Lithography apparatus and illumination uniformity correction method

Abstract

The lithographic apparatus comprises an illumination system configured to condition a radiation beam, and a uniformity correction system configured to condition an intensity profile of the radiation beam, The lithographic apparatus comprises a control system configured to control the uniformity correction system based at least in part on a thermal condition criterion indicative of a thermal condition of a part of the lithographic apparatus.

Description

Technical Field

[0001] [Cross-reference to Related Applications] This application claims the priority of European Patent Application No. 21164836.5 filed on March 25, 2021, the entire content of which is incorporated herein by reference.

[0002] The present invention relates to a lithographic apparatus comprising an illumination uniformity correction system and a related method. The present invention generally relates to lithography, and more particularly to a system and method for compensating for uniformity drift caused by thermal effects.

Background Art

[0003] A lithographic apparatus is a machine configured to apply a desired pattern onto a substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). A lithographic apparatus can project the pattern of a patterning device (e.g., a reticle or a mask) onto a layer of radiation-sensitive material (resist) provided on a substrate.

[0004] To project a pattern onto a substrate, a lithographic apparatus may use electromagnetic radiation. The minimum size of the features that can be formed on the substrate is determined by the wavelength of this radiation. A lithographic apparatus using extreme ultraviolet (EUV) radiation having a wavelength within the range of 4 - 20 nm, for example 6.7 nm or 13.5 nm, can be used to form smaller features on a substrate than a lithographic apparatus using radiation having a wavelength of 193 nm.

[0005] A lithography apparatus typically includes an illumination system configured to adjust the radiation generated by a radiation source before it enters a patterning device. The illumination system can modify one or more properties of the radiation, such as polarization and / or illumination mode. The illumination system may include a uniformity correction system configured to correct or reduce non-uniformity present in the radiation, such as intensity non-uniformity. The uniformity correction system may use, for example, actuated fingers inserted into the edge of the radiation beam to correct for intensity variations.

[0006] To ensure good imaging quality on the patterning device and substrate, controlled uniformity of the radiated beam is maintained. That is, the radiated beam before it is reflected from or transmitted through the patterning device may have a non-uniform intensity profile. For the entire lithography process, it is desirable that the radiated beam be controlled to be at least somewhat uniform. Uniformity may refer to a constant intensity across the entire radiated beam, or it may refer to the ability to control the illumination to achieve a target illumination uniformity. The target illumination uniformity can have a flat or non-flat profile. The patterning device imparts a pattern to the radiated beam, which is then imaged onto the substrate. The image quality of this projected radiated beam is affected by the uniformity of the radiated beam. System drift correction is typically performed once per substrate lot. A substrate lot consists of, for example, 20-30 substrates, or, for example, 25 substrates. Known uniformity correction systems and methods are used during the approximately 300 ms to 600 ms interval between exposures of subsequent substrate lots.

[0007] It is desirable to provide uniformity correction systems and methods that reduce non-uniformity of the radiated beam relative to a target illumination profile while minimizing adverse effects on substrate throughput. An object of this disclosure is to provide lithography apparatus and methods for illumination uniformity correction that address one or more problems, whether specified herein or elsewhere, or provide at least a useful alternative. [Overview of the project] [Problems that the invention aims to solve]

[0008] The object of this disclosure is to provide an improved concept of a lithography apparatus and method for correcting illumination uniformity. This object is achieved by the subject matter of the independent claim. Further embodiments of the improved concept are the subject matter of the dependent claim. [Means for solving the problem]

[0009] According to a first aspect of the present disclosure, a lithography apparatus is provided comprising an illumination system configured to adjust a radiation beam. The lithography apparatus comprises a uniformity correction system configured to adjust the intensity profile of the radiation beam. The lithography apparatus comprises a control system configured to control the uniformity correction system at least in part on a thermal state criterion indicating a part of the thermal state of the lithography apparatus.

[0010] A lithography apparatus may comprise a support device, a substrate table, and a projection system. The support device may be configured to hold a patterning device configured to give a pattern to the cross-section of the radiation beam to form a patterned radiation beam. The substrate table may be configured to hold a substrate. The projection system may be configured to project the patterned radiation beam onto a target portion of the substrate.

[0011] The illumination system may be configured to adjust the radiation generated by the radiation source before the radiation beam is incident on the patterning device. The illumination system may be configured to modify one or more properties of the radiation beam, such as the polarization and / or illumination mode of the radiation beam.

[0012] A uniformity correction system may form part of an illumination system. The uniformity correction system may be configured to correct or reduce non-uniformity present in the radiant beam, such as intensity non-uniformity. The uniformity correction system may include fingers configured to be movable in and out of the direction intersecting the radiant beam in order to adjust (e.g., correct) the intensity of each portion of the radiant beam. The uniformity correction system may include actuators coupled to one or more fingers and configured to move the corresponding fingers.

[0013] Changes in the thermal state (e.g., temperature) of one or more components of a lithography apparatus can cause undesirable changes in the intensity profile of the radiated beam (e.g., slit uniformity). Undesirable changes in the intensity profile of the radiated beam can cause lithography errors, such as adversely affecting the uniformity of the critical dimensions of the lithography apparatus. Lithography errors can result in the formation of inaccurate patterns on the substrate, potentially leading to defects in the devices manufactured by the lithography apparatus. The control system favorably uses thermal state criteria to monitor (e.g., directly and / or indirectly measure and / or estimate) and / or predict the temperature and / or temperature changes of parts of the lithography apparatus. The control system uses thermal criteria to control the uniformity correction system, thereby at least partially accounting for undesirable changes in the intensity profile of the radiated beam caused by thermal effects. The control system favorably reduces lithography errors without unduly reducing the throughput of the lithography apparatus.

[0014] A thermal state criterion may indicate the thermal state of a part of the lithography apparatus that directly or indirectly receives heat generated by a radiation beam. The thermal state criterion may include the temperature of a part of the lithography apparatus. The thermal state criterion may include parameters correlated with the temperature of a part of the lithography apparatus. The thermal state criterion may include predetermined and / or monitored radiation dose information. The thermal state criterion may include predetermined and / or monitored radiation pulse information. The temperature may be absolute temperature. The temperature may be relative temperature. For example, the temperature may be related to one or more other parts of the lithography apparatus at simultaneous or different points in time. As another example, the temperature may be related to a predetermined reference temperature.

[0015] The control system may be a feedforward control system. A feedback control system can be thought of as a control system whose output depends on the feedback signal that generates it. A feedforward control system can be thought of as a system that passes a signal to an external load and eliminates disturbances before they affect the controlled variable. In other words, in feedback control, the variable is adjusted based on errors. In feedforward control, the variable is adjusted based on knowledge of parameters that may cause errors (such as thermal conditions).

[0016] The control system may be a dynamic control system. That is, the control system may actively respond to parameter changes rather than simply applying a static control regime that does not adapt to parameter changes. In other words, a static control system cannot respond to certain thermal conditions that affect imaging performance during lithography exposure. A fixed number of static uniformity correction events can be added during the exposure of a substrate lot, but this negatively impacts the throughput of the lithography apparatus because additional compensation is performed for all substrate lots according to the static control regime. A dynamic control system favorably triggers dynamic uniformity correction events only when necessary, thereby reducing lithography errors while minimizing the negative impact on throughput.

[0017] The control system may be configured to control the uniformity correction system based at least partially on a comparison between the thermal state criterion and the reference thermal state criterion.

[0018] The reference thermal state criterion may include a reference temperature of a part of the lithography apparatus. The reference thermal state criterion may include a reference parameter that correlates with a part of the temperature of the lithography apparatus. The reference thermal state criterion can be determined by performing a calibration to determine the relationship between the intensity profile of the radiated beam and the thermal state criterion.

[0019] The reference thermal state criterion may include predetermined limits. The control system may be configured to cause the uniformity correction system to adjust the intensity profile of the radiated beam when the thermal state criterion reaches predetermined limits.

[0020] The thermal state criterion may include a predictive component.

[0021] The prediction component can be calculated based at least partially on predetermined lithography exposure information.

[0022] Lithography exposure information may include radiation dose information. Lithography exposure information may include radiation pulse information.

[0023] Thermal condition criteria may include monitored components.

[0024] A lithography apparatus may include a sensing system configured to measure the temperature of a portion of the lithography apparatus. The monitored component may include measurements performed by the sensing system.

[0025] A lithography apparatus may include a cooling system configured to provide a flow of coolant for cooling a portion of the lithography apparatus. A sensing system may be configured to measure the temperature of the coolant.

[0026] The cooling system can be configured to cool the mirror array of the lithographic apparatus.

[0027] The lithographic apparatus can comprise an optical element configured to interact with a radiation beam. The lithographic apparatus can comprise a support structure configured to support the optical element. The detection system can be configured to measure the temperature of the optical element and / or the support structure.

[0028] The lithographic apparatus can comprise a support device configured to hold a patterning device. The patterning device can be configured to impart a pattern in a cross-section of the radiation beam to form a patterned radiation beam. The lithographic apparatus can comprise a reticle masking blade system configured to selectively block the patterned radiation beam. The detection system can be configured to measure the temperature of the support device and / or the reticle masking blade system.

[0029] The lithographic apparatus can comprise a measurement system configured to measure a thermal deformation of a part of the lithographic apparatus. The monitored component can include the measurement values performed by the measurement system.

[0030] The thermal deformation can include a thermal expansion of a part of the lithographic apparatus. The thermal deformation can include a thermal contraction of a part of the lithographic apparatus.

[0031] The measurement system can comprise a reflective surface and an arm extending from a surface opposite to the reflective surface. The measurement system can comprise a support frame provided with a detection device configured to measure a gap between the detection device and the arm. The monitored component can include the gap measured by the measurement system.

[0032] The reflective surface can form part of a mirror array. The mirror array can form part of an illumination system. The mirror array can be a field facet mirror array.

[0033] The detection device may be configured to measure the gap between the detection device and the end of the arm. Magnetic material and / or inductive material may be provided at the end of the arm. The detection device may include an eddy current sensor.

[0034] The measurement system may include a reflector configured to reflect at least a portion of the radiation beam. The measurement system may include a sensor configured to measure the position of the reflected portion of the radiation beam. The monitored component may include the position of the reflected portion of the radiation beam as measured by the measurement system.

[0035] The measurement system may include a processor configured to determine the alignment between the illumination system and the radiation beam source, at least partially based on the detection position of a portion of the reflected radiation beam.

[0036] The monitored components may include lithography exposure information.

[0037] Lithography exposure information may include radiation dose information. Lithography exposure information may include radiation pulse information.

[0038] The control system may be configured to control the uniformity correction system using a thermal state criterion during lithography exposure of the substrate.

[0039] A second aspect of this disclosure provides a method for controlling a radiation beam for lithography. This method includes adjusting the radiation beam and adjusting the intensity profile of the radiation beam at least in part to a thermal state criterion indicating the heat generated by the radiation beam.

[0040] This method may include comparing a thermal state criterion with a reference thermal state criterion. This method may also include adjusting the intensity profile of the radiated beam based at least partially on the comparison.

[0041] The reference thermal state criterion may include predetermined limits. This method may include adjusting the intensity profile of the radiated beam when the thermal state criterion reaches predetermined limits.

[0042] The thermal state criterion may include a predictive component.

[0043] The prediction component can be calculated based at least partially on predetermined lithography exposure information.

[0044] Thermal condition criteria may include the components being monitored.

[0045] The monitored components may include temperature measurements and / or thermal deformation measurements.

[0046] The monitored components may include lithography exposure information.

[0047] This method may include determining a relationship between the intensity profile of a radiated beam and a thermal state criterion. This method may include determining a reference thermal state criterion using the said relationship. This method may include adjusting the intensity profile of a radiated beam based at least partially on the reference thermal state criterion.

[0048] Methods for projecting a patterned radiation beam onto a substrate may include methods of a second aspect of the present disclosure.

[0049] A computer program may include computer-readable instructions configured to cause a computer to perform a method according to a second aspect of this disclosure. A computer-readable medium may include a computer program.

[0050] A computer device may include a memory for storing processor-readable instructions and a processor configured to read and execute instructions stored in the memory. Processor-readable instructions may include instructions configured to control the computer to perform a method according to a second aspect of the present disclosure. [Brief explanation of the drawing]

[0051] The following description of the illustrations of exemplary embodiments may further illustrate and describe improved aspects of the concept. Components and parts of a lithography apparatus having the same structure and effect are indicated by equivalent reference numerals. The following descriptions of components and parts of a lithography apparatus are not repeated insofar as they correspond to each other in terms of function in different figures.

[0052] Embodiments of the present invention will be described for illustrative purposes only with reference to the following schematic accompanying drawings. [Figure 1] This is a schematic diagram showing a lithography system comprising a radiation source and a lithography apparatus. [Figure 2A] This is a schematic diagram illustrating the uniformity correction system. [Figure 2B] Figure 2A schematically shows the effect of using the uniformity correction system. [Figure 2C] Figure 2A schematically shows the effect of using the uniformity correction system. [Figure 3] This is a schematic diagram showing a mirror assembly of a faceted field device. [Figure 4A] This figure shows a graph of the relationship between the thermal state criterion and the heterogeneity of the intensity profile of the radiation beam used by the lithography apparatus according to this disclosure. [Figure 4B] This figure shows graphs of radiation beam non-uniformity and thermal state-based characteristics during lithography exposure of three substrate lots according to this disclosure. [Figure 5] This figure shows a flowchart illustrating the method for controlling a radiation beam for lithography according to this disclosure. [Modes for carrying out the invention]

[0053] Figure 1 shows a lithography system comprising a radiation source SO and a lithography apparatus LA equipped with a uniformity correction system 16 and a control system 170 according to the present disclosure. The radiation source SO is configured to generate an (EUV) radiation beam B and to supply the EUV radiation beam B to the lithography apparatus LA. The lithography apparatus LA comprises an illumination system IL, a support structure MT configured to support a patterning device MA (e.g., a reticle or mask), a projection system PS, and a substrate table WT configured to support a substrate.

[0054] The illumination system IL is configured to adjust the EUV radiation beam B before it is incident on the patterning device MA. Furthermore, the illumination system IL may include a faceted field mirror device 10 and a faceted pupil mirror device 11. The faceted field mirror device 10 is a mirror array composed of individually controllable mirrors. The mirrors in the array, together with associated actuators and sensing devices (described in more detail below), may be referred to as a mirror assembly. A controller (not shown) controls the orientation of the mirrors (described further below). Together, the faceted field mirror device 10 and the faceted pupil mirror device 11 provide an EUV radiation beam B having a desired cross-sectional shape and a desired intensity distribution. In addition to, or instead of, the illumination system IL may include other mirrors or devices. The illumination system IL comprises a reticle masking blade system 18. The reticle masking blade system 18 comprises a pair of blades movable in the scanning direction of the lithography apparatus LA. The reticle masking blade system 18 can be used to prevent radiation from being incident on target regions adjacent to a given target region in the y-direction and / or x-direction during exposure of that target region.

[0055] After this adjustment, the EUV radiation beam B interacts with the patterning device MA. This interaction results in the generation of a patterned EUV radiation beam B'. The projection system PS is configured to project the patterned EUV radiation beam B' onto a substrate W. For this purpose, the projection system PS may comprise several mirrors 13, 14 configured to project the patterned EUV radiation beam B' onto the substrate W, which is held by a substrate table WT. The projection system PS can apply a reduction factor to the patterned EUV radiation beam B', thereby forming an image with features smaller than the corresponding features on the patterning device MA. For example, a reduction factor of 4 or 8 may be applied. Although the projection system PS is shown in Figure 1 with only two mirrors 13, 14, the projection system PS may include a different number of mirrors (e.g., six or eight mirrors).

[0056] The substrate W may contain a previously formed pattern. In this case, the lithography apparatus LA aligns the image formed by the patterned EUV radiation beam B' with the previously formed pattern on the substrate W.

[0057] A small amount of gas (e.g., hydrogen) at a relative vacuum, i.e., a pressure considerably lower than atmospheric pressure, may be provided within the radiation source SO, the illumination system IL, and / or the projection system PS.

[0058] The radiation source SO shown in Figure 1 is of a type also known as a laser-generated plasma (LPP) source. For example, a laser system 1 including a CO2 laser is configured to store energy via a laser beam 2 in a fuel such as tin (Sn) supplied from a fuel ejector 3. Although tin is mentioned below, any suitable fuel may be used. The fuel may be, for example, liquid, or it may be a metal or alloy. The fuel ejector 3 may include a nozzle that guides the tin, for example, in the form of droplets, along a trajectory toward the plasma-forming region 4. The laser beam 2 is incident on the tin in the plasma-forming region 4. The storage of laser energy in the tin forms a plasma 7 in the plasma-forming region 4. Radiation, including EUV radiation, is emitted from the plasma 7 during the de-excitation and recombination of electrons and plasma ions.

[0059] EUV radiation from the plasma is collected and focused by a collector 5. The collector 5 comprises, for example, a nearly perpendicular incidence radiation collector 5 (sometimes more commonly called a perpendicular incidence radiation collector). The collector 5 may have a multilayer mirror structure configured to reflect EUV radiation (e.g., EUV radiation having a desired wavelength such as 13.5 nm). The collector 5 may have an ellipsoidal structure with two foci. As described below, the first focal point may be located in the plasma-forming region 4, and the second focal point may be located in an intermediate focal point 6.

[0060] The laser system 1 may be spatially separated from the radiation source SO. In this case, the laser beam 2 may pass from the laser system 1 towards the radiation source SO with the help of a beam transport system (not shown) equipped with, for example, appropriate directional mirrors and / or a beam expander and / or other optical systems. The laser system 1, the radiation source SO, and the beam transport system may all be considered a radiation system.

[0061] The radiation reflected by collector 5 forms EUV radiation beam B. EUV radiation beam B is focused at intermediate focus 6, forming an image of the plasma present in plasma-forming region 4 at intermediate focus 6. The image at intermediate focus 6 functions as a virtual radiation source for illumination system IL. Radiation source SO is configured such that intermediate focus 6 is located at or near the aperture 8 of the surrounding structure 9 of radiation source SO.

[0062] Figure 1 shows the SO radiation source as a laser-generated plasma (LPP) source, but EUV radiation can be generated using any suitable radiation source, such as a discharge-generated plasma (DPP) source or a free-electron laser (FEL).

[0063] The illumination system IL includes a uniformity correction system 16. In one example, the uniformity correction system 16 is positioned in the path of the radiation beam B, before the reticle masking blade system 18, so that the radiation beam can pass through the uniformity correction system 16 before it is incident on the reticle masking blade system 18. The uniformity correction system 16 may be configured to spatially control the intensity of the radiation beam B. That is, the uniformity correction system 16 may be configured to spatially control the intensity profile of the radiation projected onto the substrate W. The uniformity correction system 16 may be located within or near the field of view of the illumination system IL. In one embodiment, the uniformity correction system 16 includes at least one array of overlapping fingers (e.g., banks 22, 23 of fingers shown in Figure 2A) and / or at least one array of non-overlapping fingers. The fingers can move in and out in a direction intersecting the radiation beam incident on the fingers, and can selectively correct the intensity of a portion of the radiation beam. In the example in Figure 2A, seven fingers are shown in each bank, but it should be understood that any number of fingers can be used. The terms bank of fingers, finger bank, finger bank, or bank may be used interchangeably throughout this application.

[0064] The lithography apparatus LA includes a control system 170 configured to control a uniformity correction system 16. The control system 170 may be configured to determine the adjustment of the fingers (shown in Figure 2A) of the uniformity correction system 16 so that a desired uniformity specification is met. The control system 170 may be configured to determine one or more correction parameters based on the determined adjustments and to communicate these parameters to the uniformity correction system 16. The correction parameters may control adjustable variables within the uniformity correction system 16. The control system 170 may receive illumination field data collected from one or more uniformity measuring devices (not shown). By manipulating the adjustable variables of the uniformity correction system 16 according to the correction parameters, the characteristics of the radiated beam B can be changed. More specifically, the correction parameters may provide details on how to adjust the variables of the uniformity correction system 16 to achieve a desired uniformity profile (e.g., the flattest uniformity or shape beneficial to the lithography process). For example, the correction parameters can represent which fingers within a bank of one or more fingers (e.g., finger banks 22 and 23 in Figure 2A) need to move, and how far they need to move to enter and exit the intersection with the incident radiation beam in order to selectively correct the intensity of the portion of the radiation beam incident on the uniformity correction system 16.

[0065] The control system 170 may include one or more processors and memory. One or more processors may run software that causes the uniformity correction system 16 to adjust variables to achieve a desired uniformity standard of the radiation beam. The computer program may be stored in memory. When such a computer program is executed, it may enable the processors in the control system 170 to perform features of one embodiment of the present disclosure as described herein. If the method for controlling the uniformity correction system 16 is implemented using software, the software may be stored in a computer program product and loaded into the control system 170 using a removable storage device, a hard drive, or a communication interface. Alternatively, the computer program product may be downloaded into the control system 170 via a communication path. The control system 170 may be connected to one or more remote processors. The control system 170 may remotely receive and / or transmit instructions and / or operating parameters.

[0066] Figure 2A schematically shows the uniformity correction system 16, and Figures 2B and 2C schematically show the effect of using the uniformity correction system 16 of Figure 2A. The uniformity correction system 16 may comprise two banks 22 and 23 of fingers that are movable in the Y direction to intersect the radiation beam. In this way, the fingers 22, 23 may be used to selectively block incident radiation. This may be done, for example, to reduce the intensity of radiation at a location in the radiation beam field where the radiation intensity is too high. The fingers 22, 23 may be coupled to an actuator (not shown). The actuator may be configured to move the fingers 22, 23 in the Y direction. The actuator may comprise one or more of the following: a motor, a piezoelectric device, a hydraulic device, etc.

[0067] Figures 2B and 2C show cross-sectional views of the uniformity correction system 16. As shown in Figures 2B and 2C, the finger banks 22 and 23 of the uniformity correction system 16 are positioned on the field plane FP1 of the lithography apparatus. On this plane FP1, the radiant beam 36 includes an array of virtual radiation sources 30. In the reticle masking blade 18, the radiant beam 36, represented by multiple sub-beams, diverges. In the example of Figure 2B, the fingers in finger banks 22 and 23 are positioned so as not to intersect the radiant beam 36. In Figure 2C, the fingers in finger banks 22 and 23 are moved in the Y direction so as to intersect the radiant beam 36. The intensity profile of the radiant beam 36 is adjusted by selectively moving one or more fingers in finger banks 22 and 23 to selectively correct the intensity of portions of the radiant beam 36 and form a corrected radiant beam. The fingers can be individually controlled to change the intensity of the illumination slits formed by the radiant beam 36 in order to achieve the desired uniformity.

[0068] Referring again to Figure 1, the amount of power output from radiation source 1 can change over time. The thermal state of one or more parts of the lithography apparatus LA can also change over time. For example, the temperature of one or more parts of the lithography apparatus LA may rise during exposure of substrate W. Between exposures, the temperature of one or more parts of the lithography apparatus LA may decrease. Increasing the power of radiation source 1 increases the operating speed of the lithography apparatus LA, thereby increasing the number of substrates W exposed per hour by the lithography apparatus LA (sometimes called throughput). However, increasing the power output of radiation source 1 can raise the maximum temperature reached by one or more parts of the lithography apparatus LA, potentially increasing the gradient of temperature change.

[0069] Temperature changes in one or more parts of the lithography apparatus LA can cause undesirable changes in the intensity profile of the radiation beam B (e.g., slit uniformity). Undesirable changes in the intensity profile of the radiation beam B can cause lithography errors, such as adversely affecting the uniformity of the critical dimensions of the lithography apparatus LA. For example, the facet field mirror device 10 may receive heat from the radiation beam B during exposure of the substrate W and undergo thermal deformation (e.g., thermal expansion). Thermal deformation of the facet field mirror device 10 can result in undesirable changes in the intensity profile of the radiation beam B reflected from the facet field mirror device 10.

[0070] The control system 170 is configured to control the uniformity correction system 16 based at least partially on a thermal state criterion that indicates the thermal state of a portion of the lithography apparatus LA. A portion of the lithography apparatus LA can receive energy directly from the radiant beam B (e.g., through partial absorption of the radiant beam B). A portion of the lithography apparatus LA can receive energy indirectly from the radiant beam B (e.g., through heat transfer from one part of the lithography apparatus to another). For example, additional uniformity correction (e.g., in addition to the default uniformity correction performed at the start of each substrate lot) may be triggered when the thermal state criterion (corresponding to the thermal state of one or more parts of the lithography apparatus LA) reaches or exceeds a reference thermal state criterion. This allows the control system 170 to maintain a desired intensity profile of the radiant beam B despite thermal drift in one or more parts of the lithography apparatus LA. The control system 170 can cause the uniformity correction system 16 to perform additional uniformity correction only when necessary to maintain the desired intensity profile of the radiant beam B. In other words, the additional uniformity correction required to maintain the desired slit uniformity can be minimized, thereby reducing lithography errors while minimizing the impact on the throughput of the lithography apparatus LA.

[0071] Many different parameters can contribute to the thermal state criterion. For example, the thermal state criterion may include the temperature of a part of the lithography apparatus LA. The lithography apparatus LA may include a sensing system configured to measure the temperature of one or more parts of the lithography apparatus LA that receive heat from the radiation beam B. In the example in Figure 1, the sensing system comprises four temperature sensors 201-204. The first temperature sensor 201 is configured to measure the temperature of the facet field device 10 and / or the support structure configured to support the facet field device 10. The second temperature sensor 202 is configured to measure the temperature of the reticle masking blade system 18. The third temperature sensor 203 is configured to measure the temperature of the support structure MT that holds the reticle MA. The fourth temperature sensor 204 is configured to measure the temperature of the coolant 215 that forms part of a cooling system 210 configured to control the temperature of the facet pupil mirror device 11. Each of these parts of the lithography apparatus LA receives heat generated by the radiation beam B, directly or indirectly. The temperatures measured by the temperature sensors 201-204 of the sensing system can be used as a thermal state reference. For example, if one or more of the temperature sensors 201-204 detect a temperature and / or temperature change exceeding a predetermined limit, the control system 170 can cause the uniformity correction system 16 to adjust the intensity profile of the radiant beam B to compensate for the associated thermal drift effect. The sensing system may comprise more or fewer temperature sensors 201-204. The sensing system may also include other temperature sensors associated with other parts of the lithography apparatus LA, such as coolant forming part of another cooling system (not shown) configured to cool the facet field device 10.

[0072] As another example, the thermal state criterion may include parameters that correlate with the temperature of a portion of the lithography apparatus LA that receives heat generated by the radiation beam B. The lithography apparatus LA may include a measurement system configured to measure one or more parameters that correlate with the temperature of a portion of the lithography apparatus LA. For example, the measurement system may be configured to measure the thermal deformation of a portion of the lithography apparatus LA that receives heat generated by the radiation beam B. The thermal deformation of a portion of the lithography apparatus LA (e.g., thermal expansion and / or thermal contraction) may correlate with undesirable changes in the intensity profile of the radiation beam B caused by the thermal effects. Monitoring and / or predicting the thermal deformation of one or more portions of the lithography apparatus LA may contribute to the thermal state criterion used to control the uniformity correction system 16.

[0073] In the example shown in Figure 1, the measurement system comprises an alignment system comprising a faceted field device 10 and a sensor 220 configured to measure the position of the reflective portion of the radiant beam B in the faceted pupil mirror device 11. The alignment system can typically be used to determine the alignment between the radiation source SO and the illumination system IL. However, the information generated by the alignment system can be usefully contributed to the thermal state criteria used to control the uniformity correction system 16. For example, when the faceted field device 10 undergoes thermal deformation due to the heat generated by the radiant beam B, the direction in which the faceted field device 10 reflects a portion of the radiant beam B may change. The sensor 220 can detect the corresponding change in the position of the portion of the radiant beam B in the faceted pupil mirror device 11. The greater the temperature change of the faceted field device 10, the greater the change in the direction of the portion of the radiant beam B, and the greater the change in the detected position of the radiant beam B by the sensor 220. Therefore, the change in the position of the radiant beam B measured by the sensor 220 correlates with the temperature change of the faceted field device 10, which in turn correlates with an undesirable change in the intensity profile of the radiant beam B. Therefore, the measurements performed by the sensor 220 can be used by the control system 170 to cause the uniformity correction system 16 to adjust the intensity profile of the radiant beam B to account for the thermal deformation of the facet field device 10. It will be understood that the measurement system is not limited to the facet field device 10 and the facet pupil mirror device 11. That is, other reflective surfaces may be used and / or introduced into the lithography apparatus LA, and the sensor 220 may be located elsewhere in the lithography apparatus LA.

[0074] The measurement system may be configured to measure different or additional parameters that indicate the thermal deformation of a portion of the lithography apparatus LA. Figure 3 schematically shows a mirror assembly 19 (an example of a mirror array) of the facet field device 10. The outer surface 22 of the mirror 20 is reflective to EUV radiation and has a multilayer structure formed, for example, from layers of alternating reflectivity. An arm 24 extends from the surface 26 of the mirror opposite to the reflective surface 22. Surface 26 may be called the back surface of the mirror. The arm 24 is connected to the center of the back surface 26 of the mirror (although it may be connected to other points on the back surface of the mirror). The connection between the arm 24 and the mirror 20 is fixed, and movement of the arm 24 causes movement of the mirror 20. A leaf spring 28 also extends from the back surface of the mirror 20. A connector 34 receives the leaf spring 28 and is then connected to a support structure 30. Thus, the leaf spring 28 is connected to the support structure 30 via the connector 34, thereby supporting the mirror 20. The arm 24 is not connected to the support structure 30, but instead passes through the opening 32 of the support structure. Any number of leaf springs 28 can be provided. Other forms of connections may be provided. Different forms of elastic connections may be provided (e.g., some other form of spring). Similarly, the connector may have other shapes and / or configurations. The connector 34 may be omitted.

[0075] The leaf spring 28 elastically biases the mirror 20 and the arm 24 to an equilibrium orientation. The equilibrium orientation corresponds to the reflective surface 22 of the mirror 20 being substantially parallel to the surface of the support structure and the arm 24 passing through the center of the opening 32 of the support structure. The leaf spring 28 can bias the mirror 20 to other equilibrium orientations. A magnet 40 is located at the end of the arm 24. A layer of inductive material 42 may be provided on the magnet 40. The magnet 40 may be configured to apply force to the arm 24 to move the arm and mirror 20 to different orientations. The inductive material 42 may be configured to measure the orientation of the arm 24 (and mirror 20). The magnet 40 and the inductive material 42 may include any suitable material. The magnet 40 and the inductive material 42 may include a single material (e.g., an iron material that is both magnetic and inductive).

[0076] The electromagnets 44a and 44c are supported by a second support structure 46. The second support structure 46 may be connected to a support structure 30 that supports the mirror 20, so as a whole, a single support structure is provided. The electromagnets 44a and 44c are separated in the y direction. Two additional magnets (not shown) may be provided and separated in the x direction. Cartesian coordinates are used in this description for ease of understanding, and the usual lithographic convention that the direction of the radiation beam is in the z direction is used. The electromagnets 44a and 44c and the magnet 40 on the arm 24 are an example of a mirror actuator. Other types of mirror actuators, such as other types of electromagnetic actuators, or permanent magnets driven by mechanical actuators may also be used. Eddy current sensors 48a and 48c are provided at the ends of each electromagnet 44a and 44c. The eddy current sensors 48a and 48c are an example of a detection device. Other types of detection devices may be used. For example, the detection device may comprise an optical sensor configured to measure the position and / or phase of the radiation beam reflected from the surface of the magnet 40. A controller (not shown) supplies current to electromagnets 44a and 44c to generate a magnetic field that applies a desired force to the magnet 40, thereby moving the magnet to the desired position. This causes the arm 24 to rotate and the mirror 20 to move to the desired orientation. The controller may be used to control the orientation of the mirror 20 in the array. The controller receives measurements from eddy current sensors 48a and 48c associated with the mirror and may use these measurements as feedback when controlling the current supplied to the electromagnets 44a and 44c.

[0077] The mirror assembly 19 shown in Figure 3 is part of an array of mirrors. The array of mirrors may be a faceted field mirror device 10 (as shown in Figure 1). During use, as further described above, it may be desirable to form a specific illumination mode on the faceted pupil mirror device 11. This can be achieved by selecting the orientation of the mirrors 20 of the faceted field mirror device 10 so that the radiant beam is directed to a specific desired position on the faceted pupil mirror device 11. For example, the mirrors 20 may be directed to guide radiation to two zones on the faceted pupil mirror device 11 to form a bipolar mode, or they may be directed to guide radiation to four zones on the faceted pupil mirror device to form a quadrupole mode.

[0078] Mirror 20 reflects EUV radiation, but is not a perfect reflector and may instead reflect about 60% of the incident EUV radiation. Thus, a considerable amount of EUV radiation is absorbed by mirror 20, causing the mirror to heat up. Arm 24 is made of metal (e.g., steel, copper, or alloy) and is thermally connected to mirror 20. The thermal connection between arm 24 and mirror 20 may be such that when the mirror heats up to a given temperature, the arm also heats up to substantially the same temperature. Arm 24 may have a length of several centimeters (e.g., between about 5 centimeters and about 10 centimeters, e.g., about 7 centimeters). Arm 24 may have a considerable coefficient of thermal expansion. Thus, as arm 24 heats up, it expands due to thermal expansion. The thermal expansion of arm 24 causes the magnet 40 and inductive material 42 to move toward the eddy current sensors 48a, 48c and electromagnets 44a, 44c. When the radiation beam no longer enters the mirror (for example, between exposures of a substrate and / or substrate lot), the temperature of the arm 24 decreases and it may undergo thermal contraction. Since the arm 24 is not fixed to the support structure 30, it expands and contracts freely due to heat. The thermal expansion and / or contraction of the arm 24 changes the gap 60 between the magnet 40 and the eddy current sensors 48, 48c.

[0079] Thermal deformation of the facet field mirror device 10 can contribute to undesirable changes in the intensity profile of the radiation beam. The thermal deformation of the arm 24 (e.g., expansion and / or contraction) is determined by the temperature of the arm 24, which may be determined by the temperature of the mirror 20. The temperature of the mirror 20 may be determined by the amount of energy from the radiation beam absorbed by the mirror. Measuring the thermal deformation of the arm 24 yields an output indicating an undesirable change in the intensity profile of the radiation beam. The thermal expansion and / or contraction of the arm 24 can be measured by measuring the change in distance between the inductive material 42 and the eddy current sensors 48a, 48c. This is referred to as measuring the change in the gap 60 between the inductive material 42 and the eddy current sensors 48a, 48c. The gap 60 is shown as a point between the eddy current sensors 48a, 48c, and a dotted line is included to guide the eye. The gap 60 between the inductive material 42 and the eddy current sensors 48a, 48c can be measured using the eddy current sensors. Output signals from eddy current sensors 48a and 48c may be used to measure the gap 60. The control system 170 may use the measured gap 60 as a thermal state reference and control the uniformity correction system 16 at least partially dependent on the measured gap 60. Output signals may be obtained from multiple or all of the sensor arrays forming the facet field mirror device 10 and used as a thermal state reference.

[0080] Figure 4A shows a graph of the relationship between the thermal state criterion and the non-uniformity of the intensity profile of the radiation beam used by the lithography apparatus. The thermal state criterion may include monitored components such as temperature (e.g., measured by one or more of the temperature sensors 201-204 shown in Figure 1) and / or temperature-correlated parameters (e.g., thermal deformation measurements performed by sensor 220 shown in Figure 1 and / or sensor devices 48a, 48c shown in Figure 3). The thermal state criterion may additionally or alternatively include predictive components. The predictive components can be determined at least in part on predetermined lithography exposure information indicating how much heat is generated by the radiation beam during use of the lithography apparatus. The lithography exposure information may include, for example, radiation dose information (e.g., the amount of energy transferred to substrate W and / or substrate lot by radiation beam B), radiation pulse information (e.g., the power and / or duration of the pulses forming radiation beam B), lithography exposure time, and the number of substrates exposed. The thermal properties (e.g., coefficient of thermal expansion) of one or more parts of a lithography apparatus are known and can be used to model the thermal behavior of the lithography apparatus.

[0081] Calibration can be performed to determine the relationship 300 between the uniformity of the radiation beam and a thermal state criterion. For example, the uniformity of the radiation beam may be measured as the temperature of one or more components of the lithography apparatus changes, and the thermal state criterion may be monitored throughout the lithography exposure. A limit (e.g., the maximum allowable non-uniformity of the radiation beam 310) can be determined in advance (e.g., based on the maximum allowable change in the uniformity of the critical dimension for a given pattern printed on a substrate). A reference thermal state criterion 320 corresponding to the maximum allowable non-uniformity of the radiation beam 310 may be provided and / or stored in the memory of the control system 170 for reference during use of the lithography apparatus LA. The control system 170 may be configured to control the uniformity correction system 16 at least in part on a comparison between the thermal state criterion and the reference thermal state criterion 320.

[0082] For example, the thermal state criterion may include the predicted temperature of a portion of the lithography apparatus. The predicted temperature of a portion of the lithography apparatus can be modeled for a given lithography exposure. For example, the predicted temperature of a portion of the lithography apparatus can be modeled using the following exponential relationship:

number

[0083] Figure 4B shows graphs of radiation beam heterogeneity 301 and thermal state criterion 302 during lithography exposure of three substrate lots 401-403. At the start of exposure of the first substrate lot 401, the lithography apparatus LA starts in a "cold" thermal state and rapidly heats up due to the presence of the radiation beam, causing the radiation beam heterogeneity 301 to increase sharply. The thermal state criterion 302 also increases sharply because the thermal state criterion indicates the thermal state of the lithography apparatus and is therefore correlated with the radiation beam heterogeneity 301. When the thermal state criterion 302 reaches the reference thermal state criterion 320, a dynamic uniformity correction event 410 is triggered, and the control system causes the uniformity correction system to adjust the intensity profile of the radiation beam, thereby reducing the radiation beam heterogeneity. As a result, the radiation beam heterogeneity 301 remains below the maximum allowable heterogeneity 310. The radiation beam heterogeneity 301 continues to rise, but at a slower rate as the lithography apparatus continues to heat up. The thermal state criterion 302 reaches the reference thermal state criterion 320 again during the first substrate lot 401, triggering another dynamic uniformity correction event 410 in which the control system causes the uniformity correction system to adjust the intensity profile of the radiation beam to reduce the non-uniformity of the radiation beam. As the lithography apparatus approaches a new thermal equilibrium in the presence of heat generated by the radiation beam, the radiation beam non-uniformity 301 continues to increase, but at a slower rate. The first substrate lot 401 is completed before the thermal state criterion 302 reaches the reference thermal state criterion 320, triggering the first static uniformity correction event 421. Static uniformity correction events 421 and 422 may be triggered at the end of each substrate lot 401-403 as a standard. During the exposure of the second substrate lot 402, the thermal state criterion 302 reaches the reference thermal state criterion 320 again at a slower rate due to the increased thermal stability of the lithography apparatus. A dynamic uniformity correction event 410 is triggered, causing the control system to instruct the uniformity correction system to adjust the intensity profile of the radiated beam and reduce the non-uniformity of the radiated beam. Before the thermal state criterion 302 reaches the reference thermal state criterion 320 again, the second substrate lot 402 is completed, and a second static uniformity correction event 422 is triggered.Exposure of the third substrate lot 403 begins with a radiation beam heterogeneity 301 well below the maximum allowable heterogeneity 310, and a thermal state criterion 302 well below the reference thermal state criterion 320. As the lithography apparatus reaches a new thermal equilibrium, the rate of increase over time in radiation beam heterogeneity and thermal state criterion decreases.

[0084] The process in Figure 4B can be used for any desired thermal state criterion. The thermal state criterion can be continuously monitored, or it can be determined at predetermined intervals. For example, the thermal state criterion may be determined before lithography exposure of each substrate. The change in the thermal state criterion between consecutive substrates can be determined. When the change in the thermal state criterion reaches a predetermined limit, a dynamic uniformity correction event is triggered as early as possible (e.g., before lithography exposure of the next substrate) to maintain the uniformity of the radiation beam at an acceptable level. After the dynamic uniformity correction event occurs, the thermal state criterion can be measured again and used as a reference point for subsequent measurements of the thermal state criterion.

[0085] Figure 5 shows a method for controlling a radiation beam for lithography. The first step 501 of the method includes adjusting the radiation beam. The first step 501 may also include providing a radiation beam having a desired cross-sectional shape and a desired intensity distribution. The second step 502 of the method includes adjusting the intensity profile of the radiation beam, at least in part on a thermal state criterion indicating the heat generated by the radiation beam. The second step 502 may also include spatially controlling the intensity profile of the radiation beam. The second step 502 may also include selectively blocking a portion of the radiation beam to selectively correct the intensity of a portion of the radiation beam. The heat generated by the radiation beam may include energy absorbed from the radiation beam by one or more optical components used to adjust the radiation beam.

[0086] In summary, the apparatus and method of the present disclosure enable the uniformity correction system to dynamically respond to changing thermal conditions during the operation of the lithography apparatus, thereby reducing lithography errors while minimizing the impact on throughput.

[0087] The present invention can also be summarized by the following clauses. 1. A lithography device, A lighting system configured to adjust the radiation beam, A uniformity correction system configured to adjust the intensity profile of the radiation beam, A control system configured to control the uniformity correction system based at least partially on a thermal state criterion that indicates a part of the thermal state of the lithography apparatus, A lithography apparatus equipped with [a specific feature / feature]. 2. The lithography apparatus according to item 1, wherein the control system is configured to control the uniformity correction system at least in part based on a comparison between the thermal state criterion and a reference thermal state criterion. 3. The lithography apparatus according to item 2, wherein the reference thermal state criterion includes a predetermined limit, and the control system is configured to cause the uniformity correction system to adjust the intensity profile of the radiated beam when the thermal state criterion reaches the predetermined limit. 4. The lithography apparatus described in any of the above sections, including a predictive component, which is the thermal state criterion. 5. The lithography apparatus according to item 4, wherein the prediction component is calculated at least in part based on predetermined lithography exposure information. 6. The thermal condition criterion is a lithography apparatus as described in any of the above sections, including the component to be monitored. 7. The lithography apparatus according to item 6, comprising a sensing system configured to measure the temperature of a portion of the lithography apparatus, wherein the monitored component includes measurements performed by the sensing system. 8. The lithography apparatus according to item 7, comprising a cooling system configured to provide a flow of coolant for cooling a portion of the lithography apparatus, wherein the sensing system is configured to measure the temperature of the coolant. 9. An optical element configured to interact with the radiation beam, The system comprises a support structure configured to support the optical element, The lithography apparatus according to claim 7 or 8, wherein the detection system is configured to measure the temperature of the optical element and / or the support structure. 10. A support device configured to hold a patterning device, wherein the patterning device is configured to give a pattern to the cross-section of the radiation beam to form a patterned radiation beam. A reticle masking blade system configured to selectively block the patterned radiation beam, wherein the detection system is configured to measure the temperature of the support device and / or the reticle masking blade system, A lithography apparatus according to any one of claims 7 to 9, comprising: 11. A lithography apparatus according to any one of items 6 to 10, comprising a measurement system configured to measure the thermal deformation of a portion of the lithography apparatus, wherein the monitored component includes measurements performed by the measurement system. 12. The measurement system is A reflective surface configured to reflect at least a portion of the radiation beam, and an arm extending from the surface opposite to the reflective surface, The system comprises a support frame on which a detection device is provided, configured to measure the gap between the detection device and the arm, The lithography apparatus according to item 11, wherein the monitored component includes a gap measured by the measurement system. 13. The measurement system is A reflector configured to reflect at least a portion of the aforementioned radiation beam, The system includes a sensor configured to measure the position of the reflective portion of the radiation beam, The lithography apparatus according to claim 11 or 12, wherein the monitored component includes the position of the reflective portion of the radiation beam measured by the measurement system. 14. The lithography apparatus according to any one of items 6 to 13, wherein the monitored component includes lithography exposure information. 15. The lithography apparatus according to any of the above paragraphs, wherein the control system is configured to control the uniformity correction system using the thermal state criterion during lithographic exposure of a substrate. 16. A method for controlling a radiation beam for lithography, Adjusting the aforementioned radiation beam, Adjusting the intensity profile of the radiation beam based at least partially on a thermal state criterion that indicates the heat generated by the radiation beam, A method that includes this. 17. Comparing the aforementioned thermal state criterion with a reference thermal state criterion, Adjusting the intensity profile of the radiation beam based at least partially on the aforementioned comparison, The method described in item 16, including the method described in item 16. 18. The method according to paragraph 17, wherein the reference thermal state criterion includes a predetermined limit, and the method includes adjusting the intensity profile of the radiated beam when the thermal state criterion reaches the predetermined limit. 19. The thermal condition criterion is the method described in any of items 16 to 18, including a predictive component. 20. The method according to paragraph 19, wherein the prediction component is calculated at least in part based on predetermined lithography exposure information. 21. The thermal condition criterion is the method described in any one of items 16 to 20, including the component under monitoring. 22. The method according to item 21, wherein the monitored component includes temperature measurements and / or thermal deformation measurements. 23. The monitored component is the method described in Section 21 or 22, including lithography exposure information. 24. Determining the relationship between the intensity profile of the radiation beam and the thermal state criterion, Using the above relationship, determine the reference thermal state criterion, Adjusting the intensity profile of the radiated beam based at least partially on the aforementioned reference thermal state criteria, The method described in any of paragraphs 16 to 23, including the method described in any of paragraphs 16 to 23. 25. A method for projecting a patterned radiation beam onto a substrate, including the method described in any of sections 16 to 24. 26. A computer program that includes computer-readable instructions configured to cause a computer to perform any of the methods described in paragraphs 16 to 25. 27. A computer-readable medium carrying the computer program described in paragraph 26. 28. Memory for storing processor-readable instructions, A processor configured to read and execute instructions stored in the aforementioned memory, Equipped with, A computer device comprising a processor-readable instruction set up to control the computer to perform the method described in any of paragraphs 16 to 25.

[0088] While this specification specifically refers to the use of lithography equipment in the manufacture of ICs, it should be understood that the lithography equipment described herein may have other applications. Other applications include the manufacture of integrated optical systems, induction and detection patterns for magnetic domain memory, flat panel displays, liquid crystal displays (LCDs), and thin-film magnetic heads.

[0089] While embodiments of the present invention may be specifically referenced in relation to lithography apparatus, embodiments of the present invention can also be used in other apparatuses. Embodiments of the present invention can form part of a mask inspection apparatus, a measuring apparatus, or any apparatus for measuring or processing objects such as wafers (or other substrates) or masks (or other patterning devices). These apparatuses are sometimes commonly referred to as lithography tools. Such lithography tools may operate under vacuum conditions or ambient (non-vacuum) conditions.

[0090] Where circumstances permit, embodiments of the present invention may be implemented in hardware, firmware, software, or any combination thereof. Embodiments of the present invention may also be implemented as instructions stored in a machine-readable medium, which may be read and executed by one or more processors. A machine-readable medium may include any mechanism for storing or transmitting information in a format readable by a machine (e.g., a computing device). For example, machine-readable media may include read-only memory (ROM), random-access memory (RAM), magnetic storage media, optical storage media, flash memory devices, electrical, optical, acoustic, or other forms of propagating signals (such as carrier waves, infrared signals, or digital signals). Furthermore, firmware, software, routines, and instructions may be described herein as performing specific operations. However, such descriptions are merely for convenience, and it should be understood that such operations actually originate from computing devices, processors, controllers, or other devices that execute firmware, software, routines, instructions, etc., in which actuators or other devices may interact with the physical world.

[0091] While specific embodiments of the present invention have been described above, it will be understood that the present invention may be implemented in ways different from those described. The above descriptions are illustrative and not limiting. Therefore, those skilled in the art will understand that modifications to the invention described above may be made without departing from the scope of the claims described below. Each feature disclosed or illustrated herein can be incorporated into any embodiment, either alone or in appropriate combination with other features disclosed or illustrated herein.

Claims

1. A lithography device, A lighting system configured to adjust the radiation beam, A uniformity correction system configured to adjust the intensity profile of the radiation beam, A control system configured to control the uniformity correction system based at least partially on a thermal state criterion that indicates a part of the thermal state of the lithography apparatus, A measurement system configured to measure the thermal deformation of a portion of the lithography apparatus, wherein the thermal state criterion includes a component to be monitored, and the component to be monitored includes measurements performed by the measurement system, A detection system configured to measure the temperature of a part of the lithography apparatus, wherein the monitored component includes a measurement performed by the detection system, A support device configured to hold a patterning device, wherein the patterning device is configured to give a pattern to the cross-section of the radiation beam to form a patterned radiation beam; A reticle masking blade system configured to selectively block the patterned radiation beam, wherein the sensing system is configured to measure the temperature of the support device and / or the reticle masking blade system, A lithography apparatus equipped with [a specific feature].

2. The lithography apparatus according to claim 1, wherein the control system is configured to control the uniformity correction system at least in part based on a comparison between the thermal state criterion and a reference thermal state criterion.

3. The lithography apparatus according to claim 2, wherein the reference thermal state criterion includes a predetermined limit, and the control system is configured to cause the uniformity correction system to adjust the intensity profile of the radiated beam when the thermal state criterion reaches the predetermined limit.

4. The lithography apparatus according to any one of claims 1 to 3, wherein the thermal state criterion includes a predictive component.

5. The lithography apparatus according to claim 4, wherein the prediction component is calculated at least in part based on predetermined lithography exposure information.

6. A lithography apparatus according to any one of claims 1 to 5, comprising a cooling system configured to provide a flow of coolant for cooling a portion of the lithography apparatus, wherein the sensing system is configured to measure the temperature of the coolant.

7. An optical device configured to interact with the aforementioned radiation beam, A support structure configured to support the optical element, Equipped with, The lithography apparatus according to any one of claims 1 to 6, wherein the detection system is configured to measure the temperature of the optical element and / or the support structure.

8. A lithography apparatus, A lighting system configured to adjust the radiation beam, A uniformity correction system configured to adjust the intensity profile of the radiation beam, A control system configured to control the uniformity correction system based at least partially on a thermal state criterion that indicates a part of the thermal state of the lithography apparatus, A measurement system configured to measure the thermal deformation of a portion of the lithography apparatus, wherein the thermal state criterion includes a component to be monitored, and the component to be monitored includes measurements performed by the measurement system, Equipped with, The aforementioned measurement system is A reflective surface configured to reflect at least a portion of the radiation beam, and an arm extending from the surface opposite to the reflective surface, The system comprises a support frame on which a detection device is provided, configured to measure the gap between the detection device and the arm, The monitored component includes a lithography apparatus with a gap measured by the measurement system.

9. The aforementioned measurement system is A reflector configured to reflect at least a portion of the aforementioned radiation beam, The system includes a sensor configured to measure the position of the reflective portion of the radiation beam, The lithography apparatus according to claim 8, wherein the monitored component includes the position of the reflective portion of the radiation beam measured by the measurement system.

10. The lithography apparatus according to any one of claims 1 to 9, wherein the monitored component includes lithography exposure information.

11. The lithography apparatus according to any one of claims 1 to 10, wherein the control system is configured to control the uniformity correction system using the thermal state criterion during lithographic exposure of a substrate.

12. A method for controlling the radiation beam of a lithography apparatus, Adjusting the aforementioned radiation beam, Adjusting the intensity profile of the radiated beam at least partially based on a thermal state criterion that indicates the thermal state of a part of the lithography apparatus, wherein the thermal state criterion includes a monitored component, and the monitored component includes thermal deformation measurements. The measurement of the temperature of a part of the lithography apparatus using a detection system, wherein the monitored component includes the measurement value performed by the detection system. A support device is used to hold a patterning device, wherein the patterning device is configured to give a pattern to the cross-section of the radiation beam to form a patterned radiation beam. A reticle masking blade system is used to selectively block the patterned radiation beam, wherein the sensing system is configured to measure the temperature of the support device and / or the reticle masking blade system. Methods that include...

13. The thermal state criteria are compared with a reference thermal state criteria, Adjusting the intensity profile of the radiation beam based at least partially on the aforementioned comparison, The method according to claim 12, including the method described in claim 12.

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