MEMS component with in-plane movable element

Description

Technical area

[0001] The present disclosure relates to micromechanical systems (MEMS). In particular, embodiments relate to a MEMS component, an assembly including the MEMS component, and methods for operating the MEMS component. background

[0002] MEMS components can be used in a variety of ways to interact with an ambient gas or liquid. For example, MEMS components can be used to excite an ambient gas to vibrate. Such MEMS components can be used in loudspeakers, for example. MEMS components can also be used to detect vibrations of an ambient gas. Such MEMS components can be used in microphones, for example.

[0003] Furthermore, a variety of passive elements that can be connected to deflectable actuators are proposed in the literature. Examples include the numerous micromirror applications. Likewise, membranes for loudspeakers or microphones can also be considered passive elements. However, all technologies have in common that the deflection of the passive elements occurs out of the substrate plane (out-of-plane).

[0004] In-plane movement of a passive element driven by micromechanical actuators is proposed in document DE 10 2017 206 766 A1. In this case, deflectable elements are connected to a surrounding substrate on one side. The respective freely movable ends are connected to plates via spring elements or rigid elements and can thus transmit forces to the plate. At least two such plates are arranged opposite one another and laterally close off a cavity that is connected to the environment through an opening in the substrate. To accommodate the changing geometric dimensions of the actuators during deflection, the plates must be connected to the actuators via spring elements. This has a detrimental effect on the performance of the resulting transducers, as the springs influence the vibration characteristics of the overall system.

[0005] A MEMS element that can achieve high sound pressure with a minimized component surface area would be desirable. The MEMS element should provide a large fluidic effective area in the substrate plane for interaction with the surrounding fluid (ambient fluid) while simultaneously minimizing the capacitance of the component surface.

[0006] Against this background, one task is to provide an improved MEMS structure for interaction with an ambient fluid. Summary

[0007] This object is achieved according to the invention by a MEMS component according to the independent claim. Further aspects and developments of the invention are described in the dependent claims, the following description, and the figures.

[0008] The invention therefore relates to a MEMS component comprising a layer stack with at least one second layer formed between a first layer and a third layer. At least one first cavity is formed in the second layer. The MEMS component further comprises a laterally deflectable element having an end connected to a side wall of the first cavity and a free end. The laterally deflectable element is deflectable in the plane of the second layer. Furthermore, the MEMS component comprises a passive element rigidly connected to the free end of the laterally deflectable element in order to follow a movement of the laterally deflectable element. The laterally deflectable element and the passive element divide the first cavity into a first partial cavity and a second partial cavity. The first partial cavity is in contact with an ambient fluid of the MEMS component via at least one first opening.Furthermore, the second partial cavity is in contact with the ambient fluid of the MEMS component via at least one second opening. The at least one second opening is formed in the first layer or the third layer. The at least one first opening is formed in a different layer of the first layer and the third layer than the at least one second opening.

[0009] The passive element is rigidly connected to the laterally deflectable element. Due to the lower mass of the passive element compared to the laterally deflectable element, higher accelerations can be achieved, especially during changes in the direction of the lateral movement of the system formed by the passive element and the laterally deflectable element, so that the system can achieve more constant velocities across the deflection range. This enables higher resonance frequencies for the lateral movement and allows interaction with larger amounts of ambient fluid. The system formed by the passive element and the laterally deflectable element also enables large volumes for the first and second partial cavities, resulting in only a comparatively low (unwanted) electrical capacitance per unit area. Short character description

[0010] Some examples of devices and / or methods are explained in more detail below with reference to the accompanying figures. They show: Fig. 1 a plan view of a first embodiment of a MEMS component; Fig. 2 a sectional view along the section axis AA through the first embodiment of the MEMS component; Fig. 3 a sectional view along the section axis BB through the first embodiment of the MEMS component; Fig. 4 a sectional view along the section axis EE through the first embodiment of the MEMS component; Fig. 5 a plan view of a second embodiment of a MEMS component; Fig. 6 a sectional view along the section axis CC through the second embodiment of the MEMS component; Fig. 7 a sectional view along the section axis DD through the second embodiment of the MEMS component; Fig. 8a plan view of a third embodiment of a MEMS component; Fig. 9 and 10 Examples of the passive element; Fig. 11 a plan view of a fourth embodiment of a MEMS component; Fig. 12 an embodiment of an assembly with at least one MEMS component; Fig. 13 a flowchart of a first embodiment of a method for operating a MEMS component; and Fig. 14 a flowchart of a second embodiment of a method for operating a MEMS component. Description

[0011] Various examples will now be described in more detail with reference to the accompanying figures, which illustrate some examples. In the figures, the thicknesses of lines, layers, and / or regions may be exaggerated for clarity.

[0012] Accordingly, while further examples are susceptible to various modifications and alternative forms, certain specific examples thereof are shown in the figures and are described in detail below. However, this detailed description is not limited to the specific forms described. Further examples may cover all modifications, equivalents, and alternatives that fall within the scope of the disclosure. Like or similar reference numerals refer to like or similar elements throughout the description of the figures, which, when compared to one another, may be implemented identically or in modified form while providing the same or a similar function.

[0013] It is understood that when an element is referred to as being "connected" or "coupled" to another element, the elements may be connected or coupled directly or through one or more intermediate elements. When two elements A and B are combined using an "or," this is to be understood as disclosing all possible combinations, i.e., only A, only B, and both A and B, unless explicitly or implicitly defined otherwise. An alternative formulation for the same combinations is "at least one of A and B" or "A and / or B." The same applies, mutatis mutandis, to combinations of more than two elements.

[0014] The terminology used here to describe specific examples is not intended to be limiting for further examples. Where a singular form, such as "a," "an," and "the," is used, and the use of only a single element is neither explicitly nor implicitly defined as mandatory, further examples may also use plural elements to implement the same function. Where a function is subsequently described as being implemented using multiple elements, further examples may implement the same function using a single element or a single processing entity.It is further understood that the terms "comprises", "comprising", "comprises" and / or "having" when used specify the presence of the specified features, integers, steps, operations, processes, elements, components and / or a group thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, processes, elements, components and / or a group thereof.

[0015] Unless otherwise defined, all terms (including technical and scientific terms) are used herein in their ordinary meaning in the field to which examples belong.

[0016] Fig. 1 shows a top view of a first MEMS component 100. In particular, Fig. 1 a top view of a second layer 112 of a layer stack 110 from which the MEMS component 100 is constructed or formed. The structure of the layer stack 110 is

[0017] Fig. 2 which shows a sectional view of the MEMS component 100 along the Fig. 1 indicated section line AA.

[0018] Out of Fig. 2 It can be seen that the layer stack 110 comprises at least a first layer 111, a second layer 112, and a third layer 113. The second layer 112 is formed between the first layer 111 and the third layer 113. In the second layer 112 (which can also be understood as a device plane, device layer, or device wafer), at least one first cavity 114 is formed, in which the further elements of the MEMS component 100 are arranged. The second layer 112 can therefore also be understood as a substrate layer. Optionally, further cavities can be formed in the second layer 112.

[0019] The first layer 111 serves as a base layer for the second layer 112 (and can also be considered a handling wafer). The third layer 113 serves as a lid layer for the second layer 112 (and can also be considered a lid wafer). The first layer 111 and the third layer 113 define the first cavity 114 along the thickness direction of the layer stack 110.

[0020] Layers 111 to 113 may comprise electrically conductive materials such as doped semiconductor materials (e.g., doped silicon) or metal materials. Furthermore, layers 111 to 113 may have coated surfaces (e.g., metal on undoped silicon or polymers). The layer-by-layer arrangement of electrically conductive layers enables simple design and structuring, since active elements (e.g., electrodes) as well as passive elements can be formed by selectively dissolving material from the respective layer. Likewise, layers 111 to 113 may comprise electrically non-conductive materials. The electrically non-conductive materials may be introduced into one of layers 111 to 113, for example, by means of deposition processes.

[0021] For example, the first layer 111, the second layer 112, and the third layer 113 can each be a wafer. The individual wafers are connected to each other in pairs using material-to-material processes (e.g., bonding) to obtain the layer stack 110 with the layer sequence described above. Accordingly, the first cavity 114 can be formed as an acoustically sealed gap in the MEMS component 100.

[0022] Arranged in the first cavity 114 is a laterally deflectable element 120, which has an end 121 connected to a side wall 115 of the first cavity 114 and a free end (or a freely movable end) 122. In other words, the laterally deflectable element 120 is connected to the surrounding substrate on one side. The term "laterally deflectable" is to be understood to mean that the laterally deflectable element 120 is capable of performing a movement in the plane of the second layer 112, i.e., an in-plane movement. In other words, the laterally deflectable element 120 can move within the plane of the second layer 112, but not vertically to the plane of the second layer 112 (i.e., out of the plane of the second layer 112).

[0023] The laterally deflectable element 120 can be designed or constructed in various ways. Regardless of the specific structure of the laterally deflectable element 120, it is designed to deform laterally upon application of a first potential (e.g., a first voltage signal as a control signal) and / or to output a second potential (e.g., a second voltage signal as an evaluation signal) upon lateral deformation due to an external force. In other words, the laterally deflectable element 120 is designed to provide a force via a movement or deformation in response to an actuation (i.e., to act as an actuator) and / or to detect a force by means of deformation (i.e., to act as a sensor).For example, the laterally deflectable element 120 can be configured as an electromechanical transducer, piezoelectric transducer, magnetostrictive transducer, thermomechanical transducer, or a combination thereof to convert the respective energy form or potential into mechanical energy and vice versa. Based on a respective applied potential, a corresponding deformation of the laterally deflectable element 120 can be provided in the plane of the second layer 112, or, in the case of lateral deformation due to an external force, a corresponding potential can be provided by the laterally deflectable element 120.

[0024] The Fig. 1 and 2The laterally deflectable element 120 shown is designed as an electrostatic transducer and has opposing, first, second, and third deflectable or laterally deformable sub-elements 123, 124, and 125, which are spaced apart from one another and electrically connected to one another. The laterally deformable sub-elements 123, 124, and 125 each have a concavely curved shape. In other words, the laterally deflectable element 120 is Fig. 1designed as a three-cell, balanced element. In the simplest case, each of the laterally deformable sub-elements 123, 124, and 125 has a three-layer structure with two geometrically differently shaped electrode layers that are connected to one another via a non-conductive layer, which may be interrupted. When a potential is applied between the at least two electrode layers, an electric field is generated, as a result of which the electrode layers deform laterally (e.g., by changing their length). Due to the mechanical fixation of the laterally deflectable element 120 to the side wall 115 of the cavity 114, the degrees of freedom of the resulting deformation are limited, so that deformation (curvature or deflection) occurs in the plane of the second layer 112.The use of three laterally deformable sub-elements 123, 124 and 125 for the laterally deflectable element 120 enables a high and adjustable linearity of the laterally deflectable element 120.

[0025] Deflectable elements, and in particular laterally deflectable elements, comprising at least a first electrode layer and a second electrode layer between which a non-conductive layer is formed, are also known as nanoscopic electrostatic drives (NEDs). Exemplary embodiments of NEDs are described in the patent applications WO 2012 / 095185 A1, WO 2016 / 202790 A2, and DE 10 215 / 206 774 A1 of the Fraunhofer Society for the Promotion of Applied Sciences.

[0026] Lateral NEDs (L-NEDs) deform laterally upon application of a first voltage signal to the first electrode layer and the second electrode layer. Furthermore, L-NEDs generate a second voltage signal at the first electrode layer and the second electrode layer upon lateral deformation due to an external force. The laterally deflectable element 120 can thus be configured as a NED according to some embodiments. DE 10 2017 203722 A1 discloses a MEMS with a substrate having a cavity. The MEMS comprises a movable element arranged in the cavity, comprising a first electrode, a second electrode, and a third electrode arranged between the first and second electrodes and fixed to discrete regions in an electrically insulated manner.The movable element is designed to perform a movement along a movement direction in a substrate plane in response to an electrical potential between the first electrode and the third electrode and / or in response to an electrical potential between the second electrode and the third electrode.

[0027] As will be apparent from the further embodiments, the shape of the laterally deflectable element 120 is not limited to the Fig. 1 The shape of the laterally deflectable element 120 can be limited to the concavely curved shape shown. In principle, the shape of the laterally deflectable element 120 can be arbitrary (e.g., beam-like, roof-like, etc.). For example, the laterally deflectable element 120 can alternatively be designed as a two-cell, balanced element or as a beam-shaped element constructed from at least two spaced-apart electrodes.

[0028] A passive element 130 is rigidly (i.e., fixed, immovable, or non-elastic) connected to the free end 122 of the laterally deflectable element 120 to follow any movement of the laterally deflectable element 120. Unlike the laterally deflectable element 120, the passive element 130 cannot deform and is therefore "passive." The passive element 130 can be formed from a variety of materials. For example, the passive element 130 can be formed from the same material as the second layer 112.

[0029] Two possible lateral deflection ranges of the passive element 130 are shown in Fig. 1 On the one hand, a deflection range 135 for a quasi-static excitation of the laterally deflectable element 120 (ie for a quasi-static case) is Fig. 1and on the other hand, a deflection region 136 for a resonant excitation of the laterally deflectable element 120 (ie for a resonant case) is shown in Fig. 1 shown.

[0030] According to embodiments, a stiffness of the passive element 130 is greater than or equal to a stiffness of the laterally deflectable element 120. In other words, the stiffness of the passive element 130 is at least comparable to that of the laterally deflectable element 120.

[0031] Laterally, the first cavity 114 is further delimited by two further side walls 116 and 117. The further side walls 116 and 117 can be regarded as the edge of the first cavity 114. The laterally deflectable element 120 as well as the passive element 130 each extend along their longitudinal extent between the two further side walls 116 and 117. As can be seen in particular from the left part of Fig. 1As can be seen, the respective courses of the further side walls 116 and 117 are at least partially adapted to an outer contour of the laterally deflectable element 120.

[0032] Furthermore, a T-shaped partition 118 is formed in the first cavity 114. The partition 118, together with the laterally deflectable element 120 and the passive element 130, divides the first cavity 114 into a first partial cavity 114-1 and a second partial cavity 114-2. A gap is formed between the partition 118 and the free end 132 of the passive element 130 to allow movement of the passive element 130 relative to the partition 118. However, the gap is so small that a (significant) volume flow of the ambient fluid through the gap is not possible. In other words: Between the partition wall 118 and the free end 132 of the passive element 130, a (small) free space is formed, the dimensions of which are so small that no (significant) volume flow between the adjacent partial cavities 114-1 and 114-2 is possible through the free space.For example, the distance between the partition 118 and the free end 132 of the passive element 130 may be less than 10 µm, 5 µm, or 3 µm.

[0033] Each of the partial cavities 114-1 and 114-2 is in contact with an ambient fluid (e.g., a gas or liquid) surrounding the MEMS component 100 via at least one respective opening. The first partial cavity 114-1 is in contact with the ambient fluid of the MEMS component 100 via at least one first opening 140-1. The second partial cavity 114-2 is in contact with the ambient fluid of the MEMS component 100 via at least one second opening 150-1. Fig. 1In the MEMS component 100 shown, the first partial cavity 114-1 is in contact with the ambient fluid of the MEMS component 100 via two first openings 140-1 and 140-2. One of the two first openings, namely the first opening 140-1, is arranged in a region of the first partial cavity 114-1 in which the laterally deflectable element 120 extends. The other of the two first openings, namely the first opening 140-2, is arranged in a different region of the first partial cavity 114-1. In the Fig. 1In the illustrated embodiment, the first opening 140-2 is arranged in the region of the partition wall 118 at the free end 132 of the passive element 130. Equivalently, the second partial cavity 114-2 is in contact with the ambient fluid of the MEMS component 100 via two second openings 150-1 and 150-2. It should be noted that the number of first or second openings can be freely selected. For example, n = 1, 2, 3 or more openings can be provided for each of the partial cavities. The placement of the opening can also be freely selected, in particular different from the Fig. 1 shown positions (e.g. in the area of ​​the free end 132 of the passive element 130).

[0034] The at least one first opening 140-1 is formed in a different layer of the first layer 111 and the third layer 113 than the at least one second opening 150-1. This is shown, for example, in Fig. 3 and Fig. 4which each show a sectional view of the MEMS component 100 along the Fig. 1 The section lines BB and EE are indicated. Fig. 3 and Fig. 4 In the embodiment shown, the first openings 140-1 and 140-2 are formed in the first layer 111, while the second openings 150-1 and 150-2 are formed in the third layer 113. In this way, an acoustic short circuit between adjacent partial cavities of the first cavity 114 can be avoided. It should be noted that the first openings 140-1 and 140-2 can alternatively also be formed in the third layer 113, and the second openings 150-1 and 150-2 can correspondingly be formed in the first layer 111.

[0035] The at least one first opening and the at least one second opening are arranged such that the laterally deflectable element 120 and the passive element 130 cannot cover the openings even at maximum lateral deflection, in order to avoid an acoustic short circuit between the two partial cavities 114-1 and 114-2. There is (essentially) no exchange of fluid between the first partial cavity 114-1 and the second partial cavity 114-2 due to the subdivision of the first cavity 114 by the laterally deflectable element 120, the passive element 130, and the partition wall 118.

[0036] The volumes of the partial cavities 114-1 and 114-2 can be changed by lateral movement of the laterally deflectable element 120 and the passive element 130. The volume-variable partial cavities 114-1 and 114-2 serve to interact with the ambient fluid. Pressure equalization in the partial cavities 114-1 and 114-2 occurs via the at least one first opening 140-1 and the at least one second opening 150-1 when the volume changes.

[0037] As already explained above, the laterally deflectable element 120 is designed to deform laterally upon application of a first potential, so that the laterally deflectable element 120 and the passive element 130 move relative to the further side walls 116 and 117 of the first cavity 114 in order to influence the ambient fluid by alternately reducing and increasing the volume of the first partial cavity 114-1 and conversely by alternately increasing and decreasing the volume of the second partial cavity 114-2. Via the openings 140-1 and 140-2 or 150-1 and 150-2, the changes in the volumes of the partial cavities 114-1 and 114-2 act on the ambient fluid present in the environment of the MEMS component 100 and thereby influence it. Accordingly, the MEMS component 100 acts as an actuator.

[0038] Conversely, the laterally deflectable element 120 and the passive element 130 can move laterally relative to the further side walls 116 and 117 of the first cavity 114 in order to adjust the volumes of the first partial cavity 114-1 and the second partial cavity 114-2 depending on the ambient fluid, while deforming the laterally deflectable element 120. For example, depending on pressure conditions or pressure gradients in the ambient fluid, the volume of the first partial cavity 114-1 can be reduced and the volume of the second partial cavity 114-2 can be increased, so that the laterally deflectable element 120 and the passive element 130 are displaced laterally relative to the further side walls 116 and 117 of the first cavity 114, and the laterally deflectable element 120 is deformed accordingly.As explained above, the laterally deflectable element 120 is designed to output a second potential upon lateral deformation due to an external force by the displacement of the laterally deflectable element 120 and the passive element 130 relative to the further side walls 116 and 117 of the first cavity 114.

[0039] If the laterally deflectable element 120 comprises, as described above, for example, a first electrode layer and a second electrode layer between which a non-conductive layer is formed, the laterally deflectable element 120 can be designed accordingly to deform laterally upon application of a first voltage signal (as an example of a first potential) to the first electrode layer and the second electrode layer, and / or to generate a second voltage signal (as an example of a second potential) at the first electrode layer and the second electrode layer upon lateral deformation due to an external force.

[0040] The combination of laterally deflectable element 120 and passive element 130 forms a large area for interaction with the ambient fluid. The MEMS component 100 can thus provide an enlarged fluidic effective area. The MEMS component 100 can be used both to influence the ambient fluid, i.e., as an actuator, and to measure the ambient fluid, i.e., as a sensor. Due to the previously described design, the passive element 130 has a comparatively low mass, so that high accelerations can be achieved, especially during changes in direction of the lateral movement, and the portion of the deflection range that the transducer exceeds at a more constant speed increases accordingly within the deflection range of the transducer. This has a positive effect on the resonance frequencies achievable for the lateral movement. Furthermore, it is possible to interact with a larger amount of ambient fluid.

[0041] The small dimensions of the passive element 130 compared to the laterally deflectable element 120 enable large volumes of the partial cavities 114-1 and 114-2.

[0042] This enables high packing densities with a large fluidic effective area. At the same time, the capacitance per unit area of ​​the MEMS component or converter system (i.e., the electrical capacitance of a specific chip surface of the MEMS component) is advantageously reduced.

[0043] In some embodiments, an extension of the passive element 130 along a thickness direction of the second layer 112 is equal to an extension of the laterally deflectable element 120 along the thickness direction of the second layer 112. In other words, the height of the passive element 130 can be equal to a height of the laterally deflectable element 120. Alternatively, the extension of the passive element 130 along the thickness direction of the second layer 112 can be at least partially less than the extension of the laterally deflectable element 120 along the thickness direction of the second layer 112. For example, the extension of the passive element 130 along the thickness direction of the second layer 112 can be at least partially 5 to 10 µm less than the extension of the laterally deflectable element 120 along the thickness direction of the second layer 112.A lower height of the passive element 130 compared to the laterally deflectable element 120 can enable the fluid load to be adapted to the performance of the laterally deflectable element 120. Likewise, the height can be used to adjust the fluid stiffness to the stiffness of the laterally deflectable element 120. Alternatively, this could also be achieved by varying the longitudinal extent of the passive element 130. Varying the height of the passive element 130 has the advantage over varying the longitudinal extent that the fill factor of the first cavity 114 is maintained (i.e., the volume of the first cavity does not need to be changed).

[0044] The extensions of the passive element 130 and of the laterally deflectable element 120 along the thickness direction of the second layer 112 are selected such that only a small gap remains between the passive element 130 and the laterally deflectable element 120 and the first layer 111 (i.e., the handling wafer) and the third layer 113 (i.e., the lid wafer). In particular, the extensions of the passive element 130 and of the laterally deflectable element 120 along the thickness direction of the second layer 112 are selected such that no (significant) volume flow is possible between the adjacent partial cavities 114-1 and 114-2 due to the free space between the passive element 130 and the laterally deflectable element 120 and the first layer 111 and the third layer 113. For example, the distance between the passive element 130 or the laterally deflectable element 120 and the first layer 111 orthe third layer 113 can be less than 10 µm, 5 µm, or 3 µm. Accordingly, an acoustic short circuit between the partial cavities 114-1 and 114-2 can be avoided.

[0045] As is particularly evident from Fig. 1 As can be seen, a cross-section of the passive element 130 along its longitudinal extent is smaller than a cross-section of the laterally deflectable element 120 along its longitudinal extent. In other words: In the direction of movement of the laterally deflectable element 120 (i.e., in the lateral direction), the geometric spread of the passive element 130 is (significantly) smaller than the geometric spread of the laterally deflectable element 120.

[0046] The cross section of the passive element 130 along its longitudinal extent can be as in Fig. 1 shown constant (ie unchanged). Alternatively, the cross section of the passive element 130 may also change along its longitudinal extent. This is shown in Fig. 5shown. In the Fig. 5In the MEMS component 500 shown, the cross-section of the passive element 130 decreases from the end 131 of the passive element 130 connected to the laterally deflectable element 120 to a free end 132 of the passive element 130; otherwise, the MEMS component 500 is constructed identically to the MEMS component 100. In other words: the passive element 130 tapers from the end 131 connected to the laterally deflectable element 120 to the free end 132 of the passive element 130. The connection point of the passive element 130 to the laterally deflectable element 120 thus has the largest geometric dimensions, while the freely oscillating end 132 of the passive element 130 has the smallest geometric dimensions. For example, the passive element 130 may taper in the plane of the second layer 112, wherein the pointed end of the passive element 130 is the free end 132 of the passive element 130. This is further Fig. 6 and Fig. 7which each show a sectional view of the MEMS component 500 along the Fig. 5indicated intersection lines CC and DD. While the width (i.e., the lateral extent) of the passive element 130 at the intersection line CC is still b 1, the width of the passive element 130 at the intersection line DD, which is closer to the free end 132 of the passive element 130 than the intersection line CC, is only b 2 (where b 2 < b 1 ). The greater width of the passive element 130 in the connection area between the passive element 130 and the laterally deflectable element 120 compared to the width at the free end 132 of the passive element 130 enables a homogeneous stress transfer between the free end 122 of the laterally deflectable element 120 and the passive element 130.The stresses resulting from the resistance of the passive element 130 to the ambient fluid and the inertia of the passive element 130 when the acceleration changes can be homogeneously transferred to the laterally deflectable element 120 due to the larger width at the end 131 of the passive element 130. The reduced mass or inertia of the passive element 130 due to the tapering of the passive element 130 improves the dynamic behavior of the transducer system formed by the passive element 130 and the laterally deflectable element 120.

[0047] Regardless of whether the cross-section of the passive element 130 varies along the longitudinal extent of the passive element 130 or is constant, the ratio of the longitudinal extent of the passive element 130 to its lateral extent is greater than, for example, 10:1, 20:1, 30:1, 40:1, or 50:1. In other words, the passive element 130 is significantly longer than it is wide and can therefore also be considered a "rod-shaped" element.

[0048] The longitudinal extension of the passive element 130 can be selected depending on the desired dynamic behavior of the system comprising the passive element 130 and the laterally deflectable element 120. The achievable resonance frequency of the system comprising the passive element 130 and the laterally deflectable element 120 can be adjusted by selecting the length of the passive element 130. It should be noted that the achievable resonance frequency decreases with increasing length of the passive element 130. For example, a longitudinal extension of the passive element can be between 20% and 160%, in particular between 30% and 50% or between 60% and 100%, or even 80%, of a longitudinal extension of the laterally deflectable element 120.

[0049] As already indicated several times in the description of the individual elements of the MEMS components 100 and 500, the individual elements of a MEMS component according to the proposed architecture can be compared to the Fig. 1 and Fig. 5The MEMS components 100 and 500 shown can be modified in many ways. Therefore, some additional MEMS components according to the proposed architecture are described in more detail below, primarily highlighting the differences from the MEMS components 100 and 500 described in detail above.

[0050] Fig. 8 shows a MEMS component 800 with a laterally deflectable element 120 that is differently designed compared to the MEMS components 100 and 500. While the laterally deflectable element 120 of the MEMS components 100 and 500 is each formed from three sub-elements with a concavely curved shape, the laterally deflectable element 120 of the MEMS component 800 consists of only two sub-elements with a concavely curved shape. In other words: the laterally deflectable element 120 is a two-cell, balanced element in Fig. 8Furthermore, in the exemplary embodiment, the longitudinal extent of the passive element 130 is smaller than the longitudinal extent of the laterally deflectable element 120. Likewise, the MEMS component 800 does not have a partition wall.

[0051] The design of the MEMS component 800 is advantageous for confined spaces where longer, laterally deflectable elements with a higher number of cells cannot be used. Thus, the available area for interaction with the ambient fluid is maximized.

[0052] In Fig. 9 and 10 It is also shown how the passive element 130 can be adapted to the respective situation using appropriate geometries. Fig. 9 shows a sectional view through the passive element 130 (e.g. along one of the section lines CC and DD in Fig. 5) to indicate various possible cross-sections for the passive element 130. For example, the passive element 130 can have a bar-shaped or rectangular (see top left), a wedge-shaped (see top right), a concave (see bottom left), or an oval (see bottom right) cross-section.

[0053] Fig. 10 shows a top view of the passive element to indicate further design possibilities for the passive element. In particular, the Fig. 10 several versions of the passive element with improved lightweight construction potential. Fig. 10In the embodiments 130-a, 130b, and 130-c shown, at least one cavity 133-1, ..., 133-8 is formed in the passive element. By means of the cavity(ies), an improved mass-to-stiffness ratio can be achieved at the end 131 of the passive element connected to the laterally deflectable element 120. For example, material of the passive element can be removed by means of one or more etching processes in order to form the cavity(ies) 133-1, ..., 133-8.

[0054] As in the embodiment 130-d, which is shown in Fig. 10 As indicated, an improved mass-stiffness ratio can also be achieved by means of an optimized geometry or outer contour in the region of the end 131 of the passive element connected to the laterally deflectable element 120.

[0055] In Fig. 11A MEMS component 1100 is shown in which a plurality of cavities with the structure described above are formed in the second layer 112. Although in Fig. 11 five cavities are shown, it should be noted that a MEMS component according to the invention may also have any other plurality of cavities. For example, a MEMS component according to the invention may also have 2, 3, 4, 6, 10, 20 or more of the cavities described above. As can be seen from Fig. 11As can be seen, the individual cavities are arranged alternately in the second layer 112, so that adjacent cavities are rotated by 180° to one another and each have a common side wall (in alternative exemplary embodiments, the cavities can also be arranged in the same direction, i.e. not rotated to one another). In other words: the transducer systems arranged in the cavities are arranged adjacent to one another along a first spatial direction and extend (longitudinally) essentially along a second spatial direction which is perpendicular to the first spatial direction. The transducer systems are suspended alternately on opposite sides of the surrounding substrate of the second layer 112. This will be explained again explicitly below with reference to the first cavity 114 and the second cavity 1114, which are adjacent to one another.

[0056] The first cavity 114 is designed essentially as described above and additionally has a third, second opening 150-3. Reference is therefore made to the above explanations.

[0057] Accordingly, a further laterally deflectable element 1120 is formed in the second cavity 1114, which has an end 1121 connected to a side wall 1115 of the second cavity 1114 and a free end 1122. The further laterally deflectable element 1120 is in the embodiment of the Fig. 11 identical to the laterally deflectable element 120. In alternative embodiments, the further laterally deflectable element 1120 and the laterally deflectable element 120 can also be designed differently (for example, have a different geometry or a different number of sub-elements).

[0058] The side wall 115 of the first cavity 114, to which the laterally deflectable element 120 is attached, and the side wall 1115 of the second cavity 1114, to which the further laterally deflectable element 1120 is attached, lie opposite one another. The first cavity 114 and the second cavity 1114 are delimited by the common further side wall 117, which runs along the longitudinal extent of the laterally deflectable element 120 and along the longitudinal extent of the further laterally deflectable element 1120.

[0059] A further passive element 1130 is rigidly connected to the free end 1122 of the further laterally deflectable element 1120 in order to follow a movement of the further laterally deflectable element 1120. The further passive element 1130 is in the embodiment of the Fig. 11identical to the passive element 130. In alternative embodiments, the further passive element 1130 and the passive element 130 may also be differently configured (for example, have a different geometry or a different length).

[0060] Analogous to the above explanations for the first cavity 114, the further laterally deflectable element 1120 and the further passive element 1120 together with the further partition wall 1118 divide the second cavity 1114 into a third partial cavity 1114-1 and a fourth partial cavity 1114-2.

[0061] The adjacent cavities 114 and 1114 are arranged in the MEMS component 1100 such that the respective laterally deflectable element 120 or 1120 is opposite the passive element 1130 or 130 of the adjacent cavity.

[0062] The third partial cavity 1114-1 is in contact with the ambient fluid of the MEMS component 1110 via three third openings 1140-1, 1140-2 and 1140-3. Accordingly, the fourth partial cavity 1114-2 is in contact with the ambient fluid of the MEMS component 1100 via three fourth openings 1150-1, 1150-2 and 1150-3. Analogous to the above explanations for the first and third openings, it should be noted that the Fig. 11 The number of openings shown is exemplary and serves purely for illustration purposes. According to embodiments, any number (n ≥ 1) of openings can be used to bring the third partial cavity 1114-1 and the fourth partial cavity 1114-2 into contact with the ambient fluid.

[0063] The third openings 1140-1, 1140-2 and 1140-3 are in turn formed in a different layer of the first layer 111 and the third layer 113 than the fourth openings 1150-1, 1150-2 and 1150-3 in order to avoid an acoustic short circuit between the third partial cavity 1114-1 and the fourth partial cavity 1114-2.

[0064] The second openings 150-1, 150-2 and 150-3 are in the embodiment of the Fig. 11 in the same layer of the first layer and the third layer as the fourth openings 1150-1, 1150-2 and 1150-3. As can be seen from Fig. 11As can be seen, the second opening 150-1 and the fourth opening 1150-3, as well as the second opening 150-3 and the fourth opening 1150-1, each form a contiguous opening. The second partial cavity 114-2 is thus short-circuited with the adjacent fourth partial cavity 1114-2. This is possible because the lateral movement of the further passive element 1130 and the further laterally deflectable element 1120 is opposite to the movement of the passive element 130 and the laterally deflectable element 120, so that the volumes of the second partial cavity 114-2 and the fourth partial cavity 1114-2 change essentially in the same way. The adjacent cavities 114 and 1114 are thus connected to one another in regions in which the respective laterally deflectable element 120 or 1120 is opposite the passive element 1130 or 130 of the adjacent cavity.

[0065] Out of Fig. 11It is further apparent that the at least partial adaptation of the respective profiles of the further side walls 116 and 117 to the outer contour of the laterally deflectable element 120 enables an increase in the volume of the adjacent cavities in the region of the free end of their respective passive elements. For example, the adaptation of the profile of the side wall 117 to the curved contour of the first cell of the laterally deflectable element 120 enables an increase in the volume of the second cavity 1114 in the region of the free end 1132 of the further passive element 1130 or in the region of the dividing wall 1118 of the second cavity 1114. The laterally deflectable element 120 undergoes its least deformation in this region, so that the oval configuration of the side wall 117 in this region enables a maximization of the volume of the second cavity 1114. Accordingly, the second cavity 1114 can interact with a larger volume of the ambient fluid.

[0066] The statements made for cavities 114 and 1114 also apply analogously to the other cavities of the MEMS component 1100.

[0067] While the previous sections have focused on the details of MEMS devices according to the proposed architecture, the following sections will focus on the application of MEMS devices.

[0068] For this purpose, Fig. 12 An assembly 1200 is shown. The assembly 1200 comprises at least one MEMS component 1210 according to the proposed architecture or one of the embodiments described herein. If the assembly 1200 comprises a plurality of MEMS components 1210, the plurality of MEMS components 1210 can be aligned essentially arbitrarily with respect to one another. For example, the plurality of MEMS components 1210 can be formed on a common semiconductor chip or a semiconductor die.

[0069] Depending on the type of assembly 1200, the assembly may include a control circuit 1220 and / or a measurement circuit 1230.

[0070] The control circuit 1320 is configured to provide at least a first potential (e.g., a first voltage signal, a first magnetic potential, or a first thermal potential) for the laterally deflectable element of the at least one MEMS component 1210 in order to operate the laterally deflectable element as an actuator for influencing the ambient fluid.

[0071] The measuring circuit 1330 is configured to measure at least a second potential (e.g., a second voltage signal, a second magnetic potential, or a second thermal potential) of the laterally deflectable element of the at least one MEMS component 1210 in order to operate the laterally deflectable element as a sensor for the ambient fluid.

[0072] If the at least one MEMS component 1210 is to be operated as an actuator, the assembly 1200 includes the control circuit 1220. For example, the assembly 1200 can be a headphone, a loudspeaker, a loudspeaker of a headphone, a loudspeaker of an (ultra-)mobile terminal, or the like, such that the ambient fluid surrounding the at least one MEMS component 1210 is influenced via the at least one MEMS component 1210 to output a sound signal. According to further embodiments, the assembly 1200 can also be a fluid pump, such that the ambient fluid surrounding the at least one MEMS component 1210 is influenced via the at least one MEMS component 1210 to transport the fluid.

[0073] If the at least one MEMS component 1210 is to be operated as a sensor, the assembly 1200 includes the measuring circuit 1230. For example, the assembly 1200 can be a microphone that enables sensing of the ambient fluid surrounding the at least one MEMS component 1210 via the at least one MEMS component 1210.

[0074] If the assembly 1200 comprises a plurality of MEMS components 1210, according to embodiments, a first portion of the plurality of MEMS components 1210 can be operated as actuators and a second portion of the plurality of MEMS components 1210 can be operated as sensors. For example, the assembly 1200 in this embodiment can be a headset with active noise cancellation.

[0075] To summarize the aspects described above for operating the MEMS components described herein, the Figs. 13 and 14Flow diagrams of two methods for operating the MEMS components described herein are also shown.

[0076] Fig. 13 shows a flowchart of a first method 1300 for operating a MEMS component described herein. The method 1300 comprises a lateral deformation 1302 of the laterally deflectable element in a first direction by applying a potential (e.g., a voltage signal) in order to increase a volume of the first partial cavity and to decrease a volume of the second partial cavity during a first time interval for influencing the ambient fluid. Furthermore, the method 1300 comprises a lateral deformation 1304 of the laterally deflectable element in an opposite second direction by applying the potential in order to increase the volume of the second partial cavity and to decrease the volume of the first partial cavity during a second time interval for influencing the ambient fluid.

[0077] Method 1300 can enable a controlled influence on the ambient fluid based on the applied potential. Due to the design of the laterally deflectable element and the passive element in the cavity, the available area of ​​the MEMS component can be used to a large extent to influence the ambient fluid. Method 1300 can be used to operate the MEMS component as an actuator.

[0078] Further details and aspects of the method 1300 are described above in connection with further embodiments (e.g. Figs. 1 to 10 ). The method 1300 may include one or more optional features according to the further embodiments. Fig. 14shows a flowchart of a second method 1400 for operating a MEMS component described herein, in which the laterally deflectable element and the passive element can move laterally relative to side walls of the first cavity in order to adjust volumes of the first partial cavity and the second partial cavity depending on the ambient fluid. The method 1400 includes outputting 1402 a potential (e.g., a voltage signal) by the laterally deflectable element upon lateral deformation due to an external force caused by the displacement of the laterally deflectable element and the passive element relative to the side walls of the first cavity. Due to the design of the laterally deflectable element and the passive element in the cavity, the available area of ​​the MEMS component can be utilized to a high degree for sensing the ambient fluid. The method 1400 can be used for operating the MEMS component as a sensor.

[0079] Further details and aspects of the method 1400 are described above in connection with further embodiments (e.g. Figs. 1 to 10 ). The method 1400 may include one or more optional features according to the further embodiments.

[0080] Embodiments of the present disclosure, insofar as they fall under the wording of the patent claims, thus relate, inter alia, to: A MEMS converter with an enlarged fluidic effective area consisting of an actuator (active element) and a passive element.

[0081] Embodiments in which the actuator is connected to the substrate at one side. Embodiments in which the passive element is rigidly connected at its freely oscillating end and follows the movement of the actuator.

[0082] Embodiments in which the passive element has a rigidity at least comparable to or higher than that of the actuator.

[0083] Embodiments in which the passive element is rod-shaped.

[0084] Embodiments in which the passive element has a variable thickness in plan view, which has the largest geometric dimensions at the connection point to the actuator and has the smallest geometric dimensions at the freely oscillating end.

[0085] Embodiments in which a lateral deformation of the cantilevered bending transducers occurs based on an electrical potential.

[0086] Embodiments in which the length of the passive element corresponds to 20-160% of the length of the actuator, preferably 60-100%, and particularly preferably 80%. Embodiments in which adjacent transducers in a transducer system are arranged such that they are clamped opposite one another.

[0087] Embodiments in which the actuator and passive element are enclosed in a cavity. The cavity is formed by the edge arranged in the substrate plane, as well as the lid and handling wafers. Adjacent transducers share a common edge. Transducers, each consisting of an actuator and a passive element, divide the cavity into two sub-cavities.

[0088] Embodiments in which openings in the lid and handling wafers connect the subcavities to the environment. The openings can be arranged above the common edge, so that adjacent subcavities are connected to each other.

[0089] The description and drawings only illustrate the principles of the disclosure. Furthermore, all examples provided herein are expressly intended to serve only illustrative purposes to assist the reader in understanding the principles of the disclosure and the concepts contributed by the inventors to advance the art. All statements herein regarding principles, aspects, and examples of the disclosure, as well as specific examples thereof, include their equivalents.

Claims

1. A MEMS device, comprising: a layer stack (110) having at least one second layer (112) formed between a first layer (111) and a third layer (113), wherein at least a first cavity (114) is formed in the second layer (112); a laterally deflectable element (120) having an end (121) connected to a sidewall (115) of the first cavity (114) and a free end (122), wherein the laterally deflectable element (120) is deflectable in the plane of the second layer (112); and a passive element (130) rigidly connected to the free end (122) of the laterally deflectable element (120) to follow a movement of the laterally deflectable element (120); wherein the laterally deflectable element (120) and the passive element (130) divide the first cavity (114) into a first sub-cavity (114-1) and a second sub-cavity (114-2), wherein the first sub-cavity (114-1) is in contact with an ambient fluid of the MEMS device via at least one first opening (140-1, 140-2), wherein the second sub-cavity (114-2) is in contact with the ambient fluid of the MEMS device via at least one second opening (150-1, 150-2), wherein the at least one second opening (150-1, 150-2) is formed in the first layer (111) or the third layer (113), and wherein the at least one first opening (140-1, 140-2) is formed in a different layer of the first layer (111) and the third layer (113) than the at least one second opening (150-1, 150-2).

2. The MEMS device of claim 1, wherein a stiffness of the passive element (130) is greater than or equal to a stiffness of the laterally deflectable element (120).

3. The MEMS device of claim 1 or claim 2, wherein an extension of the passive element (130) along a thickness direction of the second layer (112) is equal to an extension of the laterally deflectable element (120) along the thickness direction of the second layer (112).

4. The MEMS device of claim 1 or claim 2, wherein an extension of the passive element (130) along a thickness direction of the second layer (112) is at least partially smaller than an extension of the laterally deflectable element (120) along the thickness direction of the second layer (112).

5. The MEMS device of any one of claims 1 to 4, wherein a cross-section of the passive element (130) along its longitudinal extension is smaller than a cross-section of the laterally deflectable element (120) along its longitudinal extension.

6. The MEMS device of any one of claims 1 to 5, wherein a cross-section of the passive element (130) decreases from an end (131) of the passive element (130) connected to the laterally deflectable element towards a free end (132) of the passive element (130).

7. The MEMS device of any one of claims 1 to 6, wherein at least one cavity (133-1, ..., 133-8) is formed in the passive element (130).

8. The MEMS device of any one of claims 1 to 7, wherein a ratio of a longitudinal extension of the passive element (130) to its lateral extension is greater than 10:1.

9. The MEMS device of any one of claims 1 to 8, wherein a longitudinal extension of the passive element (130) is between 20% and 160% of a longitudinal extension of the laterally deflectable element (120).

10. The MEMS device of any one of claims 1 to 9, wherein the first cavity (114) is delimited by two further sidewalls (116, 117), wherein the laterally deflectable element (120) extends along its longitudinal extension between the two further sidewalls (116, 117), and wherein respective profiles of the further sidewalls (116, 117) are at least partially adapted to an outer contour of the laterally deflectable element (120).

11. The MEMS device of any one of claims 1 to 10, wherein a partition wall (118) is further formed in the first cavity (114), which together with the laterally deflectable element and the passive element (130) divides the first cavity (114) into the first sub-cavity (114-1) and the second sub-cavity (114-2), wherein a gap is formed between the partition wall (118) and a free end (132) of the passive element (130) to enable a movement of the passive element (130) relative to the partition wall (118).

12. The MEMS device of any one of claims 1 to 11, wherein the first sub-cavity (114-1) is in contact with the ambient fluid of the MEMS device via two first openings (140-1, 140-2), wherein one of the two first openings (140-1, 140-2) is arranged in a region of the first sub-cavity (114-1) in which the laterally deflectable element (120) extends, and wherein the other of the two first openings (140-1, 140-2) is arranged in a region of the first sub-cavity (114-1) which is different therefrom.

13. The MEMS device of any one of claims 1 to 12, wherein the laterally deflectable element (120) is configured to deform laterally upon application of a first potential, such that the laterally deflectable element (120) and the passive element (130) move with respect to sidewalls (116, 117) of the first cavity (114) in order to alternately reduce and increase a volume of the first sub-cavity (114-1) for influencing the ambient fluid, and conversely alternately increase and / or reduce a volume of the second sub-cavity (114-2).

14. The MEMS device of any one of claims 1 to 13, wherein the laterally deflectable element (120) comprises a first electrode layer and a second electrode layer between which a non-conductive layer is configured, wherein the laterally deflectable element (120) is configured to: deform laterally when a first voltage signal is applied to the first electrode layer and the second electrode layer; and / or generate a second voltage signal at the first electrode layer and the second electrode layer in case of lateral deformation due to an application of external force.

15. The MEMS device of any one of claims 1 to 14, further comprising: a second cavity (1114) formed in the second layer (112); a further laterally deflectable element (1120) having an end (1121) connected to a sidewall (1115) of the second cavity (1114) and a free end (1122); a further passive element (1130) rigidly connected to the free end (1122) of the further laterally deflectable element (1120) to follow a movement of the further laterally deflectable element (1120); wherein the further laterally deflectable element (1120) and the further passive element (1130) divide the second cavity into a third sub-cavity (1114-1) and a fourth sub-cavity (1114-2), wherein the third sub-cavity (1114-1) is in contact with the ambient fluid of the MEMS device via at least one third opening (1140-1, 1140-2), wherein the fourth sub-cavity (1114-2) is in contact with the ambient fluid of the MEMS device via at least one fourth opening (1150-1, 1150-2), and wherein the at least one third opening (1140-1, 1140-2) is formed in a different layer of the first layer (111) and the third layer (113) than the at least one fourth opening (1150-1, 1150-2).