Micro-electro-mechanical system and electro-mechanical conversion device

Abstract

The invention provides a micro-electro-mechanical system and an electro-mechanical conversion device.The micro-electro-mechanical system comprises a first corrugated film, a second corrugated film, a spacing structure, a first electrode, a second electrode and a compression layer, the first corrugated film and the second corrugated film are oppositely arranged in the first direction, and the spacing structure is arranged between the first corrugated film and the second corrugated film in the first direction; in the first direction, the first electrode is arranged on the side, away from the interval structure, of the first corrugated film, the second electrode is arranged on the side, away from the interval structure, of the second corrugated film, the compression layer is arranged between the first electrode and the first corrugated film, and / or the compression layer is arranged between the second electrode and the second corrugated film, and the compression layer has compression stress. And the acoustic flexibility of the micro electro mechanical system is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electromechanical conversion devices, and particularly relates to a micro-electro-mechanical system and an electromechanical conversion device. BACKGROUND

[0002] The micro-electro-mechanical system comprises a first corrugated film and a second corrugated film arranged opposite to each other, the first corrugated film and the second corrugated film are fixed and supported by a spacing structure, a first electrode is arranged on a side of the first corrugated film away from the second corrugated film, and a second electrode is arranged on a side of the second corrugated film away from the first corrugated film. In the prior art, the first electrode is directly attached to the surface of the first corrugated film, and the second electrode is directly attached to the surface of the second corrugated film. Since the first electrode, the first corrugated film, the second electrode and the second corrugated film have tensile stress due to their material properties, and the stress control of the tensile stress material is relatively difficult, the stress limit is relatively low, and therefore the acoustic compliance of the micro-electro-mechanical system is difficult to improve.

[0003] Therefore, it is necessary to provide a micro-electro-mechanical system and an electromechanical conversion device with high acoustic compliance. SUMMARY

[0004] The present application relates to the technical field of electromechanical conversion devices, and particularly relates to a micro-electro-mechanical system and an electromechanical conversion device.

[0005] The technical scheme of the present application is as follows:

[0006] The first aspect of the present application provides a micro-electro-mechanical system, which comprises a first corrugated film, a second corrugated film, a spacing structure, a first electrode, a second electrode and a compression layer. The first corrugated film and the second corrugated film are arranged opposite to each other along a first direction. Along the first direction, the spacing structure is arranged between the first corrugated film and the second corrugated film. Along the first direction, the first electrode is arranged on a side of the first corrugated film away from the spacing structure, and the second electrode is arranged on a side of the second corrugated film away from the spacing structure. The compression layer is arranged between the first electrode and the first corrugated film, and / or the compression layer is arranged between the second electrode and the second corrugated film. The compression layer has a compression stress.

[0007] In a possible design, the first corrugated film is a non-conductive film, and the second corrugated film is a non-conductive film. Alternatively, the first corrugated film is a conductive film, and the second corrugated film is a conductive film.

[0008] In a possible design, the compression stress of the material of the compression layer is greater than or equal to 30 MPa.

[0009] In a possible design, the material of the compression layer is silicon dioxide.

[0010] In a possible design, the micro-electro-mechanical system further comprises a protective wall, which covers the exposed surface of the compression layer.

[0011] In a possible design, the material of the protection wall is silicon nitride or polysilicon.

[0012] In a possible design, a part of the first electrode extends towards the first corrugated film in the first direction, and a part of the second electrode extends towards the second corrugated film in the first direction, so as to form the protection wall; or, a part of the first corrugated film extends towards the first electrode in the first direction, and a part of the second corrugated film extends towards the second electrode in the first direction, so as to form the protection wall.

[0013] In a possible design, the first corrugated film comprises a plurality of first peaks and first valleys arranged alternately, and the second corrugated film comprises a plurality of second valleys and second peaks arranged alternately, the second valley is opposite to the first peak in the first direction, and the second peak is opposite to the first valley in the first direction; in the first direction, the spacing structure is arranged between the second peak and the first valley, the first electrode is located on a side of the first peak away from the second valley, and the second electrode is located on a side of the second valley away from the first peak.

[0014] In a possible design, the spacing structure comprises a support wall, two ends of the support wall are connected with the first valley and the second peak in the first direction respectively, and at least two support walls are arranged at intervals between the first valley and the second peak in the second direction; in the second direction, a space is formed between adjacent support walls. The spacing structure further comprises a filler, and the filler is used for filling the space.

[0015] The second aspect of the present application provides a micro-electro-mechanical system, which comprises a first corrugated film, a second corrugated film, a spacing structure, a first electrode, a second electrode and a compression layer. The first corrugated film and the second corrugated film are arranged opposite to each other in the first direction. In the first direction, the spacing structure is arranged between the first corrugated film and the second corrugated film. In the first direction, the first electrode is arranged on a side of the first corrugated film away from the spacing structure, and the second electrode is arranged on a side of the second corrugated film away from the spacing structure. The compression layer is arranged between the first electrode and the first corrugated film, and / or the compression layer is arranged between the second electrode and the second corrugated film. The compression layer has a compression stress.

[0016] The present application has the beneficial effect that: the compression layer with a compression stress is arranged between the first electrode and the first corrugated film and between the second electrode and the second corrugated film, so that the flexibility of the overall structure of the micro-electro-mechanical system is improved, the acoustic compliance of the micro-electro-mechanical system and the electromechanical conversion device is improved, and the sensitivity of the electromechanical conversion device is improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 Part of the structure schematic diagram of the micro-electro-mechanical system provided by the present application in an embodiment;

[0018] Figure 2 Part structure schematic diagram of micro-electro-mechanical system provided by the present application in another embodiment;

[0019] Figure 3 Part structure schematic diagram of micro-electro-mechanical system provided by the present application in another embodiment;

[0020] Figure 4 Part structure schematic diagram of micro-electro-mechanical system provided by the present application in another embodiment.

[0021] Reference signs:

[0022] 1-first corrugated film; 11-first peak; 12-first valley; 2-second corrugated film; 21-second valley; 22-second peak; 3-spacing structure; 31-supporting wall; 32-space; 33-filler; 4-first electrode; 5-second electrode; 6-compression layer; 7-chamber; 8-protection wall. DETAILED DESCRIPTION

[0023] The present application will be further described below in conjunction with the drawings and embodiments.

[0024] The first aspect of the embodiments of the present application provides a micro-electro-mechanical system, such as Figure 1 As shown in the figure, the micro-electro-mechanical system comprises a first corrugated film 1 and a second corrugated film 2 arranged opposite along a first direction Z, and a spacing structure 3 is arranged between the first corrugated film 1 and the second corrugated film 2.

[0025] The first corrugated film 1 can be a non-conductive film, and the first corrugated film 1 can also be a conductive film.

[0026] The second corrugated film 2 can be a non-conductive film, and the second corrugated film 2 can also be a conductive film.

[0027] Along the first direction Z, the first electrode 4 is arranged on the side of the first corrugated film 1 away from the spacing structure 3, and the second electrode 5 is arranged on the side of the second corrugated film 2 away from the spacing structure 3. Specifically, as shown in the figure, Figure 1As shown, the first corrugated film 1 includes a plurality of first peak portions 11 and first valley portions 12 arranged alternately, the second corrugated film 2 includes a plurality of second valley portions 21 and second peak portions 22 arranged alternately, the second valley portion 21 is opposite to the first peak portion 11 in the first direction Z, the second peak portion 22 is opposite to the first valley portion 12 in the first direction Z, along the first direction Z, the spacer structure 3 is arranged between the second peak portion 22 and the first valley portion 12, the first peak portion 11 and the second valley portion 21 form a cavity 7, the cavity 7 is used to accommodate a counter electrode (not labeled in the figure), the first electrode 4 is attached to the side of the first peak portion 11 away from the second valley portion 21, so that the first peak portion 11 and the counter electrode form a first capacitor, the second electrode 5 is attached to the side of the second valley portion 21 away from the first peak portion 11, so that the second valley portion 21 and the counter electrode form a second capacitor, when the micro-electro-mechanical system is working, under the action of the force applied on the first electrode 4 and the first corrugated film 1, the first electrode 4 and the first peak portion 11 can be displaced relative to the counter electrode, so as to change the distance between the first peak portion 11 and the counter electrode in the first direction Z, causing the first capacitor to change and output an electric signal accordingly, under the action of the force applied on the second electrode 5 and the second corrugated film 2, the second electrode 5 and the second valley portion 21 can be displaced relative to the counter electrode, so as to change the distance between the second valley portion 21 and the counter electrode in the first direction Z, causing the second capacitor to change and output an electric signal accordingly, so as to realize the conversion between the acoustic signal and the electric signal.

[0028] The first corrugated film 1 can be made of a conductive material, or the first corrugated film 1 includes an insulating film on which a conductive element is arranged.

[0029] The second corrugated film 2 can be made of a conductive material, or the second corrugated film 2 includes an insulating film on which a conductive element is arranged.

[0030] In the embodiment, a compression layer 6 is arranged between the first electrode 4 and the first corrugated film 1 in the first direction Z, the compression layer 6 has a compression stress, and the first electrode 4 and the first corrugated film 1 have a tensile stress, the first corrugated film 1 increases the flexibility of the overall structure of the first electrode 4, the compression layer 6 and the first corrugated film 1, thereby improving the flexibility of the overall structure of the micro-electro-mechanical system, and further improving the performance of the micro-electro-mechanical system.

[0031] The compression layer 6 can be arranged only between the first electrode 4 and the first corrugated film 1, or only between the second electrode 5 and the second corrugated film 2, or arranged between the first electrode 4 and the first corrugated film 1 and between the second electrode 5 and the second corrugated film 2.

[0032] The compressive stress of the material of the compression layer 6 is greater than or equal to 30 MPa. For example, the compressive stress of the compression layer 6 can be 30 MPa, 35 MPa, 40 MPa, 45 MPa, 50 MPa, 55 MPa, 60 MPa, 65 MPa, 70 MPa, 75 MPa, 80 MPa, 85 MPa, 90 MPa, 95 MPa, 100 MPa, 105 MPa, 110 MPa, and the like.

[0033] Taking the compression layer 6 between the first electrode 4 and the first peak 11 as an example, if the compressive stress of the compression layer 6 is less than 30 MPa, although the flexibility of the overall structure of the micro-electro-mechanical system is improved, the micro-electro-mechanical system is too sensitive, and there is a risk that the micro-electro-mechanical system will convert external small noise into an electrical signal, which will lead to a decline in the performance of the micro-electro-mechanical system.

[0034] Specifically, the material of the compression layer 6 can be silicon dioxide.

[0035] In any of the above embodiments, as shown in Figure 1 The micro-electro-mechanical system further includes a protective wall 8 covering the exposed surface of the compression layer 6. The protective wall 8 can protect the compression layer 6 during processing and reduce the risk of the compression layer 6 being corroded and removed during processing. The protective wall 8 can be retained or removed during subsequent processing.

[0036] Specifically, the material of the protective wall 8 is silicon nitride or polysilicon.

[0037] In one embodiment, as shown in Figure 1 The protective wall 8 is a separately processed structure, i.e., the protective wall 8 and the first electrode 4, the protective wall 8 and the first corrugated film 1, the protective wall 8 and the second electrode 5, and the protective wall 8 and the second corrugated film 2 are separately processed and are in a split structure.

[0038] In another embodiment, as shown in Figure 2 A portion of the first electrode 4 extends in the first direction Z towards the first corrugated film 1 to form the protective wall 8 wrapping the compression layer 6, and a portion of the second electrode 5 extends in the first direction Z towards the second corrugated film 2 to form the protective wall 8 wrapping the compression layer 6. That is, a portion of the protective wall 8 is integrally processed with the first electrode 4, and another portion of the protective wall 8 is integrally processed with the second electrode 5.

[0039] In another embodiment, as shown in Figure 3As shown, a part of the first corrugated film 1 extends towards the first electrode 4 along the first direction Z to form a protection wall 8 wrapping the compression layer 6, and a part of the second corrugated film 2 extends towards the second electrode 5 along the first direction Z to form a protection wall 8 wrapping the compression layer 6. That is, one part of the protection wall 8 is integrally processed with the first corrugated film 1, and the other part of the protection wall 8 is integrally processed with the second corrugated film 2.

[0040] In any of the above embodiments, as shown in Figure 1 The spacing structure 3 includes support walls 31, both ends of the support walls 31 are connected with the first valley part 12 and the second peak part 22 respectively along the first direction Z, and at least two support walls 31 are arranged at intervals between the first valley part 12 and the second peak part 22 along the second direction X; spaces 32 are formed between adjacent support walls 31 along the second direction X.

[0041] By supporting and fixing the first corrugated film 1 and the second corrugated film 2 through the support walls 31 arranged at intervals, the accuracy of the relative position of the first corrugated film 1 and the second corrugated film 2 can be improved, and the material cost and processing cost of the spacing structure 3 can be reduced. At the same time, by sealing and blocking the adjacent chambers 7 through the support walls 31 along the second direction X, the risk of mutual interference of the adjacent electrodes is also reduced, thereby facilitating the improvement of the working stability of the micro-electro-mechanical system. In addition, the first corrugated film 1 and the second corrugated film 2 are connected together through the support walls 31 arranged at intervals, so that the first corrugated film 1 and the second corrugated film 2 do not need to be additionally provided with connecting columns to strengthen the first corrugated film 1 and the second corrugated film 2, thereby making the distance between the first corrugated film 1 and the second corrugated film 2 along the first direction Z closer, and further reducing the inertial second moment.

[0042] The support walls 31 can be integrally formed with the first corrugated film 1 and / or the second corrugated film 2, for example, the support walls 31 are formed between the first corrugated film 1 and the second corrugated film 2 after the first corrugated film 1 and the second corrugated film 2 are assembled together, so as to simplify the connection mode between the support walls 31 and the first corrugated film 1 and the second corrugated film 2, and reduce the installation difficulty of the support walls 31.

[0043] In a possible design, as shown in Figure 1 The space 32 between the adjacent support walls 31 is a cavity, that is, there is no filling substance in the space 32, thereby facilitating the reduction of the overall weight of the micro-electro-mechanical system, so as to facilitate the installation of the micro-electro-mechanical system.

[0044] In another possible design, as shown in Figure 4 The spacing structure 3 further includes a filler 33, and the filler 33 is used to fill the space 32.

[0045] The support wall 31 is made of nitride, the filler 33 filled in the space 32 between the adjacent support walls 31 is made of oxide, and the dielectric constant of the oxide making the filler 33 is less than the dielectric constant of the nitride making the support wall 31, for example, the filler 33 is made of silicon oxide, so that the redundant capacitance between the first corrugated membrane 1 and the second corrugated membrane 2 is significantly reduced, and the change of the capacitance value of the redundant capacitance interferes with the change of the capacitance value of the first capacitance and the second capacitance, so as to further improve the accuracy and precision of the conversion between the acoustic signal and the electric signal of the micro-electro-mechanical system.

[0046] The second aspect of the embodiments of the present application provides a micro-electro-mechanical system, which is the micro-electro-mechanical system in any of the above embodiments.

[0047] When the micro-electro-mechanical system works, the acoustic signal from the outside is transmitted to the micro-electro-mechanical system inside the micro-electro-mechanical system, the acoustic signal causes the first electrode 4 and the first corrugated membrane 1 to move relative to the counter electrode, and the second electrode 5 and the second corrugated membrane 2 to move relative to the counter electrode, so that the first capacitance and the second capacitance change, thereby realizing the conversion between the acoustic signal and the electric signal.

[0048] Since the compression layer 6 is arranged between the first electrode 4 and the first corrugated membrane 1, and / or the compression layer 6 is arranged between the second electrode 5 and the second corrugated membrane 2, the acoustic compliance of the micro-electro-mechanical system is improved, and the sensitivity of the micro-electro-mechanical system is improved.

[0049] The micro-electro-mechanical system can be a microphone or a loudspeaker.

[0050] The above is only the implementation of the present application, and it should be pointed out that those skilled in the art can make improvements without departing from the concept of the present application, but these all belong to the protection scope of the present application.

Claims

1. A microelectromechanical system, characterized in that, The microelectromechanical system includes: The first and second corrugated membranes are positioned directly opposite each other along the first direction; A spacer structure is disposed between the first corrugated membrane and the second corrugated membrane along the first direction; A first electrode, along the first direction, is disposed on the side of the first corrugated membrane opposite to the spacer structure; The second electrode, along the first direction, is disposed on the side of the second corrugated membrane opposite to the spacer structure; A compression layer, along the first direction, is disposed between the first electrode and the first corrugated membrane, and / or, the compression layer is disposed between the second electrode and the second corrugated membrane, the compression layer having compressive stress.

2. The microelectromechanical system according to claim 1, characterized in that, The first corrugated membrane is a non-conductive membrane, and the second corrugated membrane is a non-conductive membrane; Alternatively, the first corrugated membrane may be a conductive membrane, and the second corrugated membrane may be a conductive membrane.

3. The microelectromechanical system according to claim 2, characterized in that, The compressive stress of the material in the compression layer is greater than or equal to 30 MPa.

4. The microelectromechanical system according to claim 3, characterized in that, The material of the compression layer is silicon dioxide.

5. The microelectromechanical system according to claim 2, characterized in that, The microelectromechanical system also includes a protective wall that covers the exposed surface of the compression layer.

6. The microelectromechanical system according to claim 5, characterized in that, The protective wall is made of silicon nitride or polycrystalline silicon.

7. The microelectromechanical system according to claim 5, characterized in that, A portion of the first electrode extends toward the first corrugated membrane along the first direction, and a portion of the second electrode extends toward the second corrugated membrane along the first direction to form the protective wall; Alternatively, a portion of the first corrugated membrane extends toward the first electrode along the first direction, and a portion of the second corrugated membrane extends toward the second electrode along the first direction to form the protective wall.

8. The microelectromechanical system according to any one of claims 1 to 7, characterized in that, The first corrugated membrane includes a plurality of alternating first peaks and first valleys, and the second corrugated membrane includes a plurality of alternating second valleys and second peaks, wherein the second valleys and the first peaks are directly opposite each other in the first direction, and the second peaks and the first valleys are directly opposite each other in the first direction. Along the first direction, the spacing structure is disposed between the second peak and the first valley, the first electrode is located on the side of the first peak away from the second valley, and the second electrode is located on the side of the second valley away from the first peak.

9. The microelectromechanical system according to claim 8, characterized in that, The spacing structure includes a support wall. Along the first direction, the two ends of the support wall are respectively connected to the first valley and the second peak. Along the second direction, at least two support walls are spaced apart between the first valley and the second peak. Along the second direction, a space is formed between adjacent supporting walls; The spacer structure also includes filler material for filling the space.

10. An electromechanical conversion device, characterized in that, The electromechanical conversion device includes a microelectromechanical system (MEMS), which includes: The first and second corrugated membranes are positioned directly opposite each other along the first direction; A spacer structure is disposed between the first corrugated membrane and the second corrugated membrane along the first direction; A first electrode, along the first direction, is disposed on the side of the first corrugated membrane opposite to the spacer structure; The second electrode, along the first direction, is disposed on the side of the second corrugated membrane opposite to the spacer structure; A compression layer, along the first direction, is disposed between the first electrode and the first corrugated membrane, and / or, the compression layer is disposed between the second electrode and the second corrugated membrane, the compression layer having compressive stress.

Images