DE102007055097A1 - Scattered radiation measuring method for use in optical system, involves passing radiation from radiation source through mask, and measuring intensity of radiation passed through another mask with locally resolving detector - Google Patents

Abstract

The method involves passing radiation from a radiation source (16) through a mask (22). The radiation from the mask is passed through an optical system, and the radiation from the optical system is passed through another mask (24). An intensity of the radiation passed through the latter mask is measured with a locally resolving detector (26), and a locally distributed intensity is evaluated into a pupil resolved measurement result of scattered radiation, where the masks are configured with different transmission structures. An independent claim is also included for a device for measuring a scattered radiation at an optical system.

Description

The The invention relates to a method for scattered radiation measurement on a optical system, in particular on a projection optics of an exposure system for the Microlithography. Furthermore, the invention relates to a device for scattered radiation measurement on an optical system, in particular a Projection optics of an exposure system for microlithography, a Exposure system for Microlithography with such a device and a Wafer stage for microlithography with such an exposure system. Finally, the concerns Invention also the use of a known device on a Exposure system for microlithography for scattered radiation measurement.

The Stray radiation measurement is present in systems for microlithography very important measurement method to qualify the associated optical system to be able to. So it is for the qualification of an optical system for microlithography, such as For example, a lithography lens, not enough, to measure only the low aberrations or aberrations, rather, it is for an accurate prediction of the lithographic performance of the optical Systems also the knowledge of its scattered radiation component for different ranges the guided through the optical system radiation, in particular Light radiation, of vital importance.

Of the Scattered radiation component for Different scatter ranges can be found in known scattered radiation measurements be determined on optical systems by the so-called Kirk test, in which a photoresist layer is irradiated by two inverse masks and the result subsequently subjectively inspected for scattered radiation becomes. The problem is that there are several irradiations at different energies, a corresponding development and requires a manual inspection. To overcome some of these disadvantages An improved test was developed, but with an additional test Diode sensor must be present in the wafer stage as well as a special Measuring reticle is necessary.

It An object of the present invention is a method and a To provide apparatus for scattered radiation measurement, in which the overcome the above disadvantages and overall a particularly meaningful and at the same time inexpensive scattered radiation measurement possible are.

The Task is according to the invention with a method for scattered radiation measurement according to claim 1, a method for scattered radiation measurement according to claim 4, a method for scattered radiation measurement according to claim 11, a device for scattered radiation measurement according to claim 12, a device for scattered radiation measurement according to claim 15, a device for scattered radiation measurement according to claim 21, a device for scattered radiation measurement according to claim 24, an exposure system according to claim 25, a wafer stage according to claim 26 and a use of a device for wavefront detection according to claim 27 solved. Advantageous developments of the invention are described in the dependent claims.

According to the invention is a method for scattered radiation measurement on an optical System, in particular an exposure system for microlithography, with following steps: emitting radiation with a Radiation source, passing the radiation from the radiation source a first mask with local varying transmission, passing the radiation from the first mask the optical system, directing the radiation from the optical system through a second mask with locally varying transmission, measuring the intensity of the through the second mask entered radiation with a spatially resolving detector, and evaluation the determined with the detector locally distributed intensity to one pupil-resolved Scattered radiation measurement.

Further is a method of the invention Stray radiation measurement on an optical system of an exposure system for the Microlithography created by the following steps: emitting radiation with a radiation source, directing the radiation from the radiation source through a first mask with locally varying transmission, conduction the radiation from the first mask through the optical system, conducting the radiation from the optical system through a second mask with locally varying Transmission, measuring the intensity of the second mask radiation with a spatially resolving detector, wherein the second mask is moved relative to the first mask, and evaluate the determined with the detector locally distributed intensity to one Scattered radiation measurement.

According to the invention is also a method for scattered radiation measurement on an optical system, especially an exposure system for microlithography, created, in which a pupil dissolves Stray radiation measurement takes place.

Also according to the invention, a device for scattered radiation measurement on an optical system, in particular an exposure system for microlithography, created with a radiation source for emitting radiation, a first mask with locally varying transmission for passing the radiation from the beam source and further through the optical system, a second mask with locally varying transmission for passing the radiation from the optical system, a spatially resolving detector for measuring the intensity of the radiation passed through the second mask and an evaluation device for evaluating the determined with the detector locally distributed Intensity to a pupil-resolved scattered radiation result.

Further is the task according to the invention with a Device for scattered radiation measurement on an optical system, in particular, an exposure system for microlithography, solved, with a radiation source for emitting radiation, a first Mask with local varying transmission for passing the radiation from the Radiation source and further through the optical system, a second Mask with local varying transmission for passing the radiation from the optical System, a spatially resolving Detector for measuring the intensity the radiation passed through the second mask, a movement device for moving the second mask relative to the first mask and a Evaluation device for evaluating the locally distributed with the detector determined intensity to a scattered radiation result.

Furthermore is the object according to the invention with a device for scattered radiation measurement on an optical System, in particular an exposure system for microlithography, solved with a radiation source for emitting radiation, a first Mask with local varying transmission for passing the radiation from the Radiation source and further through the optical system, a second Mask with local varying transmission for passing the radiation from the optical system and a spatially resolving detector for measuring the intensity of radiation passed through the second mask, at which the measurement plane of the spatially resolving Detector in the radiation direction behind the image plane of the optical Systems is arranged.

Also is according to the invention a device for scattered radiation measurement on an optical system, especially an exposure system for microlithography, created, in which an evaluation device is provided, adapted to it is, a pupil-resolved Perform scattered radiation measurement.

Further is an exposure system according to the invention for the Microlithography with such a device according to the invention and a wafer stage with such a device according to the invention created.

According to the invention is finally to the solution the above object also the use of a device for wavefront detection on an optical system of an exposure apparatus for microlithography for scattered radiation measurement on the optical system of the exposure system proposed.

Of the solution according to the invention the realization that it is problematic in known solutions is that no assignment of detected stray radiation to a Position occurs within the pupil of the optical system, so the scattered radiation situation not with regard to a particular Angle determined on a wafer irradiated with the optical system can be. According to the invention was further recognized that an assignment of scattered radiation to a Position within the pupil of an optical system or pupil-resolved evaluation the measured stray radiation is an important parameter for the qualification of a optical system, in particular a scanner for microlithography. The invention therefore provides in particular that this size means a pupil-resolved Stray radiation measurement is determined. This measurement is inventively particular done by that electromagnetic radiation from a radiation source through two masks, a first, so-called windscreen mask on the optical system and a second, so-called Lee mask on the optical system, passed becomes. Here, by passing the radiation through the masks in addition to a pure transmission through a mask layer also understood the reflection of radiation on a reflection mask should be, as is customary in particular for EUV radiation (extreme ultraviolet light). The masks each have a local varying transmission. Hereinafter, the intensity of the present invention the second mask occurred radiation with a spatially resolving detector determined and determined in a solution according to the invention thereby determined locally distributed intensity to a pupil-resolved Scattered radiation measurement evaluated.

In this way, it can be distinguished according to the invention with regard to the scattered radiation situation, for example between near-scattered scattered radiation and off-axis scattered radiation. While near-axis scattered rays result from multiple reflection on surfaces of the optical system, off-axis scattered rays generally result from individual beam expansions. Not only is a pupil-resolved scattered radiation measurement carried out using the method and the associated device according to the invention, but it is also possible to deduce the quality of the optical system below. Furthermore, causes of lack of quality may be indicated or appropriate countermeasures or adjustments, for example in the form of appropriately adapted production masks, can be initiated.

Prefers the measurement according to the invention takes place the intensity the radiation that has passed through the second mask in several areas with local varying transmission, which in the far field or in the image plane Illuminate the same pupil. The advantage lies in one significantly higher intensity on the associated spatially resolving Detector, such as a CCD chip, and associated a higher one Measurement accuracy and a lower susceptibility to local Mask errors. Furthermore, it is preferred between the radiation source and the first mask is arranged a lens.

It is according to the invention also provided that during the measurement of the radiation having passed through the second mask a spatially resolving Detector, the second mask is moved relative to the first mask. With such a relative offset between the first and the second mask during the measurement results in a wave-shaped scattered radiation intensity curve, from the for the different places of the pupil corresponding to the minimum be determined and in this way a pupil-resolved scattered radiation measurement can be provided.

at an advantageous development of the procedure according to the invention is at least one mask with a plurality of periodically arranged Regions of varying transmission designed. The case in particular as openings designed areas or areas with locally varying transmission inside the mask make a high difference in transmission ready and enable it size Measuring ranges with correspondingly high measuring accuracy. The majority of openings allows a widely distributed measurement to achieve the widest possible pupil-resolved scattered radiation measurement to obtain. The periodicity the openings leaves comparisons or conclusions between the measurements at the individual openings to, so again a higher Accuracy and measurements less than local mask errors susceptible are.

Prefers Further, the second mask is inverse with the first mask Transmission structure designed. Such a mask combination allows a particularly simple scattered radiation measurement, because the information about the Stray radiation can be achieved solely by covering the image of the first mask be obtained by the image of the second mask. Furthermore, a Calibration of the measurement over a dark picture possible.

in the With regard to the movement according to the invention the second mask relative to the first mask, thereby the minimum the scattered radiation intensity very precise It is advantageous to determine the relative movement in a first Direction and a second direction, which lead to the first direction is substantially perpendicular. It is particularly preferred that second mask moves because their movement in view of the current state The technology is easier on a wafer stage. With the spatially resolving detector used according to the invention In this case, a two-dimensional intensity information is measured and according to the scattered radiation situation at the examined optical System inferred. The relative movement of the two masks is particularly preferably similar to the phase shifting for a wavefront sensor, as it can be present in known wafer stages. With a Such wavefront sensor is the wavefront in the measurement plane from a big one Number of partial beams reconstructed. According to the invention can such sensor for the scattered radiation measurement can be exploited by using the spatially resolving detector the wavefront sensor also extracts scattered radiation information becomes.

The Scattered radiation information and in particular the pupil-resolved scattered radiation result is obtained by, as explained above, in particular the principle inverse Masks are brought in such a way that a direct fluoroscopy no longer occurs and only scattered radiation through the second Mask can pass through. By means of a movement of the masks relative to similar to each other The phase shifting of existing wavefront sensors can be the minimum the scattered radiation intensity also pupil-resolved, i.e. assigned to the individual positions within the pupil or a certain angle on an associated wafer.

Especially Preferably, at least one mask is used, which is a periodic structure locally varying transmission, and moving the second Mask relative to the first mask is done this moving over several Periods of said structure. The procedure leads to a particularly precise and of local mask errors largely independent measurement.

Furthermore, according to the invention, a procedure is preferred in which both the first mask and the second mask have a periodic structure of locally varying transmission and both periodic structures have the same period. With such masks, with respect to the measured scattered radiation intensity, a sinusoidal signal should be obtained, of which deviations be especially easy to recognize.

Further it is inventively preferred with a first and a second mask to work, which also both a periodic structure locally have varying transmission, both periodic structures but different duty cycles to have. Such masks lead to a distorted sinusoidal signal, the shape of the waveform from the duty cycle depending on the two masks is. By means of different duty cycles can then accordingly on the quality of pupil-resolved optical system inferred become.

Especially Preferably, the first and the second mask both have a periodic one Structure locally varying transmission on and the duty cycle of at least one the two masks is greater than one selected. This means that this mask has larger dark areas than transparent ones Has areas. It can be ensured in this way that independent minor deviations in the relative position of the two Masks to each other in the covered state only scattered radiation to contributes measured signal. Which of the two masks has a larger duty cycle, basically plays no role with regard to the results obtained Role.

at another solution the task of the invention is on the above already explained in the basic features device a spatially resolving detector to measure the intensity provided by the second mask radiation, whose Measuring plane in the radiation direction behind the image plane or focal plane of the optical system is arranged. Particularly preferred is at the device of the second mask in the image plane of arranged optical system. With the detector arranged in this way the angular orientation of scattered radiation can be determined which varies locally by the second mask at the individual areas Transmission passes through and it can in this way a pupil-resolved scattered radiation measurement being represented.

As already mentioned above, it is particularly according to the invention preferred, for a scattered radiation measurement on a wafer stage a basically known Device for wavefront detection at the associated exposure system to use. Known wavefront detection devices have in particular devices for arranging the invention used first mask and the second mask used in the invention as well as a spatially resolving Detector according to the invention for the actual Stray radiation measurement is used. Furthermore, known devices allow for wavefront detection a relative movement of two masks to each other. According to the invention with such an existing wavefront sensor scattered radiation information extracted, especially when using EUV radiation (Extreme Ultraviolet radiation) may be crucial because there is a big one there It can make a difference if you have one or two spatially resolved detectors on a wafer stage. As a device for wavefront detection are particular to the invention Interferometer preferred, where basically different types of Interferometers used in the procedure of the invention can be. Such interferometers include a PDI (Point Diffraction Interferometer), an LDI (Line Diffraction Interferometer), an LSI (Lateral Shearing Interferometer), a SLSI (Slit-type Lateral Shearing Interferometer), a CGLSI (Cross-grating Lateral Shearing Interferometer) and a DLSI (Double-grating Lateral Shearing Interferometer).

The doing with the interferometer according to the invention reached scattered radiation measurement is particularly preferably pupil-resolved, whereby, as explained above, in particular between the scattered radiation of near-to-axis rays and the scattered radiation farther away from the axis Radiation can be distinguished. It will be beyond that preferably one or more masks with a plurality of periodically arranged areas of varying transmission, in particular openings used, which preferably have an inverse transmission structure. For improved determination of the minimum of the measured scattered radiation intensity is preferred performed a relative movement of the two masks, this movement advantageous performed in two directions becomes. Particularly advantageous are masks with a periodic structure, wherein the structures preferably equal period and / or different duty cycles exhibit, so that is strictly sinusoidal or distorted sinusoidal signals the scattered radiation intensity result. After all as mentioned above, preferably uses masks in which the duty cycle of at least one of the masks greater than one is.

Of the spatially resolving Detector of the device according to the invention is also advantageous with a point or line measuring Sensor and a movement device for moving the sensor in designed in at least one direction.

following Be exemplary embodiments of inventive method and devices for scattered radiation measurement on an optical System based on the attached schematic drawings closer explained. It shows:

1 a representation of the basic structure of an embodiment of an inventive Apparatus for scattered radiation measurement on an optical system, in the present case an exposure apparatus for microlithography,

2 in each case the plan view of three different embodiments of masks a device according to 1 .

3 a representation of a waveform of the intensity measurement on a device according to 1 with an associated first embodiment of masks,

4 a representation of a waveform of the intensity measurement on a device according to 1 with an associated second embodiment of masks,

5 a highly schematic representation of two signal waveforms of the intensity measurement on a device according to 1 with two associated embodiments of masks,

6 a highly schematic representation of two signal waveforms of the intensity measurement on a device according to 1 with two associated embodiments of masks,

7 a part of the representation according to 1 with the illustration of a first possible type of scattered radiation and

8th a part of the representation according to 1 with the illustration of a second possible type of scattered radiation.

In 1 is an exposure system 10 for microlithography, which illustrates an optical system 12 having in the form of a projection optics. On the optical system 12 is a device 14 intended for the measurement of scattered radiation, which in the optical system 12 arises when this by means of a radiation source 16 in the form of a luminaire for electromagnetic radiation, in particular in the ultraviolet wavelength range.

The device 14 includes a scattered light disk 18 , which in the radiation direction behind the radiation source 16 in front of a reticle 20 and a first mask 22 is arranged. The first mask 22 has areas with locally varying transmission and is located in the direction of radiation in front of the optical system 12 so that the radiation from the radiation source 16 partly on the first mask 22 is held or shadowed and only part of the radiation in the optical system 12 and through it. The radiation is from the optical system 12 Projected onto an image plane, during the actual use of the exposure system 10 a wafer is located. For the case of a scattered radiation measurement at the exposure system 10 , is in the image plane, ie in the direction of radiation behind the optical system 12 , a second mask 24 arranged behind this mask nor a spatially resolving detector 26 in the form of a photoelectric detector, such as a CCD detector.

The masks 22 and 24 as well as the detector 26 are adapted to one another in such a way that a pupil-resolved scattered radiation measurement can take place with them. For this type of scattered radiation measurement is in particular a specially adapted evaluation 28 to the detector 26 connected and it is also a moving device 30 provided by means of the second mask 24 relative to the first mask 22 and relative to the optical system 12 can be moved in the image plane in a first direction and in particular in a second direction perpendicular to the first direction.

The first mask 22 and the second mask 24 as well as the movement device 30 are part of an exposure system 10 provided device for wavefront detection, wherein the evaluation device 28 adapted to, from the signal of the detector 26 to extract a scattered radiation information. This is particularly advantageous because no separate sensor has to be provided for such a scattered radiation measurement. Especially with exposure systems with EUV exposure, it can be very important whether one or two sensors must be accommodated on the wafer stage. As a device for wavefront detection, in particular interferometers are used, which have two masks or gratings, which in the present case the first mask 22 and the second mask 24 form and in which also the second mask for so-called phase shifting can be moved. The present embodiment then forms an extension of such an interferometer measurement technique towards additional scattered radiation information from the two-dimensional intensity information measured with the detector. The scattering payment information can be prepared and evaluated in such a way that it is pupil-resolved, that is to say the determined scattered radiation reaches a position within the pupil of the optical system 12 or a certain angle on the wafer can be assigned.

2 shows various embodiments of first and second masks, which are used for the scattered radiation measurement according to the invention. A first mask 32 has a central pad 34 on which a shadowing of radiation in the middle of the mask 32 generated. An associated second mask 36 has a central opening corresponding to the pad 34 on, so it at a superimposition of the two masks 32 and 36 should come to a Vollabschattung. The full shading can be circumvented only by scattered radiation or stray light, which in the optical system 12 arises. The intensity and the position of this scattered radiation is determined according to the invention by the second mask 36 relative to the first mask 32 moves while holding the pad 34 in coincidence with the associated opening in the second mask 36 is brought. The result is a sinusoidal waveform, which with the detector 26 reproduced intensity curve reproduces.

The minimum of this trace represents the intensity of scattered radiation on the measured pad 34 The flanks of the trace allow a conclusion on the type and position of the scattered radiation within the pupil. In other words, you get a minimum of the signal curve if and only if the aerial image of the first mask 32 (which could also be referred to as a reticle grid) centered relative to the second mask 36 (which could also be called a wafer grid). The signal strength at this minimum can be evaluated and one obtains information about the height and from the location of the measurement also about the type of scattered radiation. For configurations with a singular pad 34 One obtains a scattered integral from a to infinity, where a is half the difference of the edge length of the transparent area of the second mask 36 and the edge length of the dark area of the first mask 32 is.

In 2 is also a first mask 38 and an associated second mask 40 illustrates where a total of four pads 34 are each provided in the corner regions of the otherwise square masks. The pads 34 are arranged so that they are in the far field on the measuring plane of the detector 26 Illuminate the same pupil. The advantage lies in a much higher intensity at the detector 26 and associated higher accuracy and less susceptibility to local mask errors.

At another in 2 right first mask 42 are the areas of locally varying transmission by means of stripes 44 designed and an associated second mask 46 is designed with correspondingly designed strips with inverse transmission structure. The pads 34 were replaced by a periodic structure, eg a line grid. This embodiment is close to a wavefront interferometer.

Particularly advantageous is done with these masks 42 and 46 the movement by means of the movement device 30 over several phases of the periodic structure, whereby the measurement accuracy can be further improved. With such periodic structures, a phase shift curve is obtained as the signal curve, again the minimum of this measurement curve containing the scattered radiation information. In the case of the measurement according to the invention, it is therefore less dependent on the phase of the signal, as is the case with devices for wavefront detection, but rather on the one or more minima of the measured intensity signal profiles.

3 and 4 show signal curves 48 and 50 of measurements according to the invention during the displacement of a second mask 46 relative to a first mask 42 , In the case of 3 are the masks 46 and 42 around masks with identical structure. You get with such masks 42 and 46 a sinusoidal signal. 4 shows the waveform 50 with a combination of a first mask 42 with a second mask 46 in which the masks have the same periods but different duty cycles. The different duty cycles lead to a "distorted" sinusoidal signal.

In the 5 and 6 In each case the intensity of scattered radiation (Y-axis) is shown over the range of the scattered radiation (X-axis). The scattered radiation at a location of the pupil results in the optical system 12 along a scattered radiation intensity course decreasing over the range 52 , This is shown in the diagrams according to the 5 and 6 each strongly schematized the waveform of the intensity measurement with a detector 26 shown. It depends on the type of masks used 42 and 46 different signal curves. A first waveform 54 results for masks that have the same periods and duty cycles. A second waveform 56 is created for masks that have the same periods and different duty cycles. The waveforms are also periodic due to the periodic structures of the masks used, with the zeros resulting at multiples of the period. The areas between the zeros are trapezoidal and the shape of the trapezoid depends on the duty cycles of the masks used. It is advisable to choose the duty cycle of one of the masks greater than one, ie the mask has more darker areas than transparent ones. It can be ensured in this way that regardless of the relative position of the masks to each other only scattered radiation contributes to a signal.

6 shows highly schematic signal curves 58 and 60 in which the first mask 42 each having a different duty cycle than that of 5 , It turns out that the scattered radiation intensity course 52 corresponding to longer minima ranges of the intensity gradients 58 respectively. 60 leads to evaluable measurement results.

The 5 and 6 further illustrate how with the individual minima measurements on the waveforms 54 to 60 a "development" of the scattered radiation integrals is possible, so that from these a range-resolved information on the scattered radiation or the scattered light can be extracted. The measured intensities at the individual minima of the signal curves 54 to 60 Namely, in comparison to a basically expected scattered radiation intensity profile (for example, the scattered radiation intensity profile 52 ) and it can then from a determined deviation corresponding to the real existing scattered radiation situation on the optical system 12 be inferred.

Due to the strong drop in the scattered radiation intensity profile 52 to higher ranges of scattered radiation, the periodicity of the detected region can play only a minor role, ie the signal strength is dominated by ranges of scattered radiation of less than one period. In order to avoid such problems, according to the invention, in particular in the case of a scattered radiation measurement, a displacement of different combinations of masks 42 and 46 performed relative to each other. This shift can be carried out sequentially, or else the different masks are arranged side by side or parallel, so that signals of different mask combinations would be obtained at different pupils (so-called Rois). 5 illustrates a highly schematic two waveforms 54 and 56 , where in the waveform 54 the masks 42 and 46 have the same periods and the same duty cycle and in the waveform 56 the masks 42 and 46 have the same periods and different duty cycles. 6 shows a very schematic two waveforms 58 and 60 in which the mask 42 each in comparison to 5 has a changed period and a changed duty cycle.

In the evaluation of the detected during the shift waveforms 54 to 60 is for the individual local areas of the detector 26 and in particular determines a signal minimum separately for each of its pixels. This signal minimum then gives a pupil-resolved scattered radiation measurement, which can optionally be calibrated via a dark image. Furthermore, the integration of the scattered radiation information can be used to determine the intensity over the entire pupil, it also being possible to weight individual pupil areas as required.

In the 7 and 8th becomes the invention possible distinction between different types of scattered radiation on the optical system 12 illustrated. 7 shows the situation with scattered radiation 62 which relate to the axis of the optical system 12 only for very close-to-axis rays due to multiple reflection. This near-axis scattered radiation 62 arrives at the mask 46 by a transparent area, which in the present case is more than one period away from the area which shadows the actual radiation. According to the situation 8th arises stray radiation 64 on the edge of the pupil by a fanning out. This leads to the off-axis scattered radiation 64 passes through those transparent areas which are directly adjacent to the area shading the actual radiation. The distinction thus made between different types of scattered radiation 62 respectively. 64 was not possible with previously known methods.

10

exposure system

12

optical system

14

contraption for scattered radiation measurement

16

radiation source

18

diffuser

20

reticle

22

first mask

24

second mask

26

detector

28

evaluation

30

mover

32

first mask

34

pad

36

second mask

38

first mask

40

second mask

42

first mask

44

strip

46

second mask

48

waveform with equal periods and equal duty cycles

50

waveform with equal periods and different duty cycles

52

Scattered radiation intensity profile

54

strongly schematic waveform with equal periods and same duty cycles

56

strongly schematized waveform with equal periods and different duty cycles

58

strongly schematized waveform with changed period at the first mask

60

strongly schematized waveform with changed period at the first mask

62

near the axis scattered radiation

64

off-axis scattered radiation

Claims (36)

Method for scattered radiation measurement on an optical system ( 12 ) comprising the steps of: emitting radiation with a radiation source ( 16 ), Directing the radiation from the radiation source ( 16 through a first mask with locally varying transmission, directing the radiation from the first mask ( 22 ; 32 ; 38 ; 42 ) through the optical system ( 12 ), Direct the radiation from the optical system ( 12 ) through a second mask ( 24 ; 36 ; 40 ; 46 ) with locally varying transmission, measuring the intensity of the through the second mask ( 24 ; 36 ; 40 ; 46 ) radiation with a spatially resolving detector ( 26 ), and evaluating the with the detector ( 26 ) determined locally distributed intensity to a pupil-resolved scattered radiation result. Method according to Claim 1, in which at least one of the masks ( 22 ; 24 ; 32 ; 36 ; 38 ; 40 ; 42 ; 46 ) having a plurality of periodically arranged regions ( 44 ) varying transmission is designed. Method according to Claim 1 or 2, in which the second mask ( 24 ; 36 ; 40 ; 46 ) with a first mask ( 22 ; 32 ; 38 ; 42 ) inverse transmission structure is designed. Method for scattered radiation measurement on an optical system ( 12 ), in particular according to one of claims 1 to 3, with the steps: emitting radiation with a radiation source ( 16 ), Directing the radiation from the radiation source ( 16 ) through a first mask ( 22 ; 32 ; 38 ; 42 ) with locally varying transmission, directing the radiation from the first mask ( 22 ; 32 ; 38 ; 42 ) through the optical system ( 12 ), Direct the radiation from the optical system ( 12 ) through a second mask ( 24 ; 36 ; 40 ; 46 ) with locally varying transmission, measuring the intensity of the through the second mask ( 24 ; 36 ; 40 ; 46 ) radiation with a spatially resolving detector ( 26 ), the second mask ( 24 ; 36 ; 40 ; 46 ) relative to the first mask ( 22 ; 32 ; 38 ; 42 ) and evaluating with the detector ( 26 ) determined locally distributed intensity to a scattered radiation result. Method according to Claim 4, in which, when the second mask is moved ( 24 ; 36 ; 40 ; 46 ) relative to the first mask ( 22 ; 32 ; 38 ; 42 ) the movement is in a first direction and in a second direction, which is substantially perpendicular to the first direction. Method according to Claim 4 or 5, in which at least one mask ( 22 ; 24 ; 32 ; 36 ; 38 ; 40 ; 42 ; 46 ) a periodic structure ( 44 ) has locally varying transmission and the movement over several periods of this structure ( 44 ) he follows. The method of claim 6, wherein the first and second masks ( 24 ; 36 ; 40 ; 46 ) a periodic structure ( 44 ) locally varying transmission and both periodic structures ( 44 ) have the same period. Method according to Claim 6 or 7, in which the first and the second mask ( 24 ; 36 ; 40 ; 46 ) a periodic structure ( 44 ) locally varying transmission and both periodic structures ( 44 ) have different duty cycles. Method according to one of claims 6 to 8, wherein the first and the second mask ( 24 ; 36 ; 40 ; 46 ) a periodic structure ( 44 ) have locally varying transmission and the duty cycle of at least one of the masks ( 22 ; 24 ; 32 ; 36 ; 38 ; 40 ; 42 ; 46 ) is greater than one. Method according to one of Claims 1 to 9, in which the steps on an optical system ( 12 ) of an exposure system for microlithography. Method for scattered radiation measurement on an optical system ( 12 ), in particular according to one of claims 1 to 10, in which a pupil-resolved scattered radiation measurement is carried out. Device for scattered radiation measurement on an optical system ( 12 ) with a radiation source ( 16 ) for emitting radiation, a first mask ( 22 ; 32 ; 38 ; 42 ) with locally varying transmission for passing the radiation from the radiation source ( 16 ) and further through the optical system ( 12 ), a second mask ( 24 ; 36 ; 40 ; 46 ) with locally varying transmission for passing the radiation from the optical system ( 12 ), a spatially resolving detector ( 26 ) for measuring the intensity of the second mask ( 24 ; 36 ; 40 ; 46 ) radiation and an evaluation device ( 28 ) for evaluating the with the detector ( 26 ) determined locally distributed intensity to a pupil-resolved scattered radiation result. Apparatus according to claim 12, wherein at least one of the masks is provided with a plurality of periodically arranged regions (Fig. 44 ) varying transmission is designed. Device according to Claim 12 or 13, in which the second mask ( 24 ; 36 ; 40 ; 46 ) with a first mask ( 22 ; 32 ; 38 ; 42 ) inverse transmission structure is designed. Device for scattered radiation measurement on an optical system ( 12 ), in particular after egg Nem of claims 12 to 14, with a radiation source ( 16 ) for emitting radiation, a first mask ( 22 ; 32 ; 38 ; 42 ) with locally varying transmission for passing the radiation from the radiation source ( 16 ) and further through the optical system ( 12 ), a second mask ( 24 ; 36 ; 40 ; 46 ) with locally varying transmission for passing the radiation from the optical system ( 12 ), a spatially resolving detector ( 26 ) for measuring the intensity of the second mask ( 24 ; 36 ; 40 ; 46 ) radiation, a movement device ( 30 ) for moving the second mask ( 24 ; 36 ; 40 ; 46 ) relative to the first mask ( 22 ; 32 ; 38 ; 42 ) and an evaluation device ( 28 ) for evaluating the with the detector ( 26 ) determined locally distributed intensity to a scattered radiation result. Apparatus according to claim 15, wherein the moving means for moving the second mask ( 24 ; 36 ; 40 ; 46 ) relative to the first mask ( 22 ; 32 ; 38 ; 42 ) is adapted to perform the movement in a first direction and in a second direction, which is substantially perpendicular to the first direction. Device according to Claim 15 or 16, in which at least one mask has a periodic structure ( 44 ) has locally varying transmission and the movement device ( 30 ) is set up, the movement over several periods of this structure ( 44 ). Apparatus according to claim 17, wherein the first and second masks ( 24 ; 36 ; 40 ; 46 ) a periodic structure ( 44 ) locally varying transmission and both periodic structures ( 44 ) have the same period. Apparatus according to claim 17 or 18, wherein the first and second masks ( 24 ; 36 ; 40 ; 46 ) a periodic structure ( 44 ) locally varying transmission and both periodic structures ( 44 ) have different duty cycles. Device according to one of Claims 17 to 19, in which the first and the second mask ( 24 ; 36 ; 40 ; 46 ) a periodic structure ( 44 ) have locally varying transmission and the duty cycle of at least one of the masks ( 22 ; 24 ; 32 ; 36 ; 38 ; 40 ; 42 ; 46 ) is greater than one. Device for scattered radiation measurement on an optical system ( 12 ), in particular according to one of claims 12 to 20, with a radiation source ( 16 ) for emitting radiation, a first mask ( 22 ; 32 ; 38 ; 42 ) with locally varying transmission for passing the radiation from the radiation source ( 16 ) and further through the optical system ( 12 ), a second mask ( 24 ; 36 ; 40 ; 46 ) with locally varying transmission for passing the radiation from the optical system ( 12 ) and a spatially resolving detector ( 26 ) for measuring the intensity of the second mask ( 24 ; 36 ; 40 ; 46 ) in a measuring plane, in which the measuring plane of the spatially resolving detector ( 26 ) in the radiation direction behind the image plane of the optical system ( 12 ) is arranged. Device according to one of claims 12 to 21, in the spatially resolving detector with a dot or line measuring sensor and a moving means for moving the Sensor is designed in at least one direction. Device according to one of Claims 12 to 22, in which the optical system ( 12 ) is associated with an exposure system for microlithography. Device for scattered radiation measurement on an optical system ( 12 ), in particular according to one of claims 12 to 23, in which an evaluation device ( 28 ) adapted to perform a pupil-resolved scattered radiation measurement. Exposure system ( 10 ) for microlithography with a device according to one of claims 12 to 24. Wafer-stage with a device according to one of claims 12 to 24. Use of a wavefront detection device on an optical system ( 12 ) of an exposure system ( 10 ) for microlithography for scattered radiation measurement on the optical system ( 12 ) of the exposure system ( 10 ). Use according to claim 27, wherein the scattered radiation measurement pupil-resolved he follows. Use according to claim 27 or 28, wherein a first mask ( 22 ; 32 ; 38 ; 42 ) and / or a second mask ( 24 ; 36 ; 40 ; 46 ) with a plurality of periodically arranged regions ( 44 ) varying transmission, in particular in the form of openings, is used. Use according to claim 29, wherein a second mask ( 24 ; 36 ; 40 ; 46 ) with a first mask ( 22 ; 32 ; 38 ; 42 ) inverse transmission structure is used. Use according to any one of claims 27 to 30, wherein a first and a second mask ( 24 ; 36 ; 40 ; 46 ) and in the scattered radiation measurement the second mask ( 24 ; 36 ; 40 ; 46 ) relative to the first mask ( 22 ; 32 ; 38 ; 42 ) is moved. Use according to claim 31, in which the movement of the first mask ( 22 ; 32 ; 38 ; 42 ) relative to the second mask ( 24 ; 36 ; 40 ; 46 ) in a first direction and in a second direction, which is substantially perpendicular to the first direction. Use according to claim 31 or 32, wherein the first and the second mask ( 24 ; 36 ; 40 ; 46 ) a structure ( 44 ) have periodically arranged regions of varying transmission and the movement of the first mask ( 22 ; 32 ; 38 ; 42 ) relative to the second mask ( 24 ; 36 ; 40 ; 46 ) over several periods of the structure ( 44 ) of the periodically arranged regions of varying transmission takes place. Use according to any one of claims 29 to 33, wherein the first and second masks ( 24 ; 36 ; 40 ; 46 ) a structure ( 44 ) have periodically arranged regions of varying transmission and both structures ( 44 ) have the same period. Use according to any one of claims 29 to 34, wherein the first and second masks ( 24 ; 36 ; 40 ; 46 ) a structure ( 44 ) have periodically arranged regions of varying transmission and both structures ( 44 ) have different test conditions. Use according to any one of claims 29 to 35, wherein the first and second masks ( 24 ; 36 ; 40 ; 46 ) a structure ( 44 ) have periodically arranged areas of varying transmission and the test ratio of at least one of the masks ( 22 ; 24 ; 32 ; 36 ; 38 ; 40 ; 42 ; 46 ) is greater than one.