Diaphragm and MEMS microphone

Abstract

A diaphragm and a MEMS microphone. The diaphragm comprises a vibrating portion (1) and supporting structures (2) connected to the vibrating portion (1). Each supporting structure (2) comprises a cantilever portion (21) extending outwards from the periphery of the vibrating portion (1), and a first anchoring portion (22) and a second anchoring portion (23), both of which are connected to the end of the cantilever portion (21) away from the vibrating portion (1). The lengths of both the first anchoring portion (22) and the second anchoring portion (23) extend along the circumference of the vibrating portion (1), and the length of the first anchoring portion (22) and the length of the second anchoring portion (23) extend in opposite directions. As the lengths of both the first anchoring portion (22) and the cantilever portion (21) extend along the circumference of the vibrating portion (1), and the length of the first anchoring portions (22) and the length of the second anchoring portion (23) extend in opposite directions, the first anchoring portion (22), the cantilever portion (21), and the second anchoring portion (23) are connected to form a T shape, that is, each supporting structure is a T-shaped beam, enabling the diaphragm to have a wider range of vibration displacement, and thereby improving the sensitivity and adaptability of the MEMS microphone.

Description

A diaphragm and MEMS microphone Technical Field

[0001] The utility model belongs to the technical field of MEMS microphones, and in particular relates to a diaphragm and a MEMS microphone. Background Art

[0002] In related technologies, a MEMS microphone consists of a substrate, a backplate, and a diaphragm. The diaphragm is a key component of a MEMS microphone, typically consisting of a vibrating portion and a supporting structure connected to the vibrating portion. The supporting structure is typically designed as a cantilever beam, with one end connected to the vibrating portion and the other end anchored to the substrate or backplate. Due to the small deformation of the cantilever beam, the diaphragm's vibration displacement range is small, which in turn reduces the microphone's sensitivity.

[0003] Therefore, it is necessary to provide a new diaphragm. Technical issues

[0004] The purpose of the present invention is to provide a diaphragm and a MEMS microphone, which can solve the problem of small vibration displacement of the diaphragm in the related art. Technical Solutions

[0005] The technical solution of the utility model is as follows:

[0006] A diaphragm includes a vibrating portion and a supporting structure connected to the vibrating portion, the supporting structure including a cantilever portion extending outward from the periphery of the vibrating portion, and a first anchor portion and a second anchor portion both connected to one end of the cantilever portion away from the vibrating portion, the lengths of the first anchor portion and the second anchor portion both extending along the circumference of the vibrating portion, and the length extension direction of the first anchor portion is opposite to the length extension direction of the second anchor portion.

[0007] Preferably, the first anchoring portion has a first anchoring area, which is located at one end of the first anchoring portion away from the cantilever portion; the second anchoring portion has a second anchoring area, which is located at one end of the second anchoring portion away from the cantilever portion.

[0008] Preferably, the lengths of the first anchoring region and the second anchoring region are both within the range of 60 μm-80 μm, the width of the first anchoring region is smaller than the width of the first anchoring portion, and the width of the second anchoring region is smaller than the width of the second anchoring portion.

[0009] Preferably, a first rounded corner is formed at the connection between the cantilever portion and the first anchor portion, and a second rounded corner is formed at the connection between the cantilever portion and the second anchor portion. The radii of the first rounded corner and the second rounded corner are both within a range of 5 μm to 15 μm.

[0010] Preferably, a third rounded corner is formed at a connection between the vibration portion and the cantilever portion, and a radius of the third rounded corner is within a range of 30 μm to 60 μm.

[0011] Preferably, the length of the cantilever portion is within a range of 60 μm to 80 μm, and the width of the cantilever portion is within a range of 15 μm to 25 μm.

[0012] Preferably, the cross-section of the vibration part is circular or polygonal.

[0013] Preferably, a plurality of the supporting structures are connected to the vibration part, and the plurality of supporting structures are distributed at equal angular intervals around the central axis of the vibration part.

[0014] A MEMS microphone comprises a substrate, a back plate fixed to the substrate and having a plurality of acoustic holes, and a diaphragm as described above fixed to the substrate or the back plate, wherein the first anchoring portion and the second anchoring portion are both fixed to the substrate or the back plate.

[0015] Preferably, a plurality of protrusions are fixed to the substrate and / or the back plate, and the protrusions are in contact with the diaphragm. Beneficial effects

[0016] The beneficial effects of the present invention are as follows: because the lengths of the first and second anchoring portions both extend along the circumference of the vibrating portion, and the length extension direction of the first anchoring portion is opposite to that of the second anchoring portion, the first anchoring portion, the cantilever portion, and the second anchoring portion are connected in a T-shape, i.e., the supporting structure is a T-beam. Compared to the cantilever beam in the related art, the T-beam has a greater deformation, which increases the vibration displacement range of the diaphragm, thereby improving the sensitivity and compliance of the MEMS microphone. In addition, the support structure is provided with two anchoring portions. On the one hand, it can increase the rigidity of the diaphragm and effectively relieve the stress of the diaphragm, improving the signal-to-noise ratio and reliability, and on the other hand, it can minimize the risk of wrinkling. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG1 is a schematic structural diagram of a diaphragm according to an embodiment of the present invention;

[0018] Figure 2 is an enlarged view of detail A in Figure 1;

[0019] FIG3 is a schematic structural diagram of a MEMS microphone according to an embodiment of the present invention;

[0020] FIG4 is an exploded view of a MEMS microphone according to an embodiment of the present invention. Modes for Carrying Out the Invention

[0021] The present invention will be further described below with reference to the accompanying drawings and implementation examples.

[0022] Referring to Figures 3 and 4 , an embodiment of the present invention provides a MEMS microphone comprising a substrate 10, a backplate 20 fixed to the substrate 10 and having a plurality of acoustic holes 201, and a diaphragm 30 fixed to the substrate 10 or the backplate 20. Specifically, the substrate 10 is provided with a receiving cavity 101, within which the backplate 20 is fixed. The acoustic holes 201 provided on the backplate 20 are used to conduct sound and balance sound pressure. The diaphragm 30 is fixed to the substrate 10 and is located on one side of the backplate 20. The diaphragm 30 and the backplate 20 form a capacitor structure. It should be understood that when in operation, the diaphragm 30 deforms under the action of sound pressure, causing the capacitance of the electric field between the diaphragm 30 and the backplate 20 to change. This capacitance change reflects the magnitude of the sound pressure. Since the backplate 20 does not deform, the vibration displacement of the diaphragm 30 directly affects the capacitance, thereby affecting the sensitivity of the microphone.

[0023] Please refer to Figures 1 and 2. The diaphragm 30 includes a vibration part 1 and a supporting structure 2 connected to the vibration part 1. The supporting structure 2 includes a cantilever part 21 extending outward from the outer periphery of the vibration part 1, and a first anchoring part 22 and a second anchoring part 23 both connected to an end of the cantilever part 21 away from the vibration part 1. The lengths of the first anchoring part 22 and the second anchoring part 23 both extend along the circumference of the vibration part 1, and the length extension direction of the first anchoring part 22 is opposite to the length extension direction of the second anchoring part 23.

[0024] Because the lengths of the first anchoring portion 22 and the second anchoring portion 23 both extend along the circumference of the vibrating portion 1, and the length extension direction of the first anchoring portion 22 is opposite to that of the second anchoring portion 23, the first anchoring portion 22, the cantilever portion 21, and the second anchoring portion 23 are connected in a T-shape, that is, the support structure 2 is a T-beam. Compared with the cantilever beam in the related art, the T-beam has a larger deformation, which increases the vibration displacement range of the diaphragm 30, thereby improving the sensitivity and compliance of the MEMS microphone. In addition, the provision of two anchoring portions in the support structure 2 can, on the one hand, increase the rigidity of the diaphragm 30 and effectively relieve the stress of the diaphragm 30, thereby improving the signal-to-noise ratio and reliability, and on the other hand, minimize the risk of wrinkling.

[0025] It should be noted that the first anchor portion 22 and the second anchor portion 23 are symmetrically arranged with the cantilever portion 21 as the axis of symmetry. Moreover, by increasing the stiffness of the support structure 2 through the relevant parameters of the first anchor portion 22, the second anchor portion 23, and the cantilever portion 21, not only a high signal-to-noise ratio can be achieved, but also robustness can be improved.

[0026] Referring to Figures 3 and 4 , in some embodiments, the first anchor portion 22 and the second anchor portion 23 are both fixed to the substrate 10 or the backplate 20. Multiple protrusions 40 are fixed to the substrate 10 and / or the backplate 20. The protrusions 40 contact the diaphragm 30, thereby preventing adhesion between the diaphragm 30 and the substrate 10, and between the diaphragm 30 and the backplate 20, thereby improving the sensitivity of the MEMS microphone. In one embodiment, the first anchor portion 22 and the second anchor portion 23 are both fixed to the substrate 10. Multiple protrusions 40 are fixed to the substrate 10. The multiple protrusions 40 contact the cantilever portion 21, the first anchor portion 22, and the second anchor portion 23, respectively.

[0027] Please refer to Figure 2. The first anchoring portion 22 has a first anchoring area 221, which is located at the end of the first anchoring portion 22 away from the cantilever portion 21, that is, the length of the first anchoring area 221 is less than the length of the first anchoring portion 22; the second anchoring portion 23 has a second anchoring area 231, which is located at the end of the second anchoring portion 23 away from the cantilever portion 21, that is, the length of the second anchoring area 231 is less than the length of the second anchoring portion 23, which is beneficial to ensure that the T-beam has a larger deformation amount than the cantilever beam in the related art.

[0028] In one embodiment, the lengths of the first anchoring region 221 and the second anchoring region 231 are both within the range of 60 μm-80 μm, such as 60 μm, 65 μm, 70 μm, 75 μm and 80 μm, etc., preferably 70 μm. The width of the first anchoring region 221 is smaller than the width of the first anchoring portion 22, and the width of the second anchoring region 231 is smaller than the width of the second anchoring portion 23. For example, the widths of the first anchoring portion 22 and the second anchoring portion 23 are 19 μm, and the widths of the first anchoring region 221 and the second anchoring region 231 are 14 μm, so that the T-shaped support structure 2 simultaneously satisfies certain stiffness and deformation.

[0029] Please refer to Figure 2. A first rounded corner R1 is formed at the connection between the cantilever portion 21 and the first anchor portion 22, and a second rounded corner R2 is formed at the connection between the cantilever portion 21 and the second anchor portion 23. The radii of the first rounded corner R1 and the second rounded corner R2 are both within the range of 5μm-15μm, such as 5μm, 8μm, 10μm, 12μm, 14μm and 15μm, and are preferably 10μm. A third rounded corner R3 is formed at the connection between the vibrating portion 1 and the cantilever portion 21. The radius of the third rounded corner R3 is within the range of 30μm-60μm, such as 30μm, 35μm, 40μm, 45μm, 50μm and 60μm, and are preferably 45μm. The rounded corner design can not only increase the sensitivity of the MEMS microphone by increasing the area of ​​the diaphragm 30, but also prevent the stress at the connection where the rounded corner is located from being too concentrated and affecting the reliability of the MEMS microphone.

[0030] The width of the cantilever portion 21 is greater than the width of the first anchor portion 22 and the second anchor portion 23, and the length of the cantilever portion 21 is less than the length of the first anchor portion 22 and the second anchor portion 23; the length of the cantilever portion 21 is within 60μm-80μm, for example, 60μm, 65μm, 70μm, 75μm and 80μm, etc., preferably 70μm; the width of the cantilever portion 21 is within 15μm-25μm, for example, 15μm, 18μm, 20μm, 22μm and 25μm, etc., preferably 22μm. The larger the length and width of the cantilever portion 21, the greater the flexibility of the T-shaped support structure 2.

[0031] It should be noted that the stiffness (flexibility) of the T-shaped support structure 2 can be changed by modifying the length and width of the first anchoring portion 22, the second anchoring portion 23 and the cantilever portion 21, the size and shape of the first anchoring area 221 and the second anchoring area 231, and the size of the first rounded corner R1, the second rounded corner R2 and the third rounded corner R3. For example, a small-sized first anchoring area 221 and the second anchoring area 231 and a longer cantilever portion 21 can increase the flexibility of the T-shaped support structure 2 and reduce the introduced voltage.

[0032] Please refer to Figure 1. The cross-sectional shape of the vibration part 1 is circular or polygonal, and the multiple deformations can be quadrilateral, pentagon, hexagon and octagon, etc., preferably octagon. Multiple support structures 2 are connected to the vibration part 1, and the multiple support structures 2 are distributed at equal angles around the central axis of the vibration part 1. There are eight support structures 2, and the eight support structures 2 are arranged at the eight corners of the octagonal vibration part 1, which is beneficial to improving the stability of the vibration of the diaphragm 30.

[0033] The above is only an embodiment of the present invention. It should be pointed out that those skilled in the art can make improvements without departing from the inventive concept of the present invention, but these improvements are all within the scope of protection of the present invention.

Claims

1. A diaphragm, comprising a vibrating portion and a supporting structure connected to the vibrating portion, characterized in that: The supporting structure includes a cantilever portion extending outward from the periphery of the vibration portion, and a first anchor portion and a second anchor portion both connected to one end of the cantilever portion away from the vibration portion, the lengths of the first anchor portion and the second anchor portion both extend along the circumference of the vibration portion, and the length extension direction of the first anchor portion is opposite to the length extension direction of the second anchor portion.

2. The diaphragm according to claim 1, characterized in that: The first anchoring portion has a first anchoring region, which is located at one end of the first anchoring portion away from the cantilever portion; the second anchoring portion has a second anchoring region, which is located at one end of the second anchoring portion away from the cantilever portion.

3. The diaphragm according to claim 2, characterized in that: The lengths of the first anchoring region and the second anchoring region are both within a range of 60 μm-80 μm, and the width of the first anchoring region is smaller than the width of the first anchoring portion, and the width of the second anchoring region is smaller than the width of the second anchoring portion.

4. The diaphragm according to claim 1, characterized in that: A first rounded corner is formed at a connection between the cantilever portion and the first anchor portion, and a second rounded corner is formed at a connection between the cantilever portion and the second anchor portion. The radii of the first rounded corner and the second rounded corner are both within a range of 5 μm to 15 μm.

5. The diaphragm according to claim 1, characterized in that: A third fillet is formed at a connection between the vibration portion and the cantilever portion, and a radius of the third fillet is within a range of 30 μm to 60 μm.

6. The diaphragm according to claim 1, characterized in that: The length of the cantilever portion is within a range of 60 μm to 80 μm, and the width of the cantilever portion is within a range of 15 μm to 25 μm.

7. The diaphragm according to claim 1, characterized in that: The cross-sectional shape of the vibration part is circular or polygonal.

8. The diaphragm according to claim 1, characterized in that: A plurality of the supporting structures are connected to the vibration part, and the plurality of the supporting structures are distributed at equal angles around a central axis of the vibration part.

9. A MEMS microphone, comprising a substrate, a back plate fixed to the substrate and having a plurality of acoustic holes, and a diaphragm according to any one of claims 1 to 8 fixed to the substrate or the back plate, characterized in that: The first anchoring portion and the second anchoring portion are both fixed to the substrate or the back plate.

10. The MEMS microphone according to claim 9, characterized in that: A plurality of protrusions are fixed to the substrate and / or the back plate, and the protrusions are in contact with the diaphragm.

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