WO2017005912A2

WO2017005912A2 - Method for controlling a beam guiding device, and beam guiding device

Info

Publication number: WO2017005912A2
Application number: PCT/EP2016/066310
Authority: WO
Inventors: Michael Patra
Original assignee: Carl Zeiss Smt Gmbh
Priority date: 2015-07-09
Filing date: 2016-07-08
Publication date: 2017-01-12
Also published as: DE102015212878A1; WO2017005912A3; KR20180028487A; CN107924143B; CN107924143A

Abstract

Illumination radiation (5) emitted by different radiation sources (4_i) can be guided towards different scanners (3_i) by means of a beam guiding device (28).

Description

Method for controlling a beam guiding device and beam guiding device

The present patent application claims the benefit of German Patent Application DE 10 2015 212 878.4, the contents of which are incorporated herein by reference.

The invention relates to a method for controlling a beam guiding device and to a device for guiding a beam path of illumination radiation, in particular of a beam path of illumination radiation in an illumination system of a projection exposure system. Moreover, the invention relates to a beam guiding element. The invention also relates to a lighting system for a projection exposure system with such a beam guiding device. Moreover, the invention relates to a projection exposure system with a corresponding illumination system, a method of operation and a method for the maintenance of such a projection exposure system. Finally, the invention relates to a method for producing a microstructured or nanostructured component and to a component produced by the method.

As a radiation source for a projection exposure system, a free electron laser (FEL) can serve. Free electron lasers are the more cost-effective, the larger they are, relative to their overall emitted radiation power. It is therefore desirable to use a single FEL as a radiation source for a plurality of scanners. However, if this FEL fails, it will affect several scanners.

An EUV lithography system with a free-electron laser and a plurality of scanners is known for example from DE 10 2013 211 830 AI.

It is an object of the invention to provide a method for controlling a beam guiding device and a device by means of which the operation of a projection exposure system, in particular a projection exposure system having at least two radiation sources, in particular in the form of FEL, and a plurality of scanners is improved.

These objects are achieved by a method according to claim 1 or by a beam guiding device according to claim 3. The essence of the invention is to provide, in a method for controlling a beam-guiding device in an operating mode, a periodic change of the assignment of at least one of the inputs of the beam-guiding device to its outputs, the period of this change being adapted to the exposure time of a die. The ratio of the period of change to the exposure time of a die is in particular in the range from 1: 2 to 2: 1, in particular in the range from 0.9 to 1.1. In particular, the period may correspond precisely to the illumination duration of a dies. Preferably, a change of the assignments of one of the inputs of the radiation device to the outputs thereof can be achieved by a rotation of a beam-guiding element. In particular, a uniform rotation of the beam guiding element is provided. As a result, angular acceleration of the beam guiding element can be avoided. According to a further aspect of the invention, the jet device has a further operating mode, in which a constant assignment of the inputs of the beam guiding device to the outputs of the beam guiding device is predetermined.

In particular, it is possible to switch over between the two operating modes manually.

The method is therefore particularly suitable both for operating a plurality of scanners with a single radiation source and for operating the scanner with a plurality of radiation sources. It is particularly possible to switch between the two operating modes in case of failure of a radiation source, for example for maintenance purposes.

Another core of the invention is to provide a device for guiding the beam path of illumination radiation, by means of which the illumination radiation from at least one radiation source, in particular a FEL, can be distributed to different subsets of scanners. The device comprises at least one input and at least two outputs for illumination radiation and at least one beam guidance element which can be displaced between at least two displacement positions, wherein the lighting tion radiation from at least one input in dependence on the displacement position of the beam-guiding element to different of the at least two outputs can be steered.

With such a beam-guiding device, it is possible to supply a plurality of scanners, in particular at least two groups of scanners, with illumination radiation with a single FEL. The scanners are supplied in particular at intervals, in particular sequentially, with illumination radiation. Surprisingly, it was recognized that this is possible without a significant loss of production. According to a further aspect of the invention, the device comprises at least two inputs for illumination radiation and at least two outputs for illumination radiation and at least two beam guidance elements, which are displaceable between at least two displacement positions, wherein the illumination radiation from the first input in dependence of the displacement position of the first beam guiding Element is steerable to different of the at least two outputs, and wherein the illumination radiation from the second input in dependence on the displacement position of the second beam-guiding element to different of the at least two outputs is steerable.

It has been recognized that with such a beam-guiding device it is possible to distribute the illumination radiation of at least two separate radiation sources, in particular two FELs, to different subsets of scanners. In particular, it is possible to supply a plurality of scanners with illumination radiation by means of two FELs, wherein each of the two FELs can also provide illumination radiation in the basic state of the scanner supplied with illumination radiation in the case of a failure of the other of the FELs. In particular, it is possible during a maintenance interval in which one of the FELs is switched off to supply all the scanners of the projection exposure system with illumination radiation by means of the other FEL. Ideally, there will be no loss of production. The production loss in the maintenance interval is in particular at most 25%, in particular at most 20%, in particular at most 15%, in particular at most 10%, in particular at most 5%. The beam guiding device is in particular designed in such a way that the illumination radiation from the FEL is guided to different outputs, that is to different scanners, as a function of the displacement positions of the beam guiding elements.

The beam guiding device is intended in particular for use in an illumination system with at least two free-electron lasers (FEL) and a plurality of scanners.

The beam guiding elements are, in particular, mirror devices or mirror elements.

In accordance with a further aspect of the invention, the at least one beam guidance element can be displaced in a controlled manner by means of a control device. By means of the control device, in particular a precise control of the time sequence of the assignment change is possible. The control device can be software-supported. With the aid of the control device, in particular the distribution of the illumination radiation to the different outputs and thus to the different scanners can be optimized. In particular, it is possible to adapt the assignment of the inputs to the outputs to the exposure time of the dies. As a result, a throughput loss, in particular in the event of failure of one of the radiation sources, can be minimized.

In particular, the control device has an operating mode in which a periodically alternating assignment of one of the inputs of the radiation device to the outputs of the radiation device takes place, the period just corresponding to the duration of the exposure of a die.

In addition, the control device can preferably have a further operating mode, in which a constant assignment of the inputs of the radiation device to the outputs thereof is predetermined. According to one aspect of the invention, the beam guiding elements are arranged in a first displacement position in each case outside the beam path of the illumination radiation. In particular, they are arranged in such a way that they do not in each case lead to a deflection of the beam path in the first displacement position.

The position of the Strahlfuhrungs elements in their first displacement position is therefore also referred to as the ground state. In the ground state, each of the inputs of the beam guiding device is associated with exactly one of the outputs of the beam guiding device. According to a further aspect of the invention, in the case of an arrangement of all the beam guidance elements in their first displacement position, all the outputs of the beam guidance device can be acted on simultaneously with illumination radiation.

In the ground state, in particular, the first of the FEL can supply illumination radiation to a first subset of the scanners, while the second of the FEL supplies illuminating radiation to a second subset of the scanners disjoint therefrom.

According to one aspect of the invention, the assignment of at least one of the outputs to one of the inputs, that is to say the assignment of at least one of the scanners to one of the FELs, is changed by a displacement of one of the beam guidance elements into a second displacement position in the beam path of the illumination radiation.

According to one aspect of the invention, it is in particular possible to change the assignment of one of the inputs to one of the outputs by shifting one of the beam guidance elements into the second displacement position. Specifically, this means that the illumination radiation from a single one of the two FELs can be switched back and forth between the two disjoint subsets of the scanners by displacing one of the beam-guiding elements between its two displacement positions. In an arrangement of one of the beam guiding elements in its second displacement position, in particular only one of the outputs can be exposed to illumination radiation at a specific time. This means that at any one time only amount of the scanner can be supplied simultaneously with illumination radiation. As will be explained below, however, it is possible to achieve by targeted control of the displacement of the corresponding beam guiding element that different scanners are supplied sequentially, in particular alternately, with illumination radiation. In this case, a possible loss of production can be reduced by suitable control of the displacement of the corresponding beam guiding element, in particular minimized, preferably prevented.

According to one aspect of the invention, at least two of the beam-guiding elements with a frequency of at least 1 Hz can be displaced between a first and a second displacement position. This allows a sufficiently fast switching of the beam path of the illumination radiation from one of the inputs to at least two different outputs. The frequency with which the beam guiding elements can be displaced may be in particular at least 2 Hz, in particular at least 3 Hz, in particular at least 5 Hz, in particular at least 10 Hz.

The beam guiding device may also comprise further beam guiding elements which have a lower displacement frequency. Such beam guidance elements may be advantageous in order to achieve that the illumination radiation from the different FELs at identical outputs has an identical direction, in particular an identical directional distribution. The slower of the beam guiding elements can remain in its second displacement position in particular during the entire maintenance interval. According to the invention, it has been recognized that it is therefore sufficient if the corresponding beam guiding element can only be displaced quasi-statically.

According to one aspect of the invention, the beam guiding elements each comprise at least one rotatably mounted mirror device. The mirror device can in particular have a plurality of reflection surfaces. In particular, it can have a plurality of radiation-transmissive regions. In particular, it has a controllable rotational frequency. The mirror device preferably has a constant angular velocity apart from the controllable frequency. Acceleration and deceleration processes can thus be avoided. It has been found that it is advantageous for the displacement of the beam-guiding elements when they are displaced along a tangent to their reflection surface. For a plane mirror, this corresponds to a straight-line displacement parallel to the reflection surface. In the case of a curved mirror, in particular a mirror with a constant radius of curvature, this can be achieved by means of a circular displacement, that is to say a pivoting.

The improvement of such a beam-guiding element is a further object of the invention. According to one aspect of the invention, the beam-guiding element has a plurality of curved Ref formed surfaces whose radius of curvature just corresponds to their distance from the axis of rotation. In this way it can be achieved that the deflection of the illumination radiation by means of the beam guidance element is constant even during a rotation thereof for a certain period of time. The deflection is then switched almost instantaneously when the illumination radiation no longer falls on the same reflection surface due to the rotation of the beam guiding element.

The number of reflection surfaces of the beam guiding element is in particular at least 2. It can be 3, 4, 5, 6 or more than 6.

According to a further aspect of the invention, adjacent reflection surfaces are separated from each other by an intermediate region. The intermediate regions can in particular be designed to be transparent to radiation. In this case, the illumination radiation can pass through the beam guide element unaffected by this, as long as it does not impinge on one of the reflection surfaces. The beam guide element thus makes it possible to direct the illumination radiation periodically in different, predetermined directions. In particular, it makes it possible to steer the illumination radiation alternately in two different directions.

In the case of a uniform rotation of the beam guiding element, the duration for which the illuminating radiation is directed in a specific direction can be influenced by the angular range covered by the reflection surfaces or the radiation-permeable intermediate regions. be flown. The angle ranges can be the same in each case. They can also be different.

Further objects of the invention are to improve a lighting system for a projection exposure system and such a projection exposure system.

These objects are achieved by a lighting system with a beam guiding device according to the preceding description. The advantages result from those of the beam guiding device.

The radiation sources of the illumination system are, in particular, free-electron lasers (FEL).

With the aid of the beam-guiding device, it is possible, in particular, to divide illumination radiation from a single, two or more radiation sources, in particular in the form of free-electron lasers (FEL), into a plurality of scanners so that in the ground state each of the FELs forms a disjoint subset of Scanners supplied with illumination radiation, in case of failure of one of the FEL but the other FEL both subsets of the scanner, in particular all scanners of the projection exposure system, supplied with illumination radiation.

By the illumination system according to the invention, in particular by the beam guiding device, in particular the loss of production, which can be caused by the failure of a FEL, in particular due to maintenance work, can be reduced, in particular prevented.

According to one aspect of the invention, the beam guidance devices are each arranged in the beam path of the illumination radiation behind a decoupling unit. This makes it possible to flexibly switch illumination radiation back and forth between paired scanners of different subsets.

The decoupling unit serves to generate a plurality of individual output jets from a collection output beam. The individual output jets are each used to supply individual Scanner with illumination radiation. The collection output beam may be formed with beamforming optics from a raw beam emitted by the radiation source.

According to one aspect of the invention, each of the two radiation sources is assigned a group of N scanners and each scanners of the one group to assign a specific scanner of the other group, wherein for each two associated scanner different groups a beam guiding device according to the preceding description is provided , The scanners of the different groups are assigned in pairs in particular. In this case, it is possible by means of the beam-guiding device to control, for each pair of scanners, whether or, in particular, at what time the illumination radiation is guided by the radiation sources to which the scanner. In particular, it is possible to switch the illumination radiation from one of the radiation sources back and forth between the two scanners associated therewith, without this affecting the supply of illumination radiation to the remaining scanners of the projection exposure system.

This improves the flexibility of supplying the individual scanners with illumination radiation. As a result, the production loss can be further reduced, in particular minimized, in particular completely prevented. Details on this can be found in a method described in more detail below.

According to a further aspect of the invention, the beam guiding device is arranged in the beam path of the illumination radiation in front of a decoupling unit.

This has the advantage that at the same time the beam path of the illumination radiation for a plurality of the scanner can be influenced by means of the beam guiding device.

In this variant, additional optical components, for example for beam shaping and / or components of the coupling-out optical system, can also be integrated into the beam guiding device. In principle, it is possible to form the beam guiding device and the coupling-out optical system as a single optical device, in particular as a single optical module. The beam guiding device can be integrated in particular in the coupling-out optical system. It is also possible to integrate the coupling-out optics into the deflection device.

According to one aspect of the invention, each of the two radiation sources is assigned in each case a group of scanners and a beam guiding device according to the preceding description, wherein the assignment of the scanners of a group to one of the two radiation sources can be changed with the aid of the beam guiding device.

This allows a particularly simple change of the assignment of the scanner to the radiation sources.

The advantages of the projection exposure system result from those of the lighting system.

By the illumination system according to the invention, in particular by the beam guiding device, a production loss in case of failure of one of the FELs can be reduced, in particular completely avoided.

By means of the beam guiding device according to the invention, in general, the radiation from a single FEL can be distributed particularly efficiently to two groups of scanners. This leads in particular to an increase in efficiency, in particular to an increase in throughput.

Another object of the invention is to improve a method of operating a projection exposure system.

This object is achieved by a method in which different scanners of a projection exposure system are supplied with illumination radiation from a single radiation source in the form of a FEL, wherein the illumination radiation from this FEL can be interrupted at intervals by means of a beam guidance device according to the preceding description. different the scanner is deflected. In this case, the dies can be assigned to different scanners, taking into account their possibly different sizes.

According to one aspect of the invention, the assignment of the dies to the scanners is determined such that the production losses caused by the failure of one of the FELs are reduced, in particular minimized, and in particular completely avoided. In other words, the assignment of the dies to the scanners is determined in such a way that the efficiency of the projection exposure system is increased, in particular maximized. In this case, in particular a dead time, in which no exposure of a die takes place, although illumination radiation is offered, can be reduced, in particular minimized, in particular completely avoided.

According to one aspect of the invention it can be provided to sort the to be exposed dies depending on their size, in particular to re-sort. In particular, these can be divided into two groups such that all dies of a first group are greater than or equal to all dies of a second group. The dies are then assigned to the scanners so that the scanners of the one group simultaneously and the scanners of the other group are simultaneously exposed. According to a further aspect of the invention, it is provided to determine pairs of dies which differ in their sizes at most by a predetermined maximum value, then to associate the corresponding scanners in pairs and to alternately expose the dies of the previously determined pairs, thereby alternately exposing them This each one of the beam guiding elements between its two displacement positions is shifted back and forth.

As a result, production losses can be particularly well reduced, in particular minimized.

The maximum size difference of the two dies of a pair is in particular at most 25%, in particular at most 10%, in particular at most 5%, in particular at most 3%, in particular at most 1%. According to another aspect of the invention, to determine the amount of N to be exposed in the given period of time, dies are selected from the total of dies N such that a size difference between the largest of this dies and the smallest of these dies is less than a maximum size difference of all dies.

Another object of the invention is to improve a method of servicing a projection exposure system.

This object is achieved by a method in which all the scanners of the projection exposure system are supplied with illumination radiation from the other of the FELs during the maintenance period of one of the FELs. In this case, it is provided in particular to guide the illumination radiation from the active FEL at intervals to different ones of the scanners. In this case, the dies can be assigned to different scanners, taking into account their possibly different sizes.

Another object of the invention is to improve a process for producing micro- or nanostructured devices.

This object is achieved by providing a projection exposure system according to the invention.

The process leads in particular to a reduced production loss and thus to an increased productivity. In particular, it leads to an increase in the averaged productivity over time of the individual scanners. Further advantages, details and details of the invention will become apparent from the description of embodiments with reference to FIGS. Show it:

1 is a schematic representation of the components of a projection exposure system with a plurality of scanners,

2 shows an illustration of the projection exposure system according to FIG. 1 with a changed beam guidance, a schematic representation of a first variant of a displaceable Strahlführungs E element, a schematic representation of another variant of a displaceable beam guiding element, a schematic representation of another variant of a displaceable Strahlführungs E ele- ment, a schematic representation of another variant of a displaceable Strahlführungs E ele- , A schematic representation of another variant of a displaceable Strahlführungs-E element, a schematic representation of another variant of a displaceable Strahlführungs E ele- ment, a schematic representation for explaining the timing of an operating mode for the projection exposure system of FIG. 1, a representation of FIG. 9 for the operating mode of the projection exposure system according to FIG. 2, a schematic representation of a further variant of the projection exposure system according to FIG. 1, FIG.

12 is a schematic representation of a variant of the operating mode according to FIG.

10 13 shows a representation corresponding to FIG. 12, in which the order of the scanners is shown sorted by way of example,

14 and 15 schematic representations of further variants of operating modes of the projection exposure system,

16 shows a schematic illustration of a further variant of a projection exposure system, FIG. 17 shows an illustration according to FIG. 10 of an alternative in which the dies are applied to the

Scanners 1 to 3 are the same length or longer than the dies on scanners 4 to 6, and

18A to 18D is a schematic, fragmentary representation of an alternative embodiment of the projection exposure system according to FIG. 1 with different displacement positions of the beam guiding elements, and

19 is a schematic representation of an alternative embodiment of the projection exposure system according to FIG. 1.

In the following, the essential components of a projection exposure system 1 will first be described with reference to FIG.

The subdivision of the projection exposure system 1 into subsystems, which is carried out subsequently, serves primarily to delineate them in a conceptual sense. The subsystems can form separate structural subsystems. However, the division into subsystems does not necessarily have to be reflected in a constructive demarcation.

The projection exposure system 1 comprises two radiation source modules 2 and a plurality of scanners 3i. The components of the radiation source modules 2 can also be combined in a single radiation source module 2. The radiation source modules 2 each comprise a radiation source 4 for generating illumination radiation 5.

The radiation source 4 is, in particular, a free electron laser (FEL). It can also be a synchrotron radiation source or a synchrotron radiation-based radiation source which generates coherent radiation with very high brilliance. As an example, reference is made to US 2007/0152171 Al and DE 103 58 225 B3 for such radiation sources.

The radiation source 4 has, for example, an average power in the range of 1 kW to 25 kW. It has a pulse rate in the range of 10 MHz to 10 GHz. Each individual radiation pulse may for example amount to an energy of 83 μΐ. With a radiation pulse length of 100 fs, this corresponds to a radiation pulse power of 833 MW. The radiation source 4 can also have a repetition rate in the kilohertz range, for example of 100 kHz, or in the low megahertz range, for example at 3 MHz, in the middle megahertz range, for example at 30 MHz, in the upper megahertz range, for example at 300 MHz or else in the gigahertz range, for example at 1 , 3 GHz, own.

The radiation source 4 is in particular an EUV radiation source. In particular, the radiation source 4 emits EUV radiation in the wavelength range, for example, between 2 nm and 30 nm, in particular between 2 nm and 15 nm.

The radiation source 4 emits the illumination radiation 5 in the form of a raw beam 6. The raw beam 6 has a very small divergence. The divergence of the raw beam 6 may be less than 10 mrad, in particular less than 1 mrad, in particular less than 100 μrad, in particular less than 10 μrad. To simplify the description of positional relationships, coordinates of a Cartesian xyz coordinate system are used below. The x-coordinate regularly tightens a bundle cross-section of the illumination radiation 5 with the y-coordinate. The z-direction runs regularly in the radiation direction of the illumination radiation 5. In the region of the object plane 21 or the image plane 24, the y-direction runs parallel to a scanning direction. The x-direction is perpendicular to the scan direction. The raw jet 6 is from the Radiation source 4 emitted in a certain direction. This will also be referred to as Poin- ting P in the following.

The raw beam 6 may have an optical conductivity which is less than 0.1 mm ² , in particular less than 0.01 mm ² . The optical conductivity is the smallest volume of a phase space which contains 90% of the energy of the illumination radiation 5 emitted by the radiation source 2. Definitions of the optical conductivity value corresponding thereto can be found, for example, in EP 1 072 957 A2 and US Pat. No. 6,198,793 B1. The radiation source modules 2 further each comprise one of the radiation source 4 downstream beam shaping optics 7. The beam shaping optics 7 serves to generate a collection output beam 8 from the raw beam 6. The collection output beam 8 has a very small divergence. The divergence of the collection output beam 8 can be less than 10 mrad, in particular less than 1 mrad, in particular less than 100 urad, in particular less than 10 urad.

By means of the beam shaping optics 7, in particular the diameter of the raw beam 6 or the collecting output beam 8 can be influenced. By means of the beam shaping optics 7, in particular a widening of the raw beam 6 can be achieved. The raw beam 6 can be expanded by means of the beam-shaping optical system 7, in particular by a factor of at least 1.5, in particular at least 2, in particular at least 3, in particular at least 5, in particular at least 10. The expansion factor is in particular smaller than 1000. It is also possible to expand the raw beam 6 differently in different directions. In particular, it can be widened more in an x-direction than in a y-direction. In this case, the y-direction in the region of the object field 1 corresponds to the scanning direction. The divergence of the collection output beam 8 may be smaller than the divergence, in particular smaller than half the divergence, of the raw beam 6.

Alternatively, the raw beam 6 may be widened more in a y-direction than in an x-direction. Specifically, the difference in the expansion factor may be approximately equal to the total number of the later-generated single output beams 10i. For further details of the beam shaping optics 7 reference is made to DE 10 2013 223 935.1, which is hereby incorporated into the present application. In particular, the beam-shaping optical system 7 can each have one or two beam-shaping mirror groups each having two mirrors. The beam-forming mirror groups are used in particular for beam shaping of the collection output beam 8 in mutually perpendicular planes, which run parallel to the propagation direction of the collection output beam 8.

The beam shaping optics 7 may also comprise further beam shaping mirrors. The beam-shaping optical unit 7 may in particular comprise cylinder mirrors, in particular at least one convex and at least one concave cylindrical mirror. It can also include mirrors with a freeform profile. Such mirrors each have a height profile which can not be represented as a conic section. By means of the beam shaping optics 7, the intensity profile of the raw beam 6 can also be influenced.

In addition, the radiation source module 2 may each comprise one of the beam shaping optics 7 downstream coupling-out 9. The coupling-out optical system 9 is used to generate a plurality of, namely, n, individual output beams 10i (i = 1 to n) from the collection output beam 8. The

Single output beams 10i each form radiation beams for illuminating an object field 1i. The individual output beams 10i are each associated with one of the scanners 3i. The radiation beams of the individual output beams 10i can each have a plurality of separate partial beams 12; include.

The radiation source module 2 is in each case arranged in particular in an evacuable housing.

The scanners 3i each comprise a beam guiding optics 13i and a projection optics 14i. The beam guiding optics 13i of the scanner 3i serve to guide the illuminating radiation 5, in particular the respective individual output beams 10i, to the object fields 11i of the individual scanners 3i. The projection optics 14; each serves to image a reticle 22 arranged in one of the object fields 11i; in an image field 23i, in particular on a wafer 23i arranged in the image field 23i.

In the sequence of the beam path of the illumination radiation 5, the radiation guidance optics 13i respectively comprise a deflection optics 15i, a coupling optics 16i, in particular in the form of a focusing assembly, and an illumination optics 17i. The coupling optics 16i may in particular also be designed as a Wolter type III collector.

The deflection optics 15i can also be integrated in the coupling-out optical system 9. The coupling-out optical system 9 can in particular be designed in such a way that it already deflects the individual output beams 10i in a desired direction. According to a variant, the deflection optics 15i as a whole can also be dispensed with. In general, the coupling-out optical system 9 and the deflection optics 15i can form a decoupling deflecting device. According to a further variant, the coupling-out optical system 9 can also be arranged in each case in the beam path after the deflection optics 15i. These different variants relate to all embodiments described below.

For different variants of the deflection optics 15i, reference is made, for example, to DE 10 2013 223 935.1, which is hereby incorporated into the present application as part of the present application.

In particular, the coupling-in optical system 16i serves to couple the illumination radiation 5, in particular one of the individual output beams 10i generated by the coupling-out optical system 9, into respectively one of the illumination optical systems 17i.

The beam guiding optics 13i together with the beam-shaping optical system 7 and the coupling-out optical system 9 form components of a lighting device 18. Each of the illumination optics 17i is one of the projection optics 14; assigned. Together, the mutually associated illumination optics 17i and the projection optics 14; also referred to as optical system 20i.

The illumination optical unit 17i serves in each case for the transfer of illumination radiation 5 to an object field 1 ii in an object plane 21; arranged reticle 22i. The projection optics 14; serves to image the reticle 22i, in particular for imaging structures on the reticle 22i, onto a wafer 25i arranged in an image field 23i in an image plane 24.

In particular, the projection exposure system 1 comprises at least two, in particular at least three, in particular at least four, in particular at least five, in particular at least six, in particular at least seven, in particular at least eight, in particular at least nine, in particular at least ten scanners 3i. The projection exposure system 1 may also comprise twenty or more scanners 3i. Depending on the design of the radiation source module 2, in particular depending on the number of radiation sources 4, the projection exposure system 1 can also comprise, for example, up to 100 scanners 3i.

The scanners 3i are supplied with illumination radiation 5 by the common radiation source modules 2, in particular by the radiation sources 4. The projection exposure system 1 is used to produce micro- or nano-structured components, in particular electronic semiconductor components.

The coupling-in optical system 16i is arranged in the beam path between the radiation source module 2, in particular the coupling-out optical system 9, and in each case one of the illumination optical systems 17i. It is designed in particular as a focusing assembly. It serves to transfer each of the individual output beams 10i into an intermediate focus 26i in an intermediate focus plane 27. The Intermediate focus 26i can be arranged in the region of a passage opening of a housing of the optical system 20i or of the scanner 3i. The housing is in particular evacuated.

The illumination optics 17i each comprise a first facet mirror and a second facet mirror whose function corresponds in each case to those known from the prior art. The first facet mirror may in particular be a field facet mirror. The second facet mirror may in particular be a pupil facet mirror. However, the second facet mirror may also be arranged at a distance from a pupil plane of the illumination optical system 17i. This general case is also called a specular reflector.

The facet mirrors each include a plurality of first and second facets, respectively. In operation of the projection exposure system 1, each of the first facets is associated with one of the second facets. The mutually associated facets each form an illumination channel of the illumination radiation 5 for illuminating the object field 1 Ii at a specific illumination angle.

The channel-wise assignment of the second facets to the first facets takes place as a function of a desired illumination, in particular of a predetermined illumination setting. The facets of the first facet mirror can be displaceable, in particular tiltable, in particular with two tilting degrees of freedom. The facets of the first facet mirror are in particular switchable between different positions. They are assigned in different switching positions different of the second facets. In each case, at least one switching position of the first facets may be provided, in which the illuminating radiation 5 impinging on them does not contribute to the illumination of the object field 1i. The facets of the first facet mirror can be designed as virtual facets. This is understood to mean that they are formed by a variable grouping of a plurality of individual mirrors, in particular a plurality of micromirrors. For details, reference is made to WO 2009/100856 AI, which is hereby incorporated as part of the present application in this.

The facets of the second facet mirror can accordingly be designed as virtual facets. They can also be correspondingly displaceable, in particular tiltable, be formed. The first facets are imaged into the object field 11i in the reticle or object plane 21 via the second facet mirror and optionally via a subsequent transmission optics (not shown in the figures) which comprises, for example, three EUV mirrors.

The individual illumination channels lead to the illumination of the object field 1 Ii with specific illumination angles. The totality of the illumination channels thus leads to an illumination angle distribution of the illumination of the object field 1 ii through the illumination optics 17 i. The illumination angle distribution is also referred to as the illumination setting.

In a further embodiment of the illumination optics 17i, in particular in the case of a suitable position of the entrance pupil of the projection optics 14i, the mirrors of the transmission optics in front of the object field 1i can also be dispensed with, which leads to a corresponding increase in transmission for the useful radiation bundle.

The reticle 22; with structures reflecting for the illumination radiation 5, 1 ii is arranged in the object plane 21 in the region of the object field 1. The reticle 22; is carried by a reticle holder. The reticle holder is controlled by a displacement device displaced.

The projection optics 14; In each case, the object field 1 ii is imaged into the image field 23 i in the image plane 24. In this image plane 24, the wafer 25i is arranged in the projection exposure. The wafer 25i has a photosensitive coating, which is exposed to the projection exposure system 1 during the projection exposure. The wafer 25i is carried by a wafer holder. The wafer holder is controlled by a displacement device displaced.

The displacement device of the reticle holder and the displacement device of the wafer holder can be in signal connection with one another. They are especially synchronized. The reticle 22; and the wafer 25i are in particular synchronized with each other displaceable.

On the reticle 22; structures are attached. The surface area on which the structures are mounted is referred to below as Die. The die is usually larger than that Object field I ii, therefore, for its imaging on the wafer 25i, a synchronized scanning movement of reticle 22; and wafer 25i is necessary. If during a period of the scanning process only a part of the object field 11i is covered by the die, then the remaining area of the object field 11i can be covered by means of movable reticle masking apertures.

As a result of the scanning and exposure process, structures are formed in the photosensitive coating on the wafer 25i, which in a first approximation represent a reduced image of the die. Such an image of the die on the wafer 25i will normally include all structures of one or more micro- or nano-lithographic devices, such as a wafer. Semiconductor chips. A die can therefore in particular include structures that belong to more than a single semiconductor chip after uncoiling a finished processed wafer 25i.

Each reticle 22; usually contains exactly one die. The maximum size of the reticle 22; is usually limited, and thus the maximum size of a Dies. A Die can however be smaller than this maximum size.

The various reticles 22i, each associated with a scanner 3i, may carry identical or different dies. The reticles 22; are generally automatically interchangeable and interchangeable between different 3i scanners. The projection exposure system 1 usually has a system for a specific reticle 22; be introduced into a particular scanner 3k, then subsequently by this scanner one or more wafers 25k are exposed by means of the corresponding Dies. Conversely, this means that the corresponding reticle 25i must be introduced into the scanner 3k in order to expose a specific die.

In the following, an advantageous embodiment of the illumination system 19 will be described.

It has been recognized that as the radiation sources 4 advantageously free electron laser (FEL) or synchrotron-based radiation source can be used. A FEL scales very well, which means that it can be operated particularly economically if it is designed to be large enough to supply a plurality of scanners 3i with illumination radiation 5. In particular, the FEL can supply illuminating radiation 5 to up to eight, ten, twelve or even twenty scanners in each case.

If one of the FEL fails, for example because it has to be shut down for maintenance, this has consequences for a corresponding plurality of scanners 3i. Without suitable compensation measures, the scanners 3i supplied with illumination radiation 5 in the ground state by this FEL are then at rest. This is not desirable for efficiency reasons.

According to the invention, it has been recognized that this problem can be solved by the fact that the projection exposure system 1 comprises at least two FELs as radiation sources 4i. In the following, the terms radiation source 4i and FEL are used interchangeably.

By means of a beam guiding device 28, the illumination radiation from the two FELs can be flexibly divided as needed into the different scanners 3i. In this case, provision is made in particular for the first FEL in a ground state to supply illumination radiation to a first subset of the scanners 3i to 3N, while the second FEL in the ground state supplies a second subset of the scanners 3N + 1 to 3 ₂ N with illumination radiation 5. If one of the FEL fails, for example because it has to be switched off for maintenance work, the other of the FELs can supply all the scanners 3i with illumination radiation 5. This will be described in more detail below. The beam guiding device 28 can form a component of the radiation source module 2. In particular, it forms part of the illumination system 19. The two subsets may also comprise different numbers of scanners 3i.

The core idea of the present invention will be described below with reference to a projection exposure system 1 with two radiation sources 4i, 4 ₂ . This is not meant to be limiting. The inventive principle can be easily extended to the case of a larger number of radiation sources 4i. The projection exposure system 1 can in particular also comprise three, four, five, six or more radiation sources 4i, in particular in the form of FEL. According to the invention, it has been recognized that there are time intervals during the exposure of the wafers 25i during which at least some of the scanners 3i need not be supplied with illumination radiation 5 or at least not with the maximum intensity of the illumination radiation 5. This is the case, for example, if the so-called reticle masking diaphragms are partially closed, in particular completely. This may be the case in particular in the period between the exposure of two consecutive dies. This may in particular be the case when the wafer 25i is displaced while the associated reticle 22; stands still. According to the invention, it has been recognized that a given scanner 3i typically only needs to be supplied with illumination radiation 5 for at most 70%, in particular only at most 60%, in particular at most approximately 55% of the time. According to the invention, it has further been recognized that this fact can be exploited in order to guide the illumination radiation 5 provided for this scanner 3i to another of the scanners 3i in the time intervals in which a particular scanner 3i does not need to be supplied with illumination radiation 5.

In the following, different embodiments of the beam guiding device 28 as well as the method for guiding the illumination radiation 5 provided by means of this will be described.

According to a first embodiment shown in FIGS. 1 and 2, the beam guiding device 28 comprises a first mirror 29i, 29 ₂ and a second mirror for each of the FELs

The mirrors 2% 30i generally form beam guiding elements. The mirrors 2% 30i are displaceable, in particular actuatable displaceable.

The first mirror 29i in each case has a reflection surface 33. In a ground state exemplified in FIG. 1, all the mirrors 2% 30i of the beam guiding device 28 are arranged outside the beam path of the illumination radiation 5. assigns. The mirrors 2% 30i of the beam guiding device 28 are thus functionless in the ground state.

The mirrors 2% 30i are in particular displaceable in each case between two displacement positions. In this case, the first displacement position is such that the mirrors 2% 30i are arranged outside the beam path of the illumination radiation 5. The second displacement position of the mirrors 2% 30i is just selected or set such that the beam path of the illumination radiation 5 is guided in a second displacement position of the second radiation source 4 ₂ to the first subset of the scanners 3i to 3N when the mirrors 29 ₂ , 30 _{2 are} positioned is (see Fig. 2). Accordingly, the illumination radiation 5 of the mirrors 29i, 30i is guided in its second displacement position from the first radiation source 4i to the second subset of the scanners 3N + 1 to 3 ₂ N.

The mirrors 2% 30i are in particular designed such that the illumination radiation 5 is guided by one of the two radiation sources 4i at an arrangement of the corresponding mirrors 2% 30i in their second displacement position at an angle of incidence to the coupling-out optical system 3, in particular to the input of the corresponding scanner 3j, which just corresponds to the angle of incidence of the illumination radiation 5 from the other radiation source 4j in the ground state. For the scanners 3i, there is thus no difference with respect to the angles of incidence of the illumination radiation 5 from a displacement of the mirrors 2i.

Generally, by means of the beam guiding device 28, in particular by displacement of the mirrors 2% 30i, a guidance of the illumination radiation 5 between at least two inputs of the beam guiding device 28 and at least two outputs thereof can be controlled. In this case, the FELs provided as radiation sources 4i are each assigned to one of the inputs of the beam guiding device 28. The subsets of the scanners 3i are each associated with one of the outputs of the beam-guiding device 28 (see the schematic representation in the figures).

Without restricting generality, for the purpose of explanation of the idea of the invention, the following example assumes that the radiation source 4i is to be switched off for maintenance purposes (see FIG. 2). In this case, it is provided, the second mirror 30 ₂ in his second shift position. It can remain in the second displacement position for the entire duration of the maintenance process. It is therefore sufficient if the second mirror 30i are slow, quasi-static displaceable. The first mirror 29 ₂ is displaced back and forth between the first subset of the scanners 3i to 3N and the second subset of the scanners 3N + 1 to 3 ₂ N during the maintenance operation of the first radiation source 4i between its first and second displacement positions for switching the illumination radiation 5 , In FIG. 2, the two beam paths of the illumination radiation 5, which result from the different displacement positions of the first mirror 29 ₂ , are shown by way of example with a dashed line corresponding to that of the mirror 29 ₂ in the different displacement positions.

The first mirror 29i is preferably displaceable back and forth between the first and second displacement position at a frequency of at least 1 Hz, in particular at least 2 Hz, in particular at least 3 Hz, in particular at least 5 Hz, in particular at least 10 Hz.

The actuators provided for displacing the mirrors 29i, 30i fulfill the usual requirements for the actuators of a projection exposure system 1, in particular an EUV projection exposure system 1.

The actuators are vacuum-compatible or encapsulated so that they are suitable for vacuum. They are insensitive to atomic hydrogen, especially against ionized hydrogen. They contain no substances which can outgas, in particular no substances which can lead to contamination of the mirrors of the EUV projection exposure system, or they are encapsulated in such a way that leakage of such substances is prevented.

The actuators are advantageously abrasion-free, i.e. no particles are released upon movement of the actuated components, or the actuator is encapsulated to prevent the escape of particulate matter.

The actuators are low-maintenance, preferably maintenance-free. To control the displacement of the mirror 2% 30i, a control device 35 is provided. The control device 35 may comprise a computing unit.

In the following, different options of the displacement of the first mirror 29i will be described with reference to FIGS. 3 to 8.

In FIGS. 3 to 8, the direction of movement of the first mirror 29i is illustrated schematically in each case by a double arrow 32. As shown schematically in FIG. 3, the first mirror 29i can be mounted such that it can be actuated in a pivotable manner about an axis of rotation 31.

Alternatively, the mirror 29i, as shown by way of example in FIG. 4, can be displaced linearly, in particular in the direction perpendicular to the illumination radiation 5.

Particularly suitable actuators are Lorentz actuators, in particular with a coil magnet arrangement. Such actuators can cause both rotational and Verschwenkbewegun- conditions as well as translational movements. It can also be used pneumatic and / or hydraulic actuators. In principle, other actuator types, such as e.g. Piezoactuators, bimetallic actuators or shape memory alloy based actuators may be used.

Bearings can be designed as solid joints. These are advantageously formed without friction and / or abrasion. The bearings can also be designed as magnetic bearings. These may be in particular contactless.

Furthermore, bearings can be designed as rolling bearings, in particular as ball bearings. For lubrication of the bearings vacuum-compatible lubricants may be provided. It can also be used plain bearings. These are advantageously frictionless or so encapsulated that abrasion can not leave the camp. According to the invention, it has been recognized that it is advantageous for the precision of the positioning of the mirror 29i in the displacement positions when it is displaced along a tangent to its reflection surface. Corresponding variants are shown schematically in FIGS. 5 and 6. In the variant according to FIG. 5, the reflection surface of the first mirror 29i is curved. Their radius of curvature in this case corresponds in particular to the distance to the axis of rotation 31.

In the case of a curved embodiment of the first mirror 29i, it is preferably provided that the second mirror 30i, which follows this in the beam path of the illumination radiation 5, is also curved. The second mirror 30i belonging to the first mirror 29i is in particular designed such that a fanning of the illumination beam caused by the curvature of the first mirror 29i is compensated again by a suitable curvature of the second mirror 30i. In a plan embodiment of the reflection surface of the mirror 29i, the displacement along a tangent to the reflection surface corresponds precisely to a linear displacement in the reflection surface plane. This alternative is shown schematically in FIG.

With a design and displaceability of the first mirror 29i according to one of the figures 5 or 6, the precise reaching of the displacement positions with respect to the direction of displacement is not particularly important. As long as the illumination radiation 5 impinges on the mirror 29i, it is deflected regardless of its exact displacement position. As a result, the displacement of the first mirror 2%, in particular its rapid displacement, greatly simplified.

FIGS. 7 and 8 show two further alternatives for the embodiment of the first mirror 29i and its arrangement in the beam path of the illumination radiation 5. In these alternatives, the first mirror 29i is designed as a rotatably mounted mirror device. In the exemplary FIGS. 7 and 8, the first mirror 29i has four reflection surfaces 33 each.

The mirror 29i may also have a different number of reflection surfaces 33. In particular, it has at least one, in particular at least two, in particular at least three, in particular in particular at least four, in particular at least five, in particular at least six reflection surfaces 33 on.

The design of the reflection surface 33 corresponds in each case to that of the embodiment shown in FIG. 5.

The first mirror 29i is rotatably mounted in particular about the rotation axis 31. It can have a constant rotational frequency. The rotation frequency can be controllable. With a uniform rotation, it is fixed to what proportion of the rotation period the illumination radiation 5 falls on one of the reflection surfaces 33. The mirror 29i is designed in particular in such a way that the reflection surfaces 33 make up in total just half of the circumferential area of the first mirror 29i. With a constant rotation, this leads to a duty ratio of 1: 1, that is, the illumination radiation 5 falls on average one of the reflection surfaces 33 as long as it falls on one of the two reflection surfaces 33 provided between the intermediate region 34.

Alternative duty cycles are also possible. These are in particular between 45:55 and 55:45.

In the embodiment shown in FIG. 8, the intermediate regions 34 are designed to be radiation-permeable.

The rotation frequency can be adapted in particular to the size of the to be exposed Dies on the wafers 25i. Once the size of the die is specified, the rotation frequency, once properly adjusted, can be kept constant. In particular, there is no angular acceleration during the actual operation, that is, during the exposure of the dies, necessary.

In particular, the rotational frequency can be adjusted such that the duration of the period during which one of the reflection surfaces 33 of the mirror 29i is located in the beam path of the illumination radiation corresponds precisely to the exposure duration of one of the dies. Accordingly, the duration for which the illumination radiation is applied to one of the intermediate regions 34 between two of the reflecting surfaces 33 falls, just the duration of the exposure of a Dies correspond.

The mirror 29i is preferably balanced. This can be achieved, for example, by a suitable shaping of a mirror frame, which can be arranged, for example, in FIGS. 7 and 8 in front of and / or behind the plane of the drawing.

In the ground state, that is to say when all of the radiation sources 4i emit illumination radiation 5, the first mirror 29 i is in particular arranged such that it does not lead to a deflection of the illumination radiation 5. For this purpose, the first mirror 29i can be linearly displaceable, that is to say displaceable, in addition to its rotatability. In particular, it is possible to mount the mirror 29i such that its axis of rotation 31 is linearly displaceable, that is to say displaceable.

The first mirrors 29i can also be designed as desired in the embodiments described below in accordance with one of the alternatives described with reference to FIGS. 3 to 8.

In the following, a method for operating the projection exposure system 1, in particular a method for the maintenance thereof, will be described. In the ground state, which is also referred to as a normal operating mode, both radiation sources 4i are functional.

The first FEL continuously supplies illumination 3 to the scanners 3i to 3N. The pulse structure of the FEL is ignored here because it is irrelevant to the present invention. Analogously, the second FEL supplies the scanners 3N + 1 to 3 ₂ N with illuminating radiation 5. A time sequence of this operating mode is shown by way of example for N = 3 in FIG. 9. Each row corresponds to the supply of one of the scanners 3i with illumination radiation 5. The hatchings make it clear from which of the FELs the respective scanner 3i is supplied with illumination radiation 5. Without limiting the generality, illumination radiation 5 from the first FEL is characterized by a vertical hatch r, while illumination radiation 5 from the second FEL is characterized by a horizontal hatch. With a continuous hatching the periods are marked, in which a particular of the scanner 3i illumination radiation 5 is provided and actually used by this. interrupted Hatched represent time periods in which a specific of the scanner 3i illumination radiation 5 is provided, but this is not or not fully used by the corresponding scanner 3i, for example, because the reticle masking aperture are partially or completely closed.

These periods may be different for the different scanners 3i. This is due, for example, to the fact that a maximum length and width of the die is predetermined by the structure of the projection apparatus 1, but no minimum length and width of the same. If a certain die is smaller than the maximum possible size, the exposure of it takes correspondingly shorter. The different durations of the periods may also be due to the fact that for certain dies the scan must be slowed down, e.g. because for this application, a higher radiation dose on the photosensitive layer of the wafer 25i is necessary. This can be regarded as an effective extension of the Dies, and the term of the length of the Dies is to be understood as follows.

FIG. 10 shows by way of example the operation of the projection exposure system 1 in the maintenance mode, that is to say when only one of the FELs, in this case the first FEL, is available. In this case, it is provided to distribute the illumination radiation 5 from the first FEL alternately to the scanners 3i to 3N and to the scanners 3N + 1 to 3 ₂ N ZU.

Without hatching, the time periods during which the corresponding scanners 3i are not supplied with illumination radiation 5 are shown.

The illumination radiation 5 is guided in each case for the duration of an interval L to a subset of the scanner 3i. The intervals L all have the same length T. In other words, the two subsets, in particular the two disjoint subsets of the scanners 3i to 3N and 3N + 1 to 3 ₂ N, are alternately supplied with illumination radiation 5. The duty cycle is 1: 1. The duty cycle can also differ slightly from 1: 1, but then all even time intervals continue to be the same length, I ₀ = I ₂ = I ₄ =. .., and all odd time intervals are the same length, Ii = I3 = I5 =. ... This can be used advantageously in particular when the different This can not be arbitrarily distributed to the scanners 3i, but all of this on the scanners 3i to 3N are the same or longer than the dies on the scanners 3N + 1 to 3 ₂ N. Analogously this that all this are on the scanners 3i to 3N of the same length or shorter This on the scanners 3N + I to 3 N _2. This can be achieved, for example, by means of central production planning and control. FIG. 17 shows a representation analogous to FIG. 10 of such a situation in which all dies on the scanners 3i to 3N are the same length or longer than the dies on the scanners 3N + 1 to 3 ₂ N.

According to the invention, it has been found that, in the case where all dies are equal in size and have the maximum possible die size, the time required to expose all dies in maintenance mode only increases by about 10% compared to the normal operating mode. The productivity decreases only by about 10%. The production loss caused by the failure of one of the FELs is therefore only about 10%>. The beam guiding device 28 can advantageously be combined with other functions. FIGS. 18A to 18D show an exemplary combination with a deflection function. This deflection function can be identical to that of the deflection group 15, but also fulfill other deflection functions. In the configuration shown in FIG. 18A, mirrors 291 and 30 ₂ are displaced such that they direct the illuminating radiation 5 onto deflecting mirrors 36. The mirrors 29 ₂ and 30 i are displaced such that they do not influence the illumination radiation 5. In the configuration shown in FIG. 18D, the mirrors 29 ₂ and 30 i are displaced such that the illumination radiation 5 is directed to other associated deflection mirrors 36, while the mirrors 291 and 30 ₂ are displaced such that they do not affect the illumination radiation 5. Both with the configuration according to FIG. 18A and with the configuration according to FIG

18D, the illumination radiation 5i, 5 _{2 is directed} from both radiation sources 4i, 4 ₂ to the scanners 3i. For simplicity, only two illumination optics 17i, 17 ₂ are shown in the figures. This is not meant to be limiting. The illumination radiation 5 can also be divided in this embodiment, on a plurality of scanners 3i with a plurality of optical systems 20i. In this regard, reference is made to the description of the embodiment according to FIG. In FIGS. 18B and 18C, configurations of the beam guiding device 28 are schematically illustrated, which are provided in the event that one of the radiation sources 4i or 4 ₂ fails, which may be necessary, for example, due to maintenance work.

In the configuration shown in FIG. 18B, only the radiation source 4i supplies the scanners 3i with illumination radiation 5. In this case, the mirror 30i is displaced into the beam path of the illumination radiation 5 which is emitted by the first radiation source 4i. He can be left in this position. To convert which the scanner 3i is supplied with illumination radiation 5, as previously described, the mirror 291 can be displaced between two displacement positions. For details, again refer to the previous description.

Accordingly, in the configuration illustrated in FIG. 18C, the mirrors 29i and 30i are arranged outside the beam path of the illumination radiation 5. The mirror 30 ₂ can be arranged stationarily in the beam path of the illumination radiation 5. The mirror 29 ₂ is displaceable to guide the illumination radiation 5 to different subsets of the scanner 3 i between two displacement positions. In this alternative, the mirror 30 may be ₂ stationary. In particular, it can form a reference point for the arrangement of the beam guiding device 28.

In the variant according to FIGS. 18A to 18D, the number of reflections of the illumination radiation 5 in the beam path between the beam shaping optics 7i and the illumination optics 17i is independent of the configuration of the beam guiding device 28. This can be advantageous. As a result, in particular the on the reticle 22; incident dose of the illumination radiation 5 are kept constant regardless of the configuration of the beam guiding device 28. Furthermore, the number of reflections of the illumination radiation 5 in the beam path between the beam shaping optics 7i and the illumination optics 17i can be identical to the number of reflections that would be necessary for a pure deflection by deflecting mirrors 36. For the functionality of the displacement of the beam path then no additional reflection is necessary. In this alternative, the mirrors can form 2% 30i components of the deflection optics 15i.

According to the invention, it has been recognized that the loss of production caused by the failure of one of the FELs can under certain circumstances be further reduced. For this purpose, it is intended to associate the scanners 3i in pairs. In particular, it is provided to assign one of the scanners 3i to 3N and one of the scanners 3N + 1 to 3 ₂ N to one another in each case. For example, the scanners 3k and 3 ₂ N + ik (k = 1... N) can each be assigned to one another. This is shown by way of example in FIG. 11.

According to the alternative shown in FIG. 11, a beam guiding device 28 with first and second mirrors 2% 30i is provided for each pair of associated scanners 3k, 3 ₂ N + ik. The illumination radiation 5 can thus be selectively redistributed between the scanners 3k and 3 ₂ N + ik. This leads to greater flexibility. If differently sized dies are to be exposed on the wafers 25i, it is provided according to the invention to expose this similar quantity on the respective associated scanners 3k, 3 ₂ N + ik of a pair. This can be achieved in particular by a central production planning and control of all the scanners 3i of the projection exposure system 1. In contrast to the exemplary embodiment described above, it is therefore sufficient if pairs of dies can be found with approximately the same size. These can then be respectively produced on the two scanners 3k, 3 ₂ N + ik, which are coupled together. It is no longer necessary for all dies to be approximately equal in size for efficient operation mode. A corresponding operating mode is shown by way of example in FIG. 12. In this case, the production loss could be reduced to zero, despite the different sizes of the individual dies. This is due to the fact that in each case pairs of the same size could be found.

FIG. 13 shows the same situation as FIG. 12, wherein the sequence of the scanners according to the embodiment shown by way of example in FIG. 11 is shown sorted. In this exemplifying embodiment, the intervals L for switching the illumination radiation 5 back and forth between each two of the scanners 3k and 3 ₂ N + ik are the same length. However, the intervals L of a particular pair of scanners 3k, 3 ₂ N + ik are independent of those of another pair. If pairs of similar sizes, preferably identical sizes, can be found in pairs, the efficiency can be improved, in particular maximized, by this pairwise grouping.

It can be provided, in particular, for the maintenance period of one of the scanners to be exposed to be selected in such a way that in each case pairs of dies can be found whose size differs at most by a predetermined maximum value. The maximum size difference of the two Dies of a pair may in particular be at most 25%, in particular at most 10%, in particular at most 5%, in particular at most 3%, in particular at most 1%. In this case, it is possible to avoid the production loss particularly largely, in particular completely.

Another example is shown by way of example in FIG. 14. In this embodiment, pairs of dies have very different sizes. For example, the dies exposed on the scanners 3 ₂ and 3 ₅ are only about half the size of the dies exposed on the scanners 3i and 3 ₆ . The period T for the switching of the illumination radiation 5 is thus only about half as long in the pair of scanners 3 ₂ , 3 ₅ as in the case of the pair of scanners 3 i, 3 ₆ .

By way of example, FIG. 15 shows the same situation as in FIG. 14, but in the case where the scanners 3i are not grouped in pairs depending on the size of the die. As can be seen from FIG. 15, dead times 35 occur in this case, with one of the scanners 3i already having finished exposure before the respectively associated other scanner 3j again requires illumination radiation 5.

According to a further alternative of the invention, the flexibility of beam guidance from the FEL to the different scanners 3i can be further increased. It is basically possible to provide N scanners 3i up to N (N-1) beam guiding devices 21. In this case, it is possible to redistribute the illumination radiation 5 arbitrarily in pairs between the scanners 3i. In other words, each scanner 3i of the one FEL can be used with each scanner 3j of the connected to other FELs. For clarity, this option is not shown in a figure.

An equivalent alternative is shown in FIG. Each of the two beam shaping optics 7i generates a discrete number of individual output beams 10i instead of a collective output beam 8 with illumination light 5. Mirrors 29i, k direct the beam to the scanner 3k in a first displacement position. This displacement position is shown in solid lines in the figure. In a second displacement position, the mirror 29i, k does not affect the beam 10i. A mirror in such a second displacement position is shown in dashed lines in the figure. If a scanner 3k, which was previously supplied with illumination light 5 by the beam 10i, no longer needs illumination light 5, the beam 10i can now be used to illuminate the scanner 3k ', which previously received no illumination light. For this switching, only the mirrors 29i, k and 29i, k 'have to be displaced, while all other mirrors 29 can remain unchanged. Of the two mirrors 29i, k and 29i, k ', only one has to be moved quickly, namely the one in front in the beam path.

In all of these alternatives, the efficiency of the projection exposure system 1 can be maximized if one of the FELs fails. The production loss can be reduced as best as possible, that is, in particular minimized. For splitting the illumination radiation 5 onto the individual scanners 3i, in particular for controlling the displacement of the mirrors 29i of the beam guiding device 28, a control device 35 is provided in this case in particular.

By means of the control device 35, in particular the distribution of the illumination radiation 5 to the different scanners 3i can be optimized.

In the following, another alternative will be described with reference to FIG. In the embodiment according to FIG. 16, the first mirrors 29i form outcoupling mirrors for decoupling a single output beam 10i from the collection output beam 8. In this case, a separate coupling-out optical system 9 can be dispensed with. However, it is also possible, in addition to the first mirrors 29i, to provide a coupling-out optical system 9 with further components. In this embodiment, each of the scanners 3i are each assigned two outcoupling mirrors 29i. With the aid of the coupling-out mirror 29i, it is possible to guide illumination radiation 5 from each of the two FELs 4i, 4 ₂ to a specific one of the scanners 3i. In this embodiment, only 2N actuators are necessary for N scanners 3i. However, in this case, the mirrors 29i have more than two displacement positions. The number of displacement positions of the mirrors 29i corresponds in particular to the number of scanners 3i. Advantageously, the mirrors 29i are continuously displaceable in this embodiment.

In addition, the control device 35 is more complex in this embodiment. This is due to the fact that when the illumination radiation 5 switches between two specific scanners 3i, 3j, it may be necessary to displace mirrors 29k, which are not directly associated with one of these two scanners 3i, 3j.

In the following, further aspects of the different embodiments are described in keywords.

In order to be able to evaluate the various options for the maintenance mode, it has to be taken into account that the projection exposure system 1 is centrally controlled. If it is foreseeable that one of the FELs has to be shut down, for example for maintenance purposes, ie has to be switched off, it can be attempted in the embodiment according to FIG. 1 to re-sort the production process so that in the maintenance period always the same size dies on all of them Scanner 3i be exposed. Since changing the reticles 22; is a non-trivial action and may not be required as many wafers 25i with the same size Dies, this goal may be achieved only partially. In this case, it comes in the embodiment of FIG. 1 to an unavoidable loss of production. However, this loss of production is less than that which would occur without the beam guiding device 28 in case of failure of one of the FELs.

The greater the flexibility of the redistribution of the illumination radiation 5 between the different FELs and the scanners 3i, the more the production loss can be decrease one of the FELs. In particular, in the embodiment not shown in a figure with N (N-1) beam guiding devices 28 or in the embodiment according to FIG. 16, maximum efficiency can always be achieved even without central production planning, that is to say the loss of production, which is due to failure of one of the FELs - gently, minimize.

Although the maximum efficiency can not always be achieved in the exemplary embodiment according to FIG. 11, the production loss caused by failure of one of the FELs can generally be reduced considerably. In particular, if the size differences of the different dies are not too large and / or if at least pairs of similar sized dies can be found, the maximum or at least almost the maximum efficiency of the projection exposure system 1 can be achieved with the embodiment according to FIG. This embodiment also has the advantage of a much less complex mechanical structure.

In the embodiment according to FIG. 11, the efficiency of the projection exposure system 1 can be increased, in particular, by central production planning. In order to increase the efficiency, in particular to reduce the loss of production during a maintenance period, it is provided according to the invention in particular to select the amount of the to be exposed in the maintenance period targeted. In particular, it may be provided to select a quantity of similar size for the maintenance period such that the dies to be exposed on the different scanners have sizes which differ in their sizes at most by a predetermined maximum value. The maximum size difference between the largest and the smallest to be exposed is in particular at most 25%, in particular at most 20%, in particular at most 15%, in particular at most 10%, in particular at most 5%, in particular at most 3%, in particular at most 2%. >, in particular not more than 1%>. Preferably, all the dies to be exposed have the same size.

In the case of an embodiment according to FIG. 11, it is sufficient if pairs of equal size or at least a similar size can be found. In this case, it is sufficient, in particular, if it can be found for the maintenance period to be exposed Dies, so that the two Dies in each case at most differ only in their size by the previously mentioned maximum value.

In the following, further aspects of the invention will be described.

When switching between the normal operation (basic state) and the maintenance operation, the illumination at the inputs of the scanner 3i will usually change slightly. Accordingly, some components of the illumination system 19, for example, uniformity correction diaphragms, must be recalibrated. A die is typically not used to expose a single wafer 25i, but to expose a plurality of wafers, referred to as solder. A lot usually includes about 25 wafers 25i. For the exposure of such a solder usually up to 10 minutes are provided. Between lots takes place and a calibration of some components of the lighting system 19i instead. According to the invention, it is provided not to switch over during the exposure of a lot, but between the exposure of successive lots, between normal operation and maintenance operation. As a result, an additional calibration effort is avoided.

It was further recognized that the device according to the invention and the method according to the invention for supplying at least two groups of scanners 3i by means of a single FEL can also be advantageous for the general operation of a projection exposure system 1. With the device 28 according to the invention, it is possible, in particular, to distribute illumination radiation 5 from a single FEL 4 to two or more groups of scanners 3i, without this leading to a considerable reduction of the throughput. In particular, the device 28 enables a sequential, interval-wise supply of two or more groups of scanners 3i with illumination radiation 5 from a single FEL 4.

In this case, it is sufficient if the device 28 has a single input for illumination radiation 5. Of course, all of the embodiments described above can also be used with only a single FEL, as is the case anyway in the previously described maintenance condition.

Claims

claims:

1. A method for controlling a beam guiding device (28) for guiding a beam path of illumination radiation (5) in an illumination system (19) for a projection onsbelichtungssystem (1) with at least one radiation source (4i) and a plurality of scanners (3i) comprising at least an input for illumination radiation (5), at least two outputs for illumination radiation (5) and at least one beam guiding element (29i, 30i) which can be displaced by at least two displacement positions by means of a control device (35), wherein the illumination radiation (5) from at least one input depending on the displacement position of the first beam guiding element (29i) is steerable to different of the at least two outputs, characterized in that in an operating mode of the control device (35) a regular change of the assignment of the at least one input of the beam guiding device (28) on the ed The beam guiding device (28) has a period in which the ratio of the period of the change of the assignment of the at least one input of the beam guiding device (28) to the outputs of the beam guiding device (28) to an exposure time of one dies in the range from 1: 2 to 2 : 1 is.

2. The method according to claim 1, characterized in that the control device (35) has a further operating mode in which a constant assignment of a plurality of inputs of the beam guiding device (28) to the outputs of the beam guiding device (28) is predetermined.

3. Device (28) for guiding a beam path of illumination radiation (5) in an illumination system (19) for a projection exposure system (1) comprising at least one radiation source (4i) and a plurality of scanners (3i)

3.1. at least one entrance for illumination radiation (5),

3.2. at least two outputs for illumination radiation (5) and

3.3. at least one beam guiding element (2% 30i), which in each case can be displaced between at least two displacement positions,

3.4. wherein the illumination radiation (5) from at least one input in dependence on the displacement position of the first beam guiding element (29i) is steerable to different of the at least two outputs.

Device (28) according to claim 3, characterized in that it comprises at least two inputs for illumination radiation (5) and at least two beam guiding elements (2% 30i), which are displaceable between at least two displacement positions, wherein the illumination radiation (5) from the second input in dependence on the displacement position of the second beam guiding element (29i) is steerable to different of the at least two outputs.

5. Device (28) according to one of claims 3 or 4, characterized in that the at least one beam guiding element (29i) is displaceable controlled by means of a control device (35).

6. Device (28) according to one of claims 3 to 5, characterized in that the

Beam guide elements (2% 30i) are arranged in a first displacement position in each case outside the beam path of the illumination radiation (5). 7. Device (28) according to any one of claims 4 to 6, characterized in that in an arrangement of all the beam-guiding elements (2% 30i) in their first displacement position, all outputs simultaneously with illumination radiation (5) can be acted upon.

Device (28) according to one of claims 3 to 7, characterized in that the

Beam guiding elements (2% 30i) with a frequency of at least 1 Hz between their displacement positions are displaced.

Device (28) according to one of claims 3 to 8, characterized in that the

Beam guide elements (29i) each comprise at least one rotatably mounted mirror device.

10. Beam guiding element (29i) for spatially-temporally variable guidance of illumination radiation (5)

a. a plurality of curved reflection surfaces (33) having a radius of curvature,

b. wherein the beam guiding element (29i) is rotatably mounted about a rotation axis (31), and

c. wherein the radius of curvature of the reflection surfaces (33) in each case corresponds exactly to their distance from the axis of rotation (31).

11. illumination system (19) for a projection exposure system (1) comprising a plurality of scanners (3i)

11.1. at least one radiation source (4i) and

11.2. at least one device (18) according to one of claims 3 to 9.

12. illumination system (19) according to claim 11 for two groups of N scanners (3i to 3N, 3N + I to 3 ₂ N), characterized in that each scanner (3 ... 3N) of the one group a particular scanner (3 ₂ N + I ... 3 ₂ N) is assigned to the other group, wherein for each two associated scanner (3k, 3 ₂ N + ik; k = 1 ... N) of different groups a device (28) according to a of claims 3 to 9 is provided.

13. Illumination system (19) according to any one of claims 11 or 12, characterized in that the device (28) in each case in the beam path of the illumination radiation (5) is arranged behind a Auskoppeloptik (9).

14. Illumination system (19) according to claim 11, characterized in that the device (28) is arranged in the beam path of the illumination radiation (5) in front of a coupling-out optical system (9).

15. Illumination system (19) according to claim 11 or 14 with two radiation sources (4i), characterized in that each of the two radiation sources (4i) each have a group of scanners (3i) and a device (28) according to one of claims 3 to 9 associated is, wherein the assignment of the scanner (3i) of a group to one of the two radiation sources (4i) can be changed by means of the device (28).

Comprising a projection exposure system (1) for microlithography

16.1. an illumination system (19) according to any one of claims 11 to 15 and

16.2. a projection optical system (14) for projecting a reticle (22;) arranged in an object field (11) onto a wafer (25i) arranged in an image field (23i).

, A method of operating a projection exposure system (1) according to claim 16 comprising the following steps:

17.1. Determining a time period for an exposure of this,

17.2. Determining an amount of this to be exposed in the specific period of time,

17.3. Determining an assignment of the different dies to be exposed to the different scanners (3i), taking into account possibly different sizes of the dies,

17.5. Supplying all the scanners (3i) of the projection exposure system (1) with illumination radiation (5) from a single radiation source in the form of an FEL

(40,

17.6. wherein the illumination radiation (5) from this FEL (4i) by means of the at least one device (28) at intervals to different the scanner (3i) is deflected.

18. The method according to claim 17, characterized by the following steps:

18.1. Determining pairs of dies which differ in their sizes at most by a predetermined maximum value,

18.2. pairing the scanners (3i) for exposing wafers (25i) with each other of the previously determined pairs,

18.3. alternately exposing the dies of the previously determined pairs,

18.4. wherein, for alternately exposing this one, each of the beam guiding elements (29i) is displaced back and forth between the two displacement positions.

A method according to claim 17, characterized in that to determine the amount of N Dies to be exposed in the given period of time, one of the total of Dies N is selected such that a size difference between the largest of this dies and the smallest of these dies is less than a maximum size difference of all dies.

20. A method of servicing a projection exposure system (1) comprising all

Steps according to one of claims 17 to 19, characterized

20.1. the projection-projection system (1) has at least two radiation sources in the form of FEL (4i),

20.2. that the specified period is a maintenance period for one of the FELs

(4i), and

20.4. that one of the FELs (4i) is turned off for maintenance during the maintenance period, all the scanners (3i) of the projection exposure system (1) being supplied with illumination radiation (5) from the other of the FELs (4i), and the illuminating radiation (5) being from the other the FEL (4i) is deflected at intervals to different ones of the scanners (3i) by means of the at least one device (28).

21. A method of making a micro- or nanostructured device comprising the steps of:

21 1

21 .2

21 3

21 4

21 5