GB2468557A - Optical element module with imaging error correction and position adjustment - Google Patents
Optical element module with imaging error correction and position adjustment Download PDFInfo
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- GB2468557A GB2468557A GB1001888A GB201001888A GB2468557A GB 2468557 A GB2468557 A GB 2468557A GB 1001888 A GB1001888 A GB 1001888A GB 201001888 A GB201001888 A GB 201001888A GB 2468557 A GB2468557 A GB 2468557A
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- 238000003384 imaging method Methods 0.000 title description 18
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- 238000000034 method Methods 0.000 abstract description 32
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- 238000000576 coating method Methods 0.000 description 7
- 230000008021 deposition Effects 0.000 description 7
- 239000011248 coating agent Substances 0.000 description 6
- 238000001393 microlithography Methods 0.000 description 5
- 238000000206 photolithography Methods 0.000 description 5
- 239000004065 semiconductor Substances 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000005240 physical vapour deposition Methods 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
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- 229910052451 lead zirconate titanate Inorganic materials 0.000 description 2
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Classifications
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- 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
- G02B7/185—Mountings, adjusting means, or light-tight connections, for optical elements for prisms; for mirrors for mirrors with means for adjusting the shape of the mirror surface
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
- G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
- G02B26/0816—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements
- G02B26/0825—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements the reflecting element being a flexible sheet or membrane, e.g. for varying the focus
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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
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/08—Mirrors
- G02B5/0891—Ultraviolet [UV] mirrors
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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)
- Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
Abstract
There is provided a method of producing a reflective optical element module 2 for extreme ultra violet (EUV) applications, comprising, in a connecting step, connecting a first support structure 8, a reflective optical element 4 and an active structure 6 such that the first support structure supports the active structure and the active structure supports the reflective optical element. The reflective optical element has an optically effective surface portion and the active structure is adapted to adjustably introduce defined deformations into the reflective optical element. In a processing step, subsequent to the connecting step, an optically reflective surface on the optically reflective surface portion of the reflective optical element is then processed. A second support structure 10 is provided to support and enable adjustment of the position or orientation of the first support structure.
Description
OPTICAL ELEMENT MODULE WITH IMAGING ERROR AND POSITION CORRECTION
BACKGROUND OF THE INVENTION
The invention relates to a method of producing a reflective optical element module for extreme ultra violet applications and to corresponding reflective optical element modules used, for example, in exposure processes, in particular used in microlithography systems.
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 photolithography processes.
Typically, the optical systems used in the context of fabricating microelectronic devices such io as semiconductor 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. In extreme ultra violet (EUV) applications (working at wavelengths that typically range from nm to 5 nm, usually about 13 nm) the use of optical elements is normally limited to the use of reflective optical elements (like mirrors etc.). This is due to the high degree of absorption that light in the EUV range experiences in any solid or fluid medium. Thus, extreme ultra violet applications have to be performed in an evacuated environment in order to obtain sufficient light throughput through the optical system. The evacuation requirement raises the demands on the components of the optical system, for example, with regard to outgassing, which, in turn, raises the demands on the connections between the parts of the optical system or the optical element module.
In microlithography, or more specifically in photolithography, optical elements such as mirrors 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.
Due to the ongoing miniaturization of semiconductor devices there is a permanent need for enhanced resolution of the optical systems used for fabricating those semiconductor devices.
Requirements of higher resolution can be met by using working wavelengths in the extreme ultra violet wavelength range, for example, around 13 nm. But, this need for enhanced resolution obviously pushes the need for an increased imaging accuracy of the optical system.
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. 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 components of the optical system cooperating in the exposure process must be supported in a defined manner in order to provide and maintain a predetermined spatial relationship between said optical system components which, in turn, guarantees a high quality exposure process.
When optical elements are exposed to light having wavelengths from extreme ultra violet regimes, for example, around 13 nm, a considerable amount of heat is dissipated into the structure of the optical element. Of course, the same applies to exposure to other wavelength ranges, e.g. in the infrared spectrum etc. Heating, however, causes dimensional modification of the optical element due to thermal expansion leading to the actual geometry of the optical element deviating from the desired reference geometry. As a result, the imaging properties of the optical element can be altered making the optical element unsuitable for an application comprising, for example, selective exposure of a substrate coated with photoresist to extreme ultra violet light. To mitigate the heating effect, optical elements intended for use in extreme ultra violet applications can be made of a material having a coefficient of thermal expansion as low as possible. However, this countermeasure is not sufficient for some applications, for example, when exposure to the heat load has to be maintained over a rather long period of time or when a very high accuracy or very low deformations have to be respected. In order to deal with this alteration of imaging properties it has been proposed to actively deform the optical element during operation of the optical system, into which the optical element is integrated, in order to compensate for thermal expansion effects. Imaging property adjusting approaches are known, for example, from US 2003/0234918 Al (Watson) the entire disclosure of which is incorporated herein by reference.
Producing an optical element module comprising the integration of an optical element into a support structure, for example, a mount, may be a source of initial alterations of the geometry of the optical element. Alterations may stem, for example, from stresses introduced into the o optical element when it is contacted or connected with the support structure. These deviations from the desired reference or setpoint geometry of the optical element can either be accounted for by anticipating the geometry alteration and correcting the optical element accordingly before mounting (cf. US 2002/171922 Al; Shiraishi et al.) or by removing the optical element from the support structure, correcting it and returning it to the support structure (cf. US 2004/061868 Al; Chapman et al.). These solutions, however, are quite laborious.
When actuators are provided to adjustably introduce defined deformations into an optical element for the purpose of correction of the geometry of the optical element and when the optical element is movably and/or rotatably supported, care must be taken to avoid interaction of translational and/or rotational movements of the optical elements with deformations being imparted on the optical element, as such interaction may further alter the geometry of the optical element in an unpredictable, and hence hardly correctable, manner.
In US 2003/081722 Al (Kandaka et al.) a method is disclosed wherein an optical element is assembled into a housing of an optical system, for example, intended for microlithography, wherein the imaging properties of the mounted optical element are determined, and wherein io a correction is performed on the mounted optical element when the imaging properties do not comply with the desired reference imaging properties, for example, due to the geometry of the optical element deviating from a desired reference geometry. But, Kandaka et al. do not disclose that the support structure holding the optical element comprises means for adjustably introducing defined deformations into the optical element. As a result, geometry corrections of the optical element during operation of the optical system are not possible.
Such optical systems merely using active position control, but without active deformation control, may not be sufficient to eliminate or compensate some of the imaging errors that may already exist or arise during operation of the optical system. For example, wavefront aberrations resulting from uneven thermal loads acting on one or several of the optical elements of the optical system may not be satisfactorily compensated for by merely displacing one or several optical elements of the optical system.
SUMMARY OF THE INVENTION
It is thus an object of the invention to, at least some extent, overcome the above disadvantages and to suggest a method of producing a reflective optical element module, in particular for extreme ultra violet applications, which provides a reflective optical element module with good and long term reliable imaging properties of a compact optical system used, for example, in a microlithography or photolithography exposure process.
It is a further object of the invention to reduce the effort necessary for imaging property correction after mounting the reflective optical element on a support structure.
These objects are achieved according to a first aspect of the invention by a method of producing a reflective optical element module, in particular for extreme ultra violet applications, comprising, in a connecting step, connecting a first support structure, a reflective optical element and an active structure such that the first support structure supports the active structure and the active structure supports the reflective optical element. The reflective optical element has an optically effective surface portion and the active structure is adapted to adjustably introduce defined deformations into the reflective optical element. In a processing step, subsequent to the connecting step, an optically reflective surface on the optically reflective surface portion of the reflective optical element is then processed.
The optically effective surface on the optically effective surface portion of the reflective optical element is processed after the reflective optical element, the active structure and the first support structure have been connected, the latter preferably having a high rigidity.
Processing the optically reflective surface may be the final step in the production of the reflective optical element module. In this context it is to be mentioned that these components of the reflective optical element module as well as further components (such as e.g. a second support structure) may be connected to each other in an arbitrary order. The processing of the optically reflective surface, preferably, comprises at least one of the following processes such as ion beam figuring, polishing or coating, in particular by layer deposition, preferably physical vapour deposition or galvanic layer deposition.
In this way, the effort to apply imaging property correction, in particular geometry correction, to the reflective optical element is reduced, since a deviation of the geometry of the reflective optical element from a given setpoint geometry generated in the connecting step may be (at least largely) eliminated. As a result, the imaging accuracy of a reflective optical element module produced according to the invention are considerably increased and the requirements of high-end applications, such as extreme ultra violet applications in microlithography, in particular photolithography, which due to their nature have to be performed in an evacuated environment, are met.
The active structure is adapted to adjustably introduce defined deformations, in particular deformations in the nanometer range or even sub-nanometer range, and consequently allows for correction of the geometry of the reflective optical element and, thus, the imaging properties of the reflective optical element during operation of the optical system, in which the reflective optical element module with the reflective optical element is assembled. Hence, the demands on the finish of the optically effective surface can be lowered. Due to the serial arrangement of the active structure adapted to apply defined deformations and the second support structure adapted to adjust the position of the first support structure and, consequently, the position of the active structure and the optical element connected therewith, active positioning and active deforming can be performed separately, the former having virtually no influence on the latter and vice versa. In this way, undesired interaction of positioning and deforming can be kept low, or even prevented.
According to a second aspect of the invention a reflective optical element module for extreme ultra violet applications produced according to the method according to the first aspect of the invention is provided. The reflective optical element module comprises a reflective optical element, in particular a mirror, and a support structure supporting said reflective optical element. Said support structure comprises an active structure, a first support structure, and, preferably, a second support structure. Said active structure contacts said reflective optical element, in particular in a laminar manner, and is adapted to adjustably introduce defined deformations, in particular deformations of the order of nanometers, into said reflective optical element. Said first support structure supports said first holding structure, and said second support structure supports said first support structure and is adapted to adjust the position of said intermediate structure.
The reflective optical element module produced with the method according to the first aspect of the invention comprises a reflective optical element, which was not removed from the support system for geometry correction. Therefore, advantageously, the number of method steps of producing the reflective optical element module is reduced. Furthermore, the reflective optical element, prior to operation of the optical system into which it is integrated, was not removed, corrected and returned to the optical system, so that no traces of prior mounting, such as tiny deformations, for example, introduced by clamping devices, are evident from the body of the reflective optical element.
Further aspects and embodiments of the invention will become apparent from the dependent claims and the following description of preferred embodiments which refers to the appended figures. All combinations of the features disclosed, whether explicitly recited in the claims or not, are within the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic representation of a preferred embodiment of a reflective optical element module according to the invention; Figure 2 is a schematic representation of a preferred embodiment of a reflective optical element and an active structure being comprised in a reflective optical element module according to the invention shown in Figure 1; Figure 3 is a schematic sectional representation of another preferred embodiment of a reflective optical element, a active structure and a first support structure being comprised in a reflective optical element module according to the invention shown in Figure 1; Figure 3a is another schematic sectional representation of the active structure shown in Figure 3; and io Figures 4a-d are schematic representations of several variants of the method of producing a reflective optical element module for extreme ultra violet applications according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
In the following, a preferred embodiment of a reflective optical element module according to the invention will be described with reference to Figures 1 to 3a.
Figure 1 is a schematic and not-to-scale representation of a reflective optical element module 2 comprising a reflective optical element 4, such as a mirror, an active structure 6 being connected to the reflective optical element 4 and being adapted to adjustably introduce defined deformations, in particular deformations in the nanometer range or even sub-nanometer range, into the reflective optical element 4. In addition, a first support structure 8 is provided, which is connected with the active structure 6 and thereby supports the acttive structure 6. Finally, a second support structure 10 is provided, which is connected to the first support structure 8 and thereby supports the first support structure 8. The second support structure 10 is also adapted to adjust the position and/or orientation of the first support structure 8 (up to the order of several hundred microns) and thereby also provides positioning and/or orientation of the reflective optical element 4, which is indirectly connected to the second support structure 10 via the first support structure 8 and the active structure 6 in this exemplary embodiment.
Consequently, the active structure 6 and the second support structure 10 are arranged in the manner of serial kinematics in this example. The kinematically serial arrangement of the active structure 6 and the second support structure 10 has the advantage that an alteration in the position and/or orientation of the reflective optical element 4 may be obtained via the second support structure 10 without influencing the deformation of the reflective optical element 4 provided via the active structure 6. For example, it is possible to compensate thermal expansion related motion of the reflective optical element 4 without influencing the deformation of the reflective optical element 4 provided by the active structure 6.
Moreover, control of the deformation of the reflective optical element 4 and a control of the position and/or orientation of the reflective optical element 4 may be provided independently but contemporaneously, thereby allowing rapid reaction to altered boundary conditions within an exposure apparatus, into which the reflective optical element module 2 is integrated, e.g. during an exposure process, as well as providing a defined desired deformation and/or position alteration of the reflective optical element 4.
Connecting is, preferably, effected by one or more (in an arbitrary combination) of the following connecting techniques: adhesive bonding, brazing, welding, optical contacting or layer deposition. Layer deposition, in particular layer deposition using physical vapor deposition (PVD), is particularly suitable to connect the reflective optical element 4 with the active structure 6 in a coating process, for example, by depositing one or more layers of a reflective material onto the active structure 6.
Further specifying the schematic representation of the reflective optical element module shown in Figure 1, in an exemplary embodiment, the reflective optical element 4 may have an outer circumference and the active structure 6 may comprise a plurality of active elements 12, c.f. Figure 2, preferably being adapted to adjustably generate at least one of a deformation force and a deformation moment (in particular according to a piezoelectric, an electromagnetic, a pneumatic, a hydraulic, an electrostatic and/or a thermal working principle or combinations thereof) and to introduce it into the reflective optical element 4. To achieve generation of deformation forces and/or deformation moments the active elements 12 may comprise actuators, which apply one or more of the working principles mentioned before.
Examples of actuators are piezo-actuators, voice coil motors, fluidic actuators etc. An example becomes apparent from Figure 2 wherein a schematic selective view of the reflective optical element 4 and the active structure 6 (dashed contour) is shown. The active structure 6 may comprise a stipulated number of bellows as active elements 12 (of which only one is shown for reasons of clarity here). The respective bellows is connected to the reflective optical element 4 (and also to the first support structure 8, which is not shown) and can be actuated by means of a pressurized fluid (supplied through a feed line 14) such that it adjustably introduces defined deformations into the reflective optical element 4 in order to obtain a correction of the geometry of the reflective optical element 4 during operation of the optical system into which the reflective optical element 4 is integrated.
The active elements 12 mentioned above, such as the bellows from Figure 2, can be, in particular evenly, distributed at said outer circumference of the reflective optical element 4.
However, it will be appreciated that, with other embodiments of the invention, the active elements may also be (preferably evenly) distributed over the entire surface of the optical element. The active elements 12 contact the reflective optical element 4. It is further preferred that the active elements 12 are substantially rigidly connected to the reflective optical element 4.
Even further specifying the schematic representation of the reflective optical element module 2 shown in Figure 1, in an exemplary embodiment, the reflective optical element 4 may have an optically effective surface portion 16 and the reflective optical element 4 may have a backside 18 of the optically effective surface portion 16. The active structure 6 may comprise a plurality of active elements 12, again preferably being adapted to adjustably generate at least one of a deformation force and a deformation moment and introduce it into the reflective optical element 4. The active elements 12 can be, in particular evenly, distributed over at least a part of the backside 18 of the optically effective surface portion 16 and contact the reflective optical element 4. It is further preferred that the active elements 12 are substantially rigidly connected to the reflective optical element 4.
Another example is evident from Figure 3 wherein a schematic selective sectional view of the reflective optical element 4, the active structure 6 and the first support structure 8 is shown, the section being a plane running parallel to an optical axis 26 of the reflective optical element module 2. Therein, the active structure 6 consists of material comprising piezoelectrically active areas 20 (shaded) and said material is coated on the first support structure 8. The piezoelectrically active material may consist, for example, of lead-zirconate-titanate (PZT) or of silicon dioxide (Si02) or a combination thereof. The piezoelectrically active areas 20 in the material may be achieved, for example, by coating the material on the first support structure 8 and selectively polarizing certain areas of the material coated on the first support structure 8.
Additionally or alternatively, the active structure 6 may comprise at least one electrically conductive layer (e.g. a metallic layer) being adapted to function as one or more electrodes wherein the at least one electrically conductive layer is deposited and formed on the first support structure 8.
In Figure 3a a schematic sectional view through the active structure of Figure 3 in a plane perpendicular to the optical axis 26 is shown wherein the piezoelectrically active areas 20 and piezoelectrically inactive areas 28 can be seen. Optionally, it is possible to provide a structure of electrical contacts 30 (dashed lines; not shown for all piezoelectrically active areas 20 for clarity reasons) in the material layer in order to allow energizing of the piezoelectrically active areas 20. The structure of the electrical contacts 30 may be formed, for example, by depositing a conductor material, such as conductive metals, on the first io support structure 8 and subsequently forming the layout or structure of the electrical contacts 30. Then, the material intended to form the piezoelectrically active areas 20 can be coated on the first support structure 8 being already modified by the structure of electrical contacts 30.
It will be appreciated that, in many cases and, in particular, depending on the design of the piezoelectrically active areas 20, at least one further electrical contact 19, c.f. Figure 3, (forming a counter electrode) may be formed on the face of the active structure 6 opposite to the face receiving the electrical contacts 30. A single counter electrode 19 may be sufficient.
However, a plurality of counter electrodes (e.g. a structure of further electrical contacts 19 corresponding to the structure of the electrical contacts 30) may be provided as well.
Furthermore, the spatial arrangement of the electrical contacts 30 and the counter electrode(s) 19 (with respect to the piezoelectrically active areas 20) may of course also be chosen the other way round.
Now, again referring to Figure 1, the first support structure 8 may have an outer circumference and the second support structure 10 may comprise a plurality of second support elements 22, preferably being adapted to adjust the position of the first support structure 8, (according to a piezoelectric, electromagnetic, pneumatic, hydraulic, electrostatic, electrostrictive, magnetostrictive or thermal working principle or combinations thereof). The second support elements 22 can be, in particular evenly, distributed at said outer circumference of the first support structure 8 and contact the first support structure 8. In order to achieve position and/or orientation adjustment of the first support structure 8 the second support elements 22 may comprise actuators, which apply one or more of the In the exemplary embodiment of Figure 1 three holding element pairs 24 are provided, although another number of holding element pairs 24 is also possible. Each holding element -10-pair 24 is formed by two of the second support elements 22 in this case being arranged in the manner of a bipod. As is evident from Figure 1, three holding element pairs 24 support the first support structure 8 in the manner of a hexapod, and hence in a statically determinate way, being the preferred manner of connecting the reflective optical element module 2 to an optical system.
It will be appreciated that the second support elements 22 may be actively and/or passively adjustable elements allowing (active and/or passive) adjustment of the position and/or orientation of the first support structure 8. However, non-adjustable support elements may be used as well.
It will be appreciated that instead of bipods, any other suitable second support structure 10 may be provided to support the first support structure 8. Furthermore, it will be appreciated that, with other embodiments of the invention, position adjustment may be provided only in less than six degrees of freedom (DOE). For example, depending on the imaging error correction or compensation to be achieved, it may be sufficient that translational position adjustment parallel to the plane of main extension of the reflective optical element 4 (i.e. two DOF) and/or along the optical axis 26 of the reflective optical element 4 (i.e. three DOE or one DOF) is provided.
Even further specifying the schematic representation of the reflective optical element module 2 shown in Figures 1 to 3a, in an exemplary embodiment, at least one sensor (not shown), is preferably adapted to capture a value representative of a relative position and/or orientation between the reflective optical element 4 and a given reference. In addition or as an alternative, at least one sensor preferably being adapted to capture a motion value representative of a motion of the reflective optical element 4, is included in the reflective optical element module 2.
Furthermore, it will be appreciated that, in addition or as an alternative, at least one sensor may be adapted to capture a value representative of the surface figure of the reflective optical element 4 and/or at least one sensor and may be adapted to capture a value representative of a wavefront error of the wavefront of the optical system or, for example, representative of a wavefront error of the wavefront incident on the reflective optical element 4. Typically such sensors are not integrated within the reflective optical element module 2.
In further refined embodiments of the reflective optical element module 2 a capturing device and a control device (not shown) can be included in the reflective optical element module 2.
Said capturing device is, preferably, adapted to capture a value representative of a relative position and/or orientation between the reflective optical element 4 and a given reference and to transmit said captured value to said control device. The position control device is then adapted to control position and/or orientation adjustment of the first support structure 8 via the second support structure 10 as a function of said captured value. The reference may be any suitably well defined real component or virtual component (e.g. an optical plane etc.) of an optical system, in which the reflective optical element module 2 is assembled.
It will be appreciated that the capturing device may be of any suitable design providing the desired signal(s). For example, with certain embodiments of the invention, the active structure 6 and the second support structure 10 may form part of the capturing device, each providing a signal representative of the actual length of the respective active element 12 and second support element 22 and, thus, providing an information on the position and/or orientation of the reflective optical element 4 in relation to the optical system, in which the reflective optical element module 2 is assembled.
It will be further appreciated that the reflective optical element 4 may consist of a carrier element having a suitable reflective surface (e.g. a suitable reflective coating). However, in some variants of the present invention, the reflective optical element 4 may consist of one or a plurality of layers comprising at least one reflective layer deposited on the active structure 6. Furthermore, it will be appreciated that at least a part of the reflective optical element 4 may form the counter electrode(s) previously mentioned.
Figures 4a to 4d show flow diagrams of several variants of the method of producing a reflective optical element module 2 for extreme ultra violet applications. In Figure 4a, first, a reflective optical element 4 having an optically effective surface portion 16, an active structure 6, a first support structure 8, and a second support structure 10 are provided (box 32). Then, said second support structure 10 is connected to said first support structure 8, so that said second support structure 10 supports said first support structure 8 (box 34). Then, said first support structure 8 is connected to said active structure 6, so that said first support structure 8 supports said active structure 6 (box 36). Then, said active structure 6 is connected to said reflective optical element 4, so that said active structure 6 supports said reflective optical element 4 (box 38). Finally, in this example, an optically reflective surface on said optically reflective surface portion 16 of said reflective optical element 4 is processed, e.g. generated and/or worked (box 40).
In Figure 4b the order of method steps is changed in that connecting the reflective optical element 4 with the active structure 6 (box 38)is performed after providing the reflective optical element 4, the active structure 6, the first support structure 8 and the second support -12-structure 10 (box 32). Then, the second support structure 10 is connected to the first support structure 8 (box 34) and the first support structure 8 is connected to the active structure (box 36). Again, finally, an optically reflective surface on said optically reflective surface portion 16 of said reflective optical element 4 is processed (e.g. generated and/or worked; box 40). By processing the optically reflective surface after connecting the reflective optical element 4 to the active structure 6, any geometry alterations, and consequently imaging property alterations, of the reflective optical element 4, which are caused by the connecting step, can be reduced, or even avoided.
In the variants shown in Figures 4a and 4b processing said optically reflective surface (box 40) is the final step in the production of said reflective optical element module 2.
Other variants of the method according to the invention with differing order of the method steps are shown in Figures 4c and 4d, wherein connecting the reflective optical element 4 with the active structure 6 (box 38) and processing an optically effective surface (box 40) are performed subsequently, whereas the order of the other method steps (boxes 34 and 36) may be chosen in an arbitrary manner. In particular, the step of generating and/or working an optically effective surface does not finish the production of the reflective optical element module 2 in these cases. Furthermore, in a variant of Figure 4d steps 38 and 36 may be exchanged.
In a further variant of the method according to the invention said active structure 6 may comprise a material having piezoelectrically active areas 20. The first support structure 8 may be coated with said material. The piezoelectrically active areas 20 may, then, be formed by selectively polarizing certain areas of said material.
In another variant of the method according to the invention said active structure 6 may consist of at least one electrically conductive (e.g. metallic) layer being adapted to function as one or more electrodes wherein said at least one electrically conductive layer is deposited, and -as the case may be -formed, on said first support structure 8.
In a further variant of the method according to the invention said processing said optically reflective surface comprises at least one of the following techniques or arbitrary combinations thereof: ion beam forming, polishing, coating, in particular by layer deposition, preferably layer deposition by physical vapour deposition, etc. It will be appreciated that, in some embodiments of the present invention, the reflective optical element 4 itself may be formed by a simple reflective coating of the active structure 6.
-13 -In this case, eventually, the reflective coating forming the reflective optical element 4 may also form or integrate, respectively, the electrode 19 used in controlling the active structure.
It will be further appreciated that, with certain embodiments of the invention, the active structure 6 may not only be adapted to control deformation of the reflective optical element 4 but also to control a position and/or an orientation of the reflective optical element 4.in these cases the adjustable support elements 22 may even be omitted (and, eventually, the first support structure 8 and the second support structure 24 may be integrally formed).
It will be appreciated that the present invention may be used in a particularly beneficial way for applications using light in the EUV range. Moreover, the present invention is particularly beneficial in the context of optical imaging processes used for manufacturing microelectronic devices. However, the present invention may also be used in the context of any other optical imaging process, in particular, optical imaging processes using light at wavelengths different from the ones of the EUV range.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1001888A GB2468557A (en) | 2010-02-05 | 2010-02-05 | Optical element module with imaging error correction and position adjustment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1001888A GB2468557A (en) | 2010-02-05 | 2010-02-05 | Optical element module with imaging error correction and position adjustment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB201001888D0 GB201001888D0 (en) | 2010-03-24 |
| GB2468557A true GB2468557A (en) | 2010-09-15 |
Family
ID=42082523
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1001888A Withdrawn GB2468557A (en) | 2010-02-05 | 2010-02-05 | Optical element module with imaging error correction and position adjustment |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2468557A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102021200113A1 (en) | 2021-01-08 | 2022-07-14 | Carl Zeiss Smt Gmbh | Optical device, method for controlling an optical device, computer program product and lithography system |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20070286035A1 (en) * | 2006-05-23 | 2007-12-13 | Canon Kabushiki Kaisha | Reflecting apparatus |
| US7380950B1 (en) * | 2005-02-15 | 2008-06-03 | Lockheed Martin Corporation | Hybrid high-bandwidth deformable fast steering mirror |
-
2010
- 2010-02-05 GB GB1001888A patent/GB2468557A/en not_active Withdrawn
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7380950B1 (en) * | 2005-02-15 | 2008-06-03 | Lockheed Martin Corporation | Hybrid high-bandwidth deformable fast steering mirror |
| US20070286035A1 (en) * | 2006-05-23 | 2007-12-13 | Canon Kabushiki Kaisha | Reflecting apparatus |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102021200113A1 (en) | 2021-01-08 | 2022-07-14 | Carl Zeiss Smt Gmbh | Optical device, method for controlling an optical device, computer program product and lithography system |
| WO2022148698A1 (en) | 2021-01-08 | 2022-07-14 | Carl Zeiss Smt Gmbh | Optical device and method for controlling an optical device |
Also Published As
| Publication number | Publication date |
|---|---|
| GB201001888D0 (en) | 2010-03-24 |
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