MEMS microphone

Abstract

A MEMS microphone, comprising: a substrate having a back cavity; a back plate spaced apart from the substrate; a diaphragm disposed on the substrate and located between the substrate and the back plate, wherein the diaphragm comprises a main body portion, an edge portion, isolation islands and beam structures, the main body portion being spaced apart from the substrate and the back plate, the edge portion being fixedly connected to the substrate, a plurality of the isolation islands being provided and being spaced apart from the main body portion, a gap being formed between each of the isolation islands and the main body portion, a plurality of the beam structures being provided and being arranged at intervals around the main body portion, one beam structure being provided between any two adjacent isolation islands, and the beam structure being configured to connect the main body portion and the edge portion; and a connector configured to connect each of the isolation islands to at least one of the substrate and the back plate. In the present invention, the isolation islands are fixedly connected to the back plate or the substrate, so that the degree of freedom in designing the isolation islands can be optimized, and the robustness of the diaphragm can also be improved.

Description

MEMS microphone

[0001] This application incorporates by reference in its entirety the U.S. Patent Application No. US 18 / 748,093, filed on June 20, 2024, entitled “MEMS microphone”, which is incorporated by reference in its entirety. TECHNICAL FIELD

[0002] Embodiments of the present application relate to the field of microphone technology, in particular to a MEMS microphone. BACKGROUND

[0003] One of the most widely used and high performance microphones is a Micro-Electro-Mechanical-System Microphone (MEMS microphone), which is also called a silicon-based microphone or a silicon microphone because it is made of silicon-based semiconductor materials. The packaging volume of the MEMS microphone is smaller than that of a traditional electret microphone, and the MEMS microphone is increasingly widely used. TECHNICAL PROBLEM

[0004] In the prior art, a silicon microphone generally etches a plurality of connecting beams spaced apart from each other at the edge of a diaphragm along the circumference of the diaphragm. The connecting beams are composed of a plurality of fins that isolate the connecting beams from the rest of the diaphragm. The center part of the diaphragm is connected to the substrate by fixing the connecting beams to the substrate. Although this design method can reduce the rigidity of the diaphragm, the fins isolating the connecting beams can be warped due to stress gradients and / or static friction against the substrate or the fixed backplate structure because the diaphragm is made of flexible material.

[0005] Therefore, it is necessary to provide a new MEMS microphone to solve the above technical problems. TECHNICAL SOLUTION

[0006] Embodiments of the present application provide a MEMS microphone, comprising: a substrate having a back cavity; a backplate spaced apart from the substrate; a diaphragm disposed on the substrate and located between the substrate and the backplate; the diaphragm comprises a main body part, an edge part, an isolation island and a beam structure, the main body part is spaced apart from the substrate and the backplate, the edge part is fixedly connected to the substrate, the isolation island is a plurality of and is spaced apart from the main body part, a gap is formed between each of the isolation islands and the main body part; the beam structure is a plurality of and is spaced apart around the main body part, there is the beam structure between any two adjacent isolation islands, the beam structure is used for connecting the main body part and the edge part; a connecting piece configured to connect each of the isolation islands to at least one of the substrate and the backplate. ADVANTAGEOUS EFFECTS

[0007] The beneficial effects of the present application are: a MEMS microphone is provided, the isolation island is fixedly connected with at least one of the back plate and the substrate through the connecting piece, so that the isolation island can be fixed, and the isolation island is prevented from being warped due to stress gradient and / or static friction force on the substrate or fixed back plate structure. On the one hand, due to the fixed position of the isolation island, the size design of the isolation island is less limited, and the freedom of optimizing the design of the isolation island is improved; on the other hand, due to the fixed position of the isolation island, when the diaphragm moves upward under high pressure, the isolation island structure will provide a certain degree of ventilation, and the robustness of the diaphragm is improved. BRIEF DESCRIPTION OF DRAWINGS

[0008] One or more embodiments are illustrated by way of example in the figures that form a part of this patent document, these illustrative examples do not limit the embodiments and elements having the same reference numerals in different figures indicate like elements unless otherwise indicated, the figures in the drawings are not to scale.

[0009] Fig. 1 is a structural diagram of a MEMS microphone according to an embodiment of the present application;

[0010] Fig. 2 is a structural diagram of a diaphragm and a substrate of the MEMS microphone according to the embodiment of the present application;

[0011] Fig. 3 is a sectional view of the MEMS microphone according to the embodiment of the present application at an isolation island;

[0012] Fig. 4 is a structural diagram of the MEMS microphone in Fig. 1;

[0013] Fig. 5 is a bottom view of the MEMS microphone in Fig. 1 at the isolation island and the connecting piece;

[0014] Fig. 6 is a structural diagram of a MEMS microphone according to an embodiment of the present application;

[0015] Fig. 7 is a top view of the MEMS microphone according to the embodiment of the present application at the isolation island and the connecting piece;

[0016] Fig. 8 is a structural diagram of a MEMS microphone according to an embodiment of the present application. Embodiments of the present application

[0017] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the embodiments of the present application will be described in detail below with reference to the drawings. However, those skilled in the art can understand that in the embodiments of the present application, many technical details are proposed in order to make the readers better understand the present application. However, the technical solutions claimed by the present application can be realized even without these technical details and various changes and modifications based on the following embodiments.

[0018] The embodiment of the present application aims to provide a MEMS microphone capable of avoiding warping of the isolation island.

[0019] The embodiment of the present application provides a MEMS microphone, the isolation island is fixedly connected with at least one of the back plate and the substrate through the connecting piece, so that the isolation island can be fixed, and warping of the isolation island due to stress gradient and / or static friction force on the substrate or fixed back plate structure is prevented. On the one hand, since the position of the isolation island is fixed, the size design of the isolation island is less limited, and the freedom of optimization of the isolation island design is improved; on the other hand, since the position of the isolation island is fixed, when the diaphragm moves upward under high pressure, the isolation island structure will provide a certain amount of ventilation, and the robustness of the diaphragm is improved.

[0020] Embodiment one

[0021] Please refer to FIG. 1 and FIG. 2, the embodiment one of the present application provides a MEMS microphone 10, which comprises a substrate 5 with a back cavity 51, a back plate 1 arranged in a spaced manner with the substrate 5, and a diaphragm 2 arranged between the substrate 5 and the back plate 1 and provided on the substrate 5. Specifically, the diaphragm 2 comprises a main body part 21 arranged in a spaced manner with the substrate 5 and the back plate 1, an edge part 22 fixedly connected to the substrate 5 through a fixing part 6, a plurality of isolation islands 23 arranged in a spaced manner with the main body part 21, and a plurality of beam structures 25. The main body part 21 and each of the plurality of isolation islands form a gap 24 therebetween, and the plurality of beam structures 25 are arranged in a spaced manner around the main body part 21, and any two adjacent isolation islands 23 have the beam structure 25 therebetween. One end of the beam structure 25 is connected to the edge part 22, and the other end is connected to the main body part 21. In addition, the MEMS microphone 10 further comprises a connecting piece 3 configured to fixedly connect each of the isolation islands 23 with the substrate 5.

[0022] Specifically, the gap 24 is an annular gap arranged around the isolation island 23. Therefore, the isolation island 23 is arranged in a spaced manner with the main body part 21 and the beam structure 25. In addition, the isolation island 23 and the main body part 21 are located on the same plane. It should be noted that the beam structure 25 is located between two adjacent gaps 24.

[0023] Please refer to FIG. 1 and FIG. 2, the isolation island 23 is a rounded rectangular shape, and correspondingly, the gap 24 is a rounded rectangular shape in a ring shape. In other embodiments, the isolation island 23 can also be circular or polygonal, and can be designed according to actual needs, which is not limited here.

[0024] The MEMS microphone 10 provided by the embodiment one of the present application is characterized in that each of the isolation islands 23 is fixedly connected to the substrate 5 through the connecting piece 3, so that the isolation island 23 can be fixed and prevented from being warped due to stress gradient and / or static friction force on the substrate 5 or the fixed backplate structure. On the one hand, since the position of the isolation island 23 is fixed, the size of the isolation island 23 is less limited, so that the freedom of the design of the isolation island 23 is optimized. On the other hand, since the position of the isolation island 23 is fixed, when the diaphragm 2 moves upward under high pressure, the structure of the isolation island 23 will provide a certain amount of ventilation, improving the robustness of the diaphragm 2.

[0025] Please refer to FIG. 3, the connecting piece 3 includes an anchor 33, and the anchor 33 is fixedly connected between the substrate 5 and each of the isolation islands 23, so as to realize the fixed connection between the corresponding isolation island 23 and the substrate 5 through the connecting piece 3. Please refer to FIG. 4, the anchor 33 is a circularly rounded rectangle in cross section perpendicular to the vibration direction of the diaphragm 2. In other embodiments, the cross section of the anchor 33 can also be a circular ring or a variable ring, which can be designed according to actual needs, and is not limited here.

[0026] Please refer to FIG. 3 and FIG. 4, the anchor 33 is filled with an oxide isolation layer 34. In other embodiments, the anchor 33 is filled with other materials, and the specific material type can be selected according to actual needs, and is not limited here.

[0027] In other embodiments, the connecting piece 3 can only include an oxide isolation layer, which is fixedly connected between the substrate 5 and the corresponding isolation island 23, so as to fixedly connect the substrate 5 and the corresponding isolation island 23.

[0028] Please refer to FIG. 3 and FIG. 4, along the vibration direction of the diaphragm 2, the orthographic projection of the corresponding isolation island 23 on the substrate 5 covers the orthographic projection of the connecting piece 3 on the substrate 5, so that the connecting piece 3 is only connected with the diaphragm 2 and the corresponding isolation island 23, avoiding interference between the connecting piece 3 and other positions (such as the vibration part or the beam structure 25) of the diaphragm 2.

[0029] In the embodiment, each of the isolation islands 23 is fixedly connected to the base 5 by the connecting piece 3, so that the isolation island 23 is fixed to prevent the isolation island 23 from being warped due to stress gradient and / or static friction force on the base 5 or fixed back plate structure. On the one hand, due to the fixed position of the isolation island 23, the size of the isolation island 23 is less limited, and the freedom of the design of the isolation island 23 is optimized. On the other hand, due to the fixed position of the isolation island 23, when the diaphragm 2 moves upward under high pressure, the isolation island 23 will provide a certain amount of ventilation, improving the robustness of the diaphragm 2.

[0030] Embodiment two

[0031] Please refer to FIG. 5 and FIG. 6, the difference between the second embodiment of the present application and the first embodiment is that the connecting piece 3 is configured to fixedly connect each of the isolation islands 23 and the back plate 1 to fix the isolation island 23.

[0032] Please refer to FIG. 5, the connecting piece 3 includes a first connecting part 31 and a second connecting part 32 fixedly connected to the first connecting part 31, the first connecting part 31 is fixedly connected to the back plate 1, and the second connecting part 32 is fixedly connected to a corresponding one of the isolation islands 23 to fixedly connect the connecting piece 3 between the back plate 1 and the corresponding isolation island 23.

[0033] Please refer to FIG. 5, in the direction perpendicular to the vibration direction of the diaphragm 2, the cross-sectional area of the first connecting part 31 is greater than the cross-sectional area of the second connecting part 32, forming the connecting piece 3. As shown in FIG. 6, the cross section of the first connecting part 31 and the cross section of the second connecting part 32 are both circular. In other embodiments of the present application, the cross section of the first connecting part 31 and the cross section of the second connecting part 32 can also be rectangular, trapezoidal or other shapes, and the cross-sectional area of the first connecting part 31 can also be smaller than the cross-sectional area of the second connecting part 32, which can be designed according to actual needs, and is not limited here.

[0034] Please refer to FIG. 5, along the vibration direction of the diaphragm 2, an air gap 4 is formed between each of the isolation islands 23 and the back plate 1. The position where the first connecting part 31 and the second connecting part 32 are fixedly connected forms a connecting surface 35.

[0035] Along the vibration direction of the diaphragm 2, the air gap 4 includes a first gap 41 and a second gap 42. The first gap 41 is formed between the surface of the back plate 1 facing the plurality of isolation islands 23 and the connecting surface 35, and the second gap 42 is formed between the surface of the isolation island 23 facing the back plate 1 and the connecting surface 35.

[0036] Referring to Fig. 5, along the vibration direction of the diaphragm 2, the orthographic projection of each isolation island 23 on the back plate 1 covers the orthographic projection of the connecting piece 3 on the back plate 1, so that the connecting piece 3 is connected only with the corresponding isolation island 23 on the diaphragm 2, avoiding interference with other positions of the diaphragm 2, such as the vibration part or beam structure 25.

[0037] Referring to Figs. 5 and 6, along the vibration direction of the diaphragm 2, the orthographic projection of the connecting piece 3 on the corresponding isolation island 23 is located at the center of the isolation island 23, so as to connect the back plate 1 from the center position of the isolation island 23.

[0038] The connecting piece 3 is integrally formed with the back plate 1. The connecting piece 3 can be formed on the corresponding isolation island 23 by deposition. At this time, the connecting piece 3 and the back plate 1 can be made of the same material, the connecting piece 3 is first deposited on the isolation island 23, and then the back plate 1 is continuously deposited above the connecting piece 3, so that the connecting piece 3 is integrally formed with the back plate 1.

[0039] In the embodiment, each isolation island 23 is fixedly connected with the back plate 1 through the connecting piece 3, so that the isolation island 23 can be fixed to prevent the isolation island 23 from being warped due to stress gradient and / or static friction force on the substrate 5 or fixed back plate structure. On the one hand, since the position of the isolation island 23 is fixed, the size design of the isolation island 23 is less limited, optimizing the design freedom of the isolation island 23. On the other hand, since the position of the isolation island 23 is fixed, when the diaphragm 2 moves upward under high pressure, the isolation island 23 structure will provide a certain degree of ventilation, improving the robustness of the diaphragm 2.

[0040] Embodiment three

[0041] Referring to Fig. 8, the difference between the third embodiment of the present application and the above two embodiments is that the isolation island 23 is fixedly connected with the back plate 1 and the substrate 5 through the connecting piece 3, thereby further improving the firmness of the isolation island 23 and reducing the span of the back plate 1, thereby increasing the stiffness of the back plate 1 while maintaining the span of the diaphragm 2 and maintaining the low stiffness of the diaphragm 2.

[0042] It should be further noted that those skilled in the art can understand that, in the embodiments of the present application, many technical details are proposed in order to enable the reader to better understand the present application. However, the technical solutions claimed by the present application can be realized even without these technical details and various changes and modifications based on the above embodiments. The division of the above embodiments is for the convenience of description, and should not constitute any limitation on the specific implementation mode of the present application. The embodiments can be combined and referenced with each other without contradiction.

Claims

1. A MEMS microphone, comprising: The base has a dorsal cavity; Back plate, spaced apart from the base; A diaphragm is disposed on the substrate and located between the substrate and the back plate. The diaphragm includes a main body, an edge portion, isolation islands, and beam structures. The main body is spaced apart from the substrate and the back plate. The edge portion is fixedly connected to the substrate. There are multiple isolation islands spaced apart from the main body, and each isolation island forms a gap with the main body. There are multiple beam structures spaced around the main body, and a beam structure is provided between any two adjacent isolation islands. The beam structure is used to connect the main body and the edge portion. The connector is configured to connect each of the isolation islands to at least one of the substrate and the backplate.

2. The MEMS microphone according to claim 1, wherein: The connector is fixedly connected to the back plate; and the connector and the back plate are integrally formed.

3. The MEMS microphone according to claim 2, wherein: The connector includes a first connecting part and a second connecting part fixedly connected to the first connecting part. The first connecting part is fixedly connected to the back plate, and the second connecting part is fixedly connected to the isolation island.

4. The MEMS microphone according to claim 3, wherein: The cross-sectional area of ​​the first connecting part is greater than the cross-sectional area of ​​the second connecting part.

5. The MEMS microphone according to claim 3, wherein: Both the cross-section of the first connecting part and the cross-section of the second connecting part are circular.

6. The MEMS microphone according to claim 4, wherein: An air gap is formed between each of the isolation islands and the back plate.

7. The MEMS microphone according to claim 6, wherein: A connecting surface is formed at the position where the first connecting part and the second connecting part are fixedly connected; Along the vibration direction of the diaphragm, the air gap includes a first gap formed between the surface of the back plate facing the isolation island and the connecting surface, and a second gap formed between the surface of the isolation island facing the back plate and the connecting surface.

8. The MEMS microphone according to claim 1, wherein: The connector is fixedly connected to the substrate; and the connector and the substrate are integrally formed.

9. The MEMS microphone according to claim 8, wherein: The connector includes an anchor, which is fixedly connected between the isolation island and the base.

10. The MEMS microphone according to claim 9, wherein: The anchor has a cross-section with rounded corners along the vibration direction perpendicular to the diaphragm. The anchor is filled with an oxide isolation layer.

11. The MEMS microphone according to claim 1, wherein: Along the vibration direction of the diaphragm, the orthographic projection of the isolation island on the back plate covers the orthographic projection of the connector on the back plate; And / or, the orthographic projection of the isolation island on the substrate overlaps the orthographic projection of the connector on the substrate.

12. The MEMS microphone according to claim 1, wherein: Along the vibration direction of the diaphragm, the orthographic projection of the connector on the isolation island is located at the center of the isolation island.

13. The MEMS microphone according to claim 1, wherein: The beam structure is located between two adjacent gaps.

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