MEMS device

Abstract

The present disclosure relates to a MEMS device comprising: a transducer element having a first deflectable membrane structure, a rigid electrode structure arranged between the first and second deflectable membrane structures, and a second deflectable membrane structure, in a vertically spaced configuration, the first and second deflectable membrane structures each comprising a deflectable portion, mechanically coupled to each other by a mechanical connection element, mechanically decoupled from the rigid electrode structure; a carrier element supporting the transducer element; a plurality of first clamping structures mechanically connecting the transducer element and the carrier element at clamping regions of an edge of the transducer element; an elongated structure extending laterally from an unclamped edge region of the transducer element; a plurality of second clamping structures mechanically connecting the elongated structure and the carrier element at clamping regions of an edge of the elongated structure; the elongated structure comprising a first elongated element (second elongated element) extending at least partially from the transducer element to the second clamping structure in the same plane as the first deflectable membrane structure (second deflectable membrane structure).

Description

Technical Field

[0001] Embodiments of this disclosure relate to MEMS devices (MEMS = Microelectromechanical Systems). More specifically, embodiments relate to the field of MEMS acoustic transducers (MEMS microphones or MEMS speakers), such as hermetically sealed dual-diaphragm (SDM) microphones or speakers with a half-bridge design, having a plurality of first clamping structures for connecting transducer elements to a carrier element, an elongation structure, and a plurality of second clamping structures for connecting the elongation structure to the carrier element. Background Technology

[0002] In implementing appropriate sensors within mobile devices, home automation systems (such as smart homes), and the automotive industry, it is becoming increasingly important to sense environmental parameters (such as sound) in the ambient atmosphere using MEMS-based devices. MEMS devices, such as MEMS acoustic transducers (MEMS microphones or MEMS speakers), essentially function as transducer elements, capacitively converting sound pressure waves into analog electrical signals. The sound transduction mechanism in a MEMS microphone involves a variable capacitor having a fixed plate (back plate or counter electrode) and at least one deflectable plate (film).

[0003] When designing capacitive MEMS devices (such as acoustic transducers (microphones or speakers)), achieving a high signal-to-noise ratio (SNR) for the transducer's output signal is typically desirable. The continued miniaturization of transducers may present new challenges regarding the desired high SNR.

[0004] With the further development of semiconductor technology, sealed dual-diaphragm (SDM) microphones have emerged to further improve key performance characteristics such as low noise and reliability. An SDM microphone typically includes a top diaphragm, a bottom diaphragm, a perforated stator, a top oxide structure between the top diaphragm's peripheral portion and the stator, a bottom oxide structure between the bottom diaphragm's peripheral portion and the stator, and at least one strut coupled between the top and bottom diaphragms. In conventional SDM MEMS microphones, the transducer element is mechanically anchored by another oxide structure along its entire periphery. However, because the diaphragm is anchored around its entire periphery, mechanical compliance and therefore the signal-to-noise ratio (SNR) can be limited. To increase diaphragm compliance, the diaphragm can be anchored only in specific areas. For example, in a "bridge"-like design, two sides of the cantilever are anchored, while the two long sides are free to move. However, this design can be susceptible to contamination from the environment, such as blockage (or clogging) of the free-moving side areas. This can lead to a significant deterioration in microphone operating characteristics, such as relatively low sensitivity and SNR, and further, relatively low robustness and durability.

[0005] Therefore, in the field of MEMS devices (e.g., MEMS transducers), there is a continuous demand for MEMS devices with further improved mechanical, operational, and electrical characteristics, for example, to provide further improved performance with increased sensitivity and / or SNR, which are less susceptible to (or more resistant to) contamination (e.g., contaminants from particulate matter) and thus avoid significant deterioration of their operational characteristics, and achieve improved robustness and durability.

[0006] This need can be addressed by the MEMS device according to independent claim 1. Furthermore, specific embodiments of the MEMS device are defined in the dependent claims. Summary of the Invention

[0007] According to an embodiment, a MEMS device includes a transducer element (e.g., a microphone or speaker) having a first deflectable film structure, a rigid electrode structure (e.g., a stator or backplate), and a second deflectable film structure arranged vertically at intervals. The rigid electrode structure is disposed between the first and second deflectable film structures, each including a deflectable portion, and the deflectable portions of the first and second deflectable film structures are mechanically coupled to each other by means of mechanical connecting elements (e.g., pillars or columns) and mechanically decoupled from the rigid electrode structure. The MEMS device also includes a carrier element for supporting the transducer element and a plurality of first clamping structures for mechanically connecting (e.g., anchoring or mechanically coupling) the transducer element to the carrier element at edge clamping regions (e.g., along) of the transducer element. The MEMS device also includes an elongated structure extending laterally from an unclamped edge region of the transducer element, and a plurality of second clamping structures for mechanically connecting (e.g., anchoring or mechanically coupling) the elongated structure to a carrier element at (e.g., along) the edge clamping region of the elongated structure. The elongated structure includes a first elongated element extending at least partially from the transducer element to the second clamping structure in the same plane as the first deflectable membrane structure; or, the elongated structure includes a second elongated element extending at least partially from the transducer element to the second clamping structure in the same plane as the second deflectable membrane structure.

[0008] According to an embodiment, the elongation structure may include a first elongation element that extends at least partially from the transducer element to the second clamping structure in the same plane as the first deflectable film structure, and the elongation structure may include a second elongation element that extends at least partially from the transducer element to the second clamping structure in the same plane as the second deflectable film structure.

[0009] According to an embodiment, the transducer element can be mechanically decoupled from the carrier element at the unclamped edge region.

[0010] According to an embodiment, the first elongation element can be formed as a lateral elongation of a first deflectable membrane structure.

[0011] According to an embodiment, the second elongation element can be formed as a lateral elongation of a second deflectable membrane structure.

[0012] According to an embodiment, the MEMS device may further include a wall structure at the unclamped edge region of the transducer element.

[0013] This disclosure describes MEMS devices, such as MEMS acoustic transducers, such as SDM MEMS microphones or speakers, with significantly increased mechanical compliance, resulting in significantly increased mechanical sensitivity (compared to conventional SDM microphones of the same physical size), and significantly increased robustness and durability, thus being relatively less susceptible to (or more resistant to) contamination, thereby avoiding significant deterioration of their operating characteristics.

[0014] Therefore, the MEMS device method of the present invention with a half-bridge (or half-bridge) design allows for relatively high compliance of membrane arrangements, particularly for sealed dual-membrane (SDM) microphones with two coupled membrane structures and elongation structures, while being more resistant to or less affected by (external) environmental contamination.

[0015] Therefore, MEMS devices with a half-bridge design (including elongated structures) can provide robust and contamination-resistant (e.g., particulate-resistant) MEMS devices, such as MEMS microphones, without relying on external protective structures (such as external environmental barriers) to prevent contaminants (e.g., particulate matter) from interfering with the operation of MEMS devices.

[0016] Therefore, MEMS devices achieve enhanced sensitivity and SNR, and increased robustness to external or environmental contamination, allowing for a better trade-off between the former and the latter. In other words, half-bridge designs (including elongated structures) provide improved and durable performance for MEMS devices such as SDM MEMS microphones. In particular, high mechanical compliance (also known as membrane compliance or mechanical sensitivity, defined as the amplitude of membrane displacement per unit incident sound pressure) and high robustness or durability are important properties for the high operational performance of SDM MEMS microphones. Attached Figure Description

[0017] In the following description, embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings:

[0018] Figures 1a-d show schematic top (plan) views, schematic oblique views, and two different schematic cross-sectional views of a MEMS device according to embodiments of the present disclosure;

[0019] Figures 2a-b show schematic cross-sectional views of a MEMS device according to another embodiment of the present disclosure, illustrating another exemplary implementation of the elongated structure;

[0020] Figures 3a-d illustrate schematic diagrams of different implementations of "stress relief structures" included in the elongation structure of a MEMS device according to another embodiment of the present disclosure; and

[0021] Figures 4a-d show schematic top (plan) views of a MEMS device according to another embodiment of the present disclosure, illustrating another exemplary implementation of a half-bridge design for a MEMS device (e.g., an SDM microphone).

[0022] Before discussing this embodiment in more detail with reference to the accompanying drawings, it should be noted that in the drawings and description, the same reference numerals or the same names are generally used for the same elements and elements having the same function and / or the same technical or physical effect, so that the descriptions of these elements and their functions shown in different embodiments can be interchanged or applied to different embodiments. Detailed Implementation

[0023] In the following description, embodiments will be discussed in detail; however, it should be understood that the embodiments provide many applicable concepts that can be embodied in a wide range of dual-film MEMS devices. The specific embodiments discussed are merely illustrative of specific ways of implementing and using the concepts and do not limit the scope of the embodiments. In the following description of the embodiments, the same reference numerals or the same names are used to identify elements that are the same or similar or have the same function, and repeated descriptions of elements having the same reference numerals or the same names are generally omitted. In the following description, several details are set forth to explain the embodiments of this disclosure more thoroughly.

[0024] However, it will be apparent to those skilled in the art that other embodiments may be implemented without these specific details. In other instances, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring the examples described herein. Furthermore, unless explicitly stated otherwise, features of the different embodiments described herein may be combined with each other.

[0025] It should be understood that when an element is referred to as "connected" or "coupled" to another element, it can be directly connected or coupled to that other element, or there may be an intermediate element. Conversely, when an element is referred to as "directly" connected to another element, "connected," or "coupled," there is no intermediate element. Other terms used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" vs. "directly between," "adjacent" vs. "directly adjacent," "on" vs. "directly on," etc.).

[0026] For ease of description of the various embodiments, the figures include a Cartesian coordinate system (x, y, z), where the xy plane corresponds to (i.e., parallel to) a first primary surface region of the carrier element (or substrate) (=reference plane=xy plane), where the vertically upward direction about the reference plane (xy plane) corresponds to the "+z" direction, and where the vertically downward direction about the reference plane (xy plane) corresponds to the "-z" direction. In the following description, the term "lateral" means a direction parallel to the x and / or y directions, i.e., parallel to the xy plane, and the term "vertical" means a direction parallel to the z direction.

[0027] In the following description, the thickness of a component typically indicates its dimension in the vertical direction. In the accompanying drawings, different components are not necessarily drawn to scale. Therefore, the dimensions of the different components illustrated are not necessarily drawn to scale.

[0028] In the description of the embodiments, terms and text paragraphs placed in parentheses (near the described element or function) should be understood as further explanations, exemplary configurations, exemplary supplements and / or exemplary alternatives to the described element or function.

[0029] Figure 1a shows an exemplary schematic top view (parallel to the xy plane) of the exemplary MEMS device 10, Figure 1b shows an exemplary schematic oblique view (tilted or at an angle to the xy plane), Figure 1c shows an exemplary schematic cross-sectional view (parallel to the xz plane) along section line AA' (= cross-sectional plane 1) of the exemplary MEMS device 10, and Figure 1d shows an exemplary schematic cross-sectional view (parallel to the yz plane) along another section line BB' (= cross-sectional plane 2) of the exemplary MEMS device 10.

[0030] As shown in Figures 1a-d, the MEMS device 10 includes (sound) transducer elements (e.g., acoustic transducer elements, such as microphone elements or speaker elements) 12, which have a first deflectable film structure 14, a rigid electrode structure (e.g., a stator or backplate) 16, and a second deflectable film structure 18 arranged vertically spaced apart, wherein the rigid electrode structure 16 is disposed between the first deflectable film structure 14 and the second deflectable film structure 18. The first deflectable film structure 14 and the second deflectable film structure 18 each include deflectable portions 14-1 and 18-1, and the deflectable portions 14-1 of the first deflectable film structure 14 and 18-1 of the second deflectable film structure 18 are mechanically coupled to each other by means of mechanical connecting elements (e.g., in the form of pillars or columns) 20, and are mechanically decoupled from the rigid electrode structure 16 (with respect to its deflectability).

[0031] MEMS device 10 also includes a carrier element 22 for supporting (e.g., mechanically bearing) the transducer element 12. The carrier element 22 may include a substrate or a semiconductor (e.g., Si) substrate. MEMS device 10 also includes a plurality of first clamping structures (or, e.g., anchoring structures) 24-1, 24-2 for mechanically connecting (e.g., anchoring) the transducer element 12 to the carrier element 22 along edge clamping regions (e.g., spaced clamping regions) 26-1, 26-2 of the transducer element 12. That is, the transducer element 12 is anchored or attached along its edge clamping regions 26-1, 26-2 by the first clamping structures 24-1, 24-2. Therefore, the edge clamping regions 26-1, 26-2 refer to portions or areas defined along the edges (e.g., lateral edges) of the transducer element 12 and mechanically secured by the first clamping structures 24-1, ..., 24-#. These regions may be spatially separated from each other; that is, they may be spatially discontinuous. In other words, the edge clamping area of ​​the transducer element can be defined as a spaced / spatially separated area along the (lateral) boundary or (lateral) periphery of the transducer element 12, which is defined in a plane parallel to the main external surface of the transducer element 12 or the carrier element 22, as clearly seen in the top view of FIG1a.

[0032] As shown in the examples in Figures 1a-d, the MEMS device 10 includes two (laterally opposite) clamping or anchoring structures 24-1, 24-2 for mechanically connecting (anchoring) the transducer element 12 to the carrier element 22 along the spaced peripheral regions 26-1, 26-2 of the transducer element 12.

[0033] As illustrated in Figures 1a-d, the MEMS device 10 also includes an elongation structure 32 that extends laterally from the unclamped edge regions 34-1, 34-2 of the transducer element 12. In other words, the elongation structure 32 (laterally) protrudes from the unclamped edge regions 34-1, 34-2 of the transducer element 12. That is, the transducer element 12 is not anchored or attached along its unclamped edge regions 34-1, 34-2. Therefore, the unclamped edge regions 34-1, 34-2 refer to portions or areas defined along the edges (e.g., lateral edges) of the transducer element 12 that are not mechanically secured (i.e., where the first clamping structures 24-1, 24-2 are absent). These regions can be spatially separated from each other; that is, they can be spatially discontinuous. In other words, the unclamped edge region of the transducer element can be defined as a spaced / spatially separated portion / region along the (lateral) boundary or (lateral) perimeter of the transducer element 12, which is defined in a plane parallel to the main external surface of the transducer element 12 or the carrier element 22, as clearly visible in the top view of FIG1a.

[0034] For example, as shown in Figures 1a-d, the elongated structure 32 is arranged symmetrically with respect to the transducer element 12. More specifically, the elongated structure 32, including a (lateral) width w, is arranged over the unclamped edge regions 34-1 and 34-2 of the adjacent transducer element, that is, the elongated structure 32 (laterally) extends outward from the two unclamped edge regions 34-1 and 34-2 of the transducer element 12.

[0035] MEMS device 10 also includes a plurality of second clamping structures 36-1, 36-2 for mechanically connecting the elongated structure 32 to the carrier element at the edge clamping regions 38-1, 38-2 of the elongated structure 32. That is, the elongated structure 32 is anchored or attached along its edge clamping regions 38-1, 38-2 by the second clamping structures 36-1, 36-2. Therefore, the edge clamping regions 38-1, 38-2 refer to portions or areas defined along the edges (e.g., lateral edges) of the elongated structure 32 and mechanically secured by the second clamping structures 36-1, 36-2. These regions can be spatially separated from each other; that is, they can be spatially discontinuous. In other words, the edge clamping regions of the elongated structure can be defined as spaced / spatially separated regions along the (lateral) boundary or (lateral) perimeter of the elongated structure 32, defined in a plane parallel to the main external surface of the transducer element 12 or the carrier element 22, as clearly seen in the top view of FIG1a.

[0036] Therefore, according to the embodiment, the (sound) transducer element 12 of the MEMS device 10 is mechanically anchored (coupled) along at least two edge (clamping) regions (or lateral periphery / boundary regions) 26-1, 26-2 of the transducer element 12, and furthermore, the elongation structure 32 extends (or protrudes from) away from at least two unclamped edge regions (or unclamped lateral periphery / boundary regions) 34-1, 34-2 of the transducer element 12 (as opposed to a conventional SDM MEMS microphone that does not include the elongation structure). This configuration or arrangement of the MEMS device 10 improves the compliance of the membrane arrangement of the first deflectable membrane structure 14 and the second deflectable membrane structure 18 with mechanical coupling, and thus improves its mechanical sensitivity, and consequently improves the overall operating performance of the MEMS device.

[0037] As clearly shown in Figures 1b-d, the elongation structure 32 includes a first elongation element 40 extending from the transducer element 12 to the second clamping structures 36-1, 36-2, at least partially in the same plane as the first deflectable membrane structure 14. Specifically, Figures 1a-d show the elongation structure 32 including two laterally adjacent first elongation elements 40 of the transducer elements 12.

[0038] According to an embodiment, preferably, the elongation structure may include a first elongation element that extends from the transducer element to the second clamping structure entirely in the same plane as the first deflectable membrane structure.

[0039] As shown in Figures 1a-d, transducer element 12 is mechanically decoupled from carrier element 22 (unclamped or unattached) along and laterally between the unclamped edge regions (or the periphery regions of the unclamped gaps) 34-1, 34-2, and is therefore displaceable (deflectable) with respect to carrier element 22. Thus, according to the embodiment, transducer element 12 is mechanically decoupled from carrier element 22 at the unclamped edge regions 34-1, 34-2.

[0040] Furthermore, along and laterally between the (corresponding) second clamping structures 36-1, 36-2 and the (corresponding) unclamped edge regions (or unclamped interval periphery regions) 34-1, 34-2, the elongated structure 32 is mechanically decoupled from the carrier element 22 (unclamped or unattached), and is therefore also displaceable (deflectable) with respect to the carrier element 22.

[0041] More specifically, the deflectable portion 14-1 of the first deflectable membrane structure 14 and the deflectable portion 18-1 of the second deflectable membrane structure 18 of the transducer element 12 extend between the (laterally) opposite first clamping (anchoring) structures 24-1, 24-2 (at the spaced peripheral regions 26-1, 26-2) and are also mechanically decoupled from the carrier element 22, thus being displaceable (deflectable) with respect to the carrier element 22.

[0042] Furthermore, according to an embodiment, the first elongation element 40 of the elongation structure 32 can be formed as a lateral extension of the first deflectable membrane structure 14. This lateral extension can extend from the unclamped edge regions 34-1, 34-2 of the transducer element 12 toward the corresponding second clamping structures 36-1, 36-2, and can also be mechanically decoupled from the carrier element 22, and thus can be displaceable (deflectable) with respect to the carrier element 22.

[0043] As can be clearly seen from Figures 1a-d, the edge clamping regions 26-1 and 26-2 of the transducer element 12 and the edge clamping regions 38-1 and 38-2 of the elongation structure 32 are arranged in an alternating order. In other words, the edge clamping regions 38-1 and 38-2 of the elongation structure 32 are (laterally) located between the edge clamping regions 26-1 and 26-2 of the transducer element 12.

[0044] As clearly shown in Figures 1a-b, each of the plurality of second clamping structures 36-1, 36-2 includes a first portion extending (laterally) parallel to (e.g., or along) the edge clamping regions 26-1, 26-2 of the transducer element 12, and a second portion extending (laterally) parallel to the unclamped edge regions 34-1, 34-2 of the transducer element 12. The first and second portions together span the (lateral) outer periphery or boundary of the elongated structure 32.

[0045] As exemplarily shown in Figures 1a-d, the first clamping (anchoring) structures 24-1, 24-2 along the spacer perimeter regions 26-1, 26-2 and the (unclamped) spacer perimeter regions 27-1, 27-2 may include a straight orientation or shape to provide a rectangular shape for the transducer element 12. However, other shapes or orientations are also possible. For example, the first clamping (anchoring) structures 24-1, 24-2 along the spacer perimeter regions 26-1, 26-2 and the (unclamped) spacer perimeter regions 27-1, 27-2 may also include a curved (e.g., convex or concave) or straight orientation or shape in pairs (for symmetry reasons). For symmetry reasons, the first clamping structures 24-1, 24-2 may be equally spaced (equidistantly arranged) along the edge clamping regions (spacer perimeter regions) 26-1, 26-2. The edge clamping areas (interval clamping perimeter areas) 26-1, 26-2 and the unclamped edge areas (unclamped interval perimeter areas) 27-1, 27-2 can be equally spaced (equidistantly arranged) along the (lateral) perimeter or boundary of the transducer element 12.

[0046] Furthermore, as shown in Figures 1a-b, the second clamping (anchoring) structures 36-1, 36-2 along the edge clamping regions 38-1, 38-2 can have a straight orientation or shape, thereby providing a rectangular shape for the elongated structure 32. However, other shapes or orientations are also possible. For example, the first and / or second portions of the previously described second clamping (anchoring) structures 36-1, 36-2 along the edge clamping regions (or spaced peripheral regions) 38-1, 38-2 can also include curved (e.g., convex or concave) or straight orientations or shapes in pairs (for symmetry reasons). For symmetry reasons, the second clamping structures 36-1, 36-2 can be equally spaced (equidistantly arranged) along the edge clamping regions 38-1, 38-2.

[0047] According to this embodiment, compared with conventional SDM microphones of the same physical size (footprint or chip size), the MEMS device 10 with a half-bridge or (single-sided) cantilever SDM design (e.g., in the form of an SDM microphone) can achieve (at least) higher compliance (flexibility) with a mechanically coupled first deflectable membrane structure 14 and second deflectable membrane structure 18 and elongation structure 32 membrane arrangement.

[0048] As exemplarily shown in Figures 1a-b, the MEMS device 10 may have the following typical dimensions. The footprint (vertical projection) of the MEMS device 10 may have a first lateral dimension (= width along AA') between 0.5 and 2.0 mm and approximately 1.2 mm, and may have a second lateral dimension (= length along BB') between 0.5 and 2.0 mm and approximately 1.7 mm. The deflectable film structures 14, 18 may have a first lateral dimension (= width along AA') between 0.3 and 1.8 mm and approximately 0.7 mm. The rigid electrode 16 may have a first lateral dimension (= width along AA') between 0.3 and 1.8 mm and approximately 0.7 mm. The deflectable film structures 14, 18 may have a second lateral dimension (= length along BB') between 0.3 and 1.8 mm and approximately 1.2 mm. The rigid electrode 16 may have a second lateral dimension (= length along BB') between 0.3 and 1.8 mm and approximately 1.2 mm.

[0049] The deflectable film structures 14, 18 can be vertically spaced between 1 µm and 10.0 µm, and approximately 4.0 µm, and can have a thickness of approximately 0.2 to 1 µm; the rigid electrode can have a thickness of approximately 0.2 to 2 µm; and the vertical gap (spacing in the static (=undeflected) state) between the opposing layers (rigid electrode-deflectable film) can be approximately 0.5 to 5 µm. For example, the vertical spacing between the deflectable film structures 14, 18 can be less than at least 1 µm, or at least 2.5 µm, or at least 5 µm, or at least 7.5 µm, or at least 10 µm. In other words, the vertical spacing between the deflectable film structures 14, 18 can be adapted to be smaller than the size associated with particulate matter. For example, the vertical spacing between the deflectable film structures 14, 18 can be adapted to be smaller than the size associated with PM. 2.5 (2.5 µm) or PM 10 (10 µm) associated dimensions. Through this measure, such as PM... 2.5 and PM 10 Particulate matter may not accumulate between the deflectable membrane structures 14 and 18, thereby preventing the deflectable membrane structures 14 and 18 from clogging (or blocking).

[0050] The first lateral elongation or width w of the elongation structure 32 can range from 300 µm to 2000 µm. The second lateral elongation or length of the elongation structure 32 can also range from 300 µm to 2000 µm. For example, as shown in Figures 1a-b, the second lateral elongation or length of the elongation structure 32 can be the same as the second lateral dimension (= length along BB') of the transducer element 12.

[0051] The terms “electrode structure” and “film structure” are intended to describe that film structures and (multiple) rigid electrode structures may each comprise a semiconductor layer or a conductive layer, or may comprise a sequence or stack of layers having multiple different layers, wherein at least one of the layers is conductive, such as a (highly doped) conductive polycrystalline silicon layer or a metal layer.

[0052] According to embodiments, and as exemplarily shown in Figures 1a-c (and Figures 2a-b, 3a-b, and 4a-d further presented below), the (sound) transducer element 12 of the MEMS device 10 may have microphone and / or speaker functionality. Therefore, the MEMS device 10 can be implemented as a MEMS microphone or MEMS speaker, for example, a hermetically sealed dual-diaphragm (SDM) microphone or speaker with a half-bridge design.

[0053] Microphones are used to sense or detect ambient sound. Speakers are used to emit acoustic or ultrasonic sound into the environment. Therefore, the acoustic transducer element 10 can be configured as a sensor (e.g., a microphone or pressure sensor) or an actuator (e.g., a speaker).

[0054] When the acoustic transducer element 12 is implemented as a capacitive sensor, the deflection ±Δz of the membrane arrangement of the first deflectable diaphragm structure 14 and the second deflectable diaphragm structure 18 with mechanical coupling is based on the applied external pressure load. The deflection or displacement ±Δz of the deflectable diaphragm arrangement can then be detected and capacitively read out to provide a corresponding (analog or analog-to-digital) output signal for the acoustic transducer element 12. The deflection ±Δz of the deflectable diaphragm arrangement is (typically) caused by acoustically induced (sound) pressure changes in the environment.

[0055] According to another embodiment, the acoustic transducer element 12 can also be implemented as an actuator, for example, in the form of a loudspeaker (due to its operating mode), which uses the capacitance effect to generate sound. The initial mechanical movement of the deflectable diaphragm arrangement is generated by applying a (modulated) voltage between the first deflectable diaphragm structure 14 and the second deflectable diaphragm structure 18, wherein this movement is typically converted into audible or ultrasonic sound.

[0056] According to an embodiment, and as shown in Figures 1c-d, the carrier element 22 (e.g., a substrate or frame structure) may include a recess 46 (or, for example, an opening, a gap, or a cavity). The transducer element 12 and the extension structure 32 may be arranged (e.g., attached) to cover the recess 46 in the carrier element 22. As shown in Figures 1c-d, the deflectable portion 14-1 of the first deflectable film structure 18 may face the recess (or opening) 46 in the carrier element (substrate or frame structure) 22.

[0057] The groove (or opening) 46 in the carrier element 22 may have a shape or orientation that is substantially the same as, or slightly laterally offset (enlarged) to, the unclamped edge region (or unclamped spacer periphery region) 27-1, 27-2 of the transducer element 12 in vertical projection, to allow the deflection ±Δz of the membrane arrangement of the first deflectable membrane structure 14 and the second deflectable membrane structure 18 with mechanical coupling (to allow the deflection ±Δz of the deflectable portion 14-1 of the first deflectable membrane structure 14 and the deflectable portion 18-1 of the second deflectable membrane structure 18 and the elongated element of the elongation structure 32).

[0058] According to an embodiment, the rigid electrode structure 16 can be formed as a counter electrode (e.g., a perforated stator or backplate) with respect to the first deflectable film structure 14 and / or the second deflectable film structure 18.

[0059] Due to the half-bridge design of the MEMS device 10, the rigid electrode structure 16 can be mechanically clamped to the carrier element 22 at the edge clamping regions 26-1, 26-2 by means of the first clamping structures 24-1, 24-2, and mechanically decoupled from the carrier element 22 along the unclamped edge regions (or unclamped interval peripheral regions) 27-1, 27-2 (with respect to which it is deflectable). Since the film arrangements 14, 18 of the transducer element 12 (the first deflectable film structure 14 and the second deflectable film structure 18 with mechanical coupling) are arranged, for example, over the groove (or opening) 46 in the carrier element 22, the deflectable portions 14-1, 18-1 of the film arrangements 14, 18 of the transducer element 12 are mechanically decoupled from the carrier element 22 (unclamped), thus displaceable (deflectable) with respect to the carrier element 22. Furthermore, the elongated element of the elongation structure 32 is also mechanically decoupled from the carrier element 22, and therefore also displaceable (deflectable) with respect to the carrier element 22.

[0060] Each clamping structure 24-1, 24-2 may include a first isolation element 24-A between the peripheral portion of the top membrane 14 and the stator 16, and a second isolation element 24-B between the peripheral portion of the bottom membrane 18 and the stator 16, wherein the transducer element 12 is mechanically anchored to the carrier element 22 by means of a third isolation element 24-C of the clamping structures 24-1, ..., 24-#. Different isolation elements (e.g., oxide elements or layers) 24-A, 24-B, 24-C of the clamping structures 24-1, ..., 24-# are provided to mechanically secure the boundary regions of the membranes 14, 18 and the stator 16 with respect to the carrier element 22.

[0061] Furthermore, the transducer element 12 of the MEMS device 10 may include wall elements (support walls) 29-1, 29-2 in the unclamped edge regions (unclamped interval periphery regions) 34-1, 34-2, wherein the transducer element 12 is mechanically decoupled (unclamped) from the carrier element 22 along and laterally between the unclamped edge regions 34-1, 34-2, and is therefore displaceable (deflectable) with respect to the carrier element 22.

[0062] According to an embodiment, as shown in Figures 1c-d, the mechanical connection element 20 may include a plurality of pillar-like or columnar mechanical connection elements between two opposing deflectable membrane structures 14, 18.

[0063] Wall elements (support walls) 29-1 and 29-2 may comprise the same material as the mechanical connecting element (support or column) 20. Furthermore, wall elements (support walls) 29-1 and 29-2 may have the same (lateral) thickness and (vertical) height as the mechanical connecting element 20. Therefore, wall elements (support walls) 29-1 and 29-2 can be considered as line elements in vertical projection, while the mechanical connecting element can be considered as a point element in vertical projection.

[0064] According to an embodiment, and as exemplarily shown in FIG1b (and FIG2a-b further presented below), the MEMS device 10 also includes wall structures 44 at the unclamped edge regions 34-1, 34-2 of the transducer element 12. It should be noted that, according to the perspective view of FIG1b, only one of the wall structures 44 at the unclamped edge region 34-1 of the transducer element 12 may be visible, without excluding the presence of the other wall structure 44 at the unclamped edge region 34-2 of the transducer element 12. Furthermore, as shown in FIG1b, the wall structure 44 may be arranged to extend (vertically) across the starting portion of the elongation structure 32 (not shown in FIG1b, but indicated in FIG3a-d disclosed below) toward the second deflectable film structure 18. It will be understood that, in other embodiments, the wall structure 44 may extend toward the first deflectable film structure, wherein the elongation structure is at least partially in the same plane as the second deflectable film structure. In another embodiment, the elongation structure 32 may include a first elongation element 40 and a second elongation element 42 that extend at least partially in the same plane as the first deflectable membrane structure 14 and the second deflectable membrane structure 18, respectively, and the wall structure 44 may extend / cross from a first starting portion of the first elongation element to a second starting portion of the second elongation element, and vice versa.

[0065] The dimensions of the wall structure 44 (at the unclamped edge regions 34-1, 34-2 of the transducer element 12) can be adapted to prevent contaminants (or pollutants such as particulate matter, e.g., PM) from entering the system. 2.5 PM 10The accumulation caused by the passage or continuous passage of particulate matter. For example, the vertical spacing (or vertical height) of the wall elements 44 can be adapted to be the same as the vertical spacing between the two deflectable membrane structures 14, 18. For example, the vertical spacing (or vertical height) of the wall elements 44 can be less than at least 1 µm, or at least 2.5 µm, or at least 5 µm, or at least 7.5 µm, or at least 10 µm. By doing so, the MEMS device 10 can prevent the passage or accumulation of particulate matter and allows the MEMS device 10 to be less prone to (or less susceptible to, or more robust to) the deterioration of its operating characteristics. This can further allow for increased durability of the MEMS device 10.

[0066] Furthermore, according to an embodiment, the wall structure 44 (together with the first clamping structures 24-1, 24-2) and the first deflectable membrane structure 14 and the second deflectable membrane structure 18 can together form a cavity 48 relative to the environment 50. This cavity 48 can be sealed relative to the environment 50.

[0067] As exemplarily depicted by the dashed curved portion, the wall structure 44 may optionally include a single corrugated wall segment 45, wherein, as shown in the oblique view of FIG1b, the corrugated wall segment 45 has a curved, circular, sinusoidal, or semi-circular shape that extends (laterally) into the cavity 48, i.e., the corrugated wall segment 45 may be bent inward or bent into the cavity 48. Alternatively, the corrugated wall segment 45 may extend (laterally) outward or away from the cavity 48, i.e., the corrugated wall segment 45 may bulge or project outward or away from the cavity 48 (e.g., in a straight or curved manner). Thus, the corrugated wall segment 45 can form a lateral extension of the wall structure 44.

[0068] For example, the corrugated wall segment 45 may have a circular, elliptical, or elliptical cross-sectional shape in a vertical projection. Alternatively, the corrugated wall segment 45 may have a straight, square, rectangular, triangular, or sawtooth shape. Furthermore, the wall structure 44 may include multiple corrugated wall segments 45-#. For example, the multiple corrugated wall segments 45-# may be laterally spaced from each other along the unclamped edge regions 34-1, 34-2 of the transducer element 12 by means of an intermediate wall structure (spacer).

[0069] According to one embodiment, the plurality of corrugated wall segments 45-# may include corrugated wall segments extending (e.g., bending) or extending (e.g., bending) into the cavity 48 (laterally). According to another embodiment, the plurality of corrugated wall segments 45-# may extend (e.g., bending) or extend away from the cavity 48 (e.g., bending) (laterally). According to yet another embodiment, the plurality of corrugated wall segments 45-# may include a first group of corrugated wall segments 45-# and a second group of corrugated wall segments 45-#, wherein the first group of corrugated wall segments 45-# may extend (e.g., bending) or extend (e.g., bending) into the cavity 48 (laterally), and the second group of corrugated wall segments 45-# may extend (e.g., bending) or extend away from the cavity 48 (laterally). For example, the first group of corrugated wall segments 45-# and the second group of corrugated wall segments 45-# may together form an extension including an "S"-shaped wall structure 44.

[0070] The above-mentioned configuration of the wall structure 44, including the corrugated wall section 45, can improve the compliance of the transducer element 12, thereby helping to improve the overall operating performance of the MEMS device 10.

[0071] According to an embodiment, the sealed cavity 48 may include a low-pressure region. This low-pressure region is located within the sealed cavity 48 and may include reduced atmospheric pressure compared to the ambient atmosphere; for example, the reduced atmospheric pressure in the low-pressure region may be a vacuum or near-vacuum.

[0072] The low-pressure region may have an atmospheric pressure that is lower than ambient pressure or standard atmospheric pressure. More specifically, according to embodiments, the pressure in the low-pressure region may be essentially a vacuum or near a vacuum. Alternatively, the pressure in the low-pressure region may be approximately 50% (or 40%, 25%, 10%, or 1%) below ambient pressure or standard atmospheric pressure. Standard atmospheric pressure is typically 101.325 kPa or 1013.25 mbar. The pressure in the low-pressure region may also be expressed as absolute pressure, for example, below 50, 40, 30, or below 10 kPa.

[0073] As exemplarily shown in Figures 1a-c (and Figures 2a-b presented subsequently), the transducer element 12 of the MEMS device 10 may have straight (e.g., slightly curved; or slightly recessed or slightly convex) wall elements (support walls) 29-1, 29-2.

[0074] Figures 2a-b below present two further embodiments of exemplary arrangements of the elongated structure 32 and the transducer element 12. The embodiment shown in Figure 2a provides an alternative to the embodiments described in Figures 1b-d, while the embodiment in Figure 2b can be obtained / implemented by combining the former with the latter.

[0075] Figure 2a exemplarily illustrates a schematic cross-sectional view (parallel to the xz plane) of an exemplary MEMS device 10 along section line AA' (= cross-sectional plane 1). According to an embodiment, and as shown in Figure 2a, the elongation structure 32 includes a second elongation element 42 that extends at least partially from the transducer element 12 into the second clamping structures 36-1, 36-2 in the same plane as the second deflectable film structure 18. According to an embodiment, for example, the second elongation element 42 may extend entirely from the transducer element 12 into the second clamping structures 36-1, 36-2 in the same plane as the second deflectable film structure 18.

[0076] It should be emphasized that, in the embodiments shown in Figures 1a-d, where the (first) elongating element 40 of the elongating structure 32 extends at least partially or completely in the same plane as the first deflectable membrane structure 14, and in the embodiment shown in Figure 2a, where the (second) elongating element 42 of the elongating structure 32 extends at least partially or completely in the same plane as the second deflectable membrane structure 18, two possible arrangements of the elongating structure 32 and the deflectable membrane structures 14 and 18 of the transducer element 12 are disclosed according to the present invention (both are equally preferred).

[0077] Figure 2b exemplarily illustrates a schematic cross-sectional view (parallel to the xz plane) of another exemplary MEMS device 10 according to an embodiment along section line AA' (= cross-sectional plane 1). As shown in Figure 2b, according to an embodiment, the elongation structure 32 may include a first elongation element 40 and a second elongation element 42, wherein the first elongation element 40 extends at least partially or possibly entirely from the transducer element 12 to the second clamping structures 38-1, 38-2 (at the edge clamping regions 38-1, 38-2) in the same plane as the first deflectable structure 14, and the second elongation element 42 extends at least partially or possibly entirely from the transducer element 12 to the second clamping structures 38-3, 38-4 (at the edge clamping regions 38-3, 38-4) in the same plane as the second deflectable film structure 18.

[0078] Furthermore, according to the embodiments and Figures 2a-b, the second elongation element 42 of the elongation structure 32 can be formed as a lateral extension of the second deflectable membrane structure 18. These lateral extensions can extend from the unclamped edge regions 34-1, 34-2 of the transducer element 12 toward the corresponding second clamping structure 36-#, and can also be mechanically decoupled from the carrier element 22, thus allowing displacement (deflection) with respect to the carrier element 22.

[0079] In the following, Figures 3a-d present two further embodiments of an exemplary implementation of the elongation structure 32 to the transducer element 12, wherein the elongation structure 32 includes stress relief structures, such as corrugated elements or slits / through holes.

[0080] Figure 3a exemplarily illustrates a schematic cross-sectional view (parallel to the xz plane) of an exemplary MEMS device 10 along section line AA' (= cross-sectional plane 1). The MEMS device 10 depicted in Figure 3a can be considered a variant of the exemplary MEMS device 10 shown in Figure 1c. Specifically, according to the embodiment and Figure 3a, the elongation structure 32 includes a corrugated element 54 (e.g., as a stress-relieving structure), wherein the corrugated element 54 (lateral) extends parallel to the second clamping structures 36-1, 36-2.

[0081] Figure 3b exemplarily illustrates a partial oblique cross-sectional view (oblique relative to the xy plane) of the exemplary MEMS device 10. In contrast to Figure 3a, the elongation structure 32 includes a single corrugated element 54 extending (laterally) parallel to the second clamping structure 36-1.

[0082] According to the embodiment and Figures 3a and 3b, the starting portion 33 and the ending portion 35 of the elongated structure 32 are depicted in the same plane as the first deflectable membrane structure 14. Alternatively or additionally, the starting portion 33 and the ending portion 35 of the elongated structure 32 may be in the same plane as the second deflectable membrane structure 18.

[0083] The oblique view shown in Figure 3b and the cross-sectional view in Figure 3a clearly indicate that the (multiple) corrugated elements 54 may extend (vertically) in a direction into the cavity 46 and / or in a direction away from the cavity 46. Furthermore, the (multiple) corrugated elements 54 may include curved, circular, sinusoidal, or semi-circular shapes.

[0084] Figure 3c illustrates a schematic cross-sectional view (parallel to the xy plane) of an exemplary MEMS device 10 along section line AA'. As clearly shown in Figure 3c, the elongated structure 32 includes a slit or through-hole 58.

[0085] Figure 3d exemplarily presents an oblique cross-sectional view (tilted relative to the xy plane) of an exemplary MEMS device 10. As clearly shown in Figure 3d, the elongated structure 32 includes a plurality of slits or through-holes 58-1, 58-2, 58-3. As shown in Figure 3d, the slits / through-holes 58-1, 58-2, 58-3 may be arranged parallel to the wall structure 44 of the transducer element 12 at the unclamped edge region 34-1. For example, the size (lateral extension range) of the slits or through-holes may be adapted to prevent particulate clogging; in other words, the slits or through-holes may be too small to allow contaminants (such as particulate matter) to pass through.

[0086] The slit or via 58-# allows lateral air exchange to balance slow (static, e.g., temperature-dependent) environmental pressure changes between the substrate / carrier element 22 and the elongated structure 32 of the acoustic transducer element 12 (as a low-pass function). Furthermore, the slit or via 58-# can include not only the straight orientation or shape shown in Figures 3c-d, but also curved orientations or shapes.

[0087] To date, this disclosure provides (multiple) schematic cross-sectional views (parallel to the xy plane) of different MEMS devices 10 along section line AA' (= cross-sectional plane 1) in Figures 2a and 3a-d. These (multiple) cross-sectional views are accompanied by corresponding schematic cross-sectional views (parallel to the yz plane) of the corresponding exemplary MEMS device 10 along section line BB' (= cross-sectional plane 2), as depicted in Figure 1d.

[0088] In the following, with reference also to Figures 1a-d, 2a-b, and 3a-d, different embodiments of a MEMS device 10 implemented as a MEMS microphone or MEMS speaker (e.g., a hermetically sealed dual-diaphragm (SDM) microphone or speaker with a half-bridge design) are described. The half-bridge design of the described MEMS device 10 (due to the elongation structure 32) improves the compliance of the membrane structure with mechanical coupling of the first deflectable membrane structure 14 and the second deflectable membrane structure 18, and thus improves its mechanical sensitivity, and consequently improves the overall operational performance of the MEMS device in the form of a MEMS microphone or MEMS speaker (e.g., a hermetically sealed dual-diaphragm (SDM) microphone or speaker).

[0089] Figures 4a-d show schematic top (plan) views of a MEMS device 10 according to another embodiment of the present disclosure, wherein the half-bridge or (multiple) half-cantilever design of the MEMS device 10 has another exemplary implementation, such as in the form of an SDM acoustic transducer (microphone or speaker).

[0090] As exemplarily shown in FIG4a, the (sound) transducer element 12 having a membrane arrangement of a first deflectable membrane structure 14 and a second deflectable membrane structure 18 with mechanical coupling may include a rectangular shape (in the transverse plane).

[0091] The first clamping (anchoring) structures 24-1, 24-2 along the edge clamping regions (or spaced clamping / peripheral regions) 26-1, 26-2 and the elongated structures 32 extending along the unclamped edge regions (or unclamped spaced peripheral regions) 34-1, 34-2 may include a straight orientation or shape, such that the footprint (substrate area) of the (acoustic) transducer element 12 is rectangular (lateral) (see solid lines in FIG. 4a). However, the first clamping (anchoring) structures 24-1, 24-2 along the edge clamping regions 26-1, 26-2 and the elongated structures 32 along the unclamped edge regions 34-1, 34-2 may also (for symmetry reasons) include convex, concave, or straight orientations or shapes in pairs (see also dashed lines in FIG. 4a, which indicate the possible shapes of the first clamping structures).

[0092] Therefore, the MEMS device 10 of Figure 4a includes a half-bridge design, which can also be viewed as a “dual-arm” configuration, in which two arms extend from the geometric center region (or center point) 28 of the transducer element 12.

[0093] Therefore, as exemplarily shown in FIG4a, the MEMS device 10 may include a transducer element 12, which may have a polygonal shape having an even number of sides or edges. The shape of the transducer element 12 may also be a simple convex polygon. As exemplarily shown in FIG4a, the transducer element 12 may be clamped or mechanically anchored to a carrier element (or substrate) 22 along two opposite sides or edges 26-1, 26-2, and the elongation structure 32 may extend away along two opposite sides or edges 34-1, 34-2, and be clamped or mechanically connected (or anchored) to the carrier element (or substrate) 22.

[0094] As exemplarily shown in Figures 4b-d, the (sound) transducer element 12, which has a membrane arrangement of a first deflectable membrane structure 14 and a second deflectable membrane structure 18 with mechanical coupling, may include a multi-arm configuration together with the elongation structure 32.

[0095] Figure 4b illustrates an exemplary three-arm configuration in which the transducer element 12 can be clamped or mechanically anchored to the carrier element (or substrate) 22 along three edges / sides by three first clamping (or anchoring) structures 24-1, 24-2, 24-3 along spaced peripheral regions 26-1, 26-2, 26-3, and the elongated structure 32 extending away from the unclamped edge regions 34-1, 34-2, 34-3 can be clamped or mechanically connected (or anchored) to the carrier element (or substrate) 22 by second clamping structures 36-1, 36-2, 36-3.

[0096] The exemplary configuration of Figure 4b is also applicable to any odd number of arms, i.e., 2N+1, where N = 1, 2, 3, 4, ..., wherein the first clamping (anchoring) structures 24-1, ..., 24-# (here: # = 2N+1) along the edge clamping regions (or spaced peripheral regions) 26-1, ..., 26-# may also (e.g., all regions for symmetry reasons) include a convex, concave, or straight orientation or shape, and wherein the second clamping (anchoring) structures 36-1, ..., 36-# (here: # = 2N+1) along the elongated structure 32 extending away from the unclamped edge regions (or unclamped spaced peripheral regions) 34-1, ..., 34-# (# = 2N+1) may also (e.g., at least in pairs or all regions for symmetry reasons) include a convex, concave, or straight orientation or shape.

[0097] Figure 4c illustrates an exemplary four-arm configuration in which the transducer element 12 can be clamped or mechanically anchored to the carrier element (or substrate) 22 along the four sides by four clamping or anchoring structures 24-1, 24-2, 24-3, 24-4 along the spaced peripheral regions 26-1, 26-2, 26-3, 26-4, and the elongated structure 32 extending away from the unclamped edge regions 34-1, 34-2, 34-3, 34-4 can be clamped or mechanically connected (or anchored) to the carrier element (or substrate) 22 by the second clamping structures 36-1, 36-2, 36-3, 36-4.

[0098] The exemplary configuration of Figure 4c is also applicable to any even number of arms, i.e., 2N, where N = 2, 3, 4, ..., wherein the first clamping (or anchoring) structures 24-1, ..., 24-# (here: # = 2N) along the edge clamping areas (or spaced peripheral areas) 26-1, ..., 26-#, and the second clamping (or anchoring) structures 36-1, ..., 36-# (# = 2N) along the elongated structures 32 extending away from the unclamped edge areas (or unclamped spaced peripheral areas) 34-1, ..., 34-# (# = 2N), may also (e.g., at least in pairs or for symmetry reasons) include convex, concave, or straight orientations or shapes.

[0099] Figure 4d exemplarily illustrates a circular (e.g., circular, elliptical, or oval) configuration of a (sound) transducer element 12, wherein the transducer element 12 may be clamped or mechanically anchored to a carrier element (or substrate) 22 along a plurality of (e.g., at least four) first peripheral segments by first clamping (or anchoring) structures 24-1, ..., 24-# along (e.g., at least four) edge clamping regions (or spaced peripheral regions) 26-1, ..., 26-#, and wherein an elongated structure 32 extending away from the unclamped edge regions 34-1, ..., 34-# may be clamped or mechanically coupled (or anchored) to the carrier element (or substrate) 22 along a plurality of (e.g., at least four) second peripheral segments by second clamping (or anchoring) structures 36-1, ..., 36-#.

[0100] Figures 4a-d also exemplarily illustrate, using dashed lines associated with the elongated structure 32, that the elongated structure 32 may include different orientations or shapes (or, for example, floor space). For example, the elongated structure 32 may include straight or curved (e.g., convex or concave) shapes. Furthermore, the elongated structure 32 may partially comprise a straight orientation or shape and may partially comprise a curved orientation or shape (e.g., concave or convex). These different orientations or shapes may be selected as desired or adapted according to preference. Additionally or alternatively, these different orientations or shapes may be the result of associated manufacturing processes or manufacturing steps (or, for example, due to some effect). Therefore, embodiments may include asymmetrical orientations or shapes of the elongated structure 32, which may be due to desired selection (or preference) and / or may be the result of associated manufacturing processes or manufacturing steps (or artificial traces).

[0101] The elongation structure 32 is depicted in Figures 4a-d as including a first elongation element 40 and / or a second elongation element 42 (specifically indicated by reference numerals 40 / 42 in Figures 4a-d). This means that each of Figures 4a-d involves at least three different configurations (with no particular preference) – the first is where the elongation structure 32 may include only the first elongation element 40, the second is where the elongation structure 32 may include only the second elongation element 42, and the third is where the elongation structure 32 may include both elongation elements 40 and 42.

[0102] The transducer element 12 may include a variety of shapes, and the list of shapes of the transducer element 12 exemplarily shown in Figures 1a, 3d and 4a-d should not be considered exhaustive. The additional geometric and structural implementations and configurations of the MEMS device 10 described below may also help improve the compliance of the film arrangement of the (acoustic) transducer element 12 with mechanically coupled first deflectable film structure 14 and second deflectable film structure 18.

[0103] According to an embodiment, as exemplarily shown in Figures 1a, 1b, 3d, and 4a-d, the overall combined length of the first clamping structures 24-1, ..., 24-# along the periphery of the transducer element 12 (e.g., a boundary, or a lateral periphery / boundary; e.g., a periphery in a plane parallel to the main surface region of the carrier element / substrate 22) (e.g., meaning that the lengths of each clamping structure 24-# are combined to form an overall combined length) can be equal to or less than (≤) 50% of the (overall) periphery length L (or overall boundary length) of the transducer element 12. Furthermore, for each edge clamping region (or spaced clamping region / spaced periphery region) 26-1, ..., 24-#, a lateral bisector 30 bisecting the corresponding edge clamping region 26-# can pass through the geometric center region (or point) (or lateral geometric center region / point) 28 of the transducer element. The number (i.e., count) of lateral bisectors 30 bisecting the corresponding edge clamping region 26-# may depend on the shape or symmetry of the transducer element 12 (e.g., the number of "arms"). For example, as shown in Figure 4b, a transducer element 12 with an odd number of "arms" can have an odd number of lateral bisectors 30 that bisect the edge clamping regions 26-1, ..., 26-N (N=3 in Figure 4b), and as shown in Figure 4a, a transducer element 12 with an even number of "arms" can have an even number of lateral bisectors 30 that bisect the edge clamping regions 26-1, ..., 26-N (N=2 in Figure 4a, N=4 in Figure 4c). Furthermore, for example, each lateral bisector 30 can also (laterally) bisect the transducer element 12, as shown in Figures 4a-d.

[0104] Furthermore, according to the embodiments, as exemplarily shown in Figures 1a, 1b, 3a, 3d and 4a-d, the overall combined length of the second clamping structures 36-1, ..., 36-# along the periphery of the elongated structure 32 (e.g., the boundary, or the lateral periphery / boundary; e.g., the periphery in a plane parallel to the main surface region of the carrier element / substrate 22) (e.g., meaning that the length of each clamping structure 36-# is combined to form the overall combined length) can be equal to or less than (≤) 50% of the (overall) periphery length L (or overall boundary length) of the transducer element 12.

[0105] According to an embodiment, the (lateral) geometric center region 28 may have a lateral extension around the (lateral) geometric center point "C" of the transducer element 12, which may be less than 1%, 3% or 5% of the overall first lateral extension (or lateral diameter) "D" of the transducer element 12.

[0106] According to an embodiment, as exemplarily shown in Figures 1a-c and 4a-d, the edge clamping regions 26-1, ..., 26-# can be equally spaced (equidistantly arranged) along the (lateral) periphery of the transducer element 12. Unclamped edge regions (or unclamped spaced periphery regions) 27-1, ..., 27-# are arranged along the (lateral) periphery of the transducer element 12 between the relatively spaced edge clamping regions 26-1, ..., 26-#.

[0107] According to the embodiment, as exemplarily shown in Figures 1a-c and 4a, 4c, and 4d, a plurality of first clamping structures 24-1, ..., 24-# may include 2N first clamping structures, where N = 1, 2, 3, 4, ..., wherein the corresponding lateral bisector 30 passes through two opposite edge clamping regions (spaced peripheral regions) 26-1, 26-2, ..., 26-# and the geometric center region 28 of the transducer element 12.

[0108] According to an embodiment, as exemplarily shown in FIG4b, a plurality of first clamping structures 24-1, ..., 24-# may include 2N+1 first clamping structures, where N=1, 2, 3, 4, ..., wherein each lateral bisector (or equivalent lateral axis of symmetry) of the transducer element 12 passes through the first clamping structures 24-1, ..., 24-# and the geometric center region 28 of the transducer element 12.

[0109] According to embodiments, as shown in Figures 1c-d, 2a-b, 3a, and 3c, the plurality of (pillar-shaped or columnar) mechanical connecting elements 20 may be non-conductive, for example, to enable the first membrane structure 14 and the second membrane structure 18 to function as two electrically isolated electrodes for differential (readout) operations, i.e., to allow differential readout configuration of the first membrane structure 14 and the second membrane structure 18. Therefore, the pillar may be at least partially made of an insulating material, wherein the pillar 20 may be made of an insulating material, such as silicon nitride, silicon oxide, polymers, or combinations thereof, or combinations thereof with a conductive layer (e.g., silicon), provided that the conductive portion of the pillar is separated from the membrane structures 14 and 18 by the insulating material.

[0110] According to another embodiment, the plurality of (pillar-shaped or columnar) mechanical connection elements 20 may be conductive, for example, to realize the electrical connection of the first membrane structure 14 and the second membrane structure 18 as two electrical connection electrodes.

[0111] In summary, the (sealed) dual- or multi-membrane MEMS microphone 10 with (vacuum) cavity 48 relies on multiple mechanical connecting elements (also called pillars or columns) 20 that connect the two membrane structures 14, 18 (in the case of a dual-membrane arrangement) and prevent the membrane structures 14, 18 from collapsing due to pressure loads on the two membrane structures 14, 18 (i.e., external pressure to the top membrane structure 14 and upward pressure to the bottom surface of the bottom membrane structure 18).

[0112] The mechanical connection element 20 of the dual-membrane MEMS microphone 10 is also applicable to the multi-membrane MEMS microphone 10 having three or more membrane structures, wherein adjacent membrane structures are mechanically coupled by means of the mechanical connection element 20. In this case, the MEMS device 10 is formed as a multi-membrane MEMS microphone with three membrane structures, and the MEMS device 10 may include a first rigid electrode structure, a second rigid electrode structure, and a first to a third deflectable membrane structure, which are arranged in a vertically spaced configuration (e.g., a vertically separated and spaced configuration). The first rigid electrode structure is sandwiched between the first and second deflectable membrane structures, wherein the second rigid electrode structure is sandwiched between the second and third deflectable membrane structures. Each of the first, second, and third deflectable membrane structures includes a deflectable portion, wherein the deflectable portions of the first, second, and third deflectable membrane structures are mechanically coupled to each other by means of the mechanical connection element 20 and mechanically decoupled from the first and second rigid electrode structures. This setup of MEMS device 10 can also be applied to multi-membrane MEMS microphones with four or more membrane structures.

[0113] As exemplarily shown in Figures 1a-d, 2a-b, 3a-d, and 4a-d, the transducer elements are depicted in their resting positions, for example, when no sound waves reach the deflectable membrane structures. Incident sound waves may cause the deflectable portions of membrane structures 14-1 and 18-1 to deflect. Furthermore, the two deflectable membrane structures 14-1 and 18-1 may be exposed to ambient pressure and potential sound pressure. The top side of the first deflectable membrane structure 14-1 can also be considered as the primary sound-receiving surface of the MEMS device 10. Additionally, the bottom side of the second deflectable membrane structure 18 can also be considered as the primary sound-receiving surface of the MEMS device 10. When sound waves are incident on membrane structures 14 and 18, the membrane structures 14 and 18 may deflect or oscillate. Displacement of one membrane (either of the two membrane structures 14-1 and 18-1) may cause a corresponding displacement of the second membrane, and vice versa. It should be noted that, according to several embodiments, membrane structures 14-1 and 18-1 may deflect in response to pressure changes caused by incident sound waves. An electrical signal may be generated by the deflection of membrane structures 14-1 and 18-1 and may be read out by multiple readout circuits. The readout circuits can process this electrical signal and may ultimately convert it into usable information, which may be the final step in signal processing.

[0114] Figures 4a-d illustrate different exemplary schematic top (plan) views of the MEMS device 10, and some implementations that may be used to improve mechanical compliance or mechanical sensitivity. The shapes of the transducer element 12 and the extension structure 32 can be selected or optimized for various objectives and combinations thereof, such as chip size, capacitance, motor sensitivity, resonant frequency, etc. In particular, the shape and design of the transducer element 12 and the extension structure 32 can even be optimized to achieve mechanical compliance requirements. Therefore, the transducer element 12 and the extension structure 32 can include a variety of shapes, and the list of shapes of the transducer element 12 and the extension structure 32 should not be considered exhaustive.

[0115] Furthermore, Figures 4a-d illustrate that a plurality of first clamping or mechanical anchoring structures 24-1, 24-2…24-# spaced along the edge clamping / peripheral regions (clamping regions) 26-1, 26-2, …, 26-# of the transducer element 12 can be supported by means of a carrier element (or substrate) 22. The number of such regions to which the transducer element 12 can be clamped to the substrate 22 can be at least two or more. According to another embodiment, the lateral bisector 30 bisecting the spaced peripheral regions (clamping regions) 26-1, 26-2…26-# can coincide with the (lateral) axis of symmetry (or axial line) of the transducer element 12.

[0116] Figures 4a-d also illustrate that a plurality of second clamping or mechanical anchoring structures 36-1, 36-2...36-# spaced along the edge clamping / peripheral regions (clamping regions) 38-1, 38-2, ..., 38-# of the elongated structure 32 can be supported by means of a carrier element (or substrate) 22. The number of such regions to which the elongated structure 32 can be clamped to the substrate 22 can be at least two or more.

[0117] Additional embodiments and aspects are described, which can be used alone or in combination with the features and functions described herein.

[0118] According to an embodiment, a MEMS device includes: a transducer element having a first deflectable film structure, a rigid electrode structure, and a second deflectable film structure arranged vertically at intervals, wherein the rigid electrode structure is disposed between the first and second deflectable film structures, each of the first and second deflectable film structures includes a deflectable portion, and wherein the deflectable portions of the first and second deflectable film structures are mechanically coupled to each other by means of mechanical connecting elements and mechanically decoupled from the rigid electrode structure; a carrier element for supporting the transducer element; and a plurality of first clamping structures for holding the transducer element... The transducer element is mechanically connected to the carrier element at the edge clamping region of the component; an elongation structure extends laterally from the unclamped edge region of the transducer element; a plurality of second clamping structures are used to mechanically connect the elongation structure to the carrier element at the edge clamping region of the elongation structure; and wherein the elongation structure includes a first elongation element that extends at least partially from the transducer element to the second clamping structure in the same plane as the first deflectable film structure, or wherein the elongation structure includes a second elongation element that extends at least partially from the transducer element to the second clamping structure in the same plane as the second deflectable film structure.

[0119] According to an embodiment, the elongation structure includes a first elongation element that extends at least partially from a transducer element to a second clamping structure in the same plane as the first deflectable membrane structure, and the elongation structure includes a second elongation element that extends at least partially from a transducer element to a second clamping structure in the same plane as the second deflectable membrane structure.

[0120] According to an embodiment, the starting and ending portions of the elongated structure are in the same plane as the first deflectable membrane structure, and / or the starting and ending portions of the elongated structure are in the same plane as the second deflectable membrane structure.

[0121] According to an embodiment, the transducer element is mechanically decoupled from the carrier element at the unclamped edge region.

[0122] According to an embodiment, the elongated structure includes a corrugated element extending parallel to the second clamping structure.

[0123] According to an embodiment, the elongated structure includes a slit or a through-hole.

[0124] According to an embodiment, the first elongated element is formed as a lateral extension of the first deflectable film structure, and

[0125] According to an embodiment, the second elongated element is formed as a lateral extension of the second deflectable membrane structure.

[0126] According to an embodiment, the edge clamping regions of the transducer element and the edge clamping regions of the elongation structure are arranged in an alternating sequence.

[0127] According to an embodiment, the carrier element includes a groove, and the transducer element and the elongation structure are arranged to cover the groove in the carrier element.

[0128] According to an embodiment, the MEMS device also includes a wall structure at the unclamped edge region of the transducer element.

[0129] According to an embodiment, the first deflectable membrane structure and the second deflectable membrane structure together with the wall structure form a cavity relative to the environment, wherein the cavity is sealed relative to the environment, and the cavity includes a low-pressure region, wherein the low-pressure region includes reduced atmospheric pressure compared to the ambient atmosphere.

[0130] According to an embodiment, the mechanical connecting element includes a plurality of pillar-like or columnar mechanical connecting elements between two opposing deflectable membrane structures.

[0131] According to an embodiment, the rigid electrode structure forms a counter electrode with respect to the first deflectable film structure and / or the second deflectable film structure.

[0132] According to an embodiment, the transducer element has microphone and / or speaker functionality.

[0133] Although some aspects have already been described as features within the context of the device, it is clear that such a description can also be regarded as a description of the corresponding features of the method.

[0134] Depending on the specific implementation requirements, embodiments of the control circuit may be implemented in hardware or software, or at least partially in hardware or at least partially in software. Typically, embodiments of the control circuit may be implemented as a computer program product having program code that, when run on a computer, performs one of the methods. The program code may, for example, be stored on a machine-readable medium.

[0135] As can be seen in the above detailed description, various features have been grouped in examples for the purpose of simplifying this disclosure. This method of disclosure should not be construed as reflecting an intention that the claimed examples require more features than are expressly recited in each claim. Rather, as reflected in the following claims, the subject matter may be present in fewer than all features of a single disclosed example. Therefore, the following claims are incorporated herein by reference, whereby each claim may stand alone as a separate example. While each claim may stand alone as a separate example, it should be noted that although a dependent claim may refer in the claims to a particular combination with one or more other claims, other examples may also include combinations of the subject matter of that dependent claim with each of the other dependent claims, or combinations of each feature with other dependent or independent claims. Such combinations are presented herein unless otherwise stated not to be intended. Furthermore, even if a claim is not directly dependent on an independent claim, it is intended to include the features of that claim in any other independent claim.

[0136] Although specific embodiments have been illustrated and described herein, those skilled in the art will understand that various alternatives and / or equivalent implementations can be used to replace the illustrated and described specific embodiments without departing from the scope of these embodiments. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that the embodiments be limited only to the claims and their equivalents.

Claims

1. A MEMS device (10), comprising: The transducer element (12) has a first deflectable film structure (14), a rigid electrode structure (16), and a second deflectable film structure (18) arranged vertically at intervals. The rigid electrode structure (16) is arranged between the first deflectable film structure (14) and the second deflectable film structure (18), the first deflectable film structure (14) and the second deflectable film structure (18) each including a deflectable portion (14-1, 18-1), wherein the deflectable portion (14-1) of the first deflectable film structure (14) and the deflectable portion (18-1) of the second deflectable structure (18) are mechanically coupled to each other by means of a mechanical connecting element (20) and mechanically decoupled from the rigid electrode structure (16); Carrier element (22) is used to support the transducer element (12); Multiple first clamping structures (24-1, ..., 24-#) are used to mechanically connect the transducer element (12) to the carrier element (22) at the edge clamping regions (26-1, ..., 26-#) of the transducer element (12); The elongated structure (32) extends laterally from the unclamped edge region (34-1, ..., 34-#) of the transducer element (12); Multiple second clamping structures (36-1, ..., 36-#) are used to mechanically connect the elongated structure (30) to the carrier element (22) at the edge clamping regions (38-1, ..., 38-#) of the elongated structure (32); and The elongation structure (32) includes a first elongation element (40) that extends at least partially from the transducer element (12) to the second clamping structure (36-1, ..., 36-#) in the same plane as the first deflectable membrane structure (14). or The elongation structure (32) includes a second elongation element (42) that extends at least partially from the transducer element (12) to the second clamping structure (36-1, ..., 36-#) in the same plane as the second deflectable membrane structure (18).

2. The MEMS device (10) according to claim 1, wherein the elongation structure (32) includes a first elongation element (40) that extends at least partially from the transducer element (12) to the second clamping structure (24-1, ..., 24-#) in the same plane as the first deflectable film structure (14). and The elongation structure (32) includes a second elongation element (42) that extends at least partially from the transducer element (12) to the second clamping structure (36-1, ..., 36-#) in the same plane as the second deflectable membrane structure (18).

3. The MEMS device (10) according to claim 1 or 2, wherein the starting portion (33) and the ending portion (35) of the elongated structure (32) are in the same plane as the first deflectable film structure (14), and / or The starting portion (33) and the ending portion (35) of the elongated structure (32) are in the same plane as the second deflectable membrane structure (18).

4. The MEMS device (10) according to any one of claims 1 to 3, wherein the transducer element (12) is mechanically decoupled from the carrier element (22) at the unclamped edge region (34-1, ..., 34-#).

5. The MEMS device (10) according to any one of claims 1 to 4, wherein the elongation structure (32) includes a corrugated element (54) extending parallel to the second clamping structure (36-1, ..., 36-#).

6. The MEMS device (10) according to any one of claims 1 to 5, wherein the elongated structure (32) comprises a slit or a through hole (58).

7. The MEMS device (10) according to any one of claims 1 to 6, wherein the first elongation element (40) is formed as a lateral elongation of the first deflectable film structure (14).

8. The MEMS device (10) according to any one of claims 1 to 6, wherein the second elongation element (42) is formed as a lateral elongation of the second deflectable film structure (18).

9. The MEMS device (10) according to any one of claims 1 to 8, wherein the edge clamping regions (26-1, ..., 26-#) of the transducer element (12) and the edge clamping regions (38-1, ..., 38-#) of the elongation structure (32) are arranged in an alternating order.

10. The MEMS device (10) according to any one of claims 1 to 9, wherein the carrier element (22) includes a groove (46), and wherein the transducer element (12) and the elongation structure (32) are arranged to cover the groove (46) in the carrier element (22).

11. The MEMS device (10) according to any one of claims 1 to 10 further includes a wall structure (44) at the unclamped edge region (34-1, ..., 34-#) of the transducer element (12).

12. The MEMS device (10) of claim 11, wherein the first deflectable film structure (14) and the second deflectable film structure (18) and the wall structure (44) together form a cavity (48) relative to an environment (50), wherein the cavity (48) is sealed relative to the environment (50), and the cavity (48) includes a low-pressure region, wherein the low-pressure region includes reduced atmospheric pressure compared to the ambient atmosphere.

13. The MEMS device (10) according to any one of the preceding claims, wherein the mechanical connection element (20) comprises a plurality of pillar-like or columnar mechanical connection elements between two opposing deflectable membrane structures (14, 18).

14. The MEMS device (10) according to any one of the preceding claims, wherein the rigid electrode structure (16) forms a counter electrode with respect to the first deflectable film structure (14) and / or the second deflectable film structure (18).

15. The MEMS device (10) according to any one of the preceding claims, wherein the transducer element (12) has a microphone and / or speaker function.

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