Operating method for a control device in a lithography apparatus

Abstract

Method (M200) for operating an actuator control device (103, 103a) of a lithography apparatus (100, 1, 25), wherein the lithography apparatus (100, 1, 25) has an optical element (101, M1–M6, 35, 36), at least one actuator (102), the at least one actuator control device (103, 103a, 103b) and an apparatus control device (104), wherein the actuator (102) is coupled to the optical element (101, M1–M6, 35, 36) for the purpose of acting on said optical element (101, M1–M6, 35, 36), wherein the actuator control device (103, 103a, 103b) is coupled to the at least one actuator (102) for the purpose of controlling an effect of the at least one actuator (102) and wherein the apparatus control device (104) is coupled to the actuator control device (103) for the purpose of controlling an optical property of the lithography apparatus (100, 1, 25), wherein the method (M200) includes: a) outputting (S216) a control signal to the at least one actuator (102) on the basis of a specification signal received from the apparatus control device (104); b) receiving (S222) a signal indicative of a deactivation of the apparatus control device (104) from the apparatus control device (104); and c) continuing to output (S224) the control signal to the at least one actuator (102).

Description

[0001] Carl Zeiss SMT GmbH

[0002] 1

[0003] OPERATING METHOD FOR A CONTROL DEVICE IN A LITHOGRAPHY APPARATUS

[0004] The present invention relates to a method for operating an actuator control de¬ vice in a lithography apparatus. Moreover, the present invention relates to a method for operating an apparatus control device in a lithography apparatus, and to a lithography apparatus.

[0005] The content of the priority application DE 102025 111228.2 is incorporated by reference in its entirety (incorporation by reference).

[0006] Microlithography is used to produce microstructured components, for example integrated circuits. The microlithography process is conducted with a lithography apparatus having an illumination system and a projection system. The image of a mask (reticle) illuminated by means of the illumination system is projected here by means of the projection system onto a substrate, for example a silicon wafer, which is coated with a light-sensitive layer (photoresist) and is arranged in the image plane of the projection system, in order to transfer the mask structure to the light-sensitive coating of the substrate.

[0007] In striving to achieve ever smaller structures in the production of integrated circuits, EUV lithography apparatuses that use light at a wavelength in the range of 0.1 nm to 30 nm, in particular 13.5 nm, are currently under development.

[0008] Since most materials absorb light at this wavelength, such EUV lithography apparatuses require the use of reflective optical units, i.e. mirrors, instead of refrac¬ tive optical units, i.e. lens elements, as used previously.

[0009] A lithography apparatus within the scope of the invention described here has at least one optical element, at least one actuator, at least one actuator control device and at least one apparatus control device. The at least one actuator is coupled to the optical element in a manner suitable and prepared for the effect of the actuator on the optical element. The actuator is preferably configured to deform the optical element and interconnected with said optical element, i.e. the "effect" preferably is a deformation of the optical element, preferably a bending of the optical element. The actuator control device is coupled to the at least one actuator in a manner suitable for controlling an effect of the at least one actuator on the optical element. The apparatus control device is coupled to the actuator control device in a manner suitable for controlling an optical property of the lithography apparatus. Deformation control is a technology for improving the imaging accuracy.Carl Zeiss SMT GmbH

[0010] 2

[0011] The subdivision into apparatus control device and actuator control device is a control device hierarchy. The actuator control device is a component control de¬ vice. All control devices are usually restarted when a control device such as the apparatus control device, the actuator control device and / or any other component control device is updated. For example, this is due to the fact that the component control devices are usually supplied with electrical energy by way of the apparatus control device.

[0012] It is currently common practice for a predetermined state of the actuator control device and of the at least one actuator to be adopted when the actuator control device restarts. For example, a voltage-controlled actuator is switched to a de-energized state (from most recently applied voltage to zero). This is a consequence of a step excitation of the optical element (from an output of the actuator corresponding to the most recently applied voltage to an output of the actuator corresponding to a voltage of zero). It may take a long time for a lithography apparatus having this technology for improving the imaging accuracy to attain a de¬ sired optical property. It may be the case that a step -like change in the control signal entails a reduction in the imaging quality lasting up to two weeks. This long period of time is at least accompanied by reduced productivity.

[0013] An electrostrictive actuator attached to the rear side of the mirror is an example of such an actuator. By preference, the effect of this actuator is developed parallel to the rear side of a mirror body (surface parallel actuation). Actuators of this type may be subject to various effects that may have a time dependence (drift), a dependence on antecedents (e.g. hysteresis) and / or a voltage dependence (creep). For example, a dependence on the antecedents and the voltage following a re-initialization (actuator zero volt event) may necessitate a run-in procedure over a period of two weeks in order to achieve a desired high imaging accuracy.

[0014] Against this background, a problem addressed by the present invention is that of providing a means for improving a productivity of a lithography apparatus.

[0015] Accordingly, a method for operating an actuator control device of a lithography apparatus is proposed. The lithography apparatus has an optical element, at least one actuator, the at least one actuator control device and an apparatus control device. The actuator is coupled to the optical element for the purpose of acting on said optical element. The actuator control device is coupled to the at least one actuator for the purpose of controlling an effect of said at least one actuator. The apparatus control device is coupled to the actuator control device for the purposeCarl Zeiss SMT GmbH

[0016] 3

[0017] of controlling an optical property of the lithography apparatus. The proposed method includes ■ A) outputting a control signal from the actuator control device to the at least one actuator on the basis of a specification signal received from the apparatus control device. B) receiving a signal indicative of a deactivation of the apparatus control device from the apparatus control device. C) continuing to output the control signal from the actuator control device to the at least one actuator.

[0018] By virtue of the actuator control device continuing to output the control signal, a state of the optical element and of the actuator is not modified even if the apparatus control device needs to be deactivated. Hence, a jump (large change of absolute value in a time-continuous or time-discrete profile) in the control signal or a discontinuity of the control signal, which would result in a long-term degradation of the optical element, is prevented. Thus, a productivity of the lithography apparatus is improved. It should be observed here that the productivity of the lithog¬ raphy apparatus is improved since, compared to previously, there now are fewer situations that lead to a long-term degradation of the optical element.

[0019] The effect of the actuator on the optical element is a deformation of the optical element by the at least one actuator in particular. In the meantime, a deformable optical element — or else a plurality of deformable optical elements — is used in order to improve an imaging accuracy. A technique for deforming optical elements is describedin DE102020201724A1. In that context, an electrostrictive element, as an actuator, is secured to a rear side of an optical element. For example, the optical element is deformed by a contraction or expansion of the electrostrictive element parallel to the rear side of the optical element (rear-side-parallel action). For example, the optical element is deformed towards a stiff frame behind the op¬ tical element by way of a build-up of force (rear-side-normal action). By preference, multiple actuators are arranged on the rear side of the optical element in a regular or irregular distribution. This can be thought of as a mat of multiple ac¬ tuators next to one another. A sensor for measuring a deformation of the optical element, as likewise describedin DE102020201724A1, is advantageous but not necessary in this invention.

[0020] In relation to the at least one actuator, the actuator control device and / or the apparatus control device can be configured as an open-loop controller or controller without feedback. For example, in relation to the at least one actuator, the actuator control device and / or the apparatus control device can be configured as a closed-loop controller or controller based on feedback. To gain knowledge about the deformation of the optical element, it is possible to resort to at least one of the following techniques: It may be the case that a mathematical model, whichCarl Zeiss SMT GmbH

[0021] 4

[0022] describes a deformation behaviour of the optical element mathematically, is provided in the actuator control device and / or in the apparatus control device. A deformation of the optical model can be determined using the mathematical model, for example on the basis of measured or stored and / or calculated parameters, state variables and / or profile data. It may be the case that at least one deformation sensor is coupled to the optical element and / or between the optical element and a reference element (inertial system) (for example, see DE102020201724A1 mentioned). It may be the case that imaging by the optical element is measured by way of the lithography apparatus, and the deformation of the optical element is inferred therefrom. It may be the case that a plurality of these methods are combined.

[0023] By preference, one actuator control device is assigned to all actuators of the optical element. The control signal is a signal which is or can be output to the actuator by the actuator control device and which preferably directly drives said actuator. It may be the case that the at least one actuator in each case is an electro-strictive element and / or piezoelectric element. In this case, the control signal is preferably a voltage signal and / or a charge signal. These control signals can be controlled particularly finely.

[0024] It may be the case that the method includes: E) receiving a signal indicative of a reactivation of the apparatus control device from the apparatus control device. In particular, this signal may be a notification signal indicating that the apparatus control device has been reactivated. By preference, this signal may be a signal indicating an initial phase of the reactivation such that the apparatus control device and the actuator control device (are able to) start a joint initialization.

[0025] It may be the case that the method includes: D) storing at least one parameter or parameter set indicative of a current state of the optical element, of a current state of the at least one actuator and / or of a current state of the actuator control device. F) transmitting the stored at least one parameter or parameter set to the apparatus control device, especially in response to the signal received in step E). In this way, the reactivated (e.g. restarted) apparatus control device is reliably informed about the current state such that the reactivation can be carried out without a jump.

[0026] It may be the case that the method includes: H) initializing, especially in response to the signal received in step E), a predefined fault handling function which is configured to transmit a signal and / or data to the apparatus control device in the event of a fault being detected by the actuator control device. To this end, the methodCarl Zeiss SMT GmbH

[0027] 5

[0028] may include: monitoring a profile of at least one changeable value (for example: specification signal, output voltage, output charge, temperature of the actuator, temperature of the optical element, absolute value of a deformation on the basis of a mathematical model, ...) for detecting a fault. Fault handling functions offer an option for reacting to a detected fault without a reset and hence without a jump in the control signal. To this end, this ensures a fault handling function in response to the reactivation signal.

[0029] It may be the case that a second actuator control device is connected in parallel with the dedicated actuator control device, and wherein the method includes ■ I) receiving a signal indicative of a pending software update for the actuator control devices, wherein the update requires or includes a restart of the respective updated actuator control device. J) ascertaining a sequence of the dedicated actuator control device and the other actuator control device for the pending update, wherein the sequence is preferably ascertained on the basis of which actuator control device is currently outputting the control signal in accordance with step A) or C). In other words: By preference, the actuator control device currently outputting the control signal continues to output while the other actuator control device performs the update. K) outputting the control signal in accordance with step A) or C) on the basis of the ascertainment in step J). L) performing the update on the basis of the ascertainment in step J). The second actuator control device is preferably structurally identical to the dedicated actuator control device. Providing two actuator control devices which perform the update in succession ensures that one actuator control device is available for outputting the control signal or at least for continuing to output the control signal. There is preferably a transfer of the output of the control signal from the actuator control device which has not yet been updated to the actuator control device which has already been updated successfully. Hence, this prevents a jump in the control signal even in those cases where a deactivation of the actuator control device cannot be avoided.

[0030] In this case, preferably in step K), the method preferably includes: transmitting at least one parameter or parameter set indicative of a current state of the optical element, of a current state of the at least one actuator and / or of a current state of the actuator control device, and / or the output control signal to the second actuator control device. This represents a preferred option for the seamless transfer of the control signal output.

[0031] It may be the case that the method includes: M) coordinating with the other actuator control device as to which actuator control device outputs the control signal in accordance with step A) or C). Step M) is preferably carried out at the start of theCarl Zeiss SMT GmbH

[0032] 6

[0033] runtime of the actuator control device and / or at regular intervals. For example, provision can be made for the same actuator control device to always remain in reserve or for the active actuator control device to change regularly. Coordination is preferably performed by exchanging signals between the actuator control de¬ vices. Coordination can also be specified by the provision of an appropriate parameter or parameters set and / or an instruction of the apparatus control device.

[0034] It may be the case that the method includes: N) receiving a signal indicative of a pending software update for the actuator control device, wherein the update does not include a restart. O) partially updating the actuator control device software, wherein the control signal continues to be output during the updating, in accord¬ ance with step C). This option provides an opportunity to perform "small" updates. For example, a parameter set can be overwritten, and / or a software of the actuator control device may be modularized (with at least one selectively deactivatable module). A jump in the control signal is prevented by virtue of the actuator control device not being deactivated or not being deactivated overall.

[0035] It may be the case that the method includes at least one control operating mode and one readiness operating mode. The control operating mode includes step A). Optionally, the control operating mode additionally includes at least one of steps B), D), I), J), K), M) and N). The readiness operating mode includes step C). Optionally, the readiness operating mode additionally includes at least one of steps E), F), G), I), J), K), M), N) and O). The method switches from the control operating mode into the readiness mode on the basis of step B). Thus, a state control with at least two states is proposed. This procedure was found to be able to be carried out particularly reliably and quickly.

[0036] It may be the case that the control operating mode includes the following: N) re¬ ceiving a signal indicative of a deactivation of the actuator control device from the apparatus control device. In this case, the method additionally includes a deactivation operating mode, and there is a switch from the control operating mode into the deactivation operating mode and / or from the readiness operating mode into the deactivation operating mode on the basis of step N). Thus, the proposed state control is extended to three states. This provides a particularly operationally reliable way for initiating and terminating a (rarely necessary) deactivation of the actuator control device.

[0037] The control operating mode (in technical terminology: on mode) can be referred to as a mode prepared for regular control of the at least one actuator and / or for adaptive control of the at least one actuator. The readiness mode (in technicalCarl Zeiss SMT GmbH

[0038] 7

[0039] terminology: always-on mode) can be referred to as a mode prepared for maintaining control of the at least one actuator. The deactivation mode can be referred to as a mode prepared for switching off and / or for updating and / or for restarting the actuator control device.

[0040] It may be the case that the method includes: requesting at least one parameter or parameters set from the apparatus control device, said parameter or parameter set being indicative of a most recently stored state of the optical element, of the at least one actuator, of the actuator control device, and / or being indicative of the specification signal. It may be the case that, in addition to that or in an alternative, the method includes: receiving a signal including at least one parameter or parameter set from the apparatus control device, wherein the parameter or parameter set is indicative of a most recently stored state of the optical element, of the at least one actuator, of the actuator control device, and / or is indicative of the specification signal. It may be the case that, after or during at least one of these two steps, the method includes: switching from the readiness operating mode into the control op¬ erating mode. Hence, resumption of the specification-value-based control may be preceded by an adjustment of the starting point (for the method) to the last known actual state, in order to prevent a jump in the control signal. These steps are particularly preferred following the partial update of the actuator control device in step O), as described above.

[0041] According to a next aspect of the invention, a method for operating an apparatus control device of a lithography apparatus is proposed. The lithography apparatus has an optical element, at least one actuator, at least one actuator control device and the apparatus control device. The actuator is coupled to the optical element for the purpose of acting on said optical element. The actuator control device is coupled to the at least one actuator for the purpose of controlling an effect of said at least one actuator. The apparatus control device is coupled to the actuator control device for the purpose of controlling an optical property of the lithography ap¬ paratus. The proposed method includes a prescriptive operating mode and a deactivation operating mode. The prescriptive operating mode includes: outputting a specification signal to the actuator control device. The deactivation operating mode includes: outputting a signal indicative of a deactivation of the apparatus control device to the actuator control device. This method serves as a possible counterpart on the part of the apparatus control device to the above-described method for operating an actuator control device. Thus, on the part of the apparatus control device, it provides means for preventing the deactivation of the actuator control device. Hence, a productivity of the lithography apparatus controlled overall by the apparatus control device is improved. What was described above in relation to theCarl Zeiss SMT GmbH

[0042] 8

[0043] method for operating an actuator control device applies mutatis mutandis. It can be said that the output signal does not relate to an energy supply to the actuator control device. It can be said that the output signal does not represent a termination of an energy supply to the actuator control device. It can be said that the output signal is purely information or a notification or message. It can be said that the output signal is not an absence and / or muting of a signal or of the specification signal.

[0044] It may be the case that the prescriptive operating mode includes: outputting a signal indicative of a reactivation of the apparatus control device to the actuator control device. Hence, the actuator control device, for example, can be reliably switched back from continuing to output the control signal, or keeping the latter constant, to outputting the control signal on the basis of the specification signal. Phrased more generally, this step may for example serve to keep the apparatus in a defined state or to transfer at least the apparatus into a defined state.

[0045] It may be the case that the prescriptive operating mode includes: receiving at least one parameter indicative of a current state of the optical element, of a current state of the at least one actuator and / or of a current state of the actuator control device from the actuator control device. These steps represent a start of the prescriptive operating mode following a reactivation. For example, by way of these steps it is possible to ensure that, in the event of a restart, the apparatus control device can infer the state of the actuator control device and / or of the at least one actuator and / or of the optical element, and hence an absolute-value jump in the specification signal to the actuator control device is prevented. The apparatus control device starts up smoothly as a result.

[0046] It may be the case that the prescriptive operating mode includes: initializing at least one predefined fault handling function which is configured to transmit a sig¬ nal and / or data from the actuator control device in the event of a fault being detected by the actuator control device while the method is being carried out. On the part of the apparatus control device, this step serves to set up the at least one fault handling function so that this provides a reliable option for transferring the actuator control device and the apparatus control device into a defined state, or keeping them in such a state, following the detection of a fault (e.g. incorrect instruction, incorrect value, technical fault and / or other fault).

[0047] According to yet another aspect of the invention, a computer program product is proposed, comprising instructions which, upon execution of the program by aCarl Zeiss SMT GmbH

[0048] 9

[0049] computer, cause the latter to carry out the above-described method for operating an actuator control device.

[0050] According to yet another aspect of the invention, a computer program product is proposed, comprising instructions which, upon execution of the program by a computer, cause the latter to carry out the above-described method for operating an apparatus control device.

[0051] A computer program product, such as e.g. a computer program means, can be pro¬ vided or supplied for example as a storage medium, such as e.g. a memory card, a USB stick, a CD-ROM, a DVD, or else in the form of a downloadable file from a server in a network. For example, in a wireless communications network, this can be effected by transferring an appropriate file comprising the computer program product or the computer program means.

[0052] According to yet another aspect of the invention, an actuator control device is proposed, the latter being configured to carry out the above-described method for op¬ erating an actuator control device. By preference, the actuator control device has a connector for a power supply device and is configured to use this to supply or apply energy to the at least one actuator and / or to control the latter. The actuator control device preferably has an interface which is suitable and configured for co¬ ordinating an update sequence with another actuator control device. The actuator control device has the features, properties and advantages of the above -described method for operating an actuator control device.

[0053] According to yet another aspect of the invention, an apparatus control device is proposed, the latter being configured to carry out the above-described method for operating an apparatus control device. The apparatus control device has the features, advantages and properties of the above-described method for operating an apparatus control device.

[0054] According to a next aspect of the invention, a lithography apparatus is proposed. The lithography apparatus has an optical element, at least one actuator, at least one actuator control device, an apparatus control device and at least one power supply device. The actuator is coupled to the optical element for the purpose of acting on said optical element. The actuator control device is coupled to the at least one actuator for the purpose of controlling an effect of said at least one actuator. The apparatus control device is coupled to the actuator control device for the purpose of controlling an optical property of the lithography apparatus. The power supply device is coupled to the apparatus control device for the purpose ofCarl Zeiss SMT GmbH

[0055] 10

[0056] supplying said apparatus control device with electrical energy. Moreover, the power supply device is coupled to the actuator control device for the purpose of supplying said actuator control device and the at least one actuator with electrical energy. The actuator control device is configured to carry out the above-described method for operating an actuator control device, and / or the apparatus control device is configured to carry out the above-described method for operating the apparatus control device. Hence, the features and advantages of the described method are shared by the actuator control device and hence also the lithography apparatus.

[0057] It may be the case that the lithography apparatus includes a further actuator control device which is connected in parallel with the first actuator control device. It may be the case that the further actuator control device is configured to carry out the above-described method for operating an actuator control device. Hence, the features and advantages of the described method are shared by the actuator control device and hence also the lithography apparatus.

[0058] For example, the lithography apparatus (sometimes also referred to as a projection exposure apparatus) may be an EUV lithography apparatus. EUV stands for "extreme ultraviolet" and refers to a wavelength of the operating light of between 0.1 nm and 30 nm. The lithography apparatus may also be a DUV lithography apparatus. DUV stands for "deep ultraviolet" and refers to a wavelength of the operating light of between 30 nm and 250 nm.

[0059] The invention can also be generalized to one aspect, according to which an apparatus is proposed, the latter including an apparatus control device, a component control device and a component to be controlled. In this respect, the term lithog¬ raphy apparatus can be replaced by the term apparatus, and the combination of optical element and actuator acting on the optical element can be replaced by the term component. Applications for "the apparatus" may for example include a safety -critic al system such as a heart-lung machine and / or any other medical-engineering or medical device, a power-plant controller and / or any other plant-construction system. Even within lithography, there are multiple applications such as a measuring device and / or a reticle repair device.

[0060] In this respect, the following is proposed according to yet another aspect: A method for operating a component control device in an apparatus, wherein the apparatus has a controllable component, the component control device and an apparatus control device, wherein the component control device is coupled to the component for the purpose of controlling said component and wherein theCarl Zeiss SMT GmbH

[0061] 11

[0062] apparatus control device is coupled to the component control device for the purpose of controlling a property of said apparatus related to the component. The proposed method includes: A) outputting a control signal from the component control device to the controllable component on the basis of a specification signal received from the apparatus control device. B) receiving a signal indicative of a deactivation of the apparatus control device from the apparatus control device. C) continuing to output the control signal from the component control device to the component. The properties, features and advantages of the above-described aspects apply accordingly. According to yet another aspect of the invention, a component control device is proposed, the latter being suitable and configured for carrying out the method for operating a component control device, as proposed above.

[0063] Moreover, the following is proposed accordingly: A method for operating an appa¬ ratus control device in an apparatus, wherein the apparatus has a controllable component, a component control device and the apparatus control device, wherein the component control device is coupled to the component for the purpose of controlling said component and wherein the apparatus control device is coupled to the component control device for the purpose of controlling a property of said apparatus related to the component. The proposed method includes a prescriptive operating mode and a deactivation operating mode. The prescriptive operating mode includes: outputting a specification signal to the component control device. The deactivation operating mode includes: outputting a signal indicative of a deactivation of the apparatus control device to the component control device. The properties, features and advantages of the above-described aspects apply accordingly. According to a further aspect, an apparatus control device is proposed, the latter being configured to carry out this proposed method for operating an ap¬ paratus control device.

[0064] In this respect, finally, an apparatus is also proposed, the latter having a controllable component, the component control device, an apparatus control device and a power supply device, wherein the component control device is coupled to the component for the purpose of controlling said component, wherein the apparatus control device is coupled to the component control device for the purpose of control¬ ling a property of said apparatus related to the component and wherein the power supply device is coupled to the apparatus control device for the purpose of supplying said apparatus control device with electrical energy and coupled to the component control device for the purpose of supplying said component control de¬ vice and the controllable component with electrical energy. The above- described features, properties and advantages apply accordingly.Carl Zeiss SMT GmbH

[0065] 12

[0066] “A” or “an” or “one” in the present case should not necessarily be understood as being restrictive to exactly one element. Instead, multiple elements, for example two, three or more, may also be provided. Any other numeral used here should also not be understood as a restriction to exactly the stated number of elements. Rather, unless indicated otherwise, numerical deviations upward and downward are possible.

[0067] Further possible implementations of the invention also comprise combinations, not explicitly mentioned, of features or embodiments described hereinabove or hereinafter with regard to the exemplary embodiments. A person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.

[0068] Further advantageous configurations and aspects of the invention are the subject of the dependent claims and of the exemplary embodiments of the invention that will be described hereinafter. The invention will be explained in more detail be¬ low on the basis of preferred embodiments with reference to the appended fig¬ ures.

[0069] Fig. 1 shows a schematic meridional section of an EUV lithography apparatus;

[0070] Fig. 2 shows a schematic section of a DUV lithography apparatus;

[0071] Fig. 3 shows a schematic control structure of a lithography apparatus according to an embodiment of the invention, which may preferably be an above- described EUV lithography apparatus or an above-described DUV lithography apparatus;

[0072] Fig. 4 shows a diagram of a proposed method for operating an actuator control device; and

[0073] Fig. 5 shows a diagram of a proposed method for operating an apparatus control device.

[0074] In the figures, identical or functionally identical elements have been provided with the same reference signs, unless indicated otherwise. It should also be noted that the illustrations in the figures are not necessarily true to scale.

[0075] Fig. 1 shows an embodiment of a projection exposure apparatus 1 (lithography apparatus), in particular an EUV lithography apparatus. An embodiment of anCarl Zeiss SMT GmbH

[0076] 13

[0077] illumination system 2 of the projection exposure apparatus 1 has, in addition to a light or radiation source 3, an illumination optics unit 4 for illuminating an object field 5 in an object plane 6. In an alternative embodiment, the light source 3 may also be provided as a module separate from the rest of the illumination system 2. In this case, the illumination system 2 does not comprise the light source 3.

[0078] A reticle 7 arranged in the object field 5 is exposed. The reticle 7 is held by a reti¬ cle holder 8. The reticle holder 8 is displaceable by way of a reticle displacement drive 9, in particular in a scanning direction.

[0079] Fig. 1 depicts, by way of elucidation, a Cartesian coordinate system with an x-di-rection x, a ydirection y and a z-direction z. The x-direction x runs perpendicularly into the plane of the drawing. The ydirection y runs horizontally, and the z-direction z runs vertically. The scanning direction runs along the ydirection y in Fig. 1. The z-direction z runs perpendicularly to the object plane 6.

[0080] The projection exposure apparatus 1 comprises a projection optics unit 10. The projection optics unit 10 serves for imaging the object field 5 into an image field 11 in an image plane 12. The image plane 12 extends parallel to the object plane 6. Alternatively, an angle between the object plane 6 and the image plane 12 that differs from 0° is also possible.

[0081] A structure on the reticle 7 is imaged onto a light-sensitive layer of a wafer 13 that is arranged in the region of the image field 11 in the image plane 12. The wafer 13 is held by a wafer holder 14. The wafer holder 14 is displaceable by way of a wafer displacement drive 15, in particular in the ydirection y. The displace¬ ment, firstly, of the reticle 7 by way of the reticle displacement drive 9 and, secondly, of the wafer 13 by way of the wafer displacement drive 15 may be implemented so as to be synchronized with one another.

[0082] The light source 3 is an EUV radiation source. The light source 3 emits in partic¬ ular EUV radiation 16, which is also referred to below as used radiation, illumination radiation or illumination light. The used radiation 16 has in particular a wavelength in the range between 5 nm and 30 nm. The light source 3 may be a plasma source, for example an LPP (laser produced plasma) source or a GDPP (gas discharge produced plasma) source. It may also be a synchrotron-based radiation source. The light source 3 may be a free electron laser (FEL).

[0083] The illumination radiation 16 emanating from the light source 3 is focused by a collector 17. The collector 17 may be a collector having one or more ellipsoidalCarl Zeiss SMT GmbH

[0084] 14

[0085] and / or hyperboloidal reflection surfaces. The illumination radiation 16 may be incident on the at least one reflection surface of the collector 17 with grazing inci¬ dence (Gl), i.e. at angles of incidence of greater than 45°, or with normal inci¬ dence (Nl), i.e. at angles of incidence of less than 45°. The collector 17 may be structured and / or coated, firstly to optimize its reflectivity for the used radiation and secondly to suppress extraneous light.

[0086] Downstream of 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 unit 4.

[0087] The illumination optics unit 4 comprises a deflection mirror 19 and, arranged downstream thereof in the beam path, a first facet mirror 20. The deflection mirror 19 may be a planar deflection mirror or alternatively a mirror with a beaminfluencing effect that goes beyond the pure deflection effect. In addition to that or in an alternative, the deflection mirror 19 may be embodied as a spectral filter that separates a used light wavelength of the illumination radiation 16 from extraneous light of a wavelength deviating therefrom. If the first facet mirror 20 is in a plane of the illumination optics unit 4 that is optically conjugate to the object plane 6 as a field plane, it is also referred to as a field facet mirror. The first facet mirror 20 comprises a multiplicity of individual first facets 21, which can also be referred to as field facets. Only some of these first facets 21 are illustrated in Fig. 1 by way of example.

[0088] The first facets 21 may take the form of macroscopic facets, in particular the form of rectangular facets or the form of facets with an arcuate or partly circular peripheral contour. The first facets 21 can be embodied as plane facets or alternatively as convexly or concavely curved facets.

[0089] As is known from DE 102008009600 Al, for example, the first facets 21 themselves may each also be composed of a multiplicity of individual mirrors, in particular a multiplicity of micromirrors. The first facet mirror 20 may in particular take the form of a microelectromechanical system (MEMS system). For details, reference is made to DE 102008009600 Al.

[0090] The illumination radiation 16 travels horizontally, i.e. in the ydirection y, be¬ tween the collector 17 and the deflection mirror 19.Carl Zeiss SMT GmbH

[0091] 15

[0092] In the beam path of the illumination optics unit 4, a second facet mirror 22 is arranged downstream of the first facet mirror 20. If the second facet mirror 22 is in a pupil plane of the illumination optics unit 4, it is also referred to as pupil facet mirror. The second facet mirror 22 may also be at a distance from a pupil plane of the illumination optics unit 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 Al, EP 1614008 Bl and US 6,573,978.

[0093] 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.

[0094] The second facets 23 may likewise be macroscopic facets, which can for example have a round, rectangular or else hexagonal boundary, or may alternatively be facets composed of micromirrors. In this regard, reference is likewise made to DE 10 2008009600 Al.

[0095] The second facets 23 may have plane reflection surfaces or, in an alternative to that, convexly or concavely curved reflection surfaces.

[0096] The illumination optics unit 4 is consequently a double-faceted system. This fundamental principle is also referred to as a fly's eye integrator.

[0097] It might be advantageous to arrange the second facet mirror 22 not exactly in a plane that is optically conjugate to a pupil plane of the projection optics unit 10. In particular, the second facet mirror 22 can be arranged so as to be tilted in rela¬ tion to a pupil plane of the projection optics unit 10, as described for example in DE 102017220586 Al.

[0098] The second facet mirror 22 is used to image the individual first facets 21 into the object field 5. The second facet mirror 22 is the last beam-shaping mirror or else actually the last mirror for the illumination radiation 16 in the beam path upstream of the object field 5.

[0099] In a further embodiment (not illustrated) of the illumination optics unit 4, a transfer optics unit contributing in particular to the imaging of the first facets 21 into the object field 5 may be arranged in the beam path between the second facet mirror 22 and the object field 5. The transfer optics unit may have exactly one mirror or else, alternatively, two or more mirrors arranged in succession in the beam path of the illumination optics unit 4. The transfer optics unit may inCarl Zeiss SMT GmbH

[0100] 16

[0101] particular comprise one or two normal-incidence mirrors (NI mirrors) and / or one or two grazing-incidence mirrors (GI mirrors).

[0102] In the embodiment shown in Fig. 1, the illumination optics unit 4 has exactly three mirrors downstream of the collector 17, specifically the deflection mirror 19, the first facet mirror 20 and the second facet mirror 22.

[0103] In a further embodiment of the illumination optics unit 4, the deflection mirror 19 can also be omitted, and so the illumination optics unit 4 may have exactly two mirrors downstream of the collector 17 in that case, specifically the first facet mirror 20 and the second facet mirror 22.

[0104] The imaging of the first facets 21 into the object plane 6 by means of the second facets 23 or using the second facets 23 and a transfer optics unit is generally only approximate imaging.

[0105] The projection optics unit 10 comprises a plurality of mirrors Mi numbered consecutively in accordance with their arrangement in the beam path of the projec¬ tion exposure apparatus 1.

[0106] In the example illustrated in Fig. 1, the projection optics unit 10 comprises six mirrors Ml to M6. Alternatives with four, eight, ten, twelve or any other number of mirrors Mi are likewise possible. The projection optics unit 10 is a doubly ob¬ scured optical unit. The penultimate mirror M5 and the last mirror M6 each have a passage opening for the illumination radiation 16. The projection optics unit 10 has an image-side numerical aperture that is greater than 0.5 and can also be greater than 0.6 and can be for example 0.7 or 0.75.

[0107] Reflection surfaces of the mirrors Mi may take the form of free-form surfaces without an axis of rotational symmetry. Alternatively, the reflection surfaces of the mirrors Mi may take the form of aspherical surfaces with exactly one axis of rotational symmetry of the reflection surface shape. Just like the mirrors of the illumination optics unit 4, the mirrors Mi may have highly reflective coatings for the illumination radiation 16. These coatings may be designed as multilayer coat¬ ings, in particular with alternating layers of molybdenum and silicon.

[0108] The projection optics unit 10 has a large object-image shift in the ydirection y between a ycoordinate of a centre of the object field 5 and a ycoordinate of the centre of the image field 11. This object-image offset in the ydirection y can be ofCarl Zeiss SMT GmbH

[0109] 17

[0110] approximately the same magnitude as a z-distance between the object plane 6 and the image plane 12.

[0111] The projection optics unit 10 may in particular have an anamorphic form. It has in particular different imaging scales Bx, By in the x- and ydirections x, y. The two imaging scales Bx, By of the projection optics unit 10 are preferably (Bx, By) = (+ / -0.25, + / -0.125). A positive imaging scale B means imaging without image inversion. A negative sign for the imaging scale B means imaging with image inversion.

[0112] The projection optics unit 10 consequently leads to a reduction in size with a ratio of 4'1 in the x-direction x, i.e. in a direction perpendicular to the scanning direc¬ tion.

[0113] The projection optics unit 10 leads to a reduction in size of 8H in the ydirection y, i.e. in the scanning direction.

[0114] Other imaging scales are likewise possible. Imaging scales with the same sign and the same absolute value in the x-direction x and ydirection y are also possible, for example with absolute values of 0.125 or of 0.25.

[0115] The number of intermediate image planes in the x-direction x and in the ydirec¬ tion y in the beam path between the object field 5 and the image field 11 can be the same or can differ, depending on the embodiment of the projection optics unit 10. Examples of projection optics units with different numbers of such intermedi¬ ate images in the x-direction x and the ydirection y are known from US 2018 / 0074303 Al.

[0116] In each case, one of the second facets 23 is assigned to exactly one of the first facets 21 in order to form a respective illumination channel for illuminating the ob¬ ject field 5. In particular, this may result in illumination according to the Kohler principle. The far field is decomposed into a multiplicity 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 respectively assigned to them.

[0117] The first facets 21 are each imaged onto the reticle 7 by an assigned second facet 23 with images overlaid over one another for the purpose of illuminating the ob¬ ject field 5. The illumination of the object field 5 is in particular as homogeneous as possible. It preferably has a uniformity error of less than 2%. Field uniformity can be achieved by overlaying different illumination channels.Carl Zeiss SMT GmbH

[0118] 18

[0119] An arrangement of the second facets 23 may geometrically define the illumina¬ tion of the entrance pupil of the projection optics unit 10. The intensity distribution in the entrance pupil of the projection optics unit 10 may be set by selecting the illumination channels, in particular the subset of the second facets 23 that guide light. This intensity distribution is also referred to as illumination setting or illumination pupil filling.

[0120] A likewise preferred pupil uniformity in the region of portions of an illumination pupil of the illumination optics unit 4 that are illuminated in a defined manner may be achieved by a redistribution of the illumination channels.

[0121] There follows a description of further aspects and details of the illumination of the object field 5 and in particular of the entrance pupil of the projection optics unit 10.

[0122] The projection optics unit 10 may have in particular a homocentric entrance pupil. The latter may be accessible. It may also be inaccessible.

[0123] The entrance pupil of the projection optics unit 10 regularly cannot be exactly il¬ luminated with the second facet mirror 22. In the case of imaging by the projec¬ tion optics unit 10 which telecentrically images the centre of the second facet mirror 22 onto the wafer 13, the aperture rays often do not intersect at a single point. However, it is possible to find an area in which the spacing of the aperture rays, which is determined in pairs, becomes minimal. This area is the entrance pupil or an area conjugate thereto in real space. In particular, this area exhibits a finite curvature.

[0124] It may be the case that the projection optics unit 10 has different poses of the entrance pupil for the tangential beam path and for the sagittal beam path. In this case, an imaging element, in particular an optical component of the transfer optics unit, should be provided between the second facet mirror 22 and the reticle 7. By means of this optical element, the different poses of the tangential entrance pupil and the sagittal entrance pupil may be taken into account.

[0125] In the arrangement of the components of the illumination optics unit 4 illus¬ trated in Fig. 1, the second facet mirror 22 is arranged in an area conjugate to the entrance pupil of the projection optics unit 10. The first facet mirror 20 is arranged so as to be tilted with respect to the object plane 6. The first facet mirror 20 is arranged so as to be tilted with respect to an arrangement plane defined byCarl Zeiss SMT GmbH

[0126] 19

[0127] the deflection mirror 19. The first facet mirror 20 is arranged so as to be tilted with respect to an arrangement plane defined by the second facet mirror 22.

[0128] Fig. 2 shows a schematic view of a DUV lithography apparatus 100, which comprises a beam-shaping and illumination system 26 and a projection system 27 (also referred to hereinafter as “projection lens”). In this case, DUV stands for “deep ultraviolet” and refers to a wavelength of the working light of between 30 nm and 250 nm. The beam shaping and illumination system 26 and the pro¬ jection system 27 are preferably each arranged in a vacuum housing (not shown). Each vacuum housing is evacuated with the aid of an evacuation device (not illustrated). The vacuum housings are surrounded by a machine room (not illus¬ trated), in which drive devices for mechanically moving or setting optical ele¬ ments can be provided. Furthermore, electrical controllers and the like can also be arranged in the machine room.

[0129] The DUV lithography apparatus 25 has a light source 28. For example, an ArF excimer laser that emits radiation 29 in the DUV range, at for example 193 nm, may be provided as the light source 28. The radiation 29 is focused in the beam shaping and illumination system 26. Furthermore, the desired operating wave¬ length (operating light) is extracted from the radiation 29 by filtering, for example. The beam shaping and illumination system 26 may also comprise optical elements which are not illustrated, for example mirrors or lens elements.

[0130] After passing through the beam shaping and illumination system 26, the radia¬ tion 29 is guided onto a photomask (reticle) 30. The photomask 30 is configured as a transmissive optical element and can be arranged outside the systems 26, 27. The photomask 30 has a structure which is imaged on a wafer 31 in reduced form by means of the projection system 27.

[0131] The projection system 27 has a plurality of lens elements 32, 33, 34 and / or mirrors 35, 36 for projecting an image of the photomask 30 onto the wafer 31. In this case, individual lens elements 32, 33, 34 and / or mirrors 35, 36 of the projection system 27 may be arranged symmetrically relative to an optical axis 37 of the projection system 27. It should be noted that the number of lens elements and mirrors shown here is purely by way of example and is not restricted to the number illustrated. A greater or lesser number of lens elements 32, 33, 34 and / or mirrors 35, 36 can also be provided.

[0132] An air gap between the last lens element (not shown) and the wafer 31 can be replaced by a liquid medium 38 which has a refractive index of >1. The liquidCarl Zeiss SMT GmbH

[0133] 20

[0134] medium 38 can be high -purity water, for example. Such a setup is also referred to as immersion lithography and has an increased photolithographic resolution. The medium 38 may also be referred to as an immersion liquid.

[0135] Fig. 3 schematically shows a control hierarchy of a lithography apparatus 100. The lithography apparatus 100 described in more detail below may be an EUV lithography apparatus 1 or a DUV lithography apparatus 25.

[0136] The lithography apparatus 100 has an optical element 101, at least one actuator 102, for example two actuator control devices 103a and 103b, an apparatus control device 104 and a power supply device 105. The actuator control devices 103a, b are referred to as actuator control device 103, which means both actuator control devices 103a, b without distinction.

[0137] For example, the optical element 101 can be one of the mirrors Ml to M6 in the EUV lithography apparatus 1 or one of the mirrors 35, 36 in the DUV lithogra¬ phy apparatus 25. Even though mirrors represent a preferred application of the invention, the invention is not restricted to mirrors.

[0138] The optical element 101 is a mirror which has a front side 106 and a rear side 107. Multiple actuators 102 are applied, in each case on an individual basis, to the rear side 107. The actuators 102 are electrostrictive actuators and are constructed and attached so as to lengthen or shorten parallel to the rear side 107 (surface parallel actuator). Lengthening or shortening of the actuators 102 exerts a bending moment on the optical element 101, and so said optical element 101 is deformed.

[0139] Each of the actuators 102 is electrically connected to both of the actuator control devices 103, in each case on an individual basis. Each actuator control device 103 is configured to apply a control signal to each actuator 102. The control signal is a (DC) voltage or an electric charge.

[0140] Each of the actuator control devices 103 is connected to the power supply device 105. Multiple power supply devices 105 could also be present, as many as a respective power supply device 105 for each control device 103, 104.

[0141] Each actuator control device 103 is connected to an apparatus control device 104. For example, the apparatus control device 104 transmits specification signals to the actuator control devices 103. By preference, the specification signal is aCarl Zeiss SMT GmbH

[0142] 21

[0143] target value. For example, the apparatus control device 104 transmits a target value for each actuator 102 to the actuator control device 103.

[0144] For example, the actuator control devices 103 transmit a signal indicative of at least one variable or invariable parameter and / or at least one profile of such a parameter to the apparatus control device 104.

[0145] Moreover, a fault handling function (for example realized as a so-called "callback") can be configured such that the apparatus control device 104 can transmit an error message to the actuator control device(s) 103, and / or the actuator control device(s) 103 can transmit an error message to the apparatus control device 104.

[0146] By preference, clocked connections which may have a guaranteed cycle time of e.g. 200 ps are preferably used for the specification signal and / or for the parameter signal. By preference, an unclocked connection is used to transmit an error message to a fault handling function or by means of a fault handling function.

[0147] The apparatus control device 104 is connected to the power supply device 105 in parallel with the actuator control devices 103. Hence, a power supply device of the actuator control devices 103 is independent of the apparatus control device 104.

[0148] A method 200 for operating an actuator control device 103 is described below. The method 200 is carried out on the first actuator control device 103a. Hence, the first actuator control device 103a may be referred to as a dedicated actuator control device 103a hereinafter, and the second actuator control device 103b may be referred to as another actuator control device 103b.

[0149] For example, the method M200 has three operating modes, specifically a control operating mode S201 (on mode or on) for a "normal" control operation, a readi¬ ness operating mode S202 (always-on mode, always-on / terminate mode, always on or always on / terminate) for an emergency control operation, and a deactivation operating mode S203 (terminate mode or terminate) for a non-control opera¬ tion. The operating modes may also be referred to as control states. It may be the case that the method is implemented as a temporal (changeable) sequence of steps. It may be the case that the method is implemented as an event-driven state method. Mixed forms can also be used.Carl Zeiss SMT GmbH

[0150] 22

[0151] In the method M200, there is no direct switch from the control operating mode S201 to the deactivation operating mode S203; instead, the method M200 switches between these two modes S201, S203 via the readiness operating mode S202. Hence there are four mode transitions S204-S207. An advantage of this variant lies in the fact that control mechanisms are implemented once and hence unique.

[0152] Steps carried out in the case of a mode transition S204 into the control operating mode S201 are described first.

[0153] In a step S210, the dedicated actuator control device 103a coordinates with the other actuator control device 103b to determine which actuator control device 103 outputs the control signal in accordance with step a) or c). By preference, one of the actuator control devices 103a, b is determined or selected as a standard actuator control device 103 in the process, and, conversely, the other one is determined or selected as reserve actuator control device 103.

[0154] In a step S211, a clocked connection (link) is initialized between the apparatus control device 104 and the actuator control device 103. For example, a cable connection is tested, and a transmission protocol is tested and / or agreed.

[0155] At least one stored parameter is transmitted from the actuator control device 103 to the apparatus control device 104 in a step S212. For example, this parameter may have been stored previously by the actuator control device 103 in a step S217 — described later. The parameter relates to a state of the actuator control device 103, a state of the actuator 102 and / or a state of the optical element 101. For example, the stored parameter may contain at least one static piece of information, for example a version number of the actuator control device, a serial number of the involved component(s) or the like.

[0156] A predefined fault handling function is initialized in a step S213. The fault handling function serves to transmit a signal and / or data from the dedicated actuator control device 103a to the apparatus control device 104. For example, the fault handling function may be triggered should a fault, for example a threshold being exceeded (safety limit value) or an impossible state (sensor fault), be detected by the actuator control device 103 during the execution of this method M200. For example, an error message is transmitted from the dedicated actuator control de¬ vice 103a to the apparatus control device 104.Carl Zeiss SMT GmbH

[0157] 23

[0158] At least one parameter or parameter set is requested by the dedicated actuator control device 103a from the apparatus control device 104 in a step S214. For example, this parameter is indicative of a most recently stored state of the optical element 101, of the at least one actuator 102, of the actuator control device 103a, b and / or is indicative of the most recently transmitted specification signal.

[0159] A signal from the apparatus control device 104 is received by the actuator control device 103 in a step S215. This signal is indicative of a parameter (set) described in S214. This step S215 preferably represents an alternative to step S214.

[0160] Next, the control operating mode S201 is described on the basis of the steps carried out in this mode.

[0161] A specification signal is received from the apparatus control device 104 in a step S216. For example, the specification signal is indicative of a target deformation of the optical element 101. In step S216, a control signal from the actuator control device 103a is output to the at least one actuator 102 on the basis of the specification signal received from the apparatus control device 104. For example, the spec¬ ification signal is a digital signal. For example, the control signal is a voltage value and / or an electric charge.

[0162] The at least one parameter indicative of the current state of the optical element 101, of the current state of the at least one actuator 102 and / or of the current state of the actuator control device 103 is stored in a step S217. Logical and / or physical states are preferably stored as parameters in this step.

[0163] A check as to whether the apparatus control device 104 is outputting a signal indicative of a deactivation of the apparatus control device 104 is carried out in a step S217. In that case, this signal is received by the actuator control device 103a, in step S217 in this case. This may also be an absence of a signal indicative of an active state of the apparatus control device 104.

[0164] A check as to whether a signal indicative of a pending software update for the actuator control devices 103a, 103b is received is carried out in a step S218, wherein the update necessitates a restart of the respective updated actuator control device 103a, b. For example, the signal may also consist in a provision of an updated software by means of the apparatus control device 104.

[0165] A check as to whether a signal indicative of a pending software update for the actuator control device 103a, b is received is carried out in a step S219, wherein theCarl Zeiss SMT GmbH

[0166] 24

[0167] update does not include a restart. For example, the signal may also consist in a provision of an updated software by means of the apparatus control device 104.

[0168] Steps S218, S219 can also be performed together. For example, there may be an initial check as to whether a signal indicative of a pending software update for the actuator control devices 103a, 103b is received. Then, a check can be carried out as to whether this is an update that necessitates a restart of the respective updated actuator control device 103a, b (unfriendly update) or does not include a restart (friendly update).

[0169] For the sake of simplicity, this description assumes that the apparatus control device 104 provides specifications for all other component control devices in each re¬ spect. For example, it is also possible that updates are managed, monitored and distributed by a central control device other than the apparatus control device. For example, a server monitoring a version control of at least some of the apparatus software is connected to the apparatus control device and the component control devices. An update may mean that software, including a portion of the software, is changed to a newer version or to an older version or to the same version with more or fewer functions. By preference, checking software versions and supplying new software is not implemented by way of the same connection as the specification of the specification signal and / or the transmission of current parameters.

[0170] A sequence relating to the order in which the dedicated actuator control device 103a and the other actuator control device 103b perform the pending update is ascertained in a step S220. The sequence is ascertained depending on which actuator control device 103a, b is currently outputting the control signal in accordance with step a) or c). For example, the sequence emerges from the coordination in step S210.

[0171] On the basis of step S220, a decision is made in a step S221 as to whether the dedicated actuator control device 103a outputs the control signal next, to be precise in accordance with step S216 in this control operating mode S201 or, in a step S224, in the readiness operating mode S202 (this will be described below). Step S221 thus initiates an output of the control signal.

[0172] By contrast, a check as to whether a signal indicative of a deactivation of the apparatus control device 104 is received by the actuator control device 103a from said apparatus control device 104 is carried out in a step S222. A specification signal is no longer received should the apparatus control device 104 no longer be active, andCarl Zeiss SMT GmbH

[0173] 25

[0174] so it is not possible to produce a control signal on the basis of said specification signal.

[0175] For example, each of steps S217 to S222 on their own can bring the actuator control device 103a to transition from the control operating mode S201 into the readiness operating mode S202.

[0176] A step carried out during the transition S205 into the readiness operating mode S202 is described next. In other implementations, it may also be the case that at least some of the steps S217 to S222 are part of the transition S205 from the control operating mode S201 into the readiness mode S202.

[0177] At least one limit value is specified for each of at least one monitored quantity in a step S223. For example, a limit value for a monitored quantity is specified. For example, one (upper limit or lower limit) or more limit values (upper limit and lower limit) are specified for each of multiple monitored quantities. Observing the limit values should be monitored for each of the monitored quantities during the readiness operating mode. For example, this comprises^ monitoring at least one voltage and / or any other electrical quantity, monitoring at least one temperature of the actuator and / or of the optical element, and / or monitoring a cable connection to the at least one actuator.

[0178] Steps carried out during the readiness operating mode S202 are described next.

[0179] The control signal continues to be output to the at least one actuator 102 by the actuator control device 103a in a step S224. It can also be said that the control signal is kept constant.

[0180] Optionally, the software of the actuator control device 103a is partially updated in a step S225, wherein the control signal continues to be output in accordance with step S224 during the update. For example, a partial update can be understood to mean that a module is updated or that a parameter set is overwritten or that a link refers to a new file rather than to an old file.

[0181] On the basis of the limit values defined in S223, monitoring whether the at least one monitored quantity observes the at least one respective limit value is performed in a step S226. The method remains in the readiness mode S202 if all limit values are observed. A limit value not being observed means that the actuator control device 103a with the limited means of continuing to output the control signalCarl Zeiss SMT GmbH

[0182] 26

[0183] cannot operate the apparatus stably. As a consequence, the embodiment of the method switches to the deactivation mode S203, preferably by the transition S206.

[0184] A check as to whether a signal indicative of a reactivation of the apparatus control device 104 is received by the actuator control device 103 from said apparatus control device 104 is carried out in a step S227. The embodiment of the method M200 switches into the control mode S201, preferably by the transition S204, if such a signal is received.

[0185] A check as to whether a signal indicative of a deactivation of the actuator control device 103 is received is carried out in a step S228. This signal can be used to switch off the actuator control device 103, or an output of the control signal can be terminated.

[0186] An exemplary step which for example can be carried out during the transition S206 into the deactivation operating mode S103 is described next.

[0187] Still active interfaces of the actuator control device 103a are terminated in a step S229. For example, a fault handling function may still be active, and the actuator control device 103a now unregisters therefrom.

[0188] Exemplary steps carried out during the deactivation operating mode S203 are de¬ scribed next.

[0189] An energy supply from the power supply device 205 to the actuators 102 via the actuator control device 103 is interrupted in a step S230. The actuators 102 and the optical element 101 relax as a consequence.

[0190] The update is performed in step S231 on the basis of the ascertainment in step S220. By way of example, the actuator control device 203a has waited in the control step S201 or the readiness step S202.

[0191] The actuator control device 103 is restarted in a step S232.

[0192] Finally, a transition S207 is provided from the deactivation operating mode S203 into the readiness operating mode S202. For example, the latter contains step S223 already described, wherein the limit values are defined for monitored quantities. Moreover, provision can be made for the transition S207 to be the start of an operation of the actuator control device 203.Carl Zeiss SMT GmbH

[0193] 27

[0194] In an alternative — not illustrated — there is a method in which there is a direct switch between two respective operating modes such that there are three operating modes and six mode transitions. An advantage of this variant can be seen in the fact that no checks required only for the readiness operating mode need to be performed during a switch between the control operating mode and the deactiva¬ tion operating mode.

[0195] Next, a method M300 for operating the apparatus control device 104 is described with the aid of the diagram in Fig. 5. The method has a prescriptive operating mode S301 and a deactivation operating mode S302, and a transition S303 into the prescriptive operating mode S301 and a transition S304 into the deactivation operating mode S302.

[0196] The transition S303 into the prescriptive operating mode S301 is described first:

[0197] A signal indicative of an (upcoming) switch into the prescriptive operating mode S301 of the apparatus control device 104 is output to the actuator control devices 103a and 103b in a step S310. This switch may correspond to an activation of the apparatus control device 104 and a reactivation of the apparatus control device 104. In this context, the apparatus control device 104 being active is for example understood to mean an operation in the prescriptive operating mode S301. The activation or active state of the apparatus control device 104 may be understood as the opposite of a deactivation or inactive state of the apparatus control device 104.

[0198] More generally: the terms "active" and "deactivate" or "inactive" do not relate to doing anything but to controlling. The apparatus control device 104 controls and is active when it generates and outputs the specification value. The actuator control device 103a, 103b controls and is active when it generates and outputs the control signal.

[0199] At least one parameter is received from the actuator control device 103 in a step S311. The parameter is indicative of a current state of the optical element 101, of a current state of the at least one actuator 102 and / or of a current state of the actuator control device 103. This at least one parameter may be a parameter set.

[0200] The predefined fault handling function is initialized in a step S312. Step S312 is the counterpart on the part of the apparatus control device 104 to step S213 on the part of the actuator control device 103. The fault handling function serves to transmit a signal and / or data from the actuator control device 103 to theCarl Zeiss SMT GmbH

[0201] 28

[0202] apparatus control device 104 in the case of a fault detected by the actuator control device 103 while the method is carried out.

[0203] At least one parameter is transmitted to the actuator control device 103 in a step S313. For example, step S313 is transmitted in response to the request in S214 or without a request for a reception in S215.

[0204] The at least one parameter in S311, S217 and / or S212 relates to a current state of the optical element 101, of the at least one actuator 102 and / or of the at least one actuator control device 103. For example, this may include a parameter which is permanently stored in the actuator control device 103, for instance a se¬ rial number or a constant specified by software and / or a control model. For example, this may also include a parameter known to the actuator control device 103 from the prior operating history, for example a previously specified value of a specification signal and / or a previously output value of the control signal and / or a value calculated from the operating history such as a value of a deformation of the optical element 101 on the basis of a model stored in the actuator control device and at least one previously output control signal. For example, this may also include a parameter read by the actuator control device 103 by way of a sensor, for example a value of a deformation of the optical element, or a temperature of the optical element and / or of the at least one actuator.

[0205] In contrast thereto, the at least one parameter or parameter set in S313, S214 and / or S215 relates to the apparatus overall. For example, this may include a parameter which is permanently stored in the apparatus control device 104, for instance a serial number or a constant specified by software and / or a control model. For example, this may also include a parameter known to the apparatus control device 104 from the prior operating history, for example a previously specified value of a specification signal and / or a value calculated from the operating history such as a value of a deformation of the optical element 101 on the basis of a model stored in the apparatus control device 104 and at least one previously output specification signal. For example, this may also include a parameter read by the apparatus control device 104 by way of a sensor, for example a value of a deformation of the optical element, a temperature of the optical element and / or a position and size of an imaging aberration.

[0206] Steps S311, S217 and / or S212 on the one hand and S313, S214 and / or S215 on the other hand complement each other and are preferably complementary to one another such that they yield a common status image of the lithography apparatus 100 (which is as complete as possible).Carl Zeiss SMT GmbH

[0207] 29

[0208] The prescriptive operating mode S301 is described next. For example, the latter includes a step S314, wherein a specification signal is output to the actuator control device 103. For example, the specification signal is generated on the basis of a direct deformation measurement (e.g. by measuring a position and pose of the optical element 101) and / or an indirect deformation measurement (e.g. by meas¬ uring an image representation generated by the optical element 101).

[0209] The transition S304 into the deactivation operating mode S302 is described next.

[0210] A signal is transmitted to the actuator control device(s) 103 in a step S315, for example by the apparatus control device 104. This signal is indicative of the need to update the respective actuator control device 103, and this update requires a restart of the respective actuator control device 103.

[0211] A signal is transmitted to the actuator control device(s) 103 in a step S316, for example by the apparatus control device 104. This signal is indicative of the need to update, and this update does not require a restart of the respective actuator control device 103.

[0212] A signal indicative of a deactivation of the apparatus control device 104 is output to the actuator control device 103 in a step S317. In particular, the step S313 does not include interrupting an energy supply to the actuator control device 103 and / or to the at least one actuator 102. It can be said that this is a purely informative or instructive step.

[0213] For example, the deactivation operating mode S302 contains the following two steps:

[0214] The apparatus control device 104 is updated in a step S318. A consequence of this update is that no specification signal is generated and output to the actuator control device 103, at least during the time of updating.

[0215] The apparatus control device 104 is restarted in a next step S319.

[0216] A jump or a pause in the profile of the control signal to the at least one actuator 102 is prevented because the actuator control device 103 has the step S224 of continuing to output and / or because the apparatus control device 104 does not interrupt an energy supply to the actuator control device 103. Therefore, the lithog¬ raphy apparatus 100 can be operated with high productivity.Carl Zeiss SMT GmbH

[0217] 30

[0218] Although the present invention has been described on the basis of exemplary embodiments, it is modifiable in diverse ways.Carl Zeiss SMT GmbH

[0219] 31

[0220] LIST OF REFERENCE SIGNS

[0221] 1 EUV lithography apparatus

[0222] 2 Illumination system

[0223] 3 Light source

[0224] 4 Illumination optics unit

[0225] 5 Object field

[0226] 6 Object plane

[0227] 7 Reticle

[0228] 8 Reticle holder

[0229] 9 Reticle displacement drive

[0230] 10 Projection optics unit

[0231] 11 Image field

[0232] 12 Image plane

[0233] 13 Wafer

[0234] 14 Wafer holder

[0235] 15 Wafer displacement drive

[0236] 16 Illumination radiation

[0237] 17 Collector

[0238] 18 Intermediate focal plane

[0239] 19 Deflection mirror

[0240] 20 First facet mirror

[0241] 21 First facet

[0242] 22 Second facet mirror

[0243] 23 Second facet

[0244] 25 DUV lithography apparatus

[0245] 26 Beam shaping and illumination system 27 Projection system

[0246] 28 Light source

[0247] 29 Radiation

[0248] 30 Photomask or reticle

[0249] 31 Wafer

[0250] 32 Lens element

[0251] 33 Lens element

[0252] 34 Lens element

[0253] 35 Mirror

[0254] 36 Mirror

[0255] 37 Optical axis

[0256] 38 Liquid medium

[0257] 100 Lithography apparatusCarl Zeiss SMT GmbH

[0258] 101 Optical element

[0259] 102 Actuator

[0260] 103 Actuator control device

[0261] 103a First actuator control device / dedicated actuator control device 103b Second actuator control device / other actuator control device 104 Apparatus control device

[0262] 105 Power supply device

[0263] 106 Front side

[0264] 107 Rear side

[0265] Ml Mirror

[0266] M2 Mirror

[0267] M3 Mirror

[0268] M4 Mirror

[0269] M5 Mirror

[0270] M6 Mirror

[0271] M200 Method for operating an actuator control device

[0272] 5201 Control operating mode

[0273] 5202 Readiness operating mode

[0274] 5203 Deactivation operating mode

[0275] 5204 Transition

[0276] 5205 Transition

[0277] 5206 Transition

[0278] 5207 Transition

[0279] 5210 Coordinating multiple actuator control devices

[0280] 5211 Initializing a clocked connection

[0281] 5212 Transmitting a stored parameter

[0282] 5213 Initializing a fault handing function

[0283] 5214 Requesting a parameter from the apparatus control device 5215 Receiving a parameter from the apparatus control device 5216 Outputting a control signal to the actuator

[0284] 5217 Storing at least one parameter

[0285] 5218 Receiving a signal to perform an update and a restart 5219 Receiving a signal to perform an update without a restart 5220 Ascertaining an update sequence of the actuator control devices 5221 Making a decision about outputting the control signal 5222 Receiving a signal indicative of a deactivation of the apparatus control device

[0286] 5223 Specifying a limit value for a monitored quantity

[0287] 5224 Continuing to output the control signal

[0288] 5225 Partially updating the actuator control deviceCarl Zeiss SMT GmbH

[0289] 33

[0290] 5226 Monitoring the monitored quantity or quantities

[0291] 5227 Receiving a signal indicative of a reactivation of the apparatus control device

[0292] 5228 Receiving a signal indicative of a deactivation of the actuator control device

[0293] 5229 Terminating active interfaces

[0294] 5230 Interrupting an energy supply to the actuator

[0295] 5231 Performing the update

[0296] 5232 Restarting

[0297] M300 Method for operating an apparatus control device

[0298] 5301 Prescriptive operating mode

[0299] 5302 Deactivation operating mode

[0300] 5303 Transition

[0301] 5304 Transition

[0302] 5310 Outputting a signal indicative of a reactivation of the apparatus control device

[0303] 5311 Receiving at least one parameter

[0304] 5312 Initializing a fault handing function

[0305] 5313 Transmitting a parameter to the actuator control device

[0306] 5314 Outputting a specification signal

[0307] 5315 Transmitting a signal indicative of an update that requires a restart of the actuator control device

[0308] 5316 Transmitting a signal indicative of an update that does not require a restart of the actuator control device

[0309] 5317 Outputting a signal indicative of a deactivation of the apparatus control device

[0310] 5318 Updating the apparatus control device

[0311] 5319 Restarting the apparatus control device

Claims

Carl Zeiss SMT GmbH34CLAIMS1. Method (M200) for operating an actuator control device (103, 103a) of a lithography apparatus (100, 1, 25), wherein the lithography apparatus (100, 1, 25) has an optical element (101, M1-M6, 35, 36), at least one actuator (102), the at least one actuator control device (103, 103a, 103b) and an apparatus control device (104), wherein the actuator (102) is coupled to the optical element (101, M1-M6, 35, 36) for the purpose of acting on said optical element (101, M1-M6, 35, 36), wherein the actuator control device (103, 103a, 103b) is coupled to the at least one actuator (102) for the purpose of controlling an effect of the at least one actuator (102) and wherein the apparatus control device (104) is coupled to the actuator control device (103) for the purpose of controlling an optical property of the lithog¬ raphy apparatus (100, 1, 25),wherein the method (M200) includes:a) outputting (S216) a control signal to the at least one actuator (102) on the basis of a specification signal received from the apparatus control device (104);b) receiving (S222) a signal indicative of a deactivation of the apparatus control device (104) from the apparatus control device (104); andc) continuing to output (S224) the control signal to the at least one actuator (102).

2. Method according to Claim 1, wherein the at least one actuator (102) in each case is an electrostrictive element and / or piezoelectric element; and wherein the control signal is a voltage signal and / or a charge signal.

3. Method according to Claim 1 or 2, wherein the method (M200) includes: d) storing (S217) at least one parameter indicative of a current state of the optical element (101, M1-M6, 35, 36), of a current state of the at least one actuator (102) and / or of a current state of the actuator control device (103, 103a);e) receiving (S227) a signal indicative of a reactivation of the apparatus control device (104) from the apparatus control device (104); andf) transmitting (S212) the stored at least one parameter to the apparatus control device (104).

4. Method according to any of Claims 1-3, wherein the method (M200) includes:e) receiving (S227) the signal or a signal indicative of the reactivation or a reactivation of the apparatus control device (104) from the apparatus control device (104); andCarl Zeiss SMT GmbH35h) initializing (S213) a predefined fault handling function which is configured to transmit a signal and / or data to the apparatus control device (104) in the event of a fault being detected by the actuator control device (103).

5. Method according to any of Claims 1-4, wherein a second actuator control device (103b) is connected in parallel with the dedicated actuator control device (103a) and wherein the method includes:i) receiving (S218) a signal indicative of a pending software update for the actuator control devices (103, 103a, 103b), wherein the update requires a restart of the respective updated actuator control device (103 103a, 103b);j) ascertaining (S220) a sequence of the dedicated actuator control device (103a) and the other actuator control device (103b) for the pending update, wherein the sequence is preferably ascertained on the basis of which actuator control device (103, 103a, 103b) is currently outputting the control signal in accord¬ ance with step a) or c) (S216 or S224);k) outputting (S216, S224) the control signal in accordance with step a) or c) on the basis of the ascertainment (S220) in step j); andl) performing (S231, S232) the update on the basis of the ascertainment (S220) in step j).

6. Method according to Claim 5, wherein the method (M200) includes:m) coordinating (S210) with the other actuator control device (103b) as to which actuator control device (103a, 103b) outputs the control signal in accordance with step a) or c) (S216 or S224).

7. Method according to any of Claims 1-6, wherein the method (M200) includes:n) receiving (S219) a signal indicative of a pending software update for the actuator control device (103a), wherein the update does not include a restart;o) partially updating (S225) the actuator control device software, wherein the control signal continues to be output during the updating (S225), in accordance with step c) (S224).

8. Method according to any of Claims 1-7, wherein the method (M200) includes at least a control operating mode (S201) and a readiness operating mode (S202);wherein the control operating mode (S201) includes step a) (S216); wherein the readiness operating mode (S202) includes step c) (S224); and wherein the method (M200) switches from the control operating mode (S201) into the readiness mode (S202) on the basis of step b) (S222).Carl Zeiss SMT GmbH369. Method according to Claim 8, wherein the method (M200) includes:n) receiving (S228) a signal indicative of a deactivation of the actuator control device (103) from the apparatus control device (104); andwherein the method (M200) additionally includes a deactivation operating mode (S2023) and switches from the control operating mode (S201) into the deactivation operating mode (S203) and / or from the readiness operating mode (S202) into the deactivation operating mode (S203) on the basis of step n) (S228).

10. Method (M300) for operating an apparatus control device (104) of a lithography apparatus (100, 1, 25), wherein the lithography apparatus (100, 1, 25) has an optical element (101, M1-M6, 35, 36), at least one actuator (102), at least one actuator control device (103, 103a, 103b) and the apparatus control device (104), wherein the actuator (102) is coupled to the optical element (101, M1-M6, 35, 36) for the purpose of acting on said optical element (101, M1-M6, 35, 36), wherein the actuator control device (103) is coupled to the at least one actuator (102) for the purpose of controlling an effect of the at least one actuator (102) and wherein the apparatus control device (104) is coupled to the actuator control device (103) for the purpose of controlling an optical property of the lithography apparatus (100, 1, 25),wherein the method (M300) includes a prescriptive operating mode (S301) and a deactivation operating mode (S302),wherein the prescriptive operating mode (S301) includes:outputting (S314) a specification signal to the actuator control device; andwherein the deactivation operating mode (S302) includes:outputting (S317) a signal indicative of a deactivation of the apparatus control device (104) to the actuator control device (103, 103a, 103b).

11. Method according to Claim 10, wherein the method (M300) includes:outputting (S310) a signal indicative of a reactivation of the apparatus control device (104) to the actuator control device (103, 103a, 103b); and receiving (S311) at least one parameter indicative of a current state of the optical element (101, M1-M6, 35, 36), for a current state of the at least one actuator (102) and / or for a current state of the actuator control device (103, 103a, 103b) from the actuator control device (103).

12. Method according to Claim 10 or 11, wherein the method (M300) includes:outputting (S310) the signal or a signal indicative of a reactivation of the apparatus control device (104) to the actuator control device (103, 103a, 103b); andCarl Zeiss SMT GmbH37initializing (S312) a predefined fault handling function which is configured to transmit a signal and / or data from the actuator control device (103, 103a, 103b) in the event of a fault being detected by the actuator control device (103, 103a, 103b).

13. Lithography apparatus (100, 1, 25), having an optical element (101, M1-M6, 35, 36), at least one actuator (102), an actuator control device (103, 103a, 103b), an apparatus control device (104) and at least one power supply device (105), wherein the actuator (102) is coupled to the optical element (101, M1-M6, 35, 36) for the purpose of acting on said optical element (101, M1-M6, 35, 36), wherein the actuator control device (103, 103a, 103b) is coupled to the at least one actuator (102) for the purpose of controlling an effect of the at least one actuator (102), wherein the apparatus control device (104) is coupled to the actuator control device (103, 103a, 103b) for the purpose of controlling an optical property of the lithography apparatus (100, 1, 25) and wherein the power supply device (105) is coupled to the apparatus control device (104) for the purpose of supplying the apparatus control device (104) with electrical energy and coupled to the actuator control device (103, 103a, 103b) for the purpose of supplying the actuator control device (103, 103a, 103b) and the at least one actuator (102) with electrical energy, wherein the actuator control device (103, 103a, 103b) is configured to carry out the method (M200) according to any of Claims 1 to 9 and / or the apparatus control device (104) is configured to carry out the method (M300) according to any of Claims 10 to 12.

14. Lithography apparatus according to Claim 13, including a further actuator control device (103b) connected in parallel with the first actuator control device (103a).

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