Device and method for pre-aging an optical element for semiconductor lithography

Abstract

Device (1) for pre-aging an optical element for semiconductor lithography comprising: - a first heating device (2) for applying a first heating power (H1) to a surface (4) of an optical element (5) to be heated, and - a second heating device (3) for applying a second heating power (H2) to a surface (4) of an optical element (5) to be heated, - wherein the second heating device (3) is configured to move the second heating power (H2) along a surface (4) of an optical element (5) to be heated, characterized in that the first heating device (2) for applying a first heating power (H1) is configured with a heating power density that varies over a surface (4) of an optical element (5) to be heated, and that the first heating device (2) is configured such that the first heating power (H1) can be applied to the majority of the surface (4) of an optical element (5) to be heated.

Description

[0001] The invention relates to a device for pre-aging an optical element for semiconductor lithography, comprising: a first heating device for applying a first heating power to a surface of an optical element to be heated, and a second heating device for applying a second heating power to a surface of an optical element to be heated, wherein the second heating device is designed to move the second heating power along a surface of an optical element to be heated.

[0002] The invention further relates to a method for pre-aging an optical element for semiconductor lithography, comprising the following steps: a) providing an optical element, wherein the optical element comprises a surface to be heated, b) providing a device for pre-aging an optical element for semiconductor lithography, in particular according to one of claims 1 to 5, wherein the device for pre-aging an optical element for semiconductor lithography comprises a first heating device for applying a first heating power to the surface of the optical element to be heated and a second heating device for applying a second heating power to the surface of the optical element to be heated, and wherein the second heating device is designed to move the second heating power along the surface of the optical element to be heated,c) heating the surface of the optical element to be heated by applying the first heating power of the first heating device to the surface of the optical element to be heated and by applying the second heating power of the second heating device to the surface of the optical element to be heated.

[0003] Projection exposure systems for semiconductor lithography, especially microlithography for the EUV wavelength range of 1 nm - 120 nm, rely on the reflective optical elements used to image a mask into an image plane to have a high degree of surface shape accuracy. Likewise, masks as reflective optical elements for the EUV wavelength range should have a high degree of surface shape accuracy, as their replacement has a significant impact on the operating costs of a projection exposure system.

[0004] To ensure the high accuracy of the surface shape of optical elements, various correction methods are known. Some of the correction methods are based on locally densifying the substrate material of optical elements through irradiation. This results in a change in the surface shape of the optical element near the irradiated areas. Other methods are based on direct surface ablation of the optical element. Still others of the mentioned methods utilize the thermal or electrical deformability of materials to impose spatially extensive surface shape changes on the optical elements.

[0005] DE 10 2011084117 A1 and WO 2011 / 020655 A1 disclose methods for protecting the reflective optical element from long-term compaction (hereinafter referred to as "compacting") on the order of several vol. % or aging of the substrate material due to EUV radiation, in addition to correcting the surface shape. For this purpose, the surface of the reflective optical element is homogeneously exposed to radiation, thereby compacting it and / or coating it with a protective layer. Both methods prevent the EUV radiation from penetrating the substrate material. This can prevent long-term, unacceptable surface deformations caused by compaction of the material by the EUV radiation.

[0006] The reason for the compaction or aging of substrate materials, such as Zerodur® from Schott AG or ULE® from Corning Inc., which contain more than 40 vol.% SiO2, is assumed to be a thermodynamically non-equilibrium state frozen at the high manufacturing temperatures of the substrate material, which transitions to a thermodynamic ground state upon EUV irradiation. Consistent with this hypothesis, SiO2 coatings can be produced that do not exhibit such compaction, since, with the appropriately selected coating method, these layers are produced at significantly lower temperatures than the substrate material.

[0007] The compaction decreases over time, which in turn changes the surface shape. This decrease in compaction, which will also be referred to as decompaction, is presumably due to a relaxation of the defect states created in the material by irradiation. The changes in surface shape caused over time by decompaction during operation at the customer's site can be anticipated by annealing the optical element during production. This minimizes any remaining decompaction and the resulting changes to the surface during operation at the customer's site. To do this, the optical element is heated to temperatures above normal operating temperature for an extended period of time, which accelerates and thus anticipates the decompaction that occurs over time.

[0008] A disadvantage of the known tempering methods and tempering devices, such as those known from DE 10 2020 203 750 A1, is that during tempering or heating with a surface heating device, a heating power is applied to the optical element to be heated which has a constant heating power density across the surface of the optical element to be heated. This is disadvantageous because different sections of the optical element release heat at different rates. The different rates of heat release are caused, among other things, by counter-cooling of the optical element and by inhomogeneous heat dissipation through the optical element outside the surface to be heated. This leads to temperature fluctuations on the optical element, in particular on the surface of the optical element to be heated.Such temperature fluctuations can be either local temperature fluctuations, also known as temperature inhomogeneity, across the optical element—i.e., differences in temperature depending on the respective location of the optical element. They can also be temporal temperature fluctuations—i.e., changes in temperature, for example, at a specific location on the optical element, over time.

[0009] A further, second heating device, which can move a second heating power along the surface to be heated, must therefore apply a heating power locally to the optical element in an increased manner, in particular in a scanning manner, in order to reduce, in particular, local and / or temporal temperature fluctuations on the surface of the optical element to be heated. However, in the case of a laser as the second heating device, the speed at which the second heating device can move the heating power along the surface of the optical element to be heated is limited, among other things, by the technical limitations of the laser. The second heating device may therefore not be able to compensate for a temperature fluctuation on the surface of the optical element to be heated quickly enough.

[0010] Another disadvantage of the known annealing methods and devices is that the second heating device is not optimally moved along the surface of the optical element to be heated. This circumstance also contributes to the fact that temperature fluctuations on the surface of the optical element to be heated are not compensated for sufficiently quickly.

[0011] Furthermore, it must be considered that the temperature fluctuations, especially the temporal temperature fluctuations, on the surface of the optical element to be heated must be kept below a certain limit. With regard to temporal temperature fluctuations, both the amplitude and the number of fluctuations must be kept below a certain limit. Excessively strong temporal temperature fluctuations, especially excessive amplitude and the number of fluctuations, can lead to damage to the optical element, for example, to coatings on the optical element. Therefore, the first heating device and the second heating device must be optimally coordinated with each other.

[0012] When designing a corresponding device and method, various aspects must be balanced against each other and appropriately combined. These aspects include, among others: - the permissible local temperature fluctuation, - the permissible temperature fluctuation over time, particularly influenced by the cooling and / or heating of the optical element, - the absolute temperatures achievable, in particular on average on the surface of the optical element to be heated, and - the reproducibility, in particular the reproducibility of the application of the first heating power, the application of the second heating power and / or the cooling of the optical element.

[0013] The invention is therefore based on the object of designing and developing the device mentioned at the outset and described in more detail above, as well as the method mentioned at the outset and described in more detail above, in such a way that the temperature fluctuations on the surface of the optical element to be heated are reduced in a structurally simple manner.

[0014] This object is achieved in a device according to the preamble of patent claim 1 in that the first heating device is designed to apply a first heating power with a heating power density that varies across a surface of an optical element to be heated. As a result, a heating power density profile adapted to the varying heat emission levels of different sections of the optical element can be applied directly to the surface to be heated, and temperature fluctuations can be reduced. Thus, in turn, the heating power density with which the second heating power of the second heating device heats the optical element can be reduced and / or the speed at which the second heating device moves the second heating power along the surface of the optical element to be heated can be reduced. This enables the use of a lower-power, more cost-effective, and structurally simpler second heating device.

[0015] In this case, the heating power density refers to the heating power per heated area. A heating power density that varies across a surface of an optical element to be heated means that the heating power density of a heating power applied by a heating device has different values ​​at different locations on the surface of an optical element to be heated.

[0016] The first heating device is advantageously designed such that the first heating power can be applied to the majority, in particular to substantially the entire, surface of an optical element to be heated. This allows the largest possible area to be heated simultaneously with the first heating device.

[0017] The second heating device is advantageously designed to move the second heating element along paths along a surface of an optical element to be heated. This simplifies the defined heating of the surface to be heated.

[0018] The first heating device and / or the second heating device can also be configured such that the first heating power of the first heating device and / or the second heating power of the second heating device can be varied. This allows the heating power to be adapted to the respective optical element to be heated.

[0019] The total heating output, i.e., the sum of the first heating output and the second heating output, is preferably in the range of a few kW. For example, the total heating output is intended to be less than and / or equal to 10 kW. The total heating output can be divided between the first heating output and the second heating output depending on the specific case and / or optical element.

[0020] A first embodiment of the device is characterized in that the first heating device comprises at least one mirror and that, preferably, the at least one mirror is designed to vary the heating power density of the first heating power to be applied across the surface of an optical element to be heated. The at least one mirror can redirect the heating power, in particular onto a surface of an optical element to be heated. By means of a correspondingly designed mirror, a heating power density profile adapted to the different heat emission levels of different sections of the optical element can also be impressed on the first heating power of the first heating device in a structurally simple manner. The at least one mirror is preferably individually adapted to an optical element to be heated.Advantageously, the first heating device comprises at least two mirrors, wherein the at least two mirrors are preferably each individually adapted to an optical element to be heated. This allows a separate, individually adapted mirror to be provided for different optical elements, thus providing an individually adapted heating power density profile for different optical elements.

[0021] In the present case, varying the heating power density is understood to mean, in particular, that a heating power impinging on the mirror has different heating power densities at different locations on a surface of an optical element to be heated after impinging on the mirror.

[0022] According to one embodiment of the device, the device for pre-aging an optical element for semiconductor lithography comprises: a changing device for changing the at least one mirror. This allows the at least one mirror to be changed and, if necessary, replaced with another mirror. Therefore, the changing device is preferably provided for changing the at least two mirrors. The changing device can be configured as a tool turret, wherein preferably the at least one mirror, in particular the at least two mirrors, are accommodated as tools in the tool turret. This enables rapid changing of the at least one mirror.

[0023] A further embodiment of the device provides that the second heating device comprises a laser. A laser allows the second heating power to be applied very precisely to the surface of an optical element to be heated, thus eliminating temperature fluctuations locally and in a targeted manner.

[0024] According to one embodiment of the device, the device for pre-aging an optical element for semiconductor lithography comprises: a controller for controlling and / or regulating the first heating device and / or the second heating device, and / or a sensor for detecting a temperature at at least one location on a surface of an optical element to be heated. The controller and the sensor make it easier to keep temperature fluctuations on the surface of the optical element to be heated as low as possible using the first heating device and / or second heating devices. The controller can also be designed in particular to control and / or regulate the first heating power, the second heating power, the heating power density of the first heating power, the heating power density of the second heating power, and / or the temperature on a surface of an optical element to be heated.Control and / or regulation of these parameters can be achieved, among other things, by changing the power of the first heating device and / or the power of the second heating device, by changing the speed at which the second heating device moves the second heating power, preferably in paths, by changing the distance between the paths along which the second heating device moves the second heating power, by changing the beam diameter of the second heating power and / or by changing the area that is simultaneously heated by the second heating power of the second heating device. In the case of a change in the beam diameter of the second heating power, this change can be achieved in the second heating device comprising a laser, for example, by varying the laser beam diameter.The sensor is preferably configured to detect temperatures up to at least 130 °C, preferably up to at least 200 °C.

[0025] The object mentioned above is further achieved in a method according to the preamble of patent claim 6 in that, in step c), the second heating device moves the second heating power in parallel and / or concentric paths shaped according to the circumferential shape of the surface of the optical element to be heated, preferably in circular paths, in particular in concentric circular paths, along the surface of the optical element to be heated. Since the sections of the optical element which emit heat with different intensity and / or speed are generally shaped according to the circumferential shape of the surface of the optical element to be heated, the surface of the optical element can be heated in a targeted manner in the respective sections, thus reducing temperature fluctuations on the surface of the optical element to be heated.A concentric arrangement, in turn, simplifies a uniform arrangement of the tracks and thus contributes to more uniform heating of the surface of the optical element to be heated. This also contributes to reducing temperature fluctuations on the surface of the optical element to be heated.

[0026] When configured as parallel tracks, the tracks preferably extend at least partially in a straight line, in particular essentially completely in a straight line. However, the configuration as tracks shaped and / or concentrically shaped according to the circumferential shape of the surface of the optical element to be heated is preferred over the configuration as parallel tracks.

[0027] In the present case, tracks shaped according to the circumferential shape of the surface of the optical element to be heated are understood to mean that the tracks have, at least in sections, the same shape, in particular substantially the same shape, as the circumferential shape of the surface of the optical element to be heated. However, the track is optionally reduced in size, preferably to scale, compared to the circumference of the surface of the optical element to be heated. If the surface of the optical element to be heated is circular or elliptical, for example, the tracks are also substantially circular or elliptical.

[0028] The device provided in step b) is preferably a device according to one of claims 1 to 5. The explanations explained for the device can therefore be applied to the method. Alternatively or additionally, the explanations regarding the method can be applied to the device.

[0029] The paths in which the second heating device moves the second heating power along the surface of the optical element to be heated can be designed as closed paths.

[0030] According to a first embodiment of the method, in step c), the first heating device applies the first heating power with a heating power density that varies across the surface of the optical element to be heated. This allows a heating power density profile adapted to the varying heat dissipation of different sections of the optical element to be applied directly to the surface to be heated, and temperature fluctuations can be reduced. Thus, the heating power density with which the second heating power of the second heating device heats the optical element can be reduced and / or the speed at which the second heating device moves the second heating power along the surface of the optical element to be heated can be reduced. This enables the use of a lower-power, more cost-effective, and structurally simpler second heating device.The heating power density of the first heating power can be at least 100 W / m. 2 and / or up to 10 kW / m 2 However, it is also conceivable that the heat output density of the first heating output can be up to 100 kW / m 2 or more if applicable.

[0031] It can be provided that in step c), the first heating device applies the first heating power to the majority, in particular to substantially the entire area, of the surface of the optical element to be heated. This allows the largest possible area to be heated simultaneously with the first heating device.

[0032] One embodiment of the method is characterized in that in step c) the first heating device and / or the second heating device is configured, in particular controlled and / or regulated, in such a way that the total heating power density applied at at least one point on the surface of the optical element to be heated, in particular at substantially every point on the surface of the optical element to be heated, is below a predetermined value and / or the temperature at at least one point on the surface of the optical element to be heated, in particular at substantially every point on the surface of the optical element to be heated, is within a predetermined temperature range. By controlling or regulating the applied total heating power density below a predetermined value, temperature peaks on the surface of the optical element to be heated are avoided.Temperature peaks can lead to uneven aging and potentially damage to the optical element. By controlling or regulating the temperature within a specified temperature range, temperature fluctuations can be reduced and temperature peaks avoided.

[0033] The total heating power density is the combined heating power densities of the first heating power and the second heating power for the respective location on the surface of the optical element to be heated.

[0034] According to a further embodiment of the method, it is provided that the surface of the optical element to be heated comprises at least a first zone and a second zone, preferably at least a first zone, a second zone and a third zone, and that, preferably, in step c) the second heating device in the first zone applies the second heating power to the surface of the optical element to be heated with a different heating power density than in the second zone, preferably in the first zone applies the second heating power to the surface of the optical element to be heated with a different heating power density than in the second zone and / or than in the third zone.By applying the second heating power with a different heating power density depending on the zones, the second heating power can be applied with a heating power density that is adapted to the different heat dissipation rates of different sections of the surface of the optical element to be heated. This can reduce temperature fluctuations on the surface of the optical element. The zones therefore preferably correspond to sections of the optical element that dissipate heat at different rates. Furthermore, the zones are each zones to be heated. Furthermore, more than at least two, preferably more than at least three, zones can be provided.

[0035] Preferably, the first zone is arranged adjacent to the second zone, the second zone is arranged adjacent to the third zone, and / or the second zone is arranged adjacent between the first zone and the second zone. The first zone is advantageously arranged at and / or along the outer edge of the surface of the optical element to be heated. The third zone can, in turn, be arranged around the center and / or in the center of the surface of the optical element to be heated.

[0036] Furthermore, it can be provided that in step c), the second heating device in the first zone applies the second heating power to the surface of the optical element to be heated at a higher heating power density than in the second zone, and / or the second heating device in the third zone applies the second heating power to the surface of the optical element to be heated at a higher heating power density than in the second zone. This allows a heating power with a higher heating power density to be specifically applied to the sections of the optical element that dissipate heat more quickly. This also allows temperature fluctuations to be reduced.

[0037] One embodiment of the method is characterized in that in step c) the speed at which the second heating device moves the second heating power in paths is predetermined depending on the zone, in step c) the distance between the paths along which the second heating device moves the second heating power is predetermined depending on the zone, in step c) the power of the second heating device is predetermined depending on the zone, in step c) the beam diameter of the second heating power is predetermined depending on the zone and / or in step c) the area that is heated simultaneously by the second heating power of the second heating device is predetermined depending on the zone. As a result, the second heating power, in particular the second heating power density, can be optimally adapted to the respective zone, in particular location, of the surface of the optical element to be heated.In addition, the heating power density can be reduced or increased in certain zones without having to change the heating power provided by the second heating power. This allows a less powerful, less expensive, and structurally simpler second heating device to be used, and also simplifies the control of the second heating power. The specification can in each case be an open-loop and / or closed-loop control. The specification, in particular open-loop and / or closed-loop control, is carried out in particular as a function of the zone currently heated by the second heating device. Since the first heating power and / or second heating power in the present device and the present method are preferably applied in the form of electromagnetic radiation, the beam diameter of the second heating power is the beam diameter of the electromagnetic radiation which the second heating power applies.

[0038] By reducing the speed, for example, the heating power density is increased because the heating power acts on the same spot for longer. Increasing the speed in turn leads to a reduction in the heating power density because the same spot is heated for a shorter period of time. Reducing the distance between the tracks leads to an increase in the heating power density because one and the same spot may be exposed to heating power along a number of different tracks. Increasing the distance in turn leads to a reduction in the heating power density for the corresponding spot because the spot is exposed to heating power less frequently. By increasing the area that is heated by one heating power at the same time or by increasing the beam diameter of the second heating power, the heating power density can be reduced because the heating power is distributed over a larger area.Reducing this area, in turn, leads to a higher heating power density. By increasing or decreasing the power of the second heating device, for example, the heating power density can be increased or decreased accordingly without having to adjust the other parameters.

[0039] A change in the area that is heated simultaneously by the second heating power of the second heating device can be achieved for a second heating device comprising a laser, for example, by changing the laser beam diameter.

[0040] The invention is explained in more detail below with reference to a drawing that represents only a preferred embodiment. The drawing shows: Fig. 1 A device according to the invention for pre-aging an optical element for semiconductor lithography in a front view, Fig. 2 an optical element in a plan view, and Fig. 3 the optical element Fig. 2 in another top view.

[0041] In Fig. 1A shows a front view of an apparatus according to the invention for pre-aging an optical element for semiconductor lithography 1. The apparatus 1 comprises a first heating device 2 and a second heating device 3. By means of the two heating devices 2, 3, a surface 4 of an optical element 5 to be heated is subjected to a first heating power H1 of the first heating device 2 and a second heating power H2 of the second heating device 3, and is thereby heated. The optical element 5 is held in a workpiece holder 6, wherein the workpiece holder 6 can comprise a cooling device for cooling the optical element 5. The workpiece holder 6 can be a component of the apparatus for pre-aging an optical element for semiconductor lithography 1.

[0042] In the present case, the first heating device 2 comprises a first radiation source 7, a collimator 8, at least two mirrors 9, and a changing device 10 for changing the at least two mirrors 9. The first radiation source 7 generates the first heating power H1. To adjust the first heating power H1, the power of the first heating device 2, in particular the power of the first radiation source 7, can be adjusted, among other things.

[0043] In the illustrated device for pre-aging an optical element for semiconductor lithography 1, the mirrors 9 are mounted on the changing device 10, wherein the changing device 10 is configured in the form of a tool turret. The mirrors 9 can be moved and changed by the changing device 10, in particular by a rotational movement of the changing device 10, and can thereby be moved into or out of the beam path of the first heating device 2.

[0044] The mirrors 9 are so-called free-form mirrors and are each individually adapted to an optical element 5 to be heated. The mirrors 9 are designed to vary the heating power density of the first heating power H1 to be applied across the surface 4 of the optical element 5 to be heated. The mirror 9 thus changes the radiation generated by the first radiation source 7 or first heating power H1 in such a way that the first heating power H1 applied by the first heating device 2 has different heating power densities at different points on the surface 4 of the optical element 5 to be heated. In this way, sections of the optical element 5 that cool down more quickly can be heated more intensely with the first heating device 2, and sections of the optical element 5 that cool down less quickly can be heated less intensely. By changing the mirrors 9, the best possible mirror 9 can be selected for the respective surface to be heated oroptical element 5 to be pre-aged is provided.

[0045] The second heating device 3 in turn comprises a second radiation source 11, wherein the second radiation source 11 is a laser in this case. The second radiation source 11 generates the second heating power H2. During the heating of the surface 4 of the optical element 5 to be heated, the second heating power H2 is moved along the surface 4 of the optical element 5 to be heated. The movement can be achieved by moving, in particular by pivoting and / or shifting, the second heating power H2, preferably the radiation forming the second heating power H2. Alternatively or additionally, the second heating device 3, in particular the second radiation source 11, can also be moved, preferably pivoted and / or shifted. The second heating power H2 moves in a scanning manner along the surface 4 of the optical element 5 to be heated.In this way, temperature fluctuations occurring on the surface 4 of the optical element 5 to be heated can be compensated locally.

[0046] In Fig. 2 shows an optical element 5 in a plan view. The optical element 5 corresponds to the Fig. 1 and is to be heated or pre-aged. It is shown that the surface 4 of the optical element 5 to be heated comprises three zones Z1, Z2, Z3. The three zones Z1, Z2, Z3 essentially correspond to sections of the optical element 5 which emit heat at different rates. By dividing the optical element 5 into the different zones Z1, Z2, Z3, the device for pre-aging an optical element for semiconductor lithography 1 during heating of the optical element 5, in particular the second heating device 3 during heating of the optical element 5, can be controlled and / or regulated in a targeted manner and adapted to the requirements of the sections of the optical element 5 which emit heat at different rates.

[0047] A first zone Z1 is arranged at the outer edge of the surface 4 of the optical element 5 to be heated. A third zone Z3 is arranged in the center and around the center of the surface 4 of the optical element 5 to be heated, and a second zone Z2 is arranged between the first zone Z1 and the third zone Z3. Since heat is generally dissipated more quickly at the outer edge of the surface 4 of the optical element 5 to be heated, and thus in the first zone Z1, than in the second zone Z2, the device for pre-aging an optical element for semiconductor lithography 1 is preferably controlled and / or regulated such that the heating power density of the second heating power H2 is higher in the first zone Z1 than in the second zone Z2.Likewise, in the middle of the surface 4 of the optical element 5 to be heated, and thus in the third zone Z3, heat is generally released more quickly than in the second zone Z2 due to cooling of the optical element 5, preferably by the cooling device of the workpiece holder 6. Therefore, the device for pre-aging an optical element for semiconductor lithography 1 is preferably controlled and / or regulated in such a way that the heating power density of the second heating power H2 is higher in the third zone Z3 than in the second zone Z2. The heating power density of the second heating power H2 can be controlled and / or regulated accordingly by adjusting a large number of parameters. This will be discussed in more detail below. Fig. 3 will be discussed.

[0048] In Fig. 3 is the optical element 5 made of Fig.2 in a further plan view. For better understanding, paths B are shown schematically on the surface 4 of the optical element 5 to be heated. The paths B correspond to the paths B in which the second heating device 3 moves the second heating power H2 along the surface 4 of the optical element 5 to be heated. The paths B are shaped according to the circumferential shape of the surface 4 of the optical element 5 to be heated. The surface 4 of the optical element 5 to be heated and the optical element 5 itself are circular in the present case, so that the paths B are also circular. The paths B are arranged concentrically to one another and spaced from one another in order to achieve sufficient coverage of the surface 4 of the optical element 5 to be heated. The paths B are also each designed as closed paths B.Furthermore, the tracks B are arranged distributed along substantially the entire surface 4 of the optical element 5 to be heated.

[0049] For controlling and / or regulating the heating power density of the second heating power H2, the distances between the tracks B can be reduced or increased. Alternatively or additionally, the speed at which the second heating device 3 moves the second heating power H2 in tracks B can also be reduced or increased. Alternatively or additionally, the laser beam diameter of the laser of the second heating device 3 can be reduced or increased, thus changing the area of ​​the surface 4 to be heated simultaneously. Furthermore, further parameters can be adjusted to achieve controlling and / or regulating the heating power density of the second heating power H2; for example, the power of the second heating device 2, in particular the power of the second radiation source 11, can be adjusted. List of reference symbols 1 Device for pre-aging an optical element for semiconductor lithography 2 first heating device 3 second heating device 4 Surface to be heated 5 optical element 6 Workpiece holder 7 first radiation source 8 Collimation 9 mirrors 10 Changing device 11 second radiation source B track H1 first heating output H2 second heating output Z1 first zone Z2 second zone Z3 third zone QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This 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

[0000] DE 10 2011084117 A1

[0005] WO 2011 / 020655 A1

[0005] DE 10 2020 203 750 A1

[0008]

Claims

[1] Device for pre-aging an optical element for semiconductor lithography (1) comprising: - a first heating device (2) for applying a first heating power (H1) to a surface (4) of an optical element (5) to be heated, and - a second heating device (3) for applying a second heating power (H2) to a surface (4) of an optical element (5) to be heated, - wherein the second heating device (3) is designed to move the second heating power (H2) along a surface (4) of an optical element (5) to be heated, characterized by that the first heating device (2) is designed to apply a first heating power (H1) with a heating power density that varies over a surface (4) of an optical element (5) to be heated. [2] Device (1) according to claim 1 characterized bythat the first heating device (2) comprises at least one mirror (9) and that, preferably, the at least one mirror (9) is designed to vary the heating power density of the first heating power (H1) to be applied over the surface (4) of an optical element (5) to be heated. [3] Device (1) according to claim 2 characterized by that the device for pre-aging an optical element for semiconductor lithography (1) comprises: - a changing device (10) for changing the at least one mirror (9). [4] Device (1) according to one of claims 1 to 3 characterized by that the second heating device (3) comprises a laser. [5] Device (1) according to one of claims 1 to 4 characterized by that the device for pre-aging an optical element for semiconductor lithography (1) comprises: - a controller for controlling and / or regulating the first heating device (2) and / or the second heating device (3), and / or - a sensor for detecting a temperature at at least one point of a surface (4) to be heated of an optical element (5). [6] Method for pre-aging an optical element (5) for semiconductor lithography, comprising the following steps: a) providing an optical element (5), - wherein the optical element (5) comprises a surface (4) to be heated, b) providing a device for pre-aging an optical element for semiconductor lithography (1), in particular according to one of claims 1 to 5, - wherein the device for pre-aging an optical element for semiconductor lithography (1) comprises a first heating device (2) for applying a first heating power (H1) to the surface (4) of the optical element (5) to be heated and a second heating device (3) for applying a second heating power (H2) to the surface (4) of the optical element (5) to be heated, and - wherein the second heating device (3) is designed to move the second heating power (H2) along the surface (4) of the optical element (5) to be heated, c) heating the surface (4) of the optical element (5) to be heated by applying the first heating power (H1) of the first heating device (2) to the surface (4) of the optical element (5) to be heated and by applying the second heating power (H2) of the second heating device (3) to the surface (4) of the optical element (5) to be heated, characterized byin that in step c) the second heating device (3) moves the second heating power (H2) in parallel and / or concentric paths (B) shaped according to the circumferential shape of the surface (4) of the optical element (5) to be heated, preferably in circular paths (B), in particular in concentric circular paths (B), along the surface (4) of the optical element (5) to be heated. [7] Method according to claim 6 characterized by that in step c) the first heating device (2) applies the first heating power (H1) with a heating power density varying over the surface (4) of the optical element (5) to be heated. [8] Method according to claim 6 or claim 7 characterized byin step c) the first heating device (2) and / or the second heating device (3) is / are set up, in particular controlled and / or regulated, in such a way that the total heating power density applied at at least one point on the surface (4) of the optical element (5) to be heated, in particular at substantially every point on the surface (4) of the optical element (5) to be heated, is below a predetermined value and / or the temperature at at least one point on the surface (4) of the optical element (5) to be heated, in particular at substantially every point on the surface (4) of the optical element (5) to be heated, is within a predetermined temperature range. [9] Method according to one of claims 6 to 8 characterized bythat the surface to be heated (4) of the optical element (5) comprises at least a first zone (Z1) and a second zone (Z2), preferably at least a first zone (Z1), a second zone (Z2) and a third zone (Z3), and that, preferably, in step c), the second heating device (3) in the first zone (Z1) applies the second heating power (H2) to the surface to be heated (4) of the optical element (5) with a different heating power density than in the second zone (Z2), preferably in the first zone (Z1) applies the second heating power (H2) to the surface to be heated (4) of the optical element (5) with a different heating power density than in the second zone (Z2) and / or than in the third zone (Z3). [10] Method according to claim 9 characterized bythat in step c) the speed at which the second heating device (3) moves the second heating power (H2) in paths (B) is predetermined as a function of the zone (Z1, Z2, Z3), in step c) the distance between the paths (B) along which the second heating device (3) moves the second heating power (H2) is predetermined as a function of the zone (Z1, Z2, Z3), in step c) the power of the second heating device (3) is predetermined as a function of the zone (Z1, Z2, Z3), in step c) the beam diameter of the second heating power (H2) is predetermined as a function of the zone (Z1, Z2, Z3) and / or in step c) the area which is heated simultaneously by the second heating power (H2) of the second heating device (3) is predetermined as a function of the zone (Z1, Z2, Z3).

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