Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/70—Microphotolithographic exposure; Apparatus therefor
  • G03F7/708—Construction of apparatus, e.g. environment aspects, hygiene aspects or materials
  • G03F7/70808—Construction details, e.g. housing, load-lock, seals or windows for passing light in or out of apparatus
  • G03F7/70825—Mounting of individual elements, e.g. mounts, holders or supports
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/08—Mirrors
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/08—Mirrors
  • G02B5/0891—Ultraviolet [UV] mirrors
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/08—Mirrors
  • G02B5/09—Multifaceted or polygonal mirrors, e.g. polygonal scanning mirrors; Fresnel mirrors
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/12—Reflex reflectors
  • G02B5/126—Reflex reflectors including curved refracting surface
  • G02B5/132—Reflex reflectors including curved refracting surface with individual reflector mounting means
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
  • G02B7/18—Mountings, adjusting means, or light-tight connections, for optical elements for prisms; for mirrors
  • G02B7/181—Mountings, adjusting means, or light-tight connections, for optical elements for prisms; for mirrors with means for compensating for changes in temperature or for controlling the temperature; thermal stabilisation
  • G02B7/1815—Mountings, adjusting means, or light-tight connections, for optical elements for prisms; for mirrors with means for compensating for changes in temperature or for controlling the temperature; thermal stabilisation with cooling or heating systems
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
  • G02B7/18—Mountings, adjusting means, or light-tight connections, for optical elements for prisms; for mirrors
  • G02B7/182—Mountings, adjusting means, or light-tight connections, for optical elements for prisms; for mirrors for mirrors
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/70—Microphotolithographic exposure; Apparatus therefor
  • G03F7/70058—Mask illumination systems
  • G03F7/70075—Homogenization of illumination intensity in the mask plane by using an integrator, e.g. fly's eye lens, facet mirror or glass rod, by using a diffusing optical element or by beam deflection
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49826—Assembling or joining

Definitions

• the invention relates to a facet mirror device that may be used within an optical device used in exposure processes, in particular in microlithography systems. It further relates to an optical imaging arrangement comprising such a facet mirror device. It further relates to a method of supporting a facet element of a facet mirror device and a method of manufacturing a facet mirror device.
• the invention may be used in the context of photolithography processes for fabricating microelectronic devices, in particular semiconductor devices, or in the context of fabricating devices, such as masks or reticles, used during such
• the optical systems used in the context of fabricating microelectronic devices comprise a plurality of optical element modules comprising optical elements, such as lenses, mirrors, gratings etc., in the light path of the optical system.
• Those optical elements usually cooperate in an exposure process to illuminate a pattern formed on a mask, reticle or the like and to transfer an image of this pattern onto a substrate such as a wafer.
• the optical elements are usually combined in one or more functionally distinct optical element groups that may be held within distinct optical element units.
• Facet mirror devices as the ones mentioned above, among others may serve to homogenize the exposure light beam, i.e. to effect a power distribution within the exposure light beam which is as uniform as possible.
• a third approach to support the facet elements is disclosed in DE 102 05 425 A1 (Holderer et al.) wherein the spherical rear surface of the facet element, more or less in a three point contact, rests against three small spheres each located at a free end of a support pin element.
• the heat transfer is even worse while as well not considerably reducing the manufacturing effort necessary for the three small spheres to have the desired accuracy.
• a manipulating lever is connected to the rear surface of the facet element, corresponding manipulators acting on said manipulating Sever to adjust the position and, predominantly, the orientation of the facet element with respect to the support element. Furthermore, in some cases, the manipulating lever is used for fixing the facet element relative to the support element once it has bee adjusted,
• This solution has the disadvantage that the manipulating lever adds to the complexity and, ultimately, to the cost not only of the facet element but also of other components such as the support element. Furthermore, multiple manipulators are required generating mutually counteracting manipulation forces to allow accurate adjustment in a reasonable amount of time.
• such a high precision edge as one possible variant to support the facet element, allows easy implementation of a further aspect of the invention, namely the use of negative pressure acting on the facet element to generate a contact load between the support element and the facet element.
• This has the advantage that the contact load (eventually adjustable via a corresponding adjustment of the negative pressure) generates a resistance against manipulation forces reducing the effort, in particular the number and/or complexity of the manipulators, necessary to adjust the facet element.
• a facet mirror device comprising a facet element and a support element, the support element supporting the facet element.
• the facet element comprises a curved first support section while the support element comprises a second support section, the second support section forming a support edge contacting the first support section in a region of contact to support the facet element.
• an optical imaging arrangement comprising a mask unit adapted to receive a pattern, a substrate unit adapted to receive a substrate, an illumination unit adapted to illuminate the pattern, an optical projection unit adapted to transfer an image of the pattern onto the substrate.
• At least one of the illumination unit and the optical projection unit comprises a facet mirror device, the facet mirror device comprising a facet element and a support element, the support element supporting the facet element.
• the facet element comprises a curved first support section, while the support element comprises a second support section, the second support section forming a support edge contacting the first support section in a region of contact to support the facet element.
• a method of supporting a facet element of a facet mirror device comprising providing a facet element and a support element, and supporting the facet element at a curved first support section of the facet element via a second support section of the support element, the second support section forming a support edge contacting the first support section in a region of contact to support the facet element.
• a method of manufacturing a facet mirror device comprising, in a preparation step, providing a facet element and a support element, the facet element having a front surface optically used during operation of the facet mirror device and a rear surface comprising a curved first support section, and the support element having a second support section forming a support edge,
• the facet element is placed onto the support element such that the a curved support edge contacts the first support section in a region of contact to support the facet element.
• a method of manufacturing a facet mirror device comprising, in a preparation step, providing a facet element and a support element, the facet element having a front surface optically used during operation of the facet mirror device and a rear surface comprising a curved first support section, and the support element having a second support section.
• the facet element is placed onto the support element such that the second support section contacts the first support section in a region of contact to support the facet element.
• a negative pressure is generated, the negative pressure acting on a part of the rear surface of the facet element such that the first support section is pressed against the second support section.
• Figure 1 is a schematic representation of a preferred embodiment of an optical imaging arrangement according to the invention which comprises a preferred embodiment of a facet mirror device according to the invention and with which preferred embodiments of methods according to the invention may be executed;
• Figure 2 is a schematic sectional representation of a part of a facet mirror device
• the facet mirror device being a part of the optical imaging arrangement of Figure 1 (in a section along line VII-VII of Figure 8);
• Figure 3 is a schematic sectional representation of the detail III of Figure 2;
• Figure 4 is a schematic sectional representation of the part of the facet mirror device of
• Figure 5 is a schematic sectional representation of the part of the facet mirror device of
• Figure 6 is a schematic sectional representation of the part of the facet mirror device of
• Figure 7 is a schematic sectional representation of the facet mirror device of Figure 2 to 6
• Figure 8 is a schematic top view of the facet mirror device of Figure 2 to 7;
• Figure 9 is a schematic top view of a part of the support element the facet mirror device of
• Figure 10 is a block diagram of a preferred embodiment of a method of manufacturing a facet mirror device comprising a preferred embodiment of a method of supporting the facet element according to the invention which may be used for the optical imaging arrangement of Figure 1.
• Figure 1 1 is a schematic sectional representation of a detail of a further preferred
• Figure 12 is a schematic sectional representation of the detail of Figure 1 1 in a second manufacturing stage
• Figure 13 is a schematic top view of a part of the support element the facet mirror device of
• FIG 1 is a schematic and not-to-scale representation of the optical imaging arrangement in the form of an optical exposure apparatus 101 used in a microlithography process during manufacture of semiconductor devices.
• the optical exposure apparatus 101 comprises an illumination unit 102 and an optical projection unit 103 adapted to transfer, in an exposure process, an image of a pattern formed on a mask 104.1 of a mask unit 104 onto a substrate 105.1 of a substrate unit 105.
• the illumination unit 102 illuminates the mask 104.1 .
• the optical projection unit 103 receives the light coming from the mask 104.1 and projects the image of the pattern formed on the mask 104.1 onto the substrate 105.1 , e.g. a wafer or the like.
• the illumination unit 102 comprises an optical element system 106 (only shown in a highly simplified manner in Figure 1 ) including a plurality of optical element units such as optical element unit 06.1.
• the optical element unit 106.1 is formed as a preferred embodiment of a facet mirror device according to the invention.
• the optical projection unit 103 comprises a further optical element system 107 including a plurality of optical element units 107.1.
• the optical element units of the optical element systems 106 and 107 are aligned along a folded optical axis 101.1 of the optical exposure apparatus 101.
• the optical exposure apparatus 101 operates using light in the EUV range at a wavelength between 5 nm to 20 nm, more precisely at a wavelength of 13 nm.
• the optical elements used within the illumination unit 102 and the optical projection unit 103 are exclusively reflective optical elements.
• any type of optical elements may be used alone or in an arbitrary combination.
• the optical element system 107 may comprise a further facet mirror device according to the invention.
• the facet mirror device 106.1 comprises a support element 108 supporting a plurality of facet elements 109.
• facet elements 109 are supported on the support element 108.
• at any other number of facet elements 109 may be carried by the support element 108.
• up to 2000 facet elements 109 or even more are supported on the support element 108.
• the facet elements 109 are arranged such that a small gap of less than 0.05 mm is left between them.
• a regular rectangular matrix of facet elements 109 is formed on the support element 108 providing a minimum amount of loss in radiant power.
• any other arrangement of facet elements may be chosen according to the optical needs of the imaging device, the facet mirror device is used for.
• each facet element 109 in a top view (along the z-direction), has an outer contour of substantially rectangular shape, more precisely of substantially squared shape.
• any other geometry of this outer contour may be chosen such as, for example, an arbitrarily curved outer contour, a circular outer contour, an elliptic outer contour, a polygonal outer contour or arbitrary combinations thereof.
• each facet element has a concave front surface 109.1 , a convex rear surface 109.2 and a lateral surface 109.3.
• the front surface 109.1 is a reflective surface optically used during operation of the optical imaging arrangement 101 in order to provide homogenization of the exposure light provided by the illumination unit 102.
• the reflective surface 109.1 may be provided via a reflective coating applied to the front surface 109.1 which is adapted to the wavelength of the exposure light used (typically, in order to provide maximum reflectivity at the respective wavelength).
• the front surface 109.1 is a spherical surface.
• any other shape of the front surface may be chosen depending on the optical task to be performed by the facet mirror device.
• aspherical as well as planar surfaces as well as arbitrary combinations thereof may be used.
• convex front surfaces may also be used.
• the rear surface 109.2 also is a spherical surface which is free from any protrusions radially protruding beyond this spherical surface defined by the first support section 109.4 of the rear surface 109.2.
• this has the advantage that the parts of the rear surface 109.2 contacting the support element 108 (i.e. the first support section 109.4) and the parts of the rear surface 109.2 reaching into the recess 108.3 may be easily produced in a typical, well-established lens manufacturing process providing excellent accuracy of the rear surface 109.2.
• the radius of curvature of the front surface 109.1 and the rear surface 109.2, the outer contour of the lateral surface 109.3, the centering of the facet element 109, the central as well as the lateral thickness (dimension in the z-direction) may be manufactured at a very high precision using such conventional lens manufacturing techniques.
• a part of the rear surface 109.2 of the facet element 09 forms a spherical first support section 109.4 contacting a second support section formed by a support edge 108.1 of the support element 108.
• the support edge 108.1 is formed at an end of a cylindrical wall 108.2 confining a cylindrical recess 108 3 within the support element 108.
• the recess 108.3 is of circular cross-section, such that the curvature of the support edge 08.1 in the xy-plane corresponds to the curvature of the rear surface 109.2 in the region of contact between the first support section 109.4 and the second support section, i.e. the support edge 108.1 .
• the support edge 108.1 is formed as a sharp edge having an edge radius, i.e. a minimum radius of curvature, which is less than 0.5 mm to 3 mm.
• the edge radius ranges from 1 .0 mm to 2.0 mm. This minimum radius of curvature is measured in a radial plane which, in the embodiment shown, contains the axis 108.4 of the recess 108.3.
• the edge radius is about 5% to 20%, preferably about 10% to 15%, of the maximum dimension of the facet element 109 in its plane of main extension (here: xy-plane). In the embodiment shown, this maximum dimension is about 5 mm to 10 mm, although smaller or larger dimensions may be chosen depending on the optical requirements for the facet mirror device.
• Such a sharp support edge 108.1 has the advantage that the support edge 108.1 may be easily manufactured at very high precision.
• the only comparatively simple manufacturing steps to be taken are to provide the cylindrical recess 108.3 and a planar upper surface 108.5 of the support element 108. Both operations may be comparatively easily performed at very high precision.
• high precision manufacturing techniques such as chemical-mechanical polishing (CMP), pitch polishing, magneto- rheological fluid polishing (MRFP) and robotic polishing may be used when producing the support edge 108.1.
• a distance tolerance between axes 108.4 of adjacent recesses 108.3 of a few microns, typically about 5 pm. may be obtained.
• the angular deviation of the axis 108.4 from a surface normal on the upper surface 108.5 is less than 0.005°.
• a width GW of a manufacturing tolerance related local gap between the support edge 108.1 and the rear surface 109.2 of the facet element 109 is less than 0.5 pm to 10 pm, preferably less than 1 ⁇ to 5 ⁇ As shown in Figure 3, this gap width GW is the dimension in a direction of a surface normal of the rear surface 109.2 extending through the respective edge point.
• the facet mirror device 106.1 is manufactured according to a preferred embodiment of the method according to invention using a preferred embodiment of the method of supporting a facet element according to the invention.
• the support element 108 and the facet elements 109 are manufactured as it has been outlined above.
• the facet elements are made of silicon (Si), while the support element is made of silicon carbide (SiC). With such a material pairing and beneficial heat transfer from the facet elements 109 (typically reaching temperatures of 100°C to 150°C during operation of the imaging arrangement 101 ) may be obtained.
• the facet element may be made of silicon carbide (SiC), quartz (Si0 2 ), nickel plated copper or steel, while the support element may be made of silicon infiltrated silicon carbide (SiSiC) or tungsten carbide (WC).
• a facet element 109 is placed from above along the z-direction on the support edge 108.1 (using a suitable handling device not shown) after a ring of an adhesive bonding material 1 13 has been placed on the upper surface 108.5 of the support element 108 adjacent to the support edge 108.1 (see Figure 4).
• a negative pressure is generated within the recess 108.3 using a suction device 114 controlled by a control device 1 15.
• the suction device 1 14 is connected to a connector 1 16 which in turn is connected to a connector section 108.6 of the wall 108.2.
• This negative pressure within the recess 108.3 has the effect that the rear surface 109.2 of facet element 109 is pressed against the support edge 108.1 holding the facet element in place without any need for additional manipulators, clamping devices etc.
• the high precision of the support edge 108.1 and the rear surface 109.2 themselves already guarantee that even only a slight negative pressure within the recess 108.3 is sufficient to reliably generate a well-defined line load between the support edge 108.1 and facet element 109 reliably holding the latter in place.
• the negative pressure generated by the suction device 1 14 provides proper holding forces holding the facet element 109 in place.
• the suction device 1 14 generates a pressure of about
• any other pressure level may be provided in the recess, the pressure level being selected as a function of the forces to be generated for holding the facet element in place.
• the viscosity of the adhesive material 1 13 may be selected sufficiently high to avoid excess intake of adhesive material 1 13 into the recess 108.3 through such eventual gaps.
• the adhesive material forms a sealing ring (at least predominantly) located outside the recess 108.3 (i.e. on a side of the support edge 108.1 facing away from the recess 108.3) and surrounding the contact region between the facet element 109 and the support element 108 (see e.g. Figures 2 and 4 to 7).
• an adjustment step 1 12.4 of the supporting step 1 12.2 the orientation of the facet element 109 with respect to the support element 108 is adjusted according to the optical requirements for the facet mirror device 106.1 during later operation in the imaging arrangement 101.
• a contactless manipulator 1 17 controlled by the control device 1 15 is used to generate a corresponding adjustment force on the front surface 109.1 of the facet element 109 as it is shown in Figure 5.
• the manipulator is a pneumatic manipulator generating a jet of air 117.1 expelled towards the front surface 09.1 thereby exerting an adjustment force on the facet element 109.
• a relative motion may be generated between the manipulator 1 17 and the facet mirror device 106.1 is such that the manipulation force F generated by the jet of air 1 17.1 may act on the facet element 109 at the appropriate location to provide proper adjustment of the latter.
• any other contactless or contact type manipulator such as a tactile manipulator, a cantilever spring manipulator etc
• any other contactless or contact type manipulator such as a tactile manipulator, a cantilever spring manipulator etc
• an acoustic manipulator may be used generating standing acoustic waves, the acoustic pressure of which generating the manipulating force F acting on the facet element.
• the measurement device 1 18 is an optical device comprising an emitter 1 18.1 emitting a measurement light beam 1 18.2 towards the front surface 109.1.
• the measurement light beam 1 18.2 is reflected at the front surface 109.1 and reaches a sensor 1 18.3 of the measurement device 1 18.
• the emitter is a conventional emitter using measurement light at a wavelength of 633 nm.
• the emitter may be necessary to provide a measurement section 1 19 at the front surface 109.1 having a reflective coating adapted to this wavelength of the measurement light (provided that the reflective coating of the front surface 109.1 adapted to the exposure light does not provide sufficient reflection at the measurement light
• the signals of the sensor 1 18.3 are forwarded to the control device 1 15 which, in turn, performs the assessment of the adjustment of the front surface 109.1 using these signals. It will be appreciated that the control device 1 15, as a function of the signals of the sensor 118.3, controls the suction device 1 14 and the manipulator 1 17 to provide rapid proper adjustment of the front surface 109.1.
• the front surface 109.1 is adjusted at an angular accuracy of less than 100 prad.
• any other angular accuracy may be chosen.
• the negative pressure within the recess 108.3 may be reduced to reduce the holding force exerted on the facet element 109. This in turn reduces the amount of the manipulation force to be exerted by the manipulator 1 17 in order to achieve an adjustment movement of the front surface 109.1.
• the control device 1 15 may cause the suction device 1 14 to increase the negative pressure to securely hold the facet element in place.
• this suction device 1 14 forms a holding device generating the negative pressure in the recess 108.3 which in a very simple, contactless manner generates a stabilizing contact force between the facet element 09 and the support element 108.
• This contact force in turn leads to an adjustable resistance against dislocation of the facet element 109 without any risk of dislocating the facet element 109 due to a malfunction of the holding device.
• this stabilizing effect may be achieved in a very simple manner using the specific design of the support element 108 with the support edge 108.1 as outlined above.
• the inventive concept of generating a negative pressure acting on the facet element to hold the latter in place is independent of the design of the cooperating support sections of the support element and the facet element as long as a sufficiently air tight connection between the support sections is exists such that the negative pressure may generate the stabilizing contact force between the support element and the facet element.
• the facet element 109 is fixed in place by curing the adhesive bonding material 1 13 such that a fixed adhesive connection is established between the facet element 109 and the support element 108.
• any other suitable bonding technique may be used alone or in arbitrary combination to provide proper connection and relative fixation between the facet elements and the support element.
• suitable bonding techniques include, for example, soldering, laser soldering, welding, laser welding, diffusion bonding etc. It will be appreciated that, if diffusion bonding is used, the negative pressure in the recess 108.3 may be increased to at least support the contact pressure needed in the bonding process.
• the bonding material 1 13 may also be applied at any point in time during or after the adjustment of the facet element as it has been outlined above.
• the adhesive material 13 may be selected to have a high thermal conductivity such that good heat transfer from the facet element 109 to the support element 108 achieved. Furthermore, in cases where high thermal conductivity of the bond between the facet element and the support element is crucial, other bonding techniques (e.g. soldering, welding, diffusion bonding) providing better heat transfer may be used.
• step 112.6 it is then checked if a further facet element 109 is to be mounted to the support element 108. If this is the case the method jumps back to step 1 12.3 for executing the supporting step for the next facet element 109 to be mounted. Otherwise, the method ends in step 112.7
• the recess 108.3 may be filled with a liquid heat transfer medium having high thermal conductivity to improve heat transfer from the facet element 109 to the support element 108.
• the recess 108.3 may be sealed using a cap 120 as it is shown in Figure 2.
• the cap 120 may be provided with an elastic portion compensating thermal expansion of the heat transfer medium by elastic deformation as it is indicated in Figure 2 by the contours 120.1 and 120.2.
• this introduction of a heat transfer medium into the respective recess 108.3 may be a one-time operation since the ring-shaped adhesive material 1 13 and the cap 120 provide long-term sealing of the recess 108.3.
• regular exchange refill of the heat transfer medium may be provided (e.g. via the cap 120) if necessary.
• Heat removal from the facet mirror device 106.1 during operation of the imaging arrangement 101 may be achieved using a cooling medium circulating through cooling channels as they are indicated by the dashed contours 121 (see e.g. Figures 2 to 6).
• the respective recess 108.3 itself forms part of a cooling channel system, wherein, during operation of the imaging arrangement 101 , a cooling medium is circulated by a cooling device 122 (controlled by the control device 115) connected to the recess 108.3 via the connector 1 16 as it is shown in Figure 6.
• repair and exchange of one or more facet elements 109 may be executed using repair variants of the methods as outlined above.
• a thermal load may be applied to the respective facet element 109 to be repaired or exchanged. This thermal load is selected to cause a sufficiently high and/or rapid thermal expansion difference between the facet element 109 and the support element 108 causing failure (e.g. fracture or
• the facet element 109 may then be removed from the support element 108. This step may be repeated for any facet element 109 to be removed.
• the support element may be worked (e.g. removing any residue of the broken or disintegrated bonding material 1 13) in order to allow mounting of replacement facet element 109.
• the method may proceed to step 1 12.2 and be executed as it has been outlined above to mount a replacement facet element 109 for any facet element 109 removed previously.
• the facet mirror device 206.1 in its basic design and functionality largely corresponds to the facet mirror device 106.1 and may replace the facet mirror device 106.1 in the optical imaging device 101 of Figure 1.
• the method of supporting a facet element and the method of manufacturing the facet mirror device as they have been described above in relation to the first embodiment ( Figure 10) may be executed as well in the context of this facet mirror device 206.1.
• it is here mainly referred to the explanations given above and only the differences with respect to the facet mirror device 106.1 will be explained in further detail.
• similar parts are given the same reference numeral raised by the amount 100 and (unless explicitly described in the following) in respect to these parts reference is made to the explanations given above in the context of the first embodiment.
• the support edge 208.1 is provided with eight small radial slots 208.7 (evenly distributed at the circumference of the support edge 208.1 ).
• the support edge 208.1 is a segmented edge comprising eight support edge segments 208.8 mutually separated by one of the radial slots 208.7.
• any other number and/or arrangement of the radial slots may be chosen.
• the dimensions of the respective radial slot 208.7, the viscosity of the adhesive material 1 13 and the negative pressure are mutually adapted such that, on the one hand, the adhesive material is partially drawn into the respective slot 208.7 about that, on the other hand, no substantial intake of adhesive material 1 13 into the recess 208.3 takes place.
• Such a configuration has the advantage that a comparatively large surface of both the support element of 208 and the rear surface 109.2 of the facet element 109 is reliably and fully wetted by the adhesive material leading to a good adhesive contact between the adhesive material 1 13 and the facet element 109 and the support element 208, respectively.
• first support section on the rear surface of the facet element is a spherical surface while the support edge is a planar circular edge.
• any other design with mating (arbitrary) curvatures between the first support section and the support edge may be chosen.
• a configuration may be chosen wherein the first support section on the rear surface of the facet element is a cylindrical surface contacting a curved support edge (substantially extending along the circumference of the cylindrical surface).
• the cylindrical surface of the first support section may contact at least one straight support edge (substantially extending parallel to the longitudinal axis of the cylindrical surface).
• the invention has been described in the context of embodiments where the optical module according to the invention is used in the illumination unit. However, it will be appreciated that the optical module according to the invention may provide its beneficial effects as well in the optical projection unit.
• the invention has been described in the context of embodiments working in the EUV range. However, it will be appreciated that the invention may also be used at any other wavelength of the exposure light, e.g. in systems working at 193 nm etc. Finally, in the foregoing, the invention has been described solely in the context of microlithography systems. However, it will be appreciated that the invention may also be used in the context of any other optical device using facet mirror devices.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Health & Medical Sciences (AREA)
• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Epidemiology (AREA)
• Public Health (AREA)
• Optical Elements Other Than Lenses (AREA)
• Mounting And Adjusting Of Optical Elements (AREA)
• Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)
• Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)

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• 2010
  • 2010-07-28 WO PCT/EP2010/060955 patent/WO2012013227A1/en not_active Ceased
  • 2010-07-28 JP JP2013520975A patent/JP5738410B2/ja not_active Expired - Fee Related
  • 2010-07-28 CN CN201080069330.6A patent/CN103140782B/zh not_active Expired - Fee Related
• 2011
  • 2011-07-08 TW TW100124197A patent/TWI459047B/zh not_active IP Right Cessation
• 2013
  • 2013-01-18 US US13/744,943 patent/US9599910B2/en not_active Expired - Fee Related

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