Method and computing device for compensating liquid-transmitted acoustic disturbances of a liquid-tempered optical component of a lithography system, compensation system, lithography system, and method for producing a control device

Abstract

Method for compensating liquid-transmitted acoustic disturbances of a liquid-tempered optical component (110) of a lithography system (1), wherein the disturbances of the optical component (110) as a first optical component (110) are compensated by means of a non-liquid-tempered second optical component (112) of the lithography system (1), comprising the steps: a) Receiving (S1) a first and second actual value (y 1 , y 2 ) of a position (P 1 , P 2 ) corresponding to the first and second optical components (110, 112), and b) Rules (S3) of the position (P 2 ) of the second optical component (112) to an adjusted target value (r 2 ) of the position (P 2 ) of the second optical component (112), which is set to an initial target value (r i ) of the position (P 2) of the second optical component (112) and the first actual value (y 1 ) of the position (P 1 ) of the first optical component (110).

Description

[0001] The present invention relates to a method and a computing device for compensating liquid-transmitted acoustic disturbances of a liquid-tempered optical component of a lithography system, a compensation system and a lithography system with such a computing device and a method for producing a controller device for controlling a position of a liquid-tempered optical component of a lithography system.

[0002] Microlithography is used to manufacture microstructured components, such as integrated circuits. The microlithography process is carried out using a lithography system equipped with an illumination system and a projection system. The image of a mask (reticle) illuminated by the illumination system is projected by the projection system onto a substrate, such as a silicon wafer, coated with a light-sensitive layer (photoresist) and arranged in the image plane of the projection system in order to transfer the mask structure to the light-sensitive coating of the substrate.

[0003] Driven by the pursuit of ever smaller structures in the production of integrated circuits, EUV lithography systems are currently being developed that use light with a wavelength in the range of 0.1 nm to 30 nm, particularly 13.5 nm. Since most materials absorb light at this wavelength, such EUV lithography systems must use reflective optics, i.e., mirrors, instead of the previously used refractive optics, i.e., lenses.

[0004] The demands on the accuracy and precision of the imaging properties of lithography systems are constantly increasing. From a dynamic perspective, it is therefore important to minimize the influence of interference on the movement of various components of the lithography system. For example, very precise positioning of optical components, especially mirrors, and mechanical components, especially sensor frames, of the lithography system is required. Dynamic interference excitations of optical and mechanical components can be generated, for example, by the movement of other components of the lithography system. Furthermore, due to increasing thermal requirements, it is necessary to cool optical and mechanical components of the lithography system, especially mirrors and sensor frames. For cooling, a cooling device with cooling lines is necessary, through which a coolant is transported to the component to be cooled.This leads to another source of dynamic disturbance excitation in the form of acoustic disturbances. Acoustic disturbances are transmitted, for example, as longitudinal waves through the coolant in the cooling lines to the component to be cooled.

[0005] Against this background, it is an object of the present invention to provide an improved method and an improved computing device for compensating liquid-transmitted acoustic disturbances of a liquid-tempered optical component of a lithography system.

[0006] According to a first aspect, a method for compensating liquid-transmitted acoustic disturbances of a liquid-tempered optical component of a lithography system is proposed. The disturbances of the optical component as a first optical component are compensated using a non-liquid-tempered second optical component of the lithography system. The method comprises the following steps: a) receiving a first and second actual value of a position corresponding to the first and second optical components, and b) controlling the position of the second optical component to an adjusted target value of the position of the second optical component, which is based on an initial target value of the position of the second optical component and the first actual value of the position of the first optical component.

[0007] Consequently, the position of the second optical component is controlled to a target position, which includes the actual position of the first optical component. A position error of the liquid-tempered first optical component is thus forwarded to a control loop of the non-liquid-tempered second optical component. The control loop of the non-liquid-tempered second optical component consequently corrects the position errors of both the first and the second optical component. The proposed control architecture thus makes it possible to at least partially compensate for a position error of the liquid-tempered first optical component due to liquid-transmitted acoustic disturbances by controlling the position of the second optical component.

[0008] In particular, a position error of the first optical component can lead to an imaging error of the first optical component. This imaging error is compensated for by the proposed position control of the second optical component, which changes the imaging properties of the second optical component.

[0009] The adjusted target value of the position of the second optical component is, for example, a sum of the initial target value of the position of the second optical component and the first actual value of the position of the first optical component. The initial target value of the position of the second optical component is, in particular, a target value for the position of the second optical component that corresponds to the desired value for the position of the second optical component in a case in which a position error of the first optical component is not corrected or the position error of the first optical component is zero.

[0010] Acoustic disturbances are transmitted via fluid sound waves (i.e., pressure waves or pressure fluctuations, e.g., longitudinal waves) of the fluid in the fluid lines to fluid-temperature-controlled components, such as the first optical component. For example, the first optical component is mechanically connected to one or more fluid lines to transport the fluid to and from the first optical component. This results in a force transfer to the first optical component at the surfaces of the first optical component that are impacted by the pressure fluctuations.

[0011] Acoustic disturbances can be caused by flow-induced vibrations (FIV) in the fluid. Flow-induced vibrations are generated, for example, by pumps, valves, pipe deflections, and changes in pipe cross-section (so-called "FIV sources"). Acoustic disturbances can also be transmitted to the fluid by mechanical vibrations from other components via support elements of the fluid lines.

[0012] If pressure fluctuations occur in a fluid line used to control the temperature (e.g., cool) of an optical component, the position of the optical component can be undesirably altered by the acoustic disturbances. This leads to an aberration of the optical component and thus of the lithography system. Position control of the liquid-temperature-controlled first optical component can lead to superposition of the resonances of the disturbance excitation and the transfer function of the controller used, especially with conventional controller architectures.

[0013] Since the second optical component is not liquid-tempered, it is not subject to fluid-borne acoustic disturbances. Thus, the actuators of the second optical component can advantageously be used to compensate for position changes of the first optical component indirectly (namely, via the position change of the second optical component).

[0014] The lithography system is, for example, an EUV or DUV lithography system. EUV stands for "extreme ultraviolet" (EUV) and refers to a wavelength of the working light in the range of 0.1 nm to 30 nm, specifically 13.5 nm. Furthermore, DUV stands for "deep ultraviolet" (DUV) and refers to a wavelength of the working light between 30 nm and 250 nm.

[0015] The EUV or DUV lithography system comprises an illumination system and a projection system. In particular, the EUV or DUV lithography system projects the image of a mask (reticle) illuminated by the illumination system onto a substrate coated with a light-sensitive layer (photoresist) and arranged in the image plane of the projection system, for example, a wafer and / or silicon wafer, using the projection system to transfer the mask structure to the light-sensitive coating of the substrate.

[0016] The lithography system has, for example, a temperature control device (e.g. cooling device) which comprises one or more liquid lines for transporting a temperature control liquid (e.g. cooling liquid, such as water) to the first optical component.

[0017] The first and / or second optical component is, for example, a mirror of the lithography system. The first and / or second optical component is, for example, an optical component of a projection system of the lithography system. The first and / or second optical component is, in particular, a component that must be held in a precise position with only small tolerances during operation of the lithography system.

[0018] A cooling device of the lithography system is configured, for example, to cool the first optical component of the lithography system. The second optical component, however, is an untemperatured, e.g., uncooled, optical component. The cooling device can also be configured, for example, to cool other optical and / or mechanical components of the lithography system—with the exception of the second optical component. The cooling device serves in particular to prevent high temperatures and temperature fluctuations of the first optical component (and possibly other components to be cooled). In particular, mirrors of an EUV lithography system (as an example of a first optical component) heat up as a result of absorption of the high-energy EUV radiation. The resulting high temperatures and temperature fluctuations in the mirror and the associated thermal deformation of the mirror can lead to wavefront aberrations and thus impair the imaging properties of the mirrors. To avoid thermally induced deformations, optical components of the lithography system are actively cooled.

[0019] The temperature control device (e.g., cooling device) comprises, for example, a temperature control unit (e.g., cooling unit) for controlling the temperature (e.g., cooling) of the liquid. The temperature control device comprises one or more liquid lines for transporting the liquid. The liquid line(s) is / are made of metal, such as stainless steel, for example. The temperature control device also comprises one or more pumps for generating a required flow rate of the liquid in the line and one or more valves for controlling the flow through the line.

[0020] The temperature control device can be a cooling device for cooling the first optical component or a heating device for heating the first optical component.

[0021] According to an embodiment of the first aspect, the method comprises a step of controlling the position of the first optical component to a first target value of the position of the first optical component based on the first actual value.

[0022] In this embodiment, in addition to controlling the position of the second optical component, the position of the first optical component is also controlled. Since the first optical component is liquid-temperature-controlled and thus subject to acoustic disturbances, a control error when controlling the position of the first optical component can be relatively large. The (e.g., remaining) control error when controlling the position of the first optical component is then at least partially compensated by the adjusted target value when controlling the position of the second optical component.

[0023] According to a further embodiment of the first aspect, controlling the position of the first optical component comprises: Determining a first manipulated variable based on a first deviation of the first actual value from the first setpoint, and Controlling a first actuator device for positioning the first optical component based on the first manipulated variable.

[0024] This allows the position of the first optical component to be controlled using feedback control. In particular, the first actual position is fed back to determine the first deviation.

[0025] The first actuator device is configured, for example, to adjust the position of the first optical component with respect to six degrees of freedom of the first optical component. The six degrees of freedom include, in particular, three translational degrees of freedom (in three spatial directions spanning a three-dimensional space) and three rotational degrees of freedom (with respect to a rotation around the three spatial directions).

[0026] According to a further embodiment of the first aspect, controlling the position of the second optical component comprises: Determining a second manipulated variable based on a second deviation of the second actual value from the adjusted setpoint, and Controlling a second actuator device for positioning the second optical component based on the second manipulated variable.

[0027] This allows the position of the second optical component to be controlled using feedback control. In particular, the second actual position is fed back to determine the second deviation.

[0028] The second actuator device is configured, for example, to adjust the position of the second optical component with respect to six degrees of freedom of the second optical component. The six degrees of freedom include, in particular, three translational degrees of freedom (in three spatial directions spanning a three-dimensional space) and three rotational degrees of freedom (with respect to a rotation around the three spatial directions).

[0029] For example, the following relationships apply to controlling the position of the first and / or second optical component. The first or second manipulated variable is determined based on an actual value-setpoint deviation of the position of the corresponding optical component. This enables position control based on feedback of the measured current value (i.e., the first or second actual value) of the position of the corresponding optical component. The first or second actual value of the position of the corresponding optical component is measured, for example, and fed back to an input of a corresponding position controller device.

[0030] The first setpoint value for the position of the first optical component and / or the initial setpoint value for the position of the second optical component is, for example, a static value, so that the position of the corresponding optical component is controlled to a rest position according to the static value. However, the first or initial setpoint value for the position of the corresponding optical component can also change over time, so that the goal of the corresponding control is for the position of the corresponding optical component to follow a predetermined time-dependent path (trajectory).

[0031] The first or second deviation (ie the corresponding control deviation) is determined in particular by negatively adding (subtracting) the first or second actual value to the first or adjusted setpoint.

[0032] The first and / or second manipulated variable is determined in particular such that the current position of the corresponding optical component (controlled variable) is adapted to the first or adjusted setpoint (reference variable). The first or second manipulated variable is in particular a measure of a position change to be applied to the corresponding optical component by means of the first or second actuator device.

[0033] According to a further embodiment of the first aspect, the control of the position of the first optical component takes place in a first pre-determined control frequency range which is different from a pre-determined interference frequency range of the acoustic interference excitations of the first optical component.

[0034] This allows the control frequency range for controlling the position of the first optical component to be preset to a frequency range in which acoustic disturbances are low and / or nonexistent. Consequently, resonance transmissions from disturbances and the controller's transfer function can be avoided or reduced.

[0035] The fact that the first pre-determined control frequency range is different from the pre-determined interference frequency range means, for example, that the first pre-determined control frequency range and the pre-determined interference frequency range do not overlap, are disjoint and / or (e.g. directly) adjoin each other.

[0036] For example, an upper limit frequency of the first pre-determined control frequency range is less than or equal to a lower limit frequency of the pre-determined interference frequency range.

[0037] For example, a lower limit frequency of the first pre-determined control frequency range is greater than or equal to an upper limit frequency of the pre-determined interference frequency range.

[0038] For example, the pre-determined interference frequency range is 1 to 60 Hz, 60 to 150 Hz and / or 80 to 200 Hz.

[0039] For example, the first pre-determined control frequency range is 60 to 120 Hz and the pre-determined interference frequency range is 1 to 60 Hz. For example, the first pre-determined control frequency range is 40 to 80 Hz and the pre-determined interference frequency range is 80 to 200 Hz. For example, the first pre-determined control frequency range is 1 to 40 Hz or 1 to 60 Hz and the pre-determined interference frequency range is 60 to 150 Hz.

[0040] A main source of mechanical vibrations in the lithography system is, for example, a mask holder (reticle stage) and a substrate holder (wafer stage) of the lithography system. The mask holder is used to support and move a mask to be imaged. Furthermore, the substrate holder is used to support and move a substrate on which an image of the mask is imaged. Mechanical vibrations of the lithography system can be transmitted via support elements to fluid lines for tempering (e.g., cooling) the first optical component. Vibrations in the form of acoustic vibrations are transmitted to the first optical component via the fluid in the fluid lines. The interference excitations from the mask holder (reticle stage) and the substrate holder (wafer stage), for example, have high amplitudes at frequencies in the range of 60 to 150 Hz. In this case, the pre-determined interference frequency range is, for example, 60 to 150 Hz.Furthermore, in this case, the control frequency range for controlling the position of the first optical component is preset to a frequency range lower than 60 to 150 Hz. For example, the control frequency range for controlling the position of the first optical component is preset to a range of less than or equal to 40 Hz (e.g., 1 Hz to 40 Hz).

[0041] The first control frequency range and / or the interference frequency range is / are determined, for example, before the lithography system is first put into operation and / or before a control device for controlling the position of the first optical component is manufactured.

[0042] The pre-determined interference frequency range is determined, for example, using acceleration sensors in three (e.g., mutually perpendicular) spatial directions. The acceleration sensors are attached, for example, to the first optical component and / or a frame (e.g., support) of the first optical component in order to detect the interference excitation at the location of the first optical component.

[0043] According to a further embodiment of the first aspect, the first pre-determined control frequency range is a frequency range in which the first deviation is less than 10%, less than 5%, less than 3%, less than 1%, less than 0.1% and / or less than 0.01% of the first setpoint.

[0044] According to a further embodiment of the first aspect, the position of the first optical component is controlled in a pre-determined first control frequency range, the position of the second optical component is controlled in a pre-determined second control frequency range, and the first and second control frequency ranges are different from one another.

[0045] This allows the two control devices to be designed to adapt to position disturbances that occur for a liquid-tempered optical component and a non-liquid-tempered optical component.

[0046] The fact that the first and second control frequency ranges are different from each other means, for example, that the first and second control frequency ranges have different widths and / or that the first control frequency range is smaller than the second control frequency range.

[0047] For example, the first and second control frequency ranges overlap (e.g. partially) and / or the first control frequency range is a sub-range of the second control frequency range.

[0048] The second pre-determined control frequency range is, for example, a frequency range in which the second deviation is less than 10%, less than 5%, less than 3%, less than 1%, less than 0.1% and / or less than 0.01% of the second setpoint.

[0049] According to a further embodiment of the first aspect: the position of the first optical component and / or the second optical component is controlled by means of a control device which has at least one proportional control element, at least one integral control element and at least one derivative control element, and / or the pre-determined first control frequency range for controlling the position of the first optical component is preset by increasing the number of integral control elements of the control device.

[0050] For example, the position of the first optical component is controlled using a first control device. Furthermore, the position of the second optical component is controlled, for example, using a second control device.

[0051] The respective controller device has, for example, a controller unit (e.g., a software unit) and a controller component (e.g., a hardware component). Furthermore, the respective controller component has, for example, at least one proportional controller element, at least one integral controller element, and at least one derivative controller element.

[0052] The first and / or second controller device comprises, for example, a PID controller (i.e., a controller with exactly one proportional controller element, exactly one integral controller element, and exactly one derivative controller element).

[0053] Alternatively, in the first controller device, the number of integral controller elements of the controller device can be increased compared to the number of proportional controller elements and derivative controller elements. For example, the first controller device comprises a PI3D controller (i.e., with exactly one proportional controller element, three integral controller elements, and exactly one derivative controller element).

[0054] By increasing the number of integral control elements of the first control device for controlling the position of the first optical component, the first control frequency range can be shifted to lower frequencies. This allows the first control frequency range for controlling the position of the liquid-temperature-controlled first optical component to be shifted to a frequency range in which interference excitations are low and / or non-existent. This allows resonance transmissions to be avoided even more effectively.

[0055] According to a further embodiment of the first aspect: the first and second optical components are arranged consecutively with respect to a beam path of the lithography system, the first and second optical components are both arranged in an imaging beam path of the lithography system, the first and second optical components are both components of a projection system of the lithography system, and / or the first and second optical components are both configured to image a mask on a substrate arranged in an image plane of the lithography system and / or the projection system of the lithography system.

[0056] The first and second optical components are thus arranged such that they are part of the same optical system, in which a beam path is relayed between several optical elements. Consequently, rays that have already passed through the first optical component (e.g., reflected by it) or vice versa impinge on the second optical component.

[0057] The fact that the first and second optical components are arranged consecutively with respect to a beam path of the lithography system includes, for example, the case where they are arranged directly one after the other. In an arrangement directly one after the other, no further optical elements (e.g., mirrors) are arranged between the first and second optical components with respect to the beam path.

[0058] However, the fact that the first and second optical components are arranged consecutively with respect to a beam path of the lithography system can also include, for example, the case that further optical elements (e.g. mirrors) are arranged between the first and second optical components with respect to the beam path.

[0059] According to a further embodiment of the first aspect, the method comprises a step of regulating the pressure of a liquid in a liquid line configured for controlling the temperature of the liquid in the first optical component. An actual pressure value of the liquid pressure is received, a further manipulated variable is determined based on a pressure deviation of the actual pressure value from a desired pressure value, and a further actuator device of a pressure-changing device is controlled based on the determined further manipulated variable to change the pressure of the liquid in the liquid line.

[0060] This allows pressure fluctuations in the fluid to be actively suppressed. In particular, a pressure fluctuation in the fluid can be compensated before it is passed on to the first optical component to be tempered (e.g., cooled). This allows a position change of the first optical component caused by pressure fluctuations in the fluid to be reduced or avoided.

[0061] For example, the pressure setpoint is zero. However, the pressure setpoint can also have a different preset value other than zero.

[0062] The pressure of the liquid in the liquid line is controlled in particular in such a way that the pressure deviation of the actual pressure value from the setpoint pressure value is kept as small as possible.

[0063] For example, the pressure-changing device comprises an expansion chamber fluidically connected to a fluid line for receiving the fluid. The expansion chamber also includes means for changing the volume of the expansion chamber. Thus, the pressure of the fluid can be changed by changing the volume of the expansion chamber.

[0064] According to a further embodiment of the first aspect, the position of the first optical component is controlled in a pre-determined first control frequency range, the pressure of the liquid in the liquid line is controlled in a pre-determined further control frequency range, and the first and the further control frequency range are different from one another.

[0065] Thus, the pressure control is carried out in such a way that pressure fluctuations are compensated at the frequencies at which the control of the position of the first optical component does not work well (ie control errors are large).

[0066] For example, the further pre-determined control frequency range is a frequency range in which the pressure deviation is less than 10%, less than 5%, less than 3%, less than 1%, less than 0.1% and / or less than 0.01% of the pressure setpoint.

[0067] According to a second aspect, a computing device for compensating liquid-borne acoustic disturbances of a liquid-tempered optical component of a lithography system is proposed. The disturbances of the optical component as a first optical component are compensated using a non-liquid-tempered second optical component of the lithography system. The computing device comprises: a receiving unit for receiving a first and second actual value of a position corresponding to the first and second optical components, and a controller unit for controlling the position of the second optical component to an adjusted setpoint value of the position of the second optical component, which is based on an initial setpoint value of the position of the second optical component and the first actual value of the position of the first optical component.

[0068] In embodiments, the controller unit for controlling the position of the second optical component is a second controller unit. Furthermore, the computing device has a first controller unit for controlling a position of the first optical component.

[0069] In embodiments, the computing device comprises a first and / or second control device for controlling a first or second actuator device based on the first or second determined manipulated variable, respectively.

[0070] According to a third aspect, a compensation system for compensating liquid-borne acoustic disturbances of a liquid-tempered optical component of a lithography system is proposed. The disturbances of the optical component as a first optical component are compensated using a non-liquid-tempered second optical component of the lithography system. The compensation system comprises: the liquid-tempered first optical component, the non-liquid-tempered second optical component, an actuator device for adjusting a position of the second optical component, and a computing device as described above for determining a manipulated variable based on a deviation of the second actual value from the adjusted target value, and for controlling the actuator device for positioning the second optical component based on the manipulated variable.

[0071] The manipulated variable according to the third aspect corresponds in particular to the second manipulated variable described above. Furthermore, the deviation according to the third aspect corresponds in particular to the second deviation described above. Furthermore, the actuator device according to the third aspect corresponds in particular to the second actuator device described above.

[0072] According to a fourth aspect, a lithography system, in particular an EUV lithography system, is proposed. The lithography system comprises a computing device as described above or a compensation system as described above.

[0073] According to a fifth aspect, a method for manufacturing a control device for controlling a position of a liquid-temperature-controlled optical component of a lithography system is proposed. The method comprises the steps: Determining a noise frequency range of acoustic noise excitations of the optical component, and Setting up a control component of the control device such that the control of the position of the optical component takes place in a pre-determined control frequency range which is different from the pre-determined interference frequency range.

[0074] The method is used in particular for producing the above-described first control device for controlling the position of the above-described liquid-temperature-controlled first optical component of the lithography system. The pre-determined control frequency range corresponds, for example, to the above-described first pre-determined control frequency range.

[0075] Setting up the controller component of the controller device is, for example, setting up a controller hardware component of the controller device.

[0076] The respective computing device, receiving unit, controller unit, and control device described above or below, and other units, devices, and apparatuses described herein, can be implemented in hardware and / or software. In a hardware implementation, the respective unit can be configured, for example, as a computer or a microprocessor. In a software implementation, the respective unit can be configured as a computer program product, as a function, as a routine, as an algorithm, as part of a program code, or as an executable object. Furthermore, the corresponding unit can also be configured as part of a higher-level control system of the lithography system.

[0077] In this case, "one" is not necessarily limited to exactly one element. Rather, multiple elements, such as two, three, or more, may also be included. Any other counting term used here should also not be understood as implying a limitation to the exact number of elements stated. Rather, numerical deviations, both upward and downward, are possible unless otherwise stated.

[0078] The embodiments and features described for the method according to the first aspect apply accordingly to the second to fifth aspects and vice versa.

[0079] Further possible implementations of the invention also include combinations of features or embodiments described above or below with respect to the exemplary embodiments that are not explicitly mentioned. In this case, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.

[0080] Further advantageous embodiments and aspects of the invention are the subject of the dependent claims and the exemplary embodiments of the invention described below. The invention will be explained in more detail below using preferred embodiments with reference to the accompanying figures. Fig. 1 shows a schematic meridional section of a projection exposure system for EUV projection lithography; Fig. 2 shows a projection system and a compensation system of the projection exposure system of Fig. 1 according to a respective embodiment, wherein the compensation system is configured to compensate for liquid-transmitted acoustic disturbances of a liquid-tempered optical component of the projection system; Fig. 3 shows a first control device of the compensation system from Fig. 2 according to one embodiment; Fig. 4 shows a second control device of the compensation system from Fig. 2 according to one embodiment; Fig. 5 shows a flow diagram of a method for compensating liquid-borne acoustic disturbances of a liquid-tempered optical component of the projection system of Fig. 2 according to one embodiment; Fig. 6 shows a block diagram of a first and second control loop of the compensation system of Fig. 2 according to one embodiment; Fig. 7 shows a second control loop of the compensation system from Fig. 2 according to a further embodiment; Fig. 8 illustrates a frequency range of an acoustic disturbance excitation and several controller frequency ranges of the compensation system from Fig. 2 according to one embodiment; Fig. 9 shows a controller component of the first or second controller device from Fig. 3 and 4 respectively according to an embodiment; Fig. 10 shows a controller component of the first controller device from Fig. 3 according to another embodiment; Fig. 11 shows a third control loop of the compensation system from Fig. 2 according to one embodiment; and Fig. 12 shows a flowchart of a method for manufacturing a controller device of the compensation system from Fig. 2 for controlling a position of a liquid-tempered optical component of the projection system from Fig. 2.

[0081] In the figures, identical or functionally equivalent elements are provided with the same reference numerals unless otherwise stated. Furthermore, it should be noted that the representations in the figures are not necessarily to scale.

[0082] Fig. 1 shows an embodiment of a projection exposure system 1 (lithography system), in particular an EUV lithography system. One embodiment of an illumination system 2 of the projection exposure system 1 has, in addition to a light or radiation source 3, an illumination optics 4 for illuminating an object field 5 in an object plane 6. In an alternative embodiment, the light source 3 can also be provided as a separate module from the remaining illumination system 2. In this case, the illumination system 2 does not include the light source 3.

[0083] A reticle 7 arranged in the object field 5 is exposed. The reticle 7 is held by a reticle holder 8. The reticle holder 8 can be displaced via a reticle displacement drive 9, in particular in a scanning direction.

[0084] In the Fig. For illustrative purposes, Figure 1 shows a Cartesian coordinate system with an x-direction x, a y-direction y, and a z-direction z. The x-direction x runs perpendicular to the plane of the drawing. The y-direction y runs horizontally, and the z-direction z runs vertically. The scanning direction runs in the Fig. 1 along the y-direction y. The z-direction z runs perpendicular to the object plane 6.

[0085] The projection exposure system 1 comprises a projection optics 10. The projection optics 10 serves to image the object field 5 into an image field 11 in an image plane 12. The image plane 12 runs parallel to the object plane 6. Alternatively, an angle other than 0° between the object plane 6 and the image plane 12 is also possible.

[0086] A structure on the reticle 7 is imaged onto a light-sensitive layer of a wafer 13 arranged in the image plane 12 in the region of the image field 11. The wafer 13 is held by a wafer holder 14. The wafer holder 14 can be displaced, in particular along the y-direction y, via a wafer displacement drive 15. The displacement of the reticle 7, on the one hand, via the reticle displacement drive 9, and the displacement of the wafer 13, on the other hand, via the wafer displacement drive 15, can be synchronized with each other.

[0087] The light source 3 is an EUV radiation source. The light source 3 emits, in particular, EUV radiation 16, which is also referred to below as useful radiation, illumination radiation, or illumination light. The useful radiation 16 has, in particular, a wavelength in the range between 5 nm and 30 nm. The light source 3 can be a plasma source, for example an LPP source (Laser Produced Plasma) or a DPP source (Gas Discharged Produced Plasma). It can also be a synchrotron-based radiation source. The light source 3 can be a free-electron laser (FEL).

[0088] The illumination radiation 16 emanating from the light source 3 is focused by a collector 17. The collector 17 can be a collector with one or more ellipsoidal and / or hyperboloidal reflection surfaces. The at least one reflection surface of the collector 17 can be exposed to the illumination radiation 16 at grazing incidence (GI), i.e., at angles of incidence greater than 45°, or at normal incidence (NI), i.e., at angles of incidence less than 45°. The collector 17 can be structured and / or coated, on the one hand, to optimize its reflectivity for the useful radiation and, on the other hand, to suppress stray light.

[0089] After the collector 17, the illumination radiation 16 propagates through an intermediate focus in an intermediate focal plane 18. The intermediate focal plane 18 can represent a separation between a radiation source module, comprising the light source 3 and the collector 17, and the illumination optics 4.

[0090] The illumination optics 4 comprises a deflecting mirror 19 and, downstream of this in the beam path, a first facet mirror 20. The deflecting mirror 19 can be a flat deflecting mirror or, alternatively, a mirror with a beam-influencing effect beyond the pure deflection effect. Alternatively or additionally, the deflecting mirror 19 can be designed as a spectral filter that separates a useful light wavelength of the illumination radiation 16 from stray light of a different wavelength. If the first facet mirror 20 is arranged in a plane of the illumination optics 4 that is optically conjugated to the object plane 6 as the field plane, it is also referred to as a field facet mirror. The first facet mirror 20 comprises a plurality of individual first facets 21, which can also be referred to as field facets. Of these first facets 21, Fig. 1 only some examples are shown.

[0091] The first facets 21 can be designed as macroscopic facets, in particular as rectangular facets or as facets with an arcuate or partially circular edge contour. The first facets 21 can be designed as flat facets or, alternatively, as convexly or concavely curved facets.

[0092] As is known, for example, from DE 10 2008 009 600 A1, the first facets 21 themselves can also be composed of a plurality of individual mirrors, in particular a plurality of micromirrors. The first facet mirror 20 can, in particular, be designed as a microelectromechanical system (MEMS system). For details, reference is made to DE 10 2008 009 600 A1.

[0093] Between the collector 17 and the deflecting mirror 19, the illumination radiation 16 runs horizontally, i.e. along the y-direction y.

[0094] In the beam path of the illumination optics 4, a second facet mirror 22 is arranged downstream of the first facet mirror 20. If the second facet mirror 22 is arranged in a pupil plane of the illumination optics 4, it is also referred to as a pupil facet mirror. The second facet mirror 22 can also be arranged at a distance from a pupil plane of the illumination optics 4. In this case, the combination of the first facet mirror 20 and the second facet mirror 22 is also referred to as a specular reflector. Specular reflectors are known from US 2006 / 0132747 A1, EP 1 614 008 B1, and US Pat. No. 6,573,978.

[0095] The second facet mirror 22 comprises a plurality of second facets 23. In the case of a pupil facet mirror, the second facets 23 are also referred to as pupil facets.

[0096] The second facets 23 can also be macroscopic facets, which can, for example, be round, rectangular, or hexagonal, or alternatively facets composed of micromirrors. Reference is also made to DE 10 2008 009 600 A1 in this regard.

[0097] The second facets 23 may have planar or alternatively convex or concave curved reflection surfaces.

[0098] The illumination optics 4 thus form a double-faceted system. This basic principle is also known as a fly's-eye integrator.

[0099] It may be advantageous not to arrange the second facet mirror 22 exactly in a plane that is optically conjugate to a pupil plane of the projection optics 10. In particular, the second facet mirror 22 can be arranged tilted relative to a pupil plane of the projection optics 10, as described, for example, in DE 10 2017 220 586 A1.

[0100] With the help of the second facet mirror 22, the individual first facets 21 are imaged into the object field 5. The second facet mirror 22 is the last bundle-forming mirror or actually the last mirror for the illumination radiation 16 in the beam path before the object field 5.

[0101] In a further embodiment of the illumination optics 4 (not shown), a transmission optics can be arranged in the beam path between the second facet mirror 22 and the object field 5, which transmission optics contributes in particular to the imaging of the first facets 21 into the object field 5. The transmission optics can have exactly one mirror, but alternatively also two or more mirrors, which are arranged one behind the other in the beam path of the illumination optics 4. The transmission optics can in particular comprise one or two mirrors for normal incidence (NI mirrors, normal incidence mirrors) and / or one or two mirrors for grazing incidence (GI mirrors, grazing incidence mirrors).

[0102] The illumination optics 4 has in the version shown in the Fig. 1, after the collector 17 there are exactly three mirrors, namely the deflection mirror 19, the first facet mirror 20 and the second facet mirror 22.

[0103] In a further embodiment of the illumination optics 4, the deflection mirror 19 can also be omitted, so that the illumination optics 4 can then have exactly two mirrors after the collector 17, namely the first facet mirror 20 and the second facet mirror 22.

[0104] The imaging of the first facets 21 by means of the second facets 23 or with the second facets 23 and a transmission optics into the object plane 6 is usually only an approximate imaging.

[0105] The projection optics 10 comprises a plurality of mirrors Mi, which are numbered according to their arrangement in the beam path of the projection exposure system 1.

[0106] In the Fig. In the example shown in Figure 1, the projection optics 10 comprises six mirrors M1 to M6. Alternatives with four, eight, ten, twelve, or a different number of mirrors M1 are also possible. The projection optics 10 is a doubly obscured optic. The penultimate mirror M5 and the last mirror M6 each have a passage opening for the illumination radiation 16. The projection optics 10 has an image-side numerical aperture that is greater than 0.5 and can also be greater than 0.6, for example, 0.7 or 0.75.

[0107] Reflection surfaces of the mirrors Mi can be designed as freeform surfaces without a rotational symmetry axis. Alternatively, the reflection surfaces of the mirrors Mi can be designed as aspherical surfaces with exactly one rotational symmetry axis of the reflection surface shape. The mirrors Mi, like the mirrors of the illumination optics 4, can have highly reflective coatings for the illumination radiation 16. These coatings can be designed as multilayer coatings, in particular with alternating layers of molybdenum and silicon.

[0108] The projection optics 10 has a large object-image offset in the y-direction y between a y-coordinate of a center of the object field 5 and a y-coordinate of the center of the image field 11. This object-image offset in the y-direction y can be approximately as large as a z-distance between the object plane 6 and the image plane 12.

[0109] The projection optics 10 can, in particular, be anamorphic. It has, in particular, different magnifications βx, βy in the x and y directions x, y. The two magnifications βx, βy of the projection optics 10 are preferably (βx, βy) = (+ / - 0.25, + / - 0.125). A positive magnification B means imaging without image inversion. A negative sign for the magnification B means imaging with image inversion.

[0110] The projection optics 10 thus leads to a reduction in the ratio 4:1 in the x-direction x, i.e. in the direction perpendicular to the scanning direction.

[0111] The projection optics 10 leads to a reduction of 8:1 in the y-direction y, i.e. in the scanning direction.

[0112] Other magnifications are also possible. Magnifications with the same sign and absolutely identical in the x and y directions (x, y), for example, with absolute values ​​of 0.125 or 0.25, are also possible.

[0113] The number of intermediate image planes in the x- and y-directions x, y in the beam path between the object field 5 and the image field 11 can be the same or can be different depending on the design of the projection optics 10. Examples of projection optics with different numbers of such intermediate images in the x- and y-directions x, y are known from US 2018 / 0074303 A1.

[0114] Each of the second facets 23 is assigned to exactly one of the first facets 21 to form a respective illumination channel for illuminating the object field 5. This can, in particular, result in illumination according to the Köhler principle. The far field is divided into a plurality of object fields 5 using the first facets 21. The first facets 21 generate a plurality of images of the intermediate focus on the second facets 23 assigned to them.

[0115] The first facets 21 are each imaged onto the reticle 7 by an associated second facet 23, superimposed on one another, to illuminate the object field 5. The illumination of the object field 5 is, in particular, as homogeneous as possible. It preferably has a uniformity error of less than 2%. Field uniformity can be achieved by superimposing different illumination channels.

[0116] By arranging the second facets 23, the illumination of the entrance pupil of the projection optics 10 can be geometrically defined. By selecting the illumination channels, in particular the subset of the second facets 23 that guide light, the intensity distribution in the entrance pupil of the projection optics 10 can be adjusted. This intensity distribution is also referred to as the illumination setting or illumination pupil fill.

[0117] A likewise preferred pupil uniformity in the area of ​​defined illuminated sections of an illumination pupil of the illumination optics 4 can be achieved by redistributing the illumination channels.

[0118] Further aspects and details of the illumination of the object field 5 and in particular of the entrance pupil of the projection optics 10 are described below.

[0119] The projection optics 10 can, in particular, have a homocentric entrance pupil. This can be accessible. It can also be inaccessible.

[0120] The entrance pupil of the projection optics 10 cannot usually be precisely illuminated with the second facet mirror 22. When the projection optics 10 images the center of the second facet mirror 22 telecentrically onto the wafer 13, the aperture rays often do not intersect at a single point. However, a surface can be found in which the pairwise determined distance of the aperture rays is minimized. This surface represents the entrance pupil or a surface conjugate to it in spatial space. In particular, this surface exhibits a finite curvature.

[0121] It is possible that the projection optics 10 have different entrance pupil positions for the tangential and sagittal beam paths. In this case, an imaging element, in particular an optical component of the transmission optics, should be provided between the second facet mirror 22 and the reticle 7. With the help of this optical element, the different positions of the tangential entrance pupil and the sagittal entrance pupil can be taken into account.

[0122] At the Fig. In the arrangement of the components of the illumination optics 4 shown in Figure 1, the second facet mirror 22 is arranged in a surface conjugate to the entrance pupil of the projection optics 10. The first facet mirror 20 is arranged tilted relative to the object plane 6. The first facet mirror 20 is arranged tilted relative to an arrangement plane defined by the deflection mirror 19. The first facet mirror 20 is arranged tilted relative to an arrangement plane defined by the second facet mirror 22.

[0123] Fig. 2 shows an example of a projection system 100 with a projection optics 102 of the lithography system 1 from Fig. 1 according to one embodiment.

[0124] In Fig. 2, several exemplary frame structures (support structures) 104, 106, 108 of the projection system 100 are schematically illustrated. In addition, Fig. 1 shows a first optical component 110 and a second optical component 112 of the projection system 100. The first and second optical components 110, 112 are, for example, mirrors. For example, the mirrors 110, 112 are two of the mirrors M1 to M6 from Fig. 1. In the following, the first and second optical components 110, 112 are described as first and second mirrors 110, 112, without being limited thereto. Although in Fig. 2, the projection system 100 may also include further mirrors and / or optical components in addition to the first and second mirrors 110, 112.

[0125] The frame structure 108 is, for example, a sensor frame of the projection system 100. On the sensor frame 108, for example, a sensor device 114 is arranged, with which a current position P 1 , P 2 (Actual values ​​y 1 (t) and y 2(t) corresponding to the position P 1 , P 2 , see Fig. 6) of the first and second mirrors 110, 112 relative to the sensor frame 108 can be measured. The sensor device 114 is in Fig. 2 only schematically indicated. The sensor device 114 has one or more sensors, such as interferometers, attached to the sensor frame 108. For example, a current position y 1 (t) of the first mirror 110 and a current position y 2 (t) of the second mirror 112 using laser beams 116. For example, the current positions y 1 (t), y 2 (t) of the first and second mirrors 110, 112 with respect to six degrees of freedom. The six degrees of freedom include, in particular, three translational degrees of freedom in the x-, y- and z-directions in Fig. 2 and three rotational degrees of freedom around the x, y and z directions.

[0126] The reference number 106 in Fig. 2, for example, denotes a support frame (English: force frame) of the mirrors 110, 112. The mirrors 110, 112 are each movably attached to the support frame 106 by means of an actuator device 118, 120. Each of the first and second actuator devices 118, 120 has one or more actuators 122 for positioning the corresponding first and second mirrors 110, 112. For example, the mirrors 110, 112 can each be displaced in the six degrees of freedom by means of the actuators 122. The mirrors 110, 112 are also attached to the support frame 106 in a manner that is vibration-decoupled, for example.

[0127] In addition, the sensor frame 108 is also mounted in a vibration-decoupled manner, for example, with respect to the support frame 106. Furthermore, the support frame 106 is mounted in a vibration-decoupled manner, for example, with respect to a frame structure 104 and / or a floor.

[0128] In Fig. 2 also shows a temperature control device 200 for controlling the temperature of the first mirror 110. The temperature control device 200 is described below as a cooling device 200, by way of example, although the temperature control device 200 can also be used to heat the mirror 110 in other embodiments. The first mirror 110 is liquid-temperature-controlled (e.g., liquid-cooled) using the temperature control device 200. However, the second mirror 112 is not liquid-temperature-controlled (e.g., liquid-cooled). This circumstance is used below for advantageous compensation of liquid-transmitted acoustic interference excitations of the liquid-temperature-controlled first mirror 110.

[0129] Although in Fig. 2, the temperature control device 200 can also be used to temperature control other components of the projection system 100—with the exception of the second mirror 112—in addition to the first mirror 110. For example, the temperature control device 200 can also be configured to temperature control the sensor frame 108 or other mirrors not shown.

[0130] The cooling device 200 (as an example of a temperature control device 200) comprises a cooling unit 202 for cooling a cooling liquid 204. The cooling device 200 also comprises one or more liquid lines 206 for transporting the cooling liquid 204 from the cooling unit 202 to the component 110 to be cooled and back to the cooling unit 202. The cooling device 200 also comprises one or more pumps (not shown) for generating a required flow rate of the cooling liquid 204. The cooling device 200 further comprises one or more valves (not shown) for controlling the cooling flow.

[0131] In Fig. 2 also shows a compensation system 300 for compensating for fluid-borne acoustic disturbances of the fluid-tempered first mirror 110. The disturbances of the first mirror 110 are compensated for using the non-fluid-tempered second mirror 112. The compensation system 300 can be part of the projection system 100.

[0132] The compensation system 300 comprises the liquid-cooled first mirror 110 and the non-liquid-cooled second mirror 112. The compensation system 300 also comprises the second actuator device 120 for adjusting the position P 2 of the second mirror 112. The compensation system 300 can optionally also include a first actuator device 118 for adjusting the position P 1 of the first mirror 110.

[0133] The compensation system 300 also includes a computing device 302. The computing device 302 is connected to the sensor device 114 and the second actuator device 120 for (wireless or wired) data transmission 304. Optionally, the computing device 302 can also be connected, for example, to the first actuator device 118 for data transmission 304.

[0134] The computing device 302 has a receiving unit 306 for receiving the first actual value y 1 (t) of position P 1 of the first mirror 110 and the second actual value y 2 (t) of position P 2 of the second mirror.

[0135] The computing device 302 optionally has a control unit 308 (first control unit 308) for controlling the position P 1 of the first mirror 110. The computing device 302 also has a second control unit 310 for controlling the position P 2 of the second mirror 112.

[0136] The compensation system 300 can, as in Fig. 3 and Fig. 4 illustrates a first control device 312 for controlling the position P 1 of the first mirror 110 and / or a second control device 314 for controlling the position P 2 of the second mirror 110. The first controller device 312 comprises the controller unit 308, which is implemented, for example, as a software component. Furthermore, the first controller device 312 comprises a controller component 316, which is implemented, for example, as a hardware component. Similarly, the second controller device 314 comprises the controller unit 310, which is implemented, for example, as a software component, and a controller component 318, which is implemented, for example, as a hardware component.

[0137] In the following, with reference to Fig. 5 describes a method for compensating for liquid-transmitted acoustic disturbances of a liquid-tempered optical component (e.g., the first mirror 110) of a lithography system 1. The disturbances of the first optical component 110, e.g., the first mirror 110, are compensated for using a non-liquid-tempered second optical component 112, e.g., the second mirror 112, of the lithography system 1.

[0138] In a first step S1 of the method, a first actual value y 1 (t) of position P 1 of the first mirror 110. Furthermore, a second actual value y 2 (t) of position P 2 of the second mirror 112. The actual values ​​y 1 (t), y 2 (t) are detected, for example, by the sensor device 114 and transmitted via data transmission 304 to the receiving unit 306 of the computing device 302.

[0139] In an optional second step S2 of the method, a position P 1 of the first mirror 110 to a first target value r 1 (t) for position P 1 of the first mirror 110.

[0140] Fig. 6 shows a block diagram in which a control of the position P 1 of the first mirror 110 (control circuit R1). The control of the position P 1 of the first mirror 110 is based on feedback control. The feedback control is implemented by the controller 312 and a controlled system 320. The controlled system 320 includes an actuator 322 for manipulating the position P 1 of the first mirror 110. The actuator 322 is in particular by the first actuator device 118 ( Fig. 2). The controlled system 320 also includes a sensor 324 for measuring the current position y 1(t) of the first mirror 110. The sensor system 324 is in particular by the sensor device 114 ( Fig. 2). Furthermore, the controlled system 320 includes the first mirror 110.

[0141] The controller device 312, together with the controlled system 320, forms the feedback control in the control circuit R1 and ensures that a first deviation e 1 (t) of the first actual position y 1 (t) from a first target position r 1 (t) of the first mirror 110 is kept at the smallest possible value, ideally zero. The target position r 1 (t) can be a static value (r 1 (t) = const.) or can also be a function that depends on time t (r 1 (t) ≠ const.). In particular, the target position r 1 (t) of the first mirror 110 can also follow any (steady or discontinuous) trajectory in (e.g. three-dimensional) space.

[0142] The first received actual value y 1(t) is transmitted, ie fed back, from the receiving unit 306 to the first controller device 312, in particular the first controller unit 308. For example, the first actual value y 1 (t) is fed back to the control device 312 negatively (minus sign in Fig. 6).

[0143] In step S2, the first deviation e 1 (t) of the first actual value y 1 (t) from the first setpoint r 1 (t). The first deviation e 1 (t) is determined, for example, by the controller 312 or by an upstream summation unit 326. For example, the first actual value y 1 (t) from the first setpoint r 1 (t) is subtracted. To determine the first deviation e 1 (t) in the first controller device 312 or in the upstream summation unit 326, the first setpoint r 1 (t) deposited, in particular stored.

[0144] Furthermore, in step S2, a first manipulated variable u 1 (t) based on the first deviation e 1 (t) is determined.

[0145] Then, the first actuator device 118 is used to position the first mirror 110 based on the determined first manipulated variable u 2 (t) is controlled.

[0146] Since the first mirror 110 is liquid-tempered and thus subject to acoustic disturbances, a control error e 1 (t) when controlling the position P 1 of the first mirror 110 is relatively large. The control error of controlling the position P 1 of the first mirror 110 can be advantageously used when controlling the position P 2 of the second mirror 112 in step S3 is at least partially compensated.

[0147] In a third step S3 of the method, the position P 2 of the second mirror 112.

[0148] The block diagram in Fig. 6 illustrates in the lower part a control circuit R2 for controlling the position P 2 of the second mirror 112 in a feedback control.

[0149] Also when regulating the position P 2 of the second mirror 112 is - similar to the control of the position P 1 of the first mirror 110 - a second actual value y 2 (t) is fed back to the second controller 314 or a second summation unit 328. First, a second deviation e 2 (t) of the second actual value y 2 (t) from a setpoint r 2 (t) and based on the determined second deviation e 2 (t) a second manipulated variable u 2 (t). The second actuator device 120 is then used to position the second mirror 112 based on the second manipulated variable u 2 (t) is controlled.

[0150] Similar to the first control loop R1, the feedback control of the second control loop R2 is realized by the second controller 314 and a second controlled system 332. The controlled system 332 includes an actuator 334 for manipulating the position P 2 of the second mirror 112, which is in particular controlled by the second actuator device 120 ( Fig. 2). The second control system 332 also includes a sensor 336 for measuring the current position y 2 (t) of the second mirror 112. The sensor system 336 is in particular provided by the sensor device 114 ( Fig. 2). Furthermore, the controlled system 332 includes the second mirror 112.

[0151] The special feature of the regulation of position P 2 of the second mirror 112 (control circuit R2) is that for determining the second deviation e 2 (t) an adjusted setpoint r 2 (t) is applied, which is based on an initial setpoint ri (t) of the position (P 2 ) of the second mirror 112 and the first actual value y 1 (t) of position P 1 of the first mirror 112. In other words, the position P 2 of the second mirror 112 to a desired position r 2 (t) into which the actual position y 1 (t) of the first mirror 110.

[0152] In particular, in the embodiment of Fig. 6 the first actual value y 1 (t) of position P 1 of the first mirror 112 in the first control loop R1 is fed back to the first controller 312 or the summation unit 326. In addition, the first actual value y 1 (t) of position P 1 of the first mirror 112 to the second control loop R2. For example, the first actual value y 1 (t) as feedthrough setpoint r F(t) of the first mirror 110 to the second control loop R2, e.g. to a further summation unit 330 of the second control loop R2.

[0153] The adjusted setpoint r 2 (t) is calculated, for example, by summing the initial setpoint r i (t) and the first actual value y 1 (t) or the feedthrough setpoint r F (t) is determined: r2(t)=ri(t)+y1(t)=ri(t)+rF(t)

[0154] Thus, a position error of the liquid-tempered first mirror 110 due to liquid-transmitted acoustic disturbances can be forwarded to the control circuit R2 of the non-liquid-tempered second mirror 112. The control circuit R2 of the non-liquid-tempered second mirror 112 can consequently compensate for a position error of the liquid-tempered first mirror 110 by controlling the position P 2 of the second mirror 112 at least partially.

[0155] In Fig. Figure 7 is a block diagram relating to another embodiment of the method for compensating for fluid-borne acoustic disturbances of the fluid-tempered first mirror 110. In this embodiment, the position P 1 of the first mirror 110 is not regulated. The position P 2 of the second mirror 112 is controlled by means of a second control circuit R2' and a second control device 314'. The second control circuit R2' according to the embodiment in Fig. 7 differs from the second control circuit R2 according to the embodiment in Fig. 6 only by the fact that the first actual value y transmitted to the second control circuit R2 1 (t) an actual value y 1 (t) an uncontrolled position P 1 of the first mirror 110. That is, in the embodiment of Fig. 6, the second control circuit R2 is configured to compensate only for a remaining control error of the first mirror 110. In the embodiment of Fig. 7, however, the second control circuit R2' is set up to control the position P 1 of the first mirror 110 completely alone.

[0156] Since the first mirror 110 is liquid-cooled and thus affected by acoustic disturbances transmitted via the cooling liquid, superposition of the resonances of a disturbance excitation and a transfer function of the first control device 312 may occur. To avoid or reduce this, a control frequency range Δf 1 of the first control loop R1 (for example, during manufacture of the first control device 312).

[0157] In Fig. 8 is a frequency range Δf s a disturbance excitation is schematically illustrated. In particular, Fig. 8 shows a diagram which indicates an acceleration a (e.g., in one of the three spatial directions x, y, z) of the first mirror 110 as a function of a frequency f. A graph G shows a function of the acceleration a of the first mirror 110 as a function of the frequency f due to a disturbance excitation. As in Fig. 8, the acceleration a in a first frequency range Δf 1 of a frequency f 1 up to a frequency f 2 very low and / or zero (a 1 , a 2 ). Furthermore, an acceleration a with large amplitudes occurs in a second frequency range Δf 2 of a frequency f 2 up to a frequency f 3 The acceleration a of the first mirror 110 due to disturbance excitations can (although in Fig. 8 not shown) in all three spatial directions x, y, z. The acceleration a of the first mirror 110 due to disturbance excitations can be determined, for example, using acceleration sensors (not shown) attached to the first mirror 110 or a mirror body of the first mirror 110. Using the values ​​recorded by these sensors, a disturbance frequency range Δf S the acoustic disturbance excitations of the first mirror 110 are determined.

[0158] In order to avoid resonances in the control in control circuit R1 and the resulting position errors of the first mirror 110, the control of the position P 1 of the first mirror 110 in a pre-determined control frequency range Δf R1 which is determined by the interference frequency range Δf S is different. Only as an example, the range Δf 1 in Fig. 8 as a suitable control frequency range Δf R1For example, the first pre-determined control frequency range Δf R1 as a frequency range for which the control deviation e 1 (t) of the control loop R1 is less than 10%, less than 5%, less than 3%, less than 1%, less than 0.1% and / or less than 0.01% of the first setpoint r 1 (t) is.

[0159] In addition, the control of the position P 2 of the second mirror 112 by means of the second control loop R2 in a pre-determined second control frequency range Δf R2 which is determined from the first control frequency range Δf R1 Since the second mirror 112 is not liquid-cooled, it is not subject to acoustic interference, unlike the first mirror 110. Thus, avoiding the interference frequency range Δf S is not required for the second control loop R2. This allows the second control frequency range Δf R2be preset wider. In the example of Fig. 8, the second control frequency range Δf R2 Frequencies of f 1 to f 4 , where f 4 greater than the upper frequency limit f 2 of the first control frequency range Δf R1 is.

[0160] In Fig. 9 is an embodiment of the controller device 312, 314, in particular the controller component 316, 318 of the controller device 312, 314 ( Fig. 3 and Fig. 4). The corresponding controller component 316, 318 has at least one proportional controller element 338, at least one integral controller element 340 and at least one derivative controller element 342. The contributions to the manipulated variable u determined by the controller elements 338, 340, 342 1 (t) are combined at a further summation unit 344.

[0161] In the example of Fig. 9, the controller component 316, 318 has exactly one proportional controller element 338, exactly one integral controller element 340 and exactly one derivative controller element 342 (so-called PID controller).

[0162] In another in Fig. In the example shown in Figure 10, a controller component 316' of the first controller device 312' has a proportional controller element 338, three integral controller elements 340', and a derivative controller element 342 (so-called PI3D controller). By increasing the number of integral controller elements 342 of the controller device 312' for controlling the position P 1 of the first mirror 110, the first control frequency range Δf R1 be shifted to lower frequencies ( Fig. 8). This allows the first control frequency range Δf R1 for controlling the position P 1of the liquid-tempered first mirror 110 can be shifted into a frequency range in which interference excitations are low. Thus, resonance transmissions can be avoided even more effectively.

[0163] In an optional fourth step S4 of the method, a pressure D ( Fig. 2) the temperature control liquid 204 in the liquid line 206, which is designed for the liquid temperature control of the first mirror 110, is actively controlled.

[0164] In Fig. 11 illustrates a third control circuit R3 for controlling the pressure D of the tempering fluid 204 (e.g., cooling fluid 204). A pressure control device 400 comprises a third controller 402 and a third control system 404. The control system 404 comprises a sensor 406 for detecting an actual value y d(t) of the pressure D of the liquid 204, an actuator 408 for changing the pressure D of the liquid 204 (pressure changing device 410) and the liquid line 206.

[0165] In a feedback control, a detected actual value y d (t) of the pressure D of the liquid 204 is fed back to the third control device 402 or a summation unit 412. A pressure deviation e d (t) of the actual pressure value y d (t) from a pressure setpoint r d (t). The pressure setpoint r d (t) is, for example, zero. The third controller 402 then determines another manipulated variable u d (t) based on the pressure deviation e d (t). Based on the determined further control variable d u(t) then a further actuator device 408 of a pressure changing device 410 (e.g. an expansion chamber fluidly connected to the liquid line 206, not shown) is controlled to change the pressure D of the liquid 204 in the liquid line 206.

[0166] Through active pressure control, pressure fluctuations of the liquid 204 can be actively suppressed. In particular, a pressure fluctuation of the liquid 204 can be compensated before it is passed on to the first mirror 110 to be cooled. This allows a position change of the first mirror 110 caused by pressure fluctuations of the liquid 204 to be further reduced or avoided.

[0167] Optionally, the pressure D of the liquid 204 in the liquid line 206 can be controlled in a pre-determined further control frequency range Δf d ( Fig. 8). The pre-determined further control frequency range Δf dis chosen such that it is different from the first control frequency range Δf R1 in which the position control of the first mirror 110 takes place. As in Fig. 8, the further control frequency range Δf d and the first control frequency range Δf R1 Thus, the pressure control is carried out in such a way that pressure fluctuations are compensated at the frequencies at which the control of the position P 1 of the first mirror 110 has large control errors.

[0168] In the following, with reference to Fig. 12 a method for manufacturing a regulator device 312, 312' ( Fig. 3, Fig. 9 and Fig. 10) for controlling a position P 1 a liquid-tempered optical component 110 (first optical component 110, Fig. 2) a lithography system 1 ( Fig. 1) described.

[0169] In a first step S1' of the method, an interference frequency range Δf s ( Fig. 8) of acoustic disturbances of the optical component 110.

[0170] The interference frequency range Δf s of the acoustic interference excitations of the optical component 110 is in particular an interference frequency range Δf s the acoustic disturbance excitations of the optical component 110 during operation of the lithography system 1. During operation of the lithography system 1, the optical components are irradiated in particular with working light 6, e.g. EUV light, and / or a substrate holder (wafer holder 14 in Fig. 1) and / or a mask holder (reticle holder 8 in Fig. 1) moves.

[0171] In step S1' the interference frequency range Δf sof acoustic disturbance excitations of the optical component 110, for example by prediction (e.g. a model calculation) and / or by detection (e.g. by means of acceleration sensors).

[0172] In a second step S2' of the method, a controller component 316 of the controller device 312, 312' is set up (e.g. manufactured and / or adjusted) such that the control of the position P 1 of the optical component 110 in a pre-determined control frequency range Δf R1 which is determined from the pre-determined interference frequency range Δf s For example, the controller component 316 is set up such that the pre-determined control frequency range Δf R1 and the pre-determined interference frequency range Δf s do not overlap with each other.

[0173] Although the present invention has been described using exemplary embodiments, it can be modified in many ways. LIST OF REFERENCE SYMBOLS 1 projection exposure system 2 Lighting system 3 Light source 4 Lighting optics 5 Object field 6 Object level 7 reticles 8 reticle holders 9 Reticle displacement drive 10 Projection optics 11 Image field 12 Image plane 13 wafers 14 wafer holders 15 Wafer relocation drive 16 Illumination radiation 17 Collector 18 Intermediate focal plane 19 Deflecting mirrors 20 first facet mirror 21 first facet 22 second facet mirror 23 second facet 100 projection system 102 Projection optics 104 Frame structure 106 Frame structure 108 Frame structure 110 optical components 112 optical components 114 Sensor device 116 laser beam 118 Actuator device 120 actuator device 122 Actuator 200 Tempering device 202 Temperature control unit 204 Liquid 206 Liquid line 300 compensation system 302 Calculating device 304 Data transfer 306 receiving unit 308 control unit 310 control unit 312, 312' regulator device 314, 314' regulator device 316, 316' regulator component 318 Controller component 320 Control system 322 Actuators 324 Sensor technology 326 Summation unit 328 summation unit 330 summation unit 332 Control system 334 Actuators 336 Sensor technology 338 Control element 340, 340' regulator element 342 control element 344, 344' summation unit 400 pressure control device 402 Control device 404 Controlled system 406 Sensor technology 408 Actuator device (actuators) 410 Pressure change device 412 Summation unit a acceleration a 1 , a 2 , a 3 acceleration D pressure Δf 1 , Δf 2 Frequency range Δf R1 , Δf R2 Frequency range Δf s , Δf d Frequency range e 1 , e 2 , e d deviation f frequency f 1 , f 2 , f 3 , f 4 frequency GGraph M1-M6 mirrors P 1 , P 2 position r 1 , r 2 Setpoint r i , r F , r d Setpoint R1-R3, R2' control loop S beam path S1-S4 process steps S1'-S2' process steps t time and 1 , and 2 , and d Control value x, y, z direction y 1 , y 2 , y d Actual value 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 2008 009 600 A1 [0092, 0096] US 2006 / 0132747 A1

[0094] EP 1 614 008 B1

[0094] US 6,573,978

[0094] DE 10 2017 220 586 A1

[0099] US 2018 / 0074303 A1

[0113]

Claims

[1] Method for compensating liquid-transmitted acoustic disturbances of a liquid-tempered optical component (110) of a lithography system (1), wherein the disturbances of the optical component (110) as a first optical component (110) are compensated by means of a non-liquid-tempered second optical component (112) of the lithography system (1), comprising the steps: a) Receiving (S1) a first and second actual value (y 1 , y 2 ) of a position (P 1 , P 2 ) corresponding to the first and second optical components (110, 112), and b) Rules (S3) of the position (P 2 ) of the second optical component (112) to an adjusted target value (r 2 ) of the position (P 2 ) of the second optical component (112), which is set to an initial target value (r i ) of the position (P 2) of the second optical component (112) and the first actual value (y 1 ) of the position (P 1 ) of the first optical component (110). [2] Method according to claim 1, comprising controlling (S2) the position (P 1 ) of the first optical component (110) to a first target value (r 1 ) of the position (P 1 ) of the first optical component (110) based on the first actual value (y 1 ). [3] Method according to claim 2, wherein the controlling of the position (P 1 ) of the first optical component (110): Determining a first manipulated variable (u 1 ) based on a first deviation (e 1 ) of the first actual value (y 1 ) from the first setpoint (r 1 ), and Controlling a first actuator device (118) for positioning the first optical component (110) based on the first manipulated variable (u 1 ). [4] Method according to one of claims 1 to 3, wherein the control of the position (P 2 ) of the second optical component (112): Determining a second manipulated variable (u 2 ) based on a second deviation (e 2 ) of the second actual value (y 2 ) from the adjusted setpoint (r 2 ), and Controlling a second actuator device (120) for positioning the second optical component (112) based on the second manipulated variable (u 2 ). [5] Method according to one of claims 2 to 4, wherein the control of the position (P 1 ) of the first optical component (110) in a first pre-determined control frequency range (Δf R1 ), which is determined by a pre-determined interference frequency range (Δf s ) of the acoustic disturbance excitations of the first optical component (110). [6] Method according to claim 5, wherein the first pre-determined control frequency range (Δf R1 ) is a frequency range in which the first deviation (e 1 ) less than 10%, less than 5%, less than 3%, less than 1%, less than 0.1% and / or less than 0.01% of the first setpoint (r 1 ) is. [7] Method according to one of claims 2 to 6, wherein the regulation (S2) of the position (P 1 ) of the first optical component (110) in a pre-determined first control frequency range (Δf R1 ) takes place, the control (S3) of the position (P 2 ) of the second optical component (112) in a pre-determined second control frequency range (Δf R2 ) and the first and second control frequency range (Δf R1 , Δf R2 ) are different from each other. [8] Method according to one of claims 2 to 7, wherein the control (S2, S3) of the position (P 1) of the first optical component (110) and / or the second optical component (112) is carried out in each case by means of a control device (312, 314) which has at least one proportional control element (338), at least one integral control element (340) and at least one derivative control element (342), and / or the pre-determined first control frequency range (Δf R1 ) for controlling the position (P 1 ) of the first optical component (110) is preset by increasing the number of integral control elements (340') of the control device (312'). [9] Method according to one of claims 1 to 8, wherein the first and second optical components (110, 112) are arranged successively with respect to a beam path (S) of the lithography system (1), the first and second optical components (110, 112) are both arranged in an imaging beam path (S) of the lithography system (1), the first and second optical components (110, 112) are both components of a projection system (100) of the lithography system (1), and / or the first and second optical components (110, 112) are both configured to image a mask (7) on a substrate (13) arranged in an image plane (12) of the lithography system (1) and / or the projection system (100) of the lithography system (1). [10] Method according to one of claims 1 to 9, comprising regulating (S4) a pressure (D) of a liquid (204) in a liquid line (206) which is arranged for the liquid temperature control of the first optical component (110), wherein: an actual pressure value (y d ) of the pressure (D) of the liquid (204) is received, another control variable (u d ) based on a pressure deviation (e d ) of the actual pressure value (y d ) from a pressure setpoint (r d ) is determined, and a further actuator device (408) of a pressure change device (410) based on the determined further manipulated variable (u d ) to change the pressure (D) of the liquid (204) in the liquid line (206). [11] The method of claim 10, wherein the regulation (S2) of the position (P 1 ) of the first optical component (110) in a pre-determined first control frequency range (Δf R1 ) takes place, controlling (S4) the pressure (D) of the liquid (204) in the liquid line (206) in a pre-determined further control frequency range (Δf d ) and the first and the further control frequency range (Δf R1 , Δf d ) are different from each other. [12] Computing device (302) for compensating liquid-transmitted acoustic disturbances of a liquid-tempered optical component (110) of a lithography system (1), wherein the disturbances of the optical component (110) as a first optical component (110) are compensated by means of a non-liquid-tempered second optical component (112) of the lithography system (1), comprising: a receiving unit (306) for receiving a first and second actual value (y 1 , y 2 ) of a position (P 1 , P 2 ) corresponding to the first and second optical components (110, 112), and a control unit (310) for controlling the position (P 2 ) of the second optical component (112) to an adjusted target value (r 2 ) of the position (P 2 ) of the second optical component (112), which is set to an initial target value (r i ) of the position (P 2) of the second optical component (112) and the first actual value (y 1 ) of the position (P 1 ) of the first optical component (110). [13] Compensation system (300) for compensating liquid-transmitted acoustic disturbances of a liquid-tempered optical component (110) of a lithography system (1), wherein the disturbances of the optical component (110) as a first optical component (110) are compensated by means of a non-liquid-tempered second optical component (112) of the lithography system (1), comprising: the liquid-tempered first optical component (110), the non-liquid-tempered second optical component (112), an actuator device (120) for setting a position (P 2 ) of the second optical component (112), and a computing device (302) according to claim 12 for determining a manipulated variable (u 2) based on a deviation (e 2 ) of the second actual value (y 2 ) from the adjusted setpoint (r s ), and for controlling the actuator device (120) for positioning the second optical component (112) based on the second manipulated variable (u 2 ). [14] Lithography system (1), in particular EUV lithography system, with a computing device (302) according to claim 12 or a compensation system (300) according to claim 13. [15] Method for producing a control device (312, 312') for controlling a position (P 1 ) a liquid-tempered optical component (110) of a lithography system (1), comprising Determining (S1') an interference frequency range (Δf s ) from acoustic disturbances of the optical component (110), and Setting up (S2') a control component (316) of the control device (312, 312') such that the control of the position (P 1) of the optical component (110) in a pre-determined control frequency range (Δf R1 ), which is determined from the pre-determined interference frequency range (Δf s ) is different.

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