A MEMS element

Abstract

This invention discloses a MEMS element, including a backplate and a diaphragm disposed opposite to the backplate, with a predetermined gap between the diaphragm and the backplate. The backplate has a protrusion on the side facing the diaphragm. The diaphragm has an additional material layer defining a reinforcing region on the diaphragm. Along the vibration direction of the diaphragm, the orthographic projection of the protrusion onto the diaphragm falls within the reinforcing region. Furthermore, along the vibration direction of the diaphragm, the orthographic projection of the protrusion onto the diaphragm does not overlap with the additional material layer. Compared with the prior art, this invention reduces local bending and deformation around the contact points of the diaphragm during forced contact by adding an additional material layer located around the contact points. This reduction in bending lowers the maximum stress experienced by the diaphragm at the contact points, thereby improving mechanical robustness and reducing the likelihood of crack formation.

Description

Technical Field

[0001] This invention relates to the field of microelectromechanical systems (MEMS) technology, and in particular to a MEMS element. Background Technology

[0002] In MEMS microphones, the diaphragm is subjected to pressure shocks, which push the diaphragm into contact with a backplate. The backplate itself restricts the diaphragm's movement. To prevent adhesion between the diaphragm and the backplate, the side of the backplate facing the diaphragm has multiple protrusions. This reduces the contact area between the backplate and the diaphragm, thus reducing adhesive energy. However, these protrusions can cause stress concentration at contact points within the diaphragm, often leading to damage and crack propagation through the diaphragm. Summary of the Invention

[0003] The purpose of this invention is to provide a MEMS element that solves the technical problems in the prior art and can reduce the possibility of crack formation.

[0004] This invention provides a MEMS element, including a backplate and a diaphragm disposed opposite to the backplate, wherein a predetermined gap exists between the diaphragm and the backplate, wherein: The back plate has a protrusion on the side facing the diaphragm; The diaphragm has an additional material layer that defines a reinforcing region on the diaphragm. Along the vibration direction of the diaphragm, the orthographic projection of the protrusion on the diaphragm falls within the reinforcing region. Furthermore, along the vibration direction of the diaphragm, the orthographic projection of the protrusion on the diaphragm does not overlap with the additional material layer.

[0005] In a MEMS element as described above, preferably, the additional material layer is a ring structure, and the reinforcing region is formed inside the ring structure.

[0006] In a MEMS element as described above, preferably, the additional material layer is a strip structure, and the reinforcing region is formed between two additional material layers.

[0007] In a MEMS element as described above, preferably, the additional material layer is a closed-end curved structure, and the reinforcing region is formed inside the curved structure.

[0008] In a MEMS element as described above, preferably, the additional material layer includes a first portion and a second portion, the first portion being a ring structure, the second portion being located within the ring structure, and the reinforcing region being formed between the inner surface of the first portion and the outer surface of the second portion.

[0009] In a MEMS element as described above, preferably, the diaphragm has a receiving cavity on the side opposite to the backplate, and the additional material layer is embedded in the receiving cavity.

[0010] In a MEMS element as described above, preferably, the additional material layer protrudes from the side of the diaphragm facing the backplate.

[0011] In a MEMS element as described above, preferably, the additional material layer protrudes from the side of the diaphragm opposite to the backplate.

[0012] In a MEMS element as described above, preferably, the internal stress of the additional material layer is greater than the internal stress of the diaphragm.

[0013] In the MEMS element described above, preferably, the diaphragm is made of polycrystalline silicon and the additional material layer is made of SiN.

[0014] Compared with the prior art, the present invention reduces the local bending and deformation of the diaphragm when forced into contact by adding an additional material layer to the diaphragm, which is located around the contact point of the diaphragm. The reduction of bending reduces the maximum stress experienced by the diaphragm at the contact point, thereby improving mechanical robustness and reducing the possibility of crack formation. Attached Figure Description

[0015] Figure 1 This is a cross-sectional schematic diagram of a MEMS element with the first structure provided in the embodiments of the present invention; Figure 2 This is a cross-sectional schematic diagram of a MEMS element with the second structure provided in an embodiment of the present invention; Figure 3 This is a cross-sectional schematic diagram of a MEMS element with the third structure provided in the embodiments of the present invention; Figure 4 This is a schematic diagram of the protrusion and the additional material layer in a first mating state provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the protrusion and the additional material layer in a second mating state provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of the additional material layer in the fourth feasible embodiment provided by the present invention; Figure 7 This is a schematic diagram of the protrusion in the fourth feasible embodiment provided by the present invention.

[0016] Explanation of reference numerals in the attached figures: 10-Back plate, 11-Protrusion; 20-Diaphragm, 21-Additional material layer, 211-First part, 212-Second part, 22-Reinforcing region; 23-Receiving cavity. Detailed Implementation

[0017] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0018] Reference Figures 1 to 3 As shown, the present invention provides a MEMS element, including a backplate 10 and a diaphragm 20 disposed opposite to the backplate 10, wherein a predetermined gap exists between the diaphragm 20 and the backplate 10, wherein: The back plate 10 has a protrusion 11 on the side facing the diaphragm 20. When the diaphragm 20 is subjected to pressure impact, the pressure impact pushes the diaphragm 20 to contact the protrusion 11. The end of the protrusion 11 facing away from the back plate 10 forms a contact point on the diaphragm 20.

[0019] The diaphragm 20 has an additional material layer 21, which defines a reinforcing region 22 on the diaphragm 20. The position and size of this reinforcing region 22 are determined by the position and size of the additional material layer 21. The additional material layer 21 is located on the periphery of the reinforcing region 22. Along the vibration direction of the diaphragm 20, the orthographic projection of the protrusion 11 on the diaphragm 20 falls within the reinforcing region 22; and along the vibration direction of the diaphragm 20, the orthographic projection of the protrusion 11 on the diaphragm 20 does not overlap with the additional material layer 21. When the protrusion 11 contacts the diaphragm 20, the contact point of the protrusion 11 on the diaphragm 20 is located within the reinforcing region 22. The additional material layer 21 strengthens the diaphragm 20 around the contact point, making it more rigid, thereby reducing the local bending and deformation of the diaphragm 20 when forced into contact. The reduction in bending reduces the maximum stress experienced by the diaphragm 20 in the reinforcing region 22, thereby improving mechanical robustness and reducing the possibility of crack formation. If a crack forms in the reinforced region 22, the additional material layer 21 can also limit the crack propagation.

[0020] In the first feasible implementation method, refer to Figure 4As shown, the additional material layer 21 has a ring-shaped structure, and the reinforcing region 22 is formed inside the ring-shaped structure. When the protrusion 11 contacts the diaphragm 20, the contact point of the protrusion 11 on the diaphragm 20 is located inside the ring-shaped structure. The ring-shaped structure can effectively enhance the rigidity and stability of the diaphragm 20. Due to the symmetry and uniform distribution of the ring-shaped structure, it can more evenly distribute the force generated during contact when the reinforcing region 22 of the diaphragm 20 contacts the protrusion 11 of the back plate 10. The force will be concentrated at the edge and inner area of ​​the ring-shaped structure, thereby reducing stress concentration at a single point and reducing the possibility of crack formation. At the same time, if a crack forms in the reinforcing region 22, the ring-shaped structure can limit the crack propagation, thereby improving the durability and reliability of the diaphragm 20.

[0021] In the second feasible implementation method, refer to Figure 5 As shown, the additional material layer 21 has a strip structure, and the reinforcing region 22 is formed between the two additional material layers 21. Correspondingly, the protrusion 11 also has a strip structure. When the protrusion 11 contacts the diaphragm 20, the contact point of the protrusion 11 on the diaphragm 20 is located between the two additional material layers 21. The strip structure of the additional material layer 21 can provide additional stiffness in the reinforcing region 22 of the diaphragm 20. When the protrusion 11 contacts the diaphragm 20, the contact point located between the two additional material layers 21 will be more strongly supported, thereby reducing local deformation and bending in this area. If a crack forms in the reinforcing region 22, the strip structure of the additional material layer 21 can play a certain limiting role, preventing the crack from propagating in other directions of the diaphragm 20, thereby improving the mechanical robustness of the diaphragm 20. At the same time, the design of the strip structure can control the vibration mode of the diaphragm 20 to a certain extent. By adjusting the position, number, and spacing of the strip structure, the vibration characteristics of the diaphragm 20 can be optimized, enabling it to exhibit better performance in a specific frequency range.

[0022] In a third feasible implementation, the additional material layer 21 is a closed-end curved structure, and the reinforcing region 22 is formed inside the curved structure. Preferably, the extension direction of the protrusion 11 is parallel to the extension direction of the additional material layer 21, and the contact point of the protrusion 11 on the diaphragm 20 is located inside the curved structure. The closed-end curved structure can provide additional stiffness support within the reinforcing region 22 of the diaphragm 20, effectively enhancing the rigidity of the diaphragm 20 inside the curved structure, thereby reducing local deformation and bending of the reinforcing region 22. The force exerted on the diaphragm 20 by the protrusion 11 can be better dispersed inside the curved structure, reducing stress concentration and thus reducing the risk of crack formation. Even if cracks form within the reinforcing region 22, the curved structure can still play a certain limiting role, preventing the cracks from propagating along other directions of the diaphragm 20. Meanwhile, by adding a curved structure to the diaphragm 20, the vibration mode of the diaphragm 20 can be optimized, the response performance of the diaphragm 20 in a specific frequency range can be improved, thereby improving the overall acoustic performance, helping to reduce the nonlinear deformation of the diaphragm 20 during vibration, thereby reducing acoustic distortion and improving the clarity and accuracy of the sound.

[0023] In the fourth feasible implementation method, refer to Figure 6 As shown, the additional material layer 21 includes a first portion 211 and a second portion 212. The first portion 211 has a ring-shaped structure, and the second portion 212 is located within the ring-shaped structure. A reinforcing region 22 is formed between the inner surface of the first portion 211 and the outer surface of the second portion 212. Preferably, the second portion 212 has a circular structure. (Refer to...) Figure 7 As shown, the protrusion 11 has a ring-shaped structure. The contact point of the protrusion 11 on the diaphragm 20 is located between the inner surface of the first part 211 and the outer surface of the second part 212. The first part 211 and the second part 212 provide a dual reinforcement effect. The combination of the ring-shaped first part 211 and the circular second part 212 can effectively disperse stress and reduce stress concentration, thereby reducing the risk of crack formation. Even if a crack is formed in the reinforced area 22, this structure can play a certain limiting role, confining the crack within the reinforced area 22, thereby improving the overall reliability of the diaphragm 20.

[0024] In the embodiments provided by the present invention, there are various ways to fix the additional material layer 21 and the diaphragm 20. Three fixing methods are listed below. Those skilled in the art can make more variations based on this, and no limitation is made here.

[0025] Reference Figure 1As shown, in the first fixing method, a receiving cavity 23 is provided on the side of the diaphragm 20 facing away from the back plate 10, and the additional material layer 21 is embedded in the receiving cavity 23. This can effectively enhance the structural strength and stability of the diaphragm 20, while optimizing stress distribution, reducing mechanical damage and nonlinear distortion under high sound pressure, balancing the local reinforcement effect, and not itself becoming a cause of stress concentration at the edge of the additional material. In a feasible embodiment, the radius of the receiving cavity 23 is on the order of 1 micrometer, the diameter of the additional material layer 21 is several micrometers, and the thickness is about 1 micrometer.

[0026] Reference Figure 2 As shown, in the second fixing method, the additional material layer 21 protrudes from the side of the diaphragm 20 facing the back plate 10. When the diaphragm 20 is subjected to pressure impact, the pressure impact pushes the diaphragm 20 to contact the protrusion 11. The contact point of the protrusion 11 on the diaphragm 20 is located within the reinforcement area 22. When the diaphragm 20 is forced to contact, it will bend locally. The additional material layer 21 is set on the side of the diaphragm 20 facing the back plate 10. On the one hand, it can strengthen the diaphragm 20 around the contact point, improve the rigidity of the diaphragm 20, and reduce the deformation around the contact point. On the other hand, it can also be used to abut against the back plate 10 or other components, effectively preventing the diaphragm 20 from sticking to the back plate 10 or other components, thereby improving the reliability and service life of the device.

[0027] Reference Figure 3 As shown, in the third fixing method, the additional material layer 21 protrudes from the side of the diaphragm 20 away from the back plate 10. When the diaphragm 20 is subjected to pressure impact, the pressure impact pushes the diaphragm 20 to contact the protrusion 11. The contact point of the protrusion 11 on the diaphragm 20 is located in the reinforcement area 22. When the diaphragm 20 is forced to contact, it will bend locally. The additional material layer 21 is set on the back of the diaphragm 20, which can strengthen the diaphragm 20 around the contact point, improve the rigidity of the diaphragm 20, and reduce the deformation around the contact point.

[0028] In the embodiments provided by the present invention, the internal stress of the additional material layer 21 is greater than the internal stress of the diaphragm 20. When no external force is applied, the additional material layer 21 will generate a certain preload on the diaphragm 20 due to its higher internal stress. When a pressure impact is applied to the diaphragm 20, this internal stress difference will cause the diaphragm 20 to deform more in accordance with the stress distribution of the additional material layer 21 when interacting with the additional material layer 21.

[0029] Preferably, the diaphragm 20 is made of polycrystalline silicon, and the additional material layer 21 is made of SiN, which has a higher Young's modulus and fracture strength than polycrystalline silicon. Due to its higher Young's modulus, the additional material layer 21 has a stronger resistance to elastic deformation and can provide stronger support for the diaphragm 20 when subjected to pressure impact. The high fracture strength of the additional material layer 21 allows it to withstand greater stress without cracking. When used with the diaphragm 20, even if the diaphragm 20 undergoes significant local bending deformation under pressure impact, the additional material layer 21 can maintain its integrity and use its high internal stress and high rigidity to constrain the deformation of the diaphragm 20, preventing excessive bending and damage to the diaphragm 20.

[0030] The above description, based on the embodiments shown in the figures, details the structure, features, and effects of the present invention. The above description is only a preferred embodiment of the present invention, but the present invention is not limited to the scope of implementation shown in the figures. Any changes made in accordance with the concept of the present invention, or equivalent embodiments modified to have equivalent changes, that do not exceed the spirit covered by the specification and figures, should be within the protection scope of the present invention.

Claims

1. A MEMS element, comprising a backplate and a diaphragm disposed opposite to the backplate, wherein a predetermined gap exists between the diaphragm and the backplate, characterized in that: The back plate has a protrusion on the side facing the diaphragm; The diaphragm has an additional material layer that defines a reinforcing region on the diaphragm. Along the vibration direction of the diaphragm, the orthographic projection of the protrusion on the diaphragm falls within the reinforcing region. Furthermore, along the vibration direction of the diaphragm, the orthographic projection of the protrusion on the diaphragm does not overlap with the additional material layer.

2. The MEMS element according to claim 1, characterized in that, The additional material layer has a ring-shaped structure, and the reinforcing region is formed inside the ring-shaped structure.

3. The MEMS element according to claim 1, characterized in that, The additional material layer has a strip structure, and the reinforcing region is formed between two additional material layers.

4. The MEMS element according to claim 1, characterized in that, The additional material layer is a closed-ended curved structure, and the reinforcing region is formed inside the curved structure.

5. The MEMS element according to claim 1, characterized in that, The additional material layer includes a first part and a second part, the first part being a ring structure, the second part being located within the ring structure, and the reinforcing region being formed between the inner surface of the first part and the outer surface of the second part.

6. The MEMS element according to claim 1, characterized in that, The diaphragm has a receiving cavity on the side opposite to the back plate, and the additional material layer is embedded in the receiving cavity.

7. The MEMS element according to claim 1, characterized in that, The additional material layer protrudes from the side of the diaphragm facing the backplate.

8. The MEMS element according to claim 1, characterized in that, The additional material layer protrudes from the side of the diaphragm opposite to the back plate.

9. The MEMS element according to claim 1, characterized in that, The internal stress of the additional material layer is greater than the internal stress of the diaphragm.

10. The MEMS element according to claim 9, characterized in that, The diaphragm is made of polycrystalline silicon, and the additional material layer is made of SiN.

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