Microphone chips and MEMS microphones

Abstract

This invention discloses a microphone chip and a MEMS microphone. The microphone chip comprises: a chip structure comprising a semiconductor substrate, a backplate and a diaphragm disposed oppositely thereto; and a dustproof structure disposed above the backplate and at least partially shielding the opening of the backplate. Consequently, the microphone chip according to embodiments of the present invention has a low failure rate, a long service life, and high sensitivity.

Description

Technical Field

[0001] The present invention relates to the technical field of microphones, and in particular to a microphone chip and a MEMS microphone. Background Art

[0002] For microphones, after the chip is made through the MEMS process, during transportation, packaging and normal use, dust and other pollutant particles floating in the air will fall on the back plate of the microphone, and enter between the back plate and the diaphragm through the sound holes on the back plate, causing the diaphragm to be unable to vibrate normally, causing the microphone chip to fail. This is currently the most common failure mode. In the related art, during the packaging process of the microphone, a mesh membrane is pasted at the sound inlet of the microphone to filter out dust and other pollutant particles in the air. However, this structure has no way to prevent the microphone chip from being contaminated by particles before packaging and during transportation, and during use, the mesh membrane is easy to fall off, causing the microphone to fail. Summary of the Invention

[0003] An object of the present invention is to provide a microphone chip that can prevent contamination particles from entering between the diaphragm and the back plate, thereby reducing particle contamination and lowering failure rate.

[0004] In order to solve the above technical problems, the present invention provides a microphone chip.

[0005] According to an embodiment of the present invention, the microphone chip includes: a chip structure, which includes a semiconductor substrate and a back plate and a diaphragm arranged opposite to each other on the semiconductor substrate; and a dustproof structure, which is arranged above the back plate and at least partially blocks the opening area of ​​the back plate.

[0006] Therefore, the microphone chip according to the embodiment of the present invention, by providing a dust-proof structure, can prevent polluted particles in the environment from falling between the back plate and the diaphragm during transportation, packaging and normal use, thereby avoiding affecting the normal vibration of the diaphragm, thereby reducing the failure rate of the microphone chip, increasing the service life of the microphone chip, reducing costs, and also improving the sensitivity of the microphone chip.

[0007] According to some embodiments of the present invention, the dust-proof structure includes a shielding plate and a supporting portion, wherein the shielding plate is spaced apart from the back plate in the up and down directions and exposes the electrode connection portion of the chip structure, and the supporting portion is connected and supported between the back plate and the shielding plate.

[0008] Optionally, the shielding plate shields the opening area of ​​the back plate.

[0009] Optionally, the shielding plate corresponds to the shape of the opening area of ​​the back plate to cover the opening area of ​​the back plate.

[0010] Furthermore, the shielding plate is formed in a circular shape.

[0011] Optionally, the shielding plate is formed with a notch exposing the electrode connecting portion.

[0012] Optionally, the shielding plate is formed with a through hole corresponding to the electrode connecting portion to expose the electrode connecting portion.

[0013] Optionally, the support portion includes a plurality of support members spaced apart along the circumference of the shielding plate, and the plurality of support members surround the opening area of ​​the back plate.

[0014] Furthermore, the support member is formed in a column shape.

[0015] Optionally, the support member is formed in a plate shape surrounding the opening area of ​​the back plate to shield the opening area at the side of the opening area.

[0016] Optionally, the support member is formed as an outwardly protruding arc-shaped plate.

[0017] Optionally, the support member is provided at a corner of the back plate and extends along the corner shape of the back plate to surround the opening area.

[0018] Optionally, the dustproof structure further includes a blocking portion, which is provided on the support member and between adjacent support members.

[0019] Optionally, a blocking portion is formed between any adjacent support members.

[0020] Optionally, the blocking member is formed as a blocking plate.

[0021] Optionally, the blocking portion includes a first blocking member and a second blocking member, the first blocking member and the second blocking member are respectively arranged on adjacent support members, the first blocking member and the second blocking member are spaced apart and at least partially overlap in a direction surrounding the opening area.

[0022] Furthermore, the first blocking member and the second blocking member are respectively formed in a plate shape, the first blocking member extends obliquely toward the opening area, and the second blocking member is arranged on the outside of the first blocking member and extends obliquely toward a direction away from the opening area.

[0023] Optionally, the support portion and the shielding plate are integrally formed.

[0024] The present invention also provides a MEMS microphone.

[0025] A MEMS microphone according to an embodiment of the present invention includes the microphone chip of the above embodiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic structural diagram of a microphone chip according to an embodiment of the present invention;

[0027] Figure 2 is a schematic cross-sectional view of a support portion of a microphone chip according to an embodiment of the present invention;

[0028] Figure 3 is a schematic structural diagram of a microphone chip according to another embodiment of the present invention;

[0029] Figure 4 is a schematic cross-sectional view of a supporting portion of a microphone chip according to another embodiment of the present invention;

[0030] Figure 5 is a schematic cross-sectional view of a support portion of a microphone chip according to yet another embodiment of the present invention;

[0031] Figure 6 is a schematic cross-sectional view of a support portion of a microphone chip according to yet another embodiment of the present invention;

[0032] Figure 7 is a structural diagram of a microphone chip according to another embodiment of the present invention;

[0033] Figure 8 is a schematic cross-sectional view of a support portion of a microphone chip according to yet another embodiment of the present invention;

[0034] Figure 9 is a schematic cross-sectional view of a support portion of a microphone chip according to yet another embodiment of the present invention;

[0035] Figure 10 yes Figure 9 Enlarged view of part A in the middle;

[0036] Figure 11 is a schematic cross-sectional view of a support portion of a microphone chip according to yet another embodiment of the present invention;

[0037] Figure 12 yes Figure 11 Enlarged view of part B in the middle.

[0038] Reference numerals:

[0039] 100: microphone chip;

[0040] 1: semiconductor substrate, 11: silicon substrate, 12: first sacrificial layer, 13: second sacrificial layer,

[0041] 14: diaphragm;

[0042] 2: Chip structure, 21: Back plate, 22: Opening area;

[0043] 3: dustproof structure, 31: shielding plate, 311: notch, 312: through hole, 32: support part,

[0044] 33: Support member, 34: Blocking portion, 35: First blocking member, 36: Second blocking member. DETAILED DESCRIPTION

[0045] The microphone chip proposed by the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] The microphone chip 100 according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0047] Combine Figure 1 、 Figure 3 as well as Figure 7 As shown, the microphone chip 100 according to an embodiment of the present invention includes a chip structure 2 and a dustproof structure 3. The chip structure 2 includes a semiconductor substrate 1 and a back plate 21 and a diaphragm 14 formed on the semiconductor substrate 1 and arranged opposite to each other. Specifically, the diaphragm 14 is formed in the semiconductor substrate 1. The diaphragm 14 is in the semiconductor substrate 1 and a cavity is formed between the back plate 21 and the diaphragm 14. An opening area 22 connected to the cavity is formed on the back plate 21. In this way, the air vibration generated by the sound is transmitted to the vibration cavity through the opening area 22 and to the diaphragm 14, so that the distance between the diaphragm 14 and the back plate 21 changes, and then the capacitance formed by the back plate 21 and the diaphragm 14 changes, thereby realizing the conversion of the sound signal into an electrical signal.

[0048] The dustproof structure 3 is arranged above the back pole plate 21 and at least partially blocks the opening area 22 of the back pole plate 21, that is, the dustproof structure 3 is formed above the opening area 22 of the back pole plate 21, and the dustproof structure 3 can block at least a part of the opening area 22 of the back pole plate 21. Preferably, the dustproof structure 3 can completely block the opening area 22 of the back pole plate 21. In this way, by blocking the opening area 22 through the dustproof structure 3, dust particles in the air can be prevented from falling on the back pole plate 21 and the diaphragm 14, thereby avoiding the back pole plate 21 and the diaphragm 14 from failing to work normally due to the entry of contamination particles between the back pole plate 21 and the diaphragm 14, and thus avoiding the resulting failure of the microphone chip 100.

[0049] Therefore, the microphone chip 100 according to the embodiment of the present invention can prevent polluted particles in the environment from falling onto the back plate 21 and the diaphragm 14 during transportation, packaging and normal use by providing a dustproof structure 3, thereby affecting the normal movement of the diaphragm. This can reduce the failure rate of the microphone chip 100, increase the service life of the microphone chip 100, reduce costs, and also improve the sensitivity of the microphone chip 100.

[0050] like Figure 1 、 Figure 3 as well as Figure 7 As shown, the semiconductor substrate 1 may include a stacked silicon substrate 11, a first sacrificial layer 12 and a second sacrificial layer 13, a diaphragm 14 is formed between the first sacrificial layer 12 and the second sacrificial layer 13, a back plate 21 is formed on the upper surface of the second sacrificial layer 13, an opening area 22 corresponding to the diaphragm 14 is formed on the back plate 21, and a dustproof structure 3 is formed above the back plate 21.

[0051] Combine Figures 1-8 As shown, the dustproof structure 3 may include a shielding plate 31 and a supporting portion 32. The shielding plate 31 is arranged above the back plate 21 and is spaced apart from the back plate 21 in the up and down directions, and exposes the electrode connecting portion of the chip structure 2. In this way, the shielding plate 31 can prevent contamination particles from entering between the back plate 21 and the diaphragm 14, and the shielding plate 31 does not block the electrode connecting portion of the chip structure 2, that is, the electrode connecting portion of the chip structure 2 is exposed to the shielding plate 31, thereby facilitating the electrical connection of the electrode connecting portion of the chip structure 2.

[0052] The support portion 32 is connected and supported between the chip structure 2 and the baffle plate 31. This not only enables support and fixation between the baffle plate 31 and the chip structure 2, but also supports the baffle plate 31 through the support portion 32, separating the baffle plate 31 from the back plate 21 on the chip structure 2, and also facilitates the transmission of sound to the diaphragm 14 through the air. Furthermore, the support portion 32 can also prevent contamination particles from entering between the back plate 21 and the diaphragm 14 from the side, so as to further improve the effect of particle contamination and improve the sensitivity of the microphone chip 100.

[0053] Alternatively, as Figure 1 As shown, the support portion 32 can be connected between the back plate 21 and the shielding plate 31, that is, the lower end of the support portion 32 is connected to the back plate 21 so as to surround the opening area 22 of the back plate 21, not only shielding the opening area 22, but also making the structure volume of the microphone chip 100 relatively small. Figure 3 As shown, the support portion 32 can be connected and supported on the upper surface of the chip structure 2 and is not connected to the back plate 21. For example, the support portion 32 can be supported and connected on other structures on the surface of the chip structure 2, as long as it can support the shielding plate 31 that shields the back plate 21.

[0054] Optionally, the support portion 32 and the shielding plate 31 are integrally formed, so that the support portion 32 and the shielding plate 31 are an integrated structure, which can not only enhance the structural strength of the dustproof structure 3 but also simplify the molding process of the shielding plate 31 and the support portion 32.

[0055] In some embodiments of the present invention, the shielding plate 31 shields the opening area 22 of the back plate 21, such as Figure 1 、 Figure 3 as well as Figure 7 As shown, the shielding plate 31 is arranged above the back pole plate 21 and parallel to the back pole plate 21. The shielding plate 31 can completely block the opening area 22 of the back pole plate 21, which can further prevent the contamination particles from falling from the opening area 22 into between the back pole plate 21 and the diaphragm 14, thereby improving the effect of the shielding plate 31 in preventing particle contamination from causing the diaphragm 14 to fail to work.

[0056] In some specific examples of the present invention, the shielding plate 31 corresponds to the shape of the opening area 22 of the back plate 21 to cover the opening area 22 of the back plate 21. That is, the shape of the shielding plate 31 matches the shape of the back plate 21, and the shielding plate 31 can completely block the opening area 22 of the back plate 21, and the shielding plate 31 does not block the electrode connection portion of the chip structure 2. Figure 1 As shown, the opening area 22 of the back plate 21 is formed in a circular shape, and the shielding plate 31 is formed in a circular shape and is arranged above the opening area 22 of the back plate 21 to completely cover the opening area 22 of the back plate 21 .

[0057] In other examples of the present invention, the shielding plate 31 can also be formed into other shapes, for example, the shielding plate 31 can be formed into a polygon or a square, a rectangle, etc., or the shielding plate 31 can be formed into an irregular shape. The present invention does not make any special limitations on this, as long as it can block the opening area 22 of the back plate 21.

[0058] Optionally, the shape of the shielding plate 31 may correspond to the shape of the backpolar plate 21, that is, the shape of the shielding plate 31 is substantially the same as that of the backpolar plate 21. For example, the backpolar plate 21 is formed into a square, and the shielding plate 31 may also be formed into a square and shield the upper surface of the backpolar plate 21. Thus, the shielding plate 31 has a simple structure and is convenient for shielding the opening area 22 of the backpolar plate 21. A notch 311 corresponding to the electrode connecting portion of the chip structure 2 may be formed on the shielding plate 31. In this way, the electrode connecting portion can be exposed through the notch 311 to facilitate electrical connection with other components.

[0059] Alternatively, as Figure 3 As shown, the shape of the shielding plate 31 is adapted to the shape of the back plate 21 and completely covers the upper surface of the back plate 21. A through hole 312 corresponding to the electrode connecting part is formed on the shielding plate 31 to expose the electrode connecting part. The through hole 312 facilitates the electrical connection between the electrode connecting part and other components, and can also further expand the shielding area of ​​the shielding plate 31 and reduce the falling of pollution particles.

[0060] Regarding the support portion 32, the support portion 32 may be vertically connected between the shielding plate 31 and the back plate 21 to support the shielding plate 31. Figures 1-9 as well as Figure 11As shown, the support portion 32 may include a plurality of support members 33 spaced apart along the circumference of the shielding plate 31, and the plurality of support members 33 are arranged around the opening area 22 of the back plate 21. Optionally, the plurality of support members 33 may be spaced apart evenly along the circumference of the shielding plate 31, which can make the structure of the microphone chip 100 more stable. Figure 5 、 Figure 7 and Figure 8 As shown, the multiple support members 33 can be formed into a column shape, that is, each support member 33 can be formed into a support column, and the arrangement, quantity and height of the multiple support columns can be adjusted and selected according to actual conditions.

[0061] In other examples of the present invention, Figures 1-4 as well as Figure 6 As shown, the support member 33 can be formed into a plate shape to shield the opening area 22 on the side of the opening area 22. In other words, the support member 33 can be formed into a support plate, which can shield the back pole plate 21 from the side to shield the back pole plate 21 from the side, which can not only improve the effect of preventing the diaphragm 14 from malfunctioning due to particle contamination, but also enhance the supporting effect of the support part 32, the back pole plate 21 and the shielding plate 31.

[0062] like Figure 1 and Figure 2 As shown, the support member 33 can be formed as an outwardly protruding arc-shaped plate, and a plurality of support members 33 are arranged at intervals around the opening area 22 of the back plate 21. Figure 6 As shown, the support member 33 is formed as a flat plate, the width direction of the flat plate is consistent with the width direction of the edge of the back plate 21. Figure 3 and Figure 4 As shown, the support members 33 can be arranged at the corners of the back plate 21, and each support member 33 is formed into a plate-like structure, and the plate-like structure of each support member 33 is adapted to the corner shape of the back plate 21, for example, the cross-section of the support member 33 is formed into a semi-enclosed structure with the same corner shape.

[0063] In such Figure 1 and Figure 2 In the example shown, the shielding plate 31 is formed into a circle, and the support member 33 is formed into a columnar shape. There may be four support members 33, and the four support members 33 are evenly spaced and distributed along the circumference of the shielding plate 31. Figure 3 and Figure 4 In the example shown, the shielding plate 31 can be formed into a square shape and corresponds to the shape of the back plate 21. A plurality of support members 33 are provided at the edges of the shielding plate 31 and the back plate 21 and arranged along the extending direction of the four sides of the shielding plate 31 and the back plate 21. For example, there can be four support members 33, and the four support members 33 can be respectively provided at the four corners of the shielding plate 31. Figure 8In the example shown, the shielding plate 31 is provided with a notch 311 corresponding to the electrode connection portion, and there may be six support members 33 , which are spaced apart and arranged along the edge shape of the shielding plate 31 .

[0064] In some embodiments of the present invention, Figures 9-12 As shown, the dust-proof structure 3 may further include a blocking portion 34, which is arranged on the support member 33 and between adjacent support members 33. The adjacent support members 33 are spaced apart and have a certain spacing gap. The blocking portion 34 is formed on the side of the support member 33 facing the spacing gap. In this way, the blocking portion 34 can enter from the spacing gap between the support members 33 through the blocking portion 34 and fall to the back plate 21.

[0065] Preferably, a barrier 34 is formed between any two adjacent support members 33. That is, the gap between any two adjacent support members 33 is provided with a barrier 34, thereby further improving the effect of preventing particle contamination. Optionally, the barrier 34 can be formed as a barrier plate, thereby further increasing the blocking area and improving the effect of preventing particle contamination.

[0066] In some embodiments of the present invention, Figure 10 and Figure 12 As shown, the blocking portion 34 may include a first blocking member 35 and a second blocking member 36, each of which is disposed on adjacent support members 33 and spaced apart from each other. In other words, the first blocking member 35 and the second blocking member 36 together constitute the blocking portion 34, with the first blocking member 35 disposed on one of the two adjacent support members 33 and the second blocking member 36 disposed on the other of the two adjacent support members 33. The first blocking member 35 and the second blocking member 36 are both disposed between the two adjacent support members 33 and spaced apart from each other. Thus, the provision of the first blocking member 35 and the second blocking member 36 not only improves the particle contamination prevention effect, but also creates a certain spacing between the first blocking member 35 and the second blocking member 36 to allow sound to be transmitted to the diaphragm 14 through air vibration. Furthermore, during the preparation process of the microphone chip 100, the etching solution is allowed to flow into the semiconductor substrate 1 to form the chip structure 2.

[0067] like Figure 10 and Figure 9As shown, the first barrier 35 and the second barrier 36 are respectively formed on one side of the support member 33 facing the adjacent support member 33, wherein the first barrier 35 and the second barrier 36 are arranged opposite to each other, and the first barrier 35 and the second barrier 36 are spaced apart in the width direction of the spacing gap between adjacent support members 33. At this time, the first barrier 35 and the second barrier 36 cover a part of the width direction of the spacing gap between adjacent support members 33, so that the first barrier 35 and the second barrier 36 can further prevent particle contamination from the side.

[0068] like Figure 11 and Figure 12 As shown, the first barrier 35 and the second barrier 36 can be formed into a plate shape. Optionally, the first barrier 35 and the second barrier 36 at least partially overlap in the direction surrounding the opening area 22, that is, the first barrier 35 and the second barrier 36 cover the width of the spacing gap between adjacent supports 33. The first barrier 35 and the second barrier 36 can completely block the spacing gap in the width direction of the spacing gap between adjacent supports 33, thereby improving the effect of preventing particle contamination on the side, wherein the first barrier 35 and the second barrier 36 are arranged in a spaced-apart manner in the length direction of the spacing gap between adjacent supports 33.

[0069] In such Figure 11 and Figure 12 In the example shown, the second blocking member 36 is arranged on the outside of the first blocking member 35, the first blocking member 35 is formed as an inclined plate extending obliquely toward the direction where the opening area 22 is located, and the second blocking member 36 is formed as an inclined plate extending obliquely toward a direction away from the opening area 22. The first blocking member 35 and the second blocking member 36 are arranged in parallel and partially overlap.

[0070] The present invention further provides a MEMS microphone, which includes the microphone chip 100 of the above embodiment.

[0071] Therefore, the MEMS microphone according to the embodiment of the present invention can avoid the diaphragm 14 from malfunctioning due to contamination particles entering between the back plate 21 and the diaphragm 14 by providing the microphone chip 100 of the above embodiment, thereby improving the sensitivity of the MEMS microphone. In addition, the failure rate of the microphone chip 100 of the above embodiment is low, which can also increase the service life of the MEMS microphone and reduce costs.

[0072] The above description is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A microphone chip, characterized in that: include: A chip structure comprising a semiconductor substrate and a back plate and a diaphragm disposed opposite to each other on the semiconductor substrate; A dustproof structure, the dustproof structure is arranged above the back plate and at least partially blocks the opening area of ​​the back plate, the dustproof structure includes a shielding plate and a support portion, the shielding plate blocks the opening area of ​​the back plate, the shielding plate and the back plate are spaced apart in the vertical direction, the support portion is connected and supported between the chip structure and the shielding plate, the support portion includes a plurality of support members spaced apart along the circumference of the shielding plate, and sound enters the opening area through the gaps between the support members; A blocking portion is provided on the support member and between adjacent support members, the blocking portion includes a first blocking member and a second blocking member, the first blocking member and the second blocking member are respectively provided on adjacent support members and are spaced apart, and the first blocking member and the second blocking member at least partially overlap in a direction surrounding the opening area.

2. The microphone chip according to claim 1, characterized in that The shielding plate exposes the electrode connecting portion of the chip structure.

3. The microphone chip according to claim 1, wherein: The shielding plate has a shape corresponding to the opening area of ​​the back plate so as to cover the opening area of ​​the back plate.

4. The microphone chip according to claim 3, characterized in that The shielding plate is formed in a circular shape.

5. The microphone chip according to claim 2, characterized in that: The shielding plate is formed with a notch exposing the electrode connecting portion.

6. The microphone chip according to claim 2, characterized in that The shielding plate is formed with a through hole corresponding to the electrode connecting portion to expose the electrode connecting portion.

7. The microphone chip according to claim 3, characterized in that A plurality of support members surround the opening area of ​​the back plate.

8. The microphone chip according to claim 7, characterized in that: The support member is formed in a column shape.

9. The microphone chip according to claim 7, characterized in that: The support member is formed in a plate shape surrounding the opening area of ​​the back plate to shield the opening area at a side of the opening area.

10. The microphone chip according to claim 9, characterized in that: The support member is formed as an outwardly convex arc plate.

11. The microphone chip according to claim 9, characterized in that The support member is disposed at a corner of the back plate and extends along the corner shape of the back plate to surround the opening area.

12. The microphone chip according to claim 1, wherein: A blocking portion is formed between any adjacent support members.

13. The microphone chip according to claim 1, wherein: The first blocking member and the second blocking member are respectively formed in a plate shape. The first blocking member extends obliquely toward the opening area, and the second blocking member is provided on the outside of the first blocking member and extends obliquely toward a direction away from the opening area.

14. The microphone chip according to claim 1, wherein: The support portion and the shielding plate are integrally formed.

15. A MEMS microphone, characterized in that: The microphone chip comprises the microphone chip according to any one of claims 1-14.

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