Method for manufacturing micro-speaker and micro-speaker

Abstract

The application provides a micro-speaker manufacturing method and a micro-speaker. The method comprises the following steps: first, providing a first substrate, the first substrate comprising a first surface and a second surface arranged oppositely; then, forming a first piezoelectric structure on the first surface; etching the first piezoelectric structure to form a first driving structure; then, forming a patterned mask on the second surface; then, using the patterned mask as a mask, performing back cavity etching on the second surface of the first substrate to form at least two air cavities and at least one vibration connecting rod; and finally, forming a sealing film layer on the second surface of the first substrate. The method makes the first driving structure deform after receiving a driving signal, drives the sealing film layer to vibrate through the vibration connecting rod, and thus pushes the air to make sound, thereby reducing the acoustic loss caused by the gap of the unsealed first driving structure, and further solving the problem that the performance is low due to the large acoustic loss of the micro-speaker in the prior art.

Description

Technical Field

[0001] This application relates to the field of MEMS microspeakers, and more specifically, to a method for fabricating a microspeaker and the microspeaker itself. Background Technology

[0002] With the rapid development of micro-electro-mechanical systems (MEMS), microspeakers have attracted increasing attention due to their advantages of small size, low power consumption, mass production, and integration with CMOS (Complementary Metal Oxide Semiconductor) technology. To date, MEMS speakers have primarily been used in in-ear applications, such as hearing aids and in-ear headphones. Classified by driving method, microspeakers are mainly divided into electrodynamic MEMS speakers, electrostatic MEMS speakers, piezoelectric MEMS speakers, and thermoelectric MEMS speakers. Among them, piezoelectric actuation offers advantages such as low driving voltage and high braking force. Piezoelectric MEMS speakers mainly consist of a piezoelectric diaphragm and an acoustic cavity. Due to the complexity of the diaphragm's vibration modes and limited braking space, achieving high sound pressure level (SPL) output and a flat frequency response is a significant design challenge.

[0003] The output sound pressure level (SPL) and sensitivity of a MEMS loudspeaker are directly determined by the frequency, area, and displacement of its diaphragm. Increasing the out-of-plane displacement of the piezoelectric diaphragm is an effective way to improve SPL, especially at low frequencies, because a larger displacement is needed at low frequencies to achieve the same SPL at high frequencies. Existing technologies include designing the diaphragm as a cantilever beam structure and a spring-braking structure, both of which use an unsealed vibrating diaphragm to achieve large diaphragm displacement. However, the gap structure of such unsealed diaphragms will cause acoustic losses, especially during actual manufacturing, which will produce greater acoustic errors. This problem can be solved by adding a sealed vibrating diaphragm layer on the unsealed driving diaphragm, where there is a cavity between the driving diaphragm and the sealed vibrating diaphragm. However, this will create assembly problems, requiring the integration of an additional diaphragm into the original loudspeaker, which cannot be done using semiconductor processes, resulting in high manufacturing complexity, difficulty in mass production, and the potential for irreversible damage to the properties of existing driving structure materials during manufacturing.

[0004] The information disclosed above in the background section is only intended to enhance the understanding of the background art of the art described herein. Therefore, the background art may contain certain information that does not constitute prior art known to those skilled in the art in this country. Summary of the Invention

[0005] The main objective of this application is to provide a method for fabricating a micro-speaker and a micro-speaker in order to solve the problem that the micro-speakers in the prior art have high acoustic loss and therefore low performance.

[0006] To achieve the above objectives, according to one aspect of this application, a method for fabricating a micro loudspeaker is provided, comprising: providing a first substrate, the first substrate including a first surface and a second surface disposed opposite to each other; forming a first piezoelectric structure on the first surface; etching the first piezoelectric structure to form a first driving structure; forming a mask on the second surface and patterning the mask to obtain a patterned mask; using the patterned mask as a mask, performing back cavity etching on the second surface of the first substrate to expose a portion of the surface of the first driving structure, and peeling off the remaining patterned mask to form at least two air cavities and at least one vibration link, one of the vibration links being disposed between two adjacent air cavities; forming a sealing film layer on the second surface of the first substrate, the sealing film layer closing the openings of the air cavities away from the first driving structure, wherein the first driving structure, upon receiving a driving signal, drives the vibration link and the sealing film layer to vibrate up and down.

[0007] Further, the sealing film layer includes a vibrating soft film. Applying the driving signal to the first driving structure, the first driving structure drives the vibrating link and the vibrating soft film to vibrate up and down, forming a sealing film layer on the second surface of the first substrate, includes: providing a second substrate, forming the vibrating soft film on the surface of the second substrate; using micro-transfer technology to transfer the vibrating soft film and the second substrate to the second surface of the first substrate, so that the vibrating link is connected to the vibrating soft film; peeling off the second substrate, wherein the vibrating soft film constitutes the sealing film layer.

[0008] Furthermore, the material of the vibrating diaphragm includes at least one of polymer materials, metal materials, biological diaphragm materials, and composite diaphragm materials.

[0009] Further, the sealing film layer includes a second piezoelectric structure. Applying the driving signal to the first driving structure and the second piezoelectric structure, the first driving structure and the second piezoelectric structure drive the vibrating link to vibrate up and down, forming a sealing film layer on the second surface of the first substrate, includes: providing a third substrate, forming the second piezoelectric structure on the surface of the third substrate; forming a first bonding layer on the second surface of the first substrate; forming a second bonding layer on the surface of the second piezoelectric structure away from the third substrate; bonding the first bonding layer and the second bonding layer, and peeling off the third substrate, wherein the second piezoelectric structure constitutes the sealing film layer.

[0010] Furthermore, one vibration link is provided, which is located at the center of the first driving structure, or multiple vibration links are provided, which are distributed around the first driving structure. The shape of the predetermined cross-section of the vibration link is at least one of a circle, a square, and an annular shape, and the predetermined cross-section is a cross-section perpendicular to the thickness direction of the first substrate.

[0011] According to another aspect of this application, a micro loudspeaker is provided, fabricated using any of the micro loudspeaker fabrication methods described above, comprising a first substrate, a first driving structure, at least two air cavities, and a sealing film layer, wherein the first substrate includes a first surface and a second surface disposed opposite to each other; the first driving structure is located on the first surface of the first substrate; at least two air cavities are located in the first substrate, the air cavities forming at least one vibration link on the first substrate, one vibration link being disposed between two adjacent air cavities; the sealing film layer is located on the second surface of the first substrate, the sealing film layer closing the openings of the air cavities away from the first driving structure, and the first driving structure, upon receiving a driving signal, drives the vibration link and the sealing film layer to vibrate up and down.

[0012] Furthermore, the sealing film layer includes a vibrating soft membrane, and the driving signal is applied to the first driving structure, which drives the vibrating connecting rod and the vibrating soft membrane to vibrate up and down; the sealing film layer includes a second piezoelectric structure, and the driving signal is applied to the first driving structure and the second piezoelectric structure, which drive the vibrating connecting rod to vibrate up and down.

[0013] Furthermore, the material of the vibrating diaphragm includes at least one of polymer materials, metal materials, biological diaphragm materials, and composite diaphragm materials.

[0014] Furthermore, one vibration link is provided, which is located at the center of the first driving structure, or multiple vibration links are provided, which are distributed around the first driving structure. The shape of the predetermined cross-section of the vibration link is at least one of a circle, a square, and an annular shape, and the predetermined cross-section is a cross-section perpendicular to the thickness direction of the first substrate.

[0015] Furthermore, the micro-speaker is connected to the fixed boundary via anchor points.

[0016] According to the technical solution of this application, in the method for fabricating the micro loudspeaker, firstly, a first substrate is provided, the first substrate including a first surface and a second surface disposed opposite to each other; then, a first piezoelectric structure is formed on the first surface; the first piezoelectric structure is etched to form a first driving structure; then, a mask is formed on the second surface, and the mask is patterned to obtain a patterned mask; then, using the patterned mask as a mask, the second surface of the first substrate is etched with a back cavity, exposing part of the surface of the first piezoelectric structure, and the remaining patterned mask is peeled off to form at least two air cavities and at least one vibration link, one of the vibration links being disposed between two adjacent air cavities; finally, a sealing film layer is formed on the second surface of the first substrate, the sealing film layer closing the openings of the air cavities away from the first piezoelectric structure, and the first driving structure, upon receiving a driving signal, drives the vibration link and the sealing film layer to vibrate up and down. The method forms a first driving structure on a first surface of a first substrate and a sealing film layer on a second surface. The first driving structure and the sealing film layer are connected by a vibration link, and an air cavity is formed in the area around the vibration link between the first driving structure and the sealing film layer. The first driving structure receives a driving signal and deforms, driving the sealing film layer to vibrate through the vibration link, thereby pushing the air to produce sound. This reduces the acoustic loss caused by the gap of the unsealed first driving structure, and thus solves the problem of large acoustic loss and low performance of micro loudspeakers in the prior art. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0018] Figure 1 A flowchart illustrating a method for fabricating a micro-speaker according to an embodiment of this application is shown;

[0019] Figure 2 A side view of the structure after forming the first piezoelectric structure according to an embodiment of this application is shown;

[0020] Figure 3 A side view of the structure after forming the first drive structure according to an embodiment of this application is shown;

[0021] Figure 4 A side view of the structure after forming a patterned photoresist layer according to an embodiment of this application is shown;

[0022] Figure 5A side view of the structure after forming an air cavity according to an embodiment of this application is shown;

[0023] Figure 6 A side view of the structure after forming a patterned photoresist layer according to another embodiment of this application is shown;

[0024] Figure 7 A side view of the structure after forming an air cavity according to another embodiment of this application is shown;

[0025] Figure 8 A side view of a structure in which a vibrating diaphragm is formed on the surface of a second substrate according to an embodiment of this application is shown.

[0026] Figure 9 A side view of the structure after bonding a first substrate and a vibrating soft film according to an embodiment of this application is shown;

[0027] Figure 10 A structural side view of a microspeaker according to an embodiment of this application is shown;

[0028] Figure 11 A side view of a structure in which a second piezoelectric structure is formed on the surface of a third substrate according to an embodiment of this application is shown;

[0029] Figure 12 A side view of the structure after a first bonding layer has been formed on the surface of a first substrate according to another embodiment of this application is shown;

[0030] Figure 13 A side view of the structure after forming a second bonding layer on the surface of a third substrate, according to another embodiment of this application, is shown.

[0031] Figure 14 A side view of the structure after the first bonding layer and the second bonding layer are bonded according to an embodiment of this application is shown;

[0032] Figure 15 A structural side view of a microspeaker according to another embodiment of this application is shown.

[0033] The above figures include the following reference numerals:

[0034] 101. First substrate; 102. Air cavity; 103. Vibrating link; 201. First piezoelectric structure; 202. Slit structure; 203. First driving structure; 204. Piezoelectric structure part; 211. First electrode layer; 212. First piezoelectric layer; 213. Second electrode layer; 214. Second piezoelectric layer; 215. Third electrode layer; 301. Photomask; 302. Patterned photoresist layer; 401. Second substrate; 402. Vibrating soft film; 501. Third substrate; 502. Second piezoelectric structure; 503. First bonding layer; 504. Second bonding layer; 505. Bonding layer. Detailed Implementation

[0035] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0036] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0037] It should be understood that when an element (such as a layer, film, region, or substrate) is described as being "on" another element, the element may be directly on the other element, or there may be an intermediate element present. Furthermore, in the specification and claims, when an element is described as being "connected" to another element, the element may be "directly connected" to the other element, or "connected" to the other element via a third element.

[0038] As described in the background section, existing microspeakers suffer from high acoustic loss, resulting in low performance. To address this issue, this application proposes a method for fabricating a microspeaker and the microspeaker itself.

[0039] According to an embodiment of this application, a method for fabricating a micro loudspeaker is provided.

[0040] Figure 1 This is a flowchart of a method for fabricating a micro-speaker according to an embodiment of this application. Figure 1 As shown, the method includes the following steps:

[0041] Step S101, as follows Figure 2 As shown, a first substrate 101 is provided, the first substrate 101 including a first surface and a second surface disposed opposite to each other;

[0042] Step S102, as follows Figure 2 As shown, a first piezoelectric structure 201 is formed on the first surface described above;

[0043] Step S103, as follows Figure 2 and Figure 3 As shown, the first piezoelectric structure 201 is etched to form the first driving structure 203;

[0044] Step S104, as follows Figure 4 As shown, a mask 301 is formed on the second surface, and the mask is patterned to obtain a patterned mask.

[0045] Step S105, as follows Figure 4 and Figure 5 As shown, using the patterned mask as a mask, the second surface of the first substrate 101 is etched with a back cavity, exposing part of the surface of the first driving structure 203, and peeling off the remaining patterned mask to form at least two air cavities 102 and at least one vibration link 103, with one vibration link 103 disposed between two adjacent air cavities 102.

[0046] Step S106, as follows Figure 10 As shown, a sealing film layer is formed on the second surface of the first substrate 101. The sealing film layer closes the opening of the air cavity 102 away from the first drive structure 203. When the first drive structure 203 receives a drive signal, it drives the vibration link 103 and the sealing film layer to vibrate up and down.

[0047] In the above-described method for fabricating a micro loudspeaker, firstly, a first substrate is provided, the first substrate including a first surface and a second surface disposed opposite to each other; then, a first piezoelectric structure is formed on the first surface; the first piezoelectric structure is etched to form a first driving structure; then, a mask is formed on the second surface, and the mask is patterned to obtain a patterned mask; then, using the patterned mask as a mask, back cavity etching is performed on the second surface of the first substrate, exposing part of the surface of the first piezoelectric structure, and the remaining patterned mask is peeled off to form at least two air cavities and at least one vibration link, one of the vibration links being disposed between two adjacent air cavities; finally, a sealing film layer is formed on the second surface of the first substrate, the sealing film layer closing the openings of the air cavities away from the first piezoelectric structure, and the first driving structure, upon receiving a driving signal, drives the vibration link and the sealing film layer to vibrate up and down. The method forms a first driving structure on a first surface of a first substrate and a sealing film layer on a second surface. The first driving structure and the sealing film layer are connected by a vibration link, and an air cavity is formed in the area around the vibration link between the first driving structure and the sealing film layer. The first driving structure receives a driving signal and deforms, driving the sealing film layer to vibrate through the vibration link, thereby pushing the air to produce sound. This reduces the acoustic loss caused by the gap of the unsealed first driving structure, and thus solves the problem of large acoustic loss and low performance of micro loudspeakers in the prior art.

[0048] In practical applications, when the micro loudspeaker is working, the air cavity mentioned above is also the acoustic cavity. Due to the deformation and vibration caused by the first driving structure receiving the driving signal, the air in the acoustic cavity will expand or compress. This acoustic cavity can achieve a tuning effect with the other acoustic cavities formed by the encapsulation structure.

[0049] In one specific embodiment of this application, a first piezoelectric structure is formed on the aforementioned first surface, including: as follows Figure 2 As shown, a first electrode layer 211, a first piezoelectric layer 212, a second electrode layer 213, a second piezoelectric layer 214, and a third electrode layer 215 are sequentially stacked on the first surface of the first substrate 101. These three layers constitute the first piezoelectric structure 201. The more conductive layers in the first piezoelectric structure, the higher the Q value of the microspeaker. However, the more conductive layers, the more complex the fabrication process. Therefore, using a stack of three electrode layers and two piezoelectric layers can improve the Q value of the microspeaker without complicating the fabrication process.

[0050] In order to increase the amplitude of the vertical vibration of the first electrode structure when it receives a driving signal, thereby increasing the sound pressure level, in another specific embodiment of this application, the first piezoelectric structure is etched to form a first driving structure, which is similar to a spring structure. When the first driving structure receives a driving signal and is in working state, the first driving structure can vibrate up and down to make piston motion.

[0051] Specifically, the shape of the aforementioned gap structure can be manufactured according to the actual situation.

[0052] In another specific embodiment of this application, a mask is formed on the second surface, and the mask is patterned to obtain a patterned mask, including: Figure 4 As shown, a photomask 301 is formed on the second surface of the first substrate 101; a patterned photoresist layer 302 is formed on the surface of the photomask 301 away from the first substrate 101. Using the patterned photomask as a mask, back cavity etching is performed on the second surface of the first substrate, including: Figure 4 and Figure 5 As shown, using the patterned photoresist layer 302 as a mask, the mask 301 and the first substrate 101 are etched to form at least two air cavities 102 and at least one vibration link 103; the remaining patterned photoresist layer 302 and the remaining mask 301 are then removed. A mask is formed on the first surface of the first substrate to protect the first substrate from damage during etching. The mask and the first substrate are etched through openings formed by the patterned photoresist layer to form air cavities.

[0053] In order to improve the etching resistance and planarization properties of the photomask, in another embodiment of this application, the material of the photomask includes at least one of silicon oxide, silicon nitride, silicon carbide or metal nitride.

[0054] While etching the first substrate to form an air cavity, a vibration linkage is formed on a portion of the sidewall of the air cavity. In another embodiment of this application, such as... Figure 5 As shown, one vibration link is provided, and the vibration link 103 is located at the center of the first driving structure 203, as shown. Figure 7 As shown, or multiple vibration links 103 are provided, and multiple vibration links are distributed around the first driving structure 203. The shape of the predetermined cross section of the vibration link 103 is at least one of a circle, a square, and an annular shape, and the predetermined cross section is a cross section perpendicular to the thickness direction of the first substrate.

[0055] Specifically, if a vibration link is formed and its position is located at the center of the first driving structure, the point displacement of the vibration link can reach its maximum, that is, the vibration point displacement of the subsequently manufactured sealing membrane can be maximized. In another specific embodiment of this application, forming the above-mentioned vibration link includes: Figure 4 As shown, the patterned photoresist layer 302 is formed on the surface of the photomask 301 away from the first substrate 101, such that the first substrate 101 on the surface of the piezoelectric structure portion 204 and the first substrate 101 on the surface of the first region of the first driving structure 203 are covered by the patterned photoresist layer 302, and the projection of the first region onto the first substrate 101 is located at the center of the projection of the first driving structure 203 onto the first substrate 101; as Figure 4 and Figure 5 As shown, using the patterned photoresist layer 302 as a mask, the mask 301 and the first substrate 101 are etched to form the air cavity 102, and the first substrate 101 located on the surface of the first region forms a vibration link 103.

[0056] In another specific embodiment of this application, forming the above-mentioned vibration link includes: as follows Figure 6 As shown, the patterned photoresist layer 302 is formed on the surface of the photomask 301 away from the first substrate 101, such that the first substrate 101 on the surface of the piezoelectric structure portion 204 and the first substrate 101 on the surfaces of the plurality of second regions of the first driving structure 203 are covered by the patterned photoresist layer 302. The projections of the plurality of second regions onto the first substrate 101 are located at the edge positions of the projections of the first driving structure 203 onto the first substrate 101, and the plurality of second regions are arranged in a spaced-around pattern. Figure 6 and Figure 7 As shown, using the patterned photoresist layer 302 as a mask, the mask 301 and the first substrate 101 are etched to form the air cavity 102. A plurality of vibration links 103 are formed on the surfaces of the multiple second regions of the first substrate 101, corresponding to each other. Multiple vibration links are formed at the periphery of the first driving structure. The volume of air propelled during vibration differs between vibration links formed at the periphery and those formed at the center, resulting in different stress distributions in the subsequently fabricated sealing diaphragm. Different link positions, numbers, and shapes all affect the acoustic performance of the micro-speaker, and those skilled in the art can adjust these settings according to actual conditions.

[0057] In practical applications, when there are multiple vibration links, the first driving structure in contact with the vibration link can be patterned according to the position of the link, so that the vibration amplitude of each link and the stress distribution of the corresponding sealing membrane are more uniform.

[0058] To form the acoustic cavity of the micro-speaker, the side of the air cavity in the first substrate away from the first driving structure needs to be sealed. In another embodiment of this application, the sealing film layer includes a vibrating diaphragm. An electrical signal is applied to the first driving structure, which drives the vibrating link and the vibrating diaphragm to vibrate up and down, forming a sealing film layer on the second surface of the first substrate, including: Figure 8 As shown, a second substrate 401 is provided, and the aforementioned vibrating soft film 402 is formed on the surface of the second substrate 401; as Figure 9 As shown, the vibrating soft film 402 and the second substrate 401 are transferred to the second surface of the first substrate 101 using micro-transfer printing technology, thereby connecting the vibrating link 103 to the vibrating soft film 402; Figure 9 and Figure 10 As shown, after peeling off the second substrate 401, the vibrating soft membrane 402 constitutes the sealing film layer.

[0059] Specifically, micro-transfer technology includes motion-controlled transfer, thermal transfer, water-assisted transfer, laser-assisted transfer, and transfer based on shape memory polymers. The principle is to use an elastic stamp combined with a high-precision motion-controlled printhead to selectively pick up a large array of micro-devices and print (place) them on a substrate. The above embodiments can conveniently and quickly produce sealing soft films through micro-transfer technology.

[0060] In practical applications, the material of the second substrate includes at least one of polydimethylsiloxane, polyvinyl alcohol, and shape memory alloy. All of these materials are suitable for microtransfer printing technology.

[0061] In order to enable the sealing membrane layer to vibrate in sync with the vibrating link, in another embodiment of this application, the material of the vibrating membrane includes at least one of polymer materials, metal materials, biological diaphragm materials, and composite diaphragm materials.

[0062] In another embodiment of this application, the sealing film layer includes a second piezoelectric structure. An electrical signal is applied to the first driving structure and the second piezoelectric structure, causing the first driving structure and the second piezoelectric structure to drive the vibrating link to vibrate up and down, forming a sealing film layer on the second surface of the first substrate, including: Figure 11 As shown, a third substrate 501 is provided, and the second piezoelectric structure 502 is formed on the surface of the third substrate 501; as Figure 12 As shown, a first bonding layer 503 is formed on the second surface of the first substrate 101; as Figure 13 As shown, a second bonding layer 504 is formed on the surface of the second piezoelectric structure 502 that is away from the third substrate 501; as Figure 14 and Figure 15 As shown, the first bonding layer 503 and the second bonding layer 504 are bonded to form a bonding layer 505, and the third substrate 501 is peeled off. The second piezoelectric structure 502 constitutes the sealing film layer. By using the second piezoelectric structure as the sealing film layer, a dual-drive mode can be achieved. The drive signal can drive both the unsealed first drive structure and the second piezoelectric structure to vibrate simultaneously. When piezoelectric drive is used, both the first drive structure and the second piezoelectric structure deform due to the inverse piezoelectric effect. The out-of-plane displacement of the second piezoelectric structure includes both its own deformation displacement and the drive displacement transmitted by the first drive structure through the connecting rod. Therefore, the out-of-plane displacement of the sealing film layer increases, thereby further improving the sound pressure level of the micro-speaker.

[0063] In order to enable the first bonding layer and the second bonding layer to be easily bonded together without affecting the performance of the micro loudspeaker, in another specific embodiment of this application, the material of the dielectric layer includes at least one of gold, aluminum and copper.

[0064] According to another aspect of this application, a micro-speaker is provided, manufactured using any of the above-described micro-speaker fabrication methods, such as... Figure 10 or Figure 15 As shown, the device includes a first substrate 101, a first driving structure 203, at least two air cavities 102, and a sealing film layer. The first substrate 101 includes a first surface and a second surface disposed opposite to each other. The first driving structure 203 is located on the first surface of the first substrate 101. At least two air cavities 102 are located in the first substrate 101, and the air cavities 102 cause the first substrate 101 to form at least one vibration link 103, with one vibration link 103 disposed between two adjacent air cavities 102. The sealing film layer is located on the second surface of the first substrate 101, and the sealing film layer closes the openings of the air cavities away from the first driving structure.

[0065] The aforementioned micro-speaker, fabricated using any of the aforementioned micro-speaker manufacturing methods, includes a first substrate, a first driving structure, at least two air cavities, and a sealing film layer. The first substrate includes a first surface and a second surface disposed opposite to each other. The first driving structure is located on the first surface of the substrate. At least two air cavities are located within the substrate, forming at least one vibration link between adjacent air cavities. The sealing film layer is located on the second surface of the first substrate, sealing the openings of the air cavities away from the first driving structure. The first driving structure is formed on the first surface of the first substrate of this micro-speaker, and a sealing film layer is formed on the second surface. The first driving structure and the sealing film layer are connected by the vibration link, and an air cavity is formed in the area around the vibration link between the first driving structure and the sealing film layer. The first driving structure receives a driving signal and deforms, driving the sealing film layer to vibrate through the vibration link, thereby pushing air to produce sound. This reduces acoustic loss caused by gaps in the unsealed first driving structure, thus solving the problem of high acoustic loss and low performance in existing micro-speakers.

[0066] In another embodiment of this application, such as Figure 10 As shown, the sealing membrane layer includes a vibrating diaphragm 402. An electrical signal is applied to the first driving structure 203, causing the first driving structure 203 to drive the vibrating connecting rod 103 and the vibrating diaphragm 402 to vibrate up and down. Figure 15 As shown, the sealing film layer includes a second piezoelectric structure 502. An electrical signal is applied to the first driving structure 203 and the second piezoelectric structure 502, and the first driving structure 203 and the second piezoelectric structure 502 drive the vibration link 103 to vibrate up and down.

[0067] In order to enable the sealing membrane layer to vibrate in sync with the vibrating link, in another embodiment of this application, the material of the vibrating membrane includes at least one of polymer materials, metal materials, biological diaphragm materials, and composite diaphragm materials.

[0068] In another embodiment of this application, such as Figure 5 As shown, one vibration link is provided, and the vibration link 103 is located at the center of the first driving structure 203, as shown. Figure 7As shown, multiple vibration links 103 may be provided, distributed around the perimeter of the first driving structure 203. The predetermined cross-sectional shape of each vibration link 103 is at least one of a circle, a square, or an annular shape, and the predetermined cross-section is perpendicular to the thickness direction of the first substrate. When a single vibration link is formed and its position is at the center of the first driving structure, the point displacement of the vibration link can reach its maximum, thus maximizing the vibration point displacement of the subsequently manufactured sealing diaphragm. Forming multiple vibration links at the perimeter of the first driving structure results in different air volumes being propelled during vibration compared to forming them at the center, leading to different stress distributions in the subsequently manufactured sealing diaphragm. Different link positions, numbers, and shapes all affect the acoustic performance of the micro-speaker, and those skilled in the art can adjust the settings according to actual conditions.

[0069] In another embodiment of this application, the micro-speaker is connected to a fixed boundary via anchor points. Connecting to the fixed boundary via anchor points allows the first driving structure to vibrate vertically.

[0070] To enable those skilled in the art to better understand the technical solution of this application, the technical solution of this application will be described in detail below with reference to specific embodiments.

[0071] Example 1

[0072] The fabrication method of the micro-speaker in this embodiment includes the following process:

[0073] First, such as Figure 2 As shown, a first substrate 101 is provided, the first substrate 101 including a first surface and a second surface disposed opposite to each other;

[0074] Subsequently, a first piezoelectric structure 201 is formed on the aforementioned first surface, specifically including: such as Figure 2 As shown, a first electrode layer 211, a first piezoelectric layer 212, a second electrode layer 213, a second piezoelectric layer 214, and a third electrode layer 215 are formed sequentially on the first surface of the first substrate 101. The first electrode layer 211, the first piezoelectric layer 212, the second electrode layer 213, the second piezoelectric layer 214, and the third electrode layer 215 constitute the first piezoelectric structure 201.

[0075] After that, as Figure 3 As shown, the first piezoelectric structure 201 is etched to form the first driving structure 203. Specifically, this includes: Figure 2 and Figure 3As shown, the first piezoelectric structure 201 is graphically represented to form a plurality of slit structures 202, such that the first piezoelectric structure 201 is divided into a first driving structure 203 and a piezoelectric structure portion 204 surrounding the first driving structure 203. Specifically, a portion of the first piezoelectric structure 201 is removed to form a plurality of slit structures 202 arranged at intervals, and the center line connecting the plurality of slit structures 202 forms a ring.

[0076] After that, as Figure 4 As shown, the patterned photoresist layer 302 is formed on the surface of the photomask 301 away from the first substrate 101, such that the first substrate 101 on the surface of the piezoelectric structure portion 204 and the first substrate 101 on the surface of the first region of the first driving structure 203 are covered by the patterned photoresist layer 302, and the projection of the first region onto the first substrate 101 is located at the center of the projection of the first driving structure 203 onto the first substrate 101; as Figure 4 and Figure 5 As shown, using the patterned photoresist layer 302 as a mask, the mask 301 and the first substrate 101 are etched to form the air cavity 102, and the first substrate 101 located on the surface of the first region forms a vibration link 103.

[0077] Finally, as Figure 10 As shown, a sealing film layer is formed on the second surface of the first substrate 101, specifically including: Figure 8 As shown, a second substrate 401 is provided, and the aforementioned vibrating soft film 402 is formed on the second substrate 401; as Figure 9 and Figure 10 As shown, the vibration soft film 402 is transferred to the second surface of the first substrate 101 using micro-transfer technology, so that the vibration link 103 is connected to the vibration soft film 402; after peeling off the second substrate 401, the vibration soft film 402 constitutes the sealing film layer.

[0078] Example 2

[0079] The fabrication method of the micro-speaker in this embodiment includes the following process:

[0080] First, such as Figure 2 As shown, a first substrate 101 is provided, the first substrate 101 including a first surface and a second surface disposed opposite to each other;

[0081] Subsequently, a first piezoelectric structure 201 is formed on the aforementioned first surface, specifically including: such as Figure 2As shown, a first electrode layer 211, a first piezoelectric layer 212, a second electrode layer 213, a second piezoelectric layer 214, and a third electrode layer 215 are formed sequentially on the first surface of the first substrate 101. The first electrode layer 211, the first piezoelectric layer 212, the second electrode layer 213, the second piezoelectric layer 214, and the third electrode layer 215 constitute the first piezoelectric structure 201.

[0082] After that, as Figure 3 As shown, the first piezoelectric structure 201 is etched to form the first driving structure 203. Specifically, this includes: Figure 2 and Figure 3 As shown, the first piezoelectric structure 201 is graphically represented to form a plurality of slit structures 202, such that the first piezoelectric structure 201 is divided into a first driving structure 203 and a piezoelectric structure portion 204 surrounding the first driving structure 203. Specifically, a portion of the first piezoelectric structure 201 is removed to form a plurality of slit structures 202 arranged at intervals, and the center line connecting the plurality of slit structures 202 forms a ring.

[0083] After that, as Figure 4 As shown, the patterned photoresist layer 302 is formed on the surface of the photomask 301 away from the first substrate 101, such that the first substrate 101 on the surface of the piezoelectric structure portion 204 and the first substrate 101 on the surface of the first region of the first driving structure 203 are covered by the patterned photoresist layer 302, and the projection of the first region onto the first substrate 101 is located at the center of the projection of the first driving structure 203 onto the first substrate 101; as Figure 4 and Figure 5 As shown, using the patterned photoresist layer 302 as a mask, the mask 301 and the first substrate 101 are etched to form the air cavity 102, and the first substrate 101 located on the surface of the first region forms a vibration link 103.

[0084] Finally, as Figure 15 As shown, a sealing film layer is formed on the second surface of the first substrate 101, specifically including: Figure 11 As shown, a third substrate 501 is provided, on which the second piezoelectric structure 502 is formed; as Figure 12 As shown, a first bonding layer 503 is formed on the second surface of the first substrate 101; as Figure 13 As shown, a second bonding layer 504 is formed on the surface of the second piezoelectric structure 502 that is away from the third substrate 501; as Figure 14 and Figure 15As shown, the first bonding layer 503 and the second bonding layer 504 are bonded to form a bonding layer 505, and the third substrate 501 is peeled off. The second piezoelectric structure 502 constitutes the sealing film layer.

[0085] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0086] As can be seen from the above description, the embodiments of this application achieve the following technical effects:

[0087] 1) In the above-described method for fabricating the micro loudspeaker of this application, firstly, a first substrate is provided, the first substrate including a first surface and a second surface disposed opposite to each other; then, a first piezoelectric structure is formed on the first surface; the first piezoelectric structure is etched to form a first driving structure; then, a mask is formed on the second surface, and the mask is patterned to obtain a patterned mask; then, using the patterned mask as a mask, back cavity etching is performed on the second surface of the first substrate, exposing part of the surface of the first piezoelectric structure, and the remaining patterned mask is peeled off to form at least two air cavities and at least one vibration link, one of the vibration links being disposed between two adjacent air cavities; finally, a sealing film layer is formed on the second surface of the first substrate, the sealing film layer closing the openings of the air cavities away from the first piezoelectric structure, and the first driving structure, upon receiving a driving signal, drives the vibration link and the sealing film layer to vibrate up and down. The method forms a first driving structure on a first surface of a first substrate and a sealing film layer on a second surface. The first driving structure and the sealing film layer are connected by a vibration link, and an air cavity is formed in the area around the vibration link between the first driving structure and the sealing film layer. The first driving structure receives a driving signal and deforms, driving the sealing film layer to vibrate through the vibration link, thereby pushing the air to produce sound. This reduces the acoustic loss caused by the gap of the unsealed first driving structure, and thus solves the problem of large acoustic loss and low performance of micro loudspeakers in the prior art.

[0088] 2) The aforementioned micro-speaker, fabricated using any of the aforementioned micro-speaker fabrication methods, includes a first substrate, a first driving structure, at least two air cavities, and a sealing film layer. The first substrate includes a first surface and a second surface disposed opposite to each other. The first driving structure is located on the first surface of the substrate. At least two air cavities are located within the substrate, forming at least one vibration link between the substrate and one vibration link disposed between two adjacent air cavities. The sealing film layer is located on the second surface of the first substrate, sealing the openings of the air cavities away from the first driving structure. The first surface of the first substrate of this micro-speaker has the first driving structure formed, and the second surface has the sealing film layer formed. The first driving structure and the sealing film layer are connected by the vibration link, and an air cavity is formed in the area around the vibration link between the first driving structure and the sealing film layer. The first driving structure receives a driving signal and deforms, driving the sealing film layer to vibrate through the vibration link, thereby pushing air to produce sound. This reduces acoustic loss caused by gaps in the unsealed first driving structure, thus solving the problem of high acoustic loss and low performance in existing micro-speakers.

[0089] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for fabricating a micro loudspeaker, characterized in that, include: A first substrate is provided, the first substrate including a first surface and a second surface disposed opposite to each other; A first piezoelectric structure is formed on the first surface; The first piezoelectric structure is etched to form the first driving structure; A mask is formed on the second surface, and the mask is patterned to obtain a patterned mask. Using the patterned mask as a mask, the second surface of the first substrate is etched with a back cavity, exposing a portion of the surface of the first driving structure, and the remaining patterned mask is peeled off to form at least two air cavities and at least one vibration link, with one vibration link disposed between two adjacent air cavities. A sealing film layer is formed on the second surface of the first substrate, the sealing film layer closing the opening of the air cavity away from the first driving structure, and the first driving structure driving the vibration link and the sealing film layer to vibrate up and down when receiving a driving signal; The sealing film layer includes a vibrating diaphragm. A driving signal is applied to the first driving structure, causing the vibrating connecting rod and the vibrating diaphragm to vibrate up and down, forming a sealing film layer on the second surface of the first substrate. The sealing film layer includes: A second substrate is provided, and the vibrating diaphragm is formed on the surface of the second substrate; The vibrating soft film and the second substrate are transferred onto the second surface of the first substrate using micro-transfer technology, so that the vibrating link is connected to the vibrating soft film; After peeling off the second substrate, the vibrating diaphragm forms the sealing film layer; The sealing film layer includes a second piezoelectric structure. The driving signal is applied to the first driving structure and the second piezoelectric structure, causing the first driving structure and the second piezoelectric structure to drive the vibrating link to vibrate up and down, forming a sealing film layer on the second surface of the first substrate, comprising: A third substrate is provided, and the second piezoelectric structure is formed on the surface of the third substrate; A first bonding layer is formed on the second surface of the first substrate; A second bonding layer is formed on the surface of the second piezoelectric structure away from the third substrate; The first bonding layer and the second bonding layer are bonded together, and the third substrate is peeled off, wherein the second piezoelectric structure constitutes the sealing film layer.

2. The method for preparing a micro loudspeaker according to claim 1, characterized in that, The material of the vibrating diaphragm includes at least one of polymer materials, metal materials, biological diaphragm materials, and composite diaphragm materials.

3. The method for preparing a micro loudspeaker according to claim 1 or 2, characterized in that, One vibration link is provided, which is located at the center of the first driving structure, or multiple vibration links are provided, which are distributed around the first driving structure. The shape of the predetermined cross-section of the vibration link is at least one of a circle, a square, and an annular shape, and the predetermined cross-section is a cross-section perpendicular to the thickness direction of the first substrate.

4. A micro loudspeaker, characterized in that, The micro loudspeaker is manufactured using the method described in any one of claims 1 to 3, comprising: The first substrate includes a first surface and a second surface disposed opposite to each other; A first driving structure is located on the first surface of the first substrate; At least two air cavities are located in the first substrate, the air cavities causing the first substrate to form at least one vibration link, one of the vibration links being disposed between two adjacent air cavities; A sealing film layer is located on the second surface of the first substrate. The sealing film layer closes the opening of the air cavity away from the first drive structure. When the first drive structure receives a drive signal, it drives the vibration link and the sealing film layer to vibrate up and down.

5. The micro loudspeaker according to claim 4, characterized in that, The sealing membrane layer includes a vibrating membrane. When the driving signal is applied to the first driving structure, the first driving structure drives the vibrating connecting rod and the vibrating membrane to vibrate up and down. The sealing film layer includes a second piezoelectric structure. The driving signal is applied to the first driving structure and the second piezoelectric structure, and the first driving structure and the second piezoelectric structure drive the vibration link to vibrate up and down.

6. The micro loudspeaker according to claim 5, characterized in that, The material of the vibrating diaphragm includes at least one of polymer materials, metal materials, biological diaphragm materials, and composite diaphragm materials.

7. The micro loudspeaker according to claim 4, characterized in that, One vibration link is provided, which is located at the center of the first driving structure, or multiple vibration links are provided, which are distributed around the first driving structure. The shape of the predetermined cross-section of the vibration link is at least one of a circle, a square, and an annular shape, and the predetermined cross-section is a cross-section perpendicular to the thickness direction of the first substrate.

8. The micro loudspeaker according to claim 4, characterized in that, The micro-speaker is connected to a fixed boundary via anchor points.

Images