MEMS Acoustic Wave Transducer

Abstract

The present invention provides a micro-electromechanical system acoustic wave converter. The acoustic wave converter comprises a first plate, a spacer layer, and a second plate on the first plate and the spacer layer. The first plate comprises a carrier plate, a first substrate layer, and a first metal layer. The carrier plate has a first opening formed in a central area. The first substrate layer is located on the carrier plate and above the first opening. The first metal layer is located on the first substrate layer. The spacer layer is located on the first plate and surrounds the central area. The second plate comprises a second substrate layer, a second metal layer located on the spacer layer, and a plurality of second openings penetrating the second substrate layer and the second metal layer.

Description

Technical Field

[0001] The embodiment of the present invention relates to a micro-electromechanical system acoustic wave converter. Background Art

[0002] With the rapid development of the electronics and information industries, multimedia player devices are also becoming increasingly miniaturized and portable. For example, an electronic portable media player (PMP) or a digital audio player (DAP) is a portable electronic device that can store and play multimedia files. The above devices all require speakers to play sound, but the existing speaker structure and manufacturing technology are not conducive to integration into multimedia playback devices that need to be thin and short. In order to make up for this deficiency, the following technical means have been developed. Summary of the invention

[0003] One aspect of the present invention provides an acoustic wave converter. The acoustic wave converter includes a first plate, a spacer layer, and a second plate on the first plate and the spacer layer. The first plate includes a carrier plate, a first substrate layer, and a first metal layer. A first opening is formed in the central area of ​​the carrier plate. The first substrate layer is located on the carrier plate and above the first opening. The first metal layer is located on the first substrate layer. The spacer layer is located on the first plate and surrounds the central area. The second plate includes a second substrate layer, a second metal layer located on the spacer layer, and a plurality of second openings penetrating the second substrate layer and the second metal layer.

[0004] Another aspect of the present invention provides an acoustic wave converter module. The acoustic wave converter module includes a first acoustic wave converter, a first sealing wall, a top cover and a first signal processing unit. The first acoustic wave converter includes a first bottom plate, a first spacer layer and a first top plate. The first bottom plate includes a first glass layer, a first opening formed in the central area of ​​the first glass layer, a first substrate layer located on the first glass layer and above the first opening, and a first metal layer located on the first substrate layer. The first spacer layer is located on the first bottom plate and surrounds the central area of ​​the first glass layer. The first top plate has a plurality of second openings. The first top plate also includes a second substrate layer and a second metal layer located on the first spacer layer. The first sealing wall is located on the first bottom plate of the first acoustic wave converter. The top cover is located on the first sealing wall. The first signal processing circuit couples the first metal layer and the second metal layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Aspects of the present disclosure are best understood from the following detailed description read in conjunction with the accompanying drawings. It should be noted that, in accordance with standard industry practice, various components are not drawn to scale. In fact, the dimensions of various components may be arbitrarily increased or reduced for clarity of discussion.

[0006] Figure 1 is a flow chart of an embodiment of a method for forming a microelectromechanical (MEMS) microphone according to the present disclosure.

[0007] Figure 2A is a top view of an embodiment of a MEMS microphone at a manufacturing stage according to a method of forming a MEMS microphone disclosed herein, Figure 2B is along Figure 2A A cross-sectional view taken along line II' of Figure 2C is along Figure 2A A cross-sectional view taken along line II-II'.

[0008] Figure 3A is Figure 2A A top view of a MEMS microphone after the manufacturing stage. Figure 3B is along Figure 3A A cross-sectional view taken along line II' of Figure 3C is along Figure 3A A cross-sectional view taken along line II-II'.

[0009] Figure 4A is Figure 3A A top view of a MEMS microphone after the manufacturing stage. Figure 4B is along Figure 4A A cross-sectional view taken along line II' of Figure 4C is along Figure 4A A cross-sectional view taken along line II-II'.

[0010] Figure 5A is Figure 4A A top view of a MEMS microphone after the manufacturing stage. Figure 5B is along Figure 5A A cross-sectional view taken along line II' of Figure 5C is along Figure 5A A cross-sectional view taken along line II-II'.

[0011] Fig. 6A is Figure 5A A top view of a MEMS microphone after the manufacturing stage. Figure 6B is along Fig. 6A A cross-sectional view taken along line II' of Figure 6C is along Fig. 6A A cross-sectional view taken along line II-II'.

[0012] Figure 7 FIG. 4 is a schematic diagram illustrating an embodiment of an acoustic wave transducer including a piezoelectric-based MEMS microphone according to the present disclosure.

[0013] Figure 8 FIG. 4 is a schematic diagram showing an embodiment of an acoustic wave transducer including a piezoelectric MEMS microphone according to the present disclosure.

[0014] Fig. 9A is a front view of an embodiment of a capacitive MEMS microphone of the present disclosure, Fig. 9B yes Fig. 9A Rear view of a capacitive MEMS microphone.

[0015] Fig.10 is a schematic exploded view of an embodiment of a capacitive MEMS microphone of the present disclosure.

[0016] Fig.11 is a schematic exploded view of an embodiment of a capacitive MEMS microphone of the present disclosure.

[0017] Fig.12 is a schematic cross-sectional view of an embodiment of a capacitive MEMS microphone of the present disclosure.

[0018] Fig.13 is a schematic exploded view of an embodiment of a capacitive MEMS microphone of the present disclosure.

[0019] Fig.14 is a schematic cross-sectional view of an embodiment of a capacitive MEMS microphone of the present disclosure.

[0020] Fig.15 is a schematic cross-sectional view of an embodiment of a capacitive MEMS microphone of the present disclosure.

[0021] Fig.16 is a schematic cross-sectional view of an embodiment of a capacitive MEMS microphone of the present disclosure.

[0022] Fig.17 is a schematic cross-sectional view of an embodiment of a capacitive MEMS microphone of the present disclosure.

[0023] Fig.18 is a schematic cross-sectional view of an embodiment of a capacitive MEMS microphone of the present disclosure.

[0024] Fig.19A is a schematic diagram illustrating an embodiment of an acoustic wave transducer including a capacitive MEMS microphone disclosed herein, Fig.19B yes Fig.19A Top view of the acoustic wave transducer.

[0025] Fig. 20 FIG. 4 is a schematic diagram showing an embodiment of an acoustic wave transducer including a MEMS microphone according to the present disclosure.

[0026] Fig.21 FIG. 4 is a schematic diagram showing an embodiment of an acoustic wave transducer including a MEMS microphone according to the present disclosure.

[0027] Fig. 22 FIG. 4 is a schematic diagram illustrating an embodiment of the acoustic wave converter module disclosed herein.

[0028] Fig.23 is a top view of an embodiment of the acoustic wave transducer module disclosed herein. DETAILED DESCRIPTION

[0029] In the following detailed description, many specific details are set forth to provide a thorough understanding of the present disclosure. However, it should be understood by those skilled in the art that the present invention can be implemented without these specific details. In other cases, well-known methods, processes, components and circuits are not described in detail to avoid obscuring the present invention.

[0030] The present invention provides various embodiments for implementing a diaphragm that has significant performance advantages over other types of MEMS microphones used in acoustic wave transducers.

[0031] The making and use of the disclosed embodiments are discussed in detail below. However, it should be understood that the objectives provided herein provide many applicable inventive concepts that can be embodied in a variety of specific contexts. The specific embodiments discussed herein are illustrative only and are therefore not intended to limit the scope of the objectives provided.

[0032] refer to Figure 1 , Figure 1 A method 10 for forming a MEMS microphone according to aspects of the present disclosure is shown. Method 10 can be used to form different types of MEMS microphones. For example, in some embodiments, method 10 is a method for forming a piezoelectric MEMS microphone. Method 10 includes a plurality of operation steps (11, 12, 13, 14, and 15). Method 10 will be further described according to one or more embodiments. It should be noted that the operations of method 10 may be rearranged or otherwise modified within the scope of various aspects. It should also be noted that additional processes may be provided before, during, and after method 10, and some of the other processes may only be briefly described herein. Therefore, within the scope of various aspects described herein, other implementations are possible.

[0033] Figures 2A to 2C is a schematic diagram of a MEMS microphone (i.e., a piezoelectric MEMS microphone) at various stages of a method for forming a MEMS microphone according to some embodiments of the present disclosure. Figure 2A, receiving a carrier 102. In some embodiments, the carrier 102 may be glass, but the present disclosure is not limited thereto. For example, as a material for the carrier 102, quartz or plastic made of fiberglass-reinforced plastics (FRP), polyvinyl fluoride (PVF), polyester, acrylic acid, etc. may be used. The shape of the carrier 102 may be adjusted according to different product requirements. For example, but not limited thereto, the carrier 102 may have a rectangular shape, such as Figure 2A In some embodiments, the carrier 102 has a uniform thickness. In some alternative embodiments, the carrier may have a thickness gradient, which will be described in the following description.

[0034] refer to Figures 3A to 3C In step 12, a conductive material is formed on the carrier 102 and patterned to form a first conductive layer 104. In some embodiments, the first conductive layer 104 may be patterned and defined to have a sensing portion 104s and a connecting portion 104e, such as Figure 3A As shown. The sensing portion 104s is coupled to the connecting portion 104e. The shape of the sensing portion 104s can be adjusted according to different product requirements. For example, but not limited to this, the sensing portion 104s of the first conductive layer 104 can have a rectangular shape, such as Figure 3A In addition, FIG. 3A to FIG. 3C As shown, a portion of the carrier 102 is exposed through the first conductive layer 104 .

[0035] refer to FIG. 4A to FIG. 4C In step 13, a piezoelectric material is formed and patterned to form a piezoelectric layer 106 on the first conductive layer 104. The piezoelectric material may include an organic flexible material such as poly(vinylidene fluoride) (PVDF) or a copolymer, poly(vinylidene fluoride-co-trifluoroethylene, P(VDF-TrFE)) or other ferroelectric polymers, or an inorganic flexible material such as PZT, such as quartz, single crystal quartz, or any other suitable piezoelectric material, such as aluminum nitride (AlN), zinc oxide (ZnO), cadmium sulfide (CdS), lead titanate (PbTiO3), lead zirconate titanate (PZT), lithium niobate (LiNbO3), lithium tantalate (LiTaO3), potassium niobate (KNbO3), lithium tetraborate (Li2B4O7, LTB), lanthanum gallium silicate (Langasite, La3Ga5SiO 14 ), gallium arsenide (GaAs), sodium niobate (Ba2NaNb5O 15 ), bismuth germanium oxide (Bi 12 GeO 20, BGO), indium arsenide (InAs), indium antimonide (InSb), or other non-centrosymmetric materials, in substantially pure form or in combination with one or more additional materials. The thickness of the piezoelectric layer 106 is between about 2 microns and about 30 microns, but the present disclosure is not limited thereto. In some embodiments, the piezoelectric layer 106 is formed to cover a portion of the sensing portion 104s of the first conductive layer 104 and a portion of the carrier 102, such as Figure 4A and Figure 4B shown.

[0036] refer to Figures 5A to 5C In step 14, another conductive material is formed and patterned to form a second conductive layer 108 on the piezoelectric layer 106. In some embodiments, the second conductive layer 108 may be patterned and defined as having a sensing portion 108s and a connecting portion 108e, such as Figure 5A As shown. The sensing portion 108s is coupled to the connecting portion 108e. Furthermore, as Figure 5A As shown, the sensing portion 108s of the second conductive layer 108 overlaps the sensing portion 104s of the first conductive layer 104, and a portion of the carrier 102 is exposed through the first conductive layer 104. In some embodiments, the first conductive layer 104 and the second conductive layer 108 may include the same material, but the disclosure is not limited thereto. In some embodiments, the thickness of the first conductive layer 104 and the thickness of the second conductive layer 108 may be similar, but the disclosure is not limited thereto. In addition, the shape of the sensing portion 108s of the second conductive layer 108 may be similar to the shape of the sensing portion 104s of the first conductive layer 104, but the disclosure is not limited thereto.

[0037] refer to Figures 6A to 6C In step 15, a through hole 109 is formed in the carrier 102. In some embodiments, the shape of the through hole 109 may correspond to the sensing portion 104s of the first conductive layer 104 and the sensing portion 108s of the second conductive layer 108. For example, the through hole 109 may have a rectangular shape, but the present disclosure is not limited thereto. In some embodiments, as Figures 6A to 6C As shown, the width of the through hole 109 is smaller than a width of the sensing portion 104s of the first conductive layer 104 and smaller than a width of the sensing portion 108s of the second conductive layer 108. Similarly, a length of the through hole 109 is smaller than a length of the sensing portion 104s of the first conductive layer 104 and smaller than a length of the sensing portion 108s of the second conductive layer. In addition, a portion of the sensing portion 104s of the first conductive layer 104 is exposed through the through hole 109.

[0038] Thus, the piezoelectric MEMS microphone 100 is obtained. The sensing portion 104s of the first conductive layer 104, the piezoelectric layer 106, and the sensing portion 108s of the second conductive layer 108 are movable components of the piezoelectric MEMS microphone 100. The connecting portion 104e of the first conductive layer 104 and the connecting portion 108e of the second conductive layer 108 provide electrical connections with other devices, such as a signal processing unit or an application specific integrated circuit (ASIC), but the present disclosure is not limited thereto. On the other hand, each material or each layer can be formed using an operation for forming a thin film transistor (TFT) on the carrier 102. Therefore, the method 10 can be easily integrated in a TFT or semiconductor manufacturing operation. Therefore, the size of the piezoelectric MEMS microphone 100 can be reduced while improving the yield.

[0039] Please refer to Figure 7 , Figure 7 Schematic diagram of an acoustic wave transducer 200a according to some embodiments of the present disclosure. In some embodiments, the piezoelectric MEMS microphone 100 is integrated into the acoustic wave transducer 200a. The acoustic wave transducer 200a may include a substrate 202, such as a glass substrate. Alternatively, the substrate 202 may be made of quartz, plastic made of fiberglass reinforced plastic (FRP), polyvinyl fluoride (PVF), polyester, acrylic, etc. In some embodiments, the substrate 202 may be used as a carrier 102 of the piezoelectric MEMS microphone 100. In such an embodiment, Figures 6A to 6C The through hole 109 is shown Figure 7 Via 203 is shown.

[0040] The piezoelectric MEMS microphone 100 is located on a substrate 202 and is electrically connected to a chip 204 via a wire 206. In some embodiments, the chip 204 may be a signal processing unit or an ASIC, but the present disclosure is not limited thereto. In addition, the chip 204 is electrically connected to another device via a line 208 formed above the substrate 202. A cover or top cover 210 is located above the substrate 202 and is fixed to the substrate 202 by a sealant 212. The sealant 212 may be an epoxy resin. This is a preferred material that will prevent moisture and oxygen from penetrating the sealant 212 as much as possible. In addition, the thickness of the sealant 212 may define the distance between the top cover 210 and the substrate 202, but the present disclosure is not limited thereto.

[0041] In some embodiments, an anisotropic conductive film (ACF) 214 may be used to provide electrical connection between the acoustic wave transducer 200 a and another device.

[0042] Please refer to Figure 8 , Figure 8 FIG. 2 is a schematic diagram of an acoustic wave converter 200b according to some embodiments of the present disclosure. It should be understood that Figure 7 and Figure 8 The same components are denoted by the same reference numerals, and repeated details may be omitted for brevity. In some embodiments, the piezoelectric MEMS microphone 100 is integrated into the acoustic wave transducer 200b. Unlike the acoustic wave transducer 200a, the acoustic wave transducer 200b has a through hole 211 that passes through the cover or top cover 210, such as Figure 8 shown.

[0043] In some embodiments, the through hole 211 may be offset from the piezoelectric MEMS microphone 100, but the present disclosure is not limited thereto. For example, although not shown, the through hole 211 may be aligned with the piezoelectric MEMS microphone 100. The shape, position and size of the through hole 211 may be modified according to different product requirements.

[0044] In some embodiments, method 10 may be used to form a capacitive MEMS microphone 300 . FIG. 9A to FIG. 18 FIG. 4 is a schematic diagram of a capacitive MEMS microphone according to some embodiments of the present disclosure. FIG. 9A to FIG. 18 Like components are denoted by like reference numerals, and repeated details may be omitted for the sake of brevity.

[0045] Please refer to Fig. 9A and Fig. 9B , Fig. 9A and Fig. 9B 3 and 4 are front and rear views of the capacitive MEMS microphone 300a, respectively. In some embodiments, the capacitive MEMS microphone 300a includes a first plate 310, a second plate 320, and a spacer layer 330 between the first plate 310 and the second plate 320. The spacer layer 330 bonds the first plate 310 and the second plate 320 together. In some embodiments, the first plate 310 may be referred to as a bottom plate, and the second plate 320 may be referred to as a top plate. Fig. 9A In some embodiments, the top plate 320 has a plurality of openings 321. In some embodiments, the openings 321 may be arranged in an array, such as Fig. 9A It should be noted that the shape, size, quantity and arrangement of the openings 321 can be adjusted or modified according to product requirements.

[0046] refer to Fig. 9B In some embodiments, the bottom plate 310 has an opening 311. The shape, size and position of the opening 311 can be adjusted or modified according to product requirements.

[0047] Please refer to Fig.10 and Fig.11 , Fig.10 and Fig.11 300a and 300b are exploded views of capacitive MEMS microphones 300a and 300b, respectively. As described above, capacitive MEMS microphone 300a includes spacer layer 330, which may be epoxy resin. This is a preferred material that will prevent moisture and oxygen from penetrating spacer layer 330 as much as possible. In some embodiments, spacer layer 330 may have a closed support wall structure, such as Fig.10 As shown. Therefore, a closed contour is formed in the spacer layer 330. In some alternative embodiments, the spacer layer 332 of the capacitive MEMS microphone 300b may have a plurality of segmented support walls, such as Fig.11 Therefore, the open outline is defined by the spacer layer 332. In such an embodiment, the shape and size of each segmented support wall 332 can be different or similar according to different product requirements.

[0048] refer to Fig.12 In some embodiments, the base plate 310 includes a carrier 312, a substrate layer 314 and a metal layer 316. An opening 311 is formed through the carrier 312. Further, the opening 311 is formed in a central area 313 of the carrier 312. The substrate layer 314 is located above the carrier 312. Further, the substrate layer 314 covers the opening 311. Therefore, the substrate layer 314 can be exposed through the opening 311 from a rear view. In some embodiments, the carrier 312 can include glass, but the present disclosure is not limited thereto. For example, the carrier 312 can include quartz, or a plastic made of FRP, PVF, polyester, acrylic, etc. In some embodiments, the substrate layer 314 can include polyimide, but the present disclosure is not limited thereto.

[0049] Still reference Fig.12 In some embodiments, the top plate 320 includes a substrate layer 322 and a metal layer 324. The opening 321 penetrates the substrate layer 322 and the metal layer 324. The metal layer 324 is located on the surface of the substrate layer 322 facing the bottom plate 310. Therefore, the metal layer 316 of the bottom plate 310 and the metal layer 324 of the top plate 320 serve as two electrodes of the capacitor. In some embodiments, the substrate layer 322 may include polyimide, but the present disclosure is not limited thereto.

[0050] In some embodiments, the spacer layer 330 or 332 is located on the bottom plate 310. The spacer layer 330 or 332 is located between the metal layer 316 of the bottom plate 310 and the metal layer 324 of the top plate 320. Therefore, it can be said that the metal layer 324 is located on the spacer layer 330 or 332. In addition, the top surface of the spacer layer 330 or 332 is in contact with the metal layer 324 of the top plate 320, and the bottom surface of the spacer layer 330 or 332 is in contact with the metal layer 316 of the bottom plate 310. The thickness of the spacer layer 330 or 332 can define the distance S between the top plate 320 and the bottom plate 310, but the present disclosure is not limited thereto. In some embodiments, when the spacer layer 330 has a closed support wall structure, the spacer layer 330 surrounds the central area 313 of the bottom plate 310. In other embodiments, when the spacer layer 332 has a segmented support wall structure, the segmented support walls are arranged to surround the central area 313 of the bottom plate 310.

[0051] In some embodiments, the spacer layer 330 includes a conductive material, such as an anisotropic conductive film (ACF), but the disclosure is not limited thereto. In such embodiments, the metal layer 324 is electrically connected to a voltage source via the spacer layer 330 .

[0052] Please refer to Fig.13 , Fig.13 3 is a schematic exploded view of a capacitive MEMS microphone 300c according to some embodiments of the present disclosure. As described above, the spacer layer may have a segmented support wall structure. That is, the spacer layer may include a plurality of segmented support walls 334 and 336, and the segmented support walls 334 and 336 are arranged to surround the central area 313 of the carrier 312. The segmented support walls 334 and 336 may include different materials. For example, some of the segmented support walls 336 may include insulating materials, and at least one of the segmented support walls 334 may include conductive materials. Fig.13 As shown, the metal layer 324 of the top plate 320 can electrically connect the conductive segmented support wall 334 and a first connection line 316a. Therefore, an electrical connection is formed between the metal layer 324 and the voltage source.

[0053] In such an embodiment, the patterned metal layer 316 has a first connection line 316a and a second connection line 316b. The first connection line 316a is physically separated and electrically separated from the second connection line 316b. In such an embodiment, the second connection line 316b also includes a sensing portion covering the central area 313 and serving as an electrode of a capacitor, and a connecting portion providing an electrical connection between the sensing portion and a voltage source. The first connection line 316a serves as a line for electrically connecting the metal layer 324 of the top plate 320 via the conductive segmented support wall 334. Therefore, the metal layer 324 of the top plate 320 is electrically connected to the voltage source through the conductive segmented support wall 334. Therefore, the metal layer 324 of the top plate 320 and the metal layer 316 of the bottom plate 310 (i.e., the sensing portion of the second connection line 316b) serve as two electrodes of the capacitor.

[0054] refer to Fig.14 In some embodiments, the spacer layer 330 or 332 of the capacitive MEMS microphone 300d may include an insulating material. A conductive adhesive layer 336 is provided to provide adhesion and electrical connection between the spacer layer 330 or 332 and the metal layer 324 of the top plate 320. In such an embodiment, a top surface and side walls of the spacer layer 330 or 332 are made relatively flat so that the conductive adhesive layer 336 can be smoothly placed along the spacer layer 330 or 332. Therefore, the metal layer 324 is electrically connected to the voltage source through the conductive adhesive layer 336 and the first connection line 316a of the metal layer 316, so that the metal layer 324 serves as an electrode of the capacitor.

[0055] refer to Fig.15 In some embodiments, the capacitive MEMS microphone 300e further includes a buffer layer 340 located on the metal layer 316. In other words, the buffer layer 340 is located between the metal layer 316 and the spacer layer 330 or 332. The buffer layer 340 may include a semiconductor material, such as silicon, amorphous silicon, etc. In such an embodiment, the buffer layer 340 allows the metal layer 316 of the bottom plate 310 to have a more flexible pattern. In addition, the thickness of the buffer layer 340 helps to adjust the distance S between the two electrodes (i.e., the metal layer 324 and the metal layer 316), and the material used to form the buffer layer 340 can provide different dielectric constants. Therefore, the characteristics of the capacitor can be changed by the thickness and material of the buffer layer 340. The buffer layer 340 also helps to change the damping characteristics of the metal layer 316 of the bottom plate 310. Therefore, the frequency response of the capacitive MEMS microphone 300e can be changed.

[0056] refer to Fig.16In some embodiments, the capacitive MEMS microphone 300f further includes another buffer layer 342 located on the metal layer 324. In other words, the metal layer 324 is located between the buffer layer 342 and the substrate layer 322. In addition, the spacer layer 330 is located between the buffer layer 340 and the buffer layer 342. The buffer layer 342 may include a semiconductor material, such as silicon, amorphous silicon, etc. In addition, the buffer layers 340 and 342 may include the same material. In some alternative embodiments, the buffer layers 340 and 342 may include different materials. In such an embodiment, the thickness of the buffer layer 342 helps to adjust the distance between the two electrodes (i.e., the metal layer 324 and the metal layer 316), and the material used to form the buffer layer 342 may provide different dielectric constants. Therefore, the characteristics of the capacitor can be changed by the thickness and material of the buffer layer 342. As described above, the buffer layer 342 further helps to change the damping characteristics of the metal layer 324 of the top plate 320. Therefore, the frequency response of the capacitive MEMS microphone 300f can be changed.

[0057] refer to Fig.17 In some embodiments, the carrier plate 312 of the bottom plate 310 may have a gradient thickness. In such an embodiment, the top plate 320 and the bottom plate 310 are parallel to each other. Therefore, due to the gradient thickness of the carrier plate 312 of the bottom plate 310, the capacitive MEMS microphone 300g may have an inclined sound receiving surface. In such an embodiment, a directional microphone is provided. The directional capacitive MEMS microphone 300g has a higher sensitivity to sound waves from a specific direction and a lower sensitivity to sound waves from other directions.

[0058] refer to Fig.18 In some embodiments, the spacer layer 330 may have a non-uniform thickness. Therefore, the top plate 320 is not parallel to the bottom plate 310. Therefore, the spacing between the metal layer 324 and the metal layer 316 is not uniform. Fig.18 As shown, multiple spacing distances S1, S2, Sn are obtained. In such an embodiment, the capacitive MEMS microphone 300h may have an inclined sound receiving surface due to the inconsistent thickness of the spacing layer 330, thereby providing a directional microphone. As described above, the directional capacitive MEMS microphone 300h has a higher sensitivity to sound waves from a specific direction and a lower sensitivity to sound waves from other directions.

[0059] According to the capacitive MEMS microphones 300a to 300h, as the sound waves move or vibrate the metal layer 316 of the bottom plate 310 above the opening 311, the spacing distance S (and S1 and S2 to Sn) changes. When the spacing S changes, the capacitance of the capacitor changes, thereby generating a signal. Due to the different configurations of the spacing layers 330 and 332 (such as Fig. 9Aand 9B 12) and various material selections for the spacer layers 334 and 336 (eg Fig.13 and 14 ), it is easy to establish different electrical connections between metal layers 316 and 324. By adding buffer layers 340 and 342 (as shown in FIG. Fig.15 and 16 ), the characteristics of the capacitor can be easily modified. By using a carrier 312 with a gradient thickness (such as Fig.17 ) or using a spacer layer 330 of different thickness (such as Fig.18 In addition, the capacitive MEMS microphones 300a to 300h can be integrated with each other according to product requirements to improve the flexibility of product design.

[0060] Please refer to Fig.19A and 19B to 21, Fig.19A and 19B 21 are schematic diagrams of acoustic wave converters 400a to 400c according to some embodiments of the present disclosure. It should be understood that, Fig.19A and FIG. 19B to FIG. 21 Like components are denoted by like reference numerals, and repeated details may be omitted for the sake of brevity.

[0061] In some embodiments, the capacitive MEMS microphone 300 (ie, the capacitive MEMS microphones 300a to 300h) may be integrated into the acoustic wave transducer 400a. Fig.19A As shown, the carrier 312 of the base plate 310 of the capacitive MEMS microphone 300 is used as the substrate 402 of the acoustic wave transducer 400 a .

[0062] The capacitive MEMS microphone 300 is electrically connected to a chip 404 via a first connection line 316a of the metal layer 316 of the bottom plate 310, but the disclosure is not limited thereto. In some embodiments, the chip 404 may be a signal processing unit or an ASIC, but the disclosure is not limited thereto. The ASIC 404 may be used to process the voltage signal generated from the MEMS microphone 300 to perform filtering operations and amplification operations. Therefore, the voltage signal obtained from the MEMS microphone 300 may be determined.

[0063] A cover or top cover 406 is located above the substrate 402 and is fixed to the substrate 402 by a sealant 408. In some embodiments, the sealant 408 can be located on the substrate layer 314 of the bottom plate 310, such as Fig.19AAs shown, but the present disclosure is not limited to this. In other embodiments, although not shown, the encapsulant 408 can be located on the metal layer 316 of the base plate 310. In some embodiments, the encapsulant 408 can be an epoxy resin. In some alternative embodiments, the encapsulant 408 can include a conductive material. This is a preferred material that will prevent moisture and oxygen from penetrating the encapsulant 408 as much as possible. In addition, the thickness of the encapsulant 408 can define the distance between the top cover 406 and the carrier 312, but the present disclosure is not limited to this. In some embodiments, the ASIC 404 and portions of the capacitive MEMS microphone 300 (i.e., the metal layer 316, the spacer layer 330 / 332, and the top plate 320) are located within the area defined by the encapsulant 408, such as Fig.19A and 19B In other words, the encapsulant 408 surrounds the metal layer 316 of the bottom plate 310 , the spacer layer 330 or 332 , the top plate 320 , and the ASIC 404 .

[0064] Still reference Fig.19A In some embodiments, when the sealant 408 includes a conductive material, the sealant 408 provides protection from external interference. In such an embodiment, the conductive sealant 408 can be grounded, but the present disclosure is not limited thereto.

[0065] refer to Fig. 20 In some embodiments, the acoustic wave converter 400b may include a conductive layer 410 located on an outer surface 403 of the substrate 402, and a conductive layer 412 located on an outer surface 407 of the top cover 406. The conductive layers 410 and 412 provide protection from external interference. In such an embodiment, the conductive sealant 408 and the conductive layers 410 and 412 may be grounded, but the present disclosure is not limited thereto.

[0066] refer to Fig.21 In some embodiments, the acoustic wave transducer 400c may have the capacitive MEMS microphone 300 located in an area surrounded by the encapsulant 408, while the ASIC 404 is located outside the area. In other words, the encapsulant 408 surrounds the spacer layer 330 or 332 and the top plate 320. In such an embodiment, the ASIC 404 and the MEMS microphone 300 may be electrically connected via the metal layer 316 of the bottom plate 310. In other embodiments, the electrical connection between the MEMS microphone 300 and the ASIC 404 may be provided by the ACF, but the present disclosure is not limited thereto.

[0067] refer to Fig. 22In some embodiments, the acoustic wave transducers 400a, 400b, and / or 400c may be integrated to form an acoustic wave transducer module 500a. It should be noted that, according to different product requirements, each of the acoustic wave transducers 400a, 400b, and 400c may include at least a MEMS microphone 300 (i.e., capacitive MEMS microphones 300a to 300h) or a MEMS microphone 100 (i.e., piezoelectric MEMS microphones 100a to 100d, although not shown).

[0068] For example, the acoustic wave transducer module 500a includes two vertically stacked and integrated acoustic wave transducers 400a-1 and 400a-2. In some embodiments, the carrier 312 of the bottom plate 310 of the lower acoustic wave transducer 400a-1 can be used as the bottom substrate 502 of the acoustic wave transducer module 500a, and the carrier 312 of the bottom plate 310 of the upper acoustic wave transducer 400a-2 can be used as the top substrate 504 of the acoustic wave transducer module 500a. In addition, the two acoustic wave transducers 400a-1 and 400a-2 can share a top cover, which is used as an intermediate spacer 506 between the two MEMS microphones 300. That is, the two acoustic wave transducers 400a-1 and 400a-2 are integrated in a face-to-face manner. In such an embodiment, the opening 311 of the lower acoustic wave transducer 400a-1 and the opening 311 of the upper acoustic wave transducer 400a-2 face opposite directions. Therefore, the MEMS microphones 300 of the two acoustic wave transducers 400a-1 and 400a-2 can be used to detect acoustic waves from opposite directions. Therefore, the practicality of the acoustic wave transducer module 500a is further improved.

[0069] Furthermore, while in some embodiments, each of the two MEMS microphones 300 is independently operated by a respective ASIC 404 , in other embodiments, the two MEMS microphones 300 share one ASIC 404 and are both operated by the same ASIC 404 .

[0070] Still reference Fig. 22 In some embodiments, conductive layers 510 and 512 are formed on the outer surface of the acoustic wave converter module 500a. For example, the conductive layer 510 may be located on an outer surface 503 of the bottom substrate 502 (i.e., the carrier 312 of the bottom plate 310 of the lower acoustic wave converter 400a-1), and the conductive layer 512 may be located on an outer surface 505 of the top substrate 504 (i.e., the carrier 312 of the bottom plate 310 of the upper acoustic wave converter 400a-2). As described above, the conductive layers 510 and 512 may provide protection from external interference.

[0071] Furthermore, in some embodiments, the sealant 408 of the lower acoustic wave transducer 400a-1 and the upper acoustic wave transducer 400a-2 may include a conductive material. Therefore, the conductive sealant 408 also provides protection from external interference.

[0072] refer to Fig.23 , the acoustic wave converter module 500b includes more than two acoustic wave converters integrated together. In some embodiments, the acoustic wave converter module 500b may include a laterally integrated acoustic wave converter 400a, but the present disclosure is not limited thereto. For example, the acoustic wave converter module 500b may include a plurality of laterally integrated acoustic wave converters 400b-1, 400b-2, and 400b-3, such as Fig.23 shown.

[0073] In such an embodiment, all of the acoustic wave transducers 400b-1 to 400b-3 may share the same carrier of the base plate, which serves as the bottom substrate 502 of the acoustic wave transducer module 500b. Fig.23 Although not shown, all of the acoustic wave transducers 400 b - 1 to 400 b - 3 may share the same top cover. However, each of the MEMS microphones 300 (i.e., the capacitive MEMS microphones 300 a to 300 h ) or the MEMS microphones 100 (i.e., the piezoelectric MEMS microphones 100 a to 100 d , although not shown) is separated from each other by the sealing glue 408 .

[0074] In such an embodiment, the MEMS microphone 300 or 100 may share the same ASIC 404. That is, the MEMS microphone 300 or 100 is electrically connected to the same ASIC 404 via the first connection line 316a of the metal layer 316. However, in other embodiments, an ACF may be used to provide an electrical connection between the ASIC 404 and the MEMS microphone 300 or 100. In such an embodiment, only one ASIC 404 is used to process the voltage signal generated from the MEMS microphone 300 to perform the filtering operation and the amplification operation. Therefore, the voltage signal obtained from the MEMS microphone 300 can be determined.

[0075] Additionally, while in some embodiments the MEMS microphones 300 share one ASIC 404 and are operated by the same ASIC 404 , in other embodiments each MEMS microphone 300 may be independently operated by a respective ASIC.

[0076] The acoustic wave converter module 500b can have MEMS microphones 300 or 100 of various sizes to provide a desired frequency response. In other words, the acoustic wave converter module 500b can be used to detect acoustic waves of various frequencies. Therefore, the practicality of the acoustic wave converter module 500b is further improved.

[0077] As described above, a conductive layer may be formed on the outer surface of the top and bottom substrates of the acoustic wave transducer module 500b to provide protection from external interference. The sealant 408 may contain a conductive material, and the conductive sealant 408 may also be used to protect from external interference.

[0078] According to the present disclosure, various piezoelectric MEMS microphones and various capacitive MEMS microphones are provided. The piezoelectric MEMS microphone and the capacitive MEMS microphone can be manufactured by TFT manufacturing operations. Therefore, the size of the piezoelectric MEMS microphone and the capacitive MEMS microphone can be reduced to less than about 50 mm. In some embodiments, the size of the piezoelectric MEMS microphone and the capacitive MEMS microphone can be reduced to between about 20 microns and about 50 mm, but the present disclosure is not limited thereto. In addition, various MEMS microphones can be integrated with ASICs to form an acoustic wave converter, and the acoustic wave converter can be integrated into a converter module. By selecting various MEMS microphones and various acoustic wave converters, various converter modules can be provided for different product requirements. Therefore, the practicality and design flexibility of the acoustic wave converter are improved.

[0079] The features of several embodiments have been summarized above so that those skilled in the art can better understand the aspects of the present disclosure. Those skilled in the art will appreciate that they can easily use the present disclosure as a basis for designing or modifying other processes and structures to implement the same purposes and / or achieve the same advantages of the embodiments introduced herein. Those skilled in the art will also appreciate that such equivalent constructions should not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and modifications to the present disclosure without departing from the spirit and scope of the present disclosure.

[0080] Explanation of symbols

[0081] 10: Methods

[0082] 11: Steps

[0083] 12: Steps

[0084] 13: Steps

[0085] 14: Steps

[0086] 15: Steps

[0087] 100: Piezoelectric MEMS microphone

[0088] 102: Carrier board

[0089] 104: First conductive layer

[0090] 104e: Connection part

[0091] 104s: Sensing part

[0092] 106: Piezoelectric layer

[0093] 108: Second conductive layer

[0094] 108e: Connection part

[0095] 108s: Sensing part

[0096] 109: Through hole

[0097] 200: Sound wave converter

[0098] 200a-200b: Acoustic Transducer

[0099] 202: Substrate

[0100] 203: Through hole

[0101] 204: Chip

[0102] 206: Wiring

[0103] 208: Line

[0104] 210: Cover / top cover

[0105] 211: Through hole

[0106] 212: Sealing

[0107] 214: Anisotropic Conductive Film (ACF)

[0108] 300: Capacitive MEMS microphone

[0109] 300a-300h: Capacitive MEMS microphone

[0110] 310: First plate / bottom plate

[0111] 311: Opening

[0112] 312: Carrier board

[0113] 313: Central Area

[0114] 314: substrate layer

[0115] 316: Metal layer

[0116] 316a: First Connection

[0117] 316b: Second connection

[0118] 320: Second board / top board

[0119] 321: Opening

[0120] 322: substrate layer

[0121] 324: Metal layer

[0122] 330: Spacer layer

[0123] 332: Spacer / Support Wall

[0124] 334: Spacer / Support Wall

[0125] 336: Spacer layer / support wall / conductive adhesive layer

[0126] 340: Buffer layer

[0127] 342: Buffer layer

[0128] 400a-400c: Acoustic Wave Transducer

[0129] 400a-1: Lower acoustic converter

[0130] 400a-2: Upper Sonic Transducer

[0131] 400b-1: Acoustic Transducer

[0132] 400b-2: Acoustic Transducer

[0133] 400b-3: Acoustic Transducer

[0134] 402: Substrate

[0135] 403: External surface

[0136] 404: Chip / ASIC

[0137] 406: Cover / top cover

[0138] 407: External surface

[0139] 408: Sealing

[0140] 410: Conductive layer

[0141] 412: Conductive layer

[0142] 500a: Acoustic Transducer Module

[0143] 500b: Sound wave converter module

[0144] 502: Bottom substrate

[0145] 503: External surface

[0146] 504: Top substrate

[0147] 505: Outer surface

[0148] 506: Spacer

[0149] 510: Conductive layer

[0150] 512: Conductive layer

[0151] I-I': Section line

[0152] II-II': Section line

[0153] III-III': Section line

[0154] S: spacing distance

[0155] S1-Sn: Separation distance

Claims

1. An acoustic wave converter, comprising: The first board contains: a carrier having a first opening formed in a central region of the carrier; A first substrate layer is located on the carrier and above the first opening; and A first metal layer located on the first substrate layer, wherein the first metal layer includes a first connection line and a second connection line, and the second connection line is separated from the first connection line and covers the central area; a spacer layer located on the first plate and surrounding the central area, wherein the spacer layer comprises at least one supporting wall, the supporting wall being in contact with the first connecting line; and A second plate, which is above the first plate and the spacer layer, and comprises: a second substrate layer; A second metal layer located on the spacer layer; and A plurality of second openings penetrate the second substrate layer and the second metal layer. 2 . The acoustic wave transducer according to claim 1 , wherein the spacer layer comprises a plurality of support walls surrounding the central region.

3. The acoustic wave converter according to claim 1, further comprising a conductive adhesive layer located on the top and sidewalls of the spacer layer and electrically connected to the second metal layer. The acoustic wave transducer according to claim 1 , wherein the carrier has a thickness gradient.

5. An acoustic wave converter module, comprising: The first sound wave converter, comprising: The first base plate comprises: a first glass layer having a first opening formed in a central region of the first glass layer; a first substrate layer located on the first glass layer and above the first opening; and A first metal layer located on the first substrate layer, wherein the first metal layer includes a first connection line and a second connection line, and the second connection line is separated from the first connection line and covers the central area; a first spacer layer located on the first bottom plate and surrounding the central area of ​​the first glass layer, wherein the first spacer layer comprises at least one supporting wall, and the supporting wall is in contact with the first connecting line; and A first top plate having a plurality of second openings and comprising: a second substrate layer; and a second metal layer, which is located on the first spacer layer; a first sealing wall, which is located on the first bottom plate of the first sound wave converter; A top cover, which is located on the first sealing wall; and The first signal processing circuit is coupled to the first metal layer and the second metal layer.

6. The acoustic wave transducer module of claim 5, wherein the top cover comprises: second glass layer; and A first conductive layer is located on the second glass layer.

7. The acoustic wave converter module according to claim 5, further comprising a second acoustic wave converter, wherein the second acoustic wave converter comprises: A second base plate, comprising a third glass layer having a third opening, a third substrate layer located on the second glass layer, and a third metal layer located on the third substrate layer; A second spacer layer, which is located on the second bottom plate; and The second top plate has a plurality of fourth openings and includes a fourth substrate layer and a fourth metal layer located on the second spacer layer. 8 . The sound wave converter module according to claim 7 , further comprising a second sealing wall located between the top cover of the first sound wave converter and the first bottom plate and surrounding the second sound wave converter. 9 . The sound wave converter module according to claim 7 , further comprising a second sealing wall located on the first bottom plate of the first sound wave converter and surrounding the second sound wave converter.

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