 is separated into several independent smaller diaphragms 112, and the constraint at one end of the piezoelectric film 110 is released to obtain a greater degree of freedom, thereby bringing a larger amplitude and sound pressure level (SPL), where the sound pressure level refers to the total intensity of the sound received by the listener.

[0004] However, for the speaker, the air leaking through the slit 111 will cause sound pressure loss due to acoustic short circuit (acoustic short circuit means that the sound waves are in opposite phases when the diaphragm of the speaker moves forward or backward, resulting in the sound waves canceling each other out), making it difficult for the performance of the piezoelectric MEMS speaker to reach the level of a traditional speaker. The sound pressure level SPL of the speaker follows the following formula:

[0005] SPL∝A·f·d

[0006] Wherein, A is the effective diaphragm area, f is the signal frequency, and d is the equivalent vibration displacement of the diaphragm at the frequency. It can be seen from the formula that when the slit 111 is wider, the effective diaphragm area is smaller, and the output sensitivity and sound pressure level of the speaker are lower, especially for low-frequency sound source signals.

[0007] In addition, various current speaker structures all have the problem of small overall effective diaphragm area. Figure 3 yes Figure 1 The simulation results of the structure shown in the figure under vibration are shown in Figure 1. Figure 3 After applying an external electric field drive, although the constraints of the entire diaphragm have been reduced by etching the slits, the working mode of the piezoelectric film determines that the diaphragm will basically not deform at the fixed end (i.e., the intersection with the base), and the farther away from the fixed end and closer to the free end near the slit, the greater the deformation. This makes it difficult for piezoelectric MEMS speakers to effectively utilize their diaphragm area. Although the diaphragm area is large, the area that can effectively vibrate and produce sound is extremely limited.

[0008] In addition, during the manufacturing process, the piezoelectric film will have a certain amount of residual stress, which will cause the diaphragm to warp and the vibration output of the diaphragm to be distorted, such as the different initial positions of multiple diaphragms and vibration distortion. Moreover, since the residual stress is affected by the process conditions and has a certain degree of randomness, it is difficult to control and will also have a certain impact on the yield of the device.

[0009] In order to compensate for the SPL loss caused by the slit and improve the consistency and uniformity between independent diaphragms, a commonly used method is to obtain the basic structure of the piezoelectric MEMS microphone, use it as a driving device, and attach an additional diaphragm on its basis.

[0010] However, after the MEMS device process is completed, the corresponding structure of the diaphragm is additionally attached. This method requires additional manual assembly. Due to the small size of MEMS devices, high assembly precision is required, which will lead to higher labor costs and reduce production efficiency, thus causing MEMS devices to lose their original advantages such as high process consistency, mass production, and low cost. Summary of the invention

[0011] The present invention provides a method for manufacturing a micro-electro-mechanical system loudspeaker, which can improve the output performance of the micro-electro-mechanical system loudspeaker and reduce the manufacturing cost of the micro-electro-mechanical system loudspeaker.

[0012] The present invention provides a method for manufacturing a micro-electromechanical system loudspeaker, the manufacturing method comprising:

[0013] An actuating structure is formed, wherein the actuating structure comprises a substrate structure, a first electrode located at one side of the substrate structure, a piezoelectric film layer located at a side of the first electrode away from the substrate structure, and a second electrode located at a side of the piezoelectric film layer away from the first electrode; the substrate structure comprises a first substrate and a second substrate stacked in layers; the second substrate is located between the first substrate and the first electrode; the second substrate comprises a plurality of first slits; the first electrode comprises a plurality of second slits, the piezoelectric film layer comprises a plurality of third slits, and the third slits, the second slits and the first slits are connected;

[0014] A support layer is formed on a side of the piezoelectric film layer away from the first electrode, wherein the support layer comprises a support ring and a support column, the support ring is located at the edge of the piezoelectric film layer, and the support ring is arranged around the support column;

[0015] A sacrificial layer is formed on a side of the second electrode away from the piezoelectric film layer, wherein the sacrificial layer exposes the support layer and fills the gap between the support ring and the support column; the sacrificial layer includes a first groove structure;

[0016] A hard diaphragm layer is formed on a side of the sacrificial layer away from the second electrode, wherein the hard diaphragm layer covers the support layer and the sacrificial layer, the hard diaphragm layer includes a bent structure and a planar structure, and a vertical projection of the bent structure on the second substrate overlaps with a vertical projection of the first groove structure on the second substrate;

[0017] forming a first through hole in the first substrate, wherein the first through hole is connected to the first slit;

[0018] The sacrificial layer is removed.

[0019] Optionally, forming a sacrificial layer on a side of the second electrode away from the piezoelectric film layer includes:

[0020] A first sacrificial transition layer is formed on a side of the second electrode away from the piezoelectric film layer; wherein the first sacrificial transition layer covers the support layer and fills the gap between the support ring and the support column;

[0021] Processing the first sacrificial transition layer so that the processed first sacrificial transition layer exposes the support layer;

[0022] forming a first mask layer on a side of the processed first sacrificial transition layer away from the second electrode; wherein the first mask layer covers the support layer and the processed first sacrificial transition layer;

[0023] forming a second sacrificial transition layer on a side of the first mask layer away from the piezoelectric film layer;

[0024] Processing the second sacrificial transition layer so that the processed second sacrificial transition layer includes a first through-hole structure; wherein the first through-hole structure exposes at least a portion of the first mask layer;

[0025] The first mask layer is processed using the processed second sacrificial transition layer as a mask, so that the processed first mask layer includes a second through-hole structure; wherein the second through-hole structure exposes at least a portion of the processed first sacrificial transition layer;

[0026] At the same time, etching the processed second sacrificial transition layer and the first sacrificial transition layer exposed by the first mask layer until the second sacrificial transition layer is completely etched to form the sacrificial layer;

[0027] The remaining first mask layer is removed.

[0028] Optionally, the first groove structure includes a first groove substructure and a plurality of second groove substructures;

[0029] The first groove substructure is adjacent to the support ring and surrounds one side of the support ring close to the support column;

[0030] The vertical projections of the plurality of second groove substructures on the substrate structure surround the vertical projection of the support column on the substrate structure, and the vertical projections of the plurality of second groove substructures on the substrate structure are distributed in a whirlwind manner.

[0031] Optionally, forming the actuation structure includes:

[0032] Providing a substrate transition structure, wherein the substrate transition structure comprises the first substrate and the second transition substrate which are stacked;

[0033] A first electrode transition layer and a piezoelectric film transition layer are formed on a side of the second transition substrate away from the first substrate; wherein the first electrode transition layer covers the second transition substrate; and the piezoelectric film transition layer covers the first electrode transition layer;

[0034] Processing the piezoelectric film transition layer to form the piezoelectric film layer;

[0035] forming the second electrode on a side of the piezoelectric film layer away from the first electrode transition layer;

[0036] Processing the first electrode transition layer to form the first electrode;

[0037] The second transition substrate is processed to form the second substrate to form the actuation structure.

[0038] Optionally, the hard diaphragm layer is formed on a side of the sacrificial layer away from the second electrode, comprising:

[0039] The hard diaphragm layer is formed on a side of the sacrificial layer away from the second electrode by using an evaporation process.

[0040] Optionally, the first substrate includes a first sub-substrate and a second sub-substrate which are stacked, and the second sub-substrate is located between the first sub-substrate and the second substrate;

[0041] The forming of a first through hole in the first substrate comprises:

[0042] A first sub-through hole is formed in the first sub-substrate;

[0043] A second sub-through hole is formed in the second sub-substrate, wherein the first sub-through hole and the second sub-through hole constitute the first through hole.

[0044] Optionally, the material of the support layer includes a high molecular polymer;

[0045] The material of the sacrificial layer includes positive photoresist.

[0046] Optionally, the actuation structure further includes an exposed first pad and a second pad; the first pad is electrically connected to the first electrode, and the second pad is electrically connected to the second electrode.

[0047] Optionally, the support layer has a thickness ranging from 50 μm to 150 μm.

[0048] Optionally, a vertical projection of the second slit on the second substrate covers the first slit; and a vertical projection of the third slit on the second substrate covers a vertical projection of the second slit on the second substrate.

[0049] An embodiment of the present invention provides a method for manufacturing a micro-electromechanical system speaker, the method for manufacturing a micro-electromechanical system speaker comprising: first forming an actuating structure, wherein the actuating structure comprises a substrate structure, a first electrode, a piezoelectric film layer and a second electrode. Then forming a support layer on the side of the piezoelectric film layer away from the first electrode, wherein the support layer comprises a support ring and a support column, and the support ring is located at the edge of the piezoelectric film layer and surrounds the support column. Then forming a sacrificial layer on the side of the second electrode away from the piezoelectric film layer, wherein the sacrificial layer comprises a first groove structure. Then forming a hard diaphragm layer on the side of the sacrificial layer away from the second electrode, wherein the hard diaphragm layer comprises a bending structure and a planar structure, and the vertical projection of the bending structure on the second substrate overlaps with the vertical projection of the first groove structure on the second substrate. Then forming a first through hole connected to the first slit in the first substrate, and finally removing the sacrificial layer to form a micro-electromechanical system speaker. The support layer in the MEMS speaker manufactured by the manufacturing method provided by this embodiment constructs an additional cavity on one side of the piezoelectric diaphragm layer. The support layer can transmit the maximum center vibration generated by the piezoelectric film layer to the hard diaphragm layer on the top, and the hard diaphragm layer replaces the piezoelectric film layer to vibrate and produce sound. Compared with other structures, the maximum center displacement of the piezoelectric braking structure can be fully utilized to greatly improve the SPL output by the MEMS speaker. The bending vibration of the piezoelectric film layer can also be converted into the vertical vibration of the external hard diaphragm layer, so that the sound waves emitted by the MEMS speaker are purer, THD (harmonic distortion) is reduced, and the comprehensive performance of the MEMS speaker is improved. The process of manufacturing the hard diaphragm layer in this embodiment is compatible with the existing MEMS process, and does not require subsequent manual assembly and other operations, so that the consistency and reliability of the MEMS speaker are guaranteed, and it has the advantage of low cost. In summary, the manufacturing method of the MEMS speaker provided by this embodiment can improve the output performance of the MEMS speaker and reduce the manufacturing cost of the MEMS speaker.

[0050] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0052] Figure 1 It is a structural schematic diagram of a piezoelectric MEMS speaker in a non-vibration state provided by the related technology;

[0053] Figure 2 It is a structural schematic diagram of a piezoelectric MEMS speaker under vibration provided by the related technology;

[0054] Figure 3 yes Figure 1 The simulation result diagram of the structure shown in the vibration condition;

[0055] Figure 4 is a flow chart of a method for manufacturing a micro-electromechanical system speaker provided according to an embodiment of the present invention;

[0056] Figure 5 is a schematic diagram of a top view of an actuating structure provided in an embodiment of the present invention;

[0057] Figure 6 is along Figure 5 A schematic diagram of a cross-sectional structure obtained by cutting along the section line A1A2 in FIG.

[0058] Figure 7 is a schematic diagram of a top view structure of a second substrate provided according to an embodiment of the present invention;

[0059] Figure 8 is a schematic diagram of a top view structure of a first electrode provided according to an embodiment of the present invention;

[0060] Fig. 9 is a schematic diagram of a top view structure of a piezoelectric film layer provided according to an embodiment of the present invention;

[0061] Fig.10 is a schematic diagram of a top view structure of a second electrode provided according to an embodiment of the present invention;

[0062] Fig.11 is a schematic diagram of a top view of the structure after a support layer is formed on one side of the actuating structure;

[0063] Fig.12 For along Fig.11 A schematic diagram of the structure obtained by cutting along the section line B1B2 in FIG.

[0064] Fig.13 is a schematic diagram of a top view structure of a support layer provided according to an embodiment of the present invention;

[0065] Fig.14 A schematic diagram of a top view structure after forming a sacrificial layer;

[0066] Fig.15 For along Fig.14 A schematic diagram of the structure obtained by cutting along the section line C1C2 in FIG.

[0067] Fig.16It is another schematic diagram of a top view structure after forming a sacrificial layer;

[0068] Fig.17 A schematic diagram of a top view structure after a hard diaphragm layer is formed;

[0069] Fig.18 For along Fig.17 A schematic diagram of the structure obtained by cutting along the section line D1D2 in FIG.

[0070] Fig.19 It is another schematic diagram of a top view structure after forming a hard diaphragm layer;

[0071] Fig. 20 is a schematic diagram of the structure after the first through hole is formed;

[0072] Fig.21 is a schematic structural diagram of a MEMS speaker manufactured according to the method for manufacturing a MEMS speaker provided in an embodiment of the present invention;

[0073] Fig. 22 yes Fig.21 The schematic diagram of the structure of the MEMS speaker when producing sound is shown;

[0074] Fig.23 is a flow chart of another method for manufacturing a MEMS speaker according to an embodiment of the present invention;

[0075] Fig.24 is a schematic diagram of the structure after the first sacrificial transition layer is formed;

[0076] Fig.25 is a schematic structural diagram of a first sacrificial transition layer after treatment;

[0077] Fig.26 is a schematic diagram of the structure after the first mask layer is formed;

[0078] Fig. 27 is a schematic diagram of the structure after the second sacrificial transition layer is formed;

[0079] Fig.28 is a schematic structural diagram of a second sacrificial transition layer after treatment;

[0080] Fig.29 is a schematic structural diagram of a first mask layer after processing;

[0081] Fig.30 is another structural schematic diagram after forming a sacrificial layer;

[0082] Figure 31-Figure 35 is a schematic diagram of the process structure of forming the actuating structure;

[0083] Fig.36is a schematic diagram of the structure after the first sub-through hole is formed;

[0084] Fig.37 is a structural schematic diagram of another actuating structure provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0085] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0086] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0087] Figure 4 FIG. 1 is a flow chart of a method for manufacturing a MEMS speaker according to an embodiment of the present invention, referring to FIG. Figure 4 The manufacturing method provided in this embodiment includes the following steps:

[0088] S110, forming an actuating structure.

[0089] in, Figure 5 is a schematic diagram of a top view of an actuating structure provided according to an embodiment of the present invention, Figure 6 is along Figure 5 A schematic diagram of a cross-sectional structure obtained by cutting the section line A1A2 in FIG. Figure 7 is a schematic diagram of a top view of a second substrate provided according to an embodiment of the present invention, Figure 8 is a schematic diagram of a top view structure of a first electrode provided according to an embodiment of the present invention, Fig. 9 is a schematic diagram of a top view structure of a piezoelectric film layer provided according to an embodiment of the present invention, Fig.10 is a schematic diagram of a top view of a second electrode provided according to an embodiment of the present invention, with reference to Figure 5-Figure 10The actuating structure 200 provided in this embodiment includes a substrate structure 210, a first electrode 220 located on one side of the substrate structure 210, a piezoelectric film layer 230 located on a side of the first electrode 220 away from the substrate structure 210, and a second electrode 240 located on a side of the piezoelectric film layer 230 away from the first electrode 220; the substrate structure 210 includes a first substrate 211 and a second substrate 212 stacked; the second substrate 212 is located between the first substrate 211 and the first electrode 220; the second substrate 212 includes a plurality of first slits 202; the first electrode 220 includes a plurality of second slits 203, the piezoelectric film layer 230 includes a plurality of third slits 204, and the third slits 204, the second slits 203 and the first slits 202 are connected; the second electrode 240 includes a plurality of second sub-electrodes 241 electrically connected to each other, and the first slit 202, the second slit 203 and the third slit 203 are located in the gap between two adjacent second sub-electrodes 241.

[0090] Specifically, the number of the first slits 202, the number of the second slits 203, and the number of the third slits 204 may be equal. For example, the number of the first slits 202 may be 4. The first slits 202 may correspond to the second slits 203 one by one, and each first slit 202 is connected to the corresponding second slit 203. The second slits 203 may correspond to the third slits 204 one by one, and each second slit 203 is connected to the corresponding third slit 204. The shapes of the first slits 202, the shapes of the second slits 203, and the shapes of the third slits 204 may be the same, but the sizes may be different. For example, the shape of the first slits 202 may be rectangular.

[0091] The vertical projection of the first electrode 220 on the second substrate 212, the vertical projection of the piezoelectric film layer 230 on the second substrate 212, and the vertical projection of the second electrode 240 on the second substrate 212 overlap each other. After the first electrode 220 and the second electrode 240 input an electrical signal, the piezoelectric film layer 230 can convert the electrical signal into displacement. In this embodiment, the first slit 202, the second slit 203, and the third slit 204 are connected and located at the gap between two adjacent second sub-electrodes 241, so that the piezoelectric film layer 230 can be separated into several independent smaller piezoelectric film sub-layers, and the constraint of one end of the piezoelectric film layer 230 can be released to obtain a greater degree of freedom, thereby bringing a larger amplitude and SPL.

[0092] Continue to refer Fig.10 The second electrode 240 further includes a plurality of connecting electrodes 242, and the connecting electrodes 242 are used to electrically connect two adjacent second sub-electrodes 241. The second electrode 240 is not disposed at the center of the piezoelectric film layer 230, and the material of the piezoelectric film layer 230 may be lead zirconate titanate (PZT).

[0093] S120, forming a support layer on a side of the piezoelectric film layer away from the first electrode.

[0094] in, Fig.11 is a schematic diagram of a top view of the structure after a support layer is formed on one side of the actuating structure. Fig.12 For along Fig.11 The schematic diagram of the structure obtained by cutting the section line B1B2 in FIG. Fig.13 is a schematic diagram of a top view of a support layer provided according to an embodiment of the present invention, with reference to Figure 11-13 The support layer 250 includes a support ring 251 and a support column 252 . The support ring 251 is located at the edge of the piezoelectric film layer 240 , and the support ring 251 is arranged around the support column 252 .

[0095] Specifically, the support layer 250 and the second electrode 240 may be located on the surface of the piezoelectric film layer 230 away from the substrate structure 210, the support ring 251 is distributed around the second electrode 240, and the vertical projection of the support column 252 on the piezoelectric film layer 230 may cover the center of the piezoelectric film layer 230. The vertical projection of the support column 252 on the piezoelectric film layer 230 includes a plurality of third slits 204 around it.

[0096] A polymer layer of a certain thickness can be formed on the surface of the piezoelectric film layer 230 away from the first electrode 220 by gluing or coating, and the polymer layer covers the piezoelectric film layer 240 and the second electrode 240 , and then is cured by photolithography, development and curing to form the support layer 250 .

[0097] The vertical projection of the second electrode 420 on the piezoelectric film layer 230 may not overlap with the vertical projection of the support layer 250 on the piezoelectric film layer 230. The vertical projection of the first electrode 220 on the second substrate 212 overlaps with the vertical projection of the support pillar 252 on the second substrate 212.

[0098] S130, forming a sacrificial layer on a side of the second electrode away from the piezoelectric film layer.

[0099] in, Fig.14 A schematic diagram of a top view structure after forming a sacrificial layer. Fig.15 For along Fig.14 The schematic diagram of the structure obtained by cutting the section line C1C2 in Fig.14 and Fig.15 The sacrificial layer 310 exposes the supporting layer 250 and fills the gap between the supporting ring 251 and the supporting column 252 ; the sacrificial layer 310 includes a first groove structure 311 .

[0100] Specifically, the first groove structure 311 extends from the surface of the sacrificial layer 310 away from the second electrode 240 to the inside of the sacrificial layer 310, and the depth of the first groove structure 311 is less than the thickness of the sacrificial layer 310. The sacrificial layer 310 also fills the first gap, the second gap and the third gap. The first groove structure 311 can be adjacent to the support ring 251 and located on the inner side of the support ring 251. The first groove structure 311 can also be located inside the sacrificial layer 310. For example, Fig.16 Another schematic diagram of a top view structure after forming a sacrificial layer is shown in FIG. Fig.16 The first groove structure 311 includes a first groove substructure 3111 and a second groove substructure 3112 . The first groove substructure 3111 is adjacent to the support ring 251 and is located on the inner side of the support ring 251 . The second groove substructure 3112 is located inside the sacrificial layer 310 .

[0101] The first groove structure 311 may include a plurality of first grooves, each of which may have the same depth. The longitudinal section of the first groove may be any one of a rectangular, a trapezoidal, an inverted trapezoidal, a triangular or an arcuate shape. Part of the sacrificial layer 310 may also cover the edge of the support layer 250.

[0102] S140, forming a hard diaphragm layer on a side of the sacrificial layer away from the second electrode.

[0103] in, Fig.17 A schematic diagram of a top view structure after the hard diaphragm layer is formed. Fig.18 For along Fig.17 The schematic diagram of the structure obtained by cutting the section line D1D2 in Fig.17 and Fig.18 The hard diaphragm layer 260 covers the support layer 250 and the sacrificial layer 310 , and the hard diaphragm layer 260 includes a bending structure 261 and a planar structure 262 . The vertical projection of the bending structure 261 on the second substrate 212 overlaps with the vertical projection of the first groove structure 311 on the second substrate 212 .

[0104] Specifically, a hard diaphragm layer 260 can be formed by an evaporation process on the side of the sacrificial layer 310 away from the second electrode 240, so that the change trend of the bending structure 261 can be the same as the change trend of the first groove structure 311, so that the vertical projection of the bending structure 261 on the second substrate coincides with the vertical projection of the first groove structure 311 on the second substrate. Fig.19 Another schematic diagram of a top view structure after forming a hard diaphragm layer, when the first groove structure is Fig.16 When the structure shown in FIG. 1 is formed, a hard diaphragm layer 260 is formed as shown in FIG. Fig.19The process of forming the hard diaphragm layer 260 in this embodiment is compatible with the MEMS process, and does not require subsequent manual assembly operations to form the hard diaphragm layer 260 on one side of the actuating structure. It can be seen that the manufacturing method provided in this embodiment can reduce the manufacturing cost.

[0105] S150 , forming a first through hole in the first substrate.

[0106] in, Fig. 20 is a schematic diagram of the structure after the first through hole is formed, refer to Fig. 20 , the first through hole 201 is connected to the first slit.

[0107] Specifically, the first through hole 201 is formed in the first substrate 211 to completely release the actuation structure.

[0108] S160, removing the sacrificial layer.

[0109] Specifically, Fig.21 FIG. 1 is a schematic diagram of the structure of a MEMS speaker manufactured according to a method for manufacturing a MEMS speaker provided in an embodiment of the present invention, with reference to FIG. Fig. 20 and Fig.21 Since the first through hole 201 is connected to the first slit 202, and the first slit 202, the second slit 203 and the third slit 204 are connected to each other, when removing the sacrificial layer 310, the structure formed in step S150 can be immersed in the set solution as a whole, and the sacrificial layer 310 can be removed by wet immersion, thereby releasing the hard diaphragm layer 260.

[0110] The support layer 250 and the hard diaphragm layer 260 can construct an additional cavity above the piezoelectric film layer 230 of the MEMS speaker. A support column 252 is arranged at the center of the piezoelectric film layer 230, so that the support column 252 can transmit the vibration generated by the piezoelectric film layer 230 to the hard diaphragm layer 260, and the support ring 251 can also transmit the vibration generated by the piezoelectric film layer 230 to the hard diaphragm layer 260.

[0111] Fig. 22 yes Fig.21 The schematic diagram of the structure of the MEMS speaker when it is sounding is shown in FIG. Fig. 22The working principle of the MEMS speaker provided in this embodiment is as follows: after the first electrode 220 and the second electrode 240 input an electrical signal, the piezoelectric film layer 230 converts the electrical signal into displacement, and the piezoelectric film layer 230 acts as a driving device to drive the support layer 250, and finally relies on the vibration of the hard diaphragm layer 260 to produce sound, and can effectively conduct the maximum displacement of the piezoelectric film layer 230 to the hard diaphragm layer 260. In addition, because the harder hard diaphragm layer 260 can better push the air to achieve better sound quality when vibrating and producing sound, the harder diaphragm layer 260 will also bring constraints to the vibrating part of the piezoelectric film layer 230, resulting in the vibration of the piezoelectric film layer 230 being limited, thereby reducing the overall sound pressure output. In the present invention, a bending structure 261 is added to the hard diaphragm layer 260 under the condition of compatibility with the MEMS process, and the additional constraints and burdens on the piezoelectric film layer 230 are reduced without substantially reducing the effective area of ​​the hard diaphragm layer 260, thereby ensuring a larger output SPL of the MEMS speaker.

[0112] It should be noted that the top view of the MEMS speaker manufactured in this embodiment shows that the MEMS speaker is rectangular in shape, but this is not a limitation of the present invention. The MEMS speaker provided in this embodiment may also be circular or other polygonal in shape.

[0113] The present embodiment provides a method for manufacturing a micro-electromechanical system speaker, and the method for manufacturing a micro-electromechanical system speaker includes: first forming an actuating structure, wherein the actuating structure includes a substrate structure, a first electrode, a piezoelectric film layer, and a second electrode. Then forming a support layer on the side of the piezoelectric film layer away from the first electrode, wherein the support layer includes a support ring and a support column, and the support ring is located at the edge of the piezoelectric film layer and surrounds the support column. Then forming a sacrificial layer on the side of the second electrode away from the piezoelectric film layer, wherein the sacrificial layer includes a first groove structure. Then forming a hard diaphragm layer on the side of the sacrificial layer away from the second electrode, wherein the hard diaphragm layer includes a bending structure and a planar structure, and the vertical projection of the bending structure on the second substrate overlaps with the vertical projection of the first groove structure on the second substrate. Then forming a first through hole connected to the first slit in the first substrate, and finally removing the sacrificial layer to form a micro-electromechanical system speaker. The support layer in the MEMS speaker manufactured by the manufacturing method provided by this embodiment constructs an additional cavity on one side of the piezoelectric diaphragm layer. The support layer can transmit the maximum center vibration generated by the piezoelectric film layer to the hard diaphragm layer on the top, and the hard diaphragm layer replaces the piezoelectric film layer to vibrate and produce sound. Compared with other structures, the maximum center displacement of the piezoelectric braking structure can be fully utilized to greatly improve the SPL output by the MEMS speaker. The bending vibration of the piezoelectric film layer can also be converted into the vertical vibration of the external hard diaphragm layer, so that the sound waves emitted by the MEMS speaker are purer, THD (harmonic distortion) is reduced, and the comprehensive performance of the MEMS speaker is improved. The process of manufacturing the hard diaphragm layer in this embodiment is compatible with the existing MEMS process, and does not require subsequent manual assembly and other operations, so that the consistency and reliability of the MEMS speaker are guaranteed, and it has the advantage of low cost. In summary, the manufacturing method of the MEMS speaker provided by this embodiment can improve the output performance of the MEMS speaker and reduce the manufacturing cost of the MEMS speaker.

[0114] Fig.23 FIG. 1 is a flow chart of another method for manufacturing a MEMS speaker according to an embodiment of the present invention, referring to FIG. Fig.23 The method for manufacturing a MEMS speaker provided in this embodiment includes the following steps:

[0115] S210: forming an actuating structure.

[0116] Specifically, the content of step S210 is the same as that of step S110. For details about the content of step S210, please refer to the description of step S110 in this embodiment, which will not be repeated here.

[0117] S220, forming a support layer on a side of the piezoelectric film layer away from the first electrode.

[0118] Specifically, the content of step S220 is the same as that of step S120. For details about the content of step S220, please refer to the description of step S120 in this embodiment, which will not be repeated here.

[0119] S230 , forming a first sacrificial transition layer on a side of the second electrode away from the piezoelectric film layer.

[0120] in, Fig.24 is a schematic diagram of the structure after the first sacrificial transition layer is formed, refer to Fig.24 The first sacrificial transition layer 320 covers the support layer 250 and fills the gap between the support ring 251 and the support column 252 .

[0121] Specifically, the first sacrificial transition layer can be formed by spraying and spin coating, and the first sacrificial transition layer formed just covers the support layer 250. The material of the first sacrificial transition layer 320 can be positive photoresist. The surface of the first sacrificial transition layer 320 away from the support layer 250 is a flat surface.

[0122] S240, processing the first sacrificial transition layer so that the processed first sacrificial transition layer exposes the supporting layer.

[0123] Specifically, Fig.25 is a schematic diagram of the structure of the first sacrificial transition layer after treatment, referring to Fig.25 , the first sacrificial transition layer 320 can be photolithographically developed so that the first sacrificial transition layer 320 after processing exposes the supporting layer 250. Fig.24 The controllability of the process of the first sacrificial transition layer 320 shown will retain the first sacrificial transition layer 320 at the edge of the support column 252 and the edge of the support ring 251, that is, the processed first sacrificial transition layer 320 can only expose part of the support layer 250, and a part of the processed first sacrificial transition layer 320 can cover the edge of the support column 252 and the edge of the support ring 252.

[0124] S250 , forming a first mask layer on a side of the processed first sacrificial transition layer away from the second electrode.

[0125] in, Fig.26 is a schematic diagram of the structure after the first mask layer is formed, refer to Fig.26 , the first mask layer 330 covers the support layer 250 and the processed first sacrificial transition layer 320 .

[0126] Specifically, silicon dioxide may be grown by chemical vapor deposition (CVD) to form the first mask layer 330 .

[0127] S260 , forming a second sacrificial transition layer on a side of the first mask layer away from the piezoelectric film layer.

[0128] Specifically, Fig. 27 is a schematic diagram of the structure after the second sacrificial transition layer is formed, refer to Fig. 27 , the second sacrificial transition layer 340 completely covers the first mask layer 330. The second sacrificial transition layer 340 can be formed by spin coating on the side of the first mask layer 330 away from the piezoelectric film layer 230. The material of the second sacrificial transition layer 340 can also be positive photoresist. The thickness of the second sacrificial transition layer 340 is equal to the depth of the groove in the bending structure in the hard diaphragm layer 260.

[0129] S270 , processing the second sacrificial transition layer so that the processed second sacrificial transition layer includes a first through-hole structure.

[0130] in, Fig.28 is a schematic diagram of the structure of the second sacrificial transition layer after treatment, referring to Fig.28 After the processing, the first through hole structure 341 in the second sacrificial transition layer 340 exposes at least a portion of the first mask layer 330 .

[0131] Specifically, the second sacrificial transition layer 340 may be photolithographically developed to form a first through-hole structure 341 , and the first through-hole structure 341 includes a plurality of second through-holes.

[0132] S280 , using the processed second sacrificial transition layer as a mask to process the first mask layer, so that the processed first mask layer includes a second through-hole structure.

[0133] in, Fig.29 is a schematic diagram of the structure of the first mask layer after processing, referring to Fig.29 The second through hole structure 331 in the processed first mask layer 330 exposes at least a portion of the processed first sacrificial transition layer 320 .

[0134] Specifically, the first mask layer 330 may be etched by inductively coupled plasma (ICP) etching to form the second through hole structure 331. ICP etching is selective and will stop when etching to the processed first sacrificial transition layer 320. The second through hole structure 331 includes a plurality of third through holes.

[0135] S290, simultaneously etching the processed second sacrificial transition layer and the first sacrificial transition layer exposed by the first mask layer until the second sacrificial transition layer is completely etched to form a sacrificial layer.

[0136] Specifically, Fig.30 This is another structural diagram after forming a sacrificial layer, refer to Fig.30 , the first sacrificial transition layer exposed by the first mask layer 320 is not completely etched. The second sacrificial transition layer after the treatment and the first sacrificial transition layer exposed by the first mask layer 320 can be etched simultaneously by O2 plasma, and the etching time is based on the etching completion of the second sacrificial transition layer. At this time, the etched depth of the first sacrificial transition layer exposed by the first mask layer 320 is equal to the thickness of the second sacrificial transition layer formed in step S260.

[0137] It should be noted that the thickness of the second sacrificial transition layer formed in step S260 is smaller than the thickness of the sacrificial layer.

[0138] S291 , removing the remaining first mask layer.

[0139] Specifically, the structural schematic diagram after removing the remaining first mask layer can continue to refer to Fig.15 .

[0140] S292, forming a hard diaphragm layer on a side of the sacrificial layer away from the second electrode.

[0141] Specifically, the content of step S292 is the same as that of step S140. For details about the content of step S292, please refer to the description of step S140 in this embodiment, which will not be repeated here.

[0142] S293, forming a first through hole in the first substrate.

[0143] Specifically, the content of step S293 is the same as that of step S150. For details about the content of step S293, please refer to the description of step S150 in this embodiment, which will not be repeated here.

[0144] S294, removing the sacrificial layer.

[0145] Specifically, the content of step S294 is the same as that of step S160. For details about the content of step S294, please refer to the description of step S160 in this embodiment, which will not be repeated here.

[0146] It should be noted that the vertical projection of the first through hole structure on the substrate structure, the vertical projection of the second through hole structure on the substrate structure, and the vertical projection of the first groove structure on the substrate structure may overlap.

[0147] Optional, continue to refer to Fig.16The first groove structure 311 includes a first groove substructure 3111 and a plurality of second groove substructures 3112; the first groove substructure 3111 is adjacent to the support ring 251 and surrounds one side of the support ring 251 close to the support column 252; the vertical projections of the plurality of second groove substructures 3112 on the substrate structure surround the vertical projection of the support column 252 on the substrate structure, and the vertical projections of the plurality of second groove substructures 3112 on the substrate structure are distributed in a whirlwind manner.

[0148] Specifically, the bending structure in the hard diaphragm layer 260 has the same changing trend as the first groove structure 311. Fig.19 , when the first groove structure 311 includes a first groove substructure 3111 and a plurality of second groove substructures 3112, the hard diaphragm layer 260 includes a first bending substructure 2611 and a plurality of second bending substructures 2612. The shape and depth of the groove in the first bending substructure 2611 may correspond to and be equal to the shape and depth of the groove in the second bending substructure 2612. In this embodiment, various bending shapes are added to the edge and interior of the hard diaphragm layer 260, which can reduce the additional constraints and burdens on the piezoelectric film layer without substantially reducing the effective area of ​​the hard diaphragm layer 260. The vertical projections of the plurality of second bending substructures 2612 on the substrate structure 210 are arranged in a whirlwind distribution, which can further ensure a larger output SPL of the MEMS speaker.

[0149] Optionally, forming the actuation structure comprises the following steps (combined with reference Figure 31-Figure 35 ):

[0150] S111. Provide a substrate transition structure.

[0151] Among them, reference Fig.31 The substrate transition structure 201 includes a first substrate 211 and a second transition substrate 203 which are stacked.

[0152] Specifically, the substrate transition structure 201 can be a SOI (Silicon-On-Insulator) substrate. The SOI substrate introduces a buried oxide layer between the top silicon and the back substrate. The top silicon serves as the second transition substrate 203. Using the SOI substrate simplifies the film layer structure of the substrate transition structure 201 and saves the preparation cost.

[0153] S112, forming a first electrode transition layer and a piezoelectric film transition layer in sequence on a side of the second transition substrate away from the first substrate.

[0154] Among them, reference Fig.32 The first electrode transition layer 221 covers the second transition substrate 202 , and the piezoelectric film transition layer 231 covers the first electrode transition layer 221 .

[0155] Specifically, the first electrode transition layer 221 and the piezoelectric film transition layer 231 may be formed respectively by sputtering.

[0156] S113, processing the piezoelectric film transition layer to form a piezoelectric film layer.

[0157] Specifically, refer to Fig.33 The piezoelectric thin film transition layer may be etched and patterned by a wet process or a dry process (ICP) to form a piezoelectric thin film layer 230 .

[0158] S114, forming a second electrode on a side of the piezoelectric film layer away from the first electrode transition layer.

[0159] Specifically, refer to Fig.34 A second electrode layer may be grown on a side of the piezoelectric film layer 230 away from the first electrode transition layer 221 and patterned by etching or lift-off to form the second electrode 240 .

[0160] S115, processing the first electrode transition layer to form a first electrode.

[0161] Specifically, refer to Fig.35 , the first electrode transition layer is patterned by IBE dry etching to form the first electrode 220.

[0162] S116, processing the second transition substrate to form a second substrate to form an actuating structure.

[0163] For details, please refer to Figure 6 The second transition substrate is etched by D-RIE etching. Due to the selectivity of the etching method, the etching will stop automatically after reaching the first substrate 211.

[0164] It should be noted that the first substrate 211 in step S111 to step S116 does not include the first through hole. After the second transition substrate is processed, the substrate transition structure 201 is a substrate structure.

[0165] Optionally, forming a hard diaphragm layer on a side of the sacrificial layer away from the second electrode includes: forming the hard diaphragm layer on a side of the sacrificial layer away from the second electrode by using an evaporation process.

[0166] Specifically, in the process of forming the hard diaphragm layer by the evaporation process, the material of the hard diaphragm layer will cover the concave and convex surface of the sacrificial layer, and the change trend of the formed hard diaphragm layer is basically consistent with the change trend of the sacrificial layer. Since the sacrificial layer includes a first groove structure, the formed hard diaphragm layer will include a bending structure.

[0167] Optionally, the first substrate includes a first sub-substrate and a second sub-substrate which are stacked, and the second sub-substrate is located between the first sub-substrate and the second substrate.

[0168] Forming a first through hole in a first substrate includes:

[0169] A first sub-through hole is formed in the first sub-substrate; and a second sub-through hole is formed in the second sub-substrate, wherein the first sub-through hole and the second sub-through hole constitute a first through hole.

[0170] Specifically, Fig.36 The schematic diagram of the structure after forming the first sub-through hole is shown in FIG. Fig.36 When the substrate structure 210 is a SOI (Silicon-On-Insulator) substrate, the buried oxide layer serves as the second sub-substrate 213. The top silicon layer serves as the second substrate 212. The back substrate serves as the first sub-substrate 214. When the substrate structure 210 is a SOI (Silicon-On-Insulator) substrate, the buried oxide layer serves as the second sub-substrate 213. The top silicon layer serves as the second substrate 212. The back substrate serves as the first sub-substrate 214.

[0171] The reverse side of the first sub-substrate 214 is subjected to D-RIE deep silicon etching to form a first sub-through hole 2011 to release the actuating structure.

[0172] Continue to refer Fig. 20 , by means of ICP, the second sub-substrate is further etched to form a second sub-through hole to completely release the actuating structure.

[0173] Optionally, the material of the support layer includes a high molecular polymer, and the material of the sacrificial layer includes a positive photoresist.

[0174] Specifically, the material of the support layer includes a high molecular polymer, which is convenient for the production of the support layer and can also reduce the production cost of the support layer. The material of the sacrificial layer includes a positive photoresist, which is convenient for the production of the sacrificial layer and can also reduce the production cost of the sacrificial layer, and can also facilitate the removal of the sacrificial layer later. The material of the support layer can specifically be a negative photoresist, so that when the sacrificial layer is removed, the structure of the support layer will not be affected.

[0175] Optional, Fig.37 is a schematic diagram of another actuation structure provided according to an embodiment of the present invention, with reference to Fig.37 The actuation structure provided in this embodiment further includes an exposed first pad 280 and a second pad 290 ; the first pad 280 is electrically connected to the first electrode 220 , and the second pad 290 is electrically connected to the second electrode 240 .

[0176] Specifically, the first pad 280 and the second pad 290 may be electrically connected to an external device, and may transmit an electrical signal transmitted by the external device to the first electrode 220 and the second electrode 240 .

[0177] Optionally, the thickness of the support layer ranges from 50 μm to 150 μm.

[0178] Specifically, when the MEMS speaker receives a driving signal, the piezoelectric film layer is deformed and transmitted from the support layer to the hard diaphragm layer. The thickness of the support layer is set to 50μm to 150μm, which can increase the vertical vibration range of the hard diaphragm layer, thereby greatly improving the SPL output by the MEMS speaker.

[0179] Optionally, a vertical projection of the second slit on the second substrate covers the first slit; and a vertical projection of the third slit on the second substrate covers a vertical projection of the second slit on the second substrate.

[0180] Specifically, in the process of manufacturing a MEMS speaker, the third slit may be formed first, and then the first electrode may be etched in the third slit to form the second slit, and then the second substrate may be etched in the second slit to form the first slit. The vertical projection of the second slit on the second substrate is set to cover the first slit; the vertical projection of the third slit on the second substrate covers the vertical projection of the second slit on the second substrate, which can facilitate the manufacturing of the second slit and the first slit.

[0181] In the same direction, the size of the third slit can be greater than or equal to the size of the second slit, and the size of the second slit can be greater than or equal to the size of the first slit. Setting the size of the third slit larger than the size of the second slit can allow a certain distance between the first electrode and the second electrode to avoid short circuit between the first electrode and the second electrode.

[0182] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0183] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for manufacturing a micro-electromechanical system loudspeaker, characterized in that: include: An actuating structure is formed, wherein the actuating structure comprises a substrate structure, a first electrode located at one side of the substrate structure, a piezoelectric film layer located at a side of the first electrode away from the substrate structure, and a second electrode located at a side of the piezoelectric film layer away from the first electrode; the substrate structure comprises a first substrate and a second substrate stacked in layers; the second substrate is located between the first substrate and the first electrode; the second substrate comprises a plurality of first slits; the first electrode comprises a plurality of second slits, the piezoelectric film layer comprises a plurality of third slits, and the third slits, the second slits and the first slits are connected; A support layer is formed on a side of the piezoelectric film layer away from the first electrode, wherein the support layer comprises a support ring and a support column, the support ring is located at the edge of the piezoelectric film layer, and the support ring is arranged around the support column; A sacrificial layer is formed on a side of the second electrode away from the piezoelectric film layer, wherein the sacrificial layer exposes the support layer and fills the gap between the support ring and the support column; the sacrificial layer includes a first groove structure; A hard diaphragm layer is formed on a side of the sacrificial layer away from the second electrode, wherein the hard diaphragm layer covers the support layer and the sacrificial layer, the hard diaphragm layer includes a bent structure and a planar structure, and a vertical projection of the bent structure on the second substrate overlaps with a vertical projection of the first groove structure on the second substrate; forming a first through hole in the first substrate, wherein the first through hole is connected to the first slit; The sacrificial layer is removed.

2. The method for manufacturing a MEMS speaker according to claim 1, characterized in that: The forming of a sacrificial layer on a side of the second electrode away from the piezoelectric film layer comprises: A first sacrificial transition layer is formed on a side of the second electrode away from the piezoelectric film layer; wherein the first sacrificial transition layer covers the support layer and fills the gap between the support ring and the support column; Processing the first sacrificial transition layer so that the processed first sacrificial transition layer exposes the support layer; forming a first mask layer on a side of the processed first sacrificial transition layer away from the second electrode; wherein the first mask layer covers the support layer and the processed first sacrificial transition layer; forming a second sacrificial transition layer on a side of the first mask layer away from the piezoelectric film layer; Processing the second sacrificial transition layer so that the processed second sacrificial transition layer includes a first through-hole structure; wherein the first through-hole structure exposes at least a portion of the first mask layer; The first mask layer is processed using the processed second sacrificial transition layer as a mask, so that the processed first mask layer includes a second through-hole structure; wherein the second through-hole structure exposes at least a portion of the processed first sacrificial transition layer; At the same time, etching the processed second sacrificial transition layer and the first sacrificial transition layer exposed by the first mask layer until the second sacrificial transition layer is completely etched to form the sacrificial layer; The remaining first mask layer is removed.

3. The method for manufacturing a MEMS speaker according to claim 1 or 2, characterized in that: The first groove structure includes a first groove substructure and a plurality of second groove substructures; The first groove substructure is adjacent to the support ring and surrounds one side of the support ring close to the support column; The vertical projections of the plurality of second groove substructures on the substrate structure surround the vertical projection of the support column on the substrate structure, and the vertical projections of the plurality of second groove substructures on the substrate structure are distributed in a whirlwind manner.

4. The method for manufacturing a MEMS speaker according to claim 1, characterized in that: The forming of the actuation structure comprises: Providing a substrate transition structure, wherein the substrate transition structure comprises the first substrate and the second transition substrate which are stacked; A first electrode transition layer and a piezoelectric film transition layer are formed on a side of the second transition substrate away from the first substrate; wherein the first electrode transition layer covers the second transition substrate; and the piezoelectric film transition layer covers the first electrode transition layer; Processing the piezoelectric film transition layer to form the piezoelectric film layer; forming the second electrode on a side of the piezoelectric film layer away from the first electrode transition layer; Processing the first electrode transition layer to form the first electrode; The second transition substrate is processed to form the second substrate to form the actuation structure.

5. The method for manufacturing a MEMS speaker according to claim 1, characterized in that: The hard diaphragm layer is formed on a side of the sacrificial layer away from the second electrode, comprising: The hard diaphragm layer is formed on a side of the sacrificial layer away from the second electrode by using an evaporation process.

6. The method for manufacturing a MEMS speaker according to claim 1, characterized in that: The first substrate includes a first sub-substrate and a second sub-substrate which are stacked, and the second sub-substrate is located between the first sub-substrate and the second substrate; The forming of a first through hole in the first substrate comprises: A first sub-through hole is formed in the first sub-substrate; A second sub-through hole is formed in the second sub-substrate, wherein the first sub-through hole and the second sub-through hole constitute the first through hole.

7. The method for manufacturing a MEMS speaker according to claim 1, characterized in that: The material of the support layer includes a high molecular polymer; The material of the sacrificial layer includes positive photoresist.

8. The method for manufacturing a MEMS speaker according to claim 1, characterized in that: The actuation structure further includes an exposed first pad and a second pad; the first pad is electrically connected to the first electrode, and the second pad is electrically connected to the second electrode.

9. The method for manufacturing a MEMS speaker according to claim 1, characterized in that: The thickness of the support layer ranges from 50 μm to 150 μm.

10. The method for manufacturing a MEMS speaker according to claim 1, characterized in that: The vertical projection of the second slit on the second substrate covers the first slit; A vertical projection of the third slit on the second substrate covers a vertical projection of the second slit on the second substrate.

Images