MEMS with synchronous moving elements

Abstract

A MEMS comprises a substrate with a cavity arranged within the substrate and a plurality of movable elements arranged within the cavity. These movable elements are configured to interact with a fluid located within the cavity, with the movement of the fluid being causally related to the movement of the movable elements. The plurality of movable elements are electrically active and electrically interconnected in parallel to one another via a shared electrical conduction path to a common signal reference. The MEMS is configured to synchronize propagation delays between the common signal reference and the conduction paths of different movable elements, to synchronize the movements of the movable elements via an electrical signal provided at the signal reference, and / or to synchronize electrical signals generated by the movement of the movable elements at the location of the signal reference.

Description

The present invention relates to a MEMS with synchronous movable elements and to a method for operating a MEMS. The present invention relates in particular to MEMS with electrically synchronous fins or movable elements.In the case of MEMS for moving a fluid, for example in the case of sound generators, and in the case of MEMS for detecting or sensing a movement in a fluid, for example in the form of a microphone, there are configurations in which movable elements for moving or for being moved are electrically connected in parallel. For an advantageous operation, it is desirable to avoid distortions and deviations between the movements.WO 2021 / 144400 A1 discloses a MEMS sound transducer in which the electrodes for controlling the lamellae are connected in parallel. FIG. 11 of WO 2021 / 144400 A1 illustrates an electrical contacting, preferred there, of the MEMS loudspeaker with an oscillatory membrane based on individual piezoceramics. In FIG. 11A, a plan view is shown and in FIG. 11B, a side view of a MEMS loudspeaker is shown. Electrode pads are used to activate the individual lamellae or vertical sections in parallel, with U-shaped spacers (spacers) being present on each side of the lamellae and providing a mechanical and electrical connection to the next lamella.However, such systems have disadvantages with regard to distortions in the generated signals.Accordingly, MEMS with good signal properties in the actuator and / or sensor range would be desirable.It is therefore an object of the present invention to provide MEMS with good signal properties in the actuator and / or sensor area. This object is achieved by the subject matter of the independent claims.A core idea of the present invention is to have recognized that at least a part of a differing behavior between movable elements arises from the fact that they are connected to a common signal reference, for example a signal sink or a signal source or a collection point, and different propagation time differences are present between the signal reference and the respective movable element. According to the invention, it has been recognized that compensating or compensating for the propagation time differences in order to synchronize the movement of the movable elements or in order to synchronize the generated electrical signals at the location of the signal reference leads to good signal properties of the generated signals both during an actuator operation and during a sensor operation.According to one exemplary embodiment, a MEMS comprises a substrate having a cavity arranged in the substrate. The MEMS includes a plurality of movable elements disposed in the cavity configured to interact with a fluid disposed in the cavity, wherein a movement of the fluid and a movement of the movable elements are causally related. The plurality of movable elements is formed electrically actively and is electrically connected in parallel to one another via a respective electrical conduction path to a common signal reference. The MEMS is configured to align delay differences between the common signal reference on the one hand and the conduction paths of different movable elements on the other hand with one another, in order to synchronize movements of the movable elements generated by an electrical signal provided at the signal reference and / or in order to synchronize electrical signals generated by the movable elements by the movement at the location of the signal reference.According to an embodiment, a method for operating a MEMS having a substrate and a cavity arranged in the substrate and a plurality of movable elements arranged in the cavity and actively formed comprises moving the plurality of movable elements arranged in the cavity, such that the movable elements interact with a fluid arranged in the cavity, such that a movement of the fluid and a movement of the movable elements are causally linked. The method is carried out in such a way that the plurality of movable elements are electrically connected in parallel to one another via a respective electrical conduction path to a common signal reference. Propagation time differences between the common signal reference on the one hand and the conduction paths of different movable elements on the other hand are matched to one another in order to synchronize movements of the movable elements generated by an electrical signal provided at the signal reference and / or in order to synchronize electrical signals generated by the movable elements by the movement at the location of the signal reference.Further advantageous embodiments are the subject matter of dependent patent claims.Particularly preferred embodiments of the present invention will be explained below with reference to the accompanying drawings. The following are shown: FIG. 1 shows a schematic side sectional view of a MEMS according to an embodiment; FIG. 2 ashows a schematic top view of sections of conduction paths according to exemplary embodiments; FIG. 2 b shows a schematic illustration of an exemplary embodiment for matching the electrical impedance of conduction paths to one another; FIG. 2 cshows a schematic block diagram of a MEMS according to an embodiment, in which the signal reference of a MEMS is coupled to a signal source for providing a signal voltage; FIG. 3 shows a schematic equivalent circuit diagram of a MEMS according to an exemplary embodiment; and FIG. 4 shows a schematic flow diagram of a method according to an exemplary embodiment.Before exemplary embodiments of the present invention are explained in more detail below with reference to the drawings, it is pointed out that identical, functionally identical or identically acting elements, objects and / or structures are provided with the same reference numerals in the different figures, with the result that the description of these elements shown in different exemplary embodiments is interchangeable or can be applied to one another.Exemplary embodiments described below are described in connection with a multiplicity of details. However, embodiments may also be implemented without these detailed features. Further, embodiments will be described for convenience using block diagrams to replace a detailed diagram. Furthermore, details and / or features of individual exemplary embodiments can be easily combined with one another, provided that it is not explicitly described to the contrary.The following exemplary embodiments relate to microelectromechanical systems, MEMS, in which an actuator and / or sensor operation is provided. In the case of actuator operation, forces may be generated using electrical signals to deflect movable elements. Examples of these are described in DE 10 2017 206 766 A1 and WO 2022 / 117197 A1, which are particularly suitable for the use of the present invention, but do not restrict the invention. The said documents are incorporated in their full scope into the present patent application in this respect.Movable elements of a MEMS can move parallel to a substrate plane or wafer surface, which is also referred to as in-plane movement. Alternatively or additionally, however, movable elements can also move perpendicular thereto, i.e. out-of-plane, which can be implemented independently and combinatorially within the scope of the invention described herein.In an actuator operation, piezoelectric, electrostatic, electrodynamic, thermomechanical or other actuators, for example, can be used to convert an electrical signal into an actuating force for the movable element. Examples of actuators are, for example, pumps or sound generators or loudspeakers. In a sensory operation, for example, a force acting on the respective movable element and causing a deflection of the movable element can be converted into an electrical signal. Examples of these are, for example, microphones or pressure sensors.Since MEMS typically have small displacement paths compared to macroscopic assemblies, there is sometimes a desire to use multiple movable elements to generate corresponding signal amplitudes or effective forces. In an actuator mode, the movable elements can be connected, for example, parallel to one another and driven together. In the case of a sensory operation, the movable elements can likewise be connected in parallel to one another and evaluated together.Embodiments of the present invention relate in particular to MEMS which have actively movable elements which are connected mechanically and electrically in parallel and have different path resistances or impedances of the signal line on account of different distances from the voltage source or signal sink. This can lead to the signal voltage amplitude reaching the actively movable elements in a delayed manner in the course of an exponential function, wherein reference is to be made to an RC low-pass behavior for this purpose.The actively movable elements which have the shortest distance from the voltage source in the circuit thereby always first reach the predefined signal voltage. The other movable elements arranged further away follow the signal voltage in a time-delayed manner according to its position. The described time offset and also the deviating quality of the signal voltage during the actuation of the individual active components can cause undesired component behavior, such as reduced transduction or asynchronicity.In a sound generator such as a microspeaker, this may result in reduced deflection of individual elements and thus low sound output or phase offset, which in turn may result in undesirable artifacts and variations in sound and / or may cause device function limitation, for example, by pull-in in in electrostatic systems. For example, those actuators which are located closer to the signal voltage source can more often go into the pull-in. Due to the abruptly increasing capacitance, the voltage on the actively movable element decreases. Furthermore, the varactor also increases the delay time, which is more pronounced the greater the electrical change in capacitance of the drive due to the drive.Such effects occur in actively movable elements, for example in MEMS microspeakers, MEMS pumps, MEMS valves, MEMS varactors and / or MEMS ultrasound components. In addition to the described actuators, however, corresponding sensors can also be improved with the exemplary embodiments described herein. Embodiments enable synchronous operation of movable elements in a MEMS transducer.Embodiments overcome the disadvantage of previously known solutions, which consists in actuators connected in parallel having different line lengths or non-matched line resistances and / or line impedances to the signal source or signal sink. Actuators with the shortest line length or the smallest line resistance thus far first reach the predetermined signal voltage. According to exemplary embodiments, it is achieved that a state is at least approximated in which the same signal voltage is applied to all active elements simultaneously or the signals are obtained from all active elements simultaneously at a signal reference.Embodiments of the present invention are directed to providing a MEMS transducer having a plurality of synchronously operating elements. This reduces or prevents a delay of the signal voltage at the transducer elements and / or a delayed arrival at a signal reference and an undesired behavior, such as a pull-in, in the elements which are located closer to the signal voltage source.FIG. 1 shows a schematic side sectional view of a MEMS 10 according to an embodiment. In other embodiments of exemplary embodiments described herein, however, the discussions are also valid for a plan view of a MEMS. The MEMS 10 comprises a substrate 12 with a cavity 14 arranged in the substrate 12, The substrate 12 can be formed in one layer or in multiple layers, for example by etching out the cavity 14 and / or by connecting a plurality of wafers to one another, for example by means of a bonding process. The substrate 12 can have a semiconductor material, for example comprising monocrystalline or polycrystalline silicon, wherein other MEMS-compatible semiconductor materials can also be used without further work.Electrical connections in the substrate 12 and / or the MEMS 10 may be obtained by doping into semiconductor materials and / or by using other conductive materials, such as metal materials.The MEMS 10 comprises a plurality of movable elements 16 1 and 16 2, arranged in the cavity 14, wherein the number of movable elements can also be easily greater than 2, for example at least 3, at least 5, at least 10 or more.The movable elements 16 1 and 16 2 are configured to interact with a fluid 18 arranged in the cavity, wherein a movement of the fluid 18 and a movement 22 1 of the movable element 16 1 and a movement 22 2 of the movable element 16 2 are causally related. For example, movement of the fluid 18 may result in the movements 22 1 and 22 2 such as when the MEMS 10 is operated as a sensor. Alternatively or additionally, active generation of the movements 22 1 and 22 2, for example by means of electrical signals, can lead to a movement of the fluid 18, for example when using the MEMS 10 as an actuator, for example as a sound generator.The movable elements 16 1 and 16 2 are actively formed and are electrically connected in parallel to one another via a conduction path 24 1, 242 to a common signal reference 26. The signal reference 26 may, but not necessarily, be an active circuit for generating or providing or for receiving or evaluating electrical signals. The signal reference 26 may also include a crosspoint or junction or interface for contacting an external circuit for such purposes. The signal reference 26 may be, for example, a current source or voltage source, including or couplable to such to provide an electrical signal via the conduction path 24 1 to the movable element 16 1 and an electrical signal via the conduction path 24 2 to the movable element 16 2. The line paths 24 1 and 24 2 can optionally have a common section 28, but can also be connected directly to one another in parallel at the signal reference 26.Transit times 32 1 of the line path 24 1 and 32 2 of the line path 24 2 can be influenced by a plurality of parameters. One of the parameters is, for example, a line length, another an ohmic resistance, which in turn can be influenced by the line length, but also by a line cross section. A further parameter is capacitive couplings, which can also result from a periphery of the respective conduction path 24 1 and / or 24 2. The MEMS 10 is configured to align the propagation time differences 32 1 between the signal reference 26 and the movable element 16 1 on the one hand and between the signal reference 26 and the movable element 16 2 to one another. In other words, measures can be taken in the MEMS 10 in order to align the propagation times 32 1 and 32 2 to one another and thus keep propagation time differences between the propagation times 32 1 and 32 2 low. During an actuator operation, it can thereby be achieved that an electrical signal provided at the signal reference 26 is synchronized for generating the movements 22 1 and 22 2 of the movable elements 16 1 and 16 2. In an alternatively or additionally implemented sensory operation, it can be achieved by the movable elements 16 1 and 16 2 being moved by the movement 22 1 or. 22 2 generated electrical signals at the location of the signal reference 26.The movements 22 1 and 22 2 can be arranged in the same direction or along spatial directions different from one another, wherein in particular a parallel alignment of the movements 22 1 and 22 2 is advantageous. The movements 22 1 and 22 2 can be arranged in-plane and / or out-of-plane. Further, the cavity 14 may, but not necessarily, be sealed from an environment of the substrate 12. Embodiments provide that openings in the substrate 12 connect the cavity 14 to the environment and the fluid 18 can flow through such openings into the cavity 14 and / or out of the cavity 14.According to exemplary embodiments, the movable elements are arranged in the MEMS at a distance 34 that is different from one another 1, 342 to the signal reference 26. This can result, for example, from the fact that the signal reference 26 is arranged at a specific location in the MEMS 10 or can be connected to the MEMS 10 at a specific location, for example in a case in which the signal reference 26 comprises an external circuit which can be coupled to the MEMS 10. Movable elements 16 1 and 16 2 positioned at different locations in the MEMS 10 may be at a different distance from one another at this location. In known circuits, this can lead to the use of line paths 24 1 and 24 2 with different runtimes 32 1 and 32 2 which is addressed with embodiments described herein, however. To this end, exemplary embodiments provide different possibilities which can be used individually, but also in combination with one another.Thus, embodiments provide that the conduction paths 24 1 and 24 2 have a substantially identical electrical connection characteristic of the movable elements 16 1 and 16 2 to the signal reference 26. Such a connection characteristic can mean or comprise, for example, an electrical conductivity and / or an electrical impedance, that is to say the conduction paths 24 1 and / or 24 2 can be formed in such a way that a connection characteristic which substantially or as precisely as possible corresponds is present, for example an approximately identical electrical conductivity and / or an approximately identical electrical impedance. Deviations from an exact correspondence are possible without problems within the scope of exemplary embodiments described herein, for example within a tolerance range of ±20%, ±10% or ±5%, preferably less.Compared to a theoretical initial state, in which the movable elements 16 1 and 16 2 are at a distance from the signal reference 26 that is different from one another, at least one of the line paths 24 1 and 24 2 can be modified. Thus, for adapting the electrical connection characteristic, at least one of a path-specific meandering of a course of at least one of the path lines can be provided. Alternatively or additionally, a line path-specific cross-sectional change can be provided. This can relate over the entire conduction path or else only to sections. Thus, a local reduction of the line cross section can generate a local increase of a line capacitance and / or a line path resistance. Alternatively or additionally, one of the line paths 24 1 or 24 2 can be provided with a smaller or increased line cross section compared to the other line path. Alternatively or additionally to these measures, the conduction paths for adapting the electrical connection characteristic can comprise a capacitive coupling, specific to the conduction path, between the conduction path and the substrate. Such a coupling can exist, for example, to adjacent layers or wafers, for example to a cover wafer and / or bottom wafer, which can delimit a cavity 14 provided in a device wafer.According to exemplary embodiments, the conduction paths 24 1 and 24 2 can be designed such that they have a substantially identical electrical conductivity. This can be achieved, for example, by configuring shorter conduction paths with a larger cross section than longer conduction paths. Alternatively or additionally, this can also be achieved by extending line paths for movable elements, which are arranged closer to the signal reference 26, for example the line path 24 1, by additional line lengths, so that the line paths 24 1 and 24 2 have an adjusted line length. This may possibly be at least approximately the same, which is not necessary in view of other measures, for example additional line cross-sectional changes or the like, since the measures are individually, but also in combination, directed towards matching the transit time differences 32 1 and 32 2 to one another.According to an embodiment, the movable elements 16 1 and 16 2 have a different distance from the signal reference 26 from each other, but at the same time have a substantially equal line length.FIG. 2 ashows a schematic top view of sections of the conduction paths 24 1 and 24 2, as can be used in the MEMS 10, for example. Referring to FIG. 1, movable element 16 1, which is connected to conductive path 24 1 with signal reference 26, is disposed at a shorter distance 34 1 than movable element 16 2, which is disposed at distance 34 2. The conduction path 24 1 may include an additional conduction path portion 36 to align a length of the conduction paths 24 1 and 24 2 with each other. The additional distance 36 can preferably be arranged in a meandering manner, since inductances can be kept low as a result. Additional portions 36 may be provided in 1 at one or more locations along the conduction path 24. This does not exclude additional sections 36 in 2 also in the line path 24. It is also to be noted here that, within the scope of exemplary embodiments described herein, it is assumed for the sake of simplicity that the conduction paths of movable elements arranged closer to the signal reference 26 are extended in order to achieve an adaptation of the conduction path lengths. However, due to layout-specific conditions in the MEMS 10, it may also be the case that movable elements arranged closer to the signal reference 26 are to be connected to the signal reference 26 via a comparatively longer line path length, so that an adaptation can then take place for the line path which, although having a shorter direct distance, has a longer line length.According to an embodiment, the movable elements 16 1 and 16 may be arranged 2 with a different distance 34 1 and 34 2 to the signal reference 26 in the MEMS 10. However, the conduction paths 24 1 and 24 2 may have a substantially equal conduction length, such as within a tolerance range of ±20%, ±10%, ±5%, or less. The conduction paths 24 1 and 24 2 may both have a respective potentially meandered conduction path portion, wherein the different additional and potentially meandered conduction path portions have a first electrical impedance and a second electrical impedance, respectively, wherein a total obtained impedance of the first conduction path 24 1 and a total obtained electrical impedance of the second conduction path 24 2 substantially match due to the additional conduction path portions. This means that a sum impedance of the actual line path length and additional sections leads to a substantially matching line path impedance within the tolerances mentioned, wherein additional sections are optional for this purpose and possibly are provided only for those line paths which are significantly shorter than other line paths, so that also at least one of the line paths can remain in the MEMS 10 without additional sections.This means that the impedance matching by means of meandering can be designed differently in different line path sections, but that the remaining path sections likewise have an impedance that differs from one another on account of the different length, such that the sum of the impedances of meandering and remaining path length can overall coincide with the other line paths.According to exemplary embodiments, it can be provided that the electrical conduction paths have a substantially identical electrical impedance. According to one embodiment hereof, in the case of different conduction paths for adjusting the electrical impedance, a path-specific change in cross section of at least one conduction path and / or a path-specific meandered conductor track section can be provided.FIG. 2 b shows one possibility of matching the electrical impedance of the line paths 24 1 and 24 2 to one another. For example, movable element 16 arranged relatively closer may be connected in 1 to signal reference 26 via conduction path 24 1 having a width 38 1 while movable element 16 arranged relatively farther may be connected in 2 to signal reference 26 via conduction path 24 2 having a width 38 2. This can be suitable in particular for MEMS structures in which a layer thickness of electrical tracks in a MEMS wafer is configured identically. Alternatively or additionally, the width 38 1 and 38 2 can also relate to a different spatial direction, for example to a layer thickness, combinations of which are likewise possible. Each of the spatial directions makes it possible individually, but also in combination with another spatial direction, to set a line path cross section.In addition to a path-specific cross-section change or a path-specific line cross-section, a path-specific meandered conductor track section can be arranged, as described. Different additional conduction path portions may differ from one another in terms of a number of meanders, a length of the meanders and / or a shape or spatial density of the meanders. Alternatively or additionally, a path-specific capacitive coupling to the substrate can also be arranged in order to obtain a substantially identical electrical impedance between different conduction paths.FIG. 2 cshows a schematic block diagram of a MEMS 20 according to an embodiment, in which the signal reference 26 is coupled to a signal source 42 for providing a signal voltage 44. The signal source 42 may be part of the MEMS 20 or may be provided as an external component. A connection characteristic 46 1 of the line path 24 1 can be at least approximately matched to a connection characteristic 46 2 of the line path 24 2 by arranging the section 36 in the line path 24 1.In other words, FIG. 2 cshows a system with the same drive characteristic for the electrodes, movable elements 16 to be connected in parallel 1, 162.FIG. 3 shows a schematic equivalent circuit diagram of a MEMS 30 according to an exemplary embodiment. The MEMS 30 has, by way of example, a signal source 42 which can provide the signal reference 26 of the MEMS 10 or is at least coupled thereto. In other words, the signal reference 26 of the MEMS 10 may be configured to couple to a signal source, such as the signal source 42, for driving the movable elements 16 1 to 16 3. The movable elements 16 1 to 16 3 can be connected in parallel to one another, so that a respective track resistance R 1, R 2 forms at least a part of a total track resistance of a subsequent line path 24 2 or. 24 may have 3. Thus, for example, the conduction path 24 2 can comprise the resistors R1 and R2 and the conduction path 24 3 can additionally also comprise the track resistor R3. It is also shown that different capacitive couplings C 1, C 2 and C 3 can be effective for different movable elements 16 1, 162 and 16 3 wherein in particular the capacitances C 1 to C 3 can cause effects which are dependent on a signal voltage 44 of the signal source 42, for example a frequency thereof. It will be appreciated that by providing the measures described herein, individually or in combination, an adjustment of the behaviours of the movable elements 16 1 to 16 3 can be effected, which is advantageous.According to an exemplary embodiment and with reference to a layered construction of MEMS described herein, a respective conduction path can have a capacitive coupling to at least one layer of the substrate 12, which contributes to an impedance specific to the conduction path. The capacitive couplings may be individually adapted to match an acting impedance in different conduction paths to each other. This can be implemented, for example, by applying conductor tracks, possibly of the same length and / or of the same cross section, and arranging them on differently designed insulators or dielectric layers, which can have dielectric constants that differ from one another. As a result, a different capacitive coupling to the substrate can be obtained. The capacitive coupling can alternatively or additionally also be adjusted by a different shape from one another, for example a size of an area which becomes capacitive. This does not exclude combinatorial measures with regard to the conductor track cross section and / or possible meanderings.According to one exemplary embodiment, a MEMS described herein, such as the MEMS 10 and / or 30, is formed as a sensor or as an actuator. Suitable possible actuators are sound generators which can be operated, for example, in infrasonics, in the acoustic range and / or in the ultrasonic range, for example as loudspeakers. The movable elements 16 can be configured for synchronized generation of a sound wave in the fluid.In other words, FIG. 3 shows a MEMS transducer with electrodes connected in parallel, in fact in series. The state shown here can be readily applied to elements according to exemplary embodiments which are actually connected in parallel.FIG. 4 shows a schematic flow diagram of a method 400 according to an exemplary embodiment. A step 410 includes moving the plurality of movable elements of a MEMS disposed in the cavity such that the movable elements interact with a fluid disposed in the cavity such that a movement of the fluid and a movement of the movable elements are causally related.Features 420 of the method 400 have the effect that the same is carried out in such a way that the plurality of movable elements are electrically connected to a common signal reference in parallel with one another via a respective electrical conduction path. The method is carried out in such a way that propagation time differences between the common signal reference on the one hand and the conduction paths of different movable elements on the other hand are matched to one another in order to synchronize movements of the movable elements generated by an electrical signal provided at the signal reference and / or in order to synchronize electrical signals generated by the movable elements by the movement at the location of the signal reference. The adaptation can be provided both within the MEMS, but can also be implemented, for example, via an additional interconnection of a signal source or signal sink to be externally coupled to the MEMS.Embodiments of the present invention achieve the object of providing signals with high quality, inter alia by a parallel circuit of the MEMS transducer elements, movable elements, each having the same electrical connection characteristic, such as line lengths or the like, to the energy source or energy sink. If necessary, the tracks to be conducted to the active elements are geometrically targeted to balance out according to their conductivity, this also including the parasitic impedance.Exemplary embodiments of the present invention relate to MEMS in which a multi-element MEMS transducer structure can be characterized, in which all active elements of the transducer are electrically connected to one another in such a way that the terminals of the individual elements with the same name are connected to a pole of the signal source via the same line lengths or impedances. In this case, the same name is understood to mean an interconnection with the same potential.According to some embodiments, the impedance over the line length is adjusted by a meander. According to alternative or additional configurations, the impedance is adjusted by a change in cross section, which can be implemented by means of an etching from above or from below, for example as a "draw-in". According to further exemplary embodiments, which can be used alternatively or additionally, the impedance can also be introduced as a capacitive load by the connection to the cover wafer.Although some aspects have been described in connection with a device, it is understood that these aspects also represent a description of the corresponding method, so that a block or a component of a device is also to be understood as a corresponding method step or as a feature of a method step. Analogously, aspects described in connection with or as a method step also represent a description of a corresponding block or detail or feature of a corresponding device.The above-described embodiments are merely illustrative of the principles of the present invention. It is to be understood that modifications and variations of the arrangements and details described herein will be apparent to others skilled in the art. Therefore, it is intended that the invention be limited only by the scope of the following claims and not by the specific details presented herein by way of description and explanation of the embodiments.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedWO 2021 / 144400 A1

[0003] DE 10 2017 206 766 A1

[0014] WO 2022 / 117197 A1

[0014]

Claims

A MEMS comprising: a substrate (12) having a cavity (14) arranged in the substrate (12); a plurality of movable elements (16 1-163), arranged in the cavity (14), which are configured to interact with a fluid (18) arranged in the cavity (14), wherein a movement of the fluid (18) and a movement (22) of the movable elements (16 1-163) are causally connected; wherein the plurality of movable elements (16 1-163) are electrically actively formed; and are electrically connected to a common signal reference (26) via a respective electrical conduction path (24) in parallel with one another; wherein the MEMS is configured to align delay differences between the common signal reference (26) on the one hand and the conduction paths (24) of different movable elements on the other hand with one another, in order to synchronize movements (22) of the movable elements (16 1-163) generated by an electrical signal provided at the signal reference (26); and / or in order to synchronize electrical signals generated by the movable elements (16 1-163) by the movement (22) at the location of the signal reference (26).MEMS according to one of the preceding claims, wherein the movable elements (16 are arranged in the MEMS in 1-163) at a distance (34) from one another from the signal reference (26).The MEMS of claim 1 or 2, wherein the conduction paths (24) have a substantially equal electrical connection characteristic of the movable elements (16 1-163) to the signal reference (26).The MEMS of claim 3, wherein the electrical connection characteristic comprises an electrical conductivity and / or an electrical impedance.MEMS according to Claim 3 or 4, in which the conduction paths (24) for adapting the electrical connection characteristic of at least one of a path-specific meandering of a course of conduction paths (24); a path-specific change in cross section; and a path-specific capacitive coupling between the conduction path (24) and the substrate (12).MEMS according to one of the preceding claims, wherein the conduction paths (24) have a substantially identical electrical conductivity.A MEMS according to any preceding claim, wherein the movable elements (16 are arranged in the MEMS 1-163) at a different distance (34) from the signal reference (26); and the conduction paths (24) have a substantially equal conduction length.The MEMS of claim 7, wherein a conductive path of the first movable element (16 1), which is arranged opposite a second movable element (16 2) at a lesser distance (34) from the signal reference (26), comprises an additional and meandered line path section (36) to adjust a length of the line paths (24).A MEMS according to any preceding claim, wherein the movable elements (16 1-163) are arranged in the MEMS at a different distance (34) from the signal reference (26); and the conduction paths (24) have a substantially equal conduction length; wherein at least a first conduction path (24 1) has a first meandered conduction portion and a second conduction path (24 2) has a second meandered conduction portion; wherein the first meandered conduction path section has a first electrical impedance and the second meandered conduction path section has a different second electrical impedance, and a sum impedance of the first conduction path (24 1) and a sum impedance of the second conduction path (24 2) substantially match.MEMS according to one of the preceding claims, wherein the electrical conduction paths (24) have a substantially equal electrical impedance.MEMS according to Claim 10, in which different conduction paths (24) for adjusting the electrical impedance have a path-specific change in cross section of at least one conduction path (24) and / or a path-specific meandered conductor track section and / or a path-specific capacitive coupling to the substrate (12).MEMS according to one of the preceding claims, wherein a respective conduction path (24) has a capacitive coupling to at least one layer of the substrate (12), which contributes to an impedance specific to the conduction path; wherein the capacitive couplings are individually adapted to match an acting impedance in different conduction paths (24).MEMS according to one of the preceding claims, wherein the signal reference (26) is configured for coupling to a signal source (42) for driving the movable elements (16 1-163).The MEMS of claim 13, comprising the signal source (42).The MEMS according to claim 13 or 14, configured as a sonic transducer; wherein the movable elements (16 1-163) are configured for synchronized generation of a sound wave in the fluid (18).A method (400) of operating a MEMS having a substrate; having a cavity arranged in the substrate and having a plurality of movable elements arranged in the cavity and actively formed; the method comprising: moving (410) the plurality of movable elements arranged in the cavity such that the movable elements interact with a fluid arranged in the cavity such that a movement of the fluid and a movement of the movable elements are causally related; such that the plurality of movable elements are electrically connected in parallel to one another via a respective electrical conduction path to a common signal reference; and such that delay differences between the common signal reference on the one hand and the conduction paths of different movable elements on the other hand are matched to one another in order to synchronize movements of the movable elements generated by an electrical signal provided at the signal reference; and / or in order to synchronize electrical signals generated by the movable elements by the movement at the location of the signal reference.

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