DE102023200423A1 - COOLING DEVICE FOR A LITHOGRAPHY SYSTEM, LITHOGRAPHY SYSTEM AND METHOD FOR DAMPENING A PRESSURE Fluctuation of a LIQUID IN A LIQUID LINE OF A COOLING DEVICE OF A LITHOGRAPHY SYSTEM - Google Patents

Abstract

Cooling device (100) for a lithography system (1), comprising: a liquid line (104) for transporting a liquid (106) along an axial direction (A) of the liquid line (104), a magnetic float element (122) arranged within the liquid line (104). ) with a pressure-active surface (124, 126) for axially receiving or releasing pressure (P) from or to the liquid (106), and a magnetic field generating device (128) for axially applying a magnetic force (FE.) to the float element (122). ).

Description

The present invention relates to a cooling device for a lithography system, a lithography system with such a cooling device and a method for dampening a pressure fluctuation of a liquid in a liquid line of a cooling device of a lithography system.

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

Driven by the pursuit of ever smaller structures in the production of integrated circuits, EUV lithography systems are currently being developed which use light with a wavelength in the range from 0.1 nm to 30 nm, in particular 13.5 nm. Since most materials absorb light of this wavelength, reflective optics, i.e. mirrors, must be used in such EUV lithography systems instead of - as before - refracting optics, i.e. lenses.

The demands on the accuracy and precision of the imaging properties of lithography systems are constantly increasing. From a dynamic perspective, it is important to minimize the influence of interference on the movement of various components of the lithography system. For example, very precise positioning of optical components, in particular mirrors, of the lithography system is required. Dynamic interference from optical components can be generated, for example, by the movement of other components of the lithography system or by acoustic interference. Acoustic disturbances are transmitted, for example, as longitudinal waves through cooling liquids in cooling lines of a cooling device of the optical component.

As the complexity of lithography systems continues to increase, further dynamic interference excitations inside and outside the system are to be expected, so that additional mechanisms for their suppression or compensation are desirable and necessary.

Against this background, an object of the present invention is to provide an improved cooling device for a lithography system and an improved method for dampening a pressure fluctuation of a liquid in a liquid line of a cooling device of a lithography system.

• eine Flüssigkeitsleitung zum Transportieren einer Flüssigkeit entlang einer axialen Richtung der Flüssigkeitsleitung,
• ein innerhalb der Flüssigkeitsleitung angeordnetes magnetisches Schwimmerelement mit einer druckaktiven Oberfläche zur axialen Aufnahme oder Abgabe von Druck von der bzw. an die Flüssigkeit, und
• eine Magnetfelderzeugungseinrichtung zum axialen Beaufschlagen des Schwimmerelements mit einer magnetischen Kraft.

Accordingly, a cooling device for a lithography system is proposed. The cooling device has:

• a liquid line for transporting a liquid along an axial direction of the liquid line,
• a magnetic float element arranged within the liquid line with a pressure-active surface for axially receiving or releasing pressure from or to the liquid, and
• a magnetic field generating device for axially applying a magnetic force to the float element.

The magnetic float element arranged within the liquid line is in direct contact with the liquid flowing through the line. The pressure-active surface of the float element can absorb pressure from the liquid or release pressure to the liquid. A pressure fluctuation in the liquid can therefore be changed using the float element. By (non-contact) actuating the float element by means of the magnetic field generated by the magnetic field generating device, the float element can be used for passive and/or active damping of pressure fluctuations in the liquid.

Because the float element with its pressure-active surface is integrated directly into the flowing coolant, there are no parallel structures in the liquid circuit, e.g. B. Parallel structures to and/or branches from the cooling line are required. This is advantageous because every deflection and branching of the cooling line can be a source of flow-induced vibrations (FIV).

The liquid (e.g. coolant) is transported through the liquid pipe along the axial direction of the liquid pipe. In other words, a flow direction of the liquid is parallel to the axial direction of the liquid line. The pressure-active surface of the float element is arranged such that it can absorb or release pressure from or to the liquid in the axial direction. For example, the pressure-active surface of the float element is transverse and/or perpendicular to the axial Direction arranged. Furthermore, the magnetic force generated by the magnetic field generating device acts in the axial direction.

The proposed cooling device makes it possible to compensate for a pressure fluctuation in the coolant before it is passed on to a component to be cooled. This means that a change in position of the component to be cooled caused by pressure fluctuations in the coolant can be reduced or avoided. Pressure fluctuations in the coolant can be passively and/or actively suppressed by the cooling device.

The cooling device is set up, for example, to cool one or more optical or mechanical components of the lithography system. The optical component can be, for example, a mirror of the lithography system. The mechanical component can be, for example, a sensor frame of the lithography system.

The lithography system is, for example, an EUV or a DUV lithography system. EUV stands for “extreme ultraviolet” (EUV) and refers to a wavelength of work light in the range from 0.1 nm to 30 nm, in particular 13.5 nm. Furthermore, DUV stands for “deep ultraviolet” (Engl .: deep ultraviolet, DUV) and refers to a wavelength of work light between 30 nm and 250 nm.

The EUV or DUV lithography system includes an illumination system and a projection system. In particular, with the EUV or DUV lithography system, the image of a mask (reticle) illuminated by the lighting system is projected by means of the projection system onto a substrate, for example a silicon wafer, which is coated with a light-sensitive layer (photoresist) and arranged in the image plane of the projection system to transfer the mask structure to the photosensitive coating of the substrate.

The cooling device serves in particular to avoid high temperatures and temperature fluctuations of the optical or mechanical component(s) to be cooled. In particular, mirrors of an EUV lithography system (as an example of an optical component) heat up as a result of absorption of the high-energy EUV radiation. The resulting high temperatures and temperature fluctuations in the mirror and the associated thermal deformations of the mirror can lead to wavefront aberrations and thus impair the imaging properties of the mirror. To avoid thermally induced deformations, optical components of the lithography system are actively cooled.

A certain coolant flow rate is required for cooling, which is achieved via a pump system. This leads to dynamic disturbance excitation because each pump generates local pressure fluctuations. These are transmitted through the entire cooling circuit via coolant sound (water sound, longitudinal water sound wave). Furthermore, every change in cross-section and every deflection of the liquid line as well as every installed valve in the cooling circuit can represent a source of interference that causes local pressure fluctuations in the coolant. This type of dynamic disturbance excitation is also called flow-induced or flow-induced vibrations (FIV). The interference excitation is passed on to the cooled component through water sound. This causes the position of the cooled component to deviate from a target position.

The liquid is in particular a cooling liquid such as water.

The cooling device has, for example, a cooling unit for cooling the liquid. The cooling device includes the liquid line and may also have further liquid lines for transporting the liquid. The cooling device further includes one or more pumps for generating a required coolant flow rate of the liquid in the conduit and one or more valves for controlling the cooling flow through the conduit. The cooling device can also be set up to cool several components of the lithography system.

When the cooling device is in operation, the cooling line is, for example, completely filled with the liquid, as seen in the cross section of the cooling line.

The cooling line is, for example, made of metal, such as stainless steel.

The magnetic field generating device is arranged, for example, outside the cooling line. The magnetic field generating device is set up to generate a magnetic field at the location of the float element. By means of the magnetic field generating device, the magnetic float element can be subjected to a force in a non-contact manner.

The axial direction is in particular parallel to a longitudinal direction of the liquid line. The axial direction is in particular parallel to a flow direction of the liquid. In the present case, the axial direction includes both a positive direction (e.g. in the direction of flow) and a negative direction direction (opposite to the direction of flow) along an axis of the liquid line.

The liquid line has, for example, a rotationally symmetrical cross section, e.g. B. a circular cross section, the axis of which defines the axial direction.

The float element floats in particular in the liquid. The float element is spaced, for example, from an inner wall of the liquid line. In other words, the float element does not touch the inner wall of the liquid line, for example.

The pressure-active surface of the float element includes, for example, two opposing pressure-active surfaces. The two opposing pressure-active surfaces are arranged, for example, parallel to one another. The two pressure-active surfaces are, for example, each arranged transversely and/or perpendicular to the axial direction.

In this case, a “pressure-active surface for receiving or releasing pressure” means that the pressure-active surface is suitable for both receiving and releasing pressure. Depending on the application of the cooling device, the pressure-active surface either releases pressure to the liquid or absorbs pressure from the liquid.

The magnetic field generating device has, for example, a permanent magnet with a predetermined polarity for generating a permanent magnetic field. The permanent magnet is, for example, a ring permanent magnet which is arranged in a ring shape around the liquid line. Additionally or instead, the magnetic field generating device can also have an electromagnetic coil and/or be an electromagnetic magnetic field generating device whose magnetic field can be adjusted by supplying power.

According to one embodiment, the magnetic field generating device is set up to apply a magnetic restoring force to the float element in the direction of an axial rest position of the float element.

The float element can be deflected (in the axial direction) by a pressure fluctuation in the liquid. The restoring force generated by the magnetic field generating device then moves the float element back towards the rest position. The float element thus absorbs part of the energy of the pressure fluctuation of the liquid, which is dampened by the pressure fluctuation.

In particular, a pressure surge of liquid arriving at the float element is converted into a force F _p by the pressure-active surface. For the force F _p, F _p = p A, where p is a pressure amplitude of the pressure surge and A is an area of the pressure-active surface. This force F _p causes the float element to move out of its rest position. It is noted that the force acting on the float element due to the constant fluid flow of the liquid in the liquid line does not represent a dynamically changing force. Rather, the float element will find itself in an axial rest position adapted to the flow and move around this rest position due to dynamic pressure surges and variations in the flow rate of the liquid.

A (e.g. constant) magnetic field generated by the magnetic field generating device results in a restoring force which moves the float element back towards the rest position.

In this embodiment, the magnetic field generating device has, for example, a permanent magnet (e.g. ring permanent magnet) and/or generates a permanent magnetic field at the location of the float element.

The axial rest position of the float element is a rest position or undeflected position with respect to a (e.g. permanent) magnetic field generated by the magnetic field generating device.

• eine Induktionsspule zum Induzieren einer Spannung in der Induktionsspule durch eine Bewegung des Schwimmerelements aufgrund einer Druckschwankung der Flüssigkeit, und
• einen elektrisch mit der Induktionsspule verbundenen elektrischen Widerstand zum Umwandeln der induzierten Spannung in thermische Energie.

According to a further embodiment, the magnetic field generating device has:

• an induction coil for inducing a voltage in the induction coil by movement of the float element due to a pressure fluctuation of the liquid, and
• an electrical resistor electrically connected to the induction coil for converting the induced voltage into thermal energy.

This allows additional damping of pressure fluctuations in the liquid in the liquid line to be achieved.

In particular, a pressure fluctuation of the liquid is at least partially converted into kinetic energy of the float element, and furthermore the kinetic energy of the float element is at least partially converted into thermal energy by means of voltage induction and electrical resistance.

The magnetic field generating device has, for example, in addition to the induction coil, a permanent magnet (e.g. ring permanent magnet) for generating the magnetic force. The induction coil is not actively energized in this embodiment. A current flowing in the induction coil is caused merely by the induction of a voltage by the movement of the float element.

According to a further embodiment, the magnetic field generating device has an induction coil for inducing a voltage in the induction coil by a movement of the float element due to a pressure fluctuation of the liquid. In addition, the cooling device has a computing device for determining the pressure fluctuation of the liquid based on the induced voltage.

In this embodiment, the magnetic field generating device can be used together with the float element as a sensor device for measuring pressure fluctuations in the liquid.

For example, an amplitude (e.g. pressure amplitude) of a pressure fluctuation can be detected. For example, a time course of a pressure fluctuation can also be recorded. For example, a pressure fluctuation can be detected with frequency resolution.

In particular, the voltage induced in the induction coil is proportional to the speed of the float element due to a pressure fluctuation of the liquid. By detecting the induced voltage, the speed of the float element can be determined. Furthermore, the force F _p acting on the pressure-active surface can be calculated from the determined speed of the float element. In addition, the following applies: F _p = p A, where A is the known area of the pressure-active surface. A pressure amplitude p of the pressure fluctuation can thus be determined.

In embodiments, the cooling device can alternatively or in addition to an induction coil also have a position sensor for detecting an (axial) position of the float element. This represents an alternative way to determine the pressure of the fluid pressure fluctuation via a movement of the float element. This alternative option is particularly advantageous in the case of low-frequency pressure fluctuations in the liquid.

An example of a position sensor is a Hall sensor. However, other types of position sensors can also be used.

• eine Sensoreinrichtung zum Erfassen einer Druckschwankung der Flüssigkeit, und
• eine Recheneinrichtung zum Ermitteln eines Ansteuersignals basierend auf der erfassten Druckschwankung zum Ansteuern der Magnetfelderzeugungseinrichtung, so dass das Schwimmerelement aufgrund eines von der Magnetfelderzeugungseinrichtung erzeugten Magnetfelds eine Gegendruckschwankung der Flüssigkeit erzeugt, welche die erfasste Druckschwankung dämpft.

According to a further embodiment, the magnetic field generating device is an electromagnetic magnetic field generating device. The cooling device also has:

• a sensor device for detecting a pressure fluctuation of the liquid, and
• a computing device for determining a control signal based on the detected pressure fluctuation for controlling the magnetic field generating device, so that the float element generates a counter-pressure fluctuation of the liquid due to a magnetic field generated by the magnetic field generating device, which dampens the detected pressure fluctuation.

This means that the magnetic field generating device can be used together with the float element to actively dampen pressure fluctuations in the liquid. In particular, the control signal for controlling the magnetic field generating device is determined in such a way that the float element carries out a counter-movement, which leads to the generation of a counter-pressure fluctuation in the liquid on the pressure-active surface of the float element.

Superimposing the pressure fluctuation of the liquid with the counter-pressure fluctuation generated by the float element causes a dampening or cancellation of the original pressure fluctuation of the liquid through destructive interference.

In the electromagnetic magnetic field generating device, a magnetic field is generated by supplying electric current. The control signal controls z. B. the supply of electrical current. The electromagnetic magnetic field generating device in particular has a coil for generating a magnetic field when current flows through the coil.

By appropriately arranging the sensor device and the magnetic field generating device with the float element, sensors and actuators of a control circuit can also be implemented. In this case, the computing device can also include a control unit and can be set up to regulate a pressure of the liquid.

According to a further embodiment, the computing device is set up to determine a control signal that is 180 degrees out of phase with the detected pressure fluctuation.

A control signal that is 180 degrees out of phase can cause destructive interference in the event of a periodic pressure fluctuation. whereby the pressure fluctuation is dampened or eliminated.

According to a further embodiment, the cooling device has a first and a second magnetic force device, each of which comprises a float element and a magnetic field generating device. In addition, the first magnetic force device includes an induction coil and is set up to detect a pressure fluctuation of the liquid based on a voltage induced in the induction coil. Furthermore, the second magnetic force device is an electromagnetic magnetic field generating device and is set up to generate a counter-pressure fluctuation by means of the float element and based on the pressure fluctuation detected by the first magnetic force device.

Consequently, the first magnetic force device functions as a sensor device for detecting a pressure fluctuation of the liquid. In addition, the second magnetic force device functions as an actuator device for actuating the float element based on the detected pressure fluctuation.

According to a further embodiment, the float element, viewed in cross section in the axial direction, has an outer circumference and a flow-through area arranged within the outer circumference for the liquid to flow through.

As a result, the float element, viewed in cross section with respect to the direction of flow, includes, in addition to the pressure-active section with the pressure-active surface at which the liquid encounters resistance, also a (defined) flow area for the liquid to flow through with little or no resistance and/or obstacle.

The pressure-active surface is also arranged within the outer circumference.

Seen in cross section to the axial direction also means seen in the cross section of the liquid line.

According to a further embodiment, the float element comprises a pressure-active section which has the pressure-active surface. The flow area, viewed in cross section in the axial direction, is arranged inside or outside the pressure-active section.

A flow area arranged within the pressure-active section, viewed in cross section in the axial direction, enables the liquid to flow through particularly well and as unhindered as possible.

A flow area arranged outside the pressure-active section, viewed in cross section in the axial direction, enables a centrally arranged pressure-active section. This improves pressure absorption and pressure release through the pressure-sensitive surface of the pressure-active section.

• umfasst das Schwimmerelement einen druckaktiven Abschnitt, welcher die druckaktive Oberfläche aufweist, und ist der druckaktive Abschnitt rotationssymmetrisch zur axialen Richtung angeordnet, und/oder
• ist ein Durchströmbereich des Schwimmerelements zum Durchströmen der Flüssigkeit rotationssymmetrisch zur axialen Richtung angeordnet.

According to another embodiment

• the float element comprises a pressure-active section which has the pressure-active surface, and the pressure-active section is arranged rotationally symmetrically to the axial direction, and/or
• a flow area of the float element for the liquid to flow through is arranged rotationally symmetrically to the axial direction.

According to a further embodiment, the liquid line has an inner wall and at least one projection projecting from the inner wall for axially limiting movement of the float element.

The at least one projection protruding from the inner wall serves as a mechanical end stop. In particular, an axial movement of the float element can be limited in the axial direction due to a pressure fluctuation of the liquid. Consequently, it can be prevented that the float element is completely pushed out of the magnetic field generated by the magnetic field generating device due to fluctuations in the flow rate and/or excessive pressure surges.

The at least one projection is, for example, a projection running around the inner wall of the line. The at least one projection causes, for example, a narrowing of the internal cross-section of the liquid line.

The at least one projection is realized, for example, by a projecting element attached to the inner wall. However, the at least one projection can also be realized, for example, by deforming the material of the liquid line.

For example, the liquid line has two projections projecting from the inner wall. A first of the two projections is arranged in front of the float element, for example, viewed in the flow direction, in order to axially limit a movement of the float element counter to the flow direction of the liquid. Furthermore, there is one second of the two projections, for example viewed in the flow direction, arranged after the float element to axially limit a movement of the float element in the flow direction of the liquid.

According to a further aspect, a lithography system is proposed with a cooling device as described above.

1. a) Erzeugen eines Magnetfelds, und
2. b) Beaufschlagen des Schwimmerelements mit einer axialen magnetischen Kraft durch das erzeugte Magnetfeld.

According to a further aspect, a method for dampening a pressure fluctuation of a liquid in a liquid line of a cooling device of a lithography system is proposed. The liquid is transported along an axial direction of the liquid line. In addition, a magnetic float element with a pressure-active surface for axially receiving or releasing pressure from or to the liquid is arranged within the liquid line. The procedure includes the steps:

1. a) generating a magnetic field, and
2. b) applying an axial magnetic force to the float element through the generated magnetic field.

According to one embodiment of the method, a permanent magnetic field is generated in step a). In addition, in step b), the float element is subjected to a magnetic restoring force in the direction of an axial rest position of the float element.

• Erfassen einer Druckschwankung der Flüssigkeit, und

According to a further embodiment of the method, the magnetic field is generated electromagnetically in step a). The process also has the following steps:

• Detecting a pressure fluctuation of the liquid, and

Determining a control signal based on the detected pressure fluctuation for controlling the magnetic field generating device, so that the float element generates a counter pressure fluctuation of the liquid due to the magnetic field generated by the magnetic field generating device, which dampens the detected pressure fluctuation.

The cooling device is preferably a cooling device of the projection system of the projection exposure system. However, the cooling device can also be a cooling device of a lighting system of the projection exposure system.

In the present case, “on” is not necessarily to be understood as limiting it to exactly 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 to mean that there is a limitation to exactly the number of elements mentioned. Rather, numerical deviations upwards and downwards are possible, unless otherwise stated.

The embodiments and features described for the cooling device apply accordingly to the proposed lithography system and the proposed method and vice versa.

Further possible implementations of the invention also include combinations of features or embodiments described above or below with regard 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 schematischen Meridionalschnitt einer Projektionsbelichtungsanlage für die EUV-Projektionslithographie gemäß einer Ausführungsform;
• 2 zeigt eine Kühlvorrichtung der Projektionsbelichtungsanlage aus 1 gemäß einer Ausführungsform;
• 3 zeigt eine Magnetkraftvorrichtung der Kühlvorrichtung aus 2 gemäß einer Ausführungsform;
• 4 zeigt die Magnetkraftvorrichtung aus 3, wobei ein Schwimmerelement der Magnetkraftvorrichtung aus einer axialen Ruheposition ausgelenkt ist;
• 5 zeigt eine Magnetkraftvorrichtung der Kühlvorrichtung aus 2 gemäß einer weiteren Ausführungsform;
• 6 zeigt eine Magnetkraftvorrichtung der Kühlvorrichtung aus 2 gemäß einer weiteren Ausführungsform;
• 7 zeigt eine Magnetkraftvorrichtung der Kühlvorrichtung aus 2 gemäß einer weiteren Ausführungsform;
• 8 zeigt ein Diagramm einer erfassten Druckschwankung einer Kühlflüssigkeit und eine mithilfe der Magnetkraftvorrichtung aus 7 erzeugten Gegendruckschwankung der Kühlflüssigkeit;
• 9 zeigt eine Magnetkraftvorrichtung der Kühlvorrichtung aus 2 gemäß einer weiteren Ausführungsform;
• 10 zeigt zwei Magnetkraftvorrichtungen der Kühlvorrichtung aus 2 gemäß einer Ausführungsform, wobei eine erste der Magnetkraftvorrichtungen als Sensor und eine zweite als Aktor fungiert;
• 11 zeigt eine Kühlvorrichtung der Projektionsbelichtungsanlage aus 1 gemäß einer weiteren Ausführungsform;
• 12 zeigt eine Magnetkraftvorrichtung der Kühlvorrichtung aus 2 gemäß einer weiteren Ausführungsform, und
• 13 zeigt ein Flussablaufdiagramm eines Verfahrens zum Dämpfen einer Druckschwankung einer Kühlflüssigkeit in einer Flüssigkeitsleitung einer Kühlvorrichtung der Projektionsbelichtungsanlage aus 1 gemäß einer Ausführungsform.

Further advantageous refinements and aspects of the invention are the subject of the subclaims and the exemplary embodiments of the invention described below. The invention is further explained in more detail using preferred embodiments with reference to the accompanying figures.

• 1 shows a schematic meridional section of a projection exposure system for EUV projection lithography according to one embodiment;
• 2 shows a cooling device of the projection exposure system 1 according to one embodiment;
• 3 shows a magnetic force device of the cooling device 2 according to one embodiment;
• 4 shows the magnetic force device 3 , wherein a float element of the magnetic force device is deflected from an axial rest position;
• 5 shows a magnetic force device of the cooling device 2 according to a further embodiment;
• 6 shows a magnetic force device of the cooling device 2 according to a further embodiment;
• 7 shows a magnetic force device of the cooling device 2 according to a further embodiment;
• 8th shows a diagram of a detected pressure fluctuation of a coolant and one using the magnetic force device 7 generated back pressure fluctuation of the coolant;
• 9 shows a magnetic force device of the cooling device 2 according to a further embodiment;
• 10 shows two magnetic force devices of the cooling device 2 according to an embodiment, wherein a first of the magnetic force devices functions as a sensor and a second as an actuator;
• 11 shows a cooling device of the projection exposure system 1 according to a further embodiment;
• 12 shows a magnetic force device of the cooling device 2 according to a further embodiment, and
• 13 shows a flowchart of a method for dampening a pressure fluctuation of a cooling liquid in a liquid line of a cooling device of the projection exposure system 1 according to one embodiment.

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

1 shows an embodiment of a projection exposure system 1 (lithography system), in particular an EUV lithography system. One embodiment of a lighting system 2 of the projection exposure system 1 has, in addition to a light or radiation source 3, lighting optics 4 for illuminating an object field 5 in an object plane 6. In an alternative embodiment, the light source 3 can also be provided as a module separate from the other lighting system 2. In this case, the lighting system 2 does not include the light source 3.

A reticle 7 arranged in the object field 5 is exposed. The reticle 7 is held by a reticle holder 8. The reticle holder 8 can be displaced via a reticle displacement drive 9, in particular in a scanning direction.

In the 1 For explanation purposes, a Cartesian coordinate system with an x-direction x, a y-direction y and a z-direction z is shown. The x-direction x runs perpendicularly into the drawing plane. The y-direction y is horizontal and the z-direction z is vertical. The scanning direction is in the 1 along the y-direction y. The z direction z runs perpendicular to the object plane 6.

The projection exposure system 1 includes projection optics 10. The projection optics 10 is used to image the object field 5 into an image field 11 in an image plane 12. The image plane 12 runs parallel to the object plane 6. Alternatively, an angle other than 0 ° is also between the object plane 6 and the Image level 12 possible.

A structure on the reticle 7 is imaged on a light-sensitive layer of a wafer 13 arranged in the area of the image field 11 in the image plane 12. The wafer 13 is held by a wafer holder 14. The wafer holder 14 can be displaced in particular along the y-direction y via a wafer displacement drive 15. The displacement, on the one hand, of the reticle 7 via the reticle displacement drive 9 and, on the other hand, of the wafer 13 via the wafer displacement drive 15 can take place in synchronization with one another.

The light source 3 is an EUV radiation source. The light source 3 emits in particular EUV radiation 16, which is also referred to below as useful radiation, illumination radiation or illumination light. The useful radiation 16 in particular has a wavelength in the range between 5 nm and 30 nm. The light source 3 can be a plasma source, for example an LPP source (Laser Produced Plasma, plasma generated with the help of a laser) or a DPP source (Gas Discharged Produced Plasma). It can also be a synchrotron-based radiation source. The light source 3 can be a free electron laser (FEL).

The illumination radiation 16, which emanates from the light source 3, is focused by a collector 17. The collector 17 can be a collector with one or more ellipsoidal and/or hyperboloid reflection surfaces. The at least one reflection surface of the collector 17 can be in grazing incidence (GI), i.e. with angles of incidence greater than 45 °, or in normal incidence (English: Normal Incidence, NI), i.e. with angles of incidence smaller than 45 ° , with the lighting radiation 16 are applied. The collector 17 can be structured and/or coated on the one hand to optimize its reflectivity for the useful radiation and on the other hand to suppress false light.

After the collector 17, the illumination radiation 16 propagates through an intermediate focus in an intermediate focus plane 18. The intermediate focus plane 18 can provide a separation between a radiation source module, comprising the light source 3 and the collector 17, and the lighting optics 4 represent.

The lighting optics 4 comprises a deflection mirror 19 and, downstream of it in the beam path, a first facet mirror 20. The deflection mirror 19 can be a flat deflection mirror or alternatively a mirror with an effect that influences the bundle beyond the pure deflection effect. Alternatively or additionally, the deflection mirror 19 can be designed as a spectral filter which separates a useful light wavelength of the illumination radiation 16 from false light of a wavelength that deviates from this. If the first facet mirror 20 is arranged in a plane of the illumination optics 4, which is optically conjugate to the object plane 6 as a field plane, it is also referred to as a field facet mirror. The first facet mirror 20 includes a large number of individual first facets 21, which can also be referred to as field facets. Of these first facets 21 are in the 1 just a few are shown as examples.

The first facets 21 can be designed as macroscopic facets, in particular as rectangular facets or as facets with an arcuate or part-circular edge contour. The first facets 21 can be designed as flat facets or alternatively as convex or concave curved facets.

Like, for example, from the DE 10 2008 009 600 A1 is known, the first facets 21 themselves can also each be composed of a large number of individual mirrors, in particular a large number of micromirrors. The first facet mirror 20 can in particular be designed as a microelectromechanical system (MEMS system). For details see the DE 10 2008 009 600 A1 referred.

Between the collector 17 and the deflection mirror 19, the illumination radiation 16 runs horizontally, i.e. along the y-direction y.

A second facet mirror 22 is located downstream of the first facet mirror 20 in the beam path of the illumination optics 4. If the second facet mirror 22 is arranged in a pupil plane of the illumination optics 4, it is also referred to as a pupil facet mirror. The second facet mirror 22 can also be arranged at a distance from a pupil plane of the lighting optics 4. In this case, the combination of the first facet mirror 20 and the second facet mirror 22 is also referred to as a specular reflector. Specular reflectors are known from US 2006/0132747 A1 , the EP 1 614 008 B1 and the US 6,573,978 .

The second facet mirror 22 comprises a plurality of second facets 23. In the case of a pupil facet mirror, the second facets 23 are also referred to as pupil facets.

The second facets 23 can also be macroscopic facets, which can have, for example, round, rectangular or even hexagonal edges, or alternatively they can be facets composed of micromirrors. In this regard, reference is also made to the DE 10 2008 009 600 A1 referred.

The second facets 23 can have flat or alternatively convex or concave curved reflection surfaces.

The lighting optics 4 thus forms a double faceted system. This basic principle is also known as the honeycomb condenser (Fly's Eye Integrator).

It may be advantageous not to arrange the second facet mirror 22 exactly in a plane that is optically conjugate to a pupil plane of the projection optics 10. In particular, the second facet mirror 22 can be arranged tilted relative to a pupil plane of the projection optics 10, as is the case, for example, in FIG DE 10 2017 220 586 A1 is described.

With the help of the second facet mirror 22, the individual first facets 21 are imaged into the object field 5. The second facet mirror 22 is the last beam-forming mirror or actually the last mirror for the illumination radiation 16 in the beam path in front of the object field 5.

In a further embodiment of the illumination optics 4, not shown, transmission optics can be arranged in the beam path between the second facet mirror 22 and the object field 5, which contributes in particular to the imaging of the first facets 21 into the object field 5. The transmission optics can have exactly one mirror, but alternatively also two or more mirrors, which are arranged one behind the other in the beam path of the lighting optics 4. The transmission optics can in particular include one or two mirrors for perpendicular incidence (NI mirror, normal incidence mirror) and/or one or two mirrors for grazing incidence (GI mirror, grazing incidence mirror).

The lighting optics 4 has the version in the 1 is shown, after the collector 17 exactly three mirrors, namely the deflection mirror 19, the first facet mirror 20 and the second facet mirror 22.

In a further embodiment of the lighting optics 4, the deflection mirror 19 can also be omitted, so that the lighting optics 4 can then have exactly two mirrors after the collector 17, namely the first facet mirror 20 and the second facet mirror 22.

The imaging of the first facets 21 into the object plane 6 by means of the second facets 23 or with the second facets 23 and a transmission optics is generally only an approximate image.

The projection optics 10 comprises a plurality of mirrors Mi, which are numbered consecutively according to their arrangement in the beam path of the projection exposure system 1.

At the one in the 1 In the example shown, the projection optics 10 includes six mirrors M1 to M6. Alternatives with four, eight, ten, twelve or another number of mirrors Mi are also possible. The projection optics 10 is a double obscured optics. The penultimate mirror M5 and the last mirror M6 each have a passage opening for the illumination radiation 16. The projection optics 10 has an image-side numerical aperture that is larger than 0.5 and which can also be larger than 0.6 and, for example, 0.7 or can be 0.75.

Reflection surfaces of the mirrors Mi can be designed as free-form surfaces without an axis of rotational symmetry. Alternatively, the reflection surfaces of the mirrors Mi can be designed as aspherical surfaces with exactly one axis of rotational symmetry of the reflection surface shape. The mirrors Mi, like the mirrors of the lighting optics 4, can have highly reflective coatings for the lighting radiation 16. These coatings can be designed as multilayer coatings, in particular with alternating layers of molybdenum and silicon.

The projection optics 10 has a large object image offset in the y direction y between a y coordinate of a center of the object field 5 and a y coordinate of the center of the image field 11. This object image offset in the y direction y can be in be approximately as large as a z-distance between the object plane 6 and the image plane 12.

The projection optics 10 can in particular be anamorphic. In particular, it has different imaging scales Bx, By in the x and y directions x, y. The two imaging scales Bx, By of the projection optics 10 are preferably (βx, βy) = (+/- 0.25, +/- 0.125). A positive image scale β means an image without image reversal. A negative sign for the image scale B means an image with image reversal.

The projection optics 10 thus leads to a reduction in size in the x direction x, that is to say in the direction perpendicular to the scanning direction, in a ratio of 4:1.

The projection optics 10 leads to a reduction of 8:1 in the y direction y, that is to say in the scanning direction.

Other image scales are also possible. Image scales of the same sign and absolutely the same in the x and y directions x, y, for example with absolute values of 0.125 or 0.25, are also possible.

The number of intermediate image planes in the x and y directions x, y in the beam path between the object field 5 and the image field 11 can be the same or, depending on the design of the projection optics 10, can be different. Examples of projection optics with different numbers of such intermediate images in the x and y directions x, y are known from US 2018/0074303 A1 .

One of the second facets 23 is assigned to exactly one of the first facets 21 to form an illumination channel for illuminating the object field 5. This can in particular result in lighting based on Köhler's principle. The far field is broken down into a large number of object fields 5 using the first facets 21. The first facets 21 generate a plurality of images of the intermediate focus on the second facets 23 assigned to them.

The first facets 21 are each imaged onto the reticle 7 by an assigned second facet 23, superimposed on one another, in order to illuminate the object field 5. The illumination of the object field 5 is in particular as homogeneous as possible. It preferably has a uniformity error of less than 2%.

Field uniformity can be achieved by overlaying different lighting channels.

By arranging the second facets 23, the illumination of the entrance pupil of the projection optics 10 can be geometrically defined. By selecting the illumination channels, in particular the subset of the second facets 23 that guide light, the intensity distribution in the entrance pupil of the projection optics 10 can be adjusted. This intensity distribution is also referred to as the lighting setting or lighting pupil filling.

A likewise preferred pupil uniformity in the area of defined illuminated sections of an illumination pupil of the illumination optics 4 can be achieved by redistributing the illumination channels.

Further aspects and details of the illumination of the object field 5 and in particular the entrance pupil of the projection optics 10 are described below.

The projection optics 10 can in particular have a homocentric entrance pupil. This can be accessible. It can also be inaccessible.

The entrance pupil of the projection optics 10 cannot regularly be illuminated precisely with the second facet mirror 22. When imaging the projection optics 10, which images the center of the second facet mirror 22 telecentrically onto the wafer 13, the aperture rays often do not intersect at a single point. However, an area can be found in which the pairwise distance of the aperture beams becomes minimal. This surface represents the entrance pupil or a surface conjugate to it in local space. In particular, this surface shows a finite curvature.

It may be that the projection optics have 10 different positions of the entrance pupil for the tangential and sagittal beam paths. In this case, an imaging element, in particular an optical component of the transmission optics, should be provided between the second facet mirror 22 and the reticle 7. With the help of this optical element, the different positions of the tangential entrance pupil and the sagittal entrance pupil can be taken into account.

At the in the 1 As shown in the arrangement of the components of the illumination optics 4, the second facet mirror 22 is arranged in a surface conjugate to the entrance pupil of the projection optics 10. The first facet mirror 20 is tilted relative to the object plane 6. The first facet mirror 20 is arranged tilted to an arrangement plane that is defined by the deflection mirror 19. The first facet mirror 20 is arranged tilted to an arrangement plane that is defined by the second facet mirror 22.

2 shows a cooling device 100 for the projection exposure system 1 1 according to one embodiment.

The cooling device 100 is set up to cool an optical or mechanical component 102 of the projection exposure system 1. An example of an optical component 102 is a mirror of the projection exposure system 1 (lithography system), in particular the projection optics 10 1 . The optical component 102 is, for example, one of the mirrors M1 - M6. An example of a mechanical component 102 is a sensor frame (not shown) of the projection exposure system 1.

A sensor frame includes e.g. B. a sensor device for measuring a current position of an optical component 102 of the lithography system 1 relative to the sensor frame. The sensor frame is, for example, mounted in a vibration-decoupled manner with respect to a support frame of the optical component. The sensor device includes e.g. B. one or more sensors, such as interferometers and / or other measuring devices for detecting a position of the optical component. The optical component can, for example, have reflector elements for reflecting light emitted by the sensors (e.g. laser light).

The cooling device 100 includes a cooling pipe 104 for transporting a cooling liquid 106 ( 2 ).

The cooling device 100 includes, for example, a cooling unit 108 for cooling the cooling liquid 102. The cooling device 100 also includes one or more pumps 110 for generating a required coolant flow rate of the cooling liquid 106. The cooling device 100 may also include one or more valves 112 for controlling the cooling flow.

Pumps 110 of the cooling device 100 cause local pressure fluctuations in the liquid 106, thereby generating a dynamic disturbance excitation. These pressure fluctuations are transmitted via longitudinal water sound waves through the entire cooling circuit 114 to the component 102 to be cooled. Furthermore, cross-sectional changes and deflections 116 of the liquid line 104 as well as valves 112 of the cooling device 100 can also represent a source of interference that causes local pressure fluctuations in the liquid 106. Such acoustic interference is passed on to the component 102 to be cooled by water sound. This can lead to an undesirable change in position of the component 102 to be cooled, which worsens the imaging properties of the projection exposure system 1.

To suppress pressure fluctuations in the cooling liquid 106, the cooling device 100 has one or more magnetic force devices 118.

With the help of the magnetic force device 118, pressure fluctuations 120 ( 4 ) of the liquid 106 can be passively and/or actively damped.

3 shows a partial section of the cooling device 100 2 . In 3 a section of the cooling line 104 can be seen. Furthermore, a magnetic force device 118 according to an embodiment is shown.

The cooling line 104 or the section of the cooling line 104 serves to transport the cooling liquid 106 along an axial direction A of the cooling line 104.

The magnetic force device 118 includes a magnetic float element 122. The magnetic float element 122 is arranged within the cooling line 104. The float element 122 has a first pressure-active surface 124 and a second pressure-active surface 126. The pressure-active surfaces 124, 126 can each absorb pressure from the cooling liquid 106 and release pressure to the cooling liquid 106. The pressure absorption and pressure release by the pressure-active surfaces 124, 126 takes place in particular in the axial direction A. The float element 122 and its pressure-active surfaces 124, 126 are in direct contact with the coolant 106 and can therefore directly absorb or generate coolant sound. The first and second pressure-active surfaces 124, 126 in 3 are arranged opposite and parallel to each other.

The magnetic force device 118 also includes a magnetic field generating device 128 for axially applying a magnetic force F _B to the float element 122. With the help of the magnetic field generating device 128, the float element 122 can be subjected to force without contact.

In the example of 3 the magnetic field generating device 128 is, for example, a ring permanent magnet which is arranged around the cooling line 104 and generates a constant magnetic field B at the location of the float element 122.

In 3 the float element 122 is shown in an axial rest position P ₀ , which is defined by the magnetic field B generated by the magnetic field generating device 128.

In 4 a deflection of the float element 122 from its rest position P ₀ due to a pressure fluctuation 120 is illustrated. In this case, a magnetic restoring force F _R acts on the float element 122 in the direction of the rest position P ₀ .

Since the pressure-active surface 124 of the float element 122 absorbs at least part of the pressure of the pressure fluctuation 120 and converts it into kinetic energy, the pressure fluctuation 120 can be dampened. This allows a change in position of a component 102 to be cooled (caused by a pressure fluctuation 120 of the cooling liquid 106) 2 ) can be reduced or avoided. In particular, a pressure fluctuation 120 can be dampened before it reaches the component 102 to be cooled.

Furthermore, it can be advantageous if the magnetic force device 118 is arranged in the flow direction R of the cooling liquid 106 (e.g. directly) in front of the component 102 to be cooled, as in 2 shown.

5 shows a partial section of a cooling device 200 according to a further embodiment. In 5 a portion of a cooling line 204 and a magnetic force device 218 of the cooling device 200 are shown.

The magnetic force device 218 in 5 includes how the magnetic force device 118 in 3 , a magnetic float element 222 with a first and a second pressure-active surface 224, 226.

Furthermore, the magnetic force device 218 in 5 a magnetic field generating device 228. In the case of the magnetic field generating device 228, as in the case of the magnetic field generating device 128 in 3 , a permanent magnet 250 (e.g. ring permanent magnet) is provided. In addition, the magnetic field generating device 228 includes an induction coil 252, 254. In the example of 5 Two ring coils 252, 254 are provided, which surround the liquid line 204 in a ring shape. The induction coils 252, 254 are not actively powered (ie by a power source) in this embodiment.

In addition, the magnetic force device 218 has an electrical resistance 256 that is electrically connected to the induction coil 252, 254.

If the float element 222 moves due to a pressure fluctuation 120 ( 4 ) of the cooling liquid 106 moves in the axial direction A, then a voltage is induced in the induction coil 252, 254. The electrical resistance 256 (e.g. shunt resistor) connected in parallel allows the induced voltage to be converted into thermal energy. This allows additional damping of pressure fluctuations 120 of the coolant 106 to be achieved.

6 shows a partial section of a cooling device 300 according to a further embodiment. In 6 a portion of a cooling line 304 and a magnetic force device 318 of the cooling device 300 are shown.

The magnetic force device 318 in 6 includes how the magnetic force device 118 in 3 , a magnetic float element 322 with a first and a second pressure-active surface 324, 326.

Furthermore, the magnetic force device 318 in 6 a magnetic field generating device 328. In the case of the magnetic field generating device 328, as in the case of the magnetic field generating device 228 in 5 , a permanent magnet 350 (e.g. ring permanent magnet) and an induction coil 352, 354 are provided. Also in the example of 6 Two ring coils 352, 354 are provided, which surround the liquid line 304. The induction coils 352, 354 are also not actively supplied with power (ie by a power source) in this embodiment.

In addition, the magnetic force device 318 has a voltage measuring device 356 for detecting a voltage U induced in the induction coil 352, 354 (e.g. the two toroidal coils 352, 354). The voltage measuring device 356 is connected to a computing device 358 of the cooling device 300 for data transmission. The computing device 358 is set up to determine a pressure fluctuation 120 of the cooling liquid 106 based on the detected induced voltage U.

By providing the voltage measuring device 356 and the computing device 358, the magnetic force device 318 can be used not only to dampen a pressure fluctuation 120 of the cooling liquid 106, but also as a sensor device for detecting a pressure fluctuation 120 of the cooling liquid 106.

For example, an amplitude (e.g. pressure amplitude) of a pressure fluctuation 120 can be detected. For example, a time course and/or a frequency of a pressure fluctuation 120 can be recorded. For example, a pressure fluctuation 120 can be detected with frequency resolution.

7 shows a partial section of a cooling device 400 according to a further embodiment. In 7 a portion of a cooling line 404 and a magnetic force device 418 of the cooling device 400 are shown. On the left side of 7 the cooling line 404 with the float element 422 is shown in a longitudinal cross section (cross section along the axial direction A). On the right side of 7 the float element 422 is shown in a cross section along line CC perpendicular to the longitudinal direction.

The magnetic force device 418 in 7 includes how the magnetic force device 118 in 3 , a magnetic float element 422 with a first and a second pressure-active surface 424, 426.

Furthermore, the magnetic force device 418 in 7 a magnetic field generating device 428. The magnetic field generating device 428 is an electromagnetic magnetic field generating device 428 that is actively energized. The magnetic field generating device 428 includes, like the magnetic field generating device 228 in 5 , a permanent magnet 450 (e.g. ring permanent magnet) and a coil 452, 454. Also in the example of 7 Two ring coils 452, 454 are provided, which surround the liquid line 404 in a ring. Furthermore, a controllable power supply unit (not shown) is provided to supply the coils 452, 454 with power.

The cooling device 400 also includes a sensor device 456 for detecting a pressure fluctuation 120 of the cooling liquid 106. The sensor device 456 is in 7 only shown schematically. The sensor device 456 can be used, for example, by the in 6 shown, acting as a sensor device magnetic force device 318 can be realized. However, the sensor device 456 can also be another type of sensor device for detecting a pressure fluctuation 120 of the coolant 106.

The cooling device 400 further comprises a computing device 458 for determining a control signal D for controlling the magnetic field generating device 428. The computing device 458 receives information E (signal E) from the sensor device 456 regarding the detected pressure fluctuation and determines the control signal D based on the transmitted information E.

In particular, the computing device 458 is set up to determine the control signal D for controlling the magnetic field generating device 428 in such a way that the magnetic field generating device 428 generates a magnetic field B, which causes an axial movement of the float element 422, which in turn leads to the float element 422 moving through its axial Movement generates a counter-pressure fluctuation of the cooling liquid 106 in the axial direction A, which dampens and/or cancels the detected pressure fluctuation 120 through destructive interference.

In 8th an example of a time course of a pressure P over time t of a periodic pressure fluctuation 120 'of the cooling liquid 106 is illustrated. In this example, the computing device 458 can determine the control signal D for controlling the magnetic field generating device 428 as a control signal D that is 180 degrees out of phase. Controlled in this way, the magnetic field generating device 428 will actuate the float element 422 accordingly, so that the float element produces a counter-pressure fluctuation 460 that is 180 degrees out of phase ( 8th ) generated.

In 7 Further optional features of the cooling device 400 and the magnetic force device 418 are shown that are applied to each of the cooling devices 100, 200, 300, 400, 500, 600, 700 and magnetic force devices 118, 218, 318, 418, 518, 618, 718 described herein can.

As in 7 As shown, the liquid line 404 (and any other liquid line described herein) may optionally include an inner wall 462 and at least one projection 464, 466 projecting from the inner wall 462 for axially limiting movement of the float element 422. In 7 Two projections 464, 466 are shown as examples. Viewed in the flow direction R of the liquid 106, a first projection 464 is arranged in front of the float element 422 and a second projection 466 is arranged after the float element 422. The projections 464, 466 in 7 are each designed, for example, as projections running around the inner wall 462 of the line 404.

As in 7 shown, the float element 422 (and any other float element described herein), viewed in cross section to the axial direction A, may have an outer circumference 468 and a flow region 470 arranged within the outer circumference 468 for the cooling liquid 106 to flow through. In particular, the float element 422, as shown on the right side of 7 can be seen, a pressure-active section 472 with the pressure-active surfaces 424, 426 and the flow area 470. The pressure-active section 472, the pressure-active surfaces 424, 426 and the flow area 470 are further arranged, in particular, rotationally symmetrically to the axial direction A. Furthermore, in the example of 7 , the flow area 470, seen in cross section to the axial direction A, is arranged within the pressure-active section 472. In other examples (see 9 ), however, a flow area 570 can also be arranged outside a pressure-active section 572, seen in cross section to the axial direction A.

As in 7 As shown, the magnetic float element 422 (and any other float element described herein) may include one or more permanent magnets, such as one or more ring permanent magnets. In 7 Examples of two ring permanent magnets 474, 476 are shown. Furthermore, in 7 an exemplary polarity of the ring permanent magnets 474, 476 is illustrated, which together with a suitable polarity of the permanent magnet 450 corresponds to that in connection with 4 described restoring force F _R leads in the direction of the axial rest position P ₀ . In the illustrated polarities, “N” denotes a magnetic north pole and “S” denotes a magnetic south pole.

9 shows a partial section of a cooling device 500 according to a further embodiment. In 9 a portion of a cooling line 504 and a magnetic force device 518 of the cooling device 500 are shown. On the left side of 9 the cooling line 504 with the float element 522 is shown in a longitudinal cross section (cross section along the axial direction A). On the right side of 9 the float element 522 is shown in a cross section along line FF perpendicular to the longitudinal direction.

The magnetic force device 518 in 9 includes how the magnetic force device 118 in 3 , a magnetic float element 522 with a first and a second pressure-active surface 524, 526.

Furthermore, the magnetic force device includes 518 in 9 a magnetic field generating device 528. The magnetic field generating device 528 can be set up for passive damping of pressure fluctuations 120 or can also be an electromagnetic magnetic field generating device 428, which is set up for actively damping pressure fluctuations 120. The magnetic field generating device 528 includes, like the magnetic field generating device 228 in 5 , a permanent magnet 550 (e.g. ring permanent magnet) and a coil 552, 554. Also in the example of 9 Two ring coils 552, 554 are provided, which surround the liquid line 504 in a ring.

Furthermore, a controllable power supply unit (not shown) can be provided to supply the coils 552, 554 with power.

In 9 Another embodiment of the float element 522 is illustrated, which can be applied to any float element described herein. The float element 522 has a pressure-active section 572 with two pressure-active surfaces 524 and 526. Furthermore, the float element 522 has a flow area 570 for the cooling liquid 106 to flow through. In this embodiment, the pressure-active section 572 is arranged within the flow area 570. The float element 522 also has a plurality of radial struts 574, some of which are in 9 are provided with a reference number. The flow area 570 is further arranged within an outer circumference 568 of the float element 522.

10 shows a partial section of a cooling device 600 according to a further embodiment. The cooling device 600 has first and second magnetic force devices 618, 618'. Each of the first and second magnetic force devices 618, 618' includes a magnetic float element 622, 622' floating within a corresponding portion 604a, 604b of a liquid line 604 of the cooling device 600. The float elements 622, 622' may be configured like any float element described herein.

Each of the first and second magnetic force devices 618, 618' further comprises a magnetic field generating device 628, 628' with a permanent magnet 650, 650' and a coil 652, 652', 654, 654'.

The first magnetic force device 618 functions as a sensor device, similar to the magnetic force device 318 in 6 . The second magnetic force device 618' is an electromagnetic magnetic force device that functions as an actuator device, similar to the magnetic force device 418 in 7 .

Furthermore, the cooling device comprises 600 in 10 a computing device 658 similar to the computing device 458 in 7 . In particular, the computing device 658 is set up to receive information E (signal E) in relation to a pressure fluctuation 120 of the cooling liquid 106 detected by the first magnetic force device 618. Furthermore, the computing device 658 is set up to determine a control signal D for controlling the second magnetic force device 618 ', in particular for controlling the magnetic field generating device 628 ' of the second magnetic force device 618 ', based on the information E received in relation to the detected pressure fluctuation.

In particular, the computing device 658 is set up to determine the control signal D for controlling the magnetic field generating device 628 'in such a way that the magnetic field generating device 628' generates a magnetic field B, which causes an axial movement of the float element 622', which in turn leads to the float element 622 'through its axial movement, a counter-pressure fluctuation 460 of the cooling liquid 106 is generated in the axial direction A, which dampens and/or cancels the detected pressure fluctuation 120 through destructive interference.

The combination of the first and second magnetic force devices 618, 618' and the computing device 658 can also be referred to as a damper system 660 for dampening pressure fluctuations.

As in 11 illustrated, a cooling device 700 can optionally also be set up to cool a plurality of optical or mechanical components 102, 102', 102" of the lithography system 1. Optionally, a cooling device 700 can also additionally or instead also have a plurality of magnetic force devices 718, 718' and/or a plurality of damper systems 760 , 760', 760'', 760''' each with one or more magnetic force devices 718, 718'.

Furthermore, there are 11 a cooling unit 708 (similar to the cooling unit 108 in 2 ), a pump 710 (similar to the pump 110 in 2 ) and valves 712 (similar to valve 112 in 2 ) of the cooling device 700 is shown.

12 shows a partial section of a cooling device 800 according to a further embodiment. In 12 a portion of a cooling line 804 and a magnetic force device 818 of the cooling device 800 are shown. On the left side of 12 the cooling line 804 with the float element 822 is shown in a longitudinal cross section (cross section along the axial direction A). On the right side of 12 the float element 822 is shown in a cross section along line GG perpendicular to the longitudinal direction.

The magnetic force device 818 in 12 includes, similar to the magnetic force device 118 in 3 , a magnetic float element 822 with a first and a second pressure-active surface 824, 826.

Furthermore, the magnetic force device comprises 818 in 12 a magnetic field generating device 828. The magnetic field generating device 828 can be set up for passive damping of pressure fluctuations 120 or can also be an electromagnetic magnetic field generating device 828, which is set up for actively damping pressure fluctuations 120. The magnetic field generating device 828 includes, similar to the magnetic field generating device 228 in 5 , a permanent magnet 850 (e.g. Ringperma nentmagnet) and a coil 852, 854. In the example of 12 Two permanent magnets 850 (e.g. two ring permanent magnets 850 surrounding the liquid line 804 in a ring) are provided. Furthermore, in the example of 12 Two ring coils 852, 854 are provided, which surround the liquid line 804 in a ring. Furthermore, a controllable power supply unit (not shown) can be provided to supply the coils 852, 854 with power.

The polarity (north pole N and south pole S) of the permanent magnets 850 differs, for example. B. from the polarity of the permanent magnet 450 in 7 . In particular, a south pole-north pole direction of the permanent magnet is 450 in 7 aligned radially (ie perpendicular to the axial direction A), while a south pole-north pole direction of the permanent magnets 850 in 12 is aligned parallel to the axial direction.

In 12 Another embodiment of the float element 822 is also illustrated, which can be applied to any float element described herein. The float element 822 has a pressure-active section 872 with two pressure-active surfaces 824 and 826. Furthermore, the float element 822 has a flow area 870 for the cooling liquid 106 to flow through. In this embodiment, the flow area 870 is arranged within the (annular) pressure-active section 872.

In addition, the float element 822 has a permanent magnet 874 (e.g. ring permanent magnet 874) with a polarity N, S as indicated. In the example of 12 the pressure-active section 872 is formed by the permanent magnet 874. In other examples, a permanent magnet 874 may also fill only a portion of the pressure-active portion 872. The magnetic polarity (north pole N and south pole S) of the permanent magnet 874 points, similar to the permanent magnets 474, 476 in 7 , a south pole-north pole direction aligned parallel to the axial direction A.

The arrangement of the magnets 850, 874 of the magnetic field generating device 828 results in a deflection of the float element 822 from an axial rest position (P ₀ in 4 ), similar to e.g. B. in the magnetic field generating device 428, to a restoring force F _R in the direction of the axial rest position.

The following is with reference to 13 a method for dampening a pressure fluctuation 120 of a liquid 106 in a liquid line 104 of a cooling device 100 of a lithography system 1 is described. The liquid 106 (e.g. coolant) is transported in an axial direction A of the liquid line 104. Furthermore, a magnetic float element 122 with a pressure-active surface 124, 126 for axially receiving or releasing pressure from or to the liquid 106 is arranged within the liquid line 104.

In a first step S1 of the method, a magnetic field B is generated.

In a second step S2 of the method, the float element 122 is subjected to an axial magnetic force F _B by the generated magnetic field.

In a first variant, the method can optionally be used to passively dampen a pressure fluctuation 120 of a liquid 106. For this purpose, a permanent magnetic field B can be generated in step S1. In addition, in step S2, the float element 122 can be subjected to a magnetic restoring force F _R in the direction of an axial rest position P ₀ of the float element 122 by the permanent magnetic field B.

In a second variant, the method can optionally also be used to actively dampen a pressure fluctuation 120 of a liquid 106.

In a first step S 1 'of the method according to the second variant, a pressure fluctuation 120 of the liquid 106 is detected.

In a second step S2' of the method according to the second variant, a control signal D is determined based on the detected pressure fluctuation 120 for controlling a magnetic field generating device 418. The control signal D is determined in such a way that a float element 422 generates a counter-pressure fluctuation 460 of the liquid 106 based on the magnetic field generated by the magnetic field generating device 418, which dampens the detected pressure fluctuation 120.

In a third step S3' of the method according to the second variant, a magnetic field B is generated in accordance with the control signal D by the magnetic field generating device 418.

In a fourth step S4 'of the method according to the second variant, the float element 422 is subjected to an axial magnetic force F _B by the generated magnetic field B, so that the float element 422 generates the counter-pressure fluctuation 460 in the liquid 106. A superposition of the detected pressure fluctuation 120 with the counterpressure fluctuation 460 leads to destructive interference in the sense of active vibration suppression.

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

REFERENCE SYMBOL LIST

1

Projection exposure system

2

Lighting system

3

light source

4

Illumination optics

5

Object field

6

Object level

7

Reticule

8th

Reticle holder

9

Reticle displacement drive

10

Projection optics

11

Image field

12

Image plane

13

wafers

14

wafer holder

15

Wafer displacement drive

16

Illumination radiation

17

collector

18

Intermediate focal plane

19

Deflecting mirror

20

first facet mirror

21

first facet

22

second facet mirror

23

second facet

100

Cooling device

102, 102', 102"

component

104

Fluid line

106

liquid

108

Cooling unit

110

pump

112

Valve

114

Circulation

116

Deflection

118

Magnetic force device

120, 120'

pressure fluctuation

122

Float element

124

surface

126

surface

128

Magnetic field generating device

200

Cooling device

204

Cooling line

218

Magnetic force device

222

Float element

224

surface

226

surface

228

Magnetic field generating device

250

Permanent magnet

252

Kitchen sink

254

Kitchen sink

256

Resistance

300

Cooling device

304

Cooling line

318

Magnetic force device

322

Float element

324

surface

326

surface

328

Magnetic field generating device

350

Permanent magnet

352

Kitchen sink

354

Kitchen sink

356

Voltmeter

358

Computing facility

400

Cooling device

404

Cooling line

418

Magnetic force device

422

Float element

424

surface

426

surface

428

Magnetic field generating device

450

Permanent magnet

452

Kitchen sink

454

Kitchen sink

456

Sensor device

458

Computing facility

460

Back pressure fluctuation

462

Wall

464

head Start

466

head Start

468

Scope

470

flow area

472

Section

474

magnet

476

magnet

500

Cooling device

504

Cooling line

518

Magnetic force device

522

Float element

524

surface

526

surface

528

Magnetic field generating device

550

Permanent magnet

552

Kitchen sink

554

Kitchen sink

568

Scope

570

flow area

572

Section

574

strut

600

Cooling device

604

Cooling line

604a, 604b

Section

618, 618'

Magnetic force device

622, 622'

Float element

628, 628'

Magnetic field generating device

650,650'

Permanent magnet

652, 652'

Kitchen sink

654, 654'

Kitchen sink

658

Computing facility

660

Damper system

700

Cooling device

708

Cooling unit

710

pump

712

Valve

718, 718'

Magnetic force device

760, 760'

Damper system

760'', 760'''

Damper system

800

Cooling device

804

Cooling line

818

Magnetic force device

822

Float element

824

surface

826

surface

828

Magnetic field generating device

850

Permanent magnet

852

Kitchen sink

854

Kitchen sink

870

flow area

872

Section

874

magnet

A

Direction

b

Magnetic field

D

signal

E

signal

FB

Power

FR

Power

M1-M6

Mirror

N

North Pole

P

Pressure

P0

position

R

Direction

S

South Pole

S1-S4

Procedural steps

U

Tension

QUOTES INCLUDED IN THE DESCRIPTION

This list of 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.

Cited patent literature

• DE 102008009600 A1 [0087, 0091]
• US 20060132747 A1 [0089]
• EP 1614008 B1 [0089]
• US 6573978 [0089]
• DE 102017220586 A1 [0094]
• US 20180074303 A1 [0108]

Claims (15)

Cooling device (100) for a lithography system (1), comprising: a liquid line (104) for transporting a liquid (106) along an axial direction (A) of the liquid line (104), a magnetic float element (122) arranged within the liquid line (104). ) with a pressure-active surface (124, 126) for axially receiving or releasing pressure (P) from or to the liquid (106), and a magnetic field generating device (128) for axially applying a magnetic force to the float element (122) ( _FB ). cooling device Claim 1 , wherein the magnetic field generating device (128) is set up to apply a magnetic restoring force (F _R ) to the float element (122) in the direction of an axial rest position (P ₀ ) of the float element (122). cooling device Claim 2 , wherein the magnetic field generating device (228) comprises: an induction coil (252, 254) for inducing a voltage in the induction coil (252, 254) by a movement of the float element (222) due to a pressure fluctuation (120) of the liquid (106), and a electrical resistance (256) electrically connected to the induction coil (252, 254) for converting the induced voltage into thermal energy. cooling device Claim 2 or 3 , wherein the magnetic field generating device (328) has an induction coil (352, 354) for inducing a voltage (U) in the induction coil (352, 354) by a movement of the float element (322) due to a pressure fluctuation (120) of the liquid (106), and the cooling device (300) has a computing device (358) for determining the pressure fluctuation (120) of the liquid (106) based on the induced voltage (U). Cooling device according to one of the Claims 1 - 4 , wherein the magnetic field generating device (428) is an electromagnetic magnetic field generating device (428), and the cooling device (400) has: a sensor device (456) for detecting a pressure fluctuation (120) of the liquid (106), and a computing device (458) for determining a Control signal (D) based on the detected pressure fluctuation (120) for controlling the magnetic field generating device (428), so that the float element 422 generates a counter pressure fluctuation (460) of the liquid (106) due to a magnetic field (B) generated by the magnetic field generating device (428), which dampens the detected pressure fluctuation (120). cooling device Claim 5 , wherein the computing device (458) is set up to determine a control signal (D) that is 180 degrees out of phase with the detected pressure fluctuation (120). Cooling device according to one of the Claims 1 - 6 , comprising a first and a second magnetic force device (618, 618'), each of which comprises a float element (622, 622') and a magnetic field generating device (628, 628'), the first magnetic force device (618) having an induction coil (652, 654) and is set up to detect a pressure fluctuation (120) of the liquid (106) based on a voltage induced in the induction coil (652, 654), and the second magnetic force device (618 ') comprises an electromagnetic magnetic field generating device (628') and for generating a Counterpressure fluctuation (460) is set up by means of the float element (622 ') and based on the pressure fluctuation (120) detected by the first magnetic force device (618). Cooling device according to one of the Claims 1 - 7 , wherein the float element (422), seen in cross section in the axial direction (A), has an outer circumference (468) and a flow area (470) arranged within the outer circumference (468) for the liquid (107) to flow through. cooling device Claim 8 , wherein the float element (422, 522) comprises a pressure-active section (472, 572), which has the pressure-active surface (424, 426, 524, 526), and the flow area (470, 570), in cross section to the axial direction ( A) seen, is arranged inside or outside the pressure-active section (472, 572). Cooling device according to one of the Claims 1 - 9 , wherein the float element (422) comprises a pressure-active section (472), which has the pressure-active surface (424, 426), and the pressure-active section (472) is arranged rotationally symmetrically to the axial direction (A), and / or a flow area ( 470) of the float element (422) for the liquid (106) to flow through is arranged rotationally symmetrical to the axial direction (A). Cooling device according to one of the Claims 1 - 10 , wherein the liquid line (404) has an interior wall (462) and at least one projection (464, 466) projecting from the inner wall (462) for axially limiting a movement of the float element (422). Lithography system (1) with a cooling device (100) according to one of Claims 1 until 11 . Method for dampening a pressure fluctuation (120) of a liquid (106) in a liquid line (104) of a cooling device (100) of a lithography system (1), wherein the liquid (106) is transported along an axial direction (A) of the liquid line (104). , a magnetic float element (122) with a pressure-active surface (124, 126) for axially receiving or releasing pressure (P) from or to the liquid (106) is arranged within the liquid line (104), and the method has the steps comprises: a) generating (S1, S3') a magnetic field (B), and b) applying (S2, S4') to the float element (122) with an axial magnetic force ( _FB ) through the generated magnetic field (B). Procedure according to Claim 13 , wherein in step a) a permanent magnetic field (B) is generated (S1), and the float element (122) in step b) with a magnetic restoring force (F _R ) in the direction of an axial rest position (P ₀ ) of the float element (122) is applied (S2). Procedure according to Claim 13 , wherein the magnetic field (B) is generated electromagnetically in step a) (S3'), and the method has the steps: detecting (S1') a pressure fluctuation (120) of the liquid (106), and determining (S2') a control signal (D) based on the detected pressure fluctuation (120) to control the magnetic field generating device (428), so that the float element (422) generates a counter pressure fluctuation (460) of the liquid (106) due to the magnetic field (B) generated by the magnetic field generating device (428). , which dampens the detected pressure fluctuation (120).

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