Optical arrangement and laser device

Abstract

The invention relates to an optical arrangement (16) for guiding a laser beam (20) along a beam path (18). The beam path (18) is divided into a first beam path portion (30) and a second beam path portion (32). The optical arrangement (16) has a deflection assembly (40), a frame device (38) for supporting the deflection assembly (40), and a fastening device (42). The deflection assembly (40) has a first mirror region (50) and a second mirror region (52), each for deflecting the laser beam (20), wherein the first beam path portion (30) is guided over the first mirror region (50) and the second beam path portion (32) is guided over the second mirror region (52). The fastening device (42) has at least two joints (58), the deflection assembly (40) being fastened to the frame device (38) by means of the at least two joints (58) of the fastening device (42).

Description

[0001] Optical arrangement and laser device

[0002] Description

[0003] The invention relates to an optical arrangement and a laser device.

[0004] Extreme ultraviolet radiation (EUV radiation) enables the precise and high-accuracy imaging of fine structures, which is why EUV radiation is frequently used in lithography, which can therefore be referred to as EUV lithography. Due to the advantage of precise and high-accuracy imaging of fine structures, EUV lithography is typically used for microchip production.

[0005] The EUV radiation for EUV lithography can be generated using a laser device. The laser device typically includes a laser beam generation assembly for generating a laser beam, a beam steering device, and a target chamber in which a target material is arranged.

[0006] The EUV radiation can be generated by directing and / or focusing the laser beam onto the target material using the beam steering device. In other words, the beam steering device can be configured to direct and / or focus the laser beam from the laser beam generation arrangement onto the target material. For this purpose, the beam steering device can comprise a plurality of optical components, in particular lenses and / or mirrors.

[0007] When the laser beam hits the target material, the material can be transformed into a plasma state by the laser beam, generating EUV radiation. In other words, the target material can emit EUV radiation when irradiated by the laser beam.

[0008] A vacuum condition is preferably set in the target chamber.

[0009] The target material can be a metal, for example, tin. The target material can be formed as droplets, for example, as tin droplets. Forming the target material as tin droplets can be particularly advantageous for generating EUV radiation due to its high yield of EUV radiation.

[0010] The laser beam generating arrangement may comprise a number of laser beam sources, for example, 1, 2, or 3. Each laser beam source may be configured to generate a laser beam. The laser beams from the laser beam sources may form the laser beam of the laser beam generating arrangement.

[0011] If the laser beam generating arrangement has two or more laser beam sources, the wavelengths of the laser beams of the laser beam sources may be equal in magnitude or may differ from each other.

[0012] For example, the laser beam generating arrangement may comprise a CO2 laser and a solid-state laser, wherein the CO2 laser provides a laser beam with a wavelength of 10.6 pm (micrometers) and the solid-state laser provides a laser beam with a wavelength in a range of 1 pm to 3 pm, preferably 1.01 to 1.08 pm.

[0013] The laser beam generation arrangement may comprise a number of laser amplifiers, for example, 1, 3, 4, or 6. Each laser amplifier may be configured to amplify the power of a laser beam from a laser beam source. For example, the laser beam generation device may comprise a CO2 laser amplifier for amplifying the power of the laser beam from the CO2 laser and / or a solid-state laser amplifier for amplifying the power of the laser beam from the solid-state laser.

[0014] For example, the laser beam of the CO2 laser can have an average power of over 5 kW (kilowatts), preferably over 10 kW, after passing through the CO2 laser amplifier.

[0015] Typically, a CO2 laser amplifier or a CO2 laser can have a frame device that accommodates, in particular supports, a plurality of components for the purpose of guiding a laser beam through the CO2 laser amplifier or CO2 laser. The components can include, for example, quartz tubes, mirrors, and / or lenses. A gaseous laser-active medium, in particular a gas mixture of carbon dioxide (CO2), nitrogen (N2), and helium (He), can be arranged in the quartz tubes. The gaseous laser-active medium can be brought into an energetic state by means of high-frequency electrical signals or high-frequency alternating current. The high-frequency electrical signals or the high-frequency alternating current can have a frequency in the megahertz or gigahertz range. In the energetic state, the laser-active medium can generate and / or amplify a laser beam.By generating and / or amplifying the laser beam, the laser-active medium can be converted from the energetic state to its original state.

[0016] The laser beam of the laser beam generation arrangement can be a pulsed laser beam. The pulsed laser beam can have pre-pulses and main pulses. Each main pulse can be preceded in time, particularly shortly before, by a pre-pulse. The pre-pulse can have a lower laser power than the main pulse. The pre-pulses and the main pulses can be generated using the same laser beam source or different laser beam sources.

[0017] It has been found to be particularly advantageous if the laser beam of the laser beam generating arrangement has a pre-pulse with a wavelength in a range from 1 pm to 3 pm, preferably 1.01 to 1.08 pm, and a main pulse with a wavelength in a range from 10 pm to 11 pm, in particular 10.6 pm.

[0018] The pre-pulse can prepare the target material for the impingement of the main pulse on the target material, so that when the main pulse impinges on the target material, the largest possible portion of the main pulse is converted into EUV radiation. In particular, the pre-pulse can be designed to influence the target material, for example, to heat, expand, vaporize, ionize, and / or convert the target material into the plasma state.

[0019] The main pulse can convert a major part of the target material influenced by the pre-pulse into the plasma state and thus generate EUV radiation.

[0020] The invention is based on the object of providing an optical arrangement and a laser device, each of which has improved properties, particularly enabling reliable operation under the influence of heat and / or being less sensitive to heat. The invention achieves this object by providing an optical arrangement having the features of claim 1 and a laser device having the features of claim 11. Advantageous embodiments and further developments of the invention are set out in the dependent claims.

[0021] An optical arrangement according to the invention is designed to guide a laser beam along a beam path, in particular for an EUV driver laser, in particular for a CO2 EUV driver laser. The beam path is divided into a first beam path section and a second beam path section. The optical arrangement has a deflection assembly, a frame device, and a fastening device. The deflection assembly has a first mirror region and a second mirror region. The first mirror region and the second mirror region are each designed to deflect the laser beam. The first beam path section is guided over the first mirror region, and the second beam path section is guided over the second mirror region. The frame device is designed to support the deflection assembly. The fastening device has at least two joints.The deflection assembly is fastened, in particular carried, to the frame device by means of the at least two joints of the fastening device.

[0022] Advantageously, the beam path has a U-turn and is divided by a center of the U-turn into the first beam path section and the second beam path section.

[0023] Advantageously, the deflection assembly can be mechanically decoupled from the frame device by means of the at least two joints in such a way that in the event of an inhomogeneous deformation of the frame device, for example in the form of a curvature, this is transmitted to the deflection assembly in a reduced manner or not at all. The inhomogeneous deformation can occur, for example, as a result of an inhomogeneous heat effect on the frame device. Therefore, by mechanical decoupling, a deflection of the laser beam by the first and second mirror region onto an undesired beam path can be reduced or completely prevented, which is why the optical arrangement enables more reliable operation when exposed to heat and is less sensitive to heat. In particular, this can achieve better beam stability. The heat effect can arise, for example, from the generation and / or amplification of the laser beam.The resulting heat can have an uneven or inhomogeneous effect on the frame assembly.

[0024] The laser beam may have a wavelength in a range from 10 pm to 11 pm, in particular 10.6 pm. The laser beam may have a power, in particular an average power, of at least 500 W, in particular of at least 1 kW or 10 kW.

[0025] The optical arrangement can comprise a first quartz tube, a second quartz tube, a third quartz tube, and a fourth quartz tube. The first quartz tube can be attached to the deflection assembly such that the laser beam of the first beam path section passes through the first quartz tube before being deflected by the first mirror region. The second quartz tube can be attached to the deflection assembly such that the laser beam of the first beam path section passes through the second quartz tube after being deflected by the first mirror region. The third quartz tube can be attached to the deflection assembly such that the laser beam of the second beam path section passes through the third quartz tube before being deflected by the second mirror region. The fourth quartz tube can be attached to the deflection assembly such that the laser beam of the second beam path section passes through the fourth quartz tube after being deflected by the second mirror region.

[0026] Each quartz tube of the optical assembly may be supported by the rack assembly.

[0027] The beam path can be a path or distance that the laser beam travels, or in particular is intended to travel, during its propagation.

[0028] The U-turn can be referred to as a fold or reversal. The U-turn can reverse the propagation direction of the laser beam. In particular, the propagation direction of the laser beam before passing through the U-turn and the propagation direction of the laser beam after passing through the U-turn can be opposite. The U-turn can be U-shaped.

[0029] The center of the U-turn can be a point where the laser beam has traveled halfway through the U-turn. In other words, when the laser beam has traveled halfway through the U-turn, the laser beam can be at or near the center of the U-turn.

[0030] Dividing the beam path through the center of the turn into a first beam path section and a second beam path section can be understood as meaning that the laser beam propagating along the beam path and not yet reaching the center of the turn propagates along the first beam path section, and the laser beam propagating along the beam path and having passed the center of the turn propagates along the second beam path section. In other words, the first beam path section can extend to the center of the turn, and the second beam path section can extend from the center of the turn.

[0031] The first beam path section may be a different beam path section from the second beam path section. In particular, the first beam path section and the second beam path section may not be identical. The first beam path section and the second beam path section may have a different course from one another.

[0032] The first beam path section and the second beam path section can be spaced apart from one another. The first beam path section and the second beam path section can be offset from one another. The first beam path section and the second beam path section can run parallel to one another. The first beam path section and the second beam path section can be arranged one above the other or next to one another.

[0033] The first beam path section can run in one beam path region, and the second beam path section can run in another beam path region. The beam path region and / or the another beam path region can be referred to as a beam path floor or beam path level. The beam path region and the another beam path region can be offset from one another. The beam path region and the another beam path region can be arranged one above the other or next to one another.

[0034] The deflection assembly may comprise a material block. The material block may be configured to attach the deflection assembly to the frame assembly by means of the at least two joints of the fastening device. The material block may comprise at least four receptacles for accommodating four quartz tubes.

[0035] The deflection assembly can form a corner of the optical assembly.

[0036] The optical arrangement can be cuboid-shaped. The deflection assembly can form a corner of the cuboid-shaped optical arrangement.

[0037] The optical arrangement may have an entrance for radiating the laser beam into the optical arrangement and an exit for radiating the laser beam out of the optical arrangement. The beam path may extend from the entrance to the exit. The entrance and / or the exit may be configured as an opening.

[0038] The first mirror region and the second mirror region can be formed by two mutually different regions of a single mirror of the deflection assembly. Alternatively, the deflection assembly can have a first mirror forming the first mirror region and a second mirror forming the second mirror region. The first mirror and the second mirror can be formed as separate components.

[0039] The deflection assembly may include at least one adjustable mirror holder for attaching and holding the single mirror to the material block. The deflection assembly may include two adjustable mirror holders for attaching and holding the first mirror and the second mirror to the material block.

[0040] The first mirror region and / or the second mirror region can each be designed to be highly reflective for the wavelength of the laser beam. Highly reflective can be understood as a reflection factor for the wavelength of the laser beam of at least 90%, preferably 95%, 98%, or 99%, or more. After passing through the first mirror region, the laser beam can continue its propagation along the first beam path section. After passing through the second mirror region, the laser beam can continue its propagation along the second beam path section.

[0041] The angle of incidence of the laser beam onto the first mirror region and / or the angle of incidence of the laser beam onto the second mirror region can be in the range of 40° to 60°, preferably 41° to 56°, particularly preferably 42° to 48°. In particular, the angle of incidence of the laser beam onto the first mirror region and / or the angle of incidence of the laser beam onto the second mirror region can be 45°.

[0042] The laser beam can be guided along the beam path by means of the first mirror region and the second mirror region. In other words, the first mirror region and / or the second mirror region can redirect the laser beam through reflection such that the laser beam propagates along the beam path.

[0043] Guiding the first beam path section over the first mirror region can be understood as meaning that the first beam path section encounters the first mirror region. Guiding the second beam path section over the second mirror region can be understood as meaning that the second beam path section encounters the second mirror region.

[0044] The mounting device can be designed as a frame. In particular, the mounting device can be designed as a frame for a CO2 laser amplifier or a CO2 laser.

[0045] The mounting device can be designed as an adapter plate. The mounting device can be formed as a single piece. The mounting device can be made of steel, aluminum, or stainless steel. The mounting device can have three joints. The deflection assembly can be attached to the frame using the three joints of the mounting device.

[0046] The deflection assembly can be firmly connected to the joints of the fastening device, and the frame device can be firmly connected to a fastening section of the fastening device. Alternatively, the deflection assembly can be firmly connected to the fastening section of the fastening device, and the frame device can be firmly connected to the joints of the fastening device.

[0047] The fastening device can be arranged between the deflection assembly and the frame device.

[0048] The at least two joints can be arranged such that the deflection assembly is mechanically coupled to the frame device. This can reduce or completely prevent the transmission of a second-order deformation, for example, in the form of a curvature, from the frame device to the deflection assembly.

[0049] The fastening device can be attached to the deflection assembly by means of a screw connection. The fastening device can be attached to the frame device by means of another screw connection.

[0050] By fastening the deflection assembly to the frame device by means of the at least two joints, it can be achieved that a curvature of the frame device as a result of heat acting on the frame device is not transferred to the deflection assembly in such a way that the first mirror region is tilted at an angle different from the second mirror region.

[0051] A further aspect of the optical arrangement can be that, upon introduction of a thermal load on one side of the frame, the frame can develop a curvature. By attaching the deflection assembly to the frame using the joints, the transfer of this curvature to the deflection assembly can be reduced or completely prevented. This can prevent the first mirror region from exhibiting a tilt as a result of the thermal load and the second mirror region from exhibiting a further tilt that differs from the tilt of the first mirror region.

[0052] In a further development of the optical arrangement, a thermal center of the fastening device is located in a center plane that runs between the first mirror region and the second mirror region. In other words, the center plane can separate the first mirror region and the second mirror region. In other words, the center plane can be located between the first beam path region and the second beam path region. The center plane cannot intersect the first mirror region and / or the second mirror region.

[0053] The thermal center can be a point or area of ​​the fastening device that does not change its position and / or location when the fastening device expands due to a uniformly distributed heat effect on the fastening device. In other words, the thermal center of the fastening device can be a point or area that does not experience any displacement as a result of the uniform heating or cooling of the fastening device. This can particularly apply if the fastening device is not connected to any other element and / or is considered separately. In other words, the thermal center can be a point or area of ​​the fastening device that does not change its position and / or location when the fastening device is viewed in isolation and when the fastening device expands as a result of uniform heating.

[0054] A center of gravity of the first mirror area and a center of gravity of the second mirror area can define a center of gravity line. In other words, the center of gravity line can connect the center of gravity of the first mirror area with the center of gravity of the second mirror area. The center plane can be oriented orthogonally to the center of gravity line.

[0055] A common center of gravity of the first mirror area and the second mirror area can be arranged in the center plane.

[0056] The center of the turn can be located in the center plane.

[0057] The deflection assembly can be attached to the fastening device by means of a fastening. The fastening can be formed by a plurality of screw connections. A fastening center point of the fastening can be arranged in the center plane. The fastening center point can be a point of symmetry of the individual fastenings.

[0058] In a further development of the optical arrangement, the deflection assembly is attached to the frame assembly by means of the fastening device with a statically determined connection. The deflection assembly can be attached to the fastening device at three fastening points. The at least two joints can each form a fastening point.

[0059] In a further development of the optical arrangement, the at least two joints are each designed as a flexure joint. Advantageously, this allows the mounting of the deflection assembly to be realized in a single component. Further advantageously, flexure joints can exhibit no friction and / or no hysteresis, making them particularly suitable for attaching the deflection assembly to the frame device. In particular, all joints of the fastening device can be designed as a flexure joint. Each flexure joint can have at least one web that acts as a spring element. A cross-sectional area of ​​all webs of a flexure joint can determine a mobility of the flexure joint. Each flexure joint can execute a movement by prestressing the web, in particular by bending the web.

[0060] In a further development of the optical arrangement, the at least two joints are each designed as a bivalent joint. This allows the transmission of a curvature of the frame device to the deflection assembly to be significantly reduced or completely prevented. Preferably, the fastening device can have three bivalent joints.

[0061] In a further development of the optical arrangement, the at least two joints each allow linear movement along a straight line. The straight lines of the at least two joints are each directed toward a thermal center or a center of gravity of the fastening device. This allows for particularly effective decoupling of the deflection assembly from the frame device. The center of gravity of the fastening device can be a center of mass.

[0062] In a further development of the optical arrangement, the at least two joints each have a limitation of the linear movement to a distance of a maximum of 1 mm, in particular 500 pm, 200 pm, or 100 pm. This can prevent the laser beam from being directed onto an undesired beam path by the first mirror region and / or the second mirror region. Each limitation can be designed as a stop of a joint. Furthermore, this can also reduce a force acting on the at least two joints, thus providing effective overload protection for the solid-state joints.

[0063] In a further development of the optical arrangement, the first mirror region and the second mirror region are independently adjustable. This allows the laser beam to be optimally guided or directed along the beam path by means of the first mirror region and the second mirror region. For example, this can compensate for manufacturing tolerances or production tolerances of the deflection assembly. The first mirror region and the second mirror region can each be attached to the material block of the deflection assembly with an adjustable mirror holder.

[0064] In a further development of the optical arrangement, the first mirror region and the second mirror region face the fastening device. This results in a particularly compact design of the optical arrangement. The first mirror region and / or the second mirror region can face the frame device.

[0065] A laser device according to the invention comprises a laser-active medium and an optical arrangement as described above. The laser-active medium is arranged such that the laser beam passes through the laser-active medium after passing through the first mirror region and before passing through the second mirror region.

[0066] A section of the beam path extending from the first mirror surface to the second mirror surface can be guided at least in sections through the laser-active medium.

[0067] The laser device can be designed as a CCh laser amplifier or a CO2 laser. In particular, as a CO2-EUV laser amplifier or a CO2-EUV driver laser.

[0068] The CO2 laser amplifier may have an input for irradiating the laser beam into the CO2 laser amplifier and an output for irradiating the laser beam from the CO2 laser amplifier. The beam path may extend from the input to the output.

[0069] The CO2 laser may have a resonator end mirror forming one end of the resonator of the CO2 laser and an output for emitting the laser beam from the CO2 laser. The output may be formed by a resonator output mirror. The beam path may extend from the resonator end mirror to the output.

[0070] The optical assembly can comprise four deflection assemblies as described above. Each deflection assembly can form a corner of the CO2 laser amplifier or CO2 laser.

[0071] The laser device and / or the laser beam can be configured to generate EUV radiation. An EUV lithography system according to the invention is configured to generate EUV radiation and direct it onto a semiconductor material and comprises a laser device with some or all of the features mentioned above for the laser device.

[0072] Further advantages and advantageous embodiments of the invention can be gathered from the figures, their description, and the claims. All features disclosed in the figures, their description, and the claims can be essential to the invention both individually and in any combination. They show:

[0073] Fig. 1 is a schematic oblique view of a laser device with a CO2 laser amplifier,

[0074] Fig. 2 is a schematic oblique view of a beam path of the CO2 laser amplifier of Fig. 1,

[0075] Fig. 3 is a schematic oblique view of a deflection assembly of the laser device of Fig. 1,

[0076] Fig. 4 is a schematic side view of the deflection assembly of Fig. 3,

[0077] Fig. 5 is a schematic oblique view of a fastening device of the laser device of Fig. 1,

[0078] Fig. 6 is a schematic side view of the fastening device of Fig. 5,

[0079] Fig. 7 is a schematic sectional view through a joint of the fastening device of Fig. 5,

[0080] Fig. 8 is a schematic representation of the deflection assembly of the laser device of Fig. 1 without heat exposure,

[0081] Fig. 9 is a schematic representation of the deflection assembly of Fig. 8 with heat exposure, and Fig. 10 is a schematic representation of another optical arrangement.

[0082] Fig. 1 shows a laser device 10. The laser device 10 has a CO2 laser amplifier 11 for amplifying a laser beam to generate EUV radiation. Fig. 1 only shows the CO2 laser amplifier 11 of the laser device 10. The CO2 laser amplifier 11 is cuboid-shaped.

[0083] The CO2 laser amplifier 11 has an input 12 for radiating the laser beam into the CO2 laser amplifier 11 and an output 14 for radiating the laser beam out of the CO2 laser amplifier 11.

[0084] The laser device 10, in particular the CO2 laser amplifier 11, has an optical arrangement 16 for guiding the laser beam along a beam path extending from the input 12 to the output 14.

[0085] Fig. 2 schematically illustrates the beam path 18 traveled by the laser beam 20 as it passes through the CO2 laser amplifier 11 of Fig. 1. In this case, the beam path 18 has a U-shaped turn 22 merely as an example. The turn 22 reverses the propagation direction of the laser beam 20. In other words, a propagation direction 24 of the laser beam 20 before passing through the turn 22 and a propagation direction 26 of the laser beam 20 after passing through the turn 22 are opposite to one another in this case.

[0086] In the present case, a center 28 of the U-turn 22 divides the beam path 18 into a first beam path section 30 and a second beam path section 32. The center 28 of the U-turn 22 is a point on the beam path 18 at which the laser beam 20 has passed halfway through the U-turn 22.

[0087] The first beam path section 30 extends from the entrance 12 to the center 28 of the turnaround 22. The second beam path section 32 extends from the center 28 of the turnaround 22 to the exit 14.

[0088] The first beam path section 30 extends in a beam path region 34, and the second beam path section 32 extends in a further beam path region 36. The beam path region 34 and the further beam path region 36 are arranged one above the other. Fig. 1 shows that the optical arrangement 16 has a frame device 38. The frame device 38 is designed as a frame. The frame device 38 supports the components for guiding the laser beam 20 along the beam path 18.

[0089] The optical assembly 16 has four deflection assemblies 40, each of which is attached to the frame assembly 38 by a fastening device 42. The deflection assemblies 40 are thus supported by the frame assembly 38. Each deflection assembly 40 forms a corner of the CO2 laser amplifier 11.

[0090] Each deflection assembly 40 has a material block 44. Two adjustable mirror holders 46 of the deflection assembly 40 are attached to each material block 44. Each mirror holder 46 is adjustable independently of the other mirror holders 46. Each mirror holder 46 holds a single mirror 48 of the deflection assembly 40. In total, each deflection assembly 40 has two mirrors 48. In total, the optical arrangement 16 has eight mirrors 48, see Fig. 2.

[0091] Each mirror 48 is highly reflective for a wavelength of the laser beam 20. In other words, the reflectance of each mirror 48 for the wavelength of the laser beam 20 is at least 98%.

[0092] The two mirrors 48 of each deflection assembly 40 form a first mirror region 50 of the deflection assembly 40 and a second mirror region 52 of the deflection assembly 40. In particular, one mirror 48 of a deflection assembly 40 forms the first mirror region 50 and the other mirror 48 of the deflection assembly 40 forms the second mirror region 52.

[0093] The laser beam 20 is guided along the beam path 18 by means of the first mirror region 50 and the second mirror region 52. By reflecting the laser beam 20 by the first mirror region 50 and the second mirror region 52, the laser beam 20 is deflected such that the laser beam 20 propagates along the beam path 18. As a result, the first mirror region 50 and the second mirror region 52 are each designed to deflect the laser beam 20. The first beam path section 30 is guided via the first mirror regions 50, and the second beam path section 32 is guided via the second mirror regions 52. The laser beam 20 continues its propagation along the first beam path section 30 after passing a first mirror region 50 and continues its propagation along the second beam path section 32 after passing a second mirror region 52.

[0094] An angle of incidence of the laser beam 20 on each first mirror area 50 and on each second mirror area 52 is 45°.

[0095] Each material block 44 has four receptacles 54 for accommodating quartz tubes 56 of the CO2 laser amplifier 11. A gaseous laser-active medium, in particular a gas mixture of carbon dioxide (CO2), nitrogen (N2), and helium (He), is arranged in the quartz tubes 56. The gaseous laser-active medium is brought into an energetic state by means of high-frequency alternating current, while the laser beam 20 passes through the laser-active medium.

[0096] Beam path 18 is guided through the laser-active medium. As laser beam 20 propagates along beam path 18, it passes through the laser-active medium and is amplified. After passing through exit 14, laser beam 20 can have an average power of over 10 kW.

[0097] Figs. 3 and 4 each show a deflection assembly 40 of the laser device 10 of Fig. 1. In particular, Fig. 4 shows that the fastening device 42 is arranged between the deflection assembly 40 and the frame device 38.

[0098] The deflection assembly 40 is attached to the frame device 38 by means of the fastening device 42. The deflection assembly 40 is attached to the frame device 38 such that the first mirror region 50 and the second mirror region 52 face the fastening device 42 and the frame device 38.

[0099] Figs. 5 and 6 each show a fastening device 42 of the laser device 10 of Fig. 1. The fastening device 42 is designed as a one-piece adapter plate. In the illustrated embodiment, the fastening device 42 is made of steel. The fastening device 42 has three joints 58 for fastening the deflection assembly 40 to the frame device 38. In particular, the deflection assembly 40 is fastened to the frame device 38 by means of the three joints 58 of the fastening device 42. The three joints fasten the deflection assembly 40 to the frame device 38 by means of a statically determined connection.

[0100] In particular, Fig. 6 shows that each joint 58 of the fastening device 42 is designed as a solid-state joint. Each joint 58 has a threaded bore 60 for establishing a screw connection between the fastening device 42 and the deflection assembly 40.

[0101] Each joint 58 has four webs 62 for supporting the threaded bore 60. The three threaded bores 60 are each connected to a remaining part of the fastening device 42 by means of the four webs 62.

[0102] Each web 62 acts as a spring element. Each flexure joint can move by prestressing the webs 62 and bending the webs.

[0103] The four webs 62 of each joint 58 are arranged parallel to each other. This allows the four webs 62 to allow linear movement of the threaded bore 60 along a straight line 64. This makes each joint 58 a two-way joint.

[0104] Each joint 58 has a limit stop 66 for linear movement of a maximum distance of 200 pm. Each limit stop 66 is designed as two opposing stops.

[0105] The three joints 58 are arranged such that the straight lines 64 intersect in a thermal center 68 of the fastening device 42.

[0106] The thermal center 68 is a point of the fastening device 42 which, in the event of a uniformly distributed heat effect in the fastening device 42, does not change its position and location due to thermal expansion caused by the heat effect.

[0107] Fig. 4 shows a center of gravity line 70 extending from a center of gravity 72 of the first mirror region 50 to a center of gravity 74 of the second mirror region 52 of a deflection assembly 40. A center plane 76 is aligned orthogonally to the center of gravity line 70. The thermal center 68 is located within the center plane 76.

[0108] The center plane 76 runs between the first mirror region 50 and the second mirror region 52. As a result, the first mirror region 50 and the second mirror region 52 are separated from each other by the center plane 76. The center plane 76 intersects neither the first mirror region 50 nor the second mirror region 52. A common center of gravity 78 of the first mirror region 50 and the second mirror region 52 can be located in the center plane 76.

[0109] Furthermore, Fig. 6 shows that the fastening device 42 has a number of countersunk holes 80 for fastening the fastening device 42 to the frame device 38. In the illustrated embodiment, the fastening device 42 has a total of six countersunk holes 80. In an alternative embodiment, the fastening device can have three, four, or eight countersunk holes.

[0110] By means of the countersunk holes 80, a screw connection is established between the fastening device 42 and the frame device 38.

[0111] Fig. 7 shows schematically a section through one of the joints 58 shown in Fig. 6 along its straight line 64. The fastening device 42 has a deflection side 82 facing the deflection assembly 40 and a frame side 84 facing the frame device 38. The deflection side 82 and the frame side 84 are opposite sides.

[0112] Each joint 58 of the fastening device 42 has a recess 86 on the frame side 84 to prevent contact between the joint 58 and the frame device 38 when the fastening device 42 is attached to the frame device 38. The recess 86 can have a depth 88 of at most 1 mm, in particular 500 μm, 200 μm, or 100 μm.

[0113] Each joint 58 of the fastening device 42 has a projection 90 on the deflection side 82 to prevent contact between a remaining area of ​​the fastening device 42 not having the joints 58 and the deflection assembly 40 when the deflection assembly 40 is attached to the fastening device 42. The projection 90 can have a height 92 of a maximum of 1 mm, in particular 500 μm, 200 μm, or 100 μm.

[0114] The recess 86 and the projection 90 ensure that the deflection assembly 40 can move by means of the joints 58 without the deflection assembly 40 rubbing against the fastening device 42 and without the fastening device 42 rubbing against the frame device 38. This allows the deflection assembly 40 to move unhindered.

[0115] In particular, by means of the fastening device 42 and its three joints 58 of the fastening device 42, it can be achieved that a curvature of the frame device 38 is transmitted to the deflection assembly 40 with a reduced effect or not at all. This is illustrated schematically in Figs. 8 to 10, wherein the same reference numerals are used for identical and functionally equivalent elements.

[0116] Fig. 8 shows the optical arrangement 16 without the occurrence of heat. This is the case, for example, when the CO2 laser amplifier 11 is not amplifying the laser beam 20.

[0117] Fig. 9 shows the optical assembly 16 with the heat applied. The heat applied occurs as a result of the amplification of the laser beam 20 by the CO2 laser amplifier 11. Due to the three joints 58, any curvature of the frame assembly 38 is not transferred to the deflection assembly 40, so that the first mirror region 50 and the second mirror region 52 have the same tilt angle 94.

[0118] Fig. 10 shows another optical arrangement with the heat effect and without the previously described mounting device. A curvature of the frame device 38 is transferred to the deflection assembly 40, so that a tilt angle 96 of the first mirror region 50 and a tilt angle 98 of the second mirror region 52 differ from each other.

Claims

Patent claims 1. An optical arrangement (16) for guiding a laser beam (20) along a beam path (18), in particular an optical arrangement (16) for an EUV driver laser, in particular for a CO2 EUV driver laser, wherein the beam path (18) is divided into a first beam path section (30) and a second beam path section (32), wherein the optical arrangement (16) comprises: a deflection assembly (40) having a first mirror region (50) and a second mirror region (52), each for deflecting the laser beam (20), wherein the first beam path section (30) is guided over the first mirror region (50) and the second beam path section (32) is guided over the second mirror region (52), a frame device (38) for supporting the deflection assembly (40), and a fastening device (42) having at least two joints (58),wherein the deflection assembly (40) is fastened to the frame device (38) by means of the at least two joints (58) of the fastening device (42).

2. Optical arrangement (16) according to claim 1, wherein the beam path (18) has a U-turn (22) and the beam path (18) is divided by a center (28) of the U-turn (22) into the first beam path section (30) and the second beam path section (32).

3. Optical arrangement (16) according to one of the preceding claims, wherein a thermal center (68) of the fastening device (42) is located in a center plane (76) which extends between the first mirror region (50) and the second mirror region (52).

4. Optical arrangement (16) according to one of the preceding claims, wherein the deflection assembly (40) is fastened to the frame device (38) by means of the fastening device (42) with a statically determined connection.

5. Optical arrangement (16) according to one of the preceding claims, wherein the at least two joints (58) are each designed as a solid-state joint.

6. Optical arrangement (16) according to one of the preceding claims, wherein the at least two joints (58) are each designed as a bivalent joint.

7. Optical arrangement (16) according to one of the preceding claims, wherein the at least two joints (58) each allow a linear movement along a straight line (64), wherein the straight lines (64) of the at least two joints (58) are each directed towards a thermal center (68) or a center of gravity of the fastening device (42).

8. Optical arrangement (16) according to claim 7, wherein the at least two joints (58) each have a limitation (66) of the linear movement to a distance with a value of at most 1 mm, in particular 500 pm.

9. Optical arrangement (16) according to one of the preceding claims, wherein the first mirror region (50) and the second mirror region (52) are adjustable independently of one another.

10. Optical arrangement (16) according to one of the preceding claims, wherein the first mirror region (50) and the second mirror region (52) face the fastening device (42).

11. Laser device (10), in particular EU driver laser, in particular CO2-EUV driver laser, comprising: a laser-active medium, and an optical arrangement (16) according to one of the preceding claims, wherein the laser-active medium is arranged such that the laser beam (20) passes through the laser-active medium after passing through the first mirror region (50) and before passing through the second mirror region (52).

12. EUV lithography system configured to generate EUV radiation and direct it onto a semiconductor material, comprising a laser device (10) according to claim

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