TW202401130A - Supporting components of an optical device - Google Patents

Abstract

The present invention relates to an optical arrangement of a microlithographic imaging device, particularly for using light in the extreme UV (EUV) range, comprising a group of optical elements, a support structure (104.2), an active support device (108) and a control device (106). The group of optical elements comprises a plurality N of optical elements (M1 to M6) which are supported on the support structure (104.2) by way of the active support device (108). The active support device (108) comprises an active support unit (108.1, 108.2) for each optical element (M1 to M6) of the group of optical elements, which active support unit is configured to adjustably support the optical element (M1 to M6) on the support structure (104.2) under control device (106) control. The group of optical elements comprises a first subgroup with a plurality M of first optical elements (M2, M4, M5, M6) and a second subgroup with a number K of second optical elements (M1, M3). The control device (106) and a first active support unit (108.1) assigned to the respective first optical element (M2, M4, M5, M6) are configured to adjust the first optical element (M2, M4, M5, M6) in at least one degree of freedom with a maximum control bandwidth which is within a first control bandwidth range. Further, the control device (106) and a second active support unit (108.2) assigned to the respective second optical element (M1, M3) are configured to adjust and/or deform the second optical element (M1, M3) in at least one degree of freedom with a maximum control bandwidth which is within a second control bandwidth range. In this case, the first control bandwidth range is below the second control bandwidth range and spaced apart from the second control bandwidth range by an interval. The interval is at least 50%, preferably at least 100%, further preferably at least 125% of an upper limit of the first control bandwidth range and/or at least 40 Hz to 80 Hz, preferably 50 Hz to 175 Hz, further preferably 75 Hz to 125 Hz.

Description

Optical device support components

The present invention relates to an optical arrangement of a lithographic imaging device adapted to utilize ultraviolet light, in particular light in the extreme ultraviolet (EUV) range. The invention also relates to an optical imaging device having the optical configuration, a method for supporting an optical element, and an optical imaging method. The present invention can be used in conjunction with any desired optical imaging method. The invention is particularly advantageous for use in the production or inspection of microelectronic circuits and optical components used there (eg photomasks). [Cross-reference to related applications]

This application claims priority under Section 119 of 35 U.S.C. to German Patent Application No. 10 2022 204 044.9 filed on April 27, 2022, the entire content of which is incorporated herein by reference.

Optical devices used in connection with the production of microelectronic circuits typically contain a plurality of optical element units containing one or more optical elements, such as lens elements, mirrors or gratings arranged in the imaging optical path. The optical elements typically cooperate in the imaging process to transfer an image of an object (eg, a pattern formed on a reticle) to a substrate (eg, a so-called wafer). Optical elements are typically combined into one or more functional groups that are selectively maintained in separate imaging units. Especially in the case where the operating wavelength of the main refractive system is in the so-called vacuum ultraviolet range (VUV, for example, a wavelength of 193 nm), this imaging unit is usually formed by an optical module carrying one or more optical elements. The optical module typically includes a support structure with a substantially annular external support unit that supports one or more optical component holders, which in turn retains the optical components.

The continued progress in the miniaturization of semiconductor devices has led to a continued increase in the need to improve the resolution of optical systems used to produce semiconductor devices. This demand for increased resolution will inevitably require increased numerical aperture (NA) and imaging accuracy of the optical system.

One way to increase optical resolution is to reduce the wavelength of light used in the imaging process. The trend in system development in recent years has been increasingly towards the use of light in the so-called extreme ultraviolet (EUV) range, typically with wavelengths from 5 nm to 20 nm, and in most cases around 13 nm. In this EUV range it is no longer possible to use conventional refractive optics. This is because the absorbance of the materials used in refractive optical systems is too high in this EUV range to achieve acceptable imaging results at the available optical power. Therefore, it is necessary to use reflective optical systems for imaging in this EUV range.

In this EUV range, this shift to purely reflective optical systems with high numerical apertures (e.g., NA > 0.4, or even NA > 0.5) results in considerable challenges in the design of imaging devices.

The above factors result in very strict requirements on the position and/or orientation of the optical elements involved in imaging relative to each other, as well as on the deformation of each optical element, in order to achieve the desired imaging accuracy. Furthermore, it is necessary to maintain this high imaging accuracy during the entire operation and ultimately throughout the entire life cycle of the system.

Thus, in a well-defined manner, the components of an optical imaging device that support cooperation during imaging (i.e., for example, the optics of the illumination device, the reticle, the optics of the projection device, and the substrate) are intended to maintain between these components Predetermined, well-defined spatial relationships and minimizing undesirable deformations that these components may produce, ultimately achieving high-probability imaging quality.

This problem is particularly likely to accompany high numerical apertures, which require the use of optical elements with relatively large dimensions and associated with large masses or moments of inertia. Due to these large masses or moments of inertia, it is difficult to ensure for commercial purposes the high dynamics required, during the highly accurate positioning of the components relevant for optical imaging (in particular the optical elements of the projection device) relative to each other, in order to ultimately obtain The smallest possible aberration or the highest possible imaging quality.

In order to face the problem of greater hysteresis caused by larger components, patent case WO 2013/004403 A1 (Kwan et al., the entire disclosure of which is incorporated herein by reference) has proposed to use the heaviest optical element as an inertial Reference and eventual alignment of other optics to this particularly slow optic. Although the optical elements forming this inertial reference are actively supported, they are only supported over a relatively small maximum control bandwidth, while all remaining components must be aligned to this inertial reference which has a significantly higher maximum control bandwidth. . One issue here, however, is the outlay cost required to meet the requirements, in terms of control dynamics, and the numerical aperture of these remaining optical elements will also increase, causing these optical elements to also become larger and larger .

It is therefore an object of the present invention to specify an optical configuration of a lithographic imaging device which is suitable for the use of ultraviolet light used, in particular light in the extreme ultraviolet (EUV) range. The present invention is also related to providing an optical imaging device having such an optical configuration, a method of supporting an optical element and an optical imaging method, which do not have the above-mentioned disadvantages, or have disadvantages to a lesser extent, and in a simple manner, especially while at least maintaining imaging While the quality remains unchanged, the actual cost of the imaging device is reduced.

The present invention achieves this objective using features of independent claims.

The present invention is based on the technical teaching that it is possible to easily reduce the actual cost of an imaging device while keeping the imaging quality at least constant, if a plurality of optical elements are assigned to a first sub-group of the projection device and with regard to imaging (e.g. The pattern of the reticle is imaged onto the substrate) and only supports a relatively low maximum control bandwidth. This initially leads to an increase in imaging aberrations due to the reduced adjustment dynamics of the first sub-group of optical elements, which results from the fact that it is no longer possible to quickly correct deviations between the optical elements of the first sub-group and their target states. . This imaging aberration is then at least partially compensated by one or more additional optical elements, which are actuated with a suitably high control bandwidth, also relevant for imaging, and to be assigned to the second subgroup of the projection device. Here, the spacing of the control bandwidth ranges of the maximum control bandwidths of the optical elements of the first and second subgroups is significantly different, so that a clearly perceptible difference is obtained with respect to the actual cost of the optical elements of the first subgroup. Cost savings.

The optical elements of the first subgroup can be configured to be relatively lighter and simpler due to their lower required maximum actuation control bandwidth. This also has a positive impact on the out-of-pocket costs required for the actuator system, i.e. for example the active support provided by these optical elements. Support embodiments of the optical elements of the first subgroup may also be referred to as floating supports or low-stiffness supports, since they react only relatively slowly or sluggishly to deviations from the target state. It is then usually sufficient to detect the pose (i.e. the position and/or orientation) of at least the first subgroup of these optical elements relatively accurately in the degrees of freedom relevant for high imaging quality (up to all six spatial degrees of freedom) , and then use this information to drive an actuator system of associated optical elements of the second subgroup.

The relevant optical elements of the second subgroup are then preferably optical elements that are in any case smaller and lighter, and for which the required high dynamics of actuation can be obtained at relatively low outlay. The support for the optical elements of the second subgroup here can also be called high-stiffness support, since there is a relatively fast or flexible response to the corresponding provision of the target state.

In this case, it may be sufficient for the second subgroup to contain only a single optical element (ie, a single correction element); however, a plurality of optical elements may also be used for correction purposes. A plurality of optical elements may be advantageous, particularly since correction of different imaging aberrations is performed by different correction elements, thus reducing the complexity of the actuator system for these correction elements. However, the correction of a specific imaging aberration can equally be distributed among a plurality of correction elements. This may also reduce the complexity of the actuator system for these correction elements. Reference is made expressly to the fact that the term "imaging aberration" as used in this specification may suitably include a plurality of different types of aberrations, which together describe the overall imaging quality of the image.

To correct imaging aberrations, it may be sufficient to imprint the corresponding deformation of its optical surface on the correction element or to appropriately pose the correction element according to the relevant degrees of freedom (up to all six spatial degrees of freedom). Essentially, combined correction can also be achieved through deformation and attitude control. In this case, it is not necessary to use only one or a plurality of correction elements to achieve complete correction of imaging aberrations. Likewise, other components involved in imaging may be used for correction purposes, such as the reticle or substrate (or its relative holding device), and its actuator system may be relatively controlled to obtain the smallest possible imaging image in the sum of the corrections Poor (within the error budget specified for a single imaging or imaging device).

It will be further understood that any relevant imaging aberrations can be corrected individually or in any combination; for example, this can be what is known as the line-of-sight error (LoS error), that is, the imaging of a point in the object plane relative to the point in the image plane. position error of the target position) and/or so-called wavefront aberration. This may be achieved entirely by appropriate actuation of the correction element or by coordinated actuation of a plurality of correction elements and optional additional components (eg, reticle and/or substrate).

Therefore, according to one aspect, the present invention relates to an optical configuration of a lithography imaging device, particularly for using light in the extreme ultraviolet (EUV) range, comprising an optical element group, a support structure, an active support device and control device. The optical element group includes a plurality of N optical elements supported on a support structure by an active support device. Herein, the active support device includes an active support unit for each optical element in the optical element group, the active support unit being configured to adjustably support the optical element on the support structure under the control of the control device. The optical element group includes a first subgroup having a plurality of M first optical elements and a second subgroup having a plurality of K second optical elements. The control means and the first active support unit assigned to the respective first optical element are configured to adjust the first optical element in at least one degree of freedom (up to all six spatial degrees of freedom) using a maximum control bandwidth within the first control bandwidth range. Furthermore, the control device and a second active support unit assigned to the respective second optical element are configured to adjust and/or in at least one degree of freedom (up to all six spatial degrees of freedom) using a maximum control bandwidth within the second control bandwidth range. Or deform the second optical element. The first control bandwidth range is lower than and spaced apart from the second control bandwidth range. Herein, the interval is at least 50% of the upper limit of the first control bandwidth range, preferably at least 100%, further preferably at least 125% and/or at least 40 Hz to 80 Hz, preferably 50 Hz to 175 Hz, more preferably 75 Hz to 125 Hz . In this way, the actual cost of the optical elements and their supports for the first subgroup can be significantly reduced, while ensuring sufficiently high imaging quality.

In principle, the two control bandwidth ranges can be positioned as desired and can have any desired size of bandwidth span (i.e. the variation of the maximum control bandwidth within which they lie), as long as the out-of-pocket cost of the optical elements of the first sub-group is available Relatively significant reduction. In some variations, the first control bandwidth ranges from 50 Hz to 180 Hz, preferably from 75 Hz to 160 Hz, further preferably from 90 Hz to 120 Hz. Additionally or alternatively, the second control bandwidth range may range from 180 Hz to 260 Hz, preferably from 200 Hz to 250 Hz, further preferably from 220 Hz to 250 Hz. Both can significantly reduce the out-of-pocket cost of optical components of the first subgroup while maintaining high image quality.

In some variations, the control device is connected to a capture device, wherein the capture device is configured to capture at least first pose information of the first optical element, the pose information representing the position of the first optical element. The respective position and/or orientation relative to a reference in at least one degree of freedom (and up to all six spatial degrees of freedom). In this regard, it is often possible to simply use already existing sensor systems (e.g. for adjustment of high control bandwidths) without thereby increasing out-of-pocket costs. The first attitude information can then be utilized with appropriate actuation of at least one second optical element (and optionally other components related to imaging, as described above) to correct for imaging aberrations caused by actuation of the first optical element caused by the decrease in dynamics.

Additionally or alternatively, the capturing device may be configured to capture first deformation information for at least the first optical element, the deformation information representing respective deformations of the first optical element in at least one degree of freedom. The process herein may be similar to the acquisition and use of the first posture information just described, so reference may be made to the above specific embodiments in this regard. Capturing deformation information is particularly advantageous because larger or heavier optics are still able to respond to relatively large deformations during operation, potentially having a significant impact on imaging aberrations, even when supporting maximum control bandwidth reduction (leading to a reduction in the acceleration acting on it).

Additionally or alternatively, the capture device may be configured to capture imaging aberration information, which represents the imaging aberration of the imaging device. The process here can also be similar to the acquisition and use of the first posture information or the first deformation information just described, so in this regard, reference can also be made to the above-mentioned specific embodiments.

In the aforementioned case, the control device is then configured to drive at least one second active support unit based on the first posture information and/or based on the first deformation information and/or based on the aberration information as mentioned above.

In an advantageous variant, the group of optical elements causes imaging aberrations of the imaging device during operation, wherein the control device is configured, during the imaging aberration correction step, alone or in combination with at least one additional component of the imaging device, to drive at least one first The two active support units make it possible to at least reduce the imaging aberration, and especially to basically eliminate the imaging aberration. In principle, imaging aberrations can be corrected in any suitable manner using at least one second active support unit and corresponding actuation of at least one additional component of the selective imaging device.

In some variants, aberrations are corrected (selectively only) in the aberration correction step by deformation of at least one second optical element having a maximum control bandwidth (from the second control bandwidth range). To this end, at least one second active support unit can have an active deformation unit, which is driven by the control device with the maximum control bandwidth of the second optical element in at least one degree of freedom (up to all six spatial degrees of freedom). ) to set the deformation of the second optical element specified. Thus, a so-called correction accuracy can be specified for the second optical element and then set using appropriate actuation of the opposing second active support unit on the specified second optical element.

It should be understood that the attitude of the second optical element need not be set to the maximum control bandwidth from the second control bandwidth range. On the contrary, in these cases, the attitude of the second optical element with the largest control bandwidth can also be adjusted from the first control bandwidth range, that is, the second optical element with the largest control bandwidth can be adjusted only from the second control bandwidth range. Deformation of components. Therefore, it may be the case that one or more optical elements are part of a first subgroup (since the attitude of the associated optical element is adjusted by the maximum control bandwidth from the first control bandwidth range) and a second subgroup of Part of it (because the deformation of the relevant optical elements is adjusted by the maximum control bandwidth from the second control bandwidth range). However, in some other variations, mutual exclusion may also be provided for the first and second subgroups, so that opposing optical elements can only be part of the first subgroup or only part of the second subgroup .

Additionally or alternatively, however, aberrations can also be corrected in an aberration correction step (only optionally) by attitude adaptation of at least one second optical element with a maximum control bandwidth (from the second control bandwidth range). To this end, at least one second active support unit may have an active attitude control unit, which is driven by the control device to set the designated second second optical element in at least one degree of freedom with the maximum control bandwidth of the second optical element. The location and/or orientation of optical components. Therefore, it is also possible to specify a so-called corrective attitude for the second optical element and then set it using an appropriate drive of the opposite second active support unit on the specified second optical element. In this case, it should be understood that the correction accuracy and the superposition of the correction attitude can also be specified.

As mentioned many times before, the control device can of course selectively carry out further correction of aberrations (based on the information captured using the capture device as described above) by actuating at least one additional component of the imaging device (for example, such as a mask device object device, and/or image device similar to the substrate device), in order to obtain the desired low imaging aberration as a whole. In a preferred variant, the at least one additional component of the imaging device is an image device (eg a substrate device) or an object device (eg a mask device) of the imaging device.

The control information required for driving the associated second active support unit (and optional additional components) can in principle be determined in any desired manner. Preferably, the control device in the aberration correction step uses the stored correction model to drive at least one second active support unit, and selectively uses at least one additional component of the imaging device to at least reduce the imaging aberration, in particular to substantially to eliminate imaging aberrations. In this case, the calibration model may provide control information for driving at least one second active support unit based on the first attitude information. Additionally or alternatively, the calibration model may provide control information for driving at least one second active support unit based on the first deformation information. Likewise, the correction model may additionally or alternatively provide control information for driving at least one second active support unit based on the aberration information. In this case, a correction model may be optionally provided, in each case using the control information for driving at least one additional part of the imaging device based on the first attitude information and/or the first deformation information and/or the imaging aberration information. Active third support unit of the component. In this way, overall imaging aberrations can be corrected or reduced as comprehensively as possible in a particularly simple and cost-effective manner.

In principle, the calibration model can be determined in any suitable desired way. Therefore, it can be established purely theoretically based on purely numerical modeling of the optical device configuration and the selective overall imaging device. Likewise, it can be established based on measurements of optical configurations and selective overall imaging devices (where this relates at least to comparable or structurally identical optical configurations or imaging devices, but preferably to the specific optical configuration or imaging device itself) . Of course, mixtures of these two extremes are possible and often particularly advantageous.

In principle, the calibration model can be a static model that remains unchanged at least during a relatively long period of operation. Preferably, this is an adaptive model that intermittently adapts the optical configuration or actual conditions of the imaging device. In this process, it is particularly possible to implement adaptive algorithms that are triggered by certain temporal events (for example, at certain specified time intervals) and/or make use of non-temporal events (beginning and/or end of operations, lighting devices and /or changes in the settings of the projection device, reaching certain specified operating parameters, such as the temperature of certain components, exceeding the aberration tolerance, etc.), check the effectiveness of aberration correction, and make relative corrections to the correction model.

In some advantageous variants, the control device is caused to be configured to correct the correction model in the model correction step based on at least one imaging aberration information item, the imaging aberration information item appearing in the aforementioned imaging aberration correction step, in particular is based on imaging aberration information emerging from previous imaging aberration correction steps. In this process, optionally, the correction can also include incorporating a plurality of imaging aberration information items AFI from a plurality of (optionally direct) consecutive imaging steps, for example, in order to take into account the development of imaging aberrations over time, and perform corrections Adequate calibration of the model. Then, the control device is configured to use the correction model corrected in the previous model correction step in the imaging aberration correction step. In this way, the adaptive correction model KM can be implemented in a particularly advantageous manner.

It can be understood that in principle, the acquisition device can only acquire the aforementioned relative acquisition variables or information for the first subgroup. And these can activate the second subgroup and optionally other component(s). However, it is preferred that a similar retrieval behavior also exists at or for the second subgroup, for particularly advantageous and effective corrections.

In some variations, the acquisition device is therefore configured to acquire second attitude information of at least one second optical element, the second attitude information representing at least one second optical element relative to the reference in at least one degree of freedom (up to all six position and/or orientation in three spatial degrees of freedom). Additionally or alternatively, the capturing device may be configured to capture second deformation information of at least one second optical element, the second deformation information representing at least one second optical element in at least one degree of freedom (up to all six spatial degrees of freedom). deformation below. In this case, the control device is then configured in each case to drive at least one second active support unit based on the second attitude information and/or based on the second deformation information.

In some variations with the above correction model, the correction model provides control information for driving at least one second active support unit based on the second attitude information. Additionally or alternatively, the calibration model may provide control information for driving at least one second active support unit based on the second deformation information. In this case, it is particularly possible again to configure the control device to perform correction in a model correction step, a correction model based on aberration information from a previous aberration correction step, in particular based on imaging aberrations from a previous imaging aberration correction step. information to perform this correction. Then, the control device is configured to use the correction model corrected in the model correction step in the imaging aberration correction step.

In principle, the optical configurations described herein can be used with imaging devices of any design or composition. In particular, the group of optical elements may include any desired number of optical elements. The same applies to the division of the group of optical elements into first and second subgroups. Preferably, the plural number N is equal to 2 to 12, preferably equal to 4 to 10, more preferably equal to 6 to 8. Additionally or alternatively, the plural number M may be equal to 2 to 10, preferably equal to 3 to 8, more preferably equal to 4 to 6. Additionally or alternatively, the final plural number K may be equal to 1 to 12, preferably equal to 4 to 10, more preferably equal to 6 to 8. Thus, for example, only a single correction element may be sufficient to obtain the desired smaller imaging aberrations (optionally together with actuation of one or more additional components as described). In any case, all these situations lead to particularly advantageous arrangements in which the smallest possible imaging aberrations are possible, so that the outlay of the first subgroup becomes relatively low.

Optical elements can in principle be assigned to the first and second subgroups according to any desired criteria. Typically, elements that are found to be particularly difficult to adjust with the maximum control bandwidth of the second control bandwidth range are assigned to the first subgroup. Furthermore, certain optical elements may be assigned to the first subgroup, ie they may be actuated with the maximum control bandwidth from the second control bandwidth range. Even for those optics, this can reduce out-of-pocket costs. As mentioned before, in the case of the second subgroup it is optionally also possible to adjust the attitude of the second optical element with the largest control bandwidth from the first control bandwidth range, that is to say in that case only the Variation of the second optical element having a maximum control bandwidth from a second control bandwidth range.

A particularly advantageous arrangement occurs if the first subgroup contains the largest optical element of the optical element group and/or the heaviest optical element of an optical element group. Additionally or alternatively, the first subgroup may include the second largest optical element in the group of optical elements and/or the second heaviest optical element in the group of optical elements. Also additionally or alternatively, the second subgroup may comprise the smallest optical element in a group of optical elements and/or the lightest optical element in a group of optical elements. Additionally or alternatively, the second subgroup may include the second smallest optical element in a group of optical elements and/or the second lightest optical element in a group of optical elements.

The present invention also relates to an optical imaging device, particularly a lithography optical imaging device, which includes an illumination device with a first optical element group, an object device for receiving an object, and a second optical element group. Projection device, and an image device. The lighting device is configured to illuminate the object, and the projection device is configured to project an image representation of the object onto the imaging device. In this case, the projection device includes at least one optical configuration according to the invention as described above. This makes it possible to realize the variants and advantages described above with respect to the optical configuration to the same extent, so that reference is made in this regard to the above explanation to avoid repetition.

The invention also relates to a method for supporting an optical element group on a support structure of a lithographic imaging device, in particular using light in the extreme ultraviolet (EUV) range, wherein the optical element group contains a plurality of N optical elements, which An active support device is used to support a plurality of N optical elements on a support structure, wherein the optical element group includes a first subgroup with a plurality of M first optical elements and a second subgroup with a plurality of K second optical elements. group. Each optical element in an optical element group is adjustably supported on the support structure using an active support unit. In this case, the opposing first optical elements are adjusted in at least one degree of freedom by a designated first active support unit having a maximum control bandwidth within the first control bandwidth range. The opposing second optical element is adjusted and/or deformed in at least one degree of freedom by a designated second active support unit having a maximum control bandwidth within the second control bandwidth range. The first control bandwidth range is lower than and spaced apart from the second control bandwidth range. The interval is at least 50% of the upper limit of the first control bandwidth range, preferably at least 100%, further preferably at least 125% and/or at least 40 Hz to 80 Hz, preferably 50 Hz to 175 Hz, further preferably 75 Hz to 125 Hz. This makes it possible to realize the variants and advantages described above with respect to the optical configuration to the same extent, so that reference is made in this regard to the above explanation to avoid repetition.

The invention also relates to an optical imaging method, in particular for lithography, in which an illumination device with a first optical element group illuminates the object, and a projection device with a second optical element group projects an image representation of the object. to the imaging device. In this case, at least the optical elements of the second optical element group of the projection device are supported by the method for supporting the optical element group according to the present invention. This also makes it possible to realize the variants and advantages described above with respect to the optical configuration to the same extent, so that reference is made to the above explanation in this regard to avoid repetition.

Further aspects and exemplary embodiments of the present invention will become more apparent from the following description of the patent claims and preferred exemplary embodiments with reference to the accompanying drawings. All combinations of disclosed features, whether or not the subject of a patent, are included within the scope of the invention.

Preferred exemplary embodiments of a lithographic projection exposure apparatus 101 according to the present invention, including preferred exemplary embodiments of optical configurations according to the present invention, are described below with reference to FIGS. 1 and 2 . In order to simplify the following explanation, the x, y, z coordinate system is shown in the drawing, and the z direction is parallel to the direction of gravity. Accordingly, the x- and y-directions extend horizontally, with the x-direction extending vertically into the drawing plane in Figure 1. It goes without saying that any desired other directions of the x, y, z coordinate system can be selected in further configuration.

The basic components of the projection exposure apparatus 101 are first described by way of example with reference to FIG. 1 . However, the description of the basic structure of the projection exposure apparatus 101 and its components should not be construed as being limited thereto.

The illumination device or illumination system 102 of the projection exposure apparatus 101 contains a radiation source 102.1 and also a group of optical elements in the form of an illumination optical unit 102.2 for illuminating an object field 103.1 (shown schematically). The object field 103.1 is located in the object plane 103.2 of the object device 103. In this case, a multiplication mask 103.3 (also called a mask) arranged in the object field 103.1 is illuminated. The reticle 103.3 is supported by the reticle carrier 103.4. The illumination displacement driver 103.5 can be used to move the reticle carrier 103.4, particularly along one or more scanning directions. In this example, this scanning direction extends parallel to the y-axis.

The projection exposure apparatus 101 further comprises a projection device 104 with a further group of optical elements in the form of a projection optical unit 104.1. The projection optics unit 104.1 serves to image the object field 103.1 into an image field 105.1 (as schematically shown), which is located in the image plane 105.2 of the imaging device 105. Image plane 105.2 extends parallel to object plane 103.2. Alternatively, it is possible that there is an angle other than 0 degrees between the object plane 103.2 and the image plane 105.2.

During exposure, the structures on the reticle 103.3 are imaged onto a substrate photosensitive layer in the form of the wafer 105.3, which is arranged at the image plane 105.2 in the area of the image field 105.1. Wafer 105.3 is supported by a substrate carrier or wafer carrier 105.4. The wafer displacement drive 105.5 can be used to move the wafer carrier 105.4, especially in the y direction. First, the mask displacement driver 103.5 is used to move the mask 103.3, and secondly, the wafer displacement driver 105.5 is used to move the wafer 105.3, which can occur synchronously with each other. Such synchronization can be achieved, for example, using a common control device 106 (shown only very schematically in FIG. 1 and without a control path).

The radiation source 102.1 is an EUV radiation source (Extreme Ultraviolet Radiation Source). In particular, the radiation source 102.1 can emit EUV radiation 107, which is also referred to below as used radiation or illumination radiation. In particular, the radiation used has a wavelength range between 5 nm and 30 nm, in particular a wavelength of approximately 13 nm. The radiation source 102.1 may be a plasma source, such as a laser plasma (LPP) source or a gas discharge plasma (DPP) source. It can also be a synchrotron-based radiation source. However, the radiation source 102.1 may also be a free electron laser (FEL).

Since the projection exposure apparatus 101 is operated using light with an operating wavelength in the EUV range, the optical elements used are only reflective optical elements. In further configurations of the invention, it is of course also possible (in particular depending on the wavelength of the illuminating light) to use any type of optical element (refraction, reflection, diffraction) alone or in any desired combination of optical elements.

Illumination radiation 107 emitted from radiation source 102.1 is focused by concentrator 102.3. Concentrator 102.3 may be a concentrator having one or more elliptical and/or hyperboloid reflective surfaces. The illumination radiation 107 can be incident at grazing incidence (GI) on at least one reflective surface of the condenser 102.3, ie at an angle of incidence greater than 45 degrees, or at normal incidence (NI), ie at an angle of incidence less than 45 degrees. The concentrator 102.3 can be structured and/or coated on the one hand to optimize the reflectivity of the radiation used and on the other hand to suppress extraneous light.

Downstream of the condenser 102.3, the illumination radiation 107 is propagated by an intermediate focus in the intermediate focus plane 107.1. The intermediate focal plane 107.1 may represent the separation between the illumination optical unit 102.2 and the radiation source module 102.4 containing the radiation source 102.1 and the condenser 102.3.

Along the beam path, the illumination optical unit 102.2 includes a polarizer 102.5 and a downstream first facet mirror 102.6. The polarizer 102.5 may be a plane polarizer or, alternatively, a reflector having a beam influencing effect beyond a pure deflection effect. Alternatively or in addition, the polarizer 102.5 may be configured as a spectral filter that at least partially separates, known as extraneous light from the illuminating radiation 107, its wavelength of light being different from the wavelength of light used. If the optically active surface of the first facet mirror 102.6 is arranged in the plane region of the illumination optical unit 102.2 that is optically conjugated to the object plane 103.2 as a field plane, the first facet mirror 102.6 is also called a field facet reflector. Mirror. The first facet mirror 102.6 contains multiple individual first facets 102.7, which may also be called field facets. These first facets 21 and their optical surfaces are only shown very schematically in FIG. 1 by dashed outlines 102.7.

The first facet 102.7 can be embodied as a macroscopic facet, in particular a rectangular facet or a facet with a curved edge profile or a partially circular edge profile. The first facet 102.7 can be embodied as a planar facet or alternatively as an optical face with a convex or concave curvature.

It is known, for example, from patent case DE 10 2008 009 600 A1, the entire disclosure of which is incorporated herein by reference, that the first facet 102.7 itself can also be composed in each case of a plurality of individual mirrors, in particular of a plurality of Micromirror. In particular, the first facet mirror 102.6 can be configured as a microelectromechanical system (MEMS system), details see for example DE 10 2008 009 600 A1.

In this example, between the condenser 102.3 and the polarizer 102.5, the illumination radiation 107 propagates horizontally, that is to say in the y-direction. However, it goes without saying that in the case of other variants different arrangements can also be chosen.

In the beam path of the illumination optical unit 102.2, the second facet mirror 102.8 is arranged downstream of the first facet mirror 102.6. If the second facet mirror 102.8 is arranged in the region of the pupil plane of the illumination optical unit 102.2, the second facet mirror 102.8 is also called a pupil facet mirror. The second facet mirror 102.8 may also be arranged at a certain distance from the pupil plane of the illumination optical unit 102.2. In this case, the combination of the first facet mirror 102.6 and the second facet mirror 102.8 is also called a specular reflector. Specular reflectors are known, for example, from patent cases US 2006/0132747 A1, EP 1 614 008 B1 and US 6,573,978 (the entire disclosures of each of which are incorporated herein by reference).

The second facet mirror 102.8 also contains a plurality of second facets. These second facets are only shown very schematically in FIG. 1 by dashed outlines 102.9. In the case of pupil facet mirrors, the second facet 102.9 is also called the pupil facet. In principle, the second facet 102.9 can have the same design as the first facet 102.7. In particular, the second facet 102.9 can also be a macrofacet, which can have circular, rectangular or hexagonal boundaries, for example. Alternatively, the second facet 102.9 may be a facet consisting of micromirrors. The second facet 102.9 may also have a planar reflective surface or alternatively a reflective surface with a convex or concave curvature. In this regard, reference is also made to patent case DE 10 2008 009 600 A1.

In this example, the illumination optical unit 102.2 thus forms a two-sided system. This basic principle is also called a compound-eye concentrator (or compound-eye integrator). In certain variants it may be advantageous to configure the optical surface of the second facet mirror 102.8 not entirely in a plane that is optically conjugate to the pupil plane of the projection optical unit 104.1.

In a further embodiment of the illumination optics unit 102.2 that is not shown, a transmission optics unit 102.10 (shown only schematically) is particularly useful for imaging the first facet 102.7 into the object field 103.1, which can be configured in In the beam path between the second facet mirror 102.8 and the object field 103.1. The transmission optics unit 102.10 can have exactly one mirror, or alternatively two or more mirrors, which can be arranged one after another in the beam path of the illumination optics unit 102.2. In particular, the transmission optical unit 102.10 may include one or two normal incidence mirrors (NI mirrors) and/or one or two grazing incidence mirrors (GI mirrors).

In the specific embodiment shown in Figure 1, the illumination optical unit 102.2 may have exactly three reflectors downstream of the condenser 102.3, specifically a polarizer 102.5, a first facet reflector 102.6 (for example, field facet reflector mirror) and a second facet mirror 102.8 (e.g. pupil facet mirror). In a further specific embodiment of the illumination optical unit 102.2, the polarizer 102.5 is not needed, so the illumination optical unit 102.2 can have two reflectors just downstream of the condenser 102.3, specifically the first facet reflector 102.6 and the second reflector. Dictionary mirror 102.8.

Each first facet 102.7 is imaged into the object field 103.1 by the second facet mirror 102.8. The second facet mirror 102.8 is the last beam shaping mirror in the beam path upstream of the object field 103.1 or indeed the last mirror for the illuminating radiation 107. Imaging the first facet 102.7 into the object plane 103.2 by the second facet 102.9 or using the second facet 102.9 and the transmission optical unit 102.10 is usually only an approximate imaging.

The projection optical unit 104.1 contains a plurality of mirrors Mi, numbered according to their arrangement in the beam path of the projection exposure device 101. In the example shown in Figure 1, the projection optical unit 104.1 contains six mirrors M1 to M6. Alternatively there could be 4, 8, 10, 12 or any other number of mirrors Mi. Each of the penultimate mirror M5 and the last mirror M6 has a channel opening for illumination radiation 107 (not shown in more detail). In this example, the projection optical unit 104.1 is a double-shielded optical unit. The image-side numerical aperture NA of the projection optical unit 104.1 is greater than 0.5. In particular, the image side numerical aperture NA can also be greater than 0.6. For example, the image-side numerical aperture NA may be 0.7 or 0.75.

The reflecting surface of the mirror Mi may be implemented as a free-form surface without an axis of rotational symmetry. Alternatively, the shape of the reflecting surface of the reflecting mirror Mi may be designed as an aspherical surface having only one axis of rotational symmetry. Like the reflector of the illumination optical unit 102.2, the reflector Mi can have a highly reflective coating for the illumination radiation 107. These coatings can be designed as a plurality of coatings (multilayer coatings), in particular they can be configured as alternating layers of molybdenum and silicon.

In this example, the projection optical unit 104.1 has a large object-image offset in the y-direction between the y-coordinate of the center of the object field 103.1 and the y-coordinate of the center of the image field 105.1. In the y direction, this object-image offset may be approximately the same as the distance z between the object plane 103.2 and the image plane 105.2.

The projection optical unit 104.1 can in particular have a variant form. It has particularly different imaging ratios βx, βy along the x-direction and the y-direction. The two imaging ratios βx and βy of the projection optical unit 104.1 are preferably (βx, βy)=(+/-0.25, +/-0.125). A positive imaging ratio β means that there is no image inversion imaging. The negative sign of the imaging ratio β indicates that the image is inverted. In the present example, the dimensions of the projection optical unit 104.1 thus result in a reduction of 4:1 in the x-direction (ie, perpendicular to the scanning direction). In comparison, the size of the projection optical unit 104.1 along the y direction (that is, along the scanning direction) is reduced by a ratio of 8:1. Other imaging ratios are equally possible. It is also possible to have imaging scales with the same sign and the same absolute value along the x- and y-directions, such as an absolute value of 0.125 or 0.25.

The number of intermediate image planes in the x-direction and y-direction in the beam path between the object field 103.1 and the image field 105.1 may be the same or different, depending on the design of the projection optical unit 104.1. Examples of projection optical units with different numbers of such intermediate images in the x- and y-directions are known from patent case US 2018/0074303 A1, the entire disclosure of which is incorporated herein by reference.

In each case, one of the pupil facets 102.9 in this example exactly designates one of the field facets 102.7 to form in each case an illumination channel for illuminating the object field 103.1. This produces illumination in particular according to the Kohler principle. Use field facets 102.7 to decompose the far field into multiple object fields 103.1. The field facets 102.7 generate a plurality of images of intermediate focus on the pupil facets 102.9 respectively assigned to them.

Each of the field facets 102.7 is imaged onto the reticle 103.3 through a designated pupil facet 102.9, where the overlay image and thus overlay illumination of the object field 103.1 are present. The lighting of object field 103.1 is particularly as uniform as possible. It preferably has a uniformity error of less than 2%. Field uniformity can be achieved by superimposing different illumination channels.

The illumination of the entrance pupil of the projection optical unit 104.1 can be geometrically defined by arranging the pupil facet 102.9. The intensity distribution in the entrance pupil of the projection optical unit 104.1 can be set by selecting an illumination channel, in particular a subset of the pupil facets 102.9 that guide the light. This intensity distribution is also called the lighting setup. An equally preferred pupil uniformity in partial areas of the illumination pupil of the illumination optical unit 102.2 illuminated in a defined manner can be achieved by reassigning the illumination channel. In the case of actively adjustable facets, the above-mentioned settings can be made in each case using a corresponding control of the control device 106 .

Further aspects and details regarding the illumination of the object field 103.1 and in particular the entrance pupil of the projection optical unit 104.1 are described below.

In particular, the projection optical unit 104.1 can have a concentric entrance pupil. The latter may be accessible or inaccessible. The pupil facet mirror 102.8 is generally unable to accurately illuminate the entrance pupil of the projection optical unit 104.1. When imaging the center of the pupil facet mirror 102.8 telecentrically onto the projection optics unit 104.1 on the wafer 105.3, the aperture rays typically do not intersect at a single point. However, a region can be found where the distance between pairs of determined aperture light lines becomes minimum. This region represents the entrance pupil or the region in real space conjugated to it. In particular, this region has finite curvature.

For some variations, the projection optics unit 104.1 may have different entrance pupil poses for the tangential beam path and the sagittal beam path. In this case, the imaging optical element, in particular the optical component of the transmission optical unit, should be arranged between the second facet mirror 102.8 and the reticle 103.3. With this optic, different postures of the tangential entrance pupil and the sagittal entrance pupil can be considered.

In the component arrangement of the illumination optical unit 102.2 shown in FIG. 1, the second facet mirror 102.8 is arranged in a surface conjugate to the entrance pupil of the projection optical unit 104.1. The first facet mirror 102.6 (field facet mirror) defines a first principal plane of extension of its optical surface, which in this example is configured inclined relative to the object plane 103.2. In this example, the first main extension plane of the first facet mirror 102.6 is arranged inclined relative to the second main extension plane defined by the optical surface of the polarizer 102.5. In this example, the first principal plane extending from the first facet mirror 102.6 is also configured to be inclined relative to the third principal plane extending bounded by the optical surface of the second facet mirror 102.8.

For example, lighting device 102 and/or projection device 104 may include one or more optical configurations 108 in accordance with the present invention, as described below.

The projection device 104 forms an optical arrangement according to the invention, having an optical element group G in the form of a projection optical unit 104.1, formed from a plurality N (N equal to 6) of optical elements, in particular mirrors Mi, that is in In this case mirrors M1 to M6. The opposing mirrors M1 to M6 are supported by active support means 108 on a support structure 104.2 of the projection device 104 (shown only very schematically). In this case, the active support device 108 includes an active support unit 108.1, 108.2 for each optical element M1 to M6 in the optical element group G, which active support unit is configured to under the control of the control device 106 The opposing optical elements M1 to M6 are adjustably supported on the support structure 104.2.

In this example, the group G of optical elements M1 to M6 of the projection optical unit 104.1 includes a first subgroup UG1 with a plurality of M first optical elements (M equals 4) and a first subgroup UG1 with a plurality of K (K equals 2). Second subgroup UG2 of second optical elements. In this example, the mirrors M2, M4, M5 and M6 belong to the first subgroup UG1, while the mirrors M1 and M3 belong to the second subgroup UG2. It goes without saying that any other means of designation can also be provided in the case of other variants. For example, in that case, the mirror M1 can also be assigned to the first subgroup UG1, causing the second subgroup UG2 to consist only of the mirror M3.

As will be explained below based on the mirror M6 and the assigned first active support unit 108.1, the control means 106 and the first active support unit 108.1 assigned to the opposite first optical elements M2, M4, M5, M6 (for the sake of clarity , no active support unit is depicted for mirrors M2, M4, M5) configured with a maximum control bandwidth RBM1 within a first control bandwidth range RBB1 at least one degree of freedom DOF (up to all six degrees of freedom DOF in space) Adjust the first optical elements M2, M4, M5, M6. As will be explained further below based on the mirror M3 and the second active support unit 108.2 assigned to the opposite second optical element M1, M3, the control device 106 and the second active support unit 108.2 assigned to the opposite second optical element M1, M3 are configured to operate in at least one degree of freedom DOF Adjust and/or deform the second optical elements M1, M3 (up to all six degrees of freedom DOF in space), wherein the maximum control bandwidth RBM2 is within the second control bandwidth range RBB2. In this case, it is understood that the optical elements M1 to M6 may in each case be provided with maximum control bandwidths RBM1 and RBM2 that differ from each other as required, depending on the requirements of the imaging device. However, the same maximum control bandwidth RBM1 or RBM2 can also be provided for each optical element of the opposite subgroups UG1 and UG2.

The first control bandwidth range RBB1 is lower than the second control bandwidth range RBB2 and is separated from the second control bandwidth range RBB2 by an interval RBA. Herein, the spacing RBA is at least 50% of the upper limit of the first control bandwidth range RBB1, preferably at least 100%, further preferably at least 125% and/or at least 40 Hz to 80 Hz, preferably 50 Hz to 175 Hz, more preferably 75 Hz to 125 Hz.

Therefore, the first optical elements M2, M4, M5, M6 of the first subgroup UG1 are supported by the relatively small maximum control bandwidth RBM1. This initially leads to an increase in imaging aberrations due to the reduced adjustment dynamics of the optical elements M2, M4, M5, M6 of the first subgroup UG1, since the optical element M2 of the first subgroup UG1 can no longer be corrected fast enough. , caused by the deviation of M4, M5 and M6 from their target states. As will be explained below, this imaging aberration is then at least partially compensated for by a second subgroup UG2 of optical elements M1, M3, which are actuated with a relatively high control bandwidth RBM2.

Since the maximum control bandwidth RBM1 required for driving is low, the optical elements M2, M4, M5, and M6 of the first subgroup UG1 can be configured to be relatively lighter and simpler. This also has a positive impact on the out-of-pocket costs required to operate its designated actuator system, ie the corresponding first active support unit 108.1. In this way, the actual cost of the optical elements M2, M4, M5, M6 of the first subgroup UG1 and their support (that is, the first active support unit 108.1) can be significantly reduced, while ensuring high enough imaging quality.

In any case in this example, the relevant optical elements M1 and M3 of the second subgroup UG2 are smaller and lighter optical elements, so the second active support unit 108.2 can be used to compensate for imaging at a relatively small actual cost. High power required for aberrations.

In principle, as long as the actual costs of the optical components M2, M4, M5, and M6 of the first subgroup UG1 can be significantly reduced accordingly, the two control bandwidth ranges RBB1 and RBB2 can be positioned as needed and can have any desired span size. (i.e., a variant of RBB1 or RBB2 within which the maximum control bandwidth lies). In some variations, the first control bandwidth range RBB1 ranges from 50 Hz to 180 Hz, preferably from 75 Hz to 160 Hz, further preferably from 90 Hz to 120 Hz. Additionally or alternatively, the second control bandwidth range RBB2 may range from 180 Hz to 260 Hz, preferably from 200 Hz to 250 Hz, further preferably from 220 Hz to 250 Hz. The two can significantly reduce the actual cost of the optical components M2, M4, M5, and M6 of the first subgroup UG1, while maintaining high imaging quality.

In the present example, the control device 106 is connected to a capture device 109 (shown only very schematically in Figure 1 ), wherein the capture device 109 is configured in a conventional manner to capture at least the first optical elements M2, M4, M5 , the first attitude information LI1 of M6. The first attitude information represents the respective positions of the first optical elements M2, M4, M5, and M6 relative to the reference point R under at least one degree of freedom DOF (up to all six degrees of freedom DOF in space). location and/or orientation. In this regard, the sensor system 109 that is typically already present in conventional imaging devices can be easily used in any case (eg for adjustments with high control bandwidth), resulting in no increase in out-of-pocket costs in this regard.

In this example, the first posture information LI1 is used to realize the correction of imaging aberrations resulting from the dynamic actuation reduction of the first optical elements M2, M4, M5, M6, which is appropriately via the second active support unit 108.2 The second optical elements M1, M3 are actuated and optionally utilize corresponding actuation of additional imaging-related components, such as the object device 103 and/or the image device 105, as described above.

It may be sufficient to only retrieve the first attitude information LI1 and use it to drive the second active support unit 108.2. However, in this example, the capturing device 109 is also configured to capture the first deformation information DI1 for at least the first optical elements M2, M4, M5, M6. The first deformation information represents the first optical elements M2, M4, M5, Respective deformation of M6 in at least one degree of freedom (up to all six spatial degrees of freedom). The process here may be similar to the acquisition and use of the first posture information LI1 just described, so reference may be made to the above specific embodiments in this regard. Retrieving deformation information DI1 is particularly advantageous because during operation larger or heavier optical elements such as reflectors can Mirrors M2 and M6) are still able to respond to relatively large deformations, which may have a significant impact on imaging aberrations.

In addition, the capture device 109 of this example is also configured to capture imaging aberration information AFI, which represents the imaging aberration of the imaging device. This process may also be similar to the acquisition and use of the first posture information LI1 or the first deformation information DI1 just described, so please refer to the above specific embodiments for this.

In this specific embodiment, in the aberration correction step, the control device 106 is configured to drive the second active support unit 108.2 based on the first posture information LI1, the first deformation information DI1 and the imaging aberration information AFI, so that the projection exposure The overall imaging aberrations of the device 101 are kept as low as possible. In this process, the control device 106 can also drive the second active support unit 108.2 in combination with at least one additional component of the projection exposure device 101, such as the object device 103 and/or the image device 105, to at least reduce the imaging of the projection exposure device 101. Aberrations, particularly imaging aberrations of the projection exposure device 101 are substantially eliminated. This will be briefly described below based on the flow chart in Figure 2.

As can be understood from Figure 2, the process initially starts with step 110.1. It is then checked in step 110.2 whether imaging should be performed. If this is the case, the above-mentioned first posture information LI1 and first deformation information DI1 are determined in step 110.3. As will be explained in more detail below, the stored correction model KM is then used in step 110.4 to determine correction information KI in the control device 106 from the information of the acquisition device 109 . The control device 106 then uses this correction information KI to correctively drive the second active support unit 108.2 in an aberration correction step 110.5, selectively with at least one of the projection exposure devices 101 before or simultaneously with generating the image representation in the imaging step 110.6. Additional components such as object device 103 and/or image device 105 are combined. In a step 110.7, parallel to or subsequent to the imaging step 110.6, it is determined whether the actual imaging aberrations captured by the projection exposure device 101 are within certain specified tolerances, or whether this is not the case and therefore a model correction of the correction model KM is required. If this model correction is required, it is performed in step 110.9 based on the imaging aberrations of the projection exposure device 101 captured in step 110.7. In both cases, it is then checked in step 110.10 whether the process should be terminated. If it should terminate, the procedure ends at step 110.11. Otherwise jump back to step 110.2.

In some variations, in the imaging aberration correction step 110.5 (selectively only) by deformation of at least one of the second optical elements M1, M3 having the maximum control bandwidth RBM2 (from the second control bandwidth range RBB2) Correct imaging aberrations. To this end, the relevant second active support unit 108.2 has an active deformation unit (not depicted in more detail), which is driven by the control device 106 to set the specified second optical element with the maximum control bandwidth RBM2 of the second optical element M1 or M3 Deformation of element M1 or M3 in at least one degree of freedom DOF (up to all six degrees of freedom DOF). The control device 106 therefore assigns the so-called correction accuracy KP in this process to the second optical element M1 or M3 and then sets the control device 106 by appropriate actuation (via the control device 106 ) of the associated second active support unit 108.2 On the designated second optical element M1 or M3.

It should be understood here that the attitude of the second optical element M1 or M3 is not necessarily set to have the maximum control bandwidth RBM2 from the second control bandwidth range RBB2. On the contrary, in these cases, the attitude of the associated second optical element M1 or M3 with the maximum control bandwidth RBM1 from the first control bandwidth range RBB1 can also be adjusted, that is, only the attitude with the maximum control bandwidth RBM1 from the second control bandwidth range RBB2 is adjusted. The maximum control bandwidth is the deformation of the second optical element M1 or M3 of RBM2.

However, it is to be understood that in the imaging aberration correction step 110.5 (selective only ) to correct imaging aberrations. To this end, the associated second active support unit 108.2 can have an active posture control unit (not depicted in more detail), which is driven by the control device 106 in an aberration correction step 110.5 with the second optical element M1 or M3 The maximum control bandwidth RBM2 sets the position and/or orientation of the specified second optical element M1 or M3 in at least one degree of freedom DOF (up to all six spatial degrees of freedom DOF). A so-called correction position KL can therefore also be specified for the associated second optical element M1 or M3 and then set on the associated second optical element M1 or M3 by suitable actuation of the associated second active support unit 108.2. From this context, it is understood that the control device 106 can also be used to specify the superposition of the correction accuracy KP and the correction attitude KL.

As mentioned many times before, the control device 106 can of course selectively perform further aberration correction (based on the above information captured using the capture device) by actuating at least one additional component of the imaging device (eg, a reticle device or object device 103 and/or substrate device or image device 105) to generally obtain desired imaging with low imaging aberrations.

In principle, the control information, ie the correction information KI, required to drive the associated second active support unit 108.2 (and optional additional components 103, 105) can be determined in any desired manner. In this example, the control device 106 uses the stored correction model KM in an aberration correction step 110.5 to drive the associated second active support unit 108.2 and, optionally, at least one additional component 103, 105 of the imaging device 101 to At least the imaging aberration is reduced, and in particular, the imaging aberration is basically eliminated.

In this case, the correction model KM may provide control information or correction information KI for driving the associated second active support unit 108.2 based on the first attitude information LI1.

In this example, the correction model KM also provides control information or correction information KI for driving the associated second active support unit 108.2 based on the first deformation information DI1. Likewise, in some variations, the correction model may provide control information or correction information KI for driving the associated second active support unit 108.2 also based on the previous aberration information AFI. In this case, the correction model KM may selectively provide an active third component for driving the additional component 103 or 105 of the imaging device based on the first attitude information and/or the first deformation information and/or the imaging aberration information in each case. Three support units 103.5 or 105.5. In this way, the overall imaging aberration can be corrected or reduced as comprehensively as possible in a particularly simple and cost-effective manner.

In principle, the calibration model KM can be determined in any suitable desired way. It is therefore possible to have established the correction model KM purely theoretically based on purely numerical modeling of the optical configuration and selectivity of the entire imaging device 101 . The correction model KM can also be established based on measurements of the optical configuration and selectively the entire imaging device, where this relates at least to comparable or structurally identical optical configurations or imaging devices, but preferably to the specific optical configuration or imaging device 101 itself. In essence, a mixture of these two extremes can be, and often is, particularly advantageous.

In principle and as mentioned, the calibration model KM can be a static model that remains unchanged at least during a relatively long period of operation. Preferably, as in this example, this is an adaptive model that intermittently adapts the optical configuration or actual conditions of the imaging device 101, in particular in step 110.8. In this process, an adaptive algorithm may be implemented which in step 110.8 is determined only by specific temporal events (e.g., at certain specified intervals) and/or by non-temporal events (beginning and/or end of operation, lighting device and/or triggered by changes in the settings of the projection device, reaching certain specified operating parameters, such as the temperature of certain components, exceeding the imaging aberration tolerance, etc.), check the effectiveness of the aberration correction in step 110.9, and perform the correction The model is relatively calibrated.

In the present example, the control device 106 is therefore configured to correct the correction model KM in the correction step 110.9, the correction being based on at least one imaging aberration information item AFI arising from the previous imaging aberration correction step 110.5 (and in step 110.7 captured), in particular based on the imaging aberration information emerging from the immediately preceding imaging aberration correction step 110.5. In this process, a plurality of imaging aberration information items AFI from a plurality of (optionally direct) consecutive steps 110.7 may optionally also be included in the correction, for example in order to take into account imaging aberrations developing over time and to adequately correct the correction model KM. In this example, the control device 106 is configured to use the correction model KM corrected in the previous model correction step 110.9 in the imaging aberration correction step 110.5. In this way, the adaptive correction model KM can be implemented in a particularly advantageous manner.

It should be understood that the acquisition device 109 can in principle only acquire the above-mentioned corresponding acquisition variables or information of the first sub-group UG1, and these can be used to activate the second sub-group UG2 and optional (multiple) additional components 103, 105. However, in the present example, a similar acquisition is preferably performed at or for the second subgroup UG2 to obtain a particularly advantageous and effective correction in the imaging aberration correction step 110.5.

In this example, the capturing device 109 is therefore configured to capture the second posture information LI2 of the related second optical elements M1 and M3 in step 110.3, the second posture information indicating that the related second optical elements M1 and M3 are relative to each other. The position and/or orientation of a reference point R in at least one degree of freedom DOF (up to all six degrees of freedom DOF in space). Additionally, the capturing device is configured to capture second deformation information DI2 of the relevant second optical elements M1 and M3, where the second deformation information represents that the relevant second optical elements M1 and M3 are in at least one degree of freedom DOF (at most all Deformation under six spatial degrees of freedom (DOF). Then, in an aberration correction step 110.5, the control device 106 is configured to drive the associated second active support unit 108.2 also based on the second attitude information LI2 and based on the second deformation information DI2.

In this example, the correction model KM then also provides control information or correction information KI based on the second attitude information LI2 and the second deformation information DI2 to drive the related second active support unit 108.2.

It should be understood that, in principle, the optical configurations described herein may be used with imaging device 101 of any design or composition. In particular, optical element group G may contain any desired number of optical elements. The same applies to dividing the group of optical elements into first and second subgroups. Preferably, the plural number N is equal to 2 to 12, preferably equal to 4 to 10, more preferably equal to 6 to 8. Additionally or alternatively, the plural number M may be equal to 2 to 10, preferably equal to 3 to 8, more preferably equal to 4 to 6. Additionally or alternatively, the complex number K may ultimately equal 1 to 12, preferably 4 to 10, more preferably 6 to 8. Thus, for example, a single correction element may thus be sufficient to obtain a desired smaller imaging aberration (optionally together with actuation of the described additional component(s)). In any case, all these situations lead to particularly advantageous arrangements in which the first subgroup can have smaller imaging aberrations at relatively less out-of-pocket costs.

In principle, the optical elements M1 to M6 can be assigned to the first and second subgroups UG1 , UG2 according to any desired criteria. Typically, optical elements which are found to be particularly difficult to adjust with the maximum control bandwidth RBM2 of the second control bandwidth range RBB2 are assigned to the first subgroup UG1. Furthermore, certain optical elements can be assigned to the first subgroup UG1, ie they can be driven with the maximum control bandwidth RBM2 from the second control bandwidth range RBB2. This reduces out-of-pocket costs even for those optics. As mentioned before, in the case of the second subgroup UG2, it is also possible to selectively adjust the attitude of the second optical elements M1, M3 with the maximum control bandwidth RBM1 from the first control bandwidth range RBB1, that is, in In that case only the deformation of the second optical element M1 , M3 with the maximum control bandwidth from the second control bandwidth range RBB2 is adjusted.

Like in this example, the arrangement of the first subgroup UG1 is particularly advantageous if it contains the largest optical element M6 of the optical element group G, which in this case is also the heaviest optical element of the optical element group G . Additionally, the first subgroup UG1 includes the second largest optical element M2 in the optical element group G, which is also the second heaviest optical element in the optical element group G.

Furthermore, the second subgroup includes the smallest optical element M3 in the optical element group G, which is also the lightest optical element in the optical element group G. Additionally, the second subgroup UG2 includes the second smallest optical element M1 in the optical element group G, which is also the second lightest optical element in the optical element group G.

The above description of the invention is based solely on examples from the field of lithography. However, the present invention can of course also be used in any other optical applications desired, in particular in imaging methods at different wavelengths where similar problems arise with regard to active correction of imaging aberrations.

Furthermore, the present invention may be used in conjunction with processes for inspecting objects, such as so-called mask inspection, where the integrity of masks used for lithography is checked. In Figure 1, for example a sensor unit that detects the image of the projected pattern of the reticle 104.1 (for further processing) then replaces the delay of 105.1. The operating wavelength of the mask inspection can then be substantially the same as the wavelength used in the subsequent lithography process. However, the inspection can equally well use operating wavelengths that deviate from any desired wavelength.

Finally, the invention has been described above on the basis of specific exemplary embodiments showing specific combinations of features defined in the patent claims hereafter claimed. It should be expressly pointed out that the subject matter of the present invention is not limited to these combinations of features, but on the contrary, all other combinations of features, such as will be apparent from the patent claims hereinafter, are also subject matter of the present invention.

101: Projection exposure equipment 102:Lighting system 102.1: Radiation source 102.2: Illumination optical unit 102.3: Concentrator 102.4: Radiation source module 102.5:Polarizer 102.6: First facet reflector 102.7: First facet 102.8: Second facet 102.9: Dashed outline 102.10:Transmission optical unit 103:Object equipment 103.1:Object field 103.2:Object plane 103.3:Double reduction mask 103.4: Reduced mask bearing platform 103.5: Mask displacement driver 104:Projection device 104.1: Projection optical unit 104.2: Support structures 105:Image installation 105.1: Image field 105.2:Image plane 105.3:wafer 105.4:Wafer carrying platform 105.5: Wafer displacement driver 106:Control device 107: EUV radiation 107.1: Intermediate focus plane 108:Optical configuration 108.1: First active support unit 108.2: Second active support unit 109: Capture device DI1: First transformation information DI2: Second transformation information LI1: First posture information LI2: Second posture information M1: Second optical element M2: First optical element M3: Second optical element M4: First optical element M5: First optical element M6: First optical element R: reference point

FIG. 1 is a schematic diagram of a preferred embodiment of a projection exposure apparatus according to the present invention, which includes a preferred embodiment of an optical device configuration according to the present invention and can use a method for supporting optical elements according to the present invention. Preferred specific embodiments to perform preferred specific embodiments of the imaging method according to the present invention.

FIG. 2 is a flow chart of a preferred embodiment of an imaging method according to the present invention, which can be performed by the projection exposure apparatus of FIG. 1 using a preferred embodiment of a method for supporting optical elements according to the present invention.

101: Projection exposure equipment

102:Lighting system

102.1: Radiation source

102.2: Illumination optical unit

102.3: Concentrator

102.4: Radiation source module

102.5:Polarizer

102.6: First facet reflector

102.7: First facet

102.8: Second facet

102.9: Dashed outline

102.10:Transmission optical unit

103:Object device

103.1:Object field

103.2:Object plane

103.3: Photomask

103.4: Mask carrier

103.5: Mask displacement driver

104:Projection device

104.1: Projection optical unit

104.2: Support structures

105:Image installation

105.1: Image field

105.2:Image plane

105.3:wafer

105.4:Wafer carrying platform

105.5: Wafer displacement driver

106:Control device

107: EUV radiation

107.1: Intermediate focus plane

108:Optical configuration

108.1: First active support unit

108.2: Second active support unit

109: Capture device

M1: Second optical element

M2: First optical element

M3: Second optical element

M4: First optical element

M5: First optical element

M6: First optical element

R: reference point

Claims (19)

An optical configuration of a lithographic imaging device, particularly using light in the extreme ultraviolet (EUV) range, comprising: a group of optical components; a support structure (140.2); an active support device (108); and a control device (106), in The optical element group includes a plurality of N optical elements (M1 to M6), which are supported on the support structure (104.2) by the active support device (108); The active support device (108) includes one active support unit (108.1, 108.2) for each optical element (M1 to M6) in the optical element group, the active support unit being configured to operate on the control device (106) The optical element can be adjusted to be supported on the support structure (104.2) under the control of The optical element group includes a first sub-group having a plurality of M first optical elements (M2, M4, M5, M6); The optical element group includes a second subgroup having a plurality of K second optical elements (M1, M3); The control device (106) and a first active support unit (108.1) assigned to the respective first optical element (M2, M4, M5, M6) are configured to operate with a maximum control bandwidth in a first control bandwidth range. Adjust the first optical element (M2, M4, M5, M6) with at least one degree of freedom; The control device (106) and a second active support unit (108.1) assigned to the respective second optical element (M1, M3) are configured to operate in at least one degree of freedom with a maximum control bandwidth in a second control bandwidth range. Adjust and/or deform the second optical element (M1, M3), It is characterized by The first control bandwidth range is lower than the second control bandwidth range and is separated from the second control bandwidth range by an interval, in The interval is at least 50% of one of the upper limits of the first control bandwidth range, preferably at least 100%, and further preferably at least 125%, and/or The interval is at least 40 Hz to 80 Hz, preferably 50 Hz to 175 Hz, further preferably 75 Hz to 125 Hz. The optical configuration as described in claim 1, wherein The first control bandwidth ranges from 50 Hz to 180 Hz, preferably from 75 Hz to 160 Hz, and further preferably from 90 Hz to 120 Hz; and/or The second control bandwidth ranges from 180 Hz to 260 Hz, preferably from 200 Hz to 250 Hz, and further preferably from 220 Hz to 250 Hz. An optical configuration as claimed in claim 1 or 2, wherein The control device (106) is connected to a capture device (109), in The capturing device (109) is configured to capture first attitude information for at least the first optical elements (M2, M4, M5, M6), the attitude information representing the first optical elements (M2, M4, M5, M6 ) their respective position and/or orientation relative to a reference point (R) in at least one degree of freedom; and/or The capturing device (109) is configured to capture first deformation information for at least the first optical elements (M2, M4, M5, M6), the deformation information representing the first optical elements (M2, M4, M5, M6 ) respective deformation in at least one degree of freedom; and/or The capture device (109) is configured to capture imaging aberration information, which represents the imaging aberration of the imaging device (101), in The control device (106) is configured to drive the at least one second active support unit (108.2) based on the first posture information and/or based on the first deformation information and/or based on imaging aberration information. The optical configuration as described in claim 3, wherein The optical element group causes imaging aberrations of the imaging device (101) during operation; and The control device (106) is configured to drive the at least one second active support unit alone or in combination with at least one additional component (103, 105) of the imaging device (101) in an imaging aberration correction step (110.5) (108.2), so that the imaging aberration can be at least reduced, and in particular, the imaging aberration can be basically eliminated, Among them in particular The at least one second active support unit (108.2) has an active deformation unit driven by the control device (106) with the maximum control bandwidth for the second optical element (M1, M3) in at least one free Set a deformation of the specified second optical element (M1, M3) under a certain degree; and/or The at least one second active support unit (108.2) has an active attitude control unit driven by the control device (106) for the maximum control bandwidth of the second optical element (M1, M3) Set a specified position and/or orientation of the second optical element (M1, M3) in at least one degree of freedom; and/or The at least one additional component (103, 105) of the imaging device is an image device (105) or an object device (103) of the imaging device (101). The optical configuration as described in claim 4, wherein In the imaging aberration correction step (110.5), the control device (106) uses a stored correction model to drive the at least one second active support unit (108.2) and selectively drive the at least one element of the imaging device (101). an additional component (103, 105) to at least reduce, in particular substantially eliminate, the imaging aberration, in The correction model provides control information for driving the at least one second active support unit based on the first attitude information (108.2); and/or The correction model provides control information for driving the at least one second active support unit (108.2) based on the first deformation information; and/or The correction model provides control information for driving the at least one second active support unit (108.2) based on the imaging aberration information; which selectively The correction model provides a first method for driving the at least one additional component (103, 105) of the imaging device (101) based on the first posture information and/or the first deformation information and/or the imaging aberration information. Control information of three active support units (103.5, 105.5). The optical configuration as described in claim 5, wherein In a model correction step (110.9), the control device (106) is configured to correct the correction model based on the imaging aberration information of the previous imaging aberration correction step (110.5), in particular based on the immediately previous imaging aberration. The imaging aberration information of the correction step (110.5); and The control device (106) is configured to use the correction model corrected in the model correction step (110.9) in the imaging aberration correction step (110.5). The optical configuration according to any one of claims 3 to 6, wherein The capturing device (109) is configured to capture second attitude information for the at least one second optical element (M1, M3), the attitude information indicating that the at least one second optical element (M1, M3) is in at least one A position and/or orientation relative to a reference point (R) in degrees of freedom; and/or The capturing device (109) is configured to capture second deformation information for the at least one second optical element (M1, M3), the deformation information representing the at least one second optical element (M1, M3) in at least one A deformation under degrees of freedom, in The control device (106) is configured to drive the at least one second active support unit (108.2) based on the second posture information and/or based on the second deformation information. Optical configuration as described in claims 5 and 7, wherein The calibration model provides the control information for driving the at least one second active support unit (108.2) based on the second position information; and/or The correction model provides control information for driving the at least one second active support unit (108.2) based on the second deformation information, Among them in particular In a model correction step (110.9), the control device (106) is configured to correct the correction model based on the at least one imaging aberration information item emerging from a previous imaging aberration correction step (110.5), in particular based on direct The imaging aberration information appearing in the previous imaging aberration correction step (110.5), and the control device (106) is configured to use in the imaging aberration correction step (110.5) in the model correction step (110.9) The calibrated model. The optical arrangement according to any one of claims 1 to 8, wherein The plural number N is equal to 2 to 12, preferably equal to 4 to 10, more preferably equal to 6 to 8; and/or The plural number M is equal to 2 to 10, preferably equal to 3 to 8, more preferably equal to 4 to 6; and/or The complex number K is equal to 1 to 12, preferably equal to 4 to 10, more preferably equal to 6 to 8; and/or The first subgroup includes the largest optical element (M6) in the optical element group and/or the heaviest optical element (M6) in the optical element group; and/or The first subgroup includes the second largest optical element (M2) of the optical element group and/or the second heaviest optical element (M2) of the optical element group; and/or The second subgroup includes the smallest optical element (M3) in the optical element group and/or the lightest optical element (M3) in the optical element group; and/or The second subgroup includes the second smallest optical element (M1) in the optical element group and/or the second lightest optical element (M1) in the optical element group. An optical imaging device, especially a photolithography optical imaging device, which includes: A lighting device (102) having a first optical element group (102.2); An object device (103) for receiving an object (103.3); a projection device (104) having a second optical element group (104.1); and An image device (105), wherein The lighting device (102) is configured to illuminate the object (103.3); and the projection device (104) is configured to project an image representation of the object (103.3) onto the image device (105), It is characterized by The projection device (104) includes at least one optical arrangement (108, 208) according to any one of claims 1 to 9. A method for supporting a group of optical elements on a support structure (104.2) of a lithographic imaging device, in particular using light in the extreme ultraviolet (EUV) range, wherein The optical element group includes a plurality of N optical elements (M1 to M6) supported on the support structure (104.2) by the active support device (108), wherein the optical element group includes a plurality of M optical elements (M1 to M6). a first subgroup of optical elements (M2, M4, M5, M6), the optical element group including a second subgroup of a plurality of K second optical elements (M1, M3); Each optical element in the optical element group can be adjusted to be supported on the support structure by an active support unit (104.2); Each of the first optical elements (M2, M4, M5, M6) is adjusted in at least one degree of freedom by a designated first active support unit (108.1) with a maximum control bandwidth in a first control bandwidth range, Each of the second optical elements (M1, M3) is adjusted and/or deformed in at least one degree of freedom by a designated second active support unit (108.2) with a maximum control bandwidth in a second control bandwidth range, It is characterized by The first control bandwidth range is lower than the second control bandwidth range and is separated from the second control bandwidth range by an interval, in The interval is at least 50% of the upper limit of the first control bandwidth range, preferably at least 100%, and further preferably at least 125%; and/or The interval is at least 40 Hz to 80 Hz, preferably 50 Hz to 175 Hz, further preferably 75 Hz to 125 Hz. A method as described in claim 11, wherein The first control bandwidth range is 50 Hz to 180 Hz, preferably 75 Hz to 160 Hz, and further preferably 90 Hz to 120 Hz; and/or The second control bandwidth range is 180 Hz to 260 Hz, preferably 200 Hz to 250 Hz, and further preferably 220 Hz to 250 Hz. A method as described in claim 11 or 12, wherein Acquire first attitude information for at least the first optical elements (M2, M4, M5, M6), the first attitude information indicates that the first optical element (M2, M4, M5, M6) is in at least one degree of freedom their respective position and/or orientation relative to a reference point (R); and/or Acquire first deformation information for at least the first optical elements (M2, M4, M5, M6), the first deformation information represents the first optical element (M2, M4, M5, M6) under at least one degree of freedom their respective deformations; and/or Retrieve imaging aberration information representing an imaging aberration of the imaging device (101); in The at least one second active support unit is driven based on the first posture information and/or based on the first deformation information and/or based on imaging aberration information (108.2). A method as described in claim 13, wherein The optical element group causes imaging aberrations of the imaging device (101) during operation; and In an imaging aberration correction step (110.5), the at least one second active support unit (108.2) is driven alone or in combination with at least one additional component (103, 105) of the imaging device (101), so that at least In particular, imaging aberrations are basically eliminated, In particular The at least one second active support unit (108.2) has an active deformation unit that sets the designated second optical element in at least one degree of freedom with the maximum control bandwidth for the second optical element (M1, M3) A deformation of (M1, M3); and/or The at least one second active support unit (108.2) has an active attitude control unit that sets the specified second optical element in at least one degree of freedom with the maximum control bandwidth for the second optical element (M1, M3). a position and/or orientation of components (M1, M3); and/or The at least one additional component (103, 105) of the imaging device is an image device (105) or an object device (103) of the imaging device (101). A method as described in claim 14, wherein A stored correction model is used in the imaging aberration correction step (110.5) to drive the at least one second active support unit (108.2) and selectively drive the at least one additional component (103, 105) of the imaging device to At least reduce, especially basically eliminate, the imaging aberration, in The correction model provides control information for driving the at least one second active support unit based on the first attitude information (108.2); and/or The correction model provides control information for driving the at least one second active support unit based on the first deformation information (108.2); and/or The correction model provides control information (108.2) for driving the at least one second active support unit based on the imaging aberration information, which selectively The correction model provides a first method for driving the at least one additional component (103, 105) of the imaging device (101) based on the first posture information and/or the first deformation information and/or the imaging aberration information. Control information of three active support units (103.5, 105.5). A method as described in claim 15, wherein In a model correction step (110.9), the correction model is corrected based on at least one imaging aberration information emerging from the previous imaging aberration correction step (110.5), in particular based on the direct previous imaging aberration correction step (110.5). 110.5) The imaging aberration information that occurs; and In the imaging aberration correction step (110.5), the correction model corrected in the most recent previous model correction step (110.9) is used. A method as described in any one of claims 13 to 16, wherein Acquire second attitude information for the at least one second optical element (M1, M3), the attitude information representing the second optical element (M1, M3) relative to the reference point (R) in at least one degree of freedom. a position and/or orientation; and/or Retrieving second deformation information for the at least second optical element (M1, M3), the deformation information representing a deformation of the second optical element (M1, M3) in at least one degree of freedom, in The at least one second active support unit is driven based on the second posture information and/or based on the second deformation information (108.2). Methods as described in requests 15 and 17, wherein The correction model provides the control information for driving the at least one second active support unit based on the second position information (108.2); and/or The correction model provides control information (108.2) for driving the at least one second active support unit based on the second deformation information, Among them in particular In a model correction step (110.9), the correction model is corrected based on the imaging aberration information item from the previous imaging aberration correction step (110.5), in particular based on the direct previous imaging aberration correction step (110.5). ) of the imaging aberration information, and in the imaging aberration correction step (110.5), use the correction model corrected in the model correction step (110.9). An optical imaging method, especially a photolithography optical imaging method, wherein a lighting device (102) having a first optical element group (102.2) and illuminating an object (103.3); and a projection device (104) having a second optical element group (104.1) and projecting an image representation of the object (103.3) onto an image device (105), It is characterized by At least the optical elements (M1 to M6) of the second optical element group of the projection device (104) are supported by a method as described in any one of claims 11 to 18.

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