WO2014180931A1 - Agencement d'élément optique comportant un élément optique divisé en sous-éléments optiques - Google Patents

Agencement d'élément optique comportant un élément optique divisé en sous-éléments optiques Download PDF

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Publication number
WO2014180931A1
WO2014180931A1 PCT/EP2014/059395 EP2014059395W WO2014180931A1 WO 2014180931 A1 WO2014180931 A1 WO 2014180931A1 EP 2014059395 W EP2014059395 W EP 2014059395W WO 2014180931 A1 WO2014180931 A1 WO 2014180931A1
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WIPO (PCT)
Prior art keywords
metrology
optical
optical element
component
sub
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PCT/EP2014/059395
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English (en)
Inventor
Yim-Bun Patrick Kwan
Jamie Eisinger
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Carl Zeiss Smt Gmbh
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Publication of WO2014180931A1 publication Critical patent/WO2014180931A1/fr

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    • 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
    • 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
    • G03F7/70833—Mounting of optical systems, e.g. mounting of illumination system, projection system or stage systems on base-plate or ground
    • 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
    • G03F7/70858—Environment aspects, e.g. pressure of beam-path gas, temperature
    • G03F7/709—Vibration, e.g. vibration detection, compensation, suppression or isolation

Definitions

  • the invention relates to optical element arrangements and optical imaging arrangements used in exposure processes, in particular to optical element arrangements of
  • microlithography systems It further relates to a method of capturing a position and an orientation of an optical element. It also relates to a method of transferring an image of a pattern onto a substrate.
  • 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 units comprising optical elements, such as lenses and mirrors etc., arranged in the light path of the optical system.
  • Those optical elements usually cooperate in an exposure process to transfer an image of a pattern formed on a mask, reticle or the like onto a substrate such as a wafer.
  • Said optical elements are usually combined in one or more functionally distinct optical element groups. These distinct optical element groups may be held by distinct optical exposure units.
  • such optical exposure units are often built from a stack of optical element modules holding one or more optical elements.
  • optical element modules usually comprise an external generally ring shaped support device supporting one or more optical element holders each, in turn, holding an optical element.
  • Optical element groups comprising at least mainly refractive optical elements, such as lenses, mostly have a straight common axis of symmetry of the optical elements usually referred to as the optical axis.
  • the optical exposure units holding such optical element groups often have an elongated substantially tubular design due to which they are typically also referred to as lens barrels.
  • NA numerical aperture
  • One approach to achieve enhanced resolution is to reduce the wavelength of the light used in the exposure process.
  • EUV extreme ultraviolet
  • approaches have been made to use light in the extreme ultraviolet (EUV) range using wavelengths ranging from 5 nm to 20 nm, typically about 13 nm.
  • EUV range it is not possible to use common refractive optics any more. This is due to the fact that, in this EUV range, the materials commonly used for refractive optical elements show a degree of absorption that is too high for obtaining high quality exposure results.
  • reflective systems comprising reflective elements such as mirrors or the like are used in the exposure process to transfer the image of the pattern formed on the mask onto the substrate, e.g. the wafer.
  • the above leads to very strict requirements with respect to the relative position between the components participating in the exposure process. Furthermore, to reliably obtain high-quality semiconductor devices it is not only necessary to provide an optical system showing a high degree of imaging accuracy at a certain point in time. It is also necessary to maintain such a high degree of accuracy throughout the entire exposure process and over the lifetime of the system. As a consequence, the optical imaging arrangement components, i.e. the mask, the optical elements and the wafer, for example, cooperating in the exposure process must be supported in a defined manner in order to maintain a predetermined spatial relationship between said optical imaging arrangement components as well to provide a high quality exposure process.
  • the optical imaging arrangement components i.e. the mask, the optical elements and the wafer, for example, cooperating in the exposure process must be supported in a defined manner in order to maintain a predetermined spatial relationship between said optical imaging arrangement components as well to provide a high quality exposure process.
  • an increase in the numerical aperture typically, leads to an increased size of the optical elements used, also referred to as the optical footprint of the optical elements.
  • the optical footprint of the optical elements In some cases, comparatively large optical elements having an optical footprint of up to 1 m x 1 m may be required.
  • the increased optical footprint of the optical elements used has a negative impact on their dynamic properties and the control system used to achieve the above adjustments.
  • a large optical element irrespective of the so-called aspect ratio (i.e. the thickness to diameter ratio) of the optical element, a large optical element generally exhibits low resonant frequencies. While, for example, a mirror with an optical footprint of 150 mm (in diameter) and a thickness of 25 mm typically has resonant frequencies above 4000 Hz, a mirror with an optical footprint of 700 mm (in diameter), typically, hardly reaches resonant frequencies above 1500 Hz even at a thickness of 200 mm. Furthermore, increased size and weight of the optical elements also means increased static deformation due to variations of the gravitational constant at different locations all over the world, which impairs imaging performance when uncorrected.
  • a relaxation of the building space constraints while maintaining the measurement accuracy (and, ultimately, the control accuracy) may be achieved if three metrology units are used, wherein the respective metrology components associated to the respective optical sub element are located, both, in the area of the sub element defining the outer circumference of the optical element and at least two of these metrology components are located at least close to their maximum distance technically achievable in the circumferential plane and/or in a direction perpendicular to this circumferential plane.
  • Such a placement of the metrology components at the outer circumference of the optical element has the advantage that these components are more easily accessible, e.g. for later calibration and fine adjustment, respectively. Furthermore, support of the associated further component of the respective metrology unit is greatly facilitated compared to conventional designs where the support structure has to reach up to the rear part of the optical element close to the area of the point of interest (POI).
  • POI point of interest
  • an optical element arrangement comprising an optical element unit and a metrology arrangement, the optical element unit comprising a support structure supporting an optical element.
  • the optical element has an outer circumference defining a circumferential direction, said circumferential direction defining a circumferential plane.
  • the optical element has an optical surface adapted to participate in an exposure process transferring an image of a pattern onto a substrate.
  • the optical element is split into a plurality of optical sub-elements, each optical sub-element having an optical surface section and a circumferential section.
  • Each optical sub-element is supported by the support structure to form said optical surface of the optical element from the optical surface sections and to form the outer circumference of the optical element from the circumferential sections.
  • At least one actively supported optical sub- element of the optical sub-elements under the control of a control device connected to the metrology arrangement, is actively supported by the support structure.
  • the metrology arrangement comprises a metrology device adapted to capture a position and/or an orientation of the actively supported optical sub-element in up to six degrees of freedom using at least a first metrology unit with a first metrology component, a second metrology unit with a second metrology component and a third metrology unit with a third metrology component, all associated to the actively supported optical sub-element.
  • the metrology components are connected to the optical sub-element in the area of the circumferential section of the actively supported optical sub-element.
  • the circumferential section of the actively supported optical sub-element, the first metrology unit and the second metrology unit, in a first direction parallel to the circumferential plane, define a maximum technically feasible first distance between the first metrology component and the second metrology component.
  • the circumferential section of the actively supported optical sub- element and the metrology units in a second direction perpendicular to the circumferential plane, define a maximum technically feasible second distance between the metrology components.
  • the first metrology component and the second metrology component, in the first direction are located at a third distance that is at least 80% to 90%, of the first distance.
  • at least one of the first metrology component and the second metrology component, in the second direction are located at a fourth distance from the third metrology component that is at least 80% to 90% of the second distance.
  • a method of capturing a position and orientation of an optical element comprises supporting the optical element, the optical element having an outer circumference defining a circumferential direction, the circumferential direction defining a circumferential plane, the optical element having an optical surface adapted to participate in an exposure process transferring an image of a pattern onto a substrate.
  • Supporting the optical element comprises splitting the optical element into a plurality of optical sub-elements, each optical sub-element having an optical surface section and a circumferential section, and supporting each optical sub- element to form the optical surface of the optical element from the optical surface sections and to form the outer circumference of the optical element from the circumferential sections.
  • Supporting the optical element further comprises actively supporting at least one actively supported optical sub-element of the optical sub-elements, under the control of a control device connected to a metrology arrangement.
  • the method further comprises, via a metrology device of a metrology arrangement, capturing a position and an orientation of the actively supported optical sub-element in up to six degrees of freedom using at least a first metrology unit with a first metrology component, a second metrology unit with a second metrology component and a third metrology unit with a third metrology component, all associated to the actively supported optical sub-element, the metrology components being connected to the optical sub-element in the area of the circumferential section of the actively supported optical sub-element.
  • the circumferential section of the actively supported optical sub-element, the first metrology unit and the second metrology unit, in a first direction parallel to the circumferential plane, define a maximum technically feasible first distance between the first metrology component and the second metrology component.
  • the the circumferential section of the actively supported optical sub-element and the metrology units, in a second direction perpendicular to the circumferential plane, define a maximum technically feasible second distance between the metrology components.
  • the first metrology component and the second metrology component, in the first direction are located at a third distance that is at least 80% to 90%, of the first distance.
  • at least one of the first metrology component and the second metrology component, in the second direction are located at a fourth distance from the third metrology component that is at least 80% to 90% of the second distance.
  • a method of transferring an image of a pattern onto a substrate comprising in a transferring step, transferring the image of the pattern onto the substrate using an optical imaging arrangement, in a capturing step of the transferring step, capturing a position and orientation of an optical element of the optical imaging arrangement using the method according to the invention and, in a controlling step of the transferring step, controlling at least one of a position and an orientation of at least one component of the optical imaging arrangement as a function of the spatial relationship captured in the capturing step.
  • Figure 1 is a schematic representation of a preferred embodiment of an optical imaging arrangement comprising an optical element arrangement according to the invention with which preferred embodiments of methods according to the invention may be executed;
  • Figure 2 is a schematic top view of an optical element of the optical element arrangement of Figure 1 ;
  • Figure 3 is a schematic enlarged top view of an optical sub-element of the optical element arrangement of Figure 1 ;
  • Figure 4 is a schematic perspective view of the optical sub-element of Figure 3;
  • Figure 5 is a schematic perspective view of an optical sub-element of a further preferred embodiment of an optical element arrangement according to the invention.
  • Figure 6 is a schematic perspective view of an optical sub-element of a further preferred embodiment of an optical element arrangement according to the invention.
  • Figure 7 is a schematic perspective view of an optical sub-element of a further preferred embodiment of an optical element arrangement according to the invention.
  • Figure 1 is a highly schematic and not-to-scale representation of the optical imaging arrangement in the form of an optical exposure apparatus 101 operating in the EUV range at a wavelength of 13 nm.
  • the optical exposure apparatus 101 comprises a preferred embodiment of an optical element arrangement according to the invention in the form of an optical projection unit 102 adapted to transfer an image of a pattern formed on a mask 103.1 (located on a mask table 103.2 of a mask unit 103) onto a substrate 104.1 (located on a substrate table 104.2 of a substrate unit 104).
  • the optical exposure apparatus 101 comprises an illumination system 105 illuminating the reflective mask 103.1 via an appropriate light guide system (not shown).
  • the optical projection unit 102 receives the light (represented by its chief ray 105.1 ) reflected from the mask 103.1 and projects the image of the pattern formed on the mask 103.1 onto the substrate 104.1 , e.g. a wafer or the like.
  • the optical projection unit 102 holds an optical element unit group 106 of optical element units 106.1 to 106.6.
  • This optical element unit group 106 is held within a support structure 102.1.
  • the support structure 102.1 may take the form of a housing of the optical projection unit 102, which, in the following, is also referred to as the projection optics box (POB) 102.1. It will be appreciated, however, that this support structure does not necessarily have to form a complete or tight enclosure of the optical element unit group 106. Rather it may also be partially formed as an open structure.
  • the projection optics box 102.1 is supported in a vibration isolated manner on a base structure 107 which also supports the mask table 103.2 via a mask table support device 103.3 and the substrate table 104.2 via a substrate table support device 104.3. It will be appreciated that the projection optics box 102.1 may be supported in a cascaded manner via a plurality of vibration isolation devices and at least one intermediate support structure unit to achieve good vibration isolation. Generally, these vibration isolation devices may have different isolation frequencies to achieve good vibration isolation over a wide frequency range.
  • the optical element unit group 106 comprises a total of six optical element units, namely a first optical element unit 106.1 , a second optical element unit 106.2, a third optical element unit 106.3, a fourth optical element unit 106.4, a fifth optical element unit 106.5 and sixth optical element unit 106.6.
  • each of the optical element units 106.1 to 106.6 consists of an optical element in the form of a mirror.
  • the respective optical element unit may also comprise further components (beyond the optical element itself) such as, for example, aperture stops, holders or retainers holding the optical element and eventually forming an interface for the support unit connecting the optical element unit to the support structure.
  • optical element units may be used. Preferably, four to eight optical element units are provided.
  • Each one of the mirrors 106.1 to 106.6 is supported on the support structure formed by the projection optics box 102.1 by an associated support device 108.1 to 108.6.
  • Each one of the support devices 108.1 to 108.6 is formed as an active device such that each of the mirrors 106.1 to 106.6 is actively supported at a defined control bandwidth.
  • the optical element unit 106.6 is a large and heavy component forming a first optical element unit of the optical element unit group 106 while the other optical element units 106.1 to 106.5 form a plurality of second optical element units of the optical element unit group 106.
  • the first optical element unit 106.6 is actively supported at a first control bandwidth
  • the second optical element units 106.1 to 106.5 are actively supported at a second control bandwidth to substantially maintain a given spatial relationship of each of the second optical element units 106.1 to 106.5 with respect to the first optical element unit 106.6 as will be explained further below.
  • a similar active support concept is chosen for the mask table support device 103.3 and the substrate table support device 104.3 both also actively supported at a third and fourth control bandwidth, respectively, to substantially maintain a given spatial relationship of the mask table 103.2 and the substrate table 104.2, respectively, with respect to the first optical element unit 106.6. It will be appreciated however that, with other embodiments of the invention, another support concept may be chosen for the mask table and/or the substrate table.
  • control of the active support devices 108.1 to 108.6, 103.3 and 104.3 is performed by a control unit 109 as a function on the signals of a metrology arrangement 110 capturing the position and the orientation of the respective optical element unit 106.1 to 106.6, the mask table 103.2 and the substrate table 104.2 in all six degrees of freedom (DOF).
  • the control unit 109 is connected to and provides corresponding control signals to each one of the support devices 108.1 to 108.6, 103.3 and 104.3 (as it is indicated in Figure 1 by the solid and dotted lines at the control unit 109 and the respective support device) at the specific adjustment control bandwidth as outlined above.
  • the metrology arrangement 110 uses a metrology system 110.1 comprising a plurality of metrology devices 110.2 mechanically connected to a metrology structure which in turn is supported by the projection optics box structure 102.1 as it is (highly schematically) indicated in Figure 1.
  • each metrology device 110.2 comprises at least one metrology unit 1 10.3, 110.4, 110.5 connected to the metrology structure and cooperating with a metrology component in the form of a reference element 1 10.6 mechanically connected directly to the mirror 106.6.
  • the term "mechanically connected directly”, in the sense of the invention, is to be understood as a direct connection between two parts including (if any) a short distance between the parts allowing to reliably determine the position of the one part by measuring the position of the other part.
  • the term may mean without the interposition of further parts introducing uncertainties in the position determination, e.g. due to thermal or vibration effects.
  • the reference element may not be a separate component connected to the mirror but many be directly or integrally formed on a surface of the mirror, e.g. as a grating or the like formed in a separate process upon manufacture of the mirror.
  • the metrology devices 1 10.2 at least partially operate according to an encoder principle, i.e.
  • the sensor head 110.3 emits a sensor light beam towards a structured surface and detects a reading light beam reflected from the structured surface of the reference element 110.6.
  • the structured surface may be, for example, a grating comprising a series of parallel lines (one-dimensional grating) or a grid of mutually inclined lines (two-dimensional grating) etc. Positional alteration is basically captured from counting the lines passed by the sensor beam which may be derived from the signal achieved via the reading beam.
  • any other type of contactless measurement principle such as e.g. an interferometric measurement principle, a capacitive measurement principle, an inductive measurement principle etc
  • any suitable contact based metrology arrangement may be used as well.
  • contact based working principles magnetostrictive or electrostrictive working principles etc may be used for example.
  • the choice of the working principle may be made as a function of the accuracy requirements.
  • the metrology device 1 10.2 associated to the sixth mirror 106.6 captures the first spatial relationship between the metrology structure and the sixth mirror 106.6.
  • the metrology devices 110.2 associated to the other components 106.1 to 106.5, 103.1 and 104.1 participating in the imaging process capture the spatial relationship between the metrology structure and the associated component 106.1 to 106.5, 103.1 and 104.1.
  • the metrology arrangement 110 determines the spatial relationship between the sixth mirror 106.6 and the respective further component 106.1 to 106.5, 103.1 and 104.1 using the first spatial relationship and the second spatial relationship.
  • Corresponding metrology signals are then provided to the control unit 109 which in turn generates, as a function of these metrology signals, corresponding control signals for the respective support device 108.1 to 108.6, 103.3 and 104.3.
  • the control unit 109 as a function of the metrology signals representative of the first spatial relationship between the metrology support structure and the sixth mirror 106.6, the control unit 109 generates corresponding control signals for the first support device 108.6 of the sixth mirror 06.6 (i.e. the first optical element unit in the sense of the present invention) to adjust the sixth mirror 106.6 at the above first adjustment control bandwidth (ranging from 5 Hz to 100 Hz, preferably from 40 Hz to 00 Hz) with respect to the metrology support structure of the metrology system 110.1.
  • first adjustment control bandwidth ranging from 5 Hz to 100 Hz, preferably from 40 Hz to 00 Hz
  • mirror 106.6 is a large optical footprint and heavy optical component (which may have an optical footprint of up to 1.5 m x 1.5 m and a mass of up to 350 kg), the optical surface 106.7 of which is adapted to participate in the exposure process transferring the image of the pattern formed on the mask 103.1 onto the substrate 104.1.
  • the mirror 106.6 has an outer circumference 106.8 defining a circumferential direction, the
  • circumferential direction in turn defining a circumferential plane (parallel to the xy plane).
  • mirror 106.6 due to its size, typically not only causes difficulties in adjustment control but also during manufacture and handling. Hence, as can be seen from Figures 2 to 4, mirror 106.6 is divided into a plurality of sub-segments, more precisely, four substantially identical sub-segments 11 1.1.
  • any other number of sub-segments may be chosen. Moreover, at least some of these sub segments are not necessarily identical. More precisely, any desired segmentation of the optical element 106.6 may be chosen.
  • Each sub-segment 11 1.1 is much smaller in size than the optical element 106.6, which is not only advantageous from the point of view of control dynamics but also much easier to handle during its own manufacture as well as during assembly of the optical projection unit 102.
  • each optical sub-element 1 11.1 has an optical surface section 1 11.2 and a circumferential section 1 11.3, each optical sub-element 111.1 being supported by the projection optics box 102.1 and the associated active support device 108.6 to form the optical surface 106.7 of mirror 106.6 from the optical surface sections 111.2 and to form the outer circumference 106.8 of the mirror 106.6 from the circumferential sections 1 11.3.
  • the optical sub-elements 1 11.1 are actively supported by the components of the active support device 108.6 under the control of the control device 109 connected to the metrology arrangement 110.
  • the metrology device 1 10.2 of the metrology arrangement 1 comprises a first metrology unit 110.3, a second metrology unit 110.4 and a third metrology unit 110.5, together capturing the position and orientation of the optical sub-element 111.1 in all six degrees of freedom (DOF).
  • the first metrology unit 110.3 comprises a first sensor head 1 12.1 and an associated first metrology component 1 12.2 in the form of one the reference elements 1 10.6.
  • the second metrology unit 10.4 comprises a second sensor head 112.3 and an associated second metrology component 1 12.4 in the form of one of the reference elements 110.6.
  • the third metrology unit 1 10.4 comprises a third sensor head 112.5 and an associated third metrology component 1 12.6 in the form of one of the reference elements 110.6.
  • Each of the first to third metrology components 112.2, 112.4 and 1 12.6 is connected to the optical sub-element 111.1 in the area of the circumferential section 111.3, more precisely at the circumferential section 11 1.3, of the optical sub-element 111.1.
  • 1 10.3 and 1 10.4, in a first direction parallel to the circumferential plane (xy plane) define a maximum technically feasible first distance D1 between the first metrology component 112.2 and the second metrology component 112.4.
  • the metrology units 1 10.3, 110.4 and 1 10.5 in a second direction perpendicular to the circumferential plane (xy plane), define a maximum technically feasible second distance D2 between the metrology components 112.2, 112.4 and 1 12.6.
  • the first metrology component 1 12.2 and the second metrology component 112.4, in said first direction, are located at a third distance D3 that is at about 90% of the first distance D1. Furthermore, as can be seen from Figure 4, the first metrology component 112.2 and the second metrology component
  • the first metrology component 1 12.2 and the second metrology component 112.4, in the second direction, are located at a fourth distance D4 from the third metrology component 1 12.6 that is about 80% of the second distance D2.
  • the respective distance between the first, second and third metrology components 112.2, 112.4 and 1 12.6 is selected to be close (preferably as close as technically feasible) to their mutual maximum technically feasible distance D1 and D2, respectively, at the circumferential section 1 11.3.
  • the first metrology component 112.2 and the second metrology component 112.4 in the second direction, are located substantially at the same level to achieve the desired maximization of the mutual distances between the metrology components 112.2, 1 12.4 and 1 12.6. It will be appreciated that, with other embodiments of the invention, the first metrology component 112.2 and the second metrology component 112.4 may also be located at different levels (in the second direction). However, preferably, they are located at a fifth distance D5 that is less than 10% to 20% of the second distance D2.
  • the third metrology component 112.6 in the first direction, is located substantially halfway between the first metrology component 112.2 and the second metrology component 112.4.
  • the first metrology component 112.2 and the third metrology component 112.6, in the first direction are located at a sixth distance D6, while the second metrology component 1 12.4 and the third metrology component 1 12.6, in the first direction, are located at a seventh distance D7, wherein the sixth distance D6 substantially corresponds to the seventh distance D7.
  • a deviation from this substantially central arrangement of the third metrology component 112.6 between the first and second metrology components 112.2 and 112.4 may be chosen.
  • said deviation between the sixth distance D6 and the seventh distance D7 is less than 10% to 20% of the first distance D1.
  • each metrology unit 110.3 to 110.5 is adapted to capture motion of the optical sub element 1 1 1.4 in two translatory sensing directions (also referred to as measurement degrees of freedom). While the first metrology unit 1 10.3 captures sensing directions SI and S2, second metrology unit 1 10.4 captures sensing directions S3 and S4, while the third metrology unit captures sensing directions S5 and S6.
  • sensing directions S1 , S3 and S5 all are arranged substantially parallel to the x-axis, while sensing directions S2 and S4 are substantially parallel to the z- axis. Finally, sensing direction S3 is substantially parallel to the y-axis.
  • Such a configuration allows determination of the position and orientation of the optical sub element, in particular, its optical point of interest (POI), which is located at the area center of gravity (ACOG) of the area of the optical surface 106.7 optically used in exposure process, in all six degrees freedom (DOF) with sufficient accuracy.
  • POI optical point of interest
  • ACOG area center of gravity
  • sufficiently precise capturing (i.e. sufficiently high capturing sensitivity) of the motions, especially in the rotational degrees of freedom, in particular about the x-axis and the y-axis, is guaranteed by the pairwise at least largely maximized distance between the metrology components 112.2, 112.4 and 112.6. This is due to the maximum lever arm or distance between the sensing directions It will be appreciated that, preferably, the mutual distance between the components 12.2, 1 12.4 and 112.6 is maximized (i.e., pushed to the maximum technically feasible distance D1 and D2, respectively). Hence, a situation where the third distance D3 is substantially 100% of the first distance D1 and/or a situation where the fourth distance D4 is substantially 100% of the second distance D2 is generally preferred. However, as in the present example, values, deviating from this maximum by up to 20%, preferably by 10% or less, are considered acceptable as well.
  • translatory motion of the optical sub element 111.1 in the x and y direction are captured using sensing directions S5 and S6, while sensing directions S2 and S4 are used to capture translatory motion in the z direction and rotatory motion about the y axis.
  • rotatory motion about the z axis is determined from differential motions captured by sensing directions S1 and S3, while sensing directions S1 , S3 and S5 together can be used to determine rotatory motion about the x axis.
  • motion of any point on the optical sub surface 1 11.2 in particular motion of the point of interest (POI)
  • POI point of interest
  • the placement of the metrology components 112.2, 112.4 and 112.6 along with the associated sensor heads 112.1 , 1 12.3 and 12.5 at the outer circumference of the optical sub segment 111.1 not only allows easy mounting and access to these components of the metrology units 1 10.3 to 110.5 during assembly of the optical projection unit 102. It also allows a much simpler metrology support structure, typically referred to as the so-called sensor frame.
  • This metrology support structure in the present case, may be designed as simple a generally shell type structure surrounding the outer circumference of mirror 106.6.
  • a further advantage of the mutually at least largely maximized distance between the metrology units 110.3 to 110.5, is the fact that the thermal influence of the metrology units 110.3 to 1 10.5 (e.g. radiation heating) on the metrology support structure can be minimised.
  • the line of sight (LOS) sensitivities to displacement of all four sub segments 1 11.1 in combination are only half of those of a full mirror. Hence, in other words, one can allow two times the amount of capturing and adjustment error compared to a conventional monolithic mirror.
  • the capturing sensitivity of the metrology device 110.2 is further maximized due to the fact that the ones of the sensing directions S1 to S6 providing motion sensing components in the same translatory degree of freedom (such as, e.g., S1 , S3 and S5 along the x axis, as well as S2 and S4 along the y axis) are substantially parallel.
  • the sensing directions S1 and S2 of the first metrology unit 110.3 define a first measurement plane MP1
  • the sensing directions S3 and S4 of the second metrology unit 110.4 define a second measurement plane P2, which is substantially parallel to the first measurement plane MP1.
  • the sensing direction S5 of the third metrology unit 110.5 is substantially parallel to the first measurement plane MP1.
  • the first measurement plane MP1 and the second measurement plane MP2 are arranged such that the point of interest (POI) of the sub segment 111.1 is located at substantially the same distance between those measurement planes MP1 and MP2.
  • the sensing directions S5 and S6 of the third metrology unit 110.5 define a third measurement plane MPS that is substantially perpendicular to the first measurement plane MP1. All this adds to maximizing the capturing sensitivity and, hence, capturing accuracy in relation to the point of interest (POI).
  • measurement planes MP1 and MP2 may also partially be omitted, i.e. a certain inclination between the sensing directions providing motion sensing components in the same translatory degree of freedom and/or the measurement planes MP1 and MP2 may be allowed the same applies to a deviation from the described arrangement of the third measurement plane MP3 with respect to the measurement plane P1.
  • optical imaging arrangements in their basic design and functionality largely correspond to the optical imaging arrangement 101 of the first embodiment such that it is here mainly referred to the differences.
  • like components are given the same reference numeral increased by the value 100, 200 and 300, respectively.
  • explicit reference is made to be explanations given above in the context of the first embodiment with respect to these components.
  • the second embodiment shown in Figure 5 differs insofar from the first embodiment that the measurement planes P1 and MP2 (defined by the sensing directions S1 , S2 and S3, S4, respectively) of the first metrology unit 210.3 and the second metrology unit 210.4 are arranged substantially tangential to the circumferential direction of the mirror 106.6 and, hence, are inclined with res ect to each other.
  • the measurement planes P1 and MP2 defined by the sensing directions S1 , S2 and S3, S4, respectively
  • a variation of the orientation of the measurement planes MP1 , MP2 or MPS, respectively may be desired to improve or facilitate the observability of specific degrees of freedom which are of particular interest for the adjustment control loop.
  • a variation may cause a loss in capturing sensitivity as regards the point of interest (POI), e.g. due to a decrease in the distance of the measurement plane with regard to the point of interest (POI).
  • POI point of interest
  • the configuration shown in Figure 5 while allowing the implementation of simple, purely encoder based first and second metrology units 210.3 and 210.4, will have a lower sensitivity as regards the rotational degree of freedom about the x axis.
  • the advantages achieved may outweigh this drawback.
  • the embodiment shown in Figure 7 differs insofar from the first embodiment, as the first and second metrology component 1 12.2 and 112.4 are located on the rear side of the optical sub segment 11 1.1.
  • the fourth distance D4 between these first and second metrology components 1 12.2 and 1 12.4 and the third metrology component 112.6 may be further increased.
  • similar may be provided for the third metrology component 112.6 by placing the latter onto the front surface of the optical sub segment 111.1 (for example, integrating the third metrology component 1 12.6 into an area of the optical sub surface 111.2 optically unused in the exposure process).
  • the first and second metrology component 112.2 and 1 12.4 are located in the area of the rear side of the optical sub segment 111.1
  • the third metrology component 112.6 is placed in the area of the front surface of the optical sub segment 111.1.
  • the inverse arrangement may be provided, i.e. an arrangement where the first and second metrology component 112.2 and 112.4 are located in the area of the front side of the optical sub segment 111.1 , while the third metrology component 112.6 is placed in the area of the rear side of the optical sub segment 1 1 1.1.
  • optical elements are exclusively reflective elements
  • reflective, refractive or diffractive elements or any combinations thereof may be used for the optical elements of the optical element units.

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Abstract

L'invention concerne un agencement d'élément optique disposé sous forme d'un élément optique divisé comportant une pluralité de sous-éléments optiques. Un relâchement des contraintes d'espace de construction tout en maintenant la précision de mesure (et en fin de compte la précision de commande) peut être réalisé si trois unités de métrologie sont utilisées, les composants de métrologie respectifs associés aux sous-éléments optiques respectifs étant situés, tous deux, dans la zone du sous-élément définissant la circonférence extérieure de l'élément optique et au moins deux de ces composants de métrologie étant situés au moins près de leur distance maximale techniquement réalisable dans le plan circonférentiel et/ou dans une direction perpendiculaire à ce plan circonférentiel.
PCT/EP2014/059395 2013-05-10 2014-05-07 Agencement d'élément optique comportant un élément optique divisé en sous-éléments optiques WO2014180931A1 (fr)

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GB201309975A GB2513927A (en) 2013-05-10 2013-05-10 Optical element arrangement with an optical element split into optical sub-elements
GB1309975.9 2013-05-10

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120300183A1 (en) * 2011-05-26 2012-11-29 Carl Zeiss Smt Gmbh Optical arrangement in a microlithographic projection exposure apparatus

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090324174A1 (en) * 2004-02-25 2009-12-31 Carl Zeiss Smt Ag Device consisting of at least one optical element
WO2012059537A1 (fr) * 2010-11-05 2012-05-10 Carl Zeiss Smt Gmbh Objectif de projection d'un appareil d'exposition microlithographique
WO2013004278A1 (fr) * 2011-07-01 2013-01-10 Carl Zeiss Smt Gmbh Agencement d'imagerie optique avec composants supportés individuellement activement

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6225027B1 (en) * 1998-08-06 2001-05-01 Euv Llc Extreme-UV lithography system
US20090207511A1 (en) * 2005-05-09 2009-08-20 Carl Zeiss Smt Ag Assembly for adjusting an optical element
JP4883775B2 (ja) * 2006-08-11 2012-02-22 キヤノン株式会社 光学装置、露光装置及びデバイス製造方法
JP6093753B2 (ja) * 2011-03-23 2017-03-08 カール・ツァイス・エスエムティー・ゲーエムベーハー Ｅｕｖミラー機構、ｅｕｖミラー機構を備えた光学系、及びｅｕｖミラー機構を備えた光学系を操作する方法
DE102011076549A1 (de) * 2011-05-26 2012-11-29 Carl Zeiss Smt Gmbh Optische Anordnung in einer mikrolithographischen Projektionsbelichtungsanlage
DE102011077223B4 (de) * 2011-06-08 2013-08-14 Carl Zeiss Smt Gmbh Messsystem

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090324174A1 (en) * 2004-02-25 2009-12-31 Carl Zeiss Smt Ag Device consisting of at least one optical element
WO2012059537A1 (fr) * 2010-11-05 2012-05-10 Carl Zeiss Smt Gmbh Objectif de projection d'un appareil d'exposition microlithographique
WO2013004278A1 (fr) * 2011-07-01 2013-01-10 Carl Zeiss Smt Gmbh Agencement d'imagerie optique avec composants supportés individuellement activement

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120300183A1 (en) * 2011-05-26 2012-11-29 Carl Zeiss Smt Gmbh Optical arrangement in a microlithographic projection exposure apparatus
US9250417B2 (en) * 2011-05-26 2016-02-02 Carl Zeiss Smt Gmbh Optical arrangement in a microlithographic projection exposure apparatus

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GB201309975D0 (en) 2013-07-17

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