DE102023204744A1 - OPTICAL SYSTEM AND PROJECTION EXPOSURE SYSTEM - Google Patents

Abstract

An optical system (100) for a projection exposure system (1), comprising an optical element (104), a mount (112) for supporting the optical element (104), a flushing hood (120) for flushing the optical element (104) with a flushing gas (G), and a connection arrangement (122A, 122B, 122C) for detachably connecting the flushing hood (120) to the mount (112), wherein the connection arrangement (122A, 122B, 122C) has a fastening section (136) provided on the mount (112), with the aid of which the flushing hood (120) is connected to the mount (112), and wherein the fastening section (136) is mechanically decoupled from the mount (112).

Description

The present invention relates to an optical system for a projection exposure apparatus and a projection exposure apparatus with such an optical system.

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

Driven by the pursuit of ever smaller structures in the manufacture of integrated circuits, DUV lithography systems are currently being developed that use light with a wavelength in the range of 30 nm to 250 nm. With such DUV lithography systems, it may be necessary to flush individual lenses with a flushing gas. For this purpose, a so-called flushing hood can be used, which is screwed to a mount of the respective lens. However, the screwing can introduce undesirable parasitic forces into the mount that supports the lens. This needs to be improved.

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

Accordingly, an optical system for a projection exposure system is proposed. The optical system comprises an optical element, a mount for supporting the optical element, a flushing hood for flushing the optical element with a flushing gas and a connection arrangement for detachably connecting the flushing hood to the mount, wherein the connection arrangement has a fastening section provided on the mount, with the aid of which the flushing hood is connected to the mount, and wherein the fastening section is mechanically decoupled from the mount.

Because the fastening section is mechanically decoupled from the frame, the introduction of parasitic forces into the frame and thus into the optical element is prevented or at least significantly reduced. This prevents any undesirable influence on the optical properties of the optical element.

The optical system is a projection optics or part of a projection optics. Therefore, the optical system can also be referred to as projection optics. The optical system is preferably suitable for both DUV lithography and EUV lithography. The projection exposure system can have several such optical systems.

The optical element is preferably a lens. However, the optical element can also be a mirror. However, it is assumed below that the optical element is a lens. The optical element can therefore also be referred to as a lens.

The optical element is at least partially accommodated in the frame. Accordingly, the fact that the frame “supports” the optical element is to be understood in particular as meaning that the frame can absorb the weight of the optical element.

The purge hood is in particular a lens bottom purge hood (LBPH). The purge hood covers the optical element. The optical element is arranged last in the beam path, in particular with respect to a beam path running through the optical system. Accordingly, the purge hood is also arranged at the end of the beam path. With the help of the purge hood, it is possible to purge the optical element with the purge gas, so that contamination of the optical element is prevented. The mount preferably comprises an end plate on which the purge hood is mounted.

The connection arrangement can be released and re-established as often as desired. The connection arrangement can comprise a screw connection with a fastening element in the form of a screw. The fastening section is preferably provided on the aforementioned end plate of the socket, in particular on a base section of the end plate. The fastening section is thus preferably part of the socket, in particular part of the end plate.

The fastening section can be cylindrical. The fastening section can have a central threaded hole in which a fastening element, in particular a screw, is accommodated in order to connect the flushing hood to the holder. In particular, the fastening section is mechanically decoupled from the end plate, in particular from a base section of the end plate.

The fact that the fastening section is "mechanically decoupled" from the socket means in particular that the fastening section cannot exert any forces on the socket or on the end plate. Accordingly, the transmission of forces between the fastening section and the socket is interrupted or significantly reduced. This prevents the introduction of parasitic forces into the socket or at least significantly reduces them.

According to one embodiment, the fastening section is connected to the socket by means of webs acting as solid-state joints.

In particular, the fastening section is connected to the end plate of the socket, in particular to the base section of the end plate, with the help of the webs. The fastening section, the webs and the socket or the end plate form a one-piece component, in particular a one-piece component. “One-piece” or “single-part” means in this case that the fastening section, the webs and the socket are not made of different sub-components, but form a common component. “One-piece” means in this case that the fastening section, the webs acting as solid-state joints and the socket are made entirely of the same material. In this case, a “solid-state joint” is to be understood in particular as an area of a component which allows a relative movement between two rigid body areas, in this case the fastening section and the socket or the end plate, by bending.

According to a further embodiment, first webs which are evenly distributed around the fastening section and second webs which are evenly distributed around the fastening section are provided, wherein the second webs are arranged between the fastening section and the first webs.

In particular, the fastening section is assigned a central or symmetry axis, to which the fastening section can be rotationally symmetrical. A radial direction of the connection arrangement is oriented perpendicular to the symmetry axis and away from it. In particular, the second webs are arranged between the fastening section and the first webs with respect to the radial direction. The number of first webs and second webs is arbitrary. In particular, three first webs and three second webs are provided in each case.

According to a further embodiment, the first webs and the second webs are arranged radially and/or circumferentially offset from one another.

For example, the first webs are each arranged offset by 120° from one another. Accordingly, the second webs can also be arranged offset by 120° from one another. In this case, the second webs are arranged within the first webs when viewed in the radial direction. The fact that the first webs and the second webs are arranged “radially” offset from one another means in particular that the first webs and the second webs are arranged at different distances from the axis of symmetry and thus also from the fastening section when viewed in the radial direction. The fact that the first webs and the second webs are arranged “circumferentially” offset from one another means in particular that the first webs and the second webs are arranged such that, viewed along a circumferential direction of the connection arrangement, a second web is arranged between two first webs and a first web is arranged between two second webs. The first webs and the second webs can, for example, be arranged circumferentially offset from one another by 45°.

According to a further embodiment, circumferential cutouts are provided around the fastening section, which separate the fastening section from the socket, wherein the webs and the cutouts are arranged alternately.

Preferably, the webs and the cutouts are provided on a wall which connects the fastening section to the socket, in particular to the end plate of the socket. The cutouts are in particular designed as openings which break through this wall. The cutouts can each run in a ring around the fastening section. First cutouts and second cutouts are preferably provided. The first cutouts enclose the second cutouts, which in turn enclose the fastening section. Viewed along the radial direction, the second cutouts are arranged between the fastening section and the first cutouts.

According to a further embodiment, first cutouts are provided which are evenly distributed around the fastening section and second cutouts are provided which are evenly distributed around the fastening section, wherein the second cutouts are arranged between the fastening section and the first cutouts.

The first cutouts form an annular geometry that runs completely around the fastening section. The annular geometry is only interrupted by the first webs. Accordingly, the second cutouts also form an annular geometry that runs completely around the fastening section. The annular geometry of the second cutouts is only interrupted by the second webs.

According to a further embodiment, the fastening section is connected to the socket by means of a membrane.

In this case, a "membrane" is understood to mean an area of the frame which has very thin walls compared to the rest of the frame, so that the membrane can be elastically deformed. The fastening section is connected to the end plate of the frame or to the base section of the end plate using the membrane.

According to a further embodiment, the membrane has an inner wall surrounding the fastening section, an outer wall surrounding the inner wall and an end wall connecting the inner wall to the outer wall.

This means in particular that the membrane has a U-shaped geometry in cross-section. In terms of the radial direction, the inner wall is arranged within the outer wall. The end wall connects the inner wall to the outer wall. This previously described geometry of the membrane can achieve increased flexibility of the membrane.

According to a further embodiment, the optical system further comprises a fastening element by means of which the fastening section is connected to the rinsing hood.

The fastening element is in particular a screw. The fastening element is screwed into the threaded hole of the fastening section. The fastening element rests on the flushing hood. Because the fastening section is mechanically decoupled from the frame, any parasitic forces introduced by the fastening element are not transferred to the frame and thus to the optical element.

According to a further embodiment, the optical system further comprises a receiving portion provided on the mount and a connecting portion provided on the rinsing hood, on which the fastening element is supported, wherein the connecting portion is received in the receiving portion.

The receiving section of the socket is pot-shaped or hollow-cylindrical. The receiving section is closed off at the front by the previously mentioned wall on which the fastening section is provided. The connecting section of the flushing hood is cylindrical. The connecting section has a central hole through which the fastening element is passed.

According to a further embodiment, the connecting portion is supported on the fastening portion.

This means in particular that the connecting section rests against the fastening section. In the event that the fastening section is connected to the socket using the membrane, a gap can be provided between the connecting section and the fastening section. In this case, the receiving section of the socket rests against a base section of the flushing hood.

Furthermore, an optical system for a projection exposure system is proposed. The optical system has an optical element, a mount for supporting the optical element, a flushing hood for flushing the optical element with a flushing gas and a connection arrangement for detachably connecting the flushing hood to the mount, wherein the connection arrangement magnetically connects the flushing hood to the mount.

The magnetic connection between the rinsing hood and the frame can also prevent or at least significantly reduce the introduction of parasitic forces into the frame and thus into the optical element. The rinsing hood and/or the frame can have a magnetic element for the magnetic connection.

According to one embodiment, the socket is made of a non-magnetic material, wherein a magnetic element and/or a magnetic component is provided on or in the socket.

For example, the frame is made of a non-magnetic steel alloy. However, other materials can also be used. The magnetic element can be made of molybdenum or a material containing molybdenum. The magnetic element and/or the magnetic component can be glued to the frame or screwed to it. The magnetic element is in particular a permanent magnet. In this case, a “magnetic component” is understood to mean a component that is ferromagnetic. has magnetic properties. For example, the magnetic component is made of steel.

According to a further embodiment, the rinsing hood has a magnetic element which interacts with the magnetic element and/or the magnetic component of the socket.

For example, the magnetic element of the rinsing hood is glued or screwed to the rinsing hood. Several magnetic elements can be provided on the rinsing hood.

Furthermore, a projection exposure system with such an optical system is proposed.

The optical system is preferably a projection optics of the projection exposure system. However, the optical system can also be an illumination system. The projection exposure system can be an EUV lithography system. EUV stands for "Extreme Ultraviolet" and refers to a wavelength of the working light between 0.1 nm and 30 nm. The projection exposure system can also be a DUV lithography system. DUV stands for "Deep Ultraviolet" and refers to a wavelength of the working light between 30 nm and 250 nm.

In this case, "one" is not necessarily to be understood as being limited to just one element. Rather, several elements, such as two, three or more, can also be provided. Any other counting word used here should not be understood as meaning that there is a limitation to the exact number of elements mentioned. Rather, numerical deviations upwards and downwards are possible, unless otherwise stated.

The embodiments and features described for the optical system apply accordingly to the proposed projection exposure system and vice versa.

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

• 1 zeigt einen schematische Ansicht einer Ausführungsform einer Projektionsbelichtungsanlage für die DUV-Projektionslithographie;
• 2 zeigt eine schematische Schnittansicht einer Ausführungsform eines optischen Systems für die Projektionsbelichtungsanlage gemäß 1;
• 3 zeigt die Detailansicht III gemäß 2;
• 4 zeigt die Ansicht IV gemäß 3;
• 5 zeigt eine schematische Schnittansicht einer Ausführungsform einer Verbindungsanordnung für das optische System gemäß 2;
• 6 zeigt eine schematische Schnittansicht einer weiteren Ausführungsform einer Verbindungsanordnung für das optische System gemäß 2;
• 7 zeigt eine schematische Schnittansicht einer weiteren Ausführungsform einer Verbindungsanordnung für das optische System gemäß 2;
• 8 zeigt eine schematische Schnittansicht einer weiteren Ausführungsform einer Verbindungsanordnung für das optische System gemäß 2;
• 9 zeigt eine schematische Seitenansicht der Verbindungsanordnung gemäß 8;
• 10 zeigt eine schematische Aufsicht der Verbindungsanordnung gemäß 8;
• 11 zeigt eine schematische Seitenansicht einer Ausführungsform eines Positionierelements für die Verbindungsanordnung gemäß 8;
• 12 zeigt eine schematische Aufsicht des Positionierelements gemäß 11; und
• 13 zeigt eine schematische Schnittansicht einer weiteren Ausführungsform einer Verbindungsanordnung für das optische System gemäß 2.

Further advantageous embodiments and aspects of the invention are the subject of the dependent claims and the embodiments of the invention described below. The invention is explained in more detail below using preferred embodiments with reference to the attached figures.

• 1 shows a schematic view of an embodiment of a projection exposure system for DUV projection lithography;
• 2 shows a schematic sectional view of an embodiment of an optical system for the projection exposure apparatus according to 1 ;
• 3 shows the detail view III according to 2 ;
• 4 shows view IV according to 3 ;
• 5 shows a schematic sectional view of an embodiment of a connection arrangement for the optical system according to 2 ;
• 6 shows a schematic sectional view of another embodiment of a connection arrangement for the optical system according to 2 ;
• 7 shows a schematic sectional view of another embodiment of a connection arrangement for the optical system according to 2 ;
• 8th shows a schematic sectional view of another embodiment of a connection arrangement for the optical system according to 2 ;
• 9 shows a schematic side view of the connection arrangement according to 8th ;
• 10 shows a schematic plan view of the connection arrangement according to 8th ;
• 11 shows a schematic side view of an embodiment of a positioning element for the connection arrangement according to 8th ;
• 12 shows a schematic plan view of the positioning element according to 11 ; and
• 13 shows a schematic sectional view of another embodiment of a connection arrangement for the optical system according to 2 .

In the figures, identical or functionally equivalent elements have been given the same reference symbols unless otherwise stated. It should also be noted that the representations in the figures are not necessarily to scale.

1 shows a schematic view of a projection exposure system 1, in particular a DUV lithography system, which comprises a beam shaping and illumination system 2 (here also referred to as “illumination optics”) and a Projection optics 4 (here also referred to as “projection lens”). DUV stands for “deep ultraviolet” (DUV) and refers to a wavelength of the working light between 30 nm and 250 nm.

The beam shaping and illumination system 2 and the projection optics 4 are preferably each arranged in a vacuum housing (not shown). Each vacuum housing is evacuated using an evacuation device (not shown). The vacuum housings are surrounded by a machine room (not shown), in which drive devices for mechanically moving or adjusting optical elements can be provided. Furthermore, electrical controls and the like can also be arranged in the machine room.

The projection exposure system 1 has a light source 6. The light source 6 can be, for example, an ArF excimer laser which emits radiation 8 in the DUV range at, for example, 193 nm. The radiation 8 is bundled in the beam shaping and illumination system 2 and a desired operating wavelength (working light) is filtered out of the radiation 8. The beam shaping and illumination system 2 can have optical elements (not shown), such as mirrors or lenses.

After passing through the beam shaping and illumination system 2, the radiation 8 is directed onto a photomask (reticle) 10. The photomask 10 is designed as a transmissive optical element and can be arranged outside the beam shaping and illumination system 2 and the projection optics 4. The photomask 10 has a structure which is imaged in reduced size onto a wafer 12 by means of the projection optics 4.

The projection optics 4 have a plurality of lenses 14, 16, 18 and/or mirrors 20, 22 for imaging the photomask 10 onto the wafer 12. Individual lenses 14, 16, 18 and/or mirrors 20, 22 of the projection optics 4 can be arranged symmetrically to an optical axis 24 of the projection optics 4. It should be noted that the number of lenses 14, 16, 18 and mirrors 20, 22 shown here is purely exemplary and is not limited to the number shown. More or fewer lenses 14, 16, 18 and/or mirrors 20, 22 can also be provided.

An air gap between a last lens (not shown) and the wafer 12 can be replaced by a liquid medium 26 having a refractive index > 1. The liquid medium 26 can be, for example, high-purity water. Such a structure is also referred to as immersion lithography and has an increased photolithographic resolution. The medium 26 can also be referred to as an immersion liquid.

2 shows a schematic sectional view of an embodiment of an optical system 100 for the projection exposure apparatus 1.

The optical system 100 is a projection optics 4 as mentioned above or part of such a projection optics 4. Therefore, the optical system 100 can also be referred to as projection optics. The optical system 100 is assigned a central or symmetry axis 102. The symmetry axis 102 can be identical to the optical axis 24.

The optical system 100 comprises an optical element 104. The optical element 104 is a lens. The optical element 104 can also be a mirror. However, it is assumed below that the optical element 104 is a lens. The optical element 104 can be the lens 18 of the projection optics 4.

The optical element 104 can be constructed rotationally symmetrically to the axis of symmetry 102. The optical element 104 has a front side 106 facing the wafer 12 and a rear side 108 facing away from the wafer 12. The radiation 8 enters the optical element 104 at the rear side 108 and exits it again at the front side 106. The optical element 104 can be frustoconical with a conical outer surface 110. In principle, however, the optical element 104 can have any geometry.

The optical system 100 further comprises a mount 112 that carries the optical element 104. The mount 112 is made of a non-magnetic or amagnetic material, in particular of a metallic material. For example, an amagnetic steel alloy can be used for this purpose. However, other non-magnetic materials are also conceivable. This enables the use of the mount 112 in a magnetic field.

The mount 112 has a cover plate 114 which is disk-shaped or ring-shaped. The optical element 104 can rest on the cover plate 114. The cover plate 114 faces the wafer 12. The mount 112 also has a flange section 116 which is also ring-shaped. For example, the mount 112 can be mounted on a support structure (not shown) using the flange section 116.

A diameter of the flange section 116 is larger than a diameter of the end plate 114. Between the end plate 114 and the flange section 116, a frustoconical receiving section 118 is provided, which receives the optical element 104. For this purpose, the lateral surface 110 can rest on the inside of the receiving section 118.

A lens bottom purge hood 120 (LBPH) is attached to the mount 112, in particular to the cover plate 114, with the aid of which the optical element 104 can be purged with a purge gas G. For this purpose, the purge gas G is supplied through a suitable inlet and discharged from the optical element 104 again via a suitable outlet. The purge hood 120 is a lens purge hood and can therefore also be referred to as such. The purge hood 120 is frame-shaped.

The flushing hood 120 is detachably connected to the socket 112. For this purpose, for example, a screw connection and/or a magnetic connection can be provided, with the aid of which the flushing hood 120 is detachably connected to the socket 112. "Detachable" here means in particular that the flushing hood 120 can be connected to the socket 112 and separated from it again as often as desired.

When connecting the rinsing hood 120 and the end plate 114, care must be taken to ensure that no parasitic forces are introduced into the mount 112 through this connection, since these could otherwise be introduced into the optical element 104 and thus influence the optical properties of the optical element 104 in an undesirable manner.

3 shows the detail view III according to the 2 . 4 shows view IV according to the 3 . The following refers to the 3 and 4 referred to at the same time.

The 3 shows in particular a sectional view of an embodiment of a connection arrangement 122A. The flushing hood 120 is detachably connected to the end plate 114 of the mount 112 by means of the connection arrangement 122A. The optical system 100 can have several such connection arrangements 122A. For example, three connection arrangements 122A are provided.

The connection arrangement 122A is assigned a central or symmetry axis 124. The end plate 114 comprises a frame-shaped base section 126. The base section 126 can be rectangular. A tubular or hollow-cylindrical receiving section 128 is provided on the base section 126. The receiving section 128 is constructed rotationally symmetrically to the symmetry axis 124.

The receiving section 128 comprises a cylindrical wall 130 with an annular contact surface 132 provided on the front side. Away from the contact surface 132, the receiving section 128 has a receiving section 128 in the orientation of the 3 wall 134 which closes off at the top. The receiving section 128 is pot-shaped.

In the orientation of the 3 On the top, a cylindrical fastening section 136 extends out of the wall 134. The fastening section 136 is constructed rotationally symmetrically to the axis of symmetry 124. A threaded hole 138 is provided on or in the fastening section 136. The threaded hole 138 is constructed rotationally symmetrically to the axis of symmetry 124.

The fastening section 136 has an end face 140 facing away from the flushing hood 120 and a contact surface 142 facing the flushing hood 120. The contact surface 142 is ring-shaped and runs completely around the axis of symmetry 124. The fastening section 136 rests against the flushing hood 120 with the contact surface 142.

As the 4 shows, several cutouts 144, 146, 148 are provided in the wall 134, which run in a ring around the fastening section 136 and break through the wall 134 except for webs 150, 152, 154 provided between the cutouts 144, 146, 148. A “cutout” is therefore to be understood as a breakthrough or an opening which breaks through the wall 134.

The cutouts 144, 146, 148 and the webs 150, 152, 154 are arranged alternately, so that a web 150, 152, 154 is arranged between two cutouts 144, 146, 148 and vice versa. The cutouts 144, 146, 148 can also be referred to as first cutouts. The webs 150, 152, 154 can also be referred to as first webs.

Between the cutouts 144, 146, 148 and the fastening section 136, further cutouts 156, 158, 160 are provided, which break through the wall 134 up to the webs 162, 164, 166 provided between the cutouts 156, 158, 160. The cutouts 156, 158, 160 run in a ring around the fastening section 136. The webs 150, 152, 154, 162, 164, 166 connect the fastening section 136 with the wall 134.

The cutouts 156, 158, 160 and the webs 162, 164, 166 are arranged alternately, so that a web 162, 164, 166 is arranged between two cutouts 156, 158, 160 and vice versa. The cutouts 156, 158, 160 can also be referred to as second cutouts. The webs 162, 164, 166 can also be referred to as second webs.

With respect to a radial direction R, which is oriented perpendicular to the axis of symmetry 124 and away from it, the cutouts 156, 158, 160 are placed within the cutouts 144, 146, 148. The cutouts 144, 146, 148 and the cutouts 156, 158, 160 are placed offset from one another, so that the webs 150, 152, 154 and the webs 162, 164, 166 are also arranged offset from one another. For example, the webs 150, 152, 154 and the webs 162, 164, 166 can be arranged offset from one another by 45°.

The webs 150, 152, 154, 162, 164, 166 function as solid-body joints and can therefore also be referred to as such. In the present case, a "solid-body joint" is to be understood in particular as an area of a component which allows a relative movement between two rigid-body areas, in this case the wall 134 and the fastening section 136, by bending.

With the help of the cutouts 144, 146, 148, 156, 158, 160, the stiffness of the wall 134 can be varied, in particular reduced. The term "stiffness" refers in particular to the resistance of a body, in this case the wall 134, to an elastic deformation imposed by an external load. The stiffness conveys the connection between the load on the body and its deformation. The stiffness is determined by the material and the geometry of the body.

The flushing hood 120 has a frame-shaped base section 168. A cylindrical connecting section 170 extends out of the base section 168. The connecting section 170 has an annular contact surface 172 against which the contact surface 142 rests. The connecting section 170 is constructed rotationally symmetrically to the axis of symmetry 124. The connecting section 170 is received in the receiving section 128. The connecting section 170 has a central bore 174. The bore 174 is a stepped bore.

The connection arrangement 122A further comprises a fastening element 176, in particular a screw. The fastening element 176 is received in the bore 174. The fastening element 176 has a head portion 178 which is supported on the connection portion 170. In addition to the head portion 178, the fastening element 176 has a threaded portion 180 which is screwed into the threaded bore 138 and a shaft portion 182 which is arranged between the head portion 178 and the threaded portion 180.

The fastening element 176 connects the connecting section 170 of the flushing hood 120 to the fastening section 136 of the end plate 114 of the holder 112. The fastening element 176 presses the contact surfaces 142, 172 against each other. A gap is provided between the contact surface 132 and the base section 168 of the flushing hood 120 so that the contact surface 132 does not contact the base section 168.

Because the fastening section 136 is only connected to the wall 134 with the aid of the webs 150, 152, 154, 162, 164, 166, it is possible to mechanically decouple the fastening section 136, which is firmly connected to the connecting section 170 with the aid of the fastening element 176, from the end plate 114 of the socket 112 by means of a suitable design of the webs 150, 152, 154, 162, 164, 166 or the cutouts 144, 146, 148, 156, 158, 160.

In the present case, “mechanical decoupling” is to be understood in particular to mean that the cutouts 144, 146, 148, 156, 158, 160 prevent or at least reduce a force transmission between the fastening section 136 and the wall 134. Forces can only be transmitted via the thin webs 150, 152, 154, 162, 164, 166, which function as solid-state joints.

The webs 150, 152, 154, 162, 164, 166 enable a tilting of the fastening section 136 relative to the wall 134, an axial movement of the fastening section 136 relative to the wall 134 along the axis of symmetry 124 and/or a radial movement of the fastening section 136 relative to the wall 134 along the radial direction R and against the radial direction R.

Because the cutouts 144, 146, 148, 156, 158, 160 are provided, the connection arrangement 122A does not introduce any parasitic forces into the end plate 114 of the mount 112 and thus also into the optical element 104. The connection arrangement 122A is easy to assemble and easy to manufacture. The cutouts 144, 146, 148, 156, 158, 160 can be introduced by means of eroding cuts.

5 shows a schematic sectional view of another embodiment of a connection arrangement 122B.

The connection arrangement 122B differs from the connection arrangement 122A essentially in that the fastening section 136 is not connected to the receiving section 128 of the end plate 114 with the aid of a thin-walled membrane 184 as mentioned above, but rather with the aid of a thin-walled membrane 184. The membrane 184 is disk-shaped and runs completely around the axis of symmetry 124. In this case, a "membrane" is understood to mean a thin-walled and film-like component.

The membrane 184, the fastening section 136 and the base section 126 can form a one-piece component, in particular a one-piece component. “One-piece” or “single-part” means that the membrane 184, the fastening section 136 and the base section 126 are not made up of different sub-components, but rather form a common component. “One-piece” means that the membrane 184, the fastening section 136 and the base section 126 are made entirely of the same material. However, a welded bellows can also be used as the membrane 184.

In this case, the contact surface 132 of the receiving section 128 rests against the base section 168 of the rinsing hood 120. The two contact surfaces 142, 172 do not contact each other, so that a gap is provided between them.

The membrane 184 enables a mechanical decoupling of the fastening section 136 from the base section 126. Thus, with the help of the connection arrangement 122B, the introduction of parasitic forces into the mount 112 and thus also into the optical element 104 is prevented.

6 shows a schematic sectional view of another embodiment of a connection arrangement 122C.

The connection arrangement 122C differs from the connection arrangement 122B only in that no disk-shaped membrane 184 is provided between the fastening section 136 and the receiving section 128, but rather a membrane 186 with a channel-shaped or U-shaped cross section.

The membrane 186 comprises an outer wall 188 connected to the fastening section 136, which runs around the axis of symmetry 124, an inner wall 190 connected to the receiving section 128, which runs around the axis of symmetry 124, and an end wall 192 connecting the walls 188, 190 to one another. The inner wall 190 is placed between the outer wall 188 and the fastening section 136.

In this case too, the contact surface 132 of the receiving section 128 rests against the base section 168 of the rinsing hood 120. The two contact surfaces 142, 172 do not contact each other, so that a gap is provided between them.

The membrane 186 enables a mechanical decoupling of the fastening section 136 from the base section 126. Thus, with the help of the connection arrangement 122C, the introduction of parasitic forces into the mount 112 and thus also into the optical element 104 is prevented.

7 shows a schematic sectional view of another embodiment of a connection arrangement 122D.

The connection arrangement 122D has a magnetic element 194 which is glued into the end plate 114 or screwed to it. The fastening element 176 is a steel screw in this case. The fastening element 176 is accommodated in the magnetic element 194. For this purpose, the magnetic element 194 has a bore 196. The bore 196 can, as shown in the 7 shown, a threaded hole. However, this is not mandatory.

However, the bore 196 can also be smooth on the inside (not shown). This means that the bore 196 does not necessarily have a thread. In this case, the fastening element 176 is only inserted into the bore 196 and is held there by the magnetic element 194. For this purpose, the magnetic element 194 interacts magnetically with the fastening element 176. Particularly preferably, pure contact is provided between the magnetic element 194 and the fastening element 176, without the bore 196 being a threaded bore.

8th shows a schematic sectional view of another embodiment of a connection arrangement 122E. 9 shows a schematic side view of the connection arrangement 122E. 10 shows a schematic plan view of the connection arrangement 122E. The following is the 8 to 10 referred to at the same time.

In this embodiment of the connection arrangement 122E, a magnetic element 198 is also provided, which is glued or screwed to the end plate 114 of the socket 112. The rinsing hood 120 has a magnetic element 200 corresponding to the magnetic element 198, which can be glued or screwed to the base section 168.

To position the flushing hood 120 on the end plate 114, the flushing hood 120 has, as shown in the 9 and 10 shown, several positioning elements 202, 204, 206. The positioning elements 202, 204, 206 can be screws. Each positioning element 202, 204, 206 has, as shown in the 11 and 12 shown, a head section 208, a shaft section 210 and a positioning section 212. The positioning section 212 comprises two positioning surfaces 214, 216 oriented obliquely to one another.

The head section 208 rests against a contact surface 218 provided on the flushing hood 120. The shaft section 210 is guided through a bore 220 provided in the flushing hood 120. A fit of H7/g6 can be provided here. The positioning elements 202, 204, 206 can each be in two parts. For example, the shaft section 210 is guided through the bore 220. The positioning section 212 is then connected to the shaft section 210, in particular welded. The positioning elements 202, 204, 206 are then securely connected to the flushing hood 120.

However, the fit at the bore 220 is not absolutely necessary. It is also possible that the bore 220 has such a large diameter that the positioning section 212 can be guided through the bore 220.

On the end plate 114 there are receiving elements 222, 224 ( 9 ). The receiving elements 222, 224 can receive the positioning sections 212 of the positioning elements 202, 204, 206. The positioning element 202 is arranged rotated by 90° with respect to the positioning elements 204, 206.

13 shows a schematic sectional view of another embodiment of a connection arrangement 122F.

In this embodiment of the connection arrangement 122F, a magnetic component 226 is glued to the end plate 114 or screwed to the end plate 114. Preferably, three of these magnetic components 226 are provided. More than three magnetic components 226 can also be provided. The flushing hood 120 has a magnetic element 200 as previously explained. The magnetic element 200 is a permanent magnet. A "magnetic component" is understood here to mean a component that has ferromagnetic properties. For example, the magnetic component 226 can be a steel component.

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

LIST OF REFERENCE SYMBOLS

1

Projection exposure system

2

Beam shaping and lighting system

4

Projection optics

6

Light source

8th

radiation

10

Photomask

12

Wafer

14

lens

16

lens

18

lens

20

Mirror

22

Mirror

24

optical axis

26

medium

100

Optical system

102

Axis of symmetry

104

Optical element

106

front

108

back

110

Shell surface

112

Version

114

End plate

116

Flange section

118

Recording section

120

Rinse hood

122A

Connection arrangement

122B

Connection arrangement

122C

Connection arrangement

122D

Connection arrangement

122E

Connection arrangement

122F

Connection arrangement

124

Axis of symmetry

126

Base section

128

Recording section

130

Wall

132

Contact surface

134

Wall

136

Mounting section

138

Threaded hole

140

Frontal area

142

Contact surface

144

Free cut

146

Free cut

148

Free cut

150

web

152

web

154

web

156

Free cut

158

Free cut

160

Free cut

162

web

164

web

166

web

168

Base section

170

Connecting section

172

Contact surface

174

drilling

176

Fastener

178

Head section

180

Thread section

182

Shaft section

184

membrane

186

membrane

188

Exterior wall

190

Inner wall

192

Front wall

194

Magnetic element

196

drilling

198

Magnetic element

200

Magnetic element

202

Positioning element

204

Positioning element

206

Positioning element

208

Head section

210

Shaft section

212

Positioning section

214

Positioning surface

216

Positioning surface

218

Contact surface

220

drilling

222

Recording element

224

Recording element

226

Component

G

Purge gas

R

Radial direction

Claims (15)

Optical system (100) for a projection exposure system (1), comprising an optical element (104), a mount (112) for supporting the optical element (104), a flushing hood (120) for flushing the optical element (104) with a flushing gas (G), and a connection arrangement (122A, 122B, 122C) for detachably connecting the flushing hood (120) to the mount (112), wherein the connection arrangement (122A, 122B, 122C) has a fastening section (136) provided on the mount (112), with the aid of which the flushing hood (120) is connected to the mount (112), and wherein the fastening section (136) is mechanically decoupled from the mount (112). Optical system according to Claim 1 , wherein the fastening section (136) is connected to the socket (112) by means of webs (150, 152, 154, 162, 164, 166) acting as solid-state joints. Optical system according to Claim 2 , wherein first webs (150, 152, 154) are arranged evenly distributed around the fastening section (136) and second webs (162, 164, 166) are arranged evenly distributed around the fastening section (136), and wherein the second webs (162, 164, 166) are arranged between the fastening section (136) and the first webs (150, 152, 154). Optical system according to Claim 3 , wherein the first webs (150, 152, 154) and the second webs (162, 164, 166) are arranged radially and/or circumferentially offset from one another. Optical system according to one of the Claims 2 - 4 , wherein circumferential cutouts (144, 146, 148, 156, 158, 160) are provided around the fastening section (136) which separate the fastening section (136) from the socket (112), and wherein the webs (150, 152, 154, 162, 164, 166) and the cutouts (144, 146, 148, 156, 158, 160) are arranged alternately. Optical system according to Claim 5 , wherein first cutouts (144, 146, 148) are provided which are evenly distributed around the fastening section (136), and second cutouts (156, 158, 160) are provided which are evenly distributed around the fastening section (136), and wherein the second cutouts (156, 158, 160) are arranged between the fastening section (136) and the first cutouts (144, 146, 148). Optical system according to Claim 1 , wherein the fastening section (136) is connected to the socket (112) by means of a membrane (184, 186). Optical system according to Claim 7 , wherein the membrane (186) has an inner wall (190) surrounding the fastening section (136), an outer wall (188) surrounding the inner wall (190) and an end wall (192) connecting the inner wall (190) to the outer wall (188). Optical system according to one of the Claims 1 - 8th , further comprising a fastening element (176), by means of which the fastening section (136) is connected to the rinsing hood (120). Optical system according to Claim 9 , further comprising a receiving portion (128) provided on the socket (112) and a connecting portion (170) provided on the rinsing hood (120), on which the fastening element (176) is supported, wherein the connecting portion (170) is received in the receiving portion (128). Optical system according to Claim 10 , wherein the connecting portion (170) is supported on the fastening portion (136). Optical system (100) for a projection exposure system (1), comprising an optical element (104), a mount (112) for supporting the optical element (104), a flushing hood (120) for flushing the optical element (104) with a flushing gas (G), and a connection arrangement (122D, 122E, 122F) for detachably connecting the flushing hood (120) to the mount (112), wherein the connection arrangement (122D, 122E, 122F) magnetically connects the flushing hood (120) to the mount (112). Optical system according to Claim 12 , wherein the socket (112) is made of a non-magnetic material, and wherein a magnetic element (194, 198) and/or a magnetic component (226) is provided on or in the socket (112). Optical system according to Claim 13 , wherein the rinsing hood (120) has a magnetic element (200) which interacts with the magnetic element (194, 198) and/or the magnetic component (226) of the socket (112). Projection exposure system (1) with an optical system (100) according to one of the Claims 1 - 14 .

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