Element for use in a micro-electro-mechanical system and micro-electro-mechanical system

Abstract

The invention relates to an element (100) for use in a micro-electro-mechanical system (200), in particular for use in semiconductor technology equipment, and to a micro-electro-mechanical system (200) comprising such an element (100). The element (100) comprises a MEMS structure (101) and at least one coating (140) applied over a large area to designated partial surfaces (135, 155) of the MEMS structure (101) from one side of the element (100), wherein the MEMS structure (100) has at least one otherwise non-functional special shape (160) with which at least a continuous parasitic coating (145) is avoided for certain areas away from the designated partial surfaces (135, 155).

Description

[0001] The invention relates to an element for use in a micro-electro-mechanical system, in particular for use in semiconductor technology equipment, and to a micro-electro-mechanical system comprising such an element.

[0002] In the prior art, semiconductor technology equipment refers to equipment used for the production or testing of microstructured devices or the components required for their manufacture. An example of such equipment is a projection exposure system for photolithography.

[0003] Photolithography is used to manufacture microstructured components, such as integrated circuits. The projection exposure system used comprises an illumination system and a projection system. The image of a mask (also called a reticulum) illuminated by the illumination system is projected in a reduced size onto a substrate, such as a silicon wafer, coated with a photosensitive layer and positioned in the image plane of the projection system. This transfers the mask structure onto the photosensitive coating of the substrate.

[0004] In illumination systems, particularly projection exposure systems designed for the EUV range (i.e., for exposure wavelengths from 5 nm (or possibly 2 nm) to 30 nm), but also for the DUV range with exposure wavelengths of, for example, 193 nm, two faceted mirrors are typically positioned in the beam path between the actual exposure radiation source and the mask to be illuminated. The faceted mirror closer to the exposure radiation source in the beam path is often a so-called field faceted mirror, while the other is a so-called pupil faceted mirror.

[0005] To produce different intensity and / or angle of incidence distributions when illuminating the mask, it is known to form the facets of at least one of the two faceted mirrors – in particular those of the field faceted mirror – from one or more individually electromechanically pivotable micromirrors. A corresponding method is disclosed, for example, in WO 2012 / 130768 A2.

[0006] In order to achieve a small size for the individual micromirrors, it is known to form groups of micromirrors in the form of a so-called MEMS mirror array, namely a mirror array made of micro-electro-mechanical systems (MEMS).

[0007] Micro-electro-mechanical systems (MEMS) are small components that combine micromechanical structures and electronic elements on a single chip. MEMS can be manufactured using integrated circuits, similar to microchips. A MEMS essentially comprises a basic structure on which movable elements, controlled relative to the basic structure, are arranged.

[0008] In a MEMS mirror array, a multitude of small mirror elements are mounted so that they can be moved individually relative to a common base structure. At least one actuator is provided for each mirror element, allowing it to be adjusted along a predefined degree of freedom. Often, the mirror elements can be pivoted about two axes perpendicular to each other and parallel to the base, and sufficient actuators are provided to allow the mirror elements to pivot independently about these axes. Sensors can also be provided for the individual mirror elements to determine their position relative to the base, thus enabling monitoring of the mirrors' alignment. A particularly advantageous embodiment for the mirrors of a MEMS mirror array is described in DE 10 2015 204 874 A1.

[0009] A method for manufacturing a micromirror or a MEMS mirror array comprising a plurality of such micromirrors is disclosed in DE 10 2015 220 018 A1, together with further details on a possible embodiment of the micromirror.

[0010] A crucial step in the fabrication of components for use in a micro-electromechanical system is the application of coatings to at least a portion of the component's or system's surfaces, ensuring complete coverage. These coatings can serve a variety of functions: for example, they can act as etch-stop layers or bonding layers for subsequent manufacturing processes, as protective layers against environmental influences, as electrically capacitive or dielectrically active layers, or—particularly in the case of micromirror components for semiconductor technology systems—as layers that reflect radiation within a specific wavelength range.

[0011] If, for technical or economic reasons, a coating is applied over a large area to an element at any point during or at the end of a manufacturing process using a partially isotropic deposition method, it is generally not only those areas that are coated for which the coating is required or desired that are coated. Rather, the coating material regularly also reaches other surfaces of the element and can even form a continuous coating there as well. Furthermore, the coating material can penetrate into cavities of the element and potentially clog them.

[0012] For example, the unintentional application of electrically conductive coatings to surfaces not intended for this purpose, such as those with electrical wires or connections, can lead to leakage currents or short circuits, thus impairing the functionality of the micro-electromechanical system. Similarly, an accumulation of coating material in a cavity required for the movement of a micro-electromechanical element can adversely affect the functionality of the element or the micro-electromechanical system. If the impairment of functionality is too severe, it results in scrap, which is often costly.

[0013] The object of the present invention is to create an element for use in a micro-electro-mechanical system in which, despite at least one large-area coating being applied, the aforementioned disadvantages and problems do not occur or only occur to a reduced extent.

[0014] This problem is solved by an element according to claim 1 and a micro-electro-mechanical system according to claim 11. Advantageous further developments are the subject of the dependent claims.

[0015] Accordingly, the invention relates to an element for use in a micro-electro-mechanical system, wherein the element comprises a MEMS structure and at least one coating applied over a large area to designated partial surfaces of the MEMS structure from one side of the element, wherein the MEMS structure has at least one otherwise non-functional special shape with which at least a continuous parasitic coating is avoided for certain areas away from the designated partial surfaces.

[0016] Furthermore, the invention relates to a micro-electro-mechanical system comprising an element according to the invention.

[0017] First, some terms used in connection with the invention will be explained.

[0018] An "element for use in a micro-electro-mechanical system" is an element that is at least partially integrated into the micro-electro-mechanical system, specifically where the "MEMS structure of the element" forms at least parts of the micro-electro-mechanical system. Thus, the element or its MEMS structure can be the micro-electro-mechanical system itself. If the micro-electro-mechanical system is composed of several components, the element or its MEMS structure can be one of these components. Alternatively, the element can also be a semi-finished product from which the final MEMS structure is formed through subsequent processing steps.

[0019] A "parasitic coating" is a coating that is not fundamentally necessary, but which cannot be avoided without further measures due to the coating method required for the actual desired coating of certain surfaces.

[0020] A coating is considered "applied over a large area" if its application is not limited by technical measures to the surfaces for which it was originally intended. Instead, an entire side of an element is coated with the coating material, accepting, or even necessarily accepting, the formation of parasitic coatings even outside the intended areas. Such coating methods typically involve a partially isotropic deposition method, whereby the coating material is deposited at every point on the element in a substantially constant spatial direction during the coating process. Typical methods for such large-area coatings include physical vapor deposition processes.

[0021] In the case of an “otherwise non-functional special design” within the meaning of the present invention, a deviation from the shape expected by a person skilled in the art, recognizable by the MEMS structure, has no other recognizable function apart from the desired function of preventing a continuous parasitic coating.

[0022] The special design according to the invention is characterized by the fact that both the special design and its function or the effect achieved thereby are immediately apparent after coating on the MEMS structure and usually even on the micro-electro-mechanical system in which the MEMS structure is used: Thus, the special design usually remains, and its function can be read directly from the arrangement of one or more coatings over the entire MEMS structure - regularly also on the micro-electro-mechanical system.

[0023] If the MEMS structure is an intermediate product in the manufacture of a micro-electro-mechanical system, which is further processed in such a way that no special shape and / or its function with regard to the coating is recognizable on the final micro-electro-mechanical system, the MEMS structure as an intermediate product nevertheless constitutes an object according to the invention.

[0024] The invention recognizes that the formation of parasitic coatings can be locally avoided by suitable special shaping(s) on an element for use in a micro-electro-mechanical system. This prevents at least the formation of a continuous parasitic coating—that is, a coating on a partial surface that directly connects two edge regions of the partial surface—since, according to the invention, such a coating is interrupted by a suitable special shaping. Such an interruption is sufficient, for example, if otherwise an electrically conductive parasitic coating would create an electrical connection between two regions of the MEMS structure, which would impair the functionality of the micro-electro-mechanical system of which the MEMS structure is a part.

[0025] Preferably, a special design can be such that parasitic coating of a specific sub-area of ​​the MEMS structure is essentially completely avoided. With such a special design, the accumulation of coating material in areas that could, for example, impair the mechanical functionality of the micro-electro-mechanical system of which the MEMS structure is a part, can be prevented. Clear spaces that are intended and required for the desired movement within the micro-electro-mechanical system can thus be reliably kept clear.

[0026] At least one special feature can be designed to create a shadow for the area behind it, so that when a large area of ​​one side of the MEMS structure is coated, the shaded area remains uncoated. Such shading can prevent the formation of a continuous parasitic coating, provided that the shading prevents the coating of a partial area that would directly connect two edge regions of the partial area. If the shading feature is appropriately designed, the deposition of coating material in areas where such deposition is generally undesirable can be completely avoided or at least significantly reduced.

[0027] At least one special shading feature can be formed by a projection on the MEMS structure. In other words, a protrusion is provided on the MEMS structure that acts as a "shield" for an area behind it in the direction in which the coating is applied at that point. This area is then considered shaded. A projection also makes it possible, in particular, to shade an area where little or no coating material is desired.

[0028] Alternatively, at least one shading feature can be formed by an indentation in the MEMS structure. With such an indentation, a surface extending in the direction of the indentation's depth is shaded by an opposing surface. With a suitable design, an indentation can, in particular, prevent the formation of a continuous parasitic coating.

[0029] At least one special configuration can also be a step in the MEMS structure with such an abrupt transition that the end face of the step – i.e., the surface parallel to the step in the vertical direction – remains uncoated. If a surface that would otherwise be continuously coated has a step larger than the coating thickness, the two sub-surfaces on either side of the step will indeed be coated; however, if the end face of the step remains uncoated as required, the two coatings of the sub-surfaces are not bonded together, so the coating as a whole is not continuous.

[0030] To ensure that the end face remains free of coating, it is preferred that the end face is aligned parallel to the direction in which the coating material is applied in the step area or has an overhang. The overhang refers to the direction in which the coating material is applied in the step area. With such a design, it is ensured that the coating material does not directly contact the end face during the coating process, and therefore no coating forms there.

[0031] It is possible that two steps are formed on either side of a central projection in the MEMS structure. If a central projection is formed, it is ensured that, depending on the direction in which the coating material is applied in the area of ​​the projection, at least one of the two steps will not be coated.

[0032] It is also possible to form two steps on either side of a central recess in the MEMS structure. Analogous to a central projection, this generally ensures that the end face of at least one of the two steps remains coating-free. It is also possible to design both steps of a central recess with an overhang. In this case, it can generally be ensured that the end faces of both steps are coating-free.

[0033] The element can be a basic structure for a micro-electro-mechanically movable element, preferably a micromirror, particularly for semiconductor technology equipment, as well as a micro-electro-mechanically movable element, preferably a micromirror, particularly for semiconductor technology equipment. It is also possible that the element is a corresponding basic structure with a micro-electro-mechanically movable element, preferably a micromirror for semiconductor technology equipment, arranged thereon. Finally, it is also possible that the element is an array of micro-electro-mechanically movable elements, preferably micromirrors for semiconductor technology equipment, arranged on a common basic structure.

[0034] For an explanation of the micro-electro-mechanical system according to the invention, reference is made to the preceding statements.

[0035] The invention will now be described by way of example with reference to advantageous embodiments and the accompanying drawings. These show: Fig. 1: a schematic representation of a projection exposure system for photolithography comprising a micro-electro-mechanical system according to the invention with an element according to the invention; Fig. 2a, b: schematic representation of a micro-electro-mechanical system according to the prior art and according to the invention for use in the projection exposure system according to Fig. 1; and Fig. 3a-h: schematic representation of various embodiments of a further element according to the invention

[0036] In Fig. Figure 1 shows a projection exposure system 1 for photolithography as an example of a system for semiconductor technology in a schematic meridional section. The projection exposure system 1 comprises an illumination system 10 and a projection system 20.

[0037] The illumination system 10 illuminates an object field 11 in an object plane or reticulum plane 12. The illumination system 10 comprises an exposure radiation source 13, which, in the illustrated embodiment, emits illumination radiation comprising at least useful light in the EUV range, i.e., in particular with a wavelength between 5 nm and 30 nm. The exposure radiation source 13 can be a plasma source, for example, an LPP source (laser-produced plasma) or a DPP source (gas-discharge-produced plasma). It can also be a synchrotron-based radiation source. The exposure radiation source 13 can also be a free-electron laser (FEL).

[0038] The illumination radiation emanating from the light source 13 is first focused in a collector 14. The collector 14 can be a collector with one or more ellipsoidal and / or hyperboloid reflective surfaces. The at least one reflective surface of the collector 14 can be illuminated at grazing incidence (GI), i.e., with angles of incidence greater than 45°, or at normal incidence (NI), i.e., with angles of incidence less than 45°. The collector 14 can be structured and / or coated to optimize its reflectivity for the useful radiation and to suppress stray light.

[0039] After the collector 14, the illumination radiation propagates through an intermediate focus in an intermediate focal plane 15. If the illumination system 10 is to be constructed in a modular manner, the intermediate focal plane 15 can, in principle, be used for the separation – including structural separation – of the illumination system 10 into a radiation source module, comprising the exposure radiation source 13 and the collector 14, and the illumination optics 16 described below. With such a separation, the radiation source module and the illumination optics 16 then together form a modularly constructed illumination system 10.

[0040] The illumination optics 16 include a deflecting mirror 17. The deflecting mirror 17 can be a flat deflecting mirror or, alternatively, a mirror with an effect that influences the beam shape beyond the mere deflection effect. Alternatively or additionally, the deflecting mirror 17 can be designed as a spectral filter that separates a useful wavelength of the illumination radiation from stray light of a different wavelength.

[0041] The deflecting mirror 17 deflects the radiation from the illumination radiation source 13 onto a first faceted mirror 18. If the first faceted mirror 18 is arranged – as in the present case – in a plane of the illumination optics 16 that is optically conjugate to the reticular plane 12 as a field plane, it is also referred to as a field faceted mirror.

[0042] The first faceted mirror 18 comprises a plurality of micromirrors 18' that can be individually pivoted about two mutually perpendicular axes for the controllable formation of facets, each preferably equipped with an orientation sensor (not shown) for determining the orientation of the micromirror 18'. The first faceted mirror 18 is thus a microelectromechanical system (MEMS system), as described, for example, in DE 10 2008 009 600 A1.

[0043] In the beam path of the illumination optics 16, a second faceted mirror 19 is arranged downstream of the first faceted mirror 18, resulting in a double-faceted system, the basic principle of which is also known as a honeycomb condenser (fly's eye integrator). If the second faceted mirror 19 is arranged in a pupil plane of the illumination optics 16 – as in the illustrated embodiment – ​​it is also referred to as a pupil faceted mirror. However, the second faceted mirror 19 can also be arranged at a distance from a pupil plane of the illumination optics 16, in which case the combination of the first and second faceted mirrors 18, 19 results in a specular reflector, as described, for example, in US 2006 / 0132747 A1, EP 1 614 008 B1, and US 6,573,978.

[0044] The second faceted mirror 19 need not be constructed from pivotable micromirrors, but can instead comprise individual facets formed from one or a manageable number of mirrors that are significantly larger than micromirrors, and which are either fixed or tiltable only between two defined end positions. However, as shown, it is also possible to provide the second faceted mirror 19 with a microelectromechanical system comprising a plurality of micromirrors 19' that are individually pivotable about two axes perpendicular to each other, each preferably including an orientation sensor.

[0045] With the aid of the second faceted mirror 19, the individual facets of the first faceted mirror 18 are projected onto the object field 11, although this is regularly only an approximate projection. The second faceted mirror 19 can be the last beam-shaping or even the last mirror for the illumination radiation in the beam path before the object field 11.

[0046] Each of the facets of the second faceted mirror 19 is assigned to exactly one of the facets of the first faceted mirror 18 to form an illumination channel for illuminating the object field 11. This can result in illumination according to Köhler's principle.

[0047] The facets of the first faceted mirror 18 are each superimposed by a corresponding facet of the second faceted mirror 19 to illuminate the object field 11. The illumination of the object field 11 is as homogeneous as possible. It preferably exhibits a uniformity error of less than 2%. Field uniformity can be achieved by superimposing different illumination channels.

[0048] By selecting the illumination channels ultimately used, which is easily achieved by appropriately adjusting the micromirrors 18' of the first faceted mirror 18, the intensity distribution in the entrance pupil of the projection system 20 described below can also be adjusted. This intensity distribution is also referred to as the illumination setting. Furthermore, it can be advantageous not to arrange the second faceted mirror 19 exactly in a plane that is optically conjugate to a pupil plane of the projection system 20. In particular, the pupil faceted mirror 19 can be tilted relative to a pupil plane of the projection system 20, as described, for example, in DE 10 2017 220 586 A1.

[0049] During the Fig. In the arrangement of the components of the illumination optics 16 shown in Figure 1, the second faceted mirror 19 is arranged in a surface conjugate to the entrance pupil of the projection system 20. Deflection mirror 17 and the two faceted mirrors 18, 19 are arranged at an angle both to the object plane 12 and to each other.

[0050] In an alternative embodiment of the illumination optics 16, not shown, a transmission optic comprising one or more mirrors can be provided in the beam path between the second faceted mirror 19 and the object field 11. The transmission optic can, in particular, comprise one or two mirrors for normal incidence (NI mirrors) and / or one or two mirrors for grazing incidence (GI mirrors). With an additional transmission optic, different positions of the entrance pupil for the tangential and sagittal beam paths of the projection system 20 described below can be accommodated.

[0051] Alternatively, it is possible that on the in Fig. The deflecting mirror 17 shown in Figure 1 is dispensed with, for which the faceted mirrors 18, 19 are then to be arranged appropriately opposite the radiation source 13 and the collector 14.

[0052] Using the projection system 20, the object field 11 in the reticulum plane 12 is transferred to the image field 21 in the image plane 22.

[0053] The projection system 20 comprises a plurality of mirrors M. i , which are numbered according to their arrangement in the beam path of the projection exposure system 1. Regarding the mirrors M i These are optical elements 25.

[0054] In the Fig. In the example shown, the projection system 20 comprises six mirrors M1 to M6 as optical elements 25. Alternatives with four, eight, ten, twelve or another number of mirrors M iare also possible. The penultimate mirror M5 and the last mirror M6 each have a passage for the illumination radiation, making the depicted projection system 20 a doubly obscured optic. The projection system 20 has an image-side numerical aperture that is greater than 0.3 and can also be greater than 0.6, for example, 0.7 or 0.75.

[0055] The reflective surfaces of the mirrors M i can be designed as freeform surfaces without an axis of rotational symmetry. Alternatively, the reflective surfaces of the mirrors M can be i but can also be designed as aspherical surfaces with exactly one axis of rotational symmetry of the reflecting surface shape. The mirrors M iLike the mirrors of the lighting optics 16, they can have highly reflective coatings for the illumination radiation. These reflective coatings can be designed as multilayer coatings, in particular with alternating layers of molybdenum and silicon.

[0056] The projection system 20 has a large object-image offset in the y-direction between a y-coordinate of the center of the object field 11 and a y-coordinate of the center of the image field 21. This object-image offset in the y-direction can be approximately as large as a z-distance between the object plane 12 and the image plane 22.

[0057] The projection system 20 can in particular be anamorphic, i.e. it has in particular different image scales β x , β y in the x and y directions. The two image scales β x , β y of the projection system 20 are preferably located at (β x , βy ) - (+ / - 0.25, / +- 0.125). A magnification β of 0.25 corresponds to a reduction in the ratio of 4:1, while a magnification β of 0.125 results in a reduction in the ratio of 8:1. A positive sign for the magnification β indicates a magnification without image inversion, a negative sign indicates a magnification with image inversion.

[0058] Other magnification ratios are also possible. Magnification ratios with the same sign and those with the same absolute value β are also possible. x , β y In the x and y directions, adjustments are possible.

[0059] The number of intermediate image planes in the x- and y-directions in the beam path between the object field 11 and the image field 21 can be the same or different, depending on the design of the projection system 20. Examples of projection systems 20 with different numbers of such intermediate images in the x- and y-directions are known from US 2018 / 0074303 A1.

[0060] Projection system 20 can, in particular, have a homocentric entrance pupil. This may be accessible. However, it may also be inaccessible.

[0061] A reticle 30 (also called a mask) arranged in the object field 11 is exposed by the lighting system 10 and transferred to the image plane 21 by the projection system 20. The reticle 30 is held by a reticle holder 31. The reticle holder 31 can be moved, particularly in a scanning direction, by means of a reticle displacement drive 32. In the illustrated embodiment, the scanning direction is in the y-direction.

[0062] The reticle 30 can have an aspect ratio between 1:1 and 1:3, preferably between 1:1 and 1:2, and particularly preferably 1:1 or 1:2. The reticle 30 can be substantially rectangular and is preferably 5 to 7 inches (12.70 to 17.78 cm) long and wide, more preferably 6 inches (15.24 cm) long and wide. Alternatively, the reticle 30 can be 5 to 7 inches (12.70 to 17.78 cm) long and 10 to 14 inches (25.40 to 35.56 cm) wide, and is preferably 6 inches (15.24 cm) long and 12 inches (30.48 cm) wide.

[0063] A structure on the reticulum 30 is imaged onto a photosensitive layer of a wafer 35 located in the image plane 22 within the image field 21. The wafer 35 is held by a wafer holder 36. The wafer holder 36 can be displaced, particularly along the y-direction, via a wafer transfer drive 37. The displacement of the reticulum 30 via the reticulum transfer drive 32 and of the wafer 35 via the wafer transfer drive 37 can be synchronized.

[0064] The in Fig. The projection exposure system 1 shown in Figure 1, or its projection system 20, the above description of which essentially reflects known prior art, is characterized in that the first and second faceted mirrors 18, 19 comprise a micro-electro-mechanical system 200 according to the invention with elements 100 according to the invention.

[0065] In Fig. Figure 2 shows a schematic representation of such an electro-mechanical system 200 with elements 100 according to the invention, wherein Fig. 2a shows the state of the art, while in Fig. 2b shows the embodiment according to the invention.

[0066] The elements 100 according to the invention comprise the complete MEMS structure 101 of the micro-electro-mechanical system 200, comprising a base structure 110 with a mirror plate 130 movably arranged thereon via a joint arrangement 120. Electrical elements (not shown), such as conductor tracks, actuators or sensors, are arranged on the top side of the base structure 110 in order to control the MEMS structure or to determine measured values.

[0067] A reflective coating 140 is applied to the upper surfaces of the mirror plates 130, which are designated partial surfaces 135 of the MEMS structure 101. The coating 140 was applied over a large area to the MEMS structure 101 from one side of the element 100 by physical vapor deposition. The direction in which the coating material 140 was applied is indicated by the arrows 90: Essentially, the coating 140 is applied in a direction perpendicular to the element 100 or to the base structure 110 of the MEMS structure 101, although deviations of several ±10° may occur due to the isotropic component.

[0068] As in Fig. As can be seen in Figure 2a, part of the material of the coating 140 passes through the space between two mirror plates 130, so that a parasitic coating 145 forms on the base structure 110. In particular, if the coating 140, 145 is electrically conductive, the parasitic coating 145 can disrupt, and in particular short-circuit, the electrical elements arranged on the base structure 110.

[0069] To reduce or completely avoid the problems caused by the parasitic coating 145, the following is recommended: Fig. 2a Element 100 shown according to the state of the art in Fig. 2b is shown in a further developed embodiment according to the invention.

[0070] The element 100 according to the invention is characterized in that the MEMS structure 101 has otherwise non-functional special features 160 with which the parasitic coating 145 on the base structure 110 of the MEMS structure 101 can be at least significantly reduced, and in certain partial areas even substantially avoided.

[0071] Thus, projections 161 are provided around the sides of the mirror plates 130 to reduce the gap between them without restricting their movement. These projections 161 are set back from the partial surfaces 135 on the mirror plates 130 intended for the coating 140, such that any coating material 140 deposited on them is irrelevant to the reflection properties of the mirror plate 130, which are primarily determined by the coating 140. Consequently, it is immediately apparent to a specialist that the projections 161 serve solely to reduce the parasitic coating 145 on the base structure 110 and have no other function.

[0072] As on the left side of the Fig. Figure 2b shows the parasitic coating 145 that occurs on the base structure 110 during the coating process, in comparison to the prior art according to Fig. 2a significantly reduced.

[0073] Should this reduced parasitic coating 145 also prove undesirable or problematic, for example, due to the electrical conductivity of the coating material 140, an additional special feature 160 can be provided on the base structure 110. This feature is arranged on the upper surface and any conductor tracks present there, and is designed such that any material passing between the projections 161 on the mirror plates 130 during coating is deposited exclusively on this otherwise non-functional special feature 160. A corresponding feature is shown on the right side in Fig. 2b shown.

[0074] In Fig. Figure 3 shows various further embodiments of another element 100 according to the invention. The element 100 comprises a MEMS structure 101, which in subsequent post-processing is itself further developed into a complete micro-electro-mechanical system or is used as a component in a micro-electro-mechanical system.

[0075] The MEMS structure 101 has a base structure 110 on which electrodes 150 are arranged. The electrodes 150 are to be provided with a coating 140 on the end face 155 facing away from the base structure 110; in this case, the coating is also electrically conductive. At the same time, it must be ensured that the electrodes 150 are not electrically connected to each other, or at least not unintentionally so.

[0076] In order to prevent the parasitic coating 145, which inevitably results on the base structure 110 during the coating of the end faces 155 of the electrodes 150, from extending completely or continuously between two adjacent electrodes 150 and thereby electrically connecting them, the elements 100 are designed according to Fig. Three different measures according to the invention are shown to avoid such a continuous parasitic coating 145.

[0077] In the version according to Fig. 3a There are projections 161 on the electrodes 150 each, comparable to those from Fig. 2b is provided as a shading and otherwise non-functional special form 160. The projections 161 shade the area behind them on the base structure 110, so that no coating forms there during the coating of the end faces 155 of the electrodes 150. The parasitic coating 145 on the base structure 110 therefore does not extend to the individual electrodes 150, which is why they are not electrically connected to each other by the parasitic coating 145.

[0078] Even at Fig. 3b provides for corresponding cantilevers 161. However, these cantilevers 161 have a different shape than those shown. Fig. 3a. Here too, the parasitic coating 145 does not connect the two electrodes 150. Furthermore, apart from the desired coating 140 on the end faces 155, no other material of the coating 140 remains in contact with the electrodes 150, so that their electrical properties, in particular their capacitive properties, are not unintentionally altered by the accumulation of material of the coating 140.

[0079] In the version according to Fig. 3c also uses the principle of shading the base structure 110 to prevent a continuous parasitic coating 145 from forming on it. However, no overhang 161 is required for this purpose (cf. Fig. 3a, Fig. 3b), but rather an indentation 162 in the MEMS structure 101, here in the electrodes 150 themselves, is provided as a shading and otherwise non-functional special feature 160. The indentation 162 is designed such that the parasitic coating 145 on the base structure 110 does not come into contact with the electrodes 150. At the same time, the indentations 162 are designed such that neither the structural integrity nor the functionality of the electrodes 150 is impaired.

[0080] In the version according to Fig. In Figure 3d, the electrodes 150 of the MEMS structure 101 are shown without any special shape 160. Instead, a central projection 163 is provided on the base structure 110 as an otherwise non-functional special shape 160. On both sides of the projection 163, steps 165 are formed in the MEMS structure 101, the end faces 166 of which remain uncoated even after the end faces 155 of the electrodes 150 have been coated, since they are essentially parallel to the direction in which the material for the coating 140 is applied. Because the projection 163 has a height greater than the thickness of the coating 140 and thus also of the parasitic coating 145, the parasitic coating 145 is not continuous.

[0081] The in Fig. The principle described in 3d also applies to the execution variant according to Fig. 3e is used. However, no projection 163 on the basic structure 110 is provided here (cf. Fig. 3d), but rather a central recess 164 as an otherwise non-functional special shape 160, in which, however, two steps 165 also result in the MEMS structure 101, the end faces 166 of which remain coating-free.

[0082] In order to ensure the latter even in the case of a deviation from an ideal direction for the application of coating 140, the following applies to the execution variant according to Fig. 3f is designed by means of a central setback 164 as an otherwise non-functional special form 160, with steps 165 with an overhang 167.

[0083] The design variants according to Fig. 3g and Fig. 3h are based on those according to Fig. 3D and Fig. 3e, wherein, however, several projections 163 or recesses 164 are provided, which – analogous to the one described above – form a plurality of steps 165. The distance between the projections 163 or the width of the recesses 164 is to be selected such that the applied coating 140 does not, in principle, span any gap between two projections 163 or any recess 164. Typically, the aspect ratio – i.e., the ratio of depth to width – of the aforementioned gaps or recesses 164 is significantly greater than 1. The gaps or recesses 164 can be configured similarly to the embodiment shown in [reference to embodiment]. Fig. 3f should be designed with overhangs. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] WO 2012 / 130768 A2

[0005] DE 10 2015 204 874 A1

[0008] DE 10 2015 220 018 A1

[0009] DE 10 2008 009 600 A1

[0042] US 2006 / 0132747 A1

[0043] EP 1 614 008 B1

[0043] US 6,573,978

[0043] DE 10 2017 220 586 A1

[0048] US 2018 / 0074303 A1

[0059]

Claims

[1] Element (100) for use in a micro-electro-mechanical system (200), wherein the element (100) comprises a MEMS structure (101) and at least one coating (140) applied over a large area to designated partial surfaces (135, 155) of the MEMS structure (101) from one side of the element (100), characterized by , that the MEMS structure (100) has at least one otherwise non-functional special shape (160) which avoids at least a continuous parasitic coating (145) for certain areas away from the intended partial surfaces (135, 155). [2] Element according to claim 1, characterized by , that the special shape (160) essentially completely avoids a parasitic coating (145) of a certain partial surface of the MEMS structure (101). [3] Element according to any of the preceding claims, characterized by, that at least one special shape (160, 161, 162) is formed to create a shadow for a behind it, so that when a large area of ​​one side of the MEMS structure (101) is coated, the shadowed area remains uncoated. [4] Element according to claim 3, characterized by , that at least one shading special feature (160) is formed by a projection (161) on the MEMS structure (101). [5] Element according to claim 3 or 4, characterized by , that at least one shadowing special shape (160) is formed by an indentation (162) in the MEMS structure (101). [6] Element according to any one of the preceding claims, characterized by , that at least one special shape (160) includes a step (165) in the MEMS structure (101) with such an abrupt transition that the end face (166) of the step (165) is coating-free. [7] Element according to any one of the preceding claims, characterized bythat at least one step (165) is aligned parallel to the direction in which the coating material (140) is applied in the area of ​​the step (165) or is formed with an overhang (167). [8] Element according to any one of the preceding claims, characterized by , that two stages (165) are formed on both sides of a central projection (163) in the MEMS structure (101). [9] Element according to any one of the preceding claims, characterized by , that two stages (165) are formed on both sides of a central return (164) in the MEMS structure (101). [10] Element according to any one of the preceding claims, characterized by, that the element (100) is the basic structure (110) for a micro-electro-mechanically movable element, preferably a micromirror, a micro-electro-mechanically movable element, preferably a micromirror, a corresponding basic structure (110) with a micro-electro-mechanically movable element arranged thereon, preferably a micromirror, or an array of micro-electro-mechanically movable elements, preferably micromirrors, arranged on a common basic structure (110). [11] Micro-electro-mechanical system (200) comprising at least one element (100) according to any one of the preceding claims.

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