Element for use in a microelectromechanical system, and microelectromechanical system

Abstract

The invention relates to an element (100) for use in a microelectromechanical system (200), in particular for use in systems for semiconductor technology, and to a microelectromechanical system (200) comprising such an element (100). The element (100) comprises a MEMS structure (101) having a base structure (110) and at least one mirror plate (130) of a micromirror, which mirror plate can be moved microelectromechanically relative to the base structure, wherein at least one designated partial surface (135) of the at least one mirror plate (130) has a coating (140) that is applied over a large area from one side of the element (100), wherein the at least one mirror plate (130) has at least one otherwise functionless special formation (160) by means of which parasitic coating (145) is avoided in certain regions outside the designated partial surfaces (135).

Description

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

[0001] The present application claims priority over German patent application 102024 206 218.9, filed on July 2, 2024. The content of that German patent application is incorporated into the present application text by reference.

[0002] 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.

[0003] In the prior art, semiconductor technology equipment refers to equipment used for the manufacture or testing of microstructured devices or the components required for their production. An example of such equipment is a projection exposure system for photolithography.

[0004] 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, for example a silicon wafer, coated with a photosensitive layer and positioned in the image plane of the projection system, in order to transfer the mask structure onto the photosensitive coating of the substrate.

[0005] In lighting systems, especially 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 usually arranged in the beam path between the actual exposure radiation source and the mask to be illuminated. The faceted mirror located closer to the source of the light source in the beam path is often a so-called field faceted mirror, while the other is a so-called pupil faceted mirror.

[0006] 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 facet mirrors – in particular those of the field facet mirror – from one or more individually electromechanically pivotable micromirrors. A corresponding method is disclosed, for example, in WO 2012 / 130768 A2.

[0007] 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).

[0008] 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.

[0009] In a MEMS mirror array, a multitude of small mirror elements are mounted so that they can be individually moved 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 102015 204 874 A1.

[0010] A method for manufacturing a micromirror or a MEMS mirror array comprising a plurality of such micromirrors is disclosed - together with further details on a possible design of the micromirror - in DE 102015 220 018 A offenbart.

[0011] A crucial step in the production of elements for use in a microelectromechanical system is the application of coatings to at least a portion of the element's or system's surfaces, ensuring complete coating 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, protective layers against environmental influences, electrically capacitive or dielectrically active layers, or—particularly in the case of micromirror elements—for... Systems for semiconductor technology - at least for radiation in a specified wavelength range, form reflective layers.

[0012] 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.

[0013] 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-electro-mechanical system. Similarly, an accumulation of coating material in a cavity required for the movement of a micro-electro-mechanical element can adversely affect the functionality of the element or the micro-electro-mechanical system. If the impairment of functionality is too significant, it results in scrap, which is often costly.

[0014] 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.

[0015] This problem is solved by an element according to claim 1 and a micro-electro-mechanical system according to claim 14. Advantageous further developments are the subject of the dependent claims.

[0016] Accordingly, the invention relates to an element for use in a micro-electro-mechanical system, wherein the element comprises a MEMS structure with a basic structure and at least one of the mirror plates of a micromirror that are movable relative to the micro-electro-mechanical system, wherein at least one of the mirror plates has a coating applied over a large area from one side of the element to a portion of the mirror plate provided for this purpose, wherein the mirror plate has at least one otherwise non-functional special shape with which at least a parasitic coating is avoided for certain areas away from the portions provided for this purpose.

[0017] Furthermore, the invention relates to a micro-electro-mechanical system comprising an element according to the invention.

[0018] First, some terms used in connection with the invention will be explained.

[0019] An "element for use in a micro-electromechanical system" is an element that is at least partially found within the micro-electromechanical system, specifically where the "MEMS structure of the element" forms at least parts of the micro-electromechanical system. Thus, the element or its MEMS structure can be the micro-electromechanical system itself. If the micro-electromechanical system is composed of several components, the element can be one of these components. The element, or rather its MEMS structure, may be one of these components of the micro-electro-mechanical system. However, the element may also be a semi-finished product from which the final MEMS structure is formed through subsequent processing steps.

[0020] A "parasitic coating" is a coating that is not fundamentally necessary, but which cannot be avoided without further measures due to the coating method used for the actual desired coating of certain surfaces.

[0021] 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 employ 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 (PVD) processes.

[0022] 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 in the MEMS structure, which, apart from the desired function of preventing a continuous The parasitic coating has no other discernible function.

[0023] 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, whereby 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.

[0024] 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 in the final micro-electro-mechanical system, the MEMS structure as an intermediate product nevertheless constitutes an object according to the invention.

[0025] The invention recognizes that, through suitable special shaping(s) on an element for use in a micro-electro-mechanical system, the formation of parasitic coatings can be locally avoided. By locally avoiding parasitic coatings, depending on the design of the MEMS structure, an electrical connection between two areas of the MEMS structure, which would otherwise be created by a parasitic electrically conductive coating and could impair the functionality of the micro-electro-mechanical system of which the MEMS structure is a part, can be prevented.

[0026] 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 mobility within the micro-electro-mechanical system can thus be reliably kept clear.

[0027] 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 a shadow can prevent the formation of a continuous parasitic coating, provided that the shadow 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 material deposition is generally undesirable can be completely avoided or at least significantly reduced.

[0028] In this case, at least one special shading feature is preferably formed by a projection on a mirror plate. In other words, a projection is provided on a mirror plate, which acts as a "shield" for a component in the The direction in which the coating is applied at this point, and the area behind it. This area is then considered shaded. A cantilever also allows, in particular, the Shading of an area where little or no coating material is desired. The overhang is to be provided, in particular, on one or more sides of the mirror plate.

[0029] If the element comprises at least two mirror plates, it is preferred that at least two adjacent mirror plates each have projections on their facing sides to create a shadow for an area behind them. A gap is regularly provided between two adjacent mirror plates so that the mirror plates can be moved individually, in particular pivoted. The projections on the facing sides ultimately reduce this gap, thus preventing coating material from passing through it.

[0030] The projections on adjacent mirrors must be designed so that, even after a large-area coating has been applied and coating material may be adhering to it, they do not restrict the movement of the mirror plates. Therefore, a residual gap must always be provided between the projections. To minimize this residual gap, it is preferred that at least one projection be arranged in a plane through the pivot point of the mirror plate, around which the mirror plate can pivot. This ensures that this projection does not deflect, regardless of the movement of the mirror plate, but moves exclusively along a radius around the pivot point. If two adjacent mirror plates are designed accordingly, the gap remaining between the respective projections can be reduced to a minimum.The same applies to the gap between a movable mirror plate and a stationary structure.

[0031] In addition to a special, otherwise non-functional design provided on a mirror plate, which is intended to prevent parasitic coating in certain areas away from the designated partial surfaces, areas affected by parasitic coating away from the mirror plate may nevertheless have other suitable special design(s) in order to at least reduce the negative effects of parasitic coatings.

[0032] In particular, a special shape located away from the mirror plate can, in principle, be comparable to a special shape on the mirror plate, i.e., also designed as a cantilever. With a suitable design of the cantilever and the resulting shading, the formation of a continuous parasitic coating – i.e., a coating of a partial surface with which two edge areas of the partial surface are directly connected – can be avoided.

[0033] Alternatively, at least one special shading feature can be formed away from the mirror plate by means of 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.

[0034] At least one special shape, apart from the mirror plate, 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's vertical direction – remains uncoated. If a surface without a corresponding step is continuously coated... If the coating thickness were increased by one step, the two sub-surfaces on both sides of the step would be coated; however, if the end face of the step remains uncoated as required, the two coatings of the sub-surfaces are not connected to each other, so that the coating as a whole is not continuous.

[0035] To ensure that the end face of such a step remains free of coating, it is preferred that the end face is aligned parallel to the direction in which the coating material is applied to the step or has an overhang. The overhang refers to the aforementioned direction in which the coating material is applied to the step. 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.

[0036] It is possible that two steps are formed on either side of a central protrusion in the MEMS structure. If a central protrusion is formed, it is ensured that, depending on the direction in which the coating material is applied in the area of ​​the protrusion, at least on the end face of one of the two steps no coating is formed.

[0037] It is also possible to form two steps on either side of a central recess in the MEMS structure. This, analogous to a central projection, generally ensures that the end face of at least one of the two steps remains coating-free. It is possible to design both steps of a central recess with an overhang. In this case, it can generally be ensured that... Ensure that the end faces of both steps are free of coating.

[0038] The element in question could be a component for semiconductor technology equipment. In particular, it is also possible that the element is an array of micro-electromechanically movable micromirrors arranged on a common base structure, especially for semiconductor technology equipment.

[0039] For an explanation of the micro-electro-mechanical system according to the invention, reference is made to the preceding statements.

[0040] The invention will now be described by way of example with reference to advantageous embodiments and the accompanying drawings. These show: Figure 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; Figure 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 Figure 1; Figure 3: Schematic representation of a further micro-electro-mechanical system according to the invention for use in the projection exposure system according to Figure 1; and Figure 4a-h: schematic representation of various embodiments of special designs according to the invention other than a mirror plate.

[0001] 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.

[0002] An object field 11 in an object plane or reticulum plane 12 is illuminated by means of the illumination system 10. The illumination system 10 comprises an exposure radiation source 13, which, in the illustrated embodiment, emits at least some 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).

[0003] 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 oriented with the illumination radiation at grazing incidence (Gl), 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 on the one hand to optimize its reflectivity for the useful radiation and on the other hand to suppress stray light.

[0044] 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.

[0045] The illumination optics 16 include a deflecting mirror 17. The deflecting mirror 17 can be a planar deflecting mirror or, alternatively, a mirror with an effect that influences the beam 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.

[0046] The deflecting mirror 17 deflects the radiation from the illumination radiation source 13 onto a first facet mirror 18. If the first facet 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 facet mirror.

[0047] 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 102008 009 600 A1.

[0048] 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.

[0049] 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 use a microelectromechanical system in the second faceted mirror 19 with a plurality of facets individually angled by two perpendicular directions. to provide mutually converging axes of pivotable micromirrors 19', each preferably comprising an orientation sensor.

[0050] 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.

[0051] 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 particular, in illumination according to Köhler's principle.

[0052] The facets of the first faceted mirror 18 are each imaged superimposed on 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.

[0053] 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 is possible to It may 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 arranged tilted relative to a pupil plane of the projection system 20, as described, for example, in DE 102017 220 586 A1.

[0054] 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.

[0055] 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 (Gl 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 taken into account.

[0056] Alternatively, it is possible to dispense with the deflecting mirror 17 shown in Figure 1, in which case the facet mirrors 18, 19 must be arranged appropriately opposite the radiation source 13 and the collector 14.

[0057] 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.

[0058] The projection system 20 comprises a plurality of mirrors Mi, which are numbered according to their arrangement in the beam path of the projection exposure system 1. The mirrors Mi are optical elements 25.

[0059] In the example shown in Figure 1, the projection system 20 comprises six mirrors Mx to M6 as optical elements 25. Alternatives with four, eight, ten, twelve, or any other number of mirrors Mi are also possible. The penultimate mirror M5 and the last mirror M6 each have an aperture for the illumination radiation, making the projection system 20 a doubly obscured optical system. 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.

[0060] The reflective surfaces of the mirrors Mi can be designed as free-form surfaces without an axis of rotational symmetry. Alternatively, the reflective surfaces of the mirrors Mi can also be designed as aspherical surfaces with exactly one axis of rotational symmetry of the reflective surface shape. The mirrors Mi, just like the mirrors of the illumination optics 16, 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.

[0061] Projection system 20 has a large object-image offset in the y-direction between a y-coordinate of a Center of object field 11 and a y-coordinate of the center of 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.

[0062] The projection system 20 can in particular be anamorphic, i.e. it has in particular different image scales β x , ß y in the x and y directions. The two image scales ß x , ß y of the projection system 20 are preferably located at (ß x , ß y ) = (+ / - 0.25, / +- 0.125). A magnification factor β of 0.25 corresponds to a reduction in the ratio of 4:1, while a magnification factor β of 0.125 results in a reduction in the ratio of 8:1. A positive sign for the magnification factor β indicates a transformation without image inversion, a negative sign indicates a transformation with image inversion.

[0063] Other magnification ratios are also possible. Magnification ratios with the same sign and those with the same absolute value are also possible. x , ß y In the x and y directions, adjustments are possible.

[0064] 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 A.

[0065] The projection system 20 can, in particular, have a homocentric entrance pupil. This can be accessible. However, it can also be inaccessible.

[0066] Illuminated by lighting system 10 and by the The projection system 20 is transferred to the image plane 21. A reticle 30 (also called a mask) is arranged in object field 11. The reticle 30 is held by a reticle holder 31. The reticle holder 31 can be moved, particularly in a scanning direction, via a reticle displacement drive 32. In the illustrated embodiment, the scanning direction is in the y-direction.

[0067] The reticulum 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 reticulum 30 can be essentially 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 reticulum 30 can be 5 to 7 inches (12.70 to 17.78 cm) long and It should be 10 to 14 inches (25.40 to 35.56 cm) wide, and preferably 6 inches (15.24 cm) long and 12 inches (30.48 cm) wide.

[0068] 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 the wafer 35 via the wafer transfer drive 37 can be synchronized.

[0069] 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.

[0070] Figure 2 schematically shows such an electro-mechanical system 200 with elements 100 according to the invention, with Figure 2a showing the prior art, while Figure 2b shows the embodiment according to the invention.

[0071] The elements 100 according to the invention comprise the complete MEMS structure 101 of the micro-electro-mechanical system 200, including 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.

[0072] 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 gas 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.

[0073] As can be seen in Figure 2a, some 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 transmit the substances on the The basic structure of 110 arranged electrical elements may be disturbed, in particular short-circuited.

[0074] In order to reduce or completely avoid the problems caused by the parasitic coating 145, the element 100 shown in Figure 2a is shown in Figure 2b in a further developed embodiment according to the invention.

[0075] 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 basic structure 110 of the MEMS structure 101 can be at least significantly reduced, and in certain partial areas even substantially avoided.

[0076] 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.

[0077] As shown on the left side of Figure 2b, the parasitic coating 145 that occurs on the base structure 110 during the coating process is significantly reduced compared to the prior art according to Figure 2a.

[0078] 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 the coating process is deposited exclusively on this otherwise non-functional special feature 160. A corresponding illustration is shown on the right side of Figure 2b.

[0079] Figure 3 shows a further embodiment of the invention, which largely corresponds to that shown in Figure 2. Therefore, reference is made to the preceding explanations, and only the differences between the two embodiments will be discussed below.

[0080] In the embodiment shown in Figure 3, the projections 161 are no longer arranged directly on the sides of the mirror plates 130 (see Figure 2b), but rather form part of a special shape 160, by means of which the projections 161 lie in the plane (dashed line) formed by the pivot points 120' of the individual hinge arrangements 120, about which the respective mirror plate 130 can be pivoted. Because the projections 161 lie in this plane, their outer edges remain on a constant radius around the pivot point 120' (indicated by dash-dot lines), regardless of the pivoting of the mirror plates 130. Consequently, the distance between the projections 161 of adjacent mirror plates 130 can be chosen to be so small that practically no material can pass between them during coating.

[0081] To ensure that the swivel range of the mirror plates 130 is not restricted by the otherwise non-functional special shape 160, a recess 111 can be provided in the basic structure 110 (shown on the right in Figure 3), into which the special shapes 160 on the mirror elements 130 can be inserted when required.

[0082] Special shapes 160, as shown by way of example in Figure 3, can easily be produced together with the rest of the MEMS structure 101 using known manufacturing processes.

[0083] Figure 4 shows various ways to protect element 100 away from the mirror plate 130 from the negative effects of parasitic coatings. Element 100 comprises a MEMS structure 101, which in subsequent post-processing is itself further developed into a complete micro-electro-mechanical system or used as a component in a micro-electro-mechanical system.

[0084] The MEMS structure 101 also includes the basic 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 basic 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.

[0085] 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 inducing an interference between them. In connection with the elements 100 according to Figure 4, various measures according to the invention are shown to avoid such a continuous parasitic coating 145.

[0086] In the embodiment according to Figure 4a, projections 161, comparable to those on the mirror plate 130 according to Figures 2b or 3, are provided on each of the electrodes 150 as a shading and otherwise non-functional special feature 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.

[0087] Figure 4b also shows corresponding projections 161. However, these projections 161 have a different shape than those in Figure 4a. 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 from the coating 140.

[0088] In the embodiment shown in Figure 4c, the principle of shading the base structure 110 is also used to prevent a continuous parasitic coating 145 on it. However, instead of a projection 161 (see Figures 4a, 4b), a recess 162 in the MEMS structure 101, here in the electrodes 150 themselves, is used. A special, non-functional shape 160 is provided for shading. 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.

[0089] In the embodiment shown in Figure 4d, the electrodes 150 of the MEMS structure 101 do not have a special shape 160. Instead, a central projection 163 is provided on the base structure 110 as a special shape 160 that is otherwise non-functional. On both sides of the projection 163, steps 165 are formed in the MEMS structure 101. Since they are essentially parallel to the direction in which the material for the coating 140 is applied, the end faces 166 of these steps remain uncoated even after the end faces 155 of the electrodes 150 have been coated. 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.

[0090] The principle described in Figure 4d is also used in the embodiment shown in Figure 4e. However, instead of a projection 163 on the basic structure 110 (see Figure 4d), there is a central recess 164 as an otherwise non-functional special feature 160, which nevertheless also results in two steps 165 in the MEMS structure 101, the end faces 166 of which remain uncoated.

[0091] In order to ensure the latter even in the case of a deviation from an ideal direction for the application of the coating 140, a central recess 164 is provided in the embodiment according to Figure 4f as otherwise special non-functional design 160 formed steps 165 with an overhang 167.

[0092] The embodiments shown in Figures 4g and 4h are based on those shown in Figures 4d and 4e, but with the exception that several projections 163 or recesses 164 are provided, which—analogous to the embodiment described above—create a plurality of steps 165. The distance between the projections 163 or the width of the recesses 164 must 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—that is, 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 designed with overhangs, similar to the embodiment shown in Figure 4f.

Claims

31 AMENDED CLAIMS received at the International Bureau on 26 November 2025 (26.11.2025) 1. Element (100) for use in a micro-electro-mechanical system (200), wherein the element (100) is a MEMS- Structure (101) with a basic structure (110), at least 5 a micro-electro-mechanically movable mirror plate (130) of a micro-mirror relative to the basic structure (110) and at least one coating applied over a large area to partial surfaces (135) of the at least one mirror plate (130) provided for this purpose from one side of the element (100) 10 layering (140) comprises, characterized in that the at least one mirror plate (130) has at least one otherwise non-functional special shape (160) with which, for certain areas away from the area intended for this purpose, 15 partial surfaces (135) a parasitic coating (145) is avoided.

2. Element according to claim 1, characterized in that the special shape (160) provides a parasitic coating- 20 tung (145) of a specific sub-area of ​​the MEMS structure (101) is essentially completely avoided.

3. Element according to one of the preceding claims, characterized in that at least one special form (160) is a projection 25 (161) on a mirror plate (130) to generate an absorption- The creation is designed for a behind it, so that when a large area of ​​one side is coated, MEMS structure (101) the shaded area remains uncoated. AMENDED SHEET (ARTICLE 19) 32 4. Element according to one of the preceding claims, characterized in that the element (100) comprises at least two mirror plates (130), wherein at least two are arranged adjacent to each other. 5 net mirror plates (130) each have projections (161) on the sides facing each other.

5. Element according to claim 3 or 4, characterized in that at least one projection in a plane is formed by the rotation- 10 points of the mirror plate, around which the mirror plate can be pivoted, are arranged.

6. Element according to one of the preceding claims, characterized in that the element (100) is located away from the mirror plate (130) 15. tens another, otherwise non-functional shading element special shape (160) to at least reduce the negative effects of parasitic coatings.

7. Element according to claim 6, characterized in that 20 which at least one shading special form (160) off- side of the mirror plate (130) as a projection (161) on the MEMS structure (101) is formed.

8. Element according to claim 6 or 7, characterized in that 25 at least one shading special form (160) away from the mirror plate (130) by means of a recess (162) in the MEMS structure (101) is formed.

9. Element according to one of claims 6 to 8, characterized in that 30 at least one special form (160) apart from the mirror- AMENDED SHEET (ARTICLE 19) 33 plate (130) includes a step (165) in the MEMS structure (101) with such an abrupt transition that the end face (166) of stage (165) is coating-free.

10. Element according to claim 9, 5 characterized in that the at least one step (165) is parallel to the direction in which the material of the coating (140) in the area of ​​the The step (165) is applied, aligned, or with a Overhang (167) is formed. 10 11. Element according to one of claims 9 to 10, characterized in that two steps (165) are arranged on both sides of a central pre- Sprungs (163) are formed in the MEMS structure (101).

12. Element according to one of claims 9 to 11, 15 characterized in that two steps (165) are located on both sides of a central back- Sprungs (164) are formed in the MEMS structure (101).

13. Element according to one of the preceding claims, characterized in that 20 the element (100) an array of on a common The basic structure (110) consists of micro-electro-mechanically movable micromirrors.

14. Micro-electro-mechanical system (200) comprising at least one element (100) according to one of the preceding claims- 25 marriages. AMENDED SHEET (ARTICLE 19)

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