MEMS mirror array module

Abstract

The invention relates to a MEMS mirror array module (100) for use in apparatuses for semiconductor technology The MEMS mirror array module (100) comprises at least one MEMS micromirror unit (200) having a MEMS mirror array structure (210) having two or more micromirrors (211) and an elongated interface element (250), beyond which the MEMS mirror array structure (210) protrudes laterally, and also comprising a superordinate assembly (300) having at least one receptacle (350) for the interface element (250) of the MEMS micromirror unit (200), wherein the MEMS micromirror unit (200) is secured in a receptacle (350) of the superordinate assembly (300) in such a way that the MEMS mirror array structure (210) of the MEMS micromirror unit (200) bears against the superordinate assembly (300). A gas atmosphere having a thermal conductivity of more than 0.05 W / (m ∙ K) is introduced in a gap (400) existing between interface element (250) and receptacle (350), wherein the MEMS mirror array structure (210) is sealed vis-à-vis the superordinate assembly (300) in such a way that gas atmosphere introduced into the gap (400) does not reach the micromirrors (211).

Description

20.11.2025 / BRMEMS mirror array module

[0001] The present application claims the priority of the German patent applications 10 2024 211 227.5, filed on 22 November 2024. The content of that German patent application is incorporated by reference in the present application text.

[0002] The invention relates to a MEMS mirror array module for use in apparatuses for semiconductor technology.

[0003] In the prior art, apparatuses for semiconductor technology are understood to be apparatuses that are used for the production or testing of microstructured component parts or the components required for this purpose. One example of such an apparatus is a photolithographic projection exposure apparatus .

[0004] Photolithography is used for producing microstructured component parts, such as for example integrated circuits. The projection exposure apparatus used in the process comprises an illumination system and a projection system. The image of a mask (also referred to as a reticle) illuminated by the illumination system is projected so as to reduce the size of the former onto a substrate, for example a silicon wafer, which is coated with a light-sensitive layer and arranged in the image plane of the projection system, using the projection system in order to transfer the mask structure to the light-sensitive coating of the substrate.

[0005] As a rule, two facet mirrors are arranged in the beam path between the actual exposure radiation source and the mask to be illuminated in the case of illumination systems, in particular of projection exposure apparatuses designed for the EUV range, i.e. for exposure wavelengths from 5 nm to 30 nm, and said mirrors allow homogenization of the radiation in amanner essential ly comparable to the principle of a fly' s eye condenser . The closer facet mirror in the beam path of the exposure radiation source is often a so-called field facet mirror, and the other facet mirror is a so-called pupil facet mirror .

[0006] In order to be able to produce di f ferent intensity and / or angle of incidence distributions during the illumination of the mask, it is known for the facets of at least one of the two facet mirrors - in particular those of the field facet mirror - to be formed from one or more micromirrors that are electromechanically pivotable on an individual basis . The same is correspondingly disclosed e . g . in WO 2012 / 130768 A2 .

[0007] In order to be able to achieve a small si ze of the individual micromirrors , it is known practice to design groups of micromirrors in the form of what is known as a MEMS mirror array, i . e . a mirror array made of microelectromechanical systems (MEMS ) .

[0008] In a MEMS mirror array, a multiplicity of small mirror elements are each mounted so as to be individually movable vis-a-vis a j oint base . For each mirror element , at least one actuator is provided and enables the mirror element to be adj usted along a respectively predefined degree of freedom . The mirror elements are frequently pivotable about two axes extending perpendicular to each other and parallel to the base , in which case enough actuators are then also provided to enable the mirror element to pivot about precisely these axes independently of each other . For the individual mirror elements , sensors can also be provided and enable the position of the mirror element to be determined relative to the base , so that the alignment of the mirrors can be monitored . A particularly advantageous embodiment for the mirrors of a MEMS mirror array is described in DE 10 2015 204 874 Al .

[0009] A method for producing a micromirror or a MEMS mirror array comprising a plurality of such micromirrors is disclosed - together with further details relating to a possible configuration of the micromirror - in DE 10 2015 220 018 Al .

[0010] In the case of the intended use in photolithography as already mentioned at the outset , a MEMS mirror array is used in the region of the illumination system . In this case , high- energy radiation is incident on the mirror surfaces of the MEMS mirror array and reflected from there in the respective desired direction; however, some of the incident radiation is also absorbed and hence introduced into the MEMS structure as heat . Together with the unavoidable heat input of the electronic components of the MEMS structure and the fact that MEMS mirror arrays of photolithographic illumination systems - especially in the EUV range - are regularly arranged in vacuo such that heat dissipation by convection is ruled out , it is possible as a matter of principle that elevated temperatures may arise in the MEMS mirror arrays during operation of such an illumination system and may reduce the service li fe of both the reflective coating and the electronic and electromechanical components .

[0011] The problem addressed by the present invention is that of developing a MEMS mirror array module in which the disadvantages known from the prior art no longer occur or occur only to a reduced extent .

[0012] This problem is solved by a MEMS mirror array module according to Claim 1 . The dependent claims relate to advantageous developments .

[0013] Accordingly, the invention relates to a MEMS mirror array module comprising at least one MEMS micromirror unit having a MEMS mirror array structure having two or more micromir-rors and an elongated interface element , beyond which the MEMS mirror array structure protrudes laterally, and also comprising a superordinate assembly having at least one receptacle for the interface element of the MEMS micromirror unit , wherein the MEMS micromirror unit is secured in a receptacle of the superordinate assembly in such a way that the MEMS mirror array structure of the MEMS micromirror unit bears against the superordinate assembly, and wherein a gas atmosphere having a thermal conductivity of more than 0.05 W / (m ■ K) is introduced in a gap existing between interface element and receptacle , wherein the MEMS mirror array structure is sealed vis-a- vis the superordinate assembly in such a way that gas atmosphere introduced into the gap does not reach the micromirrors .

[0014] The MEMS micromirror unit of the MEMS mirror array module according to the invention has an elongated interface element , beyond which the MEMS mirror array structure protrudes laterally . The superordinate assembly likewise belonging to the MEMS mirror array module according to the invention comprises at least one receptacle for precisely this interface element of the MEMS micromirror unit . In principle , the temperature of the MEMS mirror array structure is regulated by heat conduction from the MEMS mirror array structure into the superordinate as sembly, which can lead directly via the bearing surface of the MEMS mirror array structure on the superordinate assembly and via the interface element . In this case , the interface element can guide heat from the MEMS mirror array structure into a region of the receptacle of the superordinate assembly beyond the direct bearing of the MEMS mirror array structure on the superordinate assembly .

[0015] In order to be able to compensate for manufacturing tolerances and allow a certain amount of tolerance for positioning and aligning the MEMS micromirror unit vis-a-vis thesuperordinate as sembly during installation, the receptacle in the superordinate assembly is regularly configured with oversi ze vis-a-vis the interface element of the MEMS micromirror unit . In other words , the MEMS micromirror unit has some play following the insertion of the interface element into a receptacle of the superordinate assembly, and this play results in a gap between the interface element and the receptacle .

[0016] The invention has recogni zed that the gap in question, i f it is filled with air, acts practically like an insulator for the heat conduction, i . e . only very little heat is transferred via the gap even i f there is a temperature di f ference between the interface element and the receptacle . In order to enable ef ficient temperature regulation of the MEMS mirror array structure structurally connected to the interface element , the invention proposes improving the heat conduction via precisely this gap . In order to achieve this , the invention proposes filling the gap with a gas atmosphere , the thermal conductivity of which is at least 0.05 / (m ■ K) and is thus significantly higher than the thermal conductivity e . g . of air . It is particularly preferred i f the thermal conductivity of the gas atmosphere is at least 0.1as a result of which the heat conduction between the interface element and the receptacle in the superordinate assembly via the gap existing therebetween can be improved even further by comparison with air .

[0017] Especially in the cases in which the micromirrors of the MEMS mirror array structure are arranged in a vacuum, e . g . illumination systems for photolithography especially in the EUV range , suitable sealing between MEMS mirror array structure and superordinate assembly makes it possible to ensure that the gas atmosphere introduced into the gap does not reach the region in which the micromirrors are arranged . Consequently, the sealing is thus intended to be such that themicromirrors are unencumbered by the gas atmosphere introduced into the gap and remain in vacuo, for example.

[0018] The term "gas atmosphere" here denotes an atmosphere which differs from air and which is composed of a gas or a gas mixture and the composition of which is frequently known, but at least the thermal conductivity of which is determinable. In general, the gas atmosphere is generated artificially, such that its composition and moreover also the thermal conductivity can be monitored.

[0019] It is preferred if the gas atmosphere is a helium gas atmosphere or a hydrogen gas atmosphere. The corresponding gas atmospheres are distinguished by the fact that they predominantly to the extent of at least 50%, preferably at least 75%, more preferably at least 75%, consist of the gas respectively mentioned, i.e. either helium or hydrogen. Consequently, the thermal conductivity of the gas atmosphere is crucially influenced by helium or hydrogen, respectively, which according to the VDI Heat Atlas (12th edition) have a thermal conductivity of 0.1536 W / (m ■ K) for helium and 0.1807 W / (m ■ K) for hydrogen at 25°C. If a gas atmosphere almost exclusively consists of a single gas, the thermal conductivity of the gas atmosphere substantially corresponds to the thermal conductivity of the corresponding gas.

[0020] Especially if the gas atmosphere provided is problematic beyond the existing gap, e.g. because, like a helium gas atmosphere, it may attack electronic components or, like a hydrogen gas atmosphere, it is explosive, it is preferred for the gas atmosphere in the region of the MEMS mirror array module to be restricted to the existing gap and a different atmosphere to be present in internal cavities of the MEMS mirror array module. A corresponding restriction can be achieved by suitable sealing of the gap. In the case of a helium gas atmo-sphere, this ensures e.g. that electronic components situated inside the MEMS mirror array module do not come into contact with the helium gas atmosphere. In the case of a hydrogen gas atmosphere, the volume thereof can be kept small and moreover limited to a region in which active electrical components that might cause hydrogen ignition are not usually arranged.

[0021] It has been found that sufficient temperature regulation of the MEMS micromirror unit can already be achieved if gas atmosphere in the existing gap is stationary. However, it is also possible to actively flush the existing gap with the gas of the gas atmosphere, i.e. in other words to supply gas in such a way that a flow is established in the existing gap. In this case, the temperature of the gas is preferably regulated prior to flushing. Flushing with gas, in particular temperature-regulated gas, enables the temperature regulation of the MEMS micromirror unit to be further improved.

[0022] If the MEMS mirror array module comprises a plurality of MEMS micromirrors units, it is preferred if at least two of the receptacles provided therefor in the superordinate assembly are fluidically interconnected in such a way that the gaps existing between these receptacles and the interface elements respectively inserted therein are fluidically connected. On account of this fluidic connection, it is possible to introduce the gas atmosphere jointly into the fluidically connected gaps .

[0023] In this case, it is preferred if an inlet fluidically connected to at least one of the at least two fluidically interconnected receptacles is provided on the superordinate assembly. Via this inlet, the gas atmosphere can be initially introduced and supplemented, if appropriate, if losses occur, e.g. in the region of seals.

[0024] It is also possible for an outlet fluidically connected to at least one of the at least two fluidically interconnected receptacles to be provided on the superordinate assembly, wherein inlet and outlet are preferably fluidically connected to different receptacles. If both inlet and outlet are provided, the fluidically connected receptacles can be actively flushed as necessary.

[0025] If inlet and / or outlet are / is provided, the gas atmosphere in the fluidically connected gaps can be actively regulated. For this purpose, the inlet and / or the outlet can be configured to be controllable e.g. with the aid of regulatable valves, in order to regulate inflow and / or outflow of the gas atmosphere. Furthermore, suitable sensors, such as pressure sensors, flow sensors or temperature sensors, can be provided in order to regulate the gas atmosphere to corresponding desired target values. In this regard, it is possible e.g. to stipulate that a reduced pressure of 0.4 bar to 0.8 bar, preferably of 0.5 bar to 0.7 bar, more preferably of 0.6 bar, prevails in the gaps.

[0026] The invention will now be described by way of example on the basis of advantageous embodiments with reference to the accompanying drawings, in which:Figure 1: shows a schematic illustration of a photolithographic projection exposure apparatus comprising MEMS mirror array modules according to the invention;Figure 2: shows a schematic partial illustration of a first exemplary embodiment of a MEMS mirror array module according to the invention;Figure 3: shows a schematic partial illustration of a second exemplary embodiment of a MEMS mirror array module according to the invention;Figure 4: shows a schematic partial illustration of a third exemplary embodiment of a MEMS mirror array module according to the invention;Figure 5: shows a schematic partial illustration of a fourth exemplary embodiment of a MEMS mirror array module according to the invention.

[0027] Figure 1 illustrates a schematic meridional section through a photolithographic projection exposure apparatus 1 as an example of an apparatus for semiconductor technology. In this case, the projection exposure apparatus 1 comprises an illumination system 10 and a projection system 20.

[0028] An object field 11 in an object plane or reticle plane 12 is illuminated with the aid of the illumination system 10. For this purpose, the illumination system 10 comprises an exposure radiation source 13, which, in the illustrated exemplary embodiment, emits illumination radiation at least comprising used light in the EUV range, i.e. with a wavelength of between 5 nm and 30 nm in particular. The exposure radiation source 13 can be a plasma source, for example an LPP (laser produced plasma) source or a GDPP (gas discharge produced plasma) source. It can also be a synchrotron-based radiation source. The exposure radiation source 13 can also be a free electron laser (FEL) .

[0029] The illumination radiation emerging from the exposure radiation source 13 is initially focused in a collector 14. The collector 14 can be a collector with one or with a plurality of ellipsoidal and / or hyperboloidal reflection surfaces.The illumination radiation can be incident on the at least one reflection surface of the collector 14 with grazing incidence ( GI ) , i . e . at angles of incidence of greater than 45 ° , or with normal incidence (NI ) , i . e . at angles of incidence of less than 45 ° . The collector 14 can be structured and / or coated on the one hand for optimi zing its reflectivity for the used radiation and on the other hand for suppressing extraneous light .

[0030] Downstream of the collector 14 , the illumination radiation propagates through an intermediate focus in an intermediate focal plane 15 . I f the illumination system 10 is constructed in a modular design, the intermediate focal plane 15 can be used, in principle , for the separation - including the 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 optical unit 16 described below . In the case of a corresponding separation, radiation source module and illumination optical unit 16 then j ointly form a modularly constructed illumination system 10 .

[0031] The illumination optical unit 16 comprises a deflection mirror 17 . The deflection mirror 17 can be a plane deflection mirror or, alternatively, a mirror with a beam-influencing effect that goes beyond the pure deflection ef fect . Alternatively or additionally, the deflection mirror 17 can be embodied as a spectral filter separating a used light wavelength of the illumination radiation from extraneous light having a wavelength that deviates therefrom .

[0032] The deflection mirror 17 is used to deflect the radiation emanating from the exposure radiation source 13 to a first facet mirror 18 . I f - as in the present case - the first facet mirror 18 is arranged in a plane of the illumination op-tical unit 16 which is optically conj ugate to the reticle plane 12 as a field plane , this facet mirror is also referred to as a field facet mirror .

[0033] The first facet mirror 18 comprises a multiplicity of micromirrors 18 ' that are individually pivotable about two mutually perpendicular axes in each case , for the purpose of controllably forming facets which are each configured with an orientation sensor (not depicted here ) for determining the orientation of the micromirror 18 ' . The first facet mirror 18 is thus a microelectromechanical system (MEMS system) , as also described in DE 10 2008 009 600 Al , for example .

[0034] A second facet mirror 19 is arranged downstream of the first facet mirror 18 in the beam path of the illumination optical unit 16 , with the result that this yields a doubly faceted system, the fundamental principle of which is also referred to as a fly ' s eye integrator . I f the second facet mirror 19 - as in the illustrated exemplary embodiment - is arranged in a pupil plane of the illumination optical unit 16 , it is also referred to as a pupil facet mirror . However, the second facet mirror 19 can also be arranged at a distance from a pupil plane of the illumination optical unit 16 , as a result of which a specular reflector arises from the combination of the first and the second facet mirror 18 , 19 , for example as described in US 2006 / 0132747 Al , EP 1 614 008 Bl and US 6 , 573 , 978 .

[0035] The second facet mirror 19 need not in principle be constructed from pivotable micromirrors , but rather can comprise individual facets formed from one mirror or a manageable number of mirrors which are signi ficantly larger than micromirrors , which facets are either stationary or tiltable only between two defined end positions . It is however - as illustrated - also possible , in the second facet mirror 19 , toprovide a microelectromechanical system having a multiplicity of micromirrors 19 ' that are individually pivotable about two mutually perpendicular axes in each case , each preferably comprising an orientation sensor .

[0036] The individual facets of the first facet mirror 18 are imaged into the obj ect field 11 with the aid of the second facet mirror 19 , with this regularly only being approximate imaging . The second facet mirror 19 can be the last beam-shaping mirror or else actually the last mirror for the illumination radiation in the beam path upstream of the obj ect field 11 .

[0037] In each case one of the facets of the second facet mirror 19 is assigned to exactly one of the facets of the first facet mirror 18 for the purpose of forming an illumination channel for illuminating the obj ect field 11 . This can in particular result in illumination according to the Kohler principle .

[0038] The facets of the first facet mirror 18 are imaged overlaid on one another by way of a respective assigned facet of the second facet mirror 19 , for the purpose of illuminating the obj ect field 11 . Here , the illumination of the obj ect field 11 is as homogeneous as possible . It preferably has a uni formity error of less than 2 % . Field uni formity can be achieved by overlaying di f ferent illumination channels .

[0039] By selecting the ultimately used illumination channels , which is possible without problems by way of a suitable setting of the micromirrors 18 ' of the first facet mirror 18 , it is still possible to set the intensity distribution in the entrance pupil of the proj ection system 20 described below . This intensity distribution is also referred to as illumination setting . Incidentally, it may be advantageous here to arrange the second facet mirror 19 not exactly in a plane that is op-tically conjugate to a pupil plane of the projection system20. In particular, the pupil facet mirror 19 can be arranged so as to be tilted relative to a pupil plane of the projection system 20, as is described in DE 10 2017 220 586 Al, for examp 1 e .

[0040] In the arrangement of the components of the illumination optical unit 16 as illustrated in Figure 1, however, the second facet mirror 19 is arranged in an area conjugate to the entrance pupil of the projection system 20. Deflection mirror 17 and the two facet mirrors 18, 19 are arranged tilted both vis-a-vis the object plane 12 and vis-a-vis one another in each case.

[0041] In an alternative embodiment (not illustrated) of the illumination optical unit 16, a transfer optical unit comprising one or more mirrors can additionally be provided in the beam path between the second facet mirror 19 and the object field 11. The transfer optical unit can in particular comprise one or two normal-incidence mirrors (NI mirrors) and / or one or two grazing-incidence mirrors (GI mirrors) . Using an additional transfer optical unit, it is possible in particular to take account of different poses of the entrance pupil for the tangential and for the sagittal beam path of the projection system 20 described below.

[0042] It is alternatively possible for the deflection mirror 17 illustrated in Figure 1 to be dispensed with, for which purpose the facet mirrors 18, 19 should then be suitably arranged vis-a-vis the radiation source 13 and the collector 14.

[0043] The object field 11 in the reticle plane 12 is transferred to the image field 21 in the image plane 22 with the aid of the projection system 20.

[0044] For this purpose, the projection system 20 comprises a plurality of mirrors M±, which are consecutively numbered in accordance with their arrangement in the beam path of the projection exposure apparatus 1. The mirrors M±are optical elements 25.

[0045] In the example illustrated in Figure 1, the projection system 20 comprises six mirrorsto M6as optical elements 25. Alternatives with four, eight, ten, twelve or any other number of mirrors M±are likewise possible. The penultimate mirror M5and the last mirror M6each have a passage opening for the illumination radiation, as a result of which the illustrated projection system 20 is a doubly obscured optical unit. The projection system 20 has an image-side numerical aperture that is greater than 0.3 and can also be greater than 0.6, and can be for example 0.7 or 0.75.

[0046] The reflection surfaces of the mirrors M±can be in the form of freeform surfaces without an axis of rotational symmetry. However, the reflection surfaces of the mirrors M±can alternatively also be designed as aspherical surfaces with exactly one axis of rotational symmetry of the reflection surface shape. Just like the mirrors of the illumination optical unit 16, the mirrors M±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.

[0047] The projection system 20 has a large object-image offset in the y-direction between a y-coordinate of a centre of the object field 11 and a y-coordinate of the centre of the image field 21. This object-image offset in the y-direction can be of approximately the same magnitude as a z-distance between the object plane 12 and the image plane 22.

[0048] In particular, the projection system 20 can be designed to be anamorphic, that is to say it has different imaging scales px, pyin the x- and y-directions in particular. The two imaging scales px, pyof the projection system 20 are preferably (px, py) = ( + / -0.25, / + -0.125) . An imaging scale p of 0.25 corresponds here to a reduction with a ratio 4:1, while an imaging scale p of 0.125 results in a reduction with a ratio of 8:1. A positive sign in the case of the imaging scale p means imaging without image inversion; a negative sign means imaging with image inversion.

[0049] Other imaging scales are likewise possible. Imaging scales px, pywith the same sign and the same absolute magnitude in the x- and y-directions are also possible.

[0050] The number of intermediate image planes in the x-direc- tion and in the y-direction in the beam path between the object field 11 and the image field 21 can be the same or different, depending on the embodiment of the projection system20. Examples of projection systems 20 with different numbers of such intermediate images in the x-direction and y-direction are known from US 2018 / 0074303 Al.

[0051] In particular, the projection system 20 can comprise a homocentric entrance pupil. The latter can be accessible. However, it can also be inaccessible.

[0052] A reticle 30 (also referred to as mask) arranged in the object field 11 is exposed by the illumination system 10 and transferred by the projection system 20 onto the image plane21. The reticle 30 is held by a reticle holder 31. The reticle holder 31 is displaceable by way of a reticle displacement drive 32 in particular in a scanning direction. In the exemplary embodiment illustrated, the scanning direction runs in the y-direction.

[0053] The reticle 30 can have an aspect ratio of between 1:1 and 1:3, preferably between 1:1 and 1:2, and particularly preferably of 1:1 or 1:2. The reticle 30 can be configured to be substantially rectangular and has preferably a length and a width of 5 to 7 inches (12.70 to 17.78 cm) , more preferably a length and a width of 6 inches (15.24 cm) . As an alternative thereto, the reticle 30 can have a length of 5 to 7 inches (12.70 cm to 17.78 cm) and a width of 10 to 14 inches (25.40 cm to 35.56 cm) , preferably a length of 6 inches (15.24 cm) and a width of 12 inches (30.48 cm) .

[0054] A structure on the reticle 30 is imaged onto a lightsensitive layer of a wafer 35 arranged in the region of the image field 21 in the image plane 22. The wafer 35 is held by a wafer holder 36. The wafer holder 36 is displaceable by way of a wafer displacement drive 37 in particular along the y- direction. The displacement, firstly, of the reticle 30 by way of the reticle displacement drive 32 and, secondly, of the wafer 35 by way of the wafer displacement drive 37 can be synchronized with one another.

[0055] The projection exposure apparatus 1 illustrated in Figure 1, or its illumination system 10, the above description of which reflects essentially known prior art, is distinguished by the fact that the first and / or second facet mirror 18, 19 is in each case composed of a plurality of MEMS mirror array modules 100 according to the invention (cf. Figures 2 to 4) , with the MEMS mirror array modules 100 each comprising a plurality of micromirrors 18', 19' . The individual MEMS mirror array modules 100 are secured to a superordinate assembly in order to jointly form the facet mirrors 18, 19 schematically depicted in Figure 1. In addition to mechanical securing, the superordinate assembly also provides any required link of the individual mirror array modules 100, for example to control electronics and / or cooling circuits.

[0056] Figures 2 to 4 schematically illustrate various exemplary embodiments of MEMS mirror array modules 100 according to the invention .

[0057] In this case , the MEMS mirror array modules 100 each comprise a plurality of MEMS micromirror units 200 , of which, however, only one MEMS micromirror unit 200 is illustrated in greater detail as a matter of principle . In this case , each MEMS micromirror unit 200 comprises a MEMS mirror array structure 210 compri sing the actual micromirrors 211 with the actuators (not illustrated) required for adj usting the micromirrors 211 and the electronics required for control purposes , the latter being arranged internally . The electrical connection of the MEMS micromirror unit 200 to a power supply and / or a superordinate controller is likewise not illustrated .

[0058] The MEMS micromirror units 200 each comprise an elongated interface element 250 , beyond which the MEMS mirror array structure 210 protrudes laterally . In the illustrated exemplary embodiments , the interface element 250 has a cylindrical configuration . However, other shapes for the interface element 250 are sel f-evidently also conceivable , for example a conical , pyramidal or polygonal shape .

[0059] The MEMS micromirror units 200 are each secured to a superordinate component 300 , with the actual means of securing not being illustrated . In this case , in principle , the MEMS micromirror units 200 bear against the superordinate assembly 300 , with a seal 220 being provided, while the interface elements 250 are inserted into receptacles 350 provided therefor, which likewise have a cylindrical configuration, on the superordinate assembly 300 . In order to enable alignment of the MEMS micromirror units 200 , the receptacle 350 on the superordinate assembly 300 is configured with oversi ze vis-a-vis the interface elements 250 , and so in principle this results in agap 400 between the interface element 250 and the receptacle 350 .

[0060] In the exemplary embodiment in accordance with Figure 2 , it is provided that the region which faces away from the MEMS mirror array structure 210 and which is not situated in the evacuated region of the proj ection exposure apparatus 1 and which also includes the gap 400 between interface element 250 and receptacle 350 , is completely exposed to a helium gas atmosphere 500 . The helium gas atmosphere 500 has a thermal conductivity o f approximately 0.1536 W / (m ■ K) at 25 ° C, as per the VDI Heat Atlas ( 12th edition) . There is thus good heat conduction between interface element 250 and receptacle 350 , which helps to dissipate heat from the MEMS mirror array structure 210 via the interface element 250 and the gap 400 into the receptacle 350 or the superordinate assembly 300 . In relation to an embodiment which is not according to the invention and in which the gap 400 is filled with air, the temperature regulation of the MEMS mirror array structure 210 can thus be significantly improved .

[0061] Since the embodiment variant in accordance with Figure 2 cannot exclude a situation in which electronic components might come into contact with the helium gas atmosphere and be damaged as a result , in the exemplary embodiment in accordance with Figure 3 the region in which the helium gas atmosphere is present is restricted to the actual gap 400 . For this purpose , a suitable seal 410 is provided at the end of the receptacle 350 facing away from the MEMS mirror array structure 210 , said seal limiting the helium gas atmosphere to the gap 400 .

[0062] In the exemplary embodiment in accordance with Figure 4 , provision i s made for flushing the gap 400 with the gas of the helium atmosphere 500 , i . e . with helium, which is indicated by the arrow 420 . For flushing purposes it is necessary,as known to a person skilled in the art , to provide suitable in- and outflows (not illustrated) . The region, the region flushed with hel ium, or the region of the helium atmosphere 500 , can in this case be restricted to the actual gap 400 , as shown in Figure 3 .

[0063] Figure 5 illustrates a further exemplary embodiment based on the exemplary embodiment in Figure 3 . In this exemplary embodiment , a plurality of MEMS micromirror units 200 are arranged in a plurality of receptacles 350 of the superordinate assembly 300 , wherein the receptacles 350 are fluidic- ally interconnected by suitable channels 360 in the structure of the superordinate assembly 300 . On account of the seals 410 and also the seal 220 of the MEMS mirror array structure 210 vis-a-vis the superordinate assembly 300 , this results in a common closed gas space for the gas atmosphere which extends over all the gaps 400 .

[0064] On the superordinate assembly 300 , an inlet 370 and an outlet 380 are furthermore provided, via which the gas for the gas atmosphere can be introduced or discharged or extracted by suction in a valve-controlled manner . Moreover, it is possible , via the inlet and the outlet , to flush the gas space extending over all the gaps 400 with the gas atmosphere , as has been explained in connection with Figure 4 .

[0065] The provi sion of the gas and any reduced pressure that may be required at the outlet are implemented in a superordinate manner and are not illustrated in Figure 5 . Figure 5 likewise does not i llustrate possible sensors , such as pressure sensors and / or f low sensors , which can be used to regulate the gas atmosphere , e . g . by suitable control of inlet and / or outlet .

Claims

Patent Claims1. MEMS mirror array module (100) comprising at least one MEMS micromirror unit (200) having a MEMS mirror array structure (210) having two or more micromirrors (211) and an elongated interface element (250) , beyond which the MEMS mirror array structure (210) protrudes laterally, and also comprising a superordinate assembly (300) having at least one receptacle (350) for the interface element (250) of the MEMS micromirror unit (200) , wherein the MEMS micromirror unit (200) is secured in a receptacle (350) of the superordinate assembly (300) in such a way that the MEMS mirror array structure (210) of the MEMS micromirror unit (200) bears against the superordinate assembly (300) , characterized in that a gas atmosphere having a thermal conductivity of more than 0.05is introduced in a gap (400) existing between interface element (250) and receptacle (350) , wherein the MEMS mirror array structure (210) is sealed vis-a-vis the superordinate assembly (300) in such a way that gas atmosphere introduced into the gap (400) does not reach the micromirrors (211) .

2. MEMS mirror array module according to Claim 1, characterized in that the gas atmosphere has a thermal conductivity of more than 0.1 W / (m ■ K) .

3. MEMS mirror array module according to either of the preceding claims, characterized in that the gas atmosphere is a helium gas atmosphere or a hydrogen gas atmosphere.

4. MEMS mirror array module according to any of the preceding claims , characterized in that the gas atmosphere in the region of the MEMS mirror array module (100) is restricted to the existing gap (400) and a different atmosphere is present in internal cavities of the MEMS mirror array module (100) .

5. MEMS mirror array module according to any of the preceding claims , characterized in that the gas atmosphere in the existing gap (400) is stationary.

6. MEMS mirror array module according to any of Claims 1 to 4, characterized in that the existing gap (400) is actively flushed with the gas of the gas atmosphere, wherein the temperature of the gas is preferably regulated prior to flushing.

7. MEMS mirror array module according to any of the preceding claims , characterized in that the MEMS mirror array module (100) comprises a plurality of MEMS micromirror units (200) and at least two of the receptacles (350) provided therefor in the superordinate assembly (300) are fluidically interconnected in such a way that the gaps (400) existing between these receptacles (350) and the interface elements (250) respectively inserted therein are fluidically connected.

8. MEMS mirror array module according to Claim 7, characterized in that an inlet (370) fluidically connected to at least one of the at least two fluidically interconnected receptacles (350) is provided on the superordinate assembly (300) .

9. MEMS mirror array module according to Claim 7 or 8, characterized in that an outlet (380) fluidically connected to at least one of the at least two fluidically interconnected receptacles (350) is provided on the superordinate assembly (300) , wherein inlet (370) and outlet (380) are preferably fluidically connected to different receptacles (350) .

10. MEMS mirror array module according to Claim 8 or 9, characterized in that the inlet (370) and / or the outlet (380) are / is configured to be controllable.

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