MEMS mirror array module

Abstract

The invention relates to a MEMS mirror array module (100) for use in projection exposure systems (1) for photolithography. The MEMS mirror array module (100) according to the invention comprises a MEMS mirror array structure (110) arranged on a rewiring substrate (120) and an interface element (140) arranged on the side of the rewiring substrate (120) facing away from the MEMS mirror array structure (110) for attaching the MEMS mirror array module (100) to a higher-level assembly. A cavity (150) is provided between the rewiring substrate (120) and the interface element (140), the wall (151) of which is thermally connected at least to the rewiring substrate (120) and a fluid line (200) for guiding heat transfer fluid along the wall (151) is in thermally conductive contact, which is guided with at least one end through the interface element (140) from the MEMS mirror array module (100).

Description

[0001] The invention relates to a MEMS mirror array module for use in projection exposure systems for photolithography.

[0002] 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.

[0003] In illumination systems, particularly projection illuminators designed for EUV applications (i.e., with exposure wavelengths from 5 nm to 30 nm), two faceted mirrors are typically positioned in the beam path between the actual exposure radiation source and the mask to be illuminated. These mirrors, operating on a principle similar to that of a honeycomb condenser, homogenize the radiation. The faceted mirror closer to the exposure radiation source is often a field faceted mirror, while the other is a pupil faceted mirror.

[0004] 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 electromechanically individually pivotable micromirrors. A corresponding method is disclosed, for example, in WO 2012 / 130768 A2.

[0005] 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 microelectromechanical systems (MEMS).

[0006] 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. 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.

[0007] 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.

[0008] In the previously mentioned application of photolithography, a MEMS mirror array is used in the illumination system. High-energy radiation strikes the mirror surfaces of the MEMS mirror array and is reflected in the desired direction; however, some of the incident radiation is also absorbed and thus transferred as heat into the MEMS structure.Together with the unavoidable heat input from the electronic components of the MEMS structure, and the fact that MEMS mirror arrays of illumination systems for photolithography, especially in the EUV range, are regularly arranged in a vacuum, so that heat dissipation by convection is excluded, increased temperatures can occur in the MEMS mirror arrays during the operation of such an illumination system, which can reduce the lifetime of both the reflective coating and the electronic and electromechanical components.

[0009] The object of the present invention is to create a MEMS mirror array module in which the disadvantages known from the prior art no longer occur or only occur to a reduced extent.

[0010] This problem is solved by a MEMS mirror array module according to claim 1. Advantageous further developments are the subject of the dependent claims.

[0011] Accordingly, the invention relates to a MEMS mirror array module comprising a MEMS mirror array structure arranged on a rewiring substrate and an interface element arranged on the side of the rewiring substrate facing away from the MEMS mirror array structure for attaching the MEMS mirror array module to a higher-level assembly, wherein a cavity is provided between the rewiring substrate and the interface element, the wall of which is thermally connected at least to the rewiring substrate and a fluid line for guiding heat transfer fluid along the wall is guided in thermally conductive contact, the fluid being led with at least one end through the interface element from the MEMS mirror array module.

[0012] First, some terms used in connection with the invention will be explained.

[0013] A substance or material is considered "thermally conductive" if it is fundamentally capable of transporting heat without simultaneously transporting mass, whereby the thermal conductivity is present at any temperature difference and at all temperatures that occur in expected operating conditions. A substance is considered thermally conductive at least if its thermal conductivity at 0 °C is greater than or equal to 0. 4Wm⋅K, preferably greater than or equal to 15Wm⋅K is and at least at all expected operating temperatures occurring in the material not below 1Wm⋅K sinks.

[0014] The invention is based on a known and not uncommon design of MEMS mirror array modules. This design comprises the actual MEMS mirror array structure with a plurality of mirror elements, each pivotable about at least one axis, typically about two mutually perpendicular axes. These mirror elements are provided with a reflective coating and can be individually pivoted by actuators that are also part of the MEMS mirror array structure. Sensors can also be provided to detect the respective angular position of the individual mirror elements. The MEMS mirror array structure can further include application-specific integrated circuits (ASICs), such as circuits for targeted pivoting of individual mirror elements. Additional sensors, such as temperature sensors, can also be designed and provided as application-specific integrated circuits.

[0015] The MEMS mirror array structure is mounted on and firmly bonded to a rewiring substrate. This substrate, often silicon-based, serves to bond—that is, to connect the electrical contacts—of the MEMS mirror array structure and to transfer these contacts into larger, typically more robust, contacts to which control and power cables can be plugged or soldered. Furthermore, the rewiring substrate ensures the structural integrity of the MEMS mirror array structure even under mechanical stress. Finally, the rewiring substrate also dissipates heat from the MEMS structure, which is why it is inherently thermally conductive.

[0016] An interface element is provided on the side of the rewiring substrate facing away from the MEMS mirror array structure. This interface element allows the MEMS mirror array module to be attached to a higher-level assembly, for example, to a mounting plate of a faceted mirror assembly for the illumination system of a projection exposure unit. The interface element can be designed as desired, particularly with regard to its intended use and the connection technology required. The material for the interface element is also generally arbitrary. However, at least in the prior art, a thermally conductive material is frequently used to enable heat conduction from the MEMS mirror array structure, via the rewiring substrate and the interface element, to the higher-level assembly.The interface element also regularly guides the supply and control lines for the MEMS mirror array structure into the higher-level assembly for suitable connection.

[0017] A cavity is provided between the rewiring substrate and the interface element, and it is essential that its wall is thermally connected to the rewiring substrate. In other words, in the event of a temperature difference, heat should flow from the rewiring substrate into the cavity wall, whereby the rewiring substrate itself can also form part of the cavity wall. The cavity can be used for various purposes, such as connecting control and supply lines for the MEMS mirror array structure. According to the invention, a fluid line is provided along the wall, serving to conduct a heat transfer fluid. A heat transfer fluid guided through the fluid line is in thermally conductive contact; that is, both the fluid line itself and the contact area between the fluid line and the wall are thermally conductive.Therefore, if there is a temperature difference between the part of the wall to which the fluid line is attached and the heat transfer fluid carried in it, heat is conducted from the wall into the heat transfer fluid.

[0018] The fluid line is guided through the interface element of the MEMS mirror array module at least at one end. The fluid line can protrude from the interface element or terminate on an outer surface of the interface element. Furthermore, the fluid line can be designed to allow the direct connection of additional fluid line sections. For this purpose, the fluid line can incorporate components of a fluid coupling on an outer surface of the interface element or be designed to facilitate the simple and leak-proof connection of another fluid line section, for example, by featuring a flange.

[0019] According to the invention, the design of a MEMS mirror array module allows heat introduced or generated at the MEMS mirror array structure to be transferred via the rewiring substrate, the thermally conductive wall of the cavity connected to it, and the thermally conductive fluid line in contact with it, into a heat transfer fluid located in the fluid line solely by thermal conduction. If the temperature of the heat transfer fluid in the fluid line in the area in contact with the wall is lower than that of the MEMS mirror array structure, a corresponding heat flow occurs, and heat is dissipated from the MEMS mirror array structure.

[0020] To ensure a permanent, thermally conductive contact between the fluid line and the wall, the fluid line can be bonded to the wall using a material bond. To further ensure good thermal conductivity between the wall and the fluid line, the material used for the bond is preferably also thermally conductive. The bond must be designed, or the material selected, in such a way that it does not fail at the joint due to stresses arising from differing coefficients of thermal expansion between the fluid line and the components forming the wall of the cavity. Of course, these stresses can also be reduced through design measures and by matching the coefficients of thermal expansion of the fluid line and the components forming the wall of the cavity.

[0021] The material used for the bond can be solder, which directly implies that the fluid line is attached to the wall by soldering. It is particularly preferred to use high-melting-point solder for brazing at temperatures above 450 °C. The use of a suitable solder ensures that the bond will not fail or soften at the temperatures typically expected at the joint during the desired heat conduction.

[0022] Alternatively, a thermally conductive adhesive can be used as the bonding material. To ensure this, the adhesive can, for example, contain silver particles and / or particles of hexagonal boron nitride.

[0023] It is also possible to achieve the desired material bond by sintering with a thermally conductive material. Silver sintering is particularly preferred, as it results in good thermal conductivity properties.

[0024] Particularly when the material bond is to be achieved by soldering or sintering, but the wall in the area where the fluid line rests is not directly suitable for this purpose, it is preferred if at least the part of the wall along which the fluid line runs is provided with a metallic coating. The metallic material for the coating can be selected, in particular, with regard to the solder or sintering material to be used. The coating must also be thermally conductive, which is generally the case with a metallic coating.

[0025] The wall along which the fluid line is routed can be parallel to the side of the rewiring substrate facing away from the MEMS mirror array structure and / or perpendicular to it.

[0026] If the fluid line is to run parallel to the rewiring substrate, it can be in direct contact with the substrate, provided the rewiring substrate forms part of the cavity wall. The heat conduction path from the MEMS mirror array structure to the fluid line, or to the heat transfer fluid within it, is then advantageously short.

[0027] A fluid line running along the wall perpendicular to the rewiring substrate can be advantageous for the fabrication of the MEMS mirror array module – especially if the wall in question is not part of the rewiring substrate: The fluid line can then be arranged, for example, through the opening of the cavity on the wall, which will later be covered by the rewiring substrate, and possibly bonded in a material-bonded manner before the cavity is then closed.

[0028] The cavity according to the invention can, in principle, already be formed by components known from the prior art, in particular the rewiring substrate and / or interface element. However, it has proven advantageous and preferred if the cavity and its wall are formed at least partially by a spacer element arranged between the rewiring substrate and the interface element. If the spacer element forms part of the cavity wall along which the fluid line is routed, the spacer element must be designed to be thermally conductive, at least in this area, to ensure the thermally conductive connection to the rewiring substrate according to the invention. The spacer element can be made of the same material as the rewiring substrate. Preferably, the spacer element is made of ceramic.

[0029] It is preferred that the fluid line is routed through the interface element from the MEMS mirror array module in a direction parallel to the surface normal of the MEMS structure. The fluid line then runs regularly from the MEMS mirror array module along the direction in which the module is inserted into a higher-level assembly, thus simplifying the connection to further fluid line sections.

[0030] The fluid line of the MEMS mirror array module can be a fluid line loop. Heat transfer fluid can then be supplied externally through this fluid line loop. For this purpose, the fluid line has an inlet and an outlet, each routed through the interface element, for connection to a heat transfer fluid circuit.

[0031] Alternatively, the fluid line can be a closed heat pipe, in which heat is transported from a warmer end—usually the end located in the cavity—to a cooler end solely due to processes occurring inside the heat pipe. If it is ensured that the temperature at the end of the heat pipe not located in the cavity is lower than in the cavity, heat can ultimately be dissipated from the MEMS mirror array structure. It is preferred that a capillary network be provided inside the heat pipe, thus designing the heat pipe as a heat pipe. Regardless, the fluid inside the heat pipe must be adapted to the expected temperatures when using the MEMS mirror array module, which, however, poses no problems for the specialist.

[0032] It is preferred that the MEMS mirror array module includes at least one application-specific integrated circuit for sensing the temperature in the circuit's region. With such a circuit, the temperature can be measured at a point within the MEMS mirror array module defined by the circuit's position. This information can simply be recorded for monitoring purposes. However, it is also possible to use the information from one or more suitably designed application-specific integrated circuits for active temperature control. Temperature control can be achieved, for example, by adjusting the temperature and / or flow rate of the heat transfer fluid through the fluid line, or by adjusting the temperature at the end of a fluid line designed as a heat pipe furthest from the cavity. A corresponding application-specific integrated circuit could, for example, be...The components can be integrated directly into the MEMS mirror array structure or arranged within the cavity of the MEMS mirror array module. The necessary design and the methods for manufacturing the corresponding circuits are familiar to the specialist.

[0033] The fluid line is preferably made of steel or copper. The final choice of material should be based on its corrosion resistance to the intended heat transfer fluid.

[0034] 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 MEMS mirror array modules according to the invention; Fig. 2: a schematic representation of a first embodiment of a MEMS mirror array module according to the invention; Fig. 3: a schematic representation of a second embodiment of a MEMS mirror array module according to the invention; and Fig. 4: a schematic representation of a third embodiment of a MEMS mirror array module according to the invention.

[0035] In Fig. Figure 1 shows a projection exposure system 1 for photolithography in a schematic meridional section. The projection exposure system 1 comprises a lighting system 10 and a projection system 20.

[0036] The illumination system 10 illuminates an object field 11 in an object plane or reticulum plane 12. The illumination system 10 comprises an illumination 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 illumination 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 illumination radiation source 13 can also be a free-electron laser (FEL).

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] In the Fig. In the example shown, projection system 20 comprises six mirrors M1 to M6. Alternatives with four, eight, ten, twelve or another number of mirrors M are possible. i are 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.

[0054] 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 i Like 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.

[0055] 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.

[0056] 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 , β y ) = (+ / - 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.

[0057] 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.

[0058] 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.

[0059] Projection system 20 can, in particular, have a homocentric entrance pupil. This may be accessible. However, it may also be inaccessible.

[0060] 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.

[0061] 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.

[0062] The in Fig. The projection exposure system 1 shown in Figure 1, or its illumination system 10, the above description of which essentially reflects known prior art, is characterized in that the first and / or second faceted mirror 18, 19 each contain several MEMS mirror array modules 100 according to the invention (see Figure 1). Fig. 2 to 4) is composed, wherein the MEMS mirror array modules 100 each comprise several micromirrors 18', 19'. The individual MEMS mirror array modules 100 are mounted on a higher-level assembly to jointly form the Fig. 1 to form the faceted mirrors 18, 19 shown in the sketch. In addition to the mechanical fastening, all necessary connections of the individual mirror array modules 100, e.g. to control electronics and / or cooling circuits, are also made via the higher-level assembly.

[0063] In Fig. Figure 2 schematically illustrates a first embodiment of a MEMS mirror array module 100 according to the invention. The illustration shows two sectional views, the section lines of which are marked in the other view. Hatching of the cut bodies has been omitted for clarity.

[0064] The MEMS mirror array module 100 initially comprises the actual MEMS mirror array structure 110, which includes the actual micromirrors 18', 19' as well as the mechanics and actuators required for their controllable tilting. Sensors for determining the angular position of the individual micromirrors 18', 19' may also be provided. The actual MEMS mirror array structure 110 is known from the prior art and is described, for example, in DE 10 2015 204 874 A1, DE 10 2015 220 018 A1 and DE 10 2008 009 600 A1. A detailed explanation of the MEMS mirror array structure 110 is therefore omitted here.

[0065] The MEMS mirror array structure 110 is mounted on a thermally conductive silicon rewiring substrate 120. The MEMS mirror array structure 110 is not only thermally conductive but also selectively electrically connected or bonded to the rewiring substrate 120 to convert the MEMS mirror array structure 110's intended electrical contacts into electrical contacts to which, for example, electrical control and supply lines 121 can be connected. The rewiring substrate 120 also provides the MEMS mirror array structure 110 with structural integrity that the MEMS mirror array structure 110 might not possess to a sufficient degree on its own.

[0066] A thermally conductive spacer element 130, also made of silicon or ceramic and therefore also thermally conductive, is connected to the rewiring substrate 120. On the side of the spacer element 130 facing away from the rewiring substrate 120, it is connected to an interface element 140.

[0067] The spacer element 130, together with the rewiring substrate 120, forms a cavity 150, the wall 151 of which is formed partly by the rewiring substrate 120 and partly by the spacer element 130. Since part of the wall is formed by the rewiring substrate 120 itself, and the remaining part by the spacer element 130, which is thermally connected to it, the entire wall 151 of the cavity can be considered to be thermally connected to the rewiring substrate 120.

[0068] The interface element 140 is designed to attach the MEMS mirror array module 100 to a higher-level assembly. In the illustrated embodiment, the interface element 140 is conically shaped so that it can be inserted into suitable openings in a carrier plate. It extends parallel to the surface normal of the MEMS mirror array structure 110, indicated by arrow 90. The electrical control and supply lines 121 are routed outwards through the cover surface 141 of the interface element 140, so that, after being threaded into the suitable opening in the carrier plate, the control and supply lines 121 generally do not obstruct the subsequent insertion of the MEMS mirror array module 100 into it.

[0069] The MEMS mirror array module 100 further comprises a fluid line 200. The fluid line 200 is designed as a fluid line loop, wherein the inlet 201 and outlet 202 of the fluid line loop are guided parallel to the surface normal 90 of the MEMS mirror array structure 110 through the interface element 140 from the MEMS mirror array module 100, so that they provide the advantages described in connection with the electrical control and supply lines 121 when inserting the MEMS mirror array module 100 into a designated opening in a higher-level assembly.

[0070] The fluid line 200 extends into the cavity 150 and is guided there in thermally conductive contact along the wall 151 of the cavity 150 – more precisely, the part of the wall 151 formed by the rewiring substrate 120 – in the form of a loop. The fluid line 200 is thus metallurgically bonded to the aforementioned part of the wall 151 by brazing. The material 152 used for this metallurgical bond is therefore brazing solder, which is thermally conductive.

[0071] In order to solder the fluid line 200 to the wall 151 or the silicon-based rewiring substrate 120, the relevant area of ​​the wall 151 is provided with a metallic coating 153. The material of the metallic coating 153, the material for the bonding 152 (i.e., the solder), and the material for the fluid line 200 are matched to ensure a reliable and strong connection across the entire temperature range expected during proper use of the MEMS mirror array module 100.

[0072] If the fluid line 200, or its inlet and outlet 201, 202, is suitably connected to a heat transfer fluid circuit, in particular a cooling circuit, a temperature difference arises between the MEMS mirror array structure 110, which may have an undesirably elevated temperature due to its own heat as well as absorbed radiation, and the heat transfer fluid in the area of ​​the fluid line 200, where it is guided along the wall 151 in thermally conductive contact, provided the temperature of the heat transfer fluid is appropriately controlled. Since the entire path between the MEMS mirror array structure 110 and the heat transfer fluid in the fluid line 200 is designed to be thermally conductive, heat can be dissipated from the MEMS mirror array structure 110, thereby lowering its temperature.Reversing the temperature difference would in principle also allow the MEMS mirror array structure 110 to be heated, but this plays practically no role in practice.

[0073] It is possible to actively control the temperature of the MEMS mirror array structure 110. For this purpose, the MEMS mirror array structure 110 can include one or more application-specific integrated circuits, each of which measures the temperature of the MEMS mirror array structure 110. The temperature measurement can then be transmitted via the electrical control and supply lines 121 to a higher-level controller, which then controls the flow rate and / or the temperature of the heat transfer fluid flowing through the fluid line 200.

[0074] In Fig. Figure 3 schematically illustrates a second embodiment of a MEMS mirror array module 100 according to the invention. Both in its illustration and structure, the MEMS mirror array module 100 is similar to the one shown in Figure 3. Fig. 3 the one from Fig. 2 largely. Reference is subsequently made to the preceding statements, and only the differences between the two exemplary embodiments will be discussed below.

[0075] In the embodiment according to Fig. 3 the loop-shaped fluid line 200 is guided along the part of the wall 151 of the cavity 150 in heat-conducting contact, in which the wall 151 runs perpendicular to the underside of the rewiring substrate 120.

[0076] Furthermore, the material-bonded connection between fluid line 200 and the part of the wall 151 is produced by silver sintering, whereby the material for the material bond 152 is sintered silver and thermally conductive.

[0077] Since the spacer element 130, which forms that part of the wall 151 of the cavity 150, is made of silicon or ceramic, for the intended material-bonded connection, the area of ​​the wall 151 along which the fluid line 200 is guided in thermally conductive contact is provided with a metallic and thus thermally conductive coating 153.

[0078] In Fig. Figure 4 schematically illustrates a third embodiment of a MEMS mirror array module 100 according to the invention. Both in its illustration and structure, the MEMS mirror array module 100 is similar to the one described in Figure 4. Fig. 4 the one from Fig. 2 largely. The following sections refer to the explanations regarding Fig. 2 referenced and the differences between the two exemplary embodiments are discussed below.

[0079] The fluid line 200 is according to Fig. 4 comparable to Fig. 2 along the underside of the rewiring substrate 120 as part of the wall 151 of the cavity 150. However, the fluid line 200 is not a fluid line loop, but rather a closed heat pipe, or—since it is provided with a capillary mesh inside—a heat pipe. One end of the fluid line 200 is located in the cavity 150, while the other end protrudes from the interface element 140. When the MEMS mirror array module 100 is installed, the end of the fluid line 200 protruding from the interface element 140 can be thermally connected to a heat sink in order to dissipate heat from the MEMS mirror array structure 110.

[0080] The fluid tube 200 is attached to the wall 151 of the cavity with adhesive as the material for the material-bonded connection 152. The adhesive is thermally conductive and contains silver particles, among other things for this purpose. A metallic coating 153 (see...) Fig. 2 and Fig. 3) can be omitted in this case. 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

[0004] DE 10 2015 204 874 A1 [0006, 0064] DE 10 2015 220 018 A1 [0007, 0064] DE 10 2008 009 600 A1 [0041, 0064] US 2006 / 0132747 A1

[0042] EP 1 614 008 B1

[0042] US 6,573,978

[0042] DE 10 2017 220 586 A1

[0047] US 2018 / 0074303 A1

[0058]

Claims

[1] MEMS mirror array module (100) comprising a MEMS mirror array structure (110) arranged on a rewiring substrate (120) and an interface element (140) arranged on the side of the rewiring substrate (120) facing away from the MEMS mirror array structure (110) for fastening the MEMS mirror array module (100) to a higher-level assembly, characterized by that a cavity (150) is provided between the rewiring substrate (120) and the interface element (140), the wall (151) of which is connected in a thermally conductive manner at least to the rewiring substrate (120) and a fluid line (200) for conducting heat transfer fluid is guided along the wall (151) in thermally conductive contact, which fluid line is guided with at least one end through the interface element (140) from the MEMS mirror array module (100). [2] MEMS mirror array module according to one of the preceding claims, characterized bythat the fluid line (200) is materially connected to the wall (151), wherein the material for the material connection (152) is heat-conducting. [3] MEMS mirror array module according to claim 2, characterized by that the material for the bond (152) is solder, preferably high-melting solder for brazing at temperatures above 450 °C. [4] MEMS mirror array module according to claim 2, characterized by that thermally conductive adhesive, preferably comprising silver particles and / or particles of hexagonal boron nitride, is used as the material for the material bond (152). [5] MEMS mirror array module according to claim 2, characterized by that the material bond is created by sintering, preferably silver sintering. [6] MEMS mirror array module according to one of the preceding claims, characterized by that at least the part of the wall (151) along which the fluid line (200) is guided is provided with a metallic coating (153). [7] MEMS mirror array module according to one of the preceding claims, characterized by that the wall (151) along which the fluid line (200) is guided is parallel to the side of the rewiring substrate (120) facing away from the MEMS mirror array structure (110) and / or perpendicular thereto. [8] MEMS mirror array module according to one of the preceding claims, characterized by that the cavity (150) and its wall (151) are formed at least partially by a spacer element (130) arranged between the rewiring substrate (120) and the interface element (140), wherein the spacer element (130) is preferably made of ceramic. [9] MEMS mirror array module according to one of the preceding claims, characterized by that the fluid line (200) is guided in a direction parallel to the surface normal (90) of the MEMS mirror array structure (110) through the interface element (140) from the MEMS mirror array module (100). [10] MEMS mirror array module according to one of the preceding claims, characterized by that the fluid line (200) is a fluid line loop with an inlet (201) and outlet (202) guided through the interface element (140) for connection to a heat fluid circuit. [11] MEMS mirror array module according to one of the preceding claims, characterized by that the fluid line (200) is a closed heat pipe, which preferably has a capillary network inside. [12] MEMS mirror array module according to one of the preceding claims, characterized by that the MEMS mirror array structure (110) comprises one or more application-specific integrated circuits and / or one or more application-specific integrated circuits are provided in the cavity (150), wherein at least one application-specific integrated circuit is designed to detect the temperature in the region of the circuit. [13] MEMS mirror array module according to one of the preceding claims, characterized by that the fluid line (200) is made of steel or copper.

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