Micro-electromechanical structures and methods for regulating their mechanical properties

Abstract

The present invention provides a method for regulating a micro-electromechanical structure and its mechanical properties, the regulating method comprising: applying electricity to an electrode to drive a mass block to move in a vertical first direction, wherein the first direction is the structural functional direction of the micro-electromechanical structure; when the displacement of the mass block in the vertical first direction increases to trigger the locking of two parts of a locking assembly, so that a part of the locking assembly on the mass block is locked with another part of the locking assembly on the movement path of the mass block in the vertical first direction, the mass block stops moving in the vertical first direction after being connected and fixed to the other part of the locking assembly on the movement path in the vertical first direction, and the mechanical properties of the micro-electromechanical structure in the first direction are changed. In the above manner, under the drive of an externally applied second electrode, the total stiffness of the cantilever beam supported by the mass block when it moves in the first direction can be irreversibly changed to form a micro-electromechanical structure with different properties.

Description

Technical Field

[0001] The present invention relates to the technical field of micro-electromechanical systems, and in particular to a micro-electromechanical structure and a method for regulating and controlling its mechanical properties. Background Art

[0002] Micro-electromechanical systems (MEMS) are developed on the basis of microelectronics technology. They are micro devices or systems that integrate micro sensors, micro actuators, micro mechanical structures, micro power sources, signal processing and control circuits, high-performance electronic integrated devices, interfaces, and communications. MEMS is a revolutionary new technology that is widely used in high-tech industries.

[0003] Common products include MEMS accelerometers, MEMS microphones, micromotors, micropumps, microvibrators, MEMS optical sensors, MEMS pressure sensors, MEMS gyroscopes, MEMS humidity sensors, MEMS gas sensors, etc. and their integrated products.

[0004] The sensitive structure chips of MEMS products are usually manufactured in a similar way to integrated circuits, through micro-machining processes such as lithography, corrosion, thin film deposition, ion implantation, epitaxy, and wafer bonding on wafers. The scale effect generated by increasing the wafer size improves the consistency of processing and reduces the cost of a single chip.

[0005] The wafer diameter of the current mainstream MEMS production line in the industry is 6 to 8 inches, and each wafer contains hundreds to tens of thousands of MEMS chips. For some high-end MEMS products, the price is high but the market demand is small, and it is often necessary to define separate product models for special application environments. There are many subdivisions, and the shipment volume of each subdivision model is not large. If each subdivision model is taped out separately, it will cause great obstacles to production and operation management.

[0006] In view of the above problems, for products with many sub-categories and low demand, the existing technology usually adopts the multi-target wafer (MPW) method for processing, that is, processing multiple MEMS chips with different designs but similar processing technology on the same wafer at the same time. This method significantly reduces the number of chips of a single design on each wafer, but due to the inevitable differences in key dimensions of structures with different design performances, when processing chips of multiple designs on the same wafer, it is impossible to optimize the processing technology to perfectly match the requirements of each design. The chips on the wafers processed by this method are usually difficult to ensure consistency, and the yield is low, which significantly increases the cost of testing calibration and screening effective chips.

[0007] In view of this, there is an urgent need to provide a new method for regulating MEMS structures and their mechanical properties to solve the above defects. Summary of the invention

[0008] Based on this, the present invention provides a method for regulating a micro-electromechanical structure and its mechanical properties, which changes the mechanical structure of the micro-electromechanical structure by cooperating with an external excitation signal and a locking component, and transforms structural chips of the same design into different mechanical properties, so as to solve the problem in the prior art that different processing designs need to be used to form different MEMS structural chips on the same wafer.

[0009] The present invention provides a method for regulating the mechanical properties of a micro-electromechanical structure, comprising:

[0010] Powering up the electrodes to drive the mass block to move in a vertical first direction, wherein the first direction is a structural functional direction of the micro-electromechanical structure;

[0011] When the displacement of the mass block in the first direction perpendicular to the vertical direction increases to trigger the locking of the two parts of the locking assembly, so that the partial locking assembly on the mass block is locked with the other partial locking assembly on the movement path of the mass block in the first direction perpendicular to the vertical direction, the mass block stops moving in the first direction perpendicular to the vertical direction after being connected and fixed to the other partial locking assembly on the movement path in the first direction, and the mechanical properties of the micro-electromechanical structure in the first direction change.

[0012] Preferably, the locking assembly includes a lock buckle provided on the mass block and a lock groove locked with the lock buckle.

[0013] Preferably, the lock buckle comprises a connecting rod extending from the mass block toward the lock slot and a lock head provided at one end of the connecting rod away from the mass block, wherein the lock head is a triangle with its head facing the lock slot.

[0014] The lock slot includes an anchor block fixed on the substrate, two connecting arms extending from the anchor block toward the lock buckle, and a lock hook from the connecting arm away from the anchor block. The two lock hooks extend toward the opposite side, and the two lock hooks, the two connecting arms and the anchor block surround a receiving cavity for receiving the lock head.

[0015] The present invention also provides a micro-electromechanical structure, comprising:

[0016] substrate;

[0017] A mass block is disposed on the substrate;

[0018] A cantilever beam, at least two of which are disposed around the mass block, one end of which is fixedly connected to the substrate and the other end of which is connected to the mass block, so as to suspend the mass block on the substrate;

[0019] A first electrode, connected to the mass block via a capacitor, driving the mass block to reciprocate in a first direction or detecting the movement acceleration of the mass block in the first direction;

[0020] A second electrode, connected to the mass block via a capacitor, driving the mass block to move in a vertical first direction;

[0021] A locking assembly, part of which is disposed on the mass block, and the other part of which is disposed on the substrate and is arranged opposite to the part disposed on the mass block, wherein the two parts of the locking assembly are disposed on a path of the mass block moving in a vertical first direction;

[0022] An electrical signal is applied to the second electrode to drive the mass block to displace in a direction perpendicular to the first direction. When the displacement increases to trigger the locking of the two parts of the locking assembly, the mass block is fixed to change the position of the mass block in the first direction and thus change the structure of the micro-electromechanical structure.

[0023] Preferably, the locking assembly comprises a lock buckle provided on the mass block and a lock groove provided on the substrate and engaged with the lock buckle;

[0024] When the mass block moves in a vertical first direction, the lock buckle is driven to move into the locking slot, and the locking slot locks the lock buckle to fix the mass block at the position where the locking slot is located on the substrate.

[0025] Preferably, the lock buckle comprises a connecting rod extending from the mass block toward the lock slot and a lock head provided at one end of the connecting rod away from the mass block, wherein the lock head is a triangle with its head facing the lock slot.

[0026] The lock slot includes an anchor block fixed on the substrate, two connecting arms extending from the anchor block toward the lock buckle, and a lock hook from the connecting arm away from the anchor block. The two lock hooks extend toward the opposite side, and the two lock hooks, the two connecting arms and the anchor block surround a receiving cavity for receiving the lock head.

[0027] Preferably, at least one of the lock buckle and the lock groove can undergo elastic deformation in the first direction.

[0028] Preferably, the mass block is square, and the four cantilever beams are connected to four vertices of the mass block in a one-to-one correspondence.

[0029] Preferably, the cantilever beam comprises an anchor point arranged on the substrate and an elastic element connecting the anchor point and the vertex of the mass block, and when stationary, the lengths of the elastic elements of the four cantilever beam arms are the same.

[0030] Preferably, first movable comb teeth are disposed on both sides of the mass block extending along the first direction.

[0031] The first electrode includes a first fixed block fixed on the substrate and a first fixed comb tooth provided on the first fixed block.

[0032] The first fixed comb teeth extend into the gaps of the first movable comb teeth correspondingly;

[0033] and / or, the mass block is provided with second movable comb teeth on both sides extending perpendicular to the first direction,

[0034] The second electrode includes a second fixed block fixed on the substrate and second fixed comb teeth arranged on the second fixed block.

[0035] The second fixed comb teeth extend into the gaps of the second movable comb teeth correspondingly;

[0036] And / or, the second electrode includes two electrodes that are symmetrically arranged.

[0037] The beneficial effect of the present invention is that a method for regulating a micro-electromechanical structure and its mechanical properties is provided, and the regulating method includes: applying electricity to the electrodes to drive the mass block to move in a vertical first direction, wherein the first direction is the structural functional direction of the micro-electromechanical structure; when the displacement of the mass block in the vertical first direction increases to trigger the locking of two parts of the locking assembly, so that a part of the locking assembly on the mass block is locked with another part of the locking assembly on the movement path of the mass block in the vertical first direction, the mass block is connected and fixed to the other part of the locking assembly on the movement path in the vertical first direction and stops moving in the vertical first direction, and the mechanical properties of the micro-electromechanical structure in the first direction are changed. In the above manner, under the drive of the external second electrode, the total stiffness of the cantilever beam supported by the mass block when it moves in the first direction can be irreversibly changed to form micro-electromechanical structures with different properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic structural diagram of a micro-electromechanical structure according to an embodiment of the present invention;

[0039] Figure 2 for Figure 1 A schematic diagram of the structure of the locking component in the micro-electromechanical structure shown;

[0040] Figure 3 A flow chart of a method for regulating the mechanical properties of a micro-electromechanical structure;

[0041] The meanings of the symbols in the accompanying drawings are:

[0042] MEMS structure 100; substrate 1; mass block 2; first movable comb teeth 21; second movable comb teeth 22; cantilever beam 3; anchor point 31; elastic element 32; first electrode 4; first fixed block 41; first fixed comb teeth 42; second electrode 5; second fixed block 51; second fixed comb teeth 52; locking assembly 6; lock buckle 61; connecting rod 611; lock head 612; lock groove 62; anchor block 621; connecting arm 622; lock hook 623. DETAILED DESCRIPTION

[0043] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0044] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element at the same time.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0046] like Figures 1 to 3As shown, it is a schematic diagram of the structure of a micro-electromechanical structure of an embodiment of the present invention. The micro-electromechanical structure 100 includes a substrate 1, a mass block 2 arranged on the substrate 1, four cantilever beams 3 arranged outside the mass block 2, a first electrode 4 connected to the mass block 2 through a capacitor, a second electrode 5 connected to the mass block 2 through a capacitor, and a locking assembly 6 partially arranged on the mass block 2 and another part arranged on the substrate 1. One end of each cantilever arm 3 is fixedly connected to the substrate 1 and the other end is connected to the mass block 2 to suspend the mass block 2 on the substrate 1; when the micro-electromechanical structure 100 is an actuator, the first electrode 4 is used to drive the mass block 2 to reciprocate in the first direction, and when the micro-electromechanical structure 100 is a sensor, the first electrode 4 is used to detect the motion acceleration of the mass block 2; the second electrode 5 drives the mass block 2 to move in a vertical first direction; the two parts of the locking assembly 6 are arranged opposite to each other and are arranged on the path of the mass block 2 moving in the vertical first direction, and are used to fix the mass block 2.

[0047] The mass block 2 in the embodiment of the present invention is a square. Of course, the mass block 2 can also be other shapes such as a rectangle or a circle, and is not limited to the above examples. The four cantilever beams 3 are evenly distributed and enclosed in a square. The mass block 2 is located in the center of the enclosed square, and the diagonal of the square of the mass block 2 overlaps with the diagonal of the square enclosed by the cantilever beams 3. The four cantilever beams 3 are respectively arranged at the four vertices of the enclosed square, one end of which corresponds to the substrate position corresponding to the vertex, and the other end is connected to the square vertex of the mass block 2, so that the angle between the extension direction of the cantilever beam and the first direction is 45°. In the embodiment of the present invention, the first direction is the extension direction of two sides of the mass block 2. Of course, in other embodiments, the number of cantilever beams 3 can be set to other even numbers, and at least two cantilever beams 3 are provided, that is, a pair of cantilever beams 3 are provided. And the direction of the cantilever beam is not limited to the direction in this embodiment. Preferably, the cantilever beam 3 includes an anchor point 31 disposed on the substrate 1 and an elastic element 32 connecting the anchor point 31 and the vertex of the mass block 2. When stationary, the four elastic elements 32 connected to the four vertices of the mass block 2 have the same length. The mass block 2 is connected to the substrate 1 through the cantilever beam 3 inclined at 45°. The cantilever beam 3 has a lower stiffness in both the first direction and the perpendicular first direction, and has a higher stiffness in the third direction outside the plane. Of course, the arrangement of the four cantilever beams 3 and the mass block 2 is not limited to the illustrated structure of the present invention, as long as the cantilever beam 3 can enable the mass block 2 to have degrees of freedom in two directions, namely the degree of freedom in the first direction of the normal structure and the degree of freedom in the perpendicular first direction.

[0048] In an optional embodiment, the mass block 2 is provided with first movable comb teeth 21 on both sides extending along the first direction, the first electrode 4 includes a first fixed block 41 fixed on the substrate 1 and a first fixed comb tooth 42 provided on the first fixed block 41, the first fixed comb tooth 42 correspondingly extends into the gap of the first movable comb tooth 21, so that the first electrode 4 is connected to the mass block 2 through capacitance. Optionally, the mass block 2 is provided with second movable comb teeth 22 on both sides extending along the perpendicular first direction, the second electrode 5 includes a second fixed block 51 fixed on the substrate 1 and a second fixed comb tooth 52 provided on the second fixed block 51, the second fixed comb tooth 52 correspondingly extends into the gap of the second movable comb tooth 22, so that the second electrode 5 is connected to the mass block 2 through capacitance. Optionally, in the embodiment of the present invention, the second electrode 5 includes two symmetrically arranged ones.

[0049] In an optional embodiment, the locking assembly 6 includes a lock buckle 61 provided on the mass block 2 and a lock slot 62 provided on the substrate 1 and engaged with the lock buckle 61. When the mass block moves in a vertical first direction, the lock buckle is driven to move into the lock slot, and the lock slot locks the lock buckle to fix the mass block at the position where the lock slot is located on the substrate.

[0050] Optionally, the lock buckle 61 includes a connecting rod 611 extending from the mass block 2 toward the lock slot 62 and a lock head 612 provided at one end of the connecting rod 611 away from the mass block 2, wherein the lock head 612 is a triangle with its head facing the lock slot 62. The lock slot 62 includes an anchor block 621 fixed on the substrate 1, two connecting arms 622 extending from the anchor block 621 toward the lock buckle 61, and a lock hook 623 from one side of the connecting arm 622 away from the anchor block 621, wherein the two lock hooks 623 extend toward one side opposite to the other, and the two lock hooks 623, the two connecting arms 622, and the anchor block 621 surround a receiving cavity for receiving the lock head 612. When the second electrode 5 applies an external driving signal to the mass block 2, a force is applied to the mass block 2 to move in the vertical first direction. Under the action of the force, the lock buckle 61 on the mass block 2 moves toward the lock groove 62 on the substrate 1. If the applied force is large enough, the mass block 2 generates a large enough displacement in the vertical first direction, so that the lock head 612 of the lock buckle 61 moves into the accommodating cavity of the lock groove 62 under the action of acceleration, and the lock head 612 abuts against the lock hook 623 near one end of the connecting rod 611, so that the lock buckle 61 cannot return to the original position, and the locking assembly 6 locks the mass block 2, thereby changing the position of the mass block 2 in the vertical first direction to change the internal structure and design of the micro-electromechanical structure 100. Optionally, at least one of the lock buckle 61 and the lock groove 62 has elastic deformation in the first direction, so that the locking assembly 6 can maintain elasticity in the first direction.

[0051] The micro-electromechanical structure 100 of the embodiment of the present invention, the material of the substrate 1 is generally made of silicon, and the working principle is to apply a driving signal to the first electrode 4 through the interface circuit, so that the mass block 2 vibrates in the first direction at the modal frequency of the structure in the first direction, and its natural frequency is jointly determined by the mass of the mass block 2 and the stiffness of the cantilever beam 3 connected to the mass block 2 in the first direction. When it is detected that the mass block 2 has an external acceleration in the first direction, the mass block 2 is displaced, driving the cantilever beam 3 to generate stress, so that the stiffness of the cantilever beam 3 in the first direction of movement changes, thereby causing the modal frequency of the structure in the first direction to change, and the internal vibration loop of the interface circuit detects the change in vibration frequency and converts it into an output signal that can characterize the external input acceleration.

[0052] If a driving signal is applied through the second electrode 5 to cause the mass block 2 to generate a sufficiently large displacement in the vertical first direction, so that the locking assembly 6 on the right side meets the locking relative position, so that the two parts of the locking assembly 6 cooperate to lock, then the locking assembly 6 is equivalent to the cantilever beam 3 additionally connected to the mass block 2, and the stiffness of the locking assembly 6 in the vertical first direction will be additionally superimposed into the original resonant structure, increasing the modal frequency of the structure in the first direction. When external acceleration is detected, the stiffness change rate of the cantilever beam 3 connected to the mass block 2 in the first direction of movement, thereby changing the sensitivity of the structure to changes in external acceleration. Under the drive of the external second electrode, after the locking assembly 6 is locked, the position of the mass block 2 in the vertical first direction is changed, thereby permanently changing the internal structure of the micro-electromechanical structure 100, forming a micro-electromechanical structure 100 with different designs and performances.

[0053] based on Figure 1 and Figure 2 The present invention further provides a method for controlling the mechanical properties of the micro-electromechanical structure 100, comprising the following steps:

[0054] Step S1, driving the mass block 2 to move in a vertical first direction;

[0055] Specifically, the electrodes are powered on to drive the mass block 2 to move in a vertical first direction. The first direction is the structural functional direction of the micro-electromechanical structure 100. When the micro-electromechanical structure 100 is an actuator, the first direction is the reciprocating motion direction of the mass block 2, and when the micro-electromechanical structure 100 is a sensor, the first direction is the detection direction.

[0056] Step S2 : the locking assembly 6 locks the position of the mass block 2 in a first direction perpendicular to the mass block 2 , so that the mass block 2 stops moving and the mechanical properties of the micro-electromechanical structure 100 in the first direction change.

[0057] When the displacement of the mass block 2 in the first direction perpendicular to the vertical direction increases to trigger the locking of the two parts of the locking assembly 6, so that the partial locking assembly on the mass block 2 is locked with the other partial locking assembly on the movement path of the mass block 2 in the first direction perpendicular to the vertical direction, the mass block 2 stops moving in the first direction perpendicular to the vertical direction after being connected and fixed to the other partial locking assembly on the movement path in the first direction, and the mechanical properties of the micro-electromechanical structure in the first direction change.

[0058] Specifically, the locking assembly 6 includes a lock buckle 61 provided on the mass block 2 and a lock slot 62 provided on the substrate 1 and engaged with the lock buckle 61. Optionally, the lock buckle 61 includes a connecting rod 611 extending from the mass block 2 toward the lock slot 62 and a lock head 612 provided at one end of the connecting rod 611 away from the mass block 2, and the lock head 612 is a triangle with its head facing the lock slot 62. The lock slot 62 includes an anchor block 621 fixed on the substrate 1, two connecting arms 622 extending from the anchor block 621 toward the lock buckle 61, and a lock hook 623 from one side of the connecting arm 622 away from the anchor block 621, the two lock hooks 623 extend toward one side opposite to the other, and the two lock hooks 623, the two connecting arms 622 and the anchor block 621 surround a receiving cavity for receiving the lock head 612. When the second electrode 5 applies an external driving signal to the mass block 2, a force is given to the mass block 2 to move in the first direction perpendicular to the mass block 2. Under the action of this force, the lock buckle 61 on the mass block 2 moves toward the lock groove 62 on the substrate 1. If the applied force is large enough, the mass block 2 produces a sufficiently large displacement in the first direction perpendicular to the mass block 2, so that the lock head 612 of the lock buckle 61 can move into the accommodating cavity of the lock groove 62 under the action of acceleration. The lock head 612 is close to one end of the connecting rod 611 and abuts against the lock hook 623, so that the lock buckle 61 cannot return to its original position. The locking assembly 6 locks the mass block 2, thereby changing the position of the mass block 2 in the first direction perpendicular to the mass block 2, so as to change the internal structure and design of the micro-electromechanical structure 100.

[0059] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0060] The above embodiments only express the preferred implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for regulating the mechanical properties of a micro-electromechanical structure, characterized in that: The micro-electromechanical structure comprises: substrate; A mass block is disposed on the substrate; cantilever beams, at least one pair of the cantilever beams being disposed outside the mass block, one end of the cantilever beams being fixedly connected to the substrate and the other end of the cantilever beams being connected to the mass block, so as to suspend the mass block on the substrate; A first electrode, connected to the mass block via a capacitor, drives the mass block to reciprocate in a first direction or detects the movement acceleration of the mass block in the first direction; A second electrode, connected to the mass block via a capacitor, drives the mass block to move in a vertical first direction; A locking assembly, part of which is disposed on the mass block, and the other part of which is disposed on the substrate and is arranged opposite to the part disposed on the mass block, wherein the two parts of the locking assembly are disposed on a path of the mass block moving in a vertical first direction; The control method comprises: Powering up the second electrode to drive the mass block to move in a vertical first direction, wherein the first direction is a structural functional direction of the micro-electromechanical structure; When the displacement of the mass block in the vertical first direction increases to trigger the locking of the two parts of the locking assembly, the mass block is fixed to change the position of the mass block in the vertical first direction, thereby changing the mechanical properties of the micro-electromechanical structure.

2. The method for controlling the mechanical properties of a micro-electromechanical structure according to claim 1, characterized in that: The locking assembly comprises a lock buckle provided on the mass block and a lock slot provided on the substrate and engaged with the lock buckle; When the mass block moves in a vertical first direction, the lock buckle is driven to move into the lock slot, and the lock slot locks the lock buckle to fix the mass block.

3. The method for controlling the mechanical properties of a micro-electromechanical structure according to claim 2, characterized in that: The lock buckle comprises a connecting rod extending from the mass block toward the lock slot and a lock head disposed at one end of the connecting rod away from the mass block, wherein the lock head is a triangle with its head facing the lock slot. The lock slot includes an anchor block fixed on the substrate, two connecting arms extending from the anchor block toward the lock buckle, and a lock hook from the connecting arm away from the anchor block. The two lock hooks extend toward the opposite side, and the two lock hooks, the two connecting arms and the anchor block surround a receiving cavity for receiving the lock head.

4. The method for controlling the mechanical properties of a micro-electromechanical structure according to claim 2, characterized in that: At least one of the lock buckle and the lock groove can be elastically deformed in the first direction.

5. The method for controlling the mechanical properties of a micro-electromechanical structure according to claim 2, characterized in that: The mass block is square, and the four cantilever beams are connected to the four vertices of the mass block in a one-to-one correspondence.

6. The method for controlling the mechanical properties of a micro-electromechanical structure according to claim 1, characterized in that: The cantilever beam comprises an anchor point arranged on the substrate and an elastic element connecting the anchor point and the vertex of the mass block. When at rest, the elastic elements of the four cantilever beams have the same length.

7. The method for controlling the mechanical properties of a micro-electromechanical structure according to claim 1, characterized in that: The first movable comb teeth are respectively arranged on both sides of the mass block extending along the first direction. The first electrode comprises a first fixed block fixed on the substrate and first fixed comb teeth arranged on the first fixed block. The first fixed comb teeth extend into the gaps of the first movable comb teeth.

8. The method for controlling the mechanical properties of a micro-electromechanical structure according to claim 1, characterized in that: The second movable comb teeth are respectively arranged on both sides of the mass block extending along the perpendicular first direction. The second electrode comprises a second fixed block fixed on the substrate and second fixed comb teeth arranged on the second fixed block. The second fixed comb teeth extend into the gaps of the second movable comb teeth.

9. The method for controlling the mechanical properties of a micro-electromechanical structure according to claim 1, characterized in that: The second electrodes include two electrodes that are symmetrically arranged.

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