DE102020200693A1 - OPTICAL SYSTEM AND LITHOGRAPH SYSTEM - Google Patents

Abstract

An optical system (200) for a lithography system (100A, 100B), comprising an optical element (202), a force actuator (212) which is designed to apply a force (F) to the optical element (202) in order to adjust it , and a damping device (300) for damping vibration modes of the optical element (202), wherein the damping device (300) is arranged between the optical element (202) and the force actuator (212) in such a way that a force path (FP) of the force ( F) takes its way over the damping device (300).

Description

The present invention relates to an optical system and a lithography system with such an optical system.

Microlithography is used to manufacture microstructured components, such as integrated circuits. The microlithography process is carried out with a lithography system which has an illumination system and a projection system. The image of a mask (reticle) illuminated by means of the lighting system is projected by means of the projection system onto a substrate, for example a silicon wafer, coated with a light-sensitive layer (photoresist) and arranged in the image plane of the projection system, in order to create the mask structure on the light-sensitive coating of the substrate transferred to.

Driven by the striving for ever smaller structures in the manufacture of integrated circuits, EUV lithography systems (English: extreme ultraviolet, EUV) are currently being developed which emit light with a wavelength in the range from 0.1 nm to 30 nm, in particular 13.5 nm , use. In such EUV lithography systems, because of the high absorption of most materials of light of this wavelength, reflective optics, that is to say mirrors, must be used instead of - as before - refractive optics, that is, lenses.

These mirrors can be attached to a support frame and designed to be at least partially manipulable in order to enable a movement of the respective mirror, for example in six degrees of freedom, whereby changes in the optical properties that occur during operation of the lithography system, for example as a result of thermal influences, can be compensated.

In the operation of EUV systems, dynamic aspects, for example in the suppression of forces on the respective mirror or in the consideration and suppression of vibrations excited in the system, are of increasing importance. One of the factors contributing to this is the fact that the natural frequencies of the mechanical structures keep shifting towards smaller frequencies for the growing dimensions of the mirrors. As a result, occurring vibrations lead to growing problems with regard to the performance of the system and also to the effect that an active position control of the mirrors can no longer be operated in a stable manner or only with poor control quality.

The DE 10 2011 007 917 A1 discloses how a mirror in an EUV projection system can be kept still with respect to a reference by actively regulating the position. In order to keep the structure of the position controller simple and robust, the mirror is viewed approximately as a rigid body with respect to the position controller, which is to be positioned in six degrees of freedom. Since the mirror is not infinitely rigid, the transfer function of the open control loop leads to resonance peaks in the natural frequencies of the mirror. These can lead to instability of the control loop. The accuracy of the positioning of the mirror deteriorates. It also describes how disruptive resonances can be filtered out with the help of an (electrical or mechanical) filter.

Corresponding vibration modes can only be filtered out if there is a sufficient distance between the frequency of the position controller bandwidth and the first natural frequency of the mirror. However, this distance is no longer given for many mirrors in new EUV designs, since the mirrors are getting bigger and bigger and the natural frequencies are getting smaller and smaller.

Against this background, it is an object of the present invention to provide an improved optical system for a lithography system.

Accordingly, an optical system for a lithography system is proposed. The optical system comprises an optical element, a force actuator which is configured to apply a force to the optical element for adjusting the optical element, and a damping device for damping oscillation modes of the optical element, the damping device being arranged in this way between the optical element and the force actuator is that a force path of the force takes its way through the damping device.

Because the damping device is arranged between the force actuator and the optical element, the dynamics of the optical element can be positively influenced, since resonances can be damped which could leave a control loop for regulating the position of the optical element unstable.

The optical element is in particular a mirror, preferably an EUV mirror. The optical element has an optically effective surface, in particular a mirror surface. A rear side of the optical element is provided facing away from the optically active surface. The damping device is preferably coupled to the rear side. A “force actuator” is to be understood as an adjusting element that, in contrast to a travel actuator, does not specify a fixed path, but rather a force. An example of a travel actuator is a piezo element. The force actuator can also be referred to as a force setting element or force actuator. For example, the force actuator can be a so-called Lorenz actuator.

The damping device has, in particular, viscoelastic properties. “Viscoelasticity” is to be understood as a partially elastic, partially viscous material behavior. Viscoelastic materials combine the characteristics of solids and liquids. For example, the damping device can be implemented with the aid of an elastomer such as rubber. However, the damping device can also be implemented with the aid of a fluid. In this case, the damping device can be pneumatic or hydraulic. In physics, a “vibration mode” or eigenform, natural vibration form or partial vibration is the description of certain temporally stationary properties of a wave. The wave is described as the sum of different modes.

The fact that the damping device is arranged “between” the optical element and the force actuator means in particular that the damping device connects the optical element to the force actuator. The “force path” is to be understood as a path that the force exerted by the force actuator takes through the optical system. In the present case, the force path runs from the force actuator to the damping device and from the damping device to the optical element.

The optical element or its optically effective surface preferably has six degrees of freedom, namely three translational degrees of freedom each along a first spatial direction or x-direction, a second spatial direction or y-direction and a third spatial direction or z-direction as well as three rotational degrees of freedom each around the x -Direction, the y-direction and the z-direction. That is, the position and the orientation of the optical element or the optically effective surface can be determined or described with the aid of the six degrees of freedom. Several force actuators are therefore provided in order to move the optical element in all six degrees of freedom. For this purpose, two force actuators act on one point, in particular on a socket, of the optical element. Two translational directions are therefore possible per point or per socket. The rotary movement takes place via a respective lever arm. The socket is a mirror socket or can be referred to as a mirror socket.

The “position” of the optical element or the optically active surface is to be understood in particular as its or its coordinates or the coordinates of a measuring point provided on the optical element with respect to the x direction, the y direction and the z direction. The “orientation” of the optical element or the optically effective surface is to be understood in particular as its or its tilting with respect to the three spatial directions. This means that the optical element or the optically effective surface can be tilted about the x direction, the y direction and / or the z direction. This results in the six degrees of freedom for the position and / or orientation of the optical element or the optically effective surface.

A “position” of the optical element or the optically active surface includes both its or its position and its or its orientation. “Adjustment” is accordingly to be understood as meaning that both the orientation and the position of the optical element can preferably be changed in order to keep the optical element or the optically effective surface in a desired position. Six force actuators are provided for adjusting the optical element. The optical system further comprises a position sensor for detecting an actual position of the optical element and a control unit which controls the force actuator or actuators on the basis of sensor signals from the position sensor. The force actuators, the position sensor or sensors and the control unit form a control loop of the optical system. With the aid of the control loop, the optical element is held still with respect to a reference.

According to one embodiment, the force actuator has a magnetic element and a coil element for generating the force, the magnetic element being coupled to the optical element with the aid of an actuating element.

Several, for example four, coil elements can be assigned to each force actuator. The magnet element can be deflected with the aid of energizing the coil element or the coil elements. The actuating element is preferably rod-shaped. The actuating element is preferably connected with the aid of a joint, in particular a ball joint or a solid body joint, to a socket as mentioned above, which in turn is firmly connected, in particular glued, to the optical element.

According to a further embodiment, the damping device is arranged between the magnetic element and the actuating element.

For example, the damping device connects the magnetic element to the actuating element. The damping device can, however, also be arranged between the actuating element and the optical element.

According to a further embodiment, the force actuator has a coupling element which is arranged within the magnetic element and which is coupled to the actuating element, the damping device being arranged between the magnetic element and the coupling element.

The magnetic element preferably comprises a cylindrical cavity in which the likewise cylindrical coupling element is received. The coupling element is preferably coupled to the actuating element with the aid of a further joint, in particular a ball joint or a solid body joint.

According to a further embodiment, the optical system further comprises a socket which is fixedly connected to the optical element, the damping device being arranged between the socket and the actuating element.

The socket is in particular a mirror socket as mentioned above. The socket is preferably glued to the optical element. In particular, the socket is glued to the rear of the optical element.

According to a further embodiment, the damping device has two damping elements, in particular O-rings.

As a result, the damping device can be manufactured particularly inexpensively. The damping elements can be constructed identically or differently. For example, the damping elements can have different diameters.

According to a further embodiment, the damping elements have different dimensions.

In the event that the damping elements are O-rings, these have, for example, different inside diameters and / or cord thicknesses.

According to a further embodiment, the damping device is disk-shaped.

The damping device can, however, also be hollow-cylindrical, conical or pyramidal.

According to a further embodiment, the bushing is ring-shaped, with a connecting element being received in the bushing, which is coupled to the actuating element, and wherein the damping device is arranged between the bushing and the connecting element.

In this case, the damping device is preferably in the shape of a hollow cylinder. The connecting element is preferably disk-shaped. The force is applied to the connecting element with the aid of the actuating element. The connecting element can be coupled to the actuating element with the aid of a joint as explained above.

According to a further embodiment, the damping device is vulcanized onto the socket and onto the actuating element.

This means that there is no need for an additional adhesive. This means there is no risk of harmful outgassing of the adhesive.

According to a further embodiment, the damping device is hollow-cylindrical.

For example, the damping device can be a hose made from an elastomer.

According to a further embodiment, two force actuators are provided which are coupled to a common actuating element.

In this case, only one actuating element is provided per socket. For example, the magnetic elements of the two force actuators are screwed onto the actuating element.

According to a further embodiment, the force actuators are positioned perpendicular to one another.

This means in particular that the central axes of the magnetic elements of the force actuators intersect.

According to a further embodiment, the damping device has a spring element and a damping cylinder.

The spring element and the damping cylinder can be realized together with the help of an elastomeric material. The spring element can - but does not have to - be provided as an additional metallic component which forms an additional connection between the force actuator and the optical element. The spring element is then installed parallel to the elastomer. This allows the ratio of stiffness to damping be influenced, since the stiffness of the spring element has to be added to the stiffness of the elastomer, but the spring element does not contribute to the damping. However, this combination can also be used as a design parameter, for example in the event that an elastomer is selected for outgassing reasons which actually provides too much damping

Furthermore, a lithography system with at least one such optical system is proposed.

The optical system can in particular be a projection system or a beam shaping and lighting system of the lithography system. The optical system can also be part of such a projection system or such a beam shaping and lighting system. The lithography system can comprise several optical systems. The lithography system can be an EUV lithography system or a DUV lithography system. EUV stands for “Extreme Ultraviolet” and designates a wavelength of the work light between 0.1 nm and 30 nm. DUV stands for “Deep Ultraviolet” and designates a wavelength of the work light between 30 nm and 250 nm.

In the present case, “a” is not necessarily to be understood as restricting to exactly one element. Rather, several elements, such as two, three or more, can also be provided. Any other counting word used here is also not to be understood to mean that there is a restriction to precisely the specified number of elements. Rather, numerical deviations upwards and downwards are possible, unless otherwise stated.

The embodiments and features described for the optical system apply correspondingly to the proposed lithography system and vice versa.

Further possible implementations of the invention also include combinations, not explicitly mentioned, of features or embodiments described above or below with regard to the exemplary embodiments. The person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.

• 1A zeigt eine schematische Ansicht einer Ausführungsform einer EUV-Lithographieanlage;
• 1B zeigt eine schematische Ansicht einer Ausführungsform einer DUV-Lithographieanlage;
• 2 zeigt eine schematische Ansicht einer Ausführungsform eines optischen Systems für die Lithographieanlage gemäß 1A oder 1B;
• 3 zeigt eine schematische Schnittansicht einer weiteren Ausführungsform eines optischen Systems für die Lithographieanlage gemäß 1A oder 1B;
• 4 zeigt eine schematische perspektivische Ansicht einer weiteren Ausführungsform eines optischen Systems für die Lithographieanlage gemäß 1A oder 1B;
• 5 zeigt eine schematische Schnittansicht des optischen Systems gemäß 4;
• 6 zeigt eine schematische Schnittansicht einer weiteren Ausführungsform eines optischen Systems für die Lithographieanlage gemäß 1A oder 1B;
• 7 zeigt eine schematische Schnittansicht einer weiteren Ausführungsform eines optischen Systems für die Lithographieanlage gemäß 1A oder 1B; und
• 8 zeigt eine schematische Schnittansicht einer weiteren Ausführungsform eines optischen Systems für die Lithographieanlage gemäß 1A oder 1B.

Further advantageous configurations and aspects of the invention are the subject matter of the subclaims and the exemplary embodiments of the invention described below. In the following, the invention is explained in more detail on the basis of preferred embodiments with reference to the attached figures.

• 1A shows a schematic view of an embodiment of an EUV lithography system;
• 1B shows a schematic view of an embodiment of a DUV lithography system;
• 2 FIG. 11 shows a schematic view of an embodiment of an optical system for the lithography system according to FIG 1A or 1B ;
• 3 shows a schematic sectional view of a further embodiment of an optical system for the lithography system according to FIG 1A or 1B ;
• 4th FIG. 11 shows a schematic perspective view of a further embodiment of an optical system for the lithography system according to FIG 1A or 1B ;
• 5 FIG. 13 shows a schematic sectional view of the optical system according to FIG 4th ;
• 6th shows a schematic sectional view of a further embodiment of an optical system for the lithography system according to FIG 1A or 1B ;
• 7th shows a schematic sectional view of a further embodiment of an optical system for the lithography system according to FIG 1A or 1B ; and
• 8th shows a schematic sectional view of a further embodiment of an optical system for the lithography system according to FIG 1A or 1B .

In the figures, elements that are the same or have the same function have been provided with the same reference symbols, unless otherwise indicated. It should also be noted that the representations in the figures are not necessarily to scale.

1A shows a schematic view of an EUV lithography system 100A , which is a beam shaping and lighting system 102 and a projection system 104 includes. EUV stands for "extreme ultraviolet" (English: extreme ultraviolet, EUV) and designates a wavelength of work light between 0.1 nm and 30 nm. The beam shaping and lighting system 102 and the projection system 104 are each provided in a vacuum housing, not shown, with each vacuum housing being evacuated with the aid of an evacuation device, not shown. The vacuum housings are surrounded by a machine room, not shown, in which drive devices are provided for mechanically moving or adjusting optical elements are. Furthermore, electrical controls and the like can also be provided in this machine room.

The EUV lithography system 100A has an EUV light source 106A on. As an EUV light source 106A For example, a plasma source (or a synchrotron) can be provided, which radiation 108A in the EUV range (extreme ultraviolet range), for example in the wavelength range from 5 nm to 20 nm. In the beam shaping and lighting system 102 becomes the EUV radiation 108A bundled and the desired operating wavelength from the EUV radiation 108A filtered out. The one from the EUV light source 106A generated EUV radiation 108A has a relatively low transmissivity through air, which is why the beam guidance spaces in the beam shaping and lighting system 102 and in the projection system 104 are evacuated.

This in 1A beam shaping and lighting system shown 102 has five mirrors 110 , 112 , 114 , 116 , 118 on. After going through the beam shaping and lighting system 102 becomes the EUV radiation 108A on a photo mask (Engl .: reticle) 120 directed. The photo mask 120 is also designed as a reflective optical element and can be used outside of the systems 102 , 104 be arranged. The EUV radiation can continue 108A by means of a mirror 122 on the photo mask 120 be steered. The photo mask 120 has a structure which by means of the projection system 104 scaled down to a wafer 124 or the like is mapped.

The projection system 104 (also known as a projection lens) has six mirrors M1 to M6 for imaging the photomask 120 on the wafer 124 on. Individual mirrors can be used M1 to M6 of the projection system 104 symmetrical about an optical axis 126 of the projection system 104 be arranged. It should be noted that the number of mirrors M1 to M6 the EUV lithography system 100A is not limited to the number shown. There can also be more or less mirrors M1 to M6 be provided. Furthermore are the mirrors M1 to M6 usually curved on their front side to shape the beam.

1B shows a schematic view of a DUV lithography system 100B , which is a beam shaping and lighting system 102 and a projection system 104 includes. DUV stands for "deep ultraviolet" (English: deep ultraviolet, DUV) and describes a wavelength of work light between 30 nm and 250 nm. The beam shaping and lighting system 102 and the projection system 104 can - as already with reference to 1A described - be arranged in a vacuum housing and / or surrounded by a machine room with appropriate drive devices.

The DUV lithography system 100B has a DUV light source 106B on. As a DUV light source 106B For example, an ArF excimer laser can be provided, which radiation 108B emitted in the DUV range at 193 nm, for example.

This in 1B beam shaping and lighting system shown 102 directs the DUV radiation 108B on a photo mask 120 . The photo mask 120 is designed as a transmissive optical element and can be used outside of the systems 102 , 104 be arranged. The photo mask 120 has a structure which by means of the projection system 104 scaled down to a wafer 124 or the like is mapped.

The projection system 104 has multiple lenses 128 and / or mirror 130 for imaging the photomask 120 on the wafer 124 on. Individual lenses 128 and / or mirror 130 of the projection system 104 symmetrical about an optical axis 126 of the projection system 104 be arranged. It should be noted that the number of lenses 128 and mirror 130 the DUV lithography system 100B is not limited to the number shown. There can also be more or fewer lenses 128 and / or mirror 130 be provided. Furthermore are the mirrors 130 usually curved on their front side to shape the beam.

An air gap between the last lens 128 and the wafer 124 can through a liquid medium 132 be replaced, which has a refractive index> 1. The liquid medium 132 can for example be ultrapure water. Such a structure is also referred to as immersion lithography and has an increased photolithographic resolution. The medium 132 can also be referred to as immersion liquid.

2 Figure 11 shows a schematic view of an embodiment of an optical system 200 . The optical system 200 is part of an EUV lithography system as explained above 100A or DUV lithography system 100B . The optical system 200 can in particular a projection system as explained above 104 or a beam shaping and lighting system 102 or part of such a projection system 104 or such a beam shaping and lighting system 102 be.

The optical system 200 includes an optical element 202 . The optical element 202 for example one of the mirrors 110 , 112 , 114 , 116 , 118 , 130 , M1 to M6 and / or one of the lenses 128 be. The optical element 202 is not an infinitely rigid body, but represents a system which May have vibration modes. That is why the optical element 202 in the 2 represented as a system that has a first mass 204 and a second mass 206 having, with the help of a spring element 208 are connected to each other. The optical element 202 can be an optically effective surface 210 , for example a mirror surface.

Furthermore, the optical system 200 a force actuator 212 on, with the help of which to adjust the optical element 202 a force F. on the optical element 202 can be exercised. The force actuator 212 can also be referred to as a force actuator or force actuator. In contrast to a path actuator, which specifies a path, the force actuator gives 212 not a way, but the force F. in front.

The force actuator 212 includes in the very schematic representation according to 2 a spring element 214 and a magnetic element 216 that with the help of the spring element 214 with a fixed world 218 is coupled. The solid world 218 can for example be a support frame (force frame) of the lithography system 100A , 100B be. An actuator 220 , for example a rod-shaped plunger, is provided to the force F. from the force actuator 212 on the optical element 202 transferred to. The magnetic element 216 can be a permanent magnet.

The optical element 202 or its optically effective area 210 preferably has six degrees of freedom, namely three translational degrees of freedom each along a first spatial direction or x-direction x, a second spatial direction or y-direction y and a third spatial direction or z-direction z and three rotational degrees of freedom each around the x-direction x, the y-direction y and the z-direction z. That is, the position and the orientation of the optical element 202 or the optically effective area 210 can be determined or described using the six degrees of freedom. There are therefore several force actuators 212 provided to the optical element 202 to move in all six degrees of freedom.

Under the "position" of the optical element 202 or the optically effective area 210 are in particular its or their coordinates or the coordinates of one on the optical element 202 provided measuring point with respect to the x-direction x, the y-direction y and the z-direction z. Under the "orientation" of the optical element 202 or the optically effective area 210 is in particular its or its tilting with respect to the three spatial directions x , y , z to understand. That is, the optical element 202 or the optically effective area 210 can be tilted about the x-direction x, the y-direction y and / or the z-direction z. This results in the six degrees of freedom for the position and / or orientation of the optical element 202 or the optically effective area 210 .

A "position" of the optical element 202 or the optically effective area 210 includes both its or their position and their or their orientation. “Adjustment” is accordingly to be understood as meaning that both the orientation and the position of the optical element are preferred 202 can be changed to the optical element 202 or the optically effective area 210 to hold a target position.

The force actuator 212 or the force actuators 212 are with the help of a control unit 222 driven to the optical element 202 to adjust. However, only one force actuator is discussed below 212 received. The control unit 222 controls the force actuator 212 based on sensor data from a position sensor 224 on. The position sensor 224 detects an actual position of the optical element 202 or the optically effective area 210 . With the help of the force actuator 212 becomes the optical element 202 adjusted to keep it in its target position or to spend it in it. In other words, it becomes the optical element 202 held still against a reference. The control unit 222 , the force actuator 212 and the position sensor 224 are part of a control loop 226 of the optical system 200 .

In operation, for example in exposure mode, of the optical system 200 it may be necessary to dampen resonances that affect the control loop 226 let it become unstable. This applies in particular to higher-frequency resonances in the force actuator 212 and in the actuator 220 between the force actuator 212 and the optical element 202 .

In order to achieve this attenuation, the optical system includes 200 a damping device 300 that between the force actuator 212 and the optical element 202 is arranged. In particular, the damping device 300 in a power path FP arranged that the force F. through the optical system 200 takes. That is, the force F. is about the damping device 300 on the optical element 202 transfer. The damping device 300 can be a component made of an elastically deformable material, for example rubber. In particular, the material has viscoelastic properties. The elastic material behavior is with the help of a spring element 302 shown. The viscous material behavior will by a damping cylinder 304 shown. In that the damping device 300 in the power path FP is arranged, resonances can be dampened, which the control loop 226 could be left unstable.

3 shows a schematic sectional view of a further embodiment of an optical system 200 . The optical system 200 according to the 3 represents a concrete structural design of the optical system 200 according to the 2 represent.

The optical system 200 comprises an optical element as explained above 202 with an optically effective surface 210 and one of the optically effective surfaces 210 facing away from the rear 228 . The backside 228 is not optically effective. With the back 228 is a socket 230 firmly connected. For example, the socket 230 on the back 228 glued. An actuator as previously explained 220 is with the help of a joint 232 with the socket 230 coupled. The joint 232 can be a ball joint, a solid state joint or a combination of solid state joints.

In particular, the optical element 202 three such sockets 230 assigned, which are arranged in a triangle. Each socket 230 again are two force actuators 212 assigned to an adjustment of the optical element 202 in the six degrees of freedom.

The force actuator 212 includes in addition to a magnetic element as previously mentioned 216 a coil element 234 or several coil elements 234 . The coil element 234 or the coil elements 234 are with the solid world 218 connected. Only one coil element is discussed below 234 Referenced. The magnetic element 216 is in the coil element 234 and can be moved with the help of this in the y-direction. The magnetic element 216 includes a cylindrical cavity 235 , in which a cylindrical coupling element 236 is recorded. The coupling element 236 is with the help of another joint 237 , in particular a ball joint or a solid body joint, with the actuating element 220 connected.

The cavity 235 is stepped and has a circumferential shoulder at each end 238 , 240 on. The heels 238 , 240 are formed by the cavity 235 narrowed. The coupling element 236 also includes two paragraphs arranged at the end 242 , 244 . The heels 242 , 244 are formed by having a diameter of the coupling element 236 in the area of paragraphs 242 , 244 is reduced.

Between the coupling element 236 and the magnetic element 216 is a damping device 300 in the form of two damping elements 306 , 308 arranged. The damping elements 306 , 308 are ring-shaped. The damping elements 306 , 308 are between each paragraph 238 , 240 of the cavity 235 and the paragraphs 242 , 244 of the coupling element 236 positioned. The damping elements 306 , 308 can be O-rings.

One of the force actuator 212 exerted force as previously mentioned F. takes its path of strength FP (please refer 2 ) from the magnetic element 216 via the damping device 300 , the coupling element 236 , the joint 237 , the actuator 220 , the joint 232 and the socket 230 on the optical element 202 . The joints 232 , 237 cause that the force F. only along a central or symmetry axis 246 of the actuating element 220 can be transferred. This structure according to the 3 is particularly advantageous when the actuating element 220 shows little momentum.

4th shows a schematic perspective view of a further embodiment of an optical system 200 . 5 Fig. 10 shows a schematic sectional view of the optical system 200 . The optical system 200 according to the 4th and 5 also provides a concrete structural design of the optical system 200 according to the 2 represent.

In the 4th is the back 228 of the optical element 202 to see. At the back 228 is a cylindrical depression or recess 248 intended. In the recess 248 is a cylindrical mounting socket 250 intended. The fastening nozzle 250 is part of the optical element 202 . On the mounting socket 250 is a socket as mentioned before 230 intended. The socket 230 is ring-shaped. For example, the socket 230 on the mounting socket 250 glued. In the annular socket 230 is a connector 252 added to the with the help of the actuator, not shown 220 the force F. is applied. In particular, the connecting element 252 Part of the actuator 220 be.

A damping device 300 in the form of a sleeve-shaped body connects the connecting element 252 with the socket 230 . For example, the damping device 300 to the connecting element 252 and to the socket 230 vulcanized on. The power path FP the power F. runs from the connector 252 through the damping device 300 on the socket 230 and from there over the mounting socket 250 on the optical element 202 . The arrangement according to the 4th and 5 is particularly beneficial when the Force actuator 212 and the actuator 220 show a higher momentum.

6th shows a schematic sectional view of a further embodiment of an optical system 200 . The optical system too 200 according to the 6th represents a concrete structural design of the optical system 200 according to the 2 represent.

In the 6th is the optical element 202 with the optically effective surface 210 and the back 228 shown. There are three sockets on the back 230 provided, but only one of which is shown. The socket 230 is for example with the back 228 glued. The socket 230 are two force actuators 212 with magnetic elements 216 and coil elements 234 assigned. For example, there are central or symmetry axes 254 of the force actuators 212 positioned at an angle of 90 ° to each other.

The magnetic elements 216 are with the help of an actuator 220 connected to each other in the form of a triangular body. For example, the magnetic elements 216 on the actuator 220 unscrewed. Between the socket 230 and the actuator 220 is a damping device 300 arranged. The damping device 300 can be a disk-shaped rubber layer.

In the 6th is with a double arrow 256 an undesired waveform shown, with the help of the damping device 300 can be dampened. The power path FP runs here from the magnetic elements 216 by the actuator 220 and the damping device 300 into the socket 230 and from there into the optical element 202 .

7th Figure 12 shows a sectional view of a further embodiment of an optical system 200 . The optical system 200 according to the 7th is a further development of the optical system 200 according to the 6th . The following only looks at differences between these two optical systems 200 received.

The optical system 200 according to the 7th differs from the optical system 200 according to the 6th only by the fact that the damping device 300 is not disc-shaped, but hollow cylindrical. Even the socket 230 is hollow cylindrical. The actuator 220 comprises a cylindrical connecting extension 258 that is in the damping device 300 is recorded. The damping device 300 turn is in the socket 230 recorded. The damping device 300 can one to the actuator 220 and the socket 230 on vulcanized rubber layer.

8th Figure 12 shows a sectional view of a further embodiment of an optical system 200 . The optical system according to 8th is a further development of the optical system 200 according to the 6th . The following only looks at differences between these two optical systems 200 received.

In this embodiment of the optical system 200 comprises the damping device 300 - as with reference to 3 already explained - two damping elements 306 , 308 in the form of O-rings. The damping elements 306 , 308 can have different diameters. The damping element 306 lies on top of the socket 230 on. At the connecting process 258 is a surrounding paragraph 260 provided on which the damping element 306 is also present.

The socket 230 also includes a surrounding paragraph 262 on which the damping element 308 is applied. The damping element 308 is also on a disc 264 at that with the help of a fastener 266 , in particular a screw, with the connecting extension 258 is firmly connected. This can be done in the connection extension 258 a threaded hole 268 be provided. In the optical element 202 can be a breakthrough 270 be provided, the assembly of the fastener 266 allowed.

As with reference to the aforementioned embodiments of the optical system 200 explained, the damping device 300 be a layer made of an elastomer such as rubber. The elastomer can be a flat layer, a cylindrical layer or also conical. The damping device 300 can thus have any geometry. Furthermore, the damping device 300 also two damping elements 306 , 308 in the form of O-rings.

Should now for reasons of positional stability or to protect against failure of the damping device 300 , especially if the damping device 300 a layer of vulcanized elastomer is, to increase, yet an additional connection between the force actuator 212 and the optical element 202 provided, this can be done using the in the 2 shown spring element 302 happen. The spring element 302 is then installed parallel to the elastomer. In this way, the ratio of stiffness to damping can be influenced, since the stiffness of the spring element is part of the stiffness of the elastomer 302 to add is the spring element 302 however does not contribute to damping. However, this combination can also be used as a design parameter, for example in the event that an elastomer is selected for outgassing reasons which actually provides too much damping.

Although the present invention has been described on the basis of exemplary embodiments, it can be modified in many ways.

List of reference symbols

100A

EUV lithography system

100B

DUV lithography system

102

Beam shaping and lighting system

104

Projection system

106A

EUV light source

106B

DUV light source

108A

EUV radiation

108B

DUV radiation

110

mirror

112

mirror

114

mirror

116

mirror

118

mirror

120

Photomask

122

mirror

124

Wafer

126

optical axis

128

lens

130

mirror

132

medium

200

optical system

202

optical element

204

Dimensions

206

Dimensions

208

Spring element

210

optically effective area

212

Force actuator

214

Spring element

216

Magnetic element

218

fixed world

220

Actuator

222

Control unit

224

Position sensor

226

Control loop

228

back

230

Rifle

232

joint

234

Coil element

235

cavity

236

Coupling element

237

joint

238

paragraph

240

paragraph

242

paragraph

244

paragraph

246

Axis of symmetry

248

Recess

250

Mounting socket

252

Connecting element

254

Axis of symmetry

256

Double arrow

258

Connecting process

260

paragraph

262

paragraph

264

disc

266

Fastener

268

Threaded hole

270

breakthrough

300

Damping device

302

Spring element

304

Damping cylinder

306

Damping element

308

Damping element

F.

force

FP

Power path

M1

mirror

M2

mirror

M3

mirror

M4

mirror

M5

mirror

M6

mirror

x

x direction

y

y direction

z

z direction

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102011007917 A1 [0006]

Claims (15)

Optical system (200) for a lithography system (100A, 100B), having an optical element (202), a force actuator (212) which is configured to apply a force (F) to the optical element (202) in order to adjust it, and a damping device (300) for damping oscillation modes of the optical element (202), wherein the damping device (300) is arranged between the optical element (202) and the force actuator (212) in such a way that a force path (FP) of the force (F) takes its path via the damping device (300). Optical system according to Claim 1 , wherein the force actuator (212) for generating the force (F) has a magnetic element (216) and a coil element (234), the magnetic element (216) being coupled to the optical element (202) with the aid of an actuating element (220). Optical system according to Claim 2 , wherein the damping device (300) is arranged between the magnetic element (216) and the actuating element (220). Optical system according to Claim 2 or 3 , wherein the force actuator (212) has a coupling element (236) which is arranged within the magnetic element (216) and which is coupled to the actuating element (220), and wherein the damping device (300) between the magnetic element (216) and the coupling element (236) is arranged. Optical system according to Claim 2 , further comprising a socket (230) which is firmly connected to the optical element (202), wherein the damping device (300) is arranged between the socket (230) and the actuating element (220). Optical system according to one of the Claims 1 - 5 wherein the damping device (300) has two damping elements (306, 308), in particular O-rings. Optical system according to Claim 6 , wherein the damping elements (306, 308) have different dimensions. Optical system according to Claim 5 wherein the damping device (300) is disc-shaped. Optical system according to Claim 5 , wherein the socket (230) is ring-shaped, wherein a connecting element (252) is received in the socket (230), which is coupled to the actuating element (220), and wherein the damping device (300) between the socket (230) and the Connecting element (252) is arranged. Optical system according to Claim 5 or 9 , wherein the damping device (300) is vulcanized onto the bushing (230) and onto the connecting element (252). Optical system according to Claim 9 , wherein the damping device (300) is hollow cylindrical. Optical system according to one of the Claims 2 - 11 , wherein two force actuators (212) are provided which are coupled to a common actuating element (220). Optical system according to Claim 12 wherein the force actuators (212) are positioned perpendicular to each other. Optical system according to one of the Claims 1 - 13 , wherein the damping device (300) has a spring element (302) and a damping cylinder (304). Lithography system (100A, 100B) with at least one optical system (200) according to one of the Claims 1 - 14th .

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