A micro-electromechanical system and an electroacoustic conversion device having the same

Abstract

The present application discloses a micro-electromechanical system (MEMS) and an electroacoustic converter having the MEMS. The MEMS includes: a first diaphragm; a second diaphragm disposed opposite the first diaphragm; a plurality of support members, the support members including a plurality of support walls, the opposite ends of the support walls respectively connecting the first diaphragm and the second diaphragm, the first diaphragm, the second diaphragm, and two adjacent support walls in the same support member forming a first chamber; a connecting groove disposed on the first diaphragm or on both the first diaphragm and the second diaphragm, for connecting the first chamber to the outside. By providing a support body consisting of a plurality of support walls and providing a connecting groove on the first diaphragm or on both the first diaphragm and the second diaphragm, the flexibility of the first diaphragm or the second diaphragm is increased, while the inter-plate capacitance between the first diaphragm and the second diaphragm is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of electroacoustic conversion devices, and in particular to a micro-electromechanical system and an electroacoustic conversion device having the micro-electromechanical system. Background Art

[0002] In an existing MEMS with a double-membrane structure, it includes an upper membrane, a lower membrane, and several supports for connecting the upper membrane and the lower membrane. The supports allow the upper membrane and the lower membrane to be connected at the place where they are closest.

[0003] In some designs, the mechanical compliance of the dual-membrane structure needs to be adjusted. When the dual-membrane structure is subjected to pressure, it deforms, resulting in bending strain in the cross-section of the support. The stiffer this region is when bending, the less compliant the entire dual-membrane structure becomes. The greater the bending compliance of this region, the more compliant the entire dual-membrane structure becomes, and the higher the microphone sensitivity.

[0004] The present application relates to a support member and changing its compliance, primarily to increasing its compliance so that a double membrane structure can have higher compliance without changing other design or material parameters. Summary of the Invention

[0005] In view of the above problems, the present application provides a micro-electromechanical system and an electroacoustic conversion device having the micro-electromechanical system to solve the technical problems in the prior art, which can improve the flexibility of the double-membrane structure.

[0006] In a first aspect, the present application provides a micro-electromechanical system, comprising:

[0007] First diaphragm;

[0008] a second diaphragm, disposed opposite to the first diaphragm;

[0009] a plurality of support members disposed between the first diaphragm and the second diaphragm, the support members comprising a plurality of support walls, opposite ends of the support walls being connected to the first diaphragm and the second diaphragm, respectively, and the first diaphragm, the second diaphragm, and two adjacent support walls in the same support member enclosing a first chamber;

[0010] The communication groove is provided on the first diaphragm or on both the first diaphragm and the second diaphragm, and is used to connect the first chamber with the outside.

[0011] In the technical solution of the embodiment of the present application, a support body composed of a plurality of support walls is provided and a connecting groove is provided on the first diaphragm or on both the first diaphragm and the second diaphragm, thereby increasing the flexibility of the first diaphragm or the second diaphragm and reducing the inter-plate capacitance between the first diaphragm and the second diaphragm.

[0012] In some embodiments, the connecting groove includes a slit-shaped groove structure, a circular groove structure, a waist-shaped groove structure, an angular groove structure or an S-shaped groove structure.

[0013] In some embodiments, each of the supporting members is provided with a plurality of the communicating grooves, and the plurality of communicating grooves are spaced apart along the first direction.

[0014] In some embodiments, the communicating groove runs through the first diaphragm, and a partial area within the first chamber is filled with a filling material.

[0015] In some embodiments, the support member includes multiple first chambers. In two adjacent first chambers, the connecting groove of one of the first chambers is opened on the first diaphragm, and the connecting groove of the other first chamber is opened on the second diaphragm.

[0016] In some embodiments, the first diaphragm includes a plurality of first peaks and first grooves alternately arranged in the second direction, and the second diaphragm includes a plurality of second peaks and second grooves alternately arranged in the second direction, the first peaks are opposite to the second grooves, and the first grooves are opposite to the second peaks, and the opposite first peaks and second grooves are surrounded by two adjacent supporting walls to form a second chamber, and a counter electrode is provided in the second chamber.

[0017] In some embodiments, the support member is sandwiched between opposing first troughs and second peaks.

[0018] In some embodiments, the filler material is silicon oxide.

[0019] In some embodiments, the support wall is made of polysilicon or silicon nitride.

[0020] In a second aspect, the present application further provides an electroacoustic conversion device, comprising the aforementioned micro-electromechanical system and a circuit device electrically connected to the micro-electromechanical system.

[0021] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0023] Figure 1 It is a structural schematic diagram of the first connecting groove structure;

[0024] Figure 2 1 is a schematic structural diagram of the first connecting groove structure when filled with filling material;

[0025] Figure 3 It is a structural schematic diagram of the first connecting groove structure under the counter electrode condition;

[0026] Figure 4 1 is a structural diagram of the second connecting groove structure;

[0027] Figure 5 1 is a structural diagram of the third connecting groove structure;

[0028] Figure 6 1 is a structural diagram of the fourth connecting groove structure;

[0029] Figure 7 1 is a structural diagram of the fifth connecting groove structure;

[0030] Figure 8 1 is a structural diagram of the sixth connecting groove structure;

[0031] Figure 9 1 is a structural diagram of the seventh connecting groove structure;

[0032] Figure 10 It is a structural diagram of the first support structure;

[0033] Figure 11 1 is a structural diagram of the second support structure;

[0034] Figure 12 is a top view of the first diaphragm;

[0035] Figure 13 It is a structural diagram of an electroacoustic conversion device.

[0036] In the accompanying drawings, the drawings are not necessarily drawn to scale.

[0037] The accompanying drawings in the specific implementation manner are as follows:

[0038] 10-first membrane, 11-first peak, 12-first trough;

[0039] 20-second membrane, 21-second peak, 22-second trough;

[0040] 30-support member, 31-support wall, 32-first chamber, 33-second chamber;

[0041] 40- communication groove;

[0042] 50-filling material;

[0043] 60-counter electrode, 61-conductive element;

[0044] 70-spokes;

[0045] 100-Electroacoustic conversion device;

[0046] 200-Micro-Electro-Mechanical Systems;

[0047] 300-Circuit Device. DETAILED DESCRIPTION

[0048] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and are not to be construed as limiting the present invention.

[0049] Reference Figure 1 As shown, the present application provides a micro-electromechanical system 200, including a first diaphragm 10, a second diaphragm 20, a support member 30 and a connecting groove 40:

[0050] The first diaphragm 10 and the second diaphragm 20 are arranged opposite to each other, and the first diaphragm 10 is located above the second diaphragm 20. In this embodiment, the first diaphragm 10 and the second diaphragm 20 are both concentrically arranged circular structures, and the circumferential direction of the circular structure is set as the first direction, and the radial direction of the circular structure is set as the second direction.

[0051] A cavity is formed between the first diaphragm 10 and the second diaphragm 20, and the support member 30 and the counter electrode 60 mentioned later are both located in this cavity. The first diaphragm 10 and the second diaphragm 20 can be made of conductive materials, or include insulating films with conductive elements arranged thereon.

[0052] The support member 30 is arranged in the cavity between the first diaphragm 10 and the second diaphragm 20. There can be multiple support members 30, and the multiple support members 30 are arranged at intervals along the second direction. The support member 30 includes a plurality of support walls 31. The support walls 31 extend along the first direction. The opposite ends of the support walls 31 are respectively connected to the first diaphragm 10 and the second diaphragm 20 to mechanically couple the first diaphragm 10 and the second diaphragm 20. The support walls 31 are preferably made of silicon nitride.

[0053] The first diaphragm 10, the second diaphragm 20 and two adjacent support walls 31 in the same support member 30 together form a first chamber 32. The first chamber 32 may be filled with a filling material 50, which may be an oxide such as silicon oxide. Alternatively, the first chamber 32 may be empty.

[0054] The communication groove 40 extends through the first diaphragm 10 and / or the second diaphragm 20 corresponding to the support member 30 and is used to connect the first chamber 32 to the outside. The communication groove 40 can be provided only on the first diaphragm 10 or on both the first diaphragm 10 and the second diaphragm 20. By providing the communication groove 40, air or etching solution from the external environment is allowed to enter the first chamber 32 to release the filling material 50, thereby increasing the flexibility of the first diaphragm 10 or the second diaphragm 20 and reducing the inter-plate capacitance between the first diaphragm 10 and the second diaphragm 20.

[0055] Continue to refer to Figure 1 As shown, Figure 1 This is a schematic diagram of the first type of connecting groove structure. This figure shows a case where only the connecting groove 40 is provided on the first diaphragm 10, with no connecting groove 40 provided on the second diaphragm 20. The amount of increased compliance of the first diaphragm 10 depends on the size and shape of the connecting groove 40. The larger the connecting groove 40, the greater the increased compliance of the first diaphragm 10. After the filler material 50 is released, the width of the support members 30 is allowed to expand, thereby reducing the distance between two adjacent support members 30 in the second direction, eliminating inherent stress in the first diaphragm 10 and increasing the compliance of the entire dual-diaphragm structure.

[0056] Reference Figure 4 As shown, Figure 4 This is a schematic diagram of the structure of the second connecting groove structure. This figure shows the situation where the connecting groove 40 is set on the first diaphragm 10 and the second diaphragm 20 at the same time. The relatively arranged connecting grooves 40 completely release the filling material 50 filled in the first chamber 32. This is equivalent to creating a vent that runs through the first diaphragm 10 and the second diaphragm 20, thereby significantly increasing the flexibility of the membrane in the area where the connecting groove 40 is located to bending. The connecting grooves 40 on the first diaphragm 10 and the second diaphragm 20 can have the same size and shape, or they can be different, which is not limited here. In some embodiments, the connecting groove 40 on the first diaphragm 10 is very large, almost reaching the edge of the support wall 31, while the connecting groove 40 on the second diaphragm 20 is much smaller. In some embodiments, the connecting groove 40 on the second diaphragm 20 is very large, while the connecting groove 40 on the first diaphragm 10 is smaller.

[0057] Refer to Figures 5 to 9As shown, in some embodiments, the connecting groove 40 includes a slit-shaped groove structure, a circular groove structure, a waist-shaped groove structure, an angular groove structure, or an S-shaped groove structure. The connecting groove 40 can be made large enough to allow sufficient release of the filling material 50 while improving compliance. The size and shape of the connecting groove 40 are selected to strike a balance between increasing the compliance of the support member 30 and reducing the mechanical stress on the first diaphragm 10 or the second diaphragm 20. Those skilled in the art will appreciate that the structure of the connecting groove 40 can be modified in many different ways, and can be a regular or irregular pattern, which is not limited here.

[0058] Reference Figure 5 As shown, Figure 5 3 is a schematic structural diagram of a third communicating groove structure. The communicating groove 40 is a slit-shaped groove body structure. The slit-shaped groove body structure penetrates the first diaphragm 10 corresponding to the support member 30 and extends along the first direction.

[0059] In one embodiment, each support member 30 may correspond to a plurality of slit-shaped slot structures, and the plurality of slit-shaped slots are spaced apart along the first direction. The first diaphragm 10 remains partially connected in the region corresponding to the support member 30 .

[0060] In another embodiment, each support member 30 corresponds to only one slit-shaped slot structure. Figure 5 As shown, the slit-shaped groove structure passes through the first diaphragm 10 and extends along the circumference of the first diaphragm 10, completely breaking the mechanical connection between the support member 30 and the corresponding area of the first diaphragm 10, thereby achieving the highest flexibility.

[0061] Reference Figures 6 to 9 As shown, Figure 6 1 is a structural diagram of the fourth connecting groove structure; Figure 7 1 is a structural diagram of the fifth connecting groove structure; Figure 8 1 is a structural diagram of the sixth connecting groove structure; Figure 9 This is a schematic diagram of the seventh connecting groove structure. The connecting grooves 40 of the above four structures extend through the first diaphragm 10. Each support member 30 is provided with multiple connecting grooves 40. The connecting grooves 40 are spaced apart along the first direction. Preferably, the connecting grooves 40 are evenly spaced. This further improves the compliance of the first diaphragm 10, and the degree of improvement depends on the number and size of the connecting grooves 40.

[0062] Reference Figure 2 As shown, Figure 2It is a structural schematic diagram of the first connecting groove structure when filled with filling material; the connecting groove 40 runs through the first diaphragm 10, and a partial area in the first chamber 32 has a filling material 50, which is close to the second diaphragm 20. The size of the connecting groove 40 is small, and the filling material 50 in the first chamber 32 is only partially released, which can increase the flexibility of the first diaphragm 10 on the one hand, and limit the stress concentration on the interface between the second diaphragm 20 or the support wall 31 and the second diaphragm 20 on the other hand.

[0063] The support wall 31 is preferably made of silicon nitride, and the filling material 50 partially filled in the first cavity 32 is preferably silicon oxide having a dielectric constant smaller than that of silicon nitride, so that the inter-plate capacitance between the first diaphragm 10 and the first diaphragm 10 is significantly reduced.

[0064] Preferably, the support member 30 includes a plurality of support walls 31 , thereby forming a plurality of first chambers 32 . In two adjacent first chambers 32 , the communicating groove 40 of one first chamber 32 is opened on the first diaphragm 10 , and the communicating groove 40 of the other first chamber 32 is opened on the second diaphragm 20 .

[0065] like Figure 10 As shown, Figure 10 It is a structural schematic diagram of the first support structure. The connecting grooves 40 located on the first diaphragm 10 and the connecting grooves 40 located on the second diaphragm 20 are alternately arranged. Each connecting groove 40 corresponds to a first chamber 32. The areas of the first diaphragm 10 and the second diaphragm 20 corresponding to the support 30 form a corrugated structure. At the same time, the filling materials 50 in several first chambers 32 are released, thereby further improving the flexibility of the double membrane structure.

[0066] Reference Figure 11 As shown, Figure 11 This is a structural diagram of the second support structure. The corrugated structure formed by the support 30 extends to the entire membrane, so that there is no sealed space between the first diaphragm 10 and the second diaphragm 20, which is more flexible than the traditional membrane formed by the traditional single-layer deposition material.

[0067] Reference Figure 3 and Figure 12 As shown, Figure 3 It is a structural diagram of the first connecting groove structure under the counter electrode condition. Figure 12 FIG2 is a top view of a first diaphragm. The first diaphragm 10 includes a plurality of first peaks 11 and first grooves 12 arranged alternately in a second direction. The second diaphragm 20 includes a plurality of second peaks 21 and second grooves 22 arranged alternately in the second direction. The first peaks 11 are opposite the second grooves 22, and the first grooves 12 are opposite the second peaks 21.

[0068] A second chamber 33 is formed between the first diaphragm 10 and the second diaphragm 20, wherein the second chamber 33 is airtightly sealed. In some embodiments, its internal pressure is less than the external atmosphere, wherein the internal pressure of the second chamber 33 is less than 0.2atm. Preferably, the pressure in the second chamber 33 is equal to 0.1atm. In some embodiments, the second chamber 33 is vacuum.

[0069] Continue to refer to Figure 3 and Figure 12 As shown, a counter electrode 60 is disposed in the second chamber 33 . In some embodiments, the counter electrode 60 is suspended in the second chamber 33 using spokes 70 , and there is no mechanical coupling between the counter electrode 60 and the support member 30 .

[0070] Conductive elements 61 are disposed on opposing upper and lower surfaces of the counter electrode 60, respectively. The first peaks 11 are spaced apart from the conductive elements 61 of the counter electrode 60, forming a first capacitance therebetween. The second grooves 22 are spaced apart from the corresponding conductive elements 61 of the counter electrode 60, forming a second capacitance therebetween. In response to pressure applied to the first peaks 11 and second grooves 22, the first peaks 11 and second grooves 22 are movable relative to the corresponding counter electrode 60, thereby changing the distance between the first peaks 11 and second grooves 22 and the corresponding counter electrode 60 of the support member 30. This causes the capacitance to change and a corresponding electrical signal to be output.

[0071] Alternatively, the counter electrode 60 includes a single conductor, so that a first capacitor is formed between the first diaphragm 10 and the single conductor, and a second capacitor is formed between the second diaphragm 20 and the single conductor.

[0072] Continue to refer to Figure 3 As shown, a plurality of support walls 31 are respectively sandwiched between the opposing first grooves 12 and second peaks 21, and the first grooves 12 and second peaks 21 are connected together by corresponding support walls 31 of the support member 30. The support walls 31 can be integrally formed with one of the first diaphragm 10 and the second diaphragm 20. Alternatively, the support walls 31 are formed between the first grooves 12 and the second peaks 21 after the first diaphragm 10 and the second diaphragm 20 are assembled together.

[0073] The present invention also provides an electroacoustic conversion device 100, referring to Figure 13 As shown, the electroacoustic conversion device 100 includes the aforementioned micro-electromechanical system 200 and a circuit device 300 (ASIC) electrically connected to the micro-electromechanical system 200 . The electroacoustic conversion device 100 may be a microphone or a speaker.

[0074] The above describes in detail the structure, features and effects of the present invention based on the embodiments shown in the drawings. The above is only a preferred embodiment of the present invention, but the present invention is not limited to the scope of implementation shown in the drawings. Any changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which do not exceed the spirit covered by the description and drawings, should be within the scope of protection of the present invention.

Claims

1. A micro-electromechanical system, characterized in that: include: First diaphragm; a second diaphragm, disposed opposite to the first diaphragm; a plurality of support members disposed between the first diaphragm and the second diaphragm, the support members comprising a plurality of support walls, opposite ends of the support walls being connected to the first diaphragm and the second diaphragm, respectively, and the first diaphragm, the second diaphragm, and two adjacent support walls in the same support member enclosing a first chamber; an opening, provided on the first diaphragm or provided on both the first diaphragm and the second diaphragm, for connecting the first chamber with the outside; The support member includes a plurality of first chambers. In two adjacent first chambers, the opening of one of the first chambers is opened on the first diaphragm, and the opening of the other first chamber is opened on the second diaphragm.

2. The micro-electromechanical system according to claim 1, wherein: The opening includes a slit-shaped hole structure, a circular hole structure, a waist-shaped hole structure, an angular hole structure or an S-shaped hole structure.

3. The micro-electromechanical system according to claim 1, wherein: Each of the supporting members is correspondingly provided with a plurality of the openings, and the plurality of the openings are spaced apart along the first direction.

4. The micro-electromechanical system according to claim 1, wherein: The opening penetrates the first diaphragm, and a partial area within the first cavity is filled with a filling material.

5. The micro-electromechanical system according to claim 1, wherein: The first diaphragm includes a plurality of first peaks and first grooves alternately arranged in the second direction, and the second diaphragm includes a plurality of second grooves and second peaks alternately arranged in the second direction, the first peaks are opposite to the second peaks, and the first grooves are opposite to the second grooves, and the opposite first peaks and second peaks are surrounded by the two adjacent support walls to form a second chamber, and a counter electrode is arranged in the second chamber.

6. The micro-electromechanical system according to claim 5, wherein: The support member is sandwiched between the first and second opposing grooves.

7. The micro-electromechanical system according to claim 4, wherein: The filling material is silicon oxide.

8. The micro-electromechanical system according to claim 1, wherein: The support wall is made of polysilicon or silicon nitride.

9. An electroacoustic conversion device, comprising the micro-electromechanical system according to any one of claims 1 to 8 and a circuit device electrically connected to the micro-electromechanical system.

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