MEMS with overlay drive and method of operation thereof

Abstract

A MEMS device includes a layer stack having a plurality of MEMS layers arranged along a layer stack direction. The MEMS device includes a movable component formed in a first MEMS layer and arranged between a second MEMS layer and a third MEMS layer of the layer stack. Further provided is a drive unit including a first drive structure mechanically fixedly connected to the movable component and a second drive structure mechanically fixedly connected to the second MEMS layer. The drive unit is configured to generate a drive force on the movable component perpendicular to the layer stack direction, and the drive force is configured to deflect the movable component.

Description

Technical Field

[0001] This invention relates to a MEMS device and a method of operating the same. More specifically, this invention relates to a MEMS having overlay actuation for driving movable components in a plane. Background Technology

[0002] MEMS transducers are known to be formed from substrates and have finite geometric dimensions or aspect ratios due to limited aspect ratios (e.g., the Bosch method). Increasing the volume of a MEMS device can be achieved, for example, through deeper etching. However, simultaneously, it is impossible to achieve small electrode spacing between adjacent electrodes, as this spacing also increases due to the etching method. Therefore, it is at least difficult to develop a transducer that, on the one hand, can interact with a large amount of surrounding fluid, and on the other hand, can apply the necessary force or include a correspondingly small electrode distance.

[0003] Therefore, MEMS transducers with a large aspect ratio are needed to enable the movement of large fluid volumes while achieving small electrode spacing. Summary of the Invention

[0004] Therefore, the objective of this invention is to provide a MEMS device with a high aspect ratio.

[0005] This objective is addressed by the subject matter of the independent claims.

[0006] The core idea of ​​this invention is that it has been recognized that in-plane actuation of movable components can also be based on an electrode arrangement perpendicular to the direction of movement. This allows for the extraction of large movable components, for example by means of etching, while simultaneously allowing for small gap distances perpendicular to the direction of movement, since such gap distances are independent of the etching process used.

[0007] According to one embodiment, a MEMS device includes a layer stack having a plurality of MEMS layers arranged along a layer stack direction. Additionally, a movable component is provided formed in a first MEMS layer and arranged between a second and a third MEMS layer of the layer stack. The MEMS device includes a driving unit having a first driving structure mechanically fixedly connected to the movable component and a second driving structure mechanically fixedly connected to the second MEMS layer, allowing a force to be applied between the two driving structures. The driving unit is configured to generate a driving force perpendicular to the layer stack direction on the movable component, wherein the driving force is configured to deflect the movable component, specifically utilizing a component perpendicular to the layer stack direction, the deflection may include rotational movement, torsional movement, and / or translational movement.

[0008] According to one embodiment, the first drive structure and the second drive structure are spaced apart by a gap and arranged opposite to each other. The size of the gap along the stacking direction is adjusted by, for example, a bonding process. The bonding process allows for a small gap distance, enabling the generation of a large force, for example, using electrostatic or electric driving force.

[0009] According to one embodiment, the movable component is configured such that it comprises multiple layers joined by a bonding process. This allows for a large movable component and thus a high aspect ratio, enabling the movement of large quantities of fluid via the movable component.

[0010] According to one embodiment, the second driving structure is a structured electrode structure having at least one first electrode assembly and a second electrode assembly electrically insulated therefrom. The MEMS device is configured to apply a first potential to the first electrode assembly and a different second potential to the second electrode assembly. The MEMS device is further configured to apply a third potential to the first driving structure to generate a driving force in cooperation with the first or second potential. For example, in terms of reciprocating movement, this allows for bidirectional and potentially linear deflection of the movable component, which is advantageous.

[0011] According to one embodiment, the first electrode assembly and the second electrode assembly are electrically insulated from each other by an electrode gap. In the rest position of the movable assembly, the movable assembly is arranged symmetrically and / or asymmetrically opposite to the electrode gap. While a symmetrical arrangement at least partially enables deflection and / or symmetrical deflection already at low voltage, a preferred orientation and / or mechanical pre-deflection can be implemented by means of a symmetrical arrangement at least partially.

[0012] According to one embodiment, the electrodes of the second drive structure have a constant or variable lateral dimension perpendicular to the axial direction along an axial path perpendicular to the layer stacking direction. In other words, the electrodes can be provided as strips, for example, with variable strip widths. Variable expansion allows for taking into account and / or compensating for mechanical stresses that may be induced by electrode deformation.

[0013] According to one embodiment, the driving unit includes a third driving structure mechanically fixedly connected to a third MEMS layer. A first gap is disposed between the first driving structure and the second driving structure, and a second gap is disposed between the first driving structure and the third driving structure. The driving unit is configured to provide a driving force based on a first interaction between the first and second driving structures and based on a second interaction between the first and third driving structures. This allows the force deflecting the movable part to be further increased and / or allows the movable part to move precisely.

[0014] According to one embodiment, the drive unit is configured to generate a first driving force component based on a first interaction and a second driving force component based on a second interaction. The MEMS device is configured to generate the first driving force component or interaction and the second driving force component or interaction that are in phase or have a phase shift. While in-phase control can be used, for example, for translational displacement of a movable component, a variable but also potentially constant phase shift can be used for rotation, tilting, or torsion of a movable component.

[0015] According to one embodiment, a movable component is mechanically connected to a third MEMS layer via an elastic region. The movable component is configured to perform rotational movement based on a driving force while deforming the elastic region. This allows for the specific implementation of individual components.

[0016] According to one embodiment, the electrode structure is arranged on the side facing the second MEMS layer and / or facing the third MEMS layer, or on the MEMS layer, and forms at least a portion of the first driving structure. This enables the electrical variability of the electrical control to have high variability.

[0017] According to one embodiment, the movable component is disposed on the side facing the second MEMS layer and / or the second MEMS layer is disposed on the side facing the movable component, such that surface texture is provided to locally change the distance between the movable component and the second MEMS layer. This allows for precise adjustment of the electrostatic force based on the variable electrode spacing during movement.

[0018] According to one embodiment, the electrodes of the first driving structure and / or the electrodes of the second driving structure are arranged and interconnected in an interdigitated manner. This enables the realization of a low-level electrical interference field.

[0019] According to one embodiment, the MEMS device includes a plurality of movable components arranged side-by-side in a common MEMS plane and fluidly coupled to each other and / or coupled by means of coupling components. This allows for high fluid mobility.

[0020] According to one embodiment, a drive structure having at least two connected electrodes arranged side-by-side is disposed on each of the movable components. One of the at least two connected electrodes is connected to a first potential, and the second electrode of the at least two connected electrodes is connected to a different second potential. Opposing electrodes of adjacent movable components are connected to a combination of the first and second potentials. In other words, the electrodes of adjacent movable components can be electrically controlled in different ways. This enables individual components to be controlled as needed.

[0021] According to one embodiment, the movable component is movably arranged within a MEMS cavity. By means of the movement of the movable component, the size of at least one sub-cavity of the cavity alternately expands and shrinks, wherein the sub-cavity locally extends into a second MEMS layer. Because the sub-cavities extend into the second MEMS layer, the corresponding MEMS space can be used efficiently.

[0022] According to one embodiment, the movable component includes a component length extending along an axial direction perpendicular to the layer stacking direction. The electrodes of the first drive structure include multiple electrode segments along the component length. Adjacent electrode segments are electrically connected to each other by an electrical conductor. Along the direction perpendicular to the component length, the electrical conductor has lower mechanical stiffness than the electrode segments. Therefore, these regions can absorb deformation energy, resulting in less deformation of the electrode segments and high efficiency.

[0023] According to one embodiment, the movable component is configured to provide interaction with a fluid. This can be achieved directly through direct contact with the fluid, or indirectly through the movement of a mechanical component that provides fluid interaction via the movable component.

[0024] According to one embodiment, the driving unit includes a fourth driving structure disposed on the side of the second MEMS layer opposite to one of the movable components. Other movable components are disposed adjacent to the fourth driving structure and form a stacked arrangement with the movable components. This allows for a high degree of fluid interaction while using very little chip area due to the stacked arrangement.

[0025] According to one embodiment, a method of operating a MEMS device includes: controlling two drive structures arranged along a layer stack direction, wherein a plurality of MEMS layers of the MEMS device are arranged along the layer stack direction; and controlling the generation of a drive force perpendicular to the layer stack direction at a movable component of the MEMS device to deflect the MEMS device.

[0026] According to one embodiment, the method is configured such that the symmetrical and / or linear deflection of a movable component is controlled by means of adjacent electrode components of a drive device by controlling the electrode components symmetrically with respect to a reference potential over a time average relative to the applied potential, the electrode components being electrically insulated from each other by electrode gaps.

[0027] According to one embodiment, the deflection of the movable component is controlled asymmetrically over time along the actuation direction relative to the opposite direction; that is, it is asymmetrically controlled. For example, this can be used to compensate for mechanical pre-steering or mechanical asymmetry.

[0028] Other advantageous embodiments are the subject of the other dependent claims. Attached Figure Description

[0029] The following explanation of particularly preferred embodiments of the invention refers to the accompanying drawings, in which:

[0030] Figure 1 A schematic side cross-sectional view of a MEMS device according to an embodiment is shown;

[0031] Figure 2a A schematic side cross-sectional view of a section of a MEMS device according to an embodiment is shown;

[0032] Figures 2b to 2d illustrate the embodiments. Figure 2a Schematic side cross-sectional view of a MEMS device in different deflection states;

[0033] Figure 3a A schematic side cross-sectional view of a MEMS device according to an embodiment is shown, the MEMS device including configurations in a bottom wafer and / or a cover wafer (or top wafer);

[0034] Figures 3b to 3d A schematic side cross-sectional view of a movable component according to an embodiment is shown;

[0035] Figure 4a shows a schematic side cross-sectional view of a movable component with an electrode structure according to an embodiment;

[0036] Figure 4b shows a schematic side cross-sectional view of a movable component with a structured electrode structure according to an embodiment;

[0037] Figure 5a A schematic top view of a portion of a MEMS device illustrating the interdigitated interconnects of electrodes, according to an embodiment;

[0038] Figure 5b A schematic top view of a portion of a MEMS device illustrating the interdigitated interconnects of structured electrodes, according to an embodiment;

[0039] Figure 6 A schematic side cross-sectional view of a portion of a MEMS device according to an embodiment, including four movable components according to an embodiment;

[0040] Figures 7a to 7c A schematic side cross-sectional view showing different implementations of a MEMS device and its electrical contacts according to embodiments;

[0041] Figures 8a to 8c A side cross-sectional view of a MEMS-based acoustic transducer in three deflection states, according to an embodiment;

[0042] Figure 9 A schematic perspective view showing a portion of a MEMS device having movable components clamped on both sides, according to an embodiment;

[0043] Figure 10 A schematic perspective view showing a portion of a MEMS device having a movable component clamped on one side, according to an embodiment;

[0044] Figure 11 A schematic perspective view showing a portion of a MEMS device according to an embodiment, which may have both pores and interdigitated electrodes;

[0045] Figures 12a to 12c A top view showing an area of ​​an alternative embodiment of the basic cell of a MEMS device according to an embodiment;

[0046] Figure 13 A schematic side cross-sectional view of a portion of a MEMS device according to an embodiment is shown, wherein the movable component is formed in an H-shape;

[0047] Figure 14 A schematic side cross-sectional view of a MEMS device according to an embodiment is shown, wherein the movable components are formed in a block shape;

[0048] Figures 15a to 15c A schematic side cross-sectional view of a stacked MEMS according to an embodiment is shown;

[0049] Figures 16a to 16c Side cross-sectional views of alternative drives with linear deflection behavior based on coverage drive according to embodiments are shown in various conditions.

[0050] Figures 17a to 17c Demonstrating the relative to the embodiments Figures 16a to 16c Complementary substitution-driven implementation schemes;

[0051] Figure 18a A schematic top view of a MEMS device according to an embodiment is shown, the MEMS device being connected to a substrate opposite to the drive structure via an elastic region;

[0052] Figure 18b exhibit Figure 18a A schematic side view of the MEMS device; and

[0053] Figure 19 A schematic flowchart illustrating a method according to an embodiment described herein. Detailed Implementation

[0054] Before explaining embodiments of the invention in detail below with reference to the accompanying drawings, it should be noted that the same components, objects and / or structures having the same function or operating in the same manner have the same reference numerals in different figures, such that the descriptions of such components shown in different embodiments are interchangeable or applicable to each other.

[0055] The embodiments described below are described in the context of a number of detailed features. However, embodiments may be implemented without such detailed features. Furthermore, for clarity, block diagrams are used instead of detailed representations to describe embodiments. Moreover, the details and / or features of the various embodiments can be readily combined with each other, unless explicitly described to the contrary.

[0056] The embodiments described herein relate to microelectromechanical devices (MEMS devices). Such MEMS devices can be multilayered structures. For example, such MEMS can be obtained by processing wafer-level semiconductor materials, which may include combining multiple wafers and / or depositing layers on a wafer plane. Some embodiments described herein relate to MEMS planes. MEMS planes should be understood to be not necessarily two-dimensional and / or non-curved planes that are generally parallel to the extended surface of the processed wafer, such as planes parallel to the main surface of the wafer or subsequently the MEMS.

[0057] The embodiments described herein relate to a layer stack having multiple layers. However, the layers described herein may not necessarily be a single layer, but may readily include two, three, or more than three layers in embodiments and can be understood as a layer stack. Thus, layers from which movable components are formed can be formed in multiple layers, and layers in which movable components are disposed can be configured, for example, at least a portion of a wafer and can have multiple material layers, for example, for implementing physical, chemical, and / or electrical functions.

[0058] A planar direction can be understood as a direction within a plane, and can also be referred to by the term "in-plane". Alternatively or additionally, the direction along which layers alternate or are arranged in a layer stack can be called the layer stack direction. In this regard, a planar direction (in-plane) can refer to a direction perpendicular to it.

[0059] Some embodiments described herein are described in connection with the speaker configuration or speaker function of the corresponding MEMS device. It should be understood that, in addition to alternative or additional functions for sensory evaluation of the MEMS device or the movement or position of its movable components, such explanations can also be extended to the microphone configuration or microphone function of the MEMS device, making such microphones constitute other embodiments of the invention without limitation. Furthermore, other application areas of MEMS within the scope of the embodiments described herein include micropumps, ultrasonic transducers, or other MEMS-based applications related to moving fluids. For example, among other things, embodiments may involve the movement of actuators capable of interacting with fluids.

[0060] The embodiments involve applying an electrostatic force to displace a movable component. However, other driving principles, such as electromagnetic force generation or sensing, can be readily used to implement the described embodiments. The deflectable component may be an electrostatic, piezoelectric, and / or thermomechanical electrode that provides deformation based on an applied potential, for example.

[0061] Figure 1 A schematic side cross-sectional view of a MEMS device 10 according to an embodiment is shown. The MEMS device includes a layer stack 12, which may include multiple layers 121, 122, wherein an optional additional layer 123 and possible additional layers are part of the layer stack 12. Some layer stacks (or sequences) may be mechanically connected to each other, but spacing may also be provided in areas between adjacent layers. Furthermore, some layers in the layer stack 12 may be partially spaced apart, as shown with respect to MEMS layer 121. Here, layer 121, arranged along the layer stack direction 14 with layers 122 and 123, may be partially removed to expose a movable component 16, such that the movable component 16 can move at least relative to layer 122. Here, at least one component of the movement is perpendicular to the layer stack direction 14 along a planar direction 18 (i.e., in a plane). As will be explained in the context of the embodiment, this may include translational movement along the planar direction 18 and / or rotational components such as for torsional movement.

[0062] Movable component 16 is arranged between layers 122 and 123, wherein a drive unit 22 (or drive device) is provided to generate a driving force F on movable component 16 along a planar direction 18, the driving force F being adapted to deflect movable component 16. In some embodiments, the force F may be generated and is nearly perpendicular to the layer stack direction, but other directions are possible, for example, for torsional movement.

[0063] The driving unit includes a driving structure 22a mechanically fixedly connected to a movable component. Additionally, the driving unit 22 includes a driving structure 22b mechanically fixedly connected to the MEMS layer 122. In the context of the embodiments described herein, "mechanically fixedly connected" should be understood to mean mechanically fixing one component to another component, for example by means of fixing, such as by bonding, by joining, coating, soldering, or similar methods. Alternatively or additionally, for example, a conductive layer may be disposed on another layer to mechanically fix at least a portion of the driving structure to the layer. Alternatively or additionally, "mechanically fixedly connected" is also understood to mean, for example, that the conductive structure is part of another structure. For example, in a preferred embodiment, doping a semiconductor material can make it conductive, for example, to provide the function of an electrode. This electrode is also understood to be mechanically fixedly connected to the corresponding component, even if, from another viewpoint, the electrode and the component are the same component.

[0064] According to one embodiment, for example, the movable component 16 is configured to be conductive, such as by comprising a conductive material, such as a metallic material and / or a doped semiconductor material. Alternatively or additionally, the drive structure 22a may be disposed on the substrate of the movable component 16, for example, in the form of an electrode structure. In a similar manner, for example, the drive structure 22b may comprise a conductive material, for example, in the form of regionally doping at least the semiconductor material of layer 122 and / or by arranging an electrode structure.

[0065] The MEMS device 10 is configured such that movement of the movable component 16 occurs in a plane and the drive structure is arranged along the layer stack direction 14. This allows for a relatively large dimension 24 of the movable component 16 along the layer stack direction 14, which is, for example, at least 75 μm, at least 100 μm, at least 500 μm, or greater. A relatively large area can be exposed along the planar direction 18, which is consistent with the aspect ratio of known exposure methods such as the Bosch method. In this way, the drive structure 22 can have a gap 26 between the drive components 22a and 22b, independent of this exposure method. That is, the drive structures 22a and 22b can be spaced apart and opposite each other, for example, during the rest position of the movable component 16. The dimension of the gap 26 along the layer stack direction 14 can be adjusted by the bonding process.

[0066] For example, the size of gap 26 can be determined at least in part by bonding the layer stack along the layer stack direction 14, which allows for a relatively small size of gap 26, such as 10 μm or less, 5 μm or less, or 1 μm or less, compared to processes such as etching. The corresponding aspect ratio of size 24 can be correspondingly higher than that of gap 26, which is advantageous for the MEMS device 10 because it can interact with a large amount of fluid.

[0067] In this regard, the movable component 16 can be formed as a single layer or multiple layers. For example, the movable component 16 can have multiple layers, such as at least two layers, at least three layers, at least four layers, at least five layers, or more layers bonded together by a bonding process. For example, as part of the bonding process of a silicon wafer, different silicon layers can be bonded together to obtain a high overall layer thickness or a large size 24, thereby, for example, establishing a low dependence on or even independence from the aspect ratio of etching processes such as the Bosch etching process.

[0068] Figure 2aA schematic side view of a segment of the MEMS device 20 according to an embodiment is shown. The drive structure 22b of the drive unit is, for example, a structured electrode structure and includes at least one electrode assembly 22b1 and one electrode assembly 22b2. These electrode assemblies are electrically insulated from each other such that a first potential can be applied to electrode assembly 22b1 and a second potential different from the first potential can be applied to electrode assembly 22b2. This application includes, for example, alternately applying potentials with the same or different amplitudes to electrode assemblies 22b1 and 22b2, but it can also mean simultaneously applying the same or different potentials to electrode assemblies 22b1 and 22b2, depending on what kind of control is desired or required for the MEMS device 20.

[0069] For electrical insulation, gaps 281 to 284 can be provided between the electrode segments, and these gaps can be optionally filled with electrical insulating material or dielectric material.

[0070] MEMS device 20 may include one or more movable components 161 and 162 arranged side by side along a planar direction 18, and optionally include other movable components. Figure 1 The described drive structure 22a may be one, more, or all of the movable components 161 and 162.

[0071] The movable component 161 may be arranged symmetrically relative to the electrode gap 282, for example, to achieve symmetrical actuation. Alternatively, the movable component may be arranged asymmetrically relative to the electrode gap 282, for example, to achieve asymmetrical actuation. Similarly, the movable component 162 may be arranged symmetrically or asymmetrically relative to the electrode gap 281.

[0072] Examplely, different potentials U3 and U4 can be applied to movable components 161 and 162, wherein, according to an embodiment, movable components 161 and 162 or their drive structures are electrically or current-connected to each other such that potentials U3 and U4 are the same or equal. Based on potentials U1, U2, U3, and U4, electrostatic forces can be generated, which can cause one or more movable components 161 and / or 162 to deflect along the direction of movement in the planar direction 18. Therefore, a driving force can be generated when the potentials of the movable structures interact with potentials U1 and / or U2.

[0073] The drive structure 22b may include an electrode structure, which is preferably formed in a structured manner, such as in the form of interdigitated electrodes. That is, other electrode components that can be connected to potential U2 may also be part of the drive structure 22b. However, according to other embodiments, individual electrode segments may also be electrically insulated from each other, such that, for example, the electrode components commonly provided with reference number 22b1 form electrode components that can be individually applied with potential.

[0074] like Figure 2aAs shown, additional drive structures 22c, 22d, and / or 22e can be arranged on the sides of layers 122 and 123 facing away from and away from movable components 161 and 162. In this case, the additional drive structures 22c, 22d, and 22e are optional. Specifically, drive structures 22d and 22e can be arranged in a stacked arrangement of the MEMS device for arranging additional movable components 16. Similarly, since movable components 161 and 162 are shown adjacent to drive structures 22b and 22c, the additional movable components can be arranged adjacent to drive structures 22d and / or 22e.

[0075] For example, in addition to using the driving structure 22b to provide a driving force component, the driving structure 22c on the MEMS layer 123 or wafer 44 can also be used to provide an additional driving force component between the movable components 161 and / or 162 and the driving structure 22c. That is, relative to the description of MEMS device 10, a first interaction between the movable component 161 and the driving structure of wafer 42 and a second interaction between the movable component 16 and the driving structure of wafer 44 can be provided at the movable component 16. For example, this control can be provided by a control unit (or control device) configured to apply a corresponding voltage or potential or control signal to the electrode or conductive structure. The driving unit can be configured to generate a first driving force component F1 based on the first interaction and a second driving force component F2 based on the second interaction. The MEMS device can be configured to generate the first force component and the second force component in the same direction or in phase, which can allow the movable component 161 to reciprocate parallel to, for example, the planar direction 18. The phase shift between force components F1 and F2 can cause tilting or rotation about the suspension center M, such as torsion of the movable component 161. Furthermore, in the case of anti-phase control, the configuration of force components F1 and F2 can enable the movable component 161 to reciprocate, for example, about a center point or central axis M. That is, the upper drive structure and the lower drive structure can provide force components that are displaced relative to each other based on individual control.

[0076] The driving unit may include other driving structures that can be arranged on the side of MEMS layers 122 and / or 123 opposite to the movable components 161 and / or 162, wherein the other movable components may be arranged adjacent to the driving structures to form a stacked arrangement with the movable components 161 and 162.

[0077] For example, the electrode structure can be connected to layers 122 and / or 123 via connecting layers 321 to 324, which may be particularly advantageous if layers 122 and / or 123 are formed of a semiconductor material. For example, layers 321 to 324 can be formed in an electrically insulating manner and contain, for example, silicon oxide and / or silicon nitride. Other materials can also be selected without limitation.

[0078] The movable components 161 and 162 can be optionally arranged symmetrically across gaps 281 to 284, which allows for symmetrical control of the movable components 161 and 162, for example, for linear movement. Nevertheless, off-symmetrical positions, such as in a stationary position, can also be provided to implement, for example, asymmetrical control.

[0079] Movable components 161 and 162 may move toward and away from each other during a control cycle, but alternatively may move in phase such that, for example, the distance between movable components 161 and 162 is equal or only does not change significantly. In other cases where movable components 161 and 162 alternately move toward and away from each other, for example, the volume of the sub-cavity 36 between movable components 161 and 162 alternately decreases and increases. For fluid exchange with the environment, openings 381 to 383 may be provided in any number and / or at any location in the first wafer 42 and / or the second wafer 44, such that fluid can flow into or out of the sub-cavity 36, which may provide, for example, a bottom wafer and / or a cover wafer, between which movable components 161 and / or 162 are arranged.

[0080] Figure 2b shows Figure 2a A schematic side cross-sectional view of a portion of an embodiment, wherein, for example, optional drive structures 22d and 22e are not shown.

[0081] In a comparable manner, Figures 2c and 2d show corresponding sections of the MEMS device 20. In Figure 2c, starting from the exemplary static state of Figure 2b, the movable components 161 and 162 move towards each other by a movement 48, causing the volume of the sub-cavity 361 between the movable components 161 and 162 to decrease. Correspondingly, on the side of the back ion cavity 361, the volume of the sub-cavities 362 and 363 adjacent to the movable components 161 and 162 increases, so that the correspondingly arranged openings 381 and 382 allow fluid 463 to flow into the sub-cavities 362 and 363, while the opening 38 allows fluid 46 to flow out of the sub-cavity 361.

[0082] Figure 2d illustrates a complementary situation, in which the movement 48 causes the movable components 161 and 162 to move away from each other, which can cause the volume of sub-cavity 361 to increase again, while the volume of sub-cavities 362 and 363 decreases, so that fluid 46 can flow in opposite directions, for example, into cavity 361 through opening 383, and out of sub-cavities 362 and 363 through openings 381 and 382 respectively.

[0083] For this purpose, Figure 2b shows exemplary force vectors F1a1, F1b1, F1b2, F1a2, F2a1, F2b1, F2b2, and F2a2, which indicate that exemplary conductive movable component 161 and / or exemplary conductive movable component 162 can generate a force capable of triggering movement 48 of Figure 2c or movement 48 of Figure 2d based on the potential of the electrode assembly of drive structures 22b and 22c.

[0084] As from Figure 2a As seen in Figure 2d, multiple movable parts 16 can be arranged along the planar direction 18 to alternately reduce and expand adjacent sub-cavities during control, thereby moving a large amount of fluid, which is particularly advantageous for pump or speaker applications.

[0085] In other words, conductive layers 22b and 22c can be divided into at least two discrete sub-regions 22b1 and 22b2 and 22c1 and 22c2 in a first direction. These sub-regions are electrically insulated from each other and separated by an insulating medium such as silicon oxide or a spacing 28 therein, and can form electrodes. The arrangement and interconnection of the electrodes are exemplarily configured as interdigitated. The spacing between these sub-regions is, for example, 1 μm, but can also be 10 nm or even up to 10 μm. As an example, a first group of sub-regions 22c1 and 22c2 is mechanically connected to the overlay wafer via an insulating connection layer 322. Another second group of sub-regions 22b1 and 22b2 is mechanically connected to the bottom wafer via an insulating connection layer 321. In one group of sub-regions such as 22b1 and / or 22c1, the first sub-region is connected to a first signal voltage, and the second sub-regions 22b2 and / or 22c2 are connected to a second signal voltage. For example, signal voltages can have the same value, but can also be shifted by, for example, 180° phase. The phase shift can also have other values. Electrically identical sub-regions of different groups can be arranged opposite each other on the overlay wafer and the bottom wafer.

[0086] Resistance components 161 to 16 nThe arrangement and geometry are described below, where n can be an integer multiple of one, i.e., an integer. The resistive component, i.e., the movable component, can be, for example, a beam-shaped component whose longitudinal extension direction is arranged in a second direction perpendicular to the first direction mentioned above, such as along the surface centroid fibers. This dimension is indicated in Figures 4a and 4b, for example, by parameter l. A preferred length is, for example, between 10 μm and 10 mm, a particularly preferred length is between 1 mm and 6 mm, and a particularly preferred length l is about 3 mm. The extension of the resistive component in the first direction, i.e., parallel to the direction of movement, is much smaller than its extension in the second direction. It should be noted here that a particularly preferred embodiment of the resistive component includes a variable width, such as along the first direction. The width of the resistive component is minimum in the region of its surface centroid fibers and can be located in the region of the neutral axis of the resistive component, in which case, reference point M. Towards its upper and lower edges, the width of the movable component can again increase at the edges. For example, the width of the surface centroid fiber region is between 3 μm and 4 μm. The width of the regions shown at the upper and lower edges is, for example, between 7 μm and 8 μm. The beam width can also be configured in other ways, that is, thinner in the middle and thicker at the edges, or thicker in the middle and thinner at the edges.

[0087] The extension, which may be referred to as, for example, height, and extending upward in a third direction, is, for example, between 400 μm and 5000 μm, preferably between 650 μm and 1500 μm, and particularly preferably about 1000 μm. This third direction is arranged perpendicular to the plane spanning between the first and second directions, for example, along a distance of 34. The shape of the resistive component may vary in width, as referenced. Figures 3a to 3d As shown.

[0088] The resistive components are arranged to overlap equally with two adjacent sub-regions (22c1 and 22c2, and 22b1 and 22b2) in the cover wafer region and the bottom wafer region. An insulating region 38 between the two sub-regions is also included in this overlap. The insulating region 28 between the two sub-regions may be formed of oxide (e.g., SiO2, Si3N4, or Al2O3) or air, and its width may be between 0.1 μm and 10 μm.

[0089] The resistive components 161 and 162 are spaced 261 and 262 from the electrodes of the conductive layer. For example, this distance is between 0.01 μm and 10 μm, preferably between 0.05 μm and 1 μm, and particularly preferably 0.1 μm. This spacing forms two portions of a capacitive actuator between the beam and the overlay wafer and the bottom wafer. Therefore, the actuator of the movable resistive structure / beam does not have direct mechanical contact with the resistive structure. This distinguishes this solution from other solutions where the actuator and resistive structure must be mechanically connected to obtain the acoustic effect from the resistive structure.

[0090] according to Figure 2a The balance brake (an actuator with linear deflection behavior) shown in Figure 2d illustrates different moments when the actuation resistance component is activated:

[0091] The following demonstrates the forces acting on resistance components:

[0092] The force pulling to the left (first direction of motion): F a1 =F 1a1 +F 2a1 =~(U DC +U ACa ) 2 / d

[0093] U ACa = Signal voltage applied to electrodes 2a and 5a / AC voltage.

[0094] The force pulling to the right (second direction of motion): F b1 =F 1b1 +F 2b1 =~(U DC +U ACb ) 2 / d;

[0095] U ACb = Signal voltage applied to electrodes 22c1 / 22c2 and 22b1 / 22b2 / AC voltage.

[0096] U DC This refers to the DC voltage applied between the cover wafer / bottom wafer and the device wafer.

[0097] d = Distance between the overlay wafer / bottom wafer and the device wafer 261, 262.

[0098] The force obtained on the resistive component is:

[0099] F1 = F a1 -F b1 =~(2*U DC *U ACa -2 UDC * UACb +U ACa 2 -U ACb 2 ) / d

[0100] If the signal voltage / AC voltage is U ACa =-U ACb =U AC Then the following equation applies.

[0101] F1 = ~4*U DC *UAC / d.

[0102] The resulting force and signal voltage U AC Linear correlation. The linearity between signal voltage and force is very important for the sound quality (distortion factor) of a loudspeaker.

[0103] a) For force balance, applicable: 22c1 and 22c2 or 22b1 and 22b2 have the same voltage U. ACa =U ACb All these forces are equal, F a1 =F b1 And F a2 =F b2 These resistance components are located equally below 22c1 / 22c2 or 22b1 / 22b2, respectively;

[0104] b) For the movement of the resistive component below 22c2 / 22b2, applicable: voltage U ACa ACb These forces have the following relationship with each other: F a1 <F b1 And F a2 <F b2 ;

[0105] c) For the movement of the resistive component below 22c1 / 22b1, applicable: voltage U ACa >U ACb These forces have the following relationship with each other: F a1 >F b1 And F a2 >F b2 ;

[0106] Figure 3a A schematic side cross-sectional view of a MEMS device 30 according to an embodiment is shown, which is modified relative to MEMS device 20 in several optional aspects. Although the principle effect of moving movable components 161 and 162 toward or away from each other can be the same in order to increase or decrease the volume of sub-cavities 361, 362 and 363 to allow fluid to move through openings 381, 382 and 383, the movable components 16'1 or 16'2 of MEMS device 30 include a modified configuration.

[0107] ​Unlike MEMS device 20, in which, as an example, movable component 16 is formed as a single conductive element, movable components 16'1 and 16'2 may be formed of semi-conductive or non-conductive materials, such that drive structures 22a and / or 22f are mechanically fixed to the movable components via layers 321 and / or 322 or their substrates and include electrode components 22a1, 22a2, 22f1, and 22f1. That is, unlike MEMS device 20, where electrode structures are arranged on substrate layers 122 and 123, electrode structures may alternatively or additionally be disposed on movable components 16'1 and 16'2. In this regard, drive structures 22a and 22f can be controlled or interconnected in the same or equivalent manner and can be made to have equal potentials, such as for electrode components 22a1 and 22f1 and 22a2 and 22f2, but may alternatively provide individual interconnections. That is, the electrode structure can be arranged on the side of the MEMS layer 121 or the movable component facing the MEMS layer 122 and / or the MEMS layer 123, and form at least part of the driving structure.

[0108] On the other hand, in the MEMS device 30, layers 122 and / or 123 may optionally be configured to be conductive, making a separate arrangement of electrode structures potentially unnecessary. Alternatively, layers 122 and 123 may have electrode structures as described in conjunction with the MEMS device 20.

[0109] Independent of, but also in conjunction with, this situation, layers 122 and 123 may have surface configurations 521 to 528, which can provide, for example, symmetrical control in the region of the relative electrode gap 28 and can be implemented in the form of protrusions or recesses opposite to the main side surface 122A or 123B. That is, the distance between the movable component and layer 122 or 123 in the region of configuration 52 can be locally increased by implementing the configuration as a recess in the material or locally decreased by implementing the configuration as a protrusion. In some embodiments, this surface configuration may be desired or required. For example, if electrodes are arranged on the movable component, it is advantageous to structure the bottom wafer and / or overlay wafer (or top wafer) in the same or similar manner as shown to allow movement. Electrostatic force adjustment can be obtained via configuration 52. In other words, surface configuration 52 may be a protrusion or a hole. This structuring may be arranged symmetrically on both sides of wafers 42 and / or 44. That is, the movable components 16'1 and / or 16'2 may have surface textures or surface configurations on the side facing the second MEMS layer 122, and / or the second MEMS layer 122 may have surface configurations or surface shapes on the side facing the movable components 16'1 to 16'2, so as to locally change the distance between the movable components 16'1 and 16'2 and the second layer 122, respectively.

[0110] While surface configurations 521, 522, 525, and 526 can be used to adjust the electrostatic forces between the drive structures for the illustrated control, surface configurations 523, 524, 527, and 528 can be used as dummy textures, for example, to minimize bending of wafers 42 and / or 44. Reference Figure 2a The structured conductive layers or electrodes 22c / 22e and 22b / 22d, it should be noted here, that the use of a structured electrode 22e having the same effect in a sub-region related to a sub-region of conductive layer 22c and / or a structured electrode 22d having the same effect in a sub-region related to a sub-region of conductive layer 22b, can achieve similar or the same effect in the sense of avoiding bending, regardless of Figure 2a Whether other movable components not shown are arranged adjacent to and / or 22d of the conductive layer.

[0111] However, optionally, in the presence of, for example, adjacent to Figure 2a In embodiments of the stacked arrangement of movable components of the drive structures 22d and / or 22e, corresponding adjustment possibilities can also be obtained for additional movable components (not shown) perpendicular to the movement direction 18 or along the layer stacking direction 14.

[0112] Figure 3b A schematic side cross-sectional view of a movable component 16” according to an embodiment is shown. This movable component 16” can be used, for example, as a movable component 16'1 or 16'2 implemented in a MEMS device 16. The substrate 54 of the movable component 16” can be formed, for example, from a semiconductor material such as silicon, and can have, for example, a generally rectangular geometry, wherein a thickening may also be provided at the ends of the substrate 54.

[0113] Unlike according to Figure 3a The planar arrangement of the electrode structure, with electrodes 22a1, 22a2, 22f1 and / or 22f2 also partially arranged on the side surface of the movable component 16” or the substrate 54, allows an electric field to be generated, for example, along these sides, which is advantageous in the case of dynamic movement of the movable component 16”.

[0114] The shape of the substrate 54 is independent of the implementation of the electrodes on the side surface. This implementation can also be effortlessly achieved at the movable components 161 and 162.

[0115] In other words, Figure 3a and Figure 3b Demonstrating the so-called balancing actuator. Figure 3a and Figure 3b Alternative embodiments of the basic cell exhibiting linear deflection behavior are shown. (Compared to...) Figure 2aThe difference from the embodiment in Figure 2d is the location of the conductive layer at the resistive component. By replacing the location therein, the resistive component is an active resistive component. Here, the resistive component is characterized in that each conductive layer is connected to the resistive component via an electrical insulating layer. The shape of the resistive component having conductive layers may vary in its width.

[0116] In addition, alternative deflectable and active resistance components were also demonstrated. Figure 3b Here, the conductive layer is partially arranged around the periphery of the resistive component. In other words, the conductive layer is arranged not only between the resistive component and the cover wafer and between the resistive component and the bottom wafer, but also on the sides of the resistive component surrounding the cavity.

[0117] Figure 3c exhibit Figure 3b A schematic side cross-sectional view of the substrate 54.

[0118] Figure 3d Display relative to Figure 3c A schematic side cross-sectional view of the modified base 54', compared to Figure 2a The substrate 54' has a single concave configuration and includes a multi-convex curved configuration.

[0119] The cross-section of the movable component can be polygonal, such as rectangular, single-curve, or multi-curve, wherein the curvature can be convex or concave, and multi-curvature also allows for mixed forms. Alternatively or additionally, in the cross-section along the stacking direction 14, perpendicular to the stacking direction, such as along the planar direction 18, the movable component has variable dimensions.

[0120] Figure 4a shows a schematic side cross-sectional view of the movable component 16'1 of the MEMS device 30 according to a first embodiment of the electrode structure. For example, electrode segments 22f2 and 22a2 may be arranged opposite each other on the substrate 54 regardless of its cross-section, and may provide planar contact, for example, along length l. In this regard, along the stacking direction 14, electrode segment 22a2 may have a height h5 and electrode segment 22f2 may have a height h2, which may result in a total height h of the movable component 16'1. ges .

[0121] Figure 4b shows that electrode assembly 22f2 and electrode assembly 22a2 are respectively structured into segments 561 to 56. 10 and 56 11 Up to 56 20 An illustrative side cross-sectional view of an alternative embodiment, wherein the number of 10 segments 56 is merely illustrative and may be any number of at least two, at least three, at least five, at least eight, at least ten or more.

[0122] As illustrated with respect to connector 58, segments 56 of electrodes 56f2 and 22a2 are electrically or current coupled to each other, such that when in groups 561 to 56 10 and 56 11 Up to 56 20 When a potential is applied inside, these segments have the same potential.

[0123] Here, the fragment may have a size l S This dimension, for example, includes values ​​within the range of 0.5 μm to 2 μm, but other values ​​may be implemented based on individual configurations. A distance l can be provided between two adjacent segments 56. abst The distance l abst The distance is constant or variable over a length l, wherein the two segments 56 are separated from each other but bridged by means of a conductive connector 58.

[0124] That is, the movable component can be configured along the component length l along an axial extension direction perpendicular to the stacking direction, such that electrodes 22a2 and / or 22f2 comprise a plurality of electrode segments 56. Adjacent electrode segments 56 can be electrically connected to each other by electrical conductors 58, wherein the electrical conductors have lower mechanical stiffness than the electrode segments along a direction perpendicular to the component length, such as along the planar direction 18. This allows the mechanical stiffness of the electrode material to impede movement or deformation of the movable component to a lesser extent.

[0125] In other words, the conductive layer can be segmented in the first direction, as shown in the side view of FIG4b. In this case, the segments are spaced apart from each other. Advantageously, the rigidity of the deflectable component can therefore be addressed in the design. In this case, the resulting gaps are preferably not filled. FIG4b therefore shows a view of an embodiment with a segmented electrode layer.

[0126] The amount of extension of the resistive component in the third direction is represented by h in Figure 4a, and the amount of extension of the conductive layer 22a or 22f is represented by h2 or h5. The ratio of h to h2 or h to h5 is 20%, preferably 5% or especially preferably 1%, that is, h2 and h5 are thinner than the substrate 54.

[0127] The extension of the resistive component in the first direction is shown in particular in Figure 4b. Here, an alternative arrangement of conductive layers 22a and 22f is shown, which, as mentioned above, reduces the rigidity of the deflectable component. The length of the resistive component in the first direction is represented by l. The length of the segment is represented by l. S Represented. The distance between segments is represented by l. abst express.

[0128] Figure 5aA schematic top view of a portion of the MEMS device 501 according to an embodiment is shown, particularly according to an embodiment of movable components 16'1 to 16'5, which are illustratively formed corresponding to movable components 16'1 and 16'2 of the MEMS device 30. For the movable components 16'1 and 16'5, sub-cavities 361 to 366 are arranged between adjacent movable components or between the movable components and the surrounding substrate 62. The movable components 16'1 to 16'5 can be considered as beams fixedly clamped on both sides, with the interdigitated interconnection of electrode assemblies 22a1 and 22a2 shown as an example. It can be seen that the respective electrode assemblies of adjacent movable components 16'1 to 16'5 can have the same potential due to continuous interconnection, but breaking this configuration may also result in individual interconnection.

[0129] A direct current (DC) voltage can be applied to electrode assemblies 22a1 and 22a2, such that the DC voltage is applied alternately to electrodes 22a1 and 22a2, for example. Alternatively, an AC voltage, as indicated by AC- and AC+, can be applied. This configuration can also occur simultaneously, for example, to generate an attractive force between adjacent movable components to move them toward each other.

[0130] In other words, Figure 5a This diagram illustrates the contact of the electrodes when they are connected to the beam (movable component). Similarly, this configuration can be implemented for electrodes facing the overlay wafer and / or the bottom wafer.

[0131] As from Figure 5a As can be seen, the movable components 16'1 to 16'5 can be directly configured to interact with a fluid, for example by moving the fluid or a body moved by the fluid. Alternatively, additional components, such as plate assemblies or the like, can be arranged on the movable components, which move through the movable components and thus interact with the fluid.

[0132] Figure 5b With Figure 5a The corresponding view shows a schematic top view of the MEMS device 502 according to an embodiment. However, unlike the MEMS device 501, the movable component is formed as a movable component 16", such as, for example... Figure 3b As shown in the figure. That is, in addition to the top or bottom surface, electrodes 22a1 and 22a2 also extend along the sidewalls of the movable component. However, it should be noted here that terms such as up, down, left, right, front, back and the like are not restrictive but merely illustrative, as these terms are obviously interchangeable due to changes in the orientation of the subject in space.

[0133] However, it is evident that when the movable components 16”1 to 16”5 move or deform along the moving direction 18, advantages can be obtained by structuring the electrodes, as shown in Figure 4b or Figure 5b The electrical connection 58 between two adjacent segments 561 and 562 can be achieved, for example, by locally thinning or removing the corresponding electrode, but this can result in low mechanical resistance of the electrode assembly when the movable component 16”1 is bent.

[0134] In this regard, sub-cavities 361 to 366 can be part of the entire cavity, and due to the movement of movable components 16”1 to 16”6, the size of sub-cavities 361 to 365 can alternately expand and shrink.

[0135] The movable components of MEMS devices 501 and 502 can be fluidly coupled to each other, such that when only one of the movable components is actuated, a neighboring movable component can also move in an inactive state. That is, fluid movement can be coupled to a neighboring movable component, regardless of whether the neighboring movable component is actuated or not. Optionally, the neighboring movable components can also be coupled to each other, for example, in the central region, such as at 1 / 2, by means of a coupling component not shown. This coupling component enables uniform movement of the coupled movable components.

[0136] As further illustrated in MEMS devices 501 and 502, different potentials can be applied to electrodes 22a1 and 22a2. In this regard, an interdigitated structure can be formed such that electrodes of adjacent movable components facing each other are connected to a combination of potentials AC- and AC+, that is, the two facing electrodes have different potentials, or in other words, different electrodes 22a1 and 22a2 with different potentials face each other. The same applies to DC connections, which, for example, alternate between electrodes 22a1 and 22a2, such that the connected electrode faces the unconnected electrode.

[0137] In other words, Figure 5a and Figure 5b Top views of the embodiments shown in Figures 4a and 4b are presented respectively, wherein Figure 5b It also shows the contact of the electrodes when connected to the beam. Figure 5a and Figure 5b This is a top view of the layers in Figures 4a / 4b of a MEMS-based transducer with linear deflection behavior in a simplified embodiment having a finite number of active deflectable components. The illustration shows the possible electrical connections of the active deflectable resistive components shown in Figures 4a / 4b. Here, the two sub-regions are interlocked in a comb-like manner (in other words, interdigitated) and arranged along the entire length of the respective passive resistive component. Similarly, this embodiment can also be implemented for electrodes facing the overlay wafer and / or the bottom wafer.

[0138] Figure 6 A schematic side cross-sectional view of a portion of a MEMS device 60 according to an embodiment is shown. Here, in addition to the cavity 66, which is subdivided into sub-cavities by means of four movable components 16'1 to 16'4, an outer region is also shown, in which the interconnection of electrodes is shown in more detail. Recesses 641 to 647 expose electrodes and / or other areas, making them ready for contact. As shown with reference to recesses 641 to 645, this exposure allows access to all electrodes along the side of the MEMS device 60.

[0139] Figure 7a A schematic side cross-sectional view of a MEMS device 70 according to an embodiment is shown. For example, the MEMS device 70 includes a configuration as described in conjunction with MEMS device 20. Specifically, any two adjacent movable components 161 and 162, 163 and 164, and 165 and 166 may form basic cells 681, 682, and 683 of the MEMS device 70, respectively. Although openings 381, 382, ​​and 383 of wafer 44 may be exclusively associated with, for example, basic cells 681, 682, and 683, openings 384 and 385 of wafer 42 may be shared by adjacent basic cells 681 and 682 and 682 and 683, respectively.

[0140] Recesses 641, 642, 643, and 644 may be disposed in substrate layers 122 and 123 for contacting electrodes 22c1, 22c2, 22b1, and 22b2, respectively. Alternatively or additionally, recesses 645 and / or 646 may be provided for partially exposing layer 121 to connect the layer to a potential, such as a reference potential (GND).

[0141] In other words, Figure 7a A cross-sectional view of an embodiment of a MEMS-based transducer with linear deflection behavior is shown, the MEMS-based transducer having three adjacent basic cells. A structure with passively deflectable resistive components is shown. Thus, conductive layers are each connected to the bottom wafer and the cover wafer via electrical insulating layers. Basic cells are interconnected via cavities of adjacent passively deflectable resistive components. Furthermore, the locations of possible lower and upper exit openings in the bottom wafer and cover wafer are shown. A region 64 is provided for electrical contact sublayers. Similarly, regions are provided for electrical contact with other electrodes in sublayers. Contact regions are shown as openings, such as holes or square recesses or rectangular trenches etched down into the corresponding conductive layers. This embodiment is not limited to the locations of the conductive layers shown. To establish a potential difference between layers 22b and 22c and the passively deflectable components, contact with GND can be made in layer 121. Similarly, according to… Figure 3a The structure with an active deflectable component, as shown in Figure 4b, is possible.

[0142] Figure 7a Contacts with the chip will be made, for example, via wire bonding. Because the contact holes are located on both sides of the chip, the wire bonding process must also be performed from both sides.

[0143] Figure 7b Conductive components 721 to 726 are arranged in Figure 7a A schematic side cross-sectional view of the MEMS device 70 in an embodiment where the groove 641 allows contact with the corresponding area.

[0144] Conductive areas or components 721 to 726 may be spaced apart from the surrounding material by gaps 741 to 744, wherein the gaps may optionally be filled with an electrically insulating material. For example, a conductive structure 76 made of the material of conductive component 72 or another conductive material may be arranged to prevent short circuits by electrically insulating the connecting layer 32; such conductive structures 76 may be surrounded in the region surrounding the electrode by the material of the connecting layer 32 or its electrically insulating properties. Here, component 725 may provide contact between sub-regions of layers 121 and 123, as shown in component 726. In this respect, component 725 may also be electrically insulated from other components, such as sub-regions of conductive layer 22c. In this case, contact may be provided on both sides.

[0145] In other words, Figure 7b This invention illustrates a transducer with linear deflection behavior and an alternative structure for a MEMS-based transducer, differing in its contact and conductive layer 101. In this case, contact with the layers is not achieved via grooves. Instead, the layers are connected to the cover wafer and the bottom wafer via vias through conductive components. Layer 121 is connected to the bottom wafer or the cover wafer via conductive plugs. Potential separation in the cover wafer or the bottom wafer is achieved via separators (or grooves). The advantage of this embodiment is that contact between the layers does not occur in grooves, but rather on the surface of the bottom wafer or the cover wafer.

[0146] Figure 7c A schematic side cross-sectional view of a similar MEMS device 70' is shown, wherein contact is made only from one side of wafer 44 (e.g., overlay wafer) via grooves 741 to 745. Accepting relatively deep trenches allows the MEMS device 70 to be easily placed on the substrate, since electrical interconnections from one side may be sufficient.

[0147] In other words, when a conductive layer is placed on a resistive component, electrode contact can occur in several ways. Electrode contact can occur from both sides or only from one side. Figure 7c Demonstrating a transducer with linear deflection behavior: it is similar to Figure 3aIn addition to contacting from one side of the chip, all electrodes necessary for actuation can be accessed from one side of the chip (via a recess). In this case, wire bonding of the finished chip is easier to implement because the chip can be wire bonded from only one side.

[0148] Similar to Figure 7a The contact options shown in the image can also be used. Figure 3a The driving variant in the middle.

[0149] Figure 8a A schematic side cross-sectional view of a MEMS device 80 according to an embodiment is shown, wherein subcavities 361 to 367 extend partially into at least one of layers 122 and 123 by providing recesses 78 in layers 122 and 123, for example, in the regions adjacent to openings 381 and 382, ​​382 and 383 and / or in the regions of openings 384, 385, 386 and / or 387.

[0150] Examplely, layer 121 can be connected to an AC potential U AC or -U AC or +U AC This allows this potential to also be applied to movable components 161 to 166. In contrast, layers 122 and 123 can be connected to a reference potential GND.

[0151] Figure 8b The display features a slightly different configuration. Figure 8a A schematic side view of a MEMS device 80, wherein although movable components may be individually or in groups connected to a voltage DC or AC+, as combined Figure 8a As described, the substrate surrounding layer 121 is connected to a reference potential, which allows for easy and safe disposal of the MEMS device. Optionally, instead of configuring the substrate to be connected to the reference potential, electrical insulation can be provided on the MEMS device 80. Figure 8b The MEMS device 80 is shown in the following state: the movable components 161 to 166 have moved in pairs toward each other within the basic cells 681, 682 and 683, such that the corresponding main sides 161A and 162A and 163A and 164A of the defining sub-cavities 362 and 364 move toward each other respectively.

[0152] Figure 8c Showing a complementary state Figure 8b A schematic side view of the MEMS device 80, in which the movable components 161 and 162, 163 and 164 and 165 and 166 of the individual basic cells 681, 682, 683 move away from each other to generate reverse fluid flow.

[0153] In other words, Figures 8a to 8c Demonstrating a transducer with nonlinear deflection behavior: Figures 8a to 8c The structure of a MEMS-based acoustic transducer in three deflection states is shown. Similarly, a simplified structure with two electrodes is shown. Here, the layer covering wafer 123 and the bottom wafer 124 forms the first electrode, and the layer housing the wafer or passively deflectable resistive component forms the second electrode. The resistive component is shown in a simplified form in this embodiment and may have other cross-sections, such as those described herein. The resistive component is disposed in a cavity machined in layer 121 by an etching process and extends through other layers, namely the cover wafer and the bottom wafer. At least one end, preferably two opposite ends, is connected to the substrate of layer 121. Preferably, these layers have a cover wafer structure and a bottom wafer structure that result in a large volume of cavity. These layers are connected to layer 121 via insulating layers 321 / 322.

[0154] The resistive component has main sides. The main sides are characterized in that they are arranged opposite to each other in the presence of adjacent resistive components, and define sub-cavities 362, 364, and 366 connected to the upper outlet openings 381 to 383. Therefore, the opposite sides of the resistive component are characterized in that they surround cavities 361, 363, 365, and 367 simultaneously connected to the lower outlet openings 384 to 387. Furthermore, the opposite sides of the resistive component are characterized in that they define sub-cavities 361, 363, 365, and 367 that connect basic cells to each other.

[0155] Figure 8a The resistant component is displayed in its unbiased state.

[0156] Figure 8b The resistive component is shown in a deflected state during a first time interval under an additional applied voltage (a combination of DC and AC), the applied voltage being between 0V and 100V, preferably between 1V and 50V, particularly preferably between 1V and 25V, approximately 24V. Here, the resistive component deflects along the direction of movement 18. Adjacent resistive components of the basic cell move toward each other, such that the distance between the corresponding main sides decreases and the volume of sub-cavities 362, 364, 366 decreases accordingly. As the volume of the sub-cavities decreases, fluid is discharged from the sub-cavities through outlet openings 381 to 383. During the same time interval, opposite sides of the resistive components move in one direction, such that the distance between the opposite sides increases. Similarly, the volume of the cavities 361, 363, 365, 367 enclosed thereby also increases. The resulting volumetric flow delivers fluid to the sub-cavities through openings 384 to 387.

[0157] Figure 8cThe resistive component is shown in a deflection state during a second time interval immediately following the first time interval. For a considerable period, the first and second time intervals alternate in this sequence, causing the emission of pressure pulses, such as sound waves.

[0158] During the second time interval, a different voltage (DC+AC) is supplied to the resistive component, which is phase-shifted by, for example, 180° compared to the voltage during the first time interval, wherein other phase angles may also be adjusted. The phase shift may also be other values ​​greater than zero. Therefore, the resistive component moves along the direction of movement 18 in the opposite direction to that during the first time interval. In other words, the distance between opposite sides of adjacent resistive components decreases, thereby increasing the volume of sub-cavities 362, 364, and 366, and thus, a volumetric flow of fluid is delivered into the sub-cavities through openings 381 to 383. Similarly, the distance between opposite sides of adjacent resistive components decreases, causing a volumetric flow of fluid to be delivered out of sub-cavities 361, 363, 365, and 367 through openings 384 to 387.

[0159] Figure 9 A schematic perspective view of a portion of a MEMS device 90 according to an embodiment is shown, for example, in the form of wafer 42 and layer 121. For example, ten movable components 161 to 166 are shown, which can be connected by sub-cavities 361 to 362. 11 Surrounding. Reference number 15 shows a step, chamfer, or rounding that causes the interior region of the movable component 16 to be recessed or lowered in height relative to the surrounding region of the remainder of layer 121, so that no mechanical contact with the movable component 16 occurs during subsequent bonding processes, such as for arranging wafer 44.

[0160] In other words, Figure 9 A perspective view of a MEMS-based acoustic transducer is shown. The layer containing the passive resistive components and the layer connected to layers 22b1 / 22b2 (bottom wafer) are shown. The layer covering the wafer is not shown. Similarly, an implementation of layers 22b1 and 22b2 interlocked in a finger-like manner and thus arranged adjacent to each other in the region where the passive components can be deflected is shown. Layers 22b1 / 22b2 are electrically isolated by region 28, which constitutes an electrical insulator. In this regard, layers 122 and 121 have different thicknesses. For example, layer 122 has a thickness of 400 μm. For example, the thickness of layer 121 can have a value between 400 μm and 5 mm. The contacts in layer 121 are connected using 72... i As shown, these contacts, along with other contacts in the layer not shown, connect the control to conductive layers 22b1 / 22b2. The control signal is then distributed to the corresponding areas of layers 22b1 and 22b2 by means of appropriate contacts 72.

[0161] Another aspect of this embodiment is the arrangement of the openings 38. In this embodiment, these openings connect the cavities 36 (in other words, grooves or recesses) to the surrounding fluid. In this embodiment, these openings are shown to be rectangular. In this embodiment, each cavity 36 connects to two openings, each of which is discretely spaced apart. However, similarly, the openings may also occupy the entire length of the passive resistance component or a different length. Similarly, the embodiment is not limited to a rectangular shape. Other shapes deviating from a rectangular shape are part of the embodiment and are only mentioned herein.

[0162] Reference number 15 refers to a peripheral step, chamfer, or rounding disposed between layer 121 and the substrate of the resistive component. With a height difference of approximately 100 nm, the substrate of the resistive component is slightly recessed relative to substrate 121 to prevent strain on the resistive component during the necessary bonding process of the capping layer. Similarly, a step may also be provided in the bonding region of layer 122.

[0163] Figure 10 A schematic perspective view of a MEMS device 100 according to an embodiment is shown. Compared to other embodiments described herein, movable components 161 to 199 are components that are fixedly clamped on only one side, wherein, as an example, adjacent movable components are fixedly clamped on opposite sides and can be arranged in the sense of interdigitated components. That is, the embodiments described herein are not limited to movable components clamped on both sides.

[0164] In other words, Figure 10 Another embodiment of a MEMS-based acoustic transducer 100 is shown, which includes deflectable resistance components 161 to 169 connected on one side to the surrounding substrate of layer 121, wherein several resistance components can also be arbitrarily configured here.

[0165] Figure 11 A schematic perspective view of a MEMS device 110 or a portion thereof (i.e., layer 122) according to an embodiment is shown, which may include an opening 38 and interdigitated electrodes 22b1 and 22b2, the interdigitated electrodes 22b1 and 22b2 possibly including contacts 721 to 72 that are permeable to the electrodes 22b1 and 22b2. 12 For example, such as combining Figure 7b exemplified.

[0166] In addition, spacers 84a and / or 84b may be provided to limit the distance between the movable component and itself across layer 122, specifically to a minimum distance. These spacers may be formed of, for example, an electrically insulating material and prevent the overlay wafer and / or bottom wafer from bonding to the fins over a large area during wafer-level bonding, because the spacers are relatively small, in the range of a few micrometers. The spacers may be used as fuse delivery wires. For example, spacers 84a and / or 84b may be removed, for example, with a specific hydrofluoric acid combination, such as HF vapor phase etching (GPE), before the chip is put into use. The spacers are optional and may also be provided only on a portion of the movable component.

[0167] In other words, Figure 11 Showing a perspective view and detail of layer 122 based on MEMS acoustic transducers. Figure 9 The implementation methods described herein.

[0168] Figure 12a A schematic top view of a portion of the MEMS device 1201 according to an embodiment is shown. Inventively, the electrode 22b2 is rectangular in shape and is arranged substantially centrally across the gap between two adjacent movable components 161 and 162, as shown, for example... Figure 2a As shown in the illustration. For example, movable components 161 and 162 can be formed in a comb shape.

[0169] Figure 12b A schematic top view showing a portion of the MEMS device 1202, wherein movable components 161 and 162 may be formed, for example, hollow bodies, which allows for material savings. Independently, electrode 22b2 may be configured, for example, as concave.

[0170] Figure 12c A schematic top view showing a portion of the MEMS device 1203, wherein movable components 161 and 162 are formed as solid bodies, and independently, electrode 22b2 is formed as a convex shape. Figure 12a , Figure 12b and Figure 12c The different details can be easily combined. That is, the electrodes of the drive structure arranged on the substrate can have constant or variable lateral dimensions along an axial path perpendicular to the layer stack direction, i.e., parallel to the plane direction 18. The above applies to electrodes on or in movable components.

[0171] In other words, Figures 12a to 12c A top view of the region replacing the basic cell is shown, illustrating various embodiments of the deflectable resistance component. In this regard, Figure 12a Demonstrates a comb-shaped implementation method. Figure 12bThe illustration shows a deflectable resistance component and a concave embodiment of layer 22b2. Furthermore, it demonstrates that the resistance component can be a thin-walled body without material in the region of the centroid fiber. In contrast, Figure 12c The diagram illustrates a convex configuration of the basic cell-based component. Advantageously, this implementation is used when, for example, a force is required during deflection and the rigidity of the resistive component must be optimized (e.g., minimized). Alternatively, the increasing demand for a stress-free transition between the resistive component and the surrounding substrate makes it useful to widen the resistive component in the transition region. Similarly, the deflection shape of the resistive component may be affected. Those skilled in the art will understand that hollow resistive components possess a lighter weight characteristic than filled resistive components. Therefore, the transducer's performance can be directly affected by the geometry of the resistive component. Undoubtedly, various embodiments can also be combined in MEMS transducers.

[0172] Figure 13 A schematic side cross-sectional view of a portion of a MEMS device 130 according to an embodiment is shown. Here, for example, layers 122 and / or 123 are formed to be conductive and divided into different segments or regions by means of electrically insulating components or areas or segments 92, allowing different potentials 86a / 86b and 88a / 88b to be applied to these segments or regions respectively, while a reference potential can be applied to layer 121 having illustrative H-shaped movable components 161 and 162. For example, potential 86a may be AC- and potential 86b may be AC+, and / or DC potentials may be applied alternately to different segments. The above applies to potentials 88a / 88b.

[0173] In other words, Figure 13 This demonstrates a resistant component exhibiting linear deflection behavior. Here, Figure 13 Display according to Figures 8a to 8c Another embodiment differs in the H-shaped implementation of the resistive component and the dual-potential guidance in the overlay wafer and the bottom wafer, respectively.

[0174] A resistive component exhibiting linear deflection behavior: This refers to the generation of electrical forces 86 and 88 when a voltage of 121 is applied. When voltages 86a / 86b and 88a / 88b are equal, the forces are balanced and the resistive component does not move. However, if the voltages between 86a / 86b or 88a / 88b are different, an imbalance occurs and the resistive component moves linearly in one direction. If the voltages between 86a / 86b or 88a / 88b are opposite, the resistive component moves linearly in the opposite direction. Advantageously, this results in a very large volume of surrounding cavity, allowing the resulting transducer to have a large sound pressure level. However, this also requires a large force and a large deflection of the resistive component. For this reason, this design allows for a linear relationship between the applied deflection force and the applied voltage.

[0175] Figure 14 A schematic side cross-sectional view of a MEMS device 140 according to an embodiment is shown, which may be consistent with MEMS device 130. However, unlike MEMS device 130, MEMS device 140 may include block-shaped or solid movable components 161 and 162.

[0176] In other words, Figure 14 Demonstrates a resistant component exhibiting linear deflection behavior. Figure 14 This is to materialize solid resistance components. Figure 13 .

[0177] Figure 15a A schematic side cross-sectional view of a MEMS 150 according to an embodiment is shown, wherein an electrical insulating layer 323, such as insulating layers 321 and 322, is formed around layers 122 and 123, as in the example electrode layers 221 and 222. This enables simple wafer bonding.

[0178] In other words, Figure 15a An embodiment of a MEMS-based acoustic transducer is shown in cross-sectional view. This embodiment illustrates a MEMS acoustic transducer during a method step in its fabrication. Spacers 84 are visible here, vertically connected to both sides of the resistive components. These spacers represent force dissipation points that enable uniform bonding of layer 121. In another step of the fabrication process, these spacers are then removed. Similarly, it is conceivable that these spacers also serve as transport protection members, allowing for lossless transport during the fabrication process. It is also conceivable that these spacers are broken only upon the first application of a signal, thus providing transport protection throughout the B2B process. Because many such spacers exist on the chip, they can be designed to have different sizes, such that when spacers are removed, only some spacers are selectively removed while others remain: smaller spacers are removed and larger spacers are retained. This allows for the selective release or movement of only certain resistive components. In this way, the same chip can be used or distributed for different applications (with more or less free resistive components).

[0179] Figure 15b A schematic side view of an intermediate product 150' for a MEMS device according to embodiments described herein is shown. It illustrates that material 94 is retained in the central region when etching is performed from the first side 961 and the second side 962 to form recesses 981 to 988. Once etching has been performed such that the opposing recesses are in contact and the material 94 is released, the movable component can be released. For example, the intermediate product 150' may also be a bonded wafer sample and / or a high-thickness wafer, wherein a double aspect ratio can be achieved due to etching on both sides.

[0180] Figure 15b This diagram shows a cross-sectional view of an embodiment of the transducer. This illustration is not intended to claim a method for manufacturing MEMS. Rather, it demonstrates the advantages of the structure claimed by the device. An important aspect of this invention is that the resistive component must be designed symmetrically to ensure uniform deformation during movement. Asymmetrical designs will result in the non-uniform deformation behavior just described. Therefore, there will no longer be a linear relationship between the applied voltage and the deflection of the resistive component, leading to a high distortion factor. The method used in the etching process produces the asymmetrical structure. Grooves, trenches, or cavities are formed by machining the material, without parallel edges, and are always funnel-shaped. The width of the bottom of the groove is always less than the width of its top.

[0181] Therefore, the etching direction of the wafer and subsequent connections significantly determine the formation of resistance components.

[0182] Similarly, Figure 15b The illustration shows that a stack of resistive components can increase the aspect ratio of the transducer assembly without being constrained by the applied Bosch method.

[0183] The illustration shows the device wafer etched from both sides (front and back) to increase the aspect ratio of the resistive components. Wherein:

[0184] Layers 981 to 984 have an etching direction from the front side;

[0185] Layers 985 to 988 have an etching direction from the rear side.

[0186] • Layer 94 is shown only schematically to demonstrate that the etching will eventually connect; 94 is no longer present in the final product.

[0187] Advantages of etching from both sides:

[0188] - The fins are symmetrical with respect to the plane spanned by the first and second directions. Therefore, the regions 96F1 and 96F2 shown are equal, and the electrical forces to be applied to deflect the resistive component in the direction of motion are equal. Thus, uniform deflection of the same amount is ensured.

[0189] If two layers are etched from only one side, surfaces 96F1 and 96F2 are not uniformly configured, or they may even be misaligned with each other in their surface areas. This will result in uneven deflection of the resistance components.

[0190] - This doubles the aspect ratio of the groove (in other words, the channel) to 60. By stacking the resistance components, the resulting transducer assembly is no longer limited to the Bosch method.

[0191] Figure 15cA schematic side view of a portion of the MEMS device 150” according to an embodiment is shown. In this regard, as an example, movable components 161 and 162 can be obtained by stacking a structure similar to intermediate product 150’, which is done by stacking multiple such intermediate products, such as by wafer bonding. It should be noted that... Figure 15c Only showable Figure 15b Two of the three movable components obtained are shown. By increasing the aspect ratio, which is implemented accordingly by combining them along the planar direction 14, an improvement in efficiency can be obtained, for example, by means of a speaker configuration of a MEMS device, for example, because the sound pressure level (SPL) is correspondingly increased. Furthermore, stacking along the layer stacking direction 14 enables high rigidity along this direction, which may result in lower sensitivity to the so-called pull-in effect, and thus may result in lower holding force or lower vertical deflection parallel to the layer stacking direction 14, which is advantageous. Therefore, a structure is shown in which the movable component comprises multiple layers connected by means of a bonding process.

[0192] To increase SPL, such as Figure 15c As shown, several layers can be connected together. In this way, the aspect ratio of trenches or resistive components can theoretically be greatly increased. Here, the "continuity" of the device layers is advantageous compared to the necessary support layers reported in the prior art (e.g., the disposal wafer in a BSOI wafer).

[0193] based on Figure 16a , Figure 16b and Figure 16c This illustrates the configuration of electrodes on the movable component, where N-doping in electrodes 22a1 and 22f1 or p-doping in electrodes 22a2 and 22f2 can be used to obtain the electrodes. A reference position can be obtained by connecting layers 122 and / or 123, where the distance may be locally reduced, to a reference potential such as 0V (GND). When a negative voltage is applied to layers 122 and 123, force can be applied to the movable component 16 due to the accumulation of movable positive holes in regions 22f2 and 22a2, resulting in electrodes 22a2 and 22f2 being subjected to an external negative voltage (AC-) over a small distance range. Figure 16c The complementary configuration is shown, in which a large number of mobile negative electrons accumulated in regions 221 and 22a1 move toward surface configuration 52 due to the positive voltage on layers 122 and 123.

[0194] The accumulation of mobile negative electrons can correspond to the loss of immobile cations, and vice versa. Since loss immediately follows accumulation, a space charge region can be generated.

[0195] Electrical insulating layers 1021 and 1022, such as those containing silicon nitride or silicon oxide, can be arranged to neutralize the surface state and maintain the most neutral state of the movable component 16.

[0196] Figures 16a to 16c Each figure illustrates an alternative drive based on a cover drive, exhibiting linear deflection behavior. Advantageously, this configuration improves upon common linear structures providing three electrodes. All three figures substantially disclose the connection of layers to the deflectable component, the layers comprising N-doped and P-doped regions arranged adjacent to each other and each connected to the deflectable component. These layers are cover wafers and bottom wafers with bumps 52 formed in the deflectable component region. These bumps are integrally connected to the cover wafer and the base wafer and have minimal distance from the deflectable component, thereby preventing acoustic short circuits between sub-cavities adjacent to the deflectable component. Figure 16a The device is shown in its undeflected state without any applied voltage.

[0197] Figure 16b The alternative drive is shown in the first deflection state. The deflection of the deflectable component is based on the field effect. In this figure, the deflection in the first direction is shown. The deflection is based on a negative voltage AC- applied to the overlay wafer and the substrate wafer. Due to the field effect, charge carrier accumulation occurs in the P-region (moving holes / + directly at the interface with the oxide, 10 to 20 nm deep). This accumulation is accompanied by a loss region in the N-region (immovable ions / -, 1 to 2 μm deep). When the fin overlaps with the overlay in the P-region, a maximum capacitance change equivalent to the deflection force occurs.

[0198] Figure 16c The alternative drive is shown in the second deflection state. The deflection of the deflectable component is based on the field effect. In this figure, the deflection in the second direction is shown. The deflection is based on a positive voltage AC+ applied to the capping wafer and the substrate wafer. Due to the field effect, charge carriers accumulate in the N-region of the layer (moving holes / + directly at the interface with the oxide, 10 to 20 nm deep). This accumulation is accompanied by a loss region (immobile ions / -, 1 to 2 μm deep) in the P-region of the layer. When the fin overlaps with the capping layer in the P-region, a maximum capacitance change equivalent to the deflection force occurs.

[0199] refer to Figure 17a , Figure 17b and Figure 17c This indicates a complementary configuration, wherein n-doped regions 22c1 and 22b1, respectively disposed on or integrated into layers 122 and 123, are arranged adjacent to p-doped regions 22c2 and 22b2. These regions may be covered by electrical insulating layers 1021 and / or 1022.

[0200] In this regard, the movable component 16 may also be formed to be conductive, for example, through corresponding doping. Based on the application of a negative voltage AC- or a positive voltage AC+, the movable component 16 can be triggered to move toward the n-doped regions 22c1 and 22b1 or toward the p-doped regions 22b2 and 22c1.

[0201] In other words, Figures 17a to 17c exhibit Figures 16a to 16c The alternative driver is based on the field effect, in which the doped layer is integrated into the cover wafer and the bottom wafer.

[0202] Figure 18a A schematic top view of a MEMS device 180 according to an embodiment is shown. Compared to other embodiments described herein, movable components are mechanically connected to the MEMS layer 123 via resilient regions, which... Figure 18a Not illustrated. In this regard, the elastic region may comprise layers arranged for this purpose, additional layers, or materials specifically provided for this purpose. The movable component is configured to perform rotational movement or deformation of the elastic region based on a driving force.

[0203] For example, the flexible area can be set in area 104.

[0204] Figure 18b exhibit Figure 18a A schematic side cross-sectional view in the A-A' plane. Due to the mechanical and elastic connections in region 104, movable component 162, such as when connected to other movable components of layer 123, can perform movement adjacent to layer 122. This movement is similar to rocking or seesaw movement, allowing for high-amplitude movement adjacent to layer 122 and low-amplitude movement within the region of layer 123, but with high material expansion.

[0205] The advantage of this configuration is that it requires only two instead of three active slices / wafers, and there is no need to provide additional layers for this purpose, such as in the area of ​​capping layer 123.

[0206] As explained in conjunction with other embodiments, the driving unit can be implemented in various ways, such as by disposing electrodes on layer 122 and / or movable component 162 and / or by arranging, for example, doped regions. The electrodes on the side of movable component 162 facing layer 122 (front side) can be referred to as face-driven. Thus, this front-side driving forms one embodiment of the invention. In other words, by correspondingly arranging the device wafer, the fin (movable component 162) can be driven from the front side of the fin. For example, at least on the front side, the first driving structure can be arranged at least on the front side of the movable component. For example, the electrodes can be arranged on or in layer 121. For example, the positioning can be located on the front side between movable component 162 and the side of layer 121 associated with the front side of the movable component. The height of the electrodes can be equal to or less than the height of the movable component.

[0207] In other words, Figure 18a and Figure 18b Top and side views show an alternative structure for the acoustic transducer. This differs significantly in the connection between the deflectable component and the cover wafer in region 104. This connection is preferably made using a material-locking method. The alternative direction of movement, perpendicular to the lateral extension of the resistive component, is indicated by 18. Here, maximum deflection occurs in the region of the bottom wafer. Minimum deflection occurs in region 104, i.e., the connection region between the resistive component and the cover wafer. The rigidity of the connection region 104 may differ from, and is preferably lower than, the rigidity of the cover wafer and the resistive component. In this case, the connection region 104 is a spring assembly. Sub-cavities resulting from the separation of the resistive components from each other are connected to the surrounding fluid (not shown) via openings in the bottom wafer and the cover wafer.

[0208] refer to Figure 19 The schematic flowchart illustrates a method according to an embodiment described herein. Step 1910 of method 1900 may include controlling two drive structures arranged along a layer stack direction, along which a plurality of MEMS layers of a MEMS device are arranged. Step 1920 includes generating a drive force perpendicular to the layer stack direction at a movable component of the MEMS device by means of the control to deflect the MEMS device.

[0209] This method can be performed in a manner in which two adjacent electrode assemblies of the drive device are electrically insulated from each other by an electrode gap in the sense of so-called "balanced" or linear control, and the symmetrical and / or linear deflection of the movable component is controlled by symmetrically controlling the electrode assemblies with respect to a reference potential (e.g., GND) over time with respect to the applied potential. Alternatively, the method can be performed asymmetrically, unbalancedly, or nonlinearly by controlling the movable component to deflect asymmetrically over time with respect to the actuation direction in the opposite direction. This can be achieved by using different potential levels and / or different time intervals.

[0210] The embodiments described herein relate to microelectromechanical systems (MEMS) configured to have a large effective area for interacting with fluids. In this regard, in some embodiments, increasing the effective area of ​​the deflectable displacement component is a primary concern. The displacement component (movable component 16) can contact and interact with the surrounding fluid directly or indirectly. For example, a miniature loudspeaker with this MEMS can generate a high sound pressure level relative to the surface area of ​​the MEMS. However, similarly, within the scope of the embodiments described herein, it may also be used as a micropump, ultrasonic transducer, or other MEMS-based applications due to its task of moving fluids.

[0211] The core aspects of the invention are summarized again below in other terms. In this regard, the embodiments address the structural limitations in existing etching processes, namely, the limitations of geometric resolution in volumetric processing methods such as electro-etching, photolithography, electroforming, nanoimprinting, polishing, or other SI-structured processes, such as the thinnest trench to be etched to represent field-driven effects, such as in-plane electrostatic or electromagnetic effects.

[0212] The Bosch Si structuring method limits the aspect ratio (depth to width) of the etched Si structure to a typical 30. In current variants of microspeakers (NED, muscle, comb-like), the structuring of electrostatically deflectable components (driving force) describing the fill factor of the area region, as well as the structuring of passive components (resistive structures, displacement components, fluid-resistant structures), is limited by the Bosch method. In microspeakers, driving force and fill factor are crucial for achieving a higher sound pressure level (SPL) / chip area (SPL / mm²). 2 The main parameters of ) are as follows. Therefore, a new, simpler drive version must be found that is not limited by the aspect ratio of the Bosch method and allows, for example, 100dB / mm. 2 Or higher.

[0213] The solution of this invention is described in Chapter 6 of this specification as an apparatus and method for deflecting one or more resistive components. This solution includes an apparatus comprising a MEMS acoustic transducer as a layer system. The core of this invention is:

[0214] - Increased Driving Force: The driving force of the new drive is no longer limited by the aspect ratio of the Bosch process. The basic idea is to achieve the electrode gap through a bonding process of at least two disks. Therefore, without the limitations of the Bosch process, the effective electrode gap can be set to be particularly small, and thus a large force can be generated. This gap is created between one disk to be bonded and another disk. The gap then separates the active moving component (e.g., a beam structure) in the first disk (device wafer) to be bonded from the other disk (cover wafer or substrate wafer) to be bonded. Therefore, a drive is generated across the gap along the periphery or a portion of the periphery of the active moving component.

[0215] - In one implementation (“cover drive”), the force is defined by the vertical distance from the top of the cover wafer or bottom wafer to the top of the device wafer. The distance between the cover wafer and the device wafer can be defined independently of the Bosch method, and therefore a larger aspect ratio or a larger driving force can be obtained by cover drive. Here, the drive is performed along the longitudinal edge at the top and / or bottom (as the upper and lower portions of the periphery) of the active movable component, which is the electrode side closest to the cover and / or bottom.

[0216] In one implementation (“face-driven”), the force between the active movable component (e.g., an elongated fin assembly) and the cover or substrate is determined by the lateral distance between two engaging disks. The two disks will at least partially engage with each other. Therefore, the drive occurs along the front side (the lateral portion of the periphery of the active movable structure). Advantageously, compared to cover-driven drive, an additional conductive layer can be omitted here.

[0217] - Several devices can be stacked together, that is, all disks have active deflectable components.

[0218] - Increasing the fill factor: The fill factor of a microspeaker is characterized, for example, by the maximum value between the fill factor of the actuator and the fill factor of the resistive structure in the shift plane (device plane). If the fill factors of both components of the microspeaker are limited, for example, by the Bosch method, it is difficult to arbitrarily increase the fill factor of the microspeaker. Therefore, it is important to make the fill factors of the actuator and the resistive structure independent of the Bosch method. In overlay drive, the fill factors of the actuator and resistive structure layers are independent of the Bosch method.

[0219] Compared to known prior art, the feature of overlay driving may be, for example, that a conductive layer is disposed between the overlay wafer and the layer containing the fluid-resistant components. Similarly, another conductive layer is disposed between the same layer containing the fluid-resistant components and the bottom wafer.

[0220] As used herein, a resistive component does not mean an electrical resistor, but rather a resistive component that interacts with the surrounding fluid, such as movable component 16. In other words, this resistive component may also be referred to as a displacement component, fin, or active or passive actuator.

[0221] The first and second electrical layers can be structured such that one or more separate voltages can be applied within the two electrical layers. If only one voltage is required (per cover wafer / bottom wafer) (depending on the application), the cover wafer or bottom wafer itself can be used as the first and second electrical layers.

[0222] If two or more voltages (per cover wafer / bottom wafer) are necessary (depending on the application), the following applies:

[0223] A first conductive layer and a second conductive layer are mechanically fixed to a layer on the top or bottom wafer via an insulating bonding layer. The main sides of these conductive layers face away from the corresponding adjacent layers on the top and bottom wafers and are mutually oriented. Another layer is disposed between the two main sides of the conductive layers, from which a cavity is formed using a SI structuring method. This cavity surrounds at least one resistive component relative to a plane parallel to the layers arranged to cover and dispose of the wafer. The resistive component, formed from a doped semiconductor material, subdivides the cavity into sub-cavities compared to the cavity itself using the SI structuring method.

[0224] Both linear and nonlinear operations can be achieved through overlay-driven mechanisms. Embodiments exhibiting linear deflection behavior differ from those exhibiting nonlinear deflection behavior. A preferred embodiment is the one with linear deflection behavior.

[0225] In other words, the overlay drive can be used to implement both a "balanced brake" (linear actuator) and an "unbalanced brake".

[0226] The meaning of "linear operation / linear deflection method / linear deflection behavior" of the "balanced brake" is as follows:

[0227] When a voltage is applied to the first and second conductive layers, an electrical force is generated between the conductive layers and the resistive component. When the voltage on all conductive layers is equal, the electrical forces are balanced and the resistive component does not move.

[0228] However, if the voltages within the first or second conductive layer are unequal (voltage 1 and voltage 2), an imbalance occurs, and the resistive components move linearly in one or the other direction. If voltage 1 and voltage 2 change in opposite phases (one increases and the other decreases), then two electrical forces 1 and 2 act on the resistive components in opposite directions, and thus one force increases and the other decreases. The resulting force (F1 + F2) is linearly related to the applied voltages 1 and 2, meaning that the movement of the resistive components is also linearly related to the voltages. The linearity between the applied electrical signal and the deflection of the resistive components affects the sound of the loudspeaker. The more linear the relationship, the lower the distortion factor. The more linear the relationship, the better the loudspeaker can reproduce sound.

[0229] The meaning of the nonlinear operation / nonlinear deflection method of the "unbalanced brake" is as follows:

[0230] - Only one force (not two forces) acts on the resistive component in a certain direction. This force is quadratic with respect to the voltage, or the movement of the resistive component is quadratic with respect to the voltage. That is, there is no linear correlation between the voltage and the movement of the resistive component. Therefore, the sound quality is affected. In other words, the distortion factor of the loudspeaker is significantly higher than that of a loudspeaker with a linearly driven acoustic transducer.

[0231] - "Unbalanced brakes" (nonlinear operation / nonlinear deflection methods) are generally easier to implement technically because only one voltage (rather than two or more) needs to be applied to the conductive layer. That is, there is no need to structure the conductive layer. In one embodiment, the conductive layer can even be omitted entirely, allowing the necessary voltage to be applied directly to the overlay wafer or the bottom wafer. In this case, the overlay wafer and the bottom wafer can be structured; see [link to relevant documentation]. Figures 8a to 8c .

[0232] Advantageously, the dense packaging that can be achieved in the core idea of ​​the present invention can be combined with microresonator structures to improve acoustic radiation in the low frequency range.

[0233] In other words, the electrodes and all corresponding sub-components are formed in one or more layers. Electrical insulation of the sub-electrodes is provided by spacers 28, which may contain, for example, oxides or nitrides, such as Si2O, Si3N4, or Al2O3.

[0234] The methods of controlling the resistance component and deflecting it and thus interacting with the surrounding fluid can be the same for different movable components suspended from one wafer or exposed from two wafers.

[0235] The advantages of coverage-driven architecture described in this article are:

[0236] 1. The force of the actuator can be controlled by the gap between the movable component and the bottom or overlay wafer during the bonding process between wafers, but is not determined by, for example, etching methods. This eliminates the limitation of the Bosch process, for example, to an aspect ratio of approximately 30. That is, actuators with an aspect ratio greater than 30 can be manufactured.

[0237] 2. Furthermore, the use of BSOI wafers can be eliminated. For cover wafers or bottom wafers, and for device wafers, layer 121, standardized Si wafers, can be used, which are much cheaper.

[0238] 3. Furthermore, compared to classic NED (nanoscale electrostatic drive) or comb-like drives, BSOI wafers, which are typically not machined from both sides to increase aspect ratio, can be used. In manufacturing the overlay drive described herein, both the BSOI wafer and the wafer can be machined from both sides, allowing the trenches between the resistive structures fabricated by the Bosch process to have double the aspect ratio, for example, 2 × 30, i.e., approximately 60. The aspect ratio can be further increased when multiple device wafers are bonded together, such as by, for example, bonding... Figure 15b and Figure 15c As described. For example, aspect ratios of 120 (two device wafers), 180 (three device wafers), 240 (four device wafers), etc., can be obtained.

[0239] 4. Since the fill factor of the actuator (see first advantage) and the fill factor of the device level (see previous advantages) can be independent of methods such as the Bosch method, the fill factor of the entire system, i.e., the number of actuators or resistance structure / area units, can be greatly improved.

[0240] a) Because the actuator portion, i.e. the electrode gap, is detached from the device plane (the core idea of ​​this invention), the mechanical and movable components in the device plane can be more densely packed, and thus the fill factor (number of actuators or resistance structures / area units) of the entire system can be advantageously and greatly improved (louder sound per unit area).

[0241] b) Furthermore, symmetrical systems with a height of half that of the device can be stacked, and therefore theoretically, the apparent aspect ratio can be increased without limitation. This is based on the absence of any support layers or similar structures relative to the device plane.

[0242] 5. A simple technique for devices and overlay / bottom wafers: Filled HR trenches cannot be used to achieve on-chip insulation (HR = high aspect ratio). No short circuits are expected within a single plane (between the resistive components and the overlay and bottom wafers). This significantly improves the yield of short-circuit-free chips that can be diced from the wafer.

[0243] 6. The final device of the embodiment consists only of Si and SiO2. An Al2O3 layer or other layers, which could induce stress in the system, are not required.

[0244] 7. The resistance structure is driven from both sides (top and bottom). The actuators are located symmetrically from both sides (top and bottom) along the entire length of the resistance structure. Compared to the case where the resistance structure is driven from only one side, the resistance structure will not oscillate.

[0245] 8. No electric field between resistive structures: The device wafer has the same potential everywhere -> no filtering effect.

[0246] 9. Si-SiO2 or SiO2-SiO2 can be directly bonded at 1000°C: 25 to 50 wafers can be bonded simultaneously in one furnace. This can lead to cost savings in the manufacturing process.

[0247] a. It can avoid lateral pull-in between resistive structures: all resistive structures have the same potential.

[0248] Although some aspects of the apparatus have been described, it should be understood that these aspects also represent a description of the corresponding method, such that blocks or components of the apparatus should also be understood as steps or features of the corresponding method steps. Similarly, aspects described in conjunction with or as steps of the method also represent descriptions of corresponding blocks, details, or features of the corresponding apparatus.

[0249] Depending on the specific implementation requirements, embodiments of the present invention may be implemented in hardware or software. This implementation may be performed using digital storage media such as floppy disks, DVDs, Blu-ray discs, CDs, ROMs, PROMs, EPROMs, EEPROMs, flash memory, hard disks, or any other magnetic or optical storage media storing electronically readable control signals that can interact with or be interacted with a programmable computer system to perform corresponding methods. Therefore, the digital storage media may be computer-readable. Accordingly, some embodiments of the present invention include a data carrier having electronically readable control signals capable of interacting with a programmable computer system to perform any of the methods described herein.

[0250] Generally, embodiments of the present invention can be implemented as a computer program product having program code that, when run on a computer, can operate to perform any method. For example, the program code can also be stored on a machine-readable medium.

[0251] Other embodiments include a computer program for performing any of the methods described herein, wherein the computer program is stored on a machine-readable medium.

[0252] In other words, an embodiment of the method according to the invention is therefore a computer program containing program code for performing any of the methods described herein when the computer program is run on a computer. Thus, another embodiment of the method according to the invention is a data carrier (or digital storage medium or computer-readable medium) on which a computer program for performing any of the methods described herein is recorded.

[0253] Therefore, another embodiment of the method according to the invention is a data stream or signal sequence constituting a computer program for performing any of the methods described herein. The data stream or signal sequence may, for example, be configured to be transmitted via a data communication link, such as via the Internet.

[0254] Another embodiment includes a processing means, such as a computer or a programmable logic device, configured or adapted to perform any of the methods described herein.

[0255] Another embodiment includes a computer having a computer program installed thereon for performing any of the methods described herein.

[0256] In some embodiments, a programmable logic device (e.g., a field-programmable gate array (FPGA)) may be used to perform some or all of the functions of the methods described herein. In some embodiments, the field-programmable gate array may interact with a microprocessor to perform any of the methods described herein. Generally, in some embodiments, the method is performed on a portion of any hardware device. This hardware device may be general-purpose hardware such as a computer processor (CPU) or method-specific hardware such as an ASIC.

[0257] The embodiments described above are merely illustrative of the principles of the invention. It should be understood that modifications and variations to the arrangements and details described herein will be readily apparent to those skilled in the art. Therefore, the invention is intended to be limited only by the scope of the following claims and not by the specific details presented in the description and explanation of the reference embodiments.

Claims

1. A MEMS device comprising: A layer stack (12) containing multiple MEMS layers arranged along the layer stack direction (14); A movable component (16) is formed in a first MEMS layer (121); the movable component is arranged between a second MEMS layer (122) and a third MEMS layer (123) of the layer stack (12). The driving unit (22) includes a first driving structure (22a) mechanically fixedly connected to the movable component (16) and a second driving structure (22b) mechanically fixedly connected to the second MEMS layer (122); The driving unit (22) is configured to generate a driving force (F) perpendicular to the layer stack direction (14) on the movable component (16), and the driving force (F) is configured to deflect the movable component. The MEMS device includes one of a MEMS speaker, a MEMS microphone, a MEMS micropump, and a MEMS ultrasonic transducer; The MEMS device includes a plurality of movable components arranged side-by-side in a common MEMS plane and fluidly or by means of coupling components coupled to each other. The plurality of movable components are adapted to interact with the fluid together to operate as the MEMS speaker, the MEMS microphone, the MEMS micropump, or the MEMS ultrasonic transducer.

2. The MEMS device according to claim 1, wherein the first driving structure (22a) and the second driving structure (22b) are spaced apart by a gap and arranged opposite each other; wherein the size of the gap along the layer stacking direction (14) is adjusted by a bonding process.

3. The MEMS device of claim 1, wherein the movable component comprises a plurality of layers joined by a bonding process.

4. The MEMS device of claim 1, wherein the first driving structure (22a) and the second driving structure (22b) are spaced apart by a gap and arranged opposite to each other; wherein the second driving structure (22b) is a structured electrode structure comprising at least a first electrode assembly and a second electrode assembly electrically insulated therefrom; the MEMS device is configured to apply a first potential to the first electrode assembly and apply a different second potential to the second electrode assembly; wherein the MEMS device is further configured to apply a third potential to the first driving structure (22a) to generate the driving force (F) in cooperation with the third potential and the first potential or the second potential.

5. The MEMS device according to claim 4, wherein the first electrode assembly and the second electrode assembly are electrically insulated from each other by an electrode gap (28), wherein the rest position of the movable component (16) is arranged symmetrically and / or asymmetrically opposite to the electrode gap (28).

6. The MEMS device of claim 4, wherein the movable component is a monolithic component and includes a single third potential.

7. The MEMS device according to claim 1, The cross-section of the movable component is polygonal, single-curve, or multi-curve; or The movable component has a variable dimension perpendicular to the layer stack direction (14) in a cross-section along the layer stack direction (14).

8. The MEMS device according to claim 1, wherein the electrodes of the second drive structure (22b) have variable lateral dimensions perpendicular to the axial direction along an axial path perpendicular to the layer stacking direction (14) to allow for consideration and / or compensation of mechanical stresses that may be induced by electrode deformation.

9. The MEMS device according to claim 1, The first driving structure (22a) is disposed between the movable component (16) and the second MEMS layer (122); the second driving structure (22b) is disposed between the first MEMS layer (121) and the second MEMS layer (122); the driving unit (22) includes a third driving structure (22c) mechanically fixedly connected to the third MEMS layer (123), wherein a first gap is disposed between the first driving structure (22a) and the second driving structure (22b), and a second gap is disposed between the first driving structure (22a) and the third driving structure (22c); The drive unit (22) is configured to provide the driving force (F) based on a first interaction between the first drive structure (22a) and the second drive structure (22b) and a second interaction between the first drive structure (22a) and the third drive structure (22c).

10. The MEMS device of claim 9, wherein the driving unit (22) is configured to generate a first driving force component based on the first interaction and a second driving force component based on the second interaction, and the MEMS device is configured to generate the first driving force component and the second driving force component that are in phase or have a phase shift.

11. The MEMS device of claim 1, wherein the movable component is mechanically connected to the third MEMS layer (123) via an elastic region (104); wherein the movable component is configured to perform rotational movement based on the driving force (F) when the elastic region (104) is deformed.

12. The MEMS device of claim 11, wherein the first driving structure is disposed on the front side of the movable component.

13. The MEMS device according to claim 1, wherein the electrode structure is arranged on one side facing the second MEMS layer (122) and / or facing the third MEMS layer (123), and forms at least a portion of the first driving structure (22a).

14. The MEMS device according to claim 1, wherein the movable component has a surface texture on the side facing the second MEMS layer (122) and / or the second MEMS layer (122) has a surface texture on the side facing the movable component (16) to locally change the distance between the movable component (16) and the second MEMS layer (122).

15. The MEMS device according to claim 1, wherein the electrodes of the first driving structure (22a) and / or the electrodes of the second driving structure (22b) are arranged and interconnected in an interdigitated manner.

16. The MEMS device of claim 1, wherein each of the plurality of movable components (16) is provided with a drive structure comprising at least two side-by-side connection electrodes, one of the at least two connection electrodes being connected to a first potential and the second electrode of the at least two connection electrodes being connected to a different second potential; wherein opposing electrodes adjacent to the movable components are connected to a combination of the first potential and the second potential.

17. The MEMS device according to claim 1, wherein the movable component is movably arranged in the MEMS cavity, wherein by means of movement of the movable component (16), the size of at least a sub-cavity of the cavity alternately expands and decreases, wherein the sub-cavities partially extend into the second MEMS layer (122).

18. The MEMS device of claim 1, wherein the movable component comprises a component length extending along an axial direction perpendicular to the layer stacking direction (14), wherein the electrodes of the first drive structure (22a) comprise a plurality of electrode segments along the component length, adjacent electrode segments being electrically connected to each other by an electrical conductor having a lower mechanical stiffness than the electrode segments along a direction perpendicular to the component length.

19. The MEMS device of claim 1, wherein the movable component is configured to provide interaction with a fluid.

20. The MEMS device according to claim 1, wherein the driving unit (22) includes a fourth driving structure (22d) disposed on the side of the second MEMS layer (122) opposite to the movable component (16), and other movable components are disposed adjacent to the fourth driving structure (22d) and form a stacked arrangement with the movable component (16).

21. A method of operating a MEMS device, comprising the following steps: Control (1910) two drive structures arranged along the layer stack direction, multiple MEMS layers of the MEMS device arranged along the layer stack direction, and The control generates (1920) a driving force perpendicular to the layer stack direction on the movable components of the MEMS device to deflect the MEMS device. The MEMS device includes one of a MEMS speaker, a MEMS microphone, a MEMS micropump, and a MEMS ultrasonic transducer. The MEMS device includes a plurality of movable components arranged side-by-side in a common MEMS plane and fluidly or by means of coupling components, wherein the plurality of movable components interact with the fluid together to operate as the MEMS speaker, the MEMS microphone, the MEMS micropump, or the MEMS ultrasonic transducer.

22. The method of claim 21, wherein the symmetric and / or linear deflection of the movable component (16) is controlled by means of a MEMS device of two adjacent electrode components by controlling the electrode components symmetrically with respect to a reference potential over time relative to the applied potential, the two adjacent electrode components being electrically insulated from each other by an electrode gap (28).

23. The method of claim 21, wherein the deflection of the movable component (16) is asymmetrically controlled over time along an actuation direction relative to the opposite direction.

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