Micro-electro-mechanical system structure

Abstract

A micro-electro-mechanical system structure is disclosed. The micro-electro-mechanical system structure includes a substrate and a back plate. The substrate has an opening portion, and the back plate is disposed on one side of the substrate. The micro-electro-mechanical system structure also includes a diaphragm disposed between the substrate and the back plate. The opening portion of the substrate is located below the diaphragm, and an air gap is formed between the diaphragm and the back plate. The micro-electro-mechanical system structure further includes a post structure and a protection post structure. The post structure is connected to the back plate and the diaphragm, and the protection post structure extends from the back plate into the air gap. In a top view of the back plate, the protection post structure surrounds the post structure.

Description

Technical Field

[0001] This invention relates to an acoustic transducer, and more particularly to a micro-electro-mechanical system (MEMS) structure that can be used in a micro-electro-mechanical system microphone. Background Technology

[0002] The current trend in personal electronics is towards manufacturing thin, compact, lightweight, and high-performance electronic devices, including microphones. Microphones are used to receive sound waves and convert audio signals into electrical signals. Microphones are widely used in everyday life and installed in electronic products such as telephones, mobile phones, and voice recorders. In a condenser microphone, changes in acoustic pressure (i.e., localized pressure deviations in ambient atmospheric pressure caused by sound waves) cause a corresponding deformation of the diaphragm, and this deformation leads to changes in capacitance. Therefore, changes in sound pressure can be obtained by detecting the voltage changes caused by these capacitance changes.

[0003] Unlike traditional electret condenser microphones (ECMs), microelectromechanical system (MEMS) microphones integrate their mechanical and electronic components onto semiconductor materials using integrated circuit (IC) technology to create miniature microphones. MEMS microphones offer advantages such as small size, lightweight design, and low power consumption, making them the mainstream choice for miniature microphones.

[0004] While existing microelectromechanical system (MEMS) microphones are generally adequate for their intended purpose, they do not fully meet other requirements. For example, the diaphragm of an MEMS microphone vibrates and deforms when sound pressure is applied. During air pressure testing, the diaphragm undergoes significant deformation, potentially leading to cracking of the MEMS microphone's sensor. Summary of the Invention

[0005] The microelectromechanical system (MEMS) structure of this invention can be used in MEMS microphones, comprising a protective pillar structure extending from a backplate into an air gap. In some embodiments, the protective pillar structure can reduce stress concentration around the pillar structure caused by diaphragm deformation, thereby preventing damage to the diaphragm under air pressure.

[0006] Some embodiments of the present invention include a microelectromechanical system (MEMS) structure. The MEMS structure includes a substrate and a backplate. The substrate has an opening, and the backplate is disposed on one side of the substrate. The MEMS structure also includes a diaphragm disposed between the substrate and the backplate. The opening of the substrate is located below the diaphragm, and an air gap is formed between the diaphragm and the backplate. The MEMS structure further includes a pillar structure and a protective pillar structure. The pillar structure connects the backplate and the diaphragm, while the protective pillar structure extends from the backplate into the air gap. In a top view of the backplate, the protective pillar structure surrounds the pillar structure.

[0007] In some embodiments, the protective column structure is separate from the diaphragm.

[0008] In some embodiments, in a top view of the back panel, the protective column structure is formed as a complete or incomplete closed pattern.

[0009] In some embodiments, in a top view of the back panel, the protective post structure is divided into multiple protective post sections.

[0010] In some embodiments, the back panel has a plurality of acoustic holes, and in a top view of the back panel, at least one of the acoustic holes is disposed between the column structure and the protective column structure.

[0011] In some embodiments, the microelectromechanical system (MEMS) structure further includes a support column structure that extends from the backplate into the air gap. In a top view of the backplate, the support column structure is positioned outside the protective column structure relative to the column structure.

[0012] In some embodiments, the microelectromechanical system (MEMS) structure further includes multiple bumps extending from the backplate into the air gap. The distance between the bumps and the diaphragm is greater than the distance between the protective post structure and the diaphragm.

[0013] In some embodiments, the backsheet includes a conductive layer and an insulating layer, with the insulating layer covering the conductive layer.

[0014] In some embodiments, the conductive layer is a conductive segment or is divided into multiple conductive segments, and the conductive segments are disconnected from each other in a cross-sectional view of the back sheet.

[0015] In some embodiments, the diaphragm includes a plurality of vent holes.

[0016] In some embodiments, the column structure corresponds to the center of the backplate and the center of the diaphragm.

[0017] In some embodiments, the protective pillar structure includes a conductive material or an insulating material.

[0018] In some embodiments, the protective column structure is a floating conductor or is at the same potential as the diaphragm. Attached Figure Description

[0019] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, according to industry standard practice, the various feature components are not drawn to scale. In fact, the dimensions of the various feature components may be enlarged or reduced to clearly demonstrate the technical features of the embodiments of the present invention.

[0020] Figure 1A and Figure 1B This is a partial cross-sectional view of a microphone for a microelectromechanical system (MEMS) according to some embodiments of the present invention;

[0021] Figure 1C This is a partial top view illustrating the backplate and diaphragm in some embodiments of the present invention;

[0022] Figure 2 and Figure 3 This is a partial top view illustrating the backplate and diaphragm, representing some other embodiments of the present invention.

[0023] Symbol Explanation

[0024] 10: Microelectromechanical System Structure

[0025] 11:Substrate

[0026] 11A: Opening portion

[0027] 12: Dielectric layer

[0028] 13: Back panel

[0029] 131: Conductive layer

[0030] 131S: Conductive section

[0031] 132: Insulation layer

[0032] 1321: First insulating layer

[0033] 1322: Second insulating layer

[0034] 133: Bump

[0035] 13A: Acoustic port

[0036] 14: Diaphragm

[0037] 14A: Vent

[0038] 15: Electrode layer

[0039] 16: Column Structure

[0040] 17: Protective column structure

[0041] 17S: Protective column section

[0042] 18: Support column structure

[0043] C13: Central axis of the backplate

[0044] C14: Central axis of the diaphragm

[0045] C16: Central axis of the column structure

[0046] d17: Distance between the protective column structure and the diaphragm

[0047] d18: Distance between the support column structure and the diaphragm

[0048] d133: Distance between the bump and the diaphragm

[0049] G: Air gap

[0050] M: Microelectromechanical systems microphone Detailed Implementation

[0051] The following disclosure provides many different embodiments or examples to implement different features of this invention. Specific examples of the various components and their arrangements described below are provided to simplify the invention. Of course, these are merely examples and not intended to be limiting. For example, if it is stated that a first feature is formed on or above a second feature, it may include embodiments where the first and second feature are in direct contact, or embodiments where other feature is formed between the first and second feature, so that the first and second feature may not be in direct contact.

[0052] It should be understood that other operational steps may be performed before, between, or after the method, and in other embodiments of the method, some operational steps may be replaced or omitted.

[0053] Furthermore, spatially related terms such as "below," "under," "down," "above," "above," and similar terms may be used herein to facilitate the description of the relationship between one element or feature and other elements or features in the accompanying drawings. These spatially related terms encompass different orientations of the device in use or operation, as well as the orientations described in the accompanying drawings. The device may be turned to different orientations (rotated 90 degrees or other orientations), and the spatially related adjectives used herein will be interpreted in accordance with the orientation after the turn.

[0054] In this invention, the terms "about," "approximately," and "substantially" generally mean within 20%, 10%, 5%, 3%, 2%, 1%, or even 0.5% of a given value. The given values ​​in this invention are approximate values. That is, even without a specific description of "about," "approximately," or "substantially," the given value may still include the meaning of "about," "approximately," or "substantially."

[0055] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It should be understood that these terms, such as those defined in commonly used dictionaries, should be interpreted in a meaning consistent with the context of the relevant art and will not be interpreted in an idealized or overly formal manner, unless specifically defined in the embodiments of the invention.

[0056] The same reference numerals and / or designations may be used repeatedly in the following embodiments. These repetitions are for simplification and clarity and are not intended to limit any specific relationship between the various embodiments and / or structures discussed.

[0057] Figure 1A and Figure 1B This is a partial cross-sectional view of a microelectromechanical system (MEMS) microphone M according to some embodiments of the present invention. For example, the MEMS microphone M may be a condenser microphone. Figure 1A and Figure 1B As shown, the microelectromechanical system (MEMS) microphone M includes a MEMS structure 10. In some embodiments, the MEMS structure 10 includes a substrate 11, a dielectric layer 12, a backplate 13, a diaphragm 14, and an electrode layer 15. It should be noted that, for the sake of simplicity... Figure 1A and Figure 1B Some components of the microelectromechanical system microphone M (microelectromechanical system structure 10) have been omitted.

[0058] The substrate 11 is used to support the dielectric layer 12, backplate 13, diaphragm 14, and electrode layer 15 located on one side of the substrate 11. For example... Figure 1A and Figure 1B As shown, in some embodiments, substrate 11 has an opening 11A. The opening 11A allows sound waves received by the microelectromechanical system microphone M to pass through and / or enter the microelectromechanical system structure 10. For example, substrate 11 may contain silicon or the like, but the embodiments of the present invention are not limited thereto.

[0059] A dielectric layer 12 is disposed between the substrate 11 and the diaphragm 14, and between the diaphragm 14 and the backplate 13. In other words, the diaphragm 14 is inserted into the dielectric layer 12 to provide partial isolation between the substrate 11, the diaphragm 14, and the backplate 13. Furthermore, the dielectric layer 12 is disposed around the backplate 13 and the diaphragm 14, such that the backplate 13 and the diaphragm 14 are supported at their edges by the dielectric layer 12. The dielectric layer 12 may be made of silicon oxide or the like.

[0060] A backplate 13 is disposed on one side of the substrate 11. The backplate 13 may have sufficient stiffness to prevent bending or movement when sound waves pass through it. For example, the backplate 13 may be a rigid perforated element, but this embodiment of the invention is not limited thereto. Figure 1A and Figure 1B As shown, in some embodiments, the back panel 13 includes a plurality of acoustic holes 13A, each of which extends through the back panel 13. The acoustic holes 13A are configured to allow sound waves to pass through.

[0061] like Figure 1A and Figure 1B As shown, the backplate 13 includes a conductive layer 131 and an insulating layer 132, with the insulating layer 132 covering the conductive layer 131 to provide protection. The insulating layer 132 may further include a first insulating layer 1321 and a second insulating layer 1322. Figure 1A and Figure 1B As shown, conductive layer 131 may be disposed on dielectric layer 12, first insulating layer 1321 may be disposed on conductive layer 131, and second insulating layer 1322 may be disposed on first insulating layer 1321. For example, conductive layer 131 may contain polysilicon or the like, and insulating layer 132 (e.g., first insulating layer 1321 and second insulating layer 1322) may contain silicon nitride or the like, but the embodiments of the present invention are not limited thereto. Furthermore, first insulating layer 1321 and second insulating layer 1322 may contain the same material or different materials.

[0062] like Figure 1A and Figure 1B As shown, in some embodiments, the conductive layer 131 is divided into multiple conductive segments 131S, and the conductive segments 131 are disconnected from each other in the cross-sectional view of the back plate 13, but the embodiments of the present invention are not limited thereto. In some other embodiments, the conductive layer 131 is a single (complete) conductive segment 131S.

[0063] The microelectromechanical system (MEMS) structure 10 can be electrically connected to a circuit (not shown) via multiple electrode pads of electrode layer 15, which is disposed on backplate 13 and electrically connected to conductive layer 131 and diaphragm 14. For example, electrode layer 15 may comprise copper, silver, gold, aluminum, the like, their alloys, or combinations thereof.

[0064] A diaphragm 14 is disposed between a substrate 11 and a backplate 13, with the opening 11A of the substrate 11 located below the diaphragm 14. The diaphragm 14 is movable or displaceable relative to the backplate 13. The diaphragm 14 is configured to sense sound waves received by a microelectromechanical system (MEMS) microphone M. Figure 1A and Figure 1B As shown, in some embodiments, the diaphragm 14 includes ventilation holes 14A, and an air gap G is formed between the diaphragm 14 and the back plate 13. Sound waves pass through the diaphragm 14 through the ventilation holes 14A to reach the air gap G, and then pass through the back plate 13 through the acoustic holes 13A.

[0065] More specifically, the displacement of the diaphragm 14 relative to the back plate 13 causes a change in capacitance between the diaphragm 14 and the back plate 13. This capacitance change is then converted into an electrical signal by the circuit connected to the diaphragm 14 and the back plate 13, and this electrical signal is sent out of the microelectromechanical system microphone M through the electrode layer 15.

[0066] On the other hand, to improve the sensitivity of the diaphragm 14, multiple vent holes 14A can be provided in the diaphragm 14 to reduce the rigidity of the diaphragm 14. In some embodiments, more than two vent holes 14A may be present. Utilizing this structural feature, high sensitivity of the microelectronic system microphone M can be achieved. Furthermore, the vent holes 14A in the diaphragm 14 are also configured to release high air pressure on the diaphragm 14.

[0067] In some embodiments, the microelectromechanical system (MEMS) structure 10 includes a pillar structure 16 connected to a backplate 13 and a diaphragm 14. More specifically, the pillar structure 16 may be in direct contact with the backplate 13 (e.g., conductive layer 131) and the diaphragm 14. For example, the pillar structure 16 may comprise an insulating material, such as silicon oxide, but this embodiment of the invention is not limited thereto.

[0068] like Figure 1A As shown, in some embodiments, the pillar structure 16 corresponds to the center of the back plate 13 and the center of the diaphragm 14. That is, the pillar structure 16 can be connected to the center of the back plate 13 and the center of the diaphragm 14, but the embodiments of the present invention are not limited thereto.

[0069] like Figure 1BAs shown, in some embodiments, the pillar structure 16 is offset from the center of the backplate 13 and the center of the diaphragm 14. More specifically, the central axis C16 of the pillar structure 16 is separate from the central axis C13 of the backplate 13. Similarly, the central axis C16 of the pillar structure 16 is separate from the central axis C14 of the diaphragm 14.

[0070] In some embodiments, the column structure 16 is a hollow structure. That is, the column structure 16 has internal space, but this is not a limitation of the embodiments of the present invention. In some other embodiments, the column structure 16 is a solid structure. The column structure 16 can reduce stress concentration on the diaphragm 14 and protect the diaphragm from damage.

[0071] In some embodiments, the microelectromechanical system structure 10 further includes a protective pillar structure 17 that extends from the backplate 13 into the air gap G. For example... Figure 1A and Figure 1B As shown, in some embodiments, the protective pillar structure 17 is separate from the diaphragm 14. In some embodiments, the protective pillar structure 17 comprises a conductive material (e.g., a semiconductor material, such as silicon (Si) or germanium (Ge)) or an insulating material (e.g., silicon nitride).

[0072] For example, such as Figure 1A and Figure 1B As shown, the protective pillar structure 17 may include a central silicon nitride portion and a silicon layer surrounding the silicon nitride portion, but this embodiment of the invention is not limited thereto. In other examples, the protective pillar structure 17 may be an entire insulating pillar or an entire conductive pillar, which may be adjusted according to actual needs.

[0073] In some embodiments, the microelectromechanical system structure 10 further includes a support column structure 18 that extends from the backplate 13 into the air gap G. For example... Figure 1A and Figure 1B As shown, in some embodiments, the support column structure 18 is separate from the diaphragm 14. The support column structure 18 may contain the same or similar material as the protective column structure 17.

[0074] Similarly, such as Figure 1A and Figure 1B As shown, the support pillar structure 18 may include a central silicon nitride portion and a silicon layer surrounding the silicon nitride portion, but this embodiment of the invention is not limited thereto. In other examples, the support pillar structure 18 may be an entire insulating pillar or an entire conductive pillar, which can be adjusted according to actual needs.

[0075] In some embodiments, the microelectromechanical system structure 10 further includes a plurality of dimples 133 extending from the backplate 13 into the air gap G. For example... Figure 1A and Figure 1BAs shown, in some embodiments, the distance d133 between the protrusion 133 and the diaphragm 14 is greater than the distance d17 between the protective pillar structure 17 and the diaphragm 14. Similarly, the distance d133 between the protrusion 133 and the diaphragm 14 is greater than the distance d18 between the support pillar structure 18 and the diaphragm 14. In other words, the protrusion 133 is further away from the diaphragm 14 than either the protective pillar structure 17 or the support pillar structure 18.

[0076] In some embodiments, at least one protrusion 133 is disposed between the protective post structure 17 and the support post structure 18. Figure 1A and Figure 1B In the illustrated embodiment, all the protrusions 133 are disposed between the protective column structure 17 and the support column structure 18, but the embodiments of the present invention are not limited thereto.

[0077] Figure 1C This is a partial top view illustrating the backplate 13 and diaphragm 14 according to some embodiments of the present invention, which shows the relationship between the acoustic aperture 13A, the column structure 16, the protective column structure 17, and the support column structure 18. It should be noted that... Figure 1C It may not completely correspond to Figure 1A And for the sake of brevity, Figure 1C Some components have been omitted.

[0078] Reference Figure 1C In some embodiments, in a top view of the backplate 13, the protective post structure 17 surrounds the upright structure 16. For example... Figure 1C As shown, in some embodiments, the protective column structure 17 is divided into multiple protective column segments 17S, and the protective column segments 17S are separated from each other, but the embodiments of the present invention are not limited thereto.

[0079] like Figure 1C As shown, in some embodiments, in a top view of the back plate 13, at least one sound hole 13A is disposed between the column structure 16 and the protective column structure 17, and at least one sound hole 13A is disposed between the protective column structure 17 and the support column structure 18.

[0080] like Figure 1C As shown, in some embodiments, in a top view of the back plate 13, the support column structure 18 is disposed on the outside of the protective column structure 17 relative to the column structure 16, and the support column structure 18 surrounds the sound hole 13A.

[0081] In some embodiments, the protective pillar structure 17 and the support pillar structure 18 are floating conductors or have the same potential as the diaphragm 14. In other words, when the protective pillar structure 17 and the support pillar structure 18 are complete conductive pillars, the conductive pillars are floating conductors or have the same potential as the diaphragm 14.

[0082] For example, such as Figure 1CAs shown, the backplate 13 (conductive layer 131) and the diaphragm 14 can be electrically connected to the common electrode CE. When the protective pillar structure 17 and the support pillar structure 18 are complete conductive pillars, since the protective pillar structure 17 and the support pillar structure 18 are electrically connected to the conductive layer 131 of the backplate 13, they can have the same potential as the diaphragm 14.

[0083] Figure 2 and Figure 3 This is a partial top view illustrating the backplate 13 and diaphragm 14 according to some other embodiments of the present invention, which shows the relationship between the acoustic aperture 13A, the column structure 16, the protective column structure 17, and the support column structure 18. It should be noted that... Figure 2 and Figure 3 It may not completely correspond to Figure 1A And for the sake of brevity, Figure 2 and Figure 3 Some components have been omitted.

[0084] Reference Figure 2 In some embodiments, in a top view of the backplate 13, the protective post structure 17 surrounds the upright structure 16. For example... Figure 2 As shown, in some embodiments, the protective pillar structure 17 forms a complete closed pattern. For example, as Figure 2 As shown, the protective column structure 17 can be formed into a closed circle, but the embodiments of the present invention are not limited thereto.

[0085] In some other embodiments, the protective pillar structure 17 is formed as a non-complete closed pattern. (See also...) Figure 3 In some embodiments, in a top view of the back panel 13, the support column structure 18 is formed in a C-shaped pattern. For example... Figure 3 As shown, in some embodiments, each support column structure 18 partially surrounds (at least) two acoustic holes 13A, but the embodiments of the present invention are not limited thereto.

[0086] In summary, in the embodiments of the present invention, since the microelectromechanical system structure includes a protective column structure extending from the backplate into the air gap (in some embodiments, a support column structure), the stress concentration around the column structure can be effectively reduced (simulation tests show more than 40% stress relief), thereby preventing the diaphragm from being damaged under air pressure.

[0087] The foregoing outlines the features of several embodiments to enable those skilled in the art to better understand the viewpoints of the embodiments of the present invention. Those skilled in the art should understand that they can design or modify other manufacturing processes and structures based on the embodiments of the present invention to achieve the same purpose and / or advantages as the embodiments described herein. Those skilled in the art should also understand that such equivalent structures do not depart from the spirit and scope of the present invention, and that various changes, substitutions, and replacements can be made without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be defined by the appended claims. Furthermore, although the present invention has been disclosed above with reference to several embodiments, it is not intended to limit the present invention.

[0088] References to features, advantages, or similar language throughout this specification do not imply that all features and advantages achievable using this invention should or may be implemented in any single embodiment of the invention. Rather, language relating to features and advantages is to be understood as meaning that a particular feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the invention. Thus, the discussion of features and advantages, as well as similar language, throughout this specification may, but does not necessarily, represent the same embodiments.

[0089] Furthermore, in one or more embodiments, the features, advantages, and characteristics described in this invention can be combined in any suitable manner. Based on the description herein, those skilled in the art will recognize that the invention can be implemented without one or more specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be identified in certain embodiments that may not be present in all embodiments of the invention.

Claims

1. A microelectromechanical system (MEMS) architecture, comprising: The substrate has an opening. A back plate is disposed on one side of the substrate; A diaphragm is disposed between the substrate and the back plate, wherein the opening portion of the substrate is located below the diaphragm, and an air gap is formed between the diaphragm and the back plate. A column structure connects the back plate and the diaphragm; as well as The protective pillar structure and multiple protrusions extend from the back plate into the air gap. In the top view of the back panel, the protective pillar structure surrounds the upright structure, wherein the distance between the protrusions and the diaphragm is greater than the distance between the protective pillar structure and the diaphragm.

2. The microelectromechanical system structure as described in claim 1, wherein the protective pillar structure is separate from the diaphragm.

3. The microelectromechanical system structure as claimed in claim 1, wherein in the top view of the backplate, the protective column structure is formed as a complete or incomplete closed pattern.

4. The microelectromechanical system structure as claimed in claim 1, wherein in the top view of the backplate, the protective pillar structure is divided into multiple protective pillar sections.

5. The microelectromechanical system structure as claimed in claim 1, wherein the back plate has a plurality of acoustic holes, and in the top view of the back plate, at least one of the acoustic holes is disposed between the column structure and the protective column structure.

6. The microelectromechanical system architecture as described in claim 1, further comprising: A support column structure extends from the back plate into the air gap, wherein, in the top view of the back plate, the support column structure is positioned outside the protective column structure relative to the column structure.

7. The microelectromechanical system structure as claimed in claim 1, wherein the backplane includes a conductive layer and an insulating layer, the insulating layer covering the conductive layer.

8. The microelectromechanical system structure of claim 7, wherein the conductive layer is a conductive segment or is divided into multiple conductive segments, and the conductive segments are disconnected from each other in the cross-sectional view of the backplate.

9. The microelectromechanical system structure as claimed in claim 1, wherein the diaphragm includes a plurality of vent holes.

10. The microelectromechanical system structure as claimed in claim 1, wherein the column structure corresponds to the center of the backplate and the center of the diaphragm.

11. The microelectromechanical system structure as claimed in claim 1, wherein the protective pillar structure comprises a conductive material or an insulating material.

12. The microelectromechanical system structure as claimed in claim 1, wherein the protective column structure is a floating conductor or is at the same potential as the diaphragm.

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