DE102021201026A1 - PROCEDURE FOR REPLACING A FIRST OPTICS MODULE FOR A SECOND OPTICS MODULE IN A LITHOGRAPHY SYSTEM - Google Patents

Abstract

A method is disclosed for exchanging a first optical module (202) for a second optical module (202 ') in a lithography system (100A, 100B), comprising the steps: a) attaching (S706) a measuring device (214) to the lithography system (100A) , 100B), b) measuring (S708) the actual position of the first optical module (202) with respect to the measuring device (214), c) dismantling (S712) the first optical module (202), and d) assembling (S714, S722) the second Optical module (202 ') as a function of the measured actual position of the first optical module (202).

Description

The present invention relates to a method for exchanging a first optical module for a second optical module in a lithography system.

Microlithography is used to manufacture microstructured components such as integrated circuits. The microlithography process is carried out with a lithography system which has an illumination system and a projection system. The image of a mask (reticle) illuminated by means of the illumination system is projected by means of the projection system onto a substrate, for example a silicon wafer, coated with a light-sensitive layer (photoresist) and arranged in the image plane of the projection system, in order to create the mask structure on the light-sensitive coating of the substrate transferred to.

The projection system, also referred to as a projection lens or POB (projection optics box), regularly comprises a plurality of mirrors and / or lenses. These optical elements sometimes have to be replaced. For example, it can happen that these become blind after a certain number of hours of operation of the lithography system. As a rule, entire optical modules that comprise a holding frame and the optical element held therein are exchanged. In contrast to the optical elements as such, which are sensitive, the optical modules are easy to handle.

When replacing, particularly in connection with non-actuated optical elements, the problem arises that the new optically effective surface must be positioned as identically as possible to the old optical surface. A subsequent correction, as is possible with activated optical elements, which are regularly adjustable in up to six degrees of freedom, can no longer be carried out after the new optical element has been installed.
Another problem is that there are hardly any highly accurate measuring instruments available at the operating site of the lithography system in order to control the position of the new optically effective surface and, if necessary, to correct it. For example, integrated circuits are manufactured at the operating site with the aid of the lithography system. High-precision measuring instruments are, in particular, coordinate measuring machines.

In addition, corresponding measurement reference surfaces on the projection lens in the assembled state of the lithography system, as is the case during operation, cannot be approached or are accessible for corresponding measuring instruments (such as coordinate measuring machines, for example).

Against this background, an object of the present invention is to provide an improved method for exchanging a first optical module for a second optical module in a lithography system.

1. a) Befestigen einer Messeinrichtung an der Lithographieanlage,
2. b) Vermessen der Ist-Position des ersten Optikmoduls bezüglich der Messeinrichtung,
3. c) Demontieren des ersten Optikmoduls, und
4. d) Montieren des zweiten Optikmoduls in Abhängigkeit der vermessenen Ist-Position des ersten Optikmoduls.

Accordingly, a method is proposed for exchanging a first optical module for a second optical module in a lithography system, with the following steps:

1. a) Attaching a measuring device to the lithography system,
2. b) measuring the actual position of the first optical module with respect to the measuring device,
3. c) dismantling the first optical module, and
4. d) mounting the second optical module as a function of the measured actual position of the first optical module.

As a result, the first (old) optical module and the second (new) optical module can advantageously be exchanged in such a way that the optically effective surface or the corresponding optical axis of the second optical module or its optical element are arranged at the same point or aligned in the same way as which was the case with the first optics module. This is possible with a relatively simple measuring technique, which can also be used in particular in a production facility such as a chip factory. A measurement on reference areas that can typically no longer be reached in the assembled state of the lithography system is also avoided.

An optical module preferably comprises a holding frame and an optical element held therein, such as a mirror, a lens, a lambda plate or an optical grating. In the simplest case, the optical module could also have only the optical element without a holding frame.

The terms “location”, “position” etc. always mean a position (in particular in x, y and / or z) and / or orientation (in particular in Rx, Ry and / or Rz, where “R” stands for the rotation around the respective axis is in space.

According to one embodiment, the first and second optics module each have a holding frame and an optical element mounted thereon with an optical axis, wherein in step b) the actual position of the holding frame of the first optics module with respect to the measuring device is measured and in step d) the second optics module is mounted as a function of the measured actual position of the holding frame of the first optical module.

Measuring on the holding frame is simple and can make use of reference areas that are already available for measuring the optically effective area (so-called fit measurement) of the optical element.

• Vermessen der Lage der optischen Achse bezüglich des Halterahmens im zweiten Optikmodul vor Schritt d),
• Bereitstellen von Messdaten betreffend die Lage der optischen Achse bezüglich des Halterahmens im ersten Optikmodul, und
• Montieren des zweiten Optikmoduls in Schritt d) in Abhängigkeit der vermessenen Ist-Position des Halterahmens des ersten Optikmoduls bezüglich der Messeinrichtung, der vermessenen Lage der optischen Achse im zweiten Optikmodul sowie der Messdaten.

According to a further embodiment, the method has:

• Measuring the position of the optical axis with respect to the holding frame in the second optical module before step d),
• Providing measurement data relating to the position of the optical axis with respect to the holding frame in the first optical module, and
• Mounting the second optical module in step d) as a function of the measured actual position of the holding frame of the first optical module with respect to the measuring device, the measured position of the optical axis in the second optical module and the measurement data.

With the help of the measurement data, the database is expanded and thus the alignment of the second optical module is more precise.

According to a further embodiment, the position of the second optical module, in particular the actual position of its holding frame, is measured with respect to the measuring device in step d), the mounting of the second optical module taking place as a function of the measured actual positions of the first and second optical modules.

This step also further improves the database for the correction or alignment of the second optical module.

According to a further embodiment, the actual position of the first optical module is determined in six degrees of freedom in step a), the mounting of the second optical module in step d) an alignment of the second optical module in six degrees of freedom depending on the actual position of the determined in six degrees of freedom includes first optical module.

The six degrees of freedom (three translational and three rotational) define the position of the first and second optical module in space.

According to a further embodiment, the mounting of the second optical module in step d) comprises aligning the second optical module using spacers.

The spacers include, for example, washers, plates, etc., in particular made of metal or ceramic.

According to a further embodiment, the alignment takes place using the spacers in a direction perpendicular to the main extension of an optically effective surface of the second optical module.

Spacers are particularly helpful in this direction. In particular in the horizontal direction, the second optics module can be aligned by knocking against the second optics module.

According to a further embodiment, a correction variable for correcting the actual position of the second optical module and the spacers required for this are determined in step d).

Determining the spacers may include determining their type, thickness (or other dimension), number, and so on.

According to a further embodiment, first and second spacers of different dimensions are provided and combined with one another in such a way that the corrected actual position is reached. Third, fourth, etc. spacers of different dimensions can also be provided.

As a result, a smaller number of spacers is required or minor adjustments (possibly machining) are required or fine gradations can thus be achieved over a large dimensional range.

According to a further embodiment, J first spacers and K second spacers are provided, the J first spacers differing from one another by a first, constant amount H1 and the K second spacers differing from one another by a second, constant amount H2, where K = H1 / H2.

Such spacers can be combined with one another over a large area, whereby the realizable distances are small (fine gradations are possible).

• Montieren des zweiten Optikmoduls in mithilfe von Grob-Abstandshaltern an der Lithographieanlage,
• Vermessen der Ist-Position des montierten, zweiten Optikmoduls bezüglich der Messeinrichtung,
• Ermitteln einer Korrekturgröße zur Korrektur der Ist-Position des zweiten Optikmoduls bezüglich der Messeinrichtung und der dafür erforderlichen Feinabstandshalter, wobei die Fein-Abstandshalter eine genauere Positionierung erlauben als die Grob-Abstandshalter,
• Demontieren des zweiten Optikmoduls von der Lithographieanlage, und
• Montieren des zweiten Optikmoduls mithilfe der Fein-Abstandshaltern an der Lithographieanlage.

According to a further embodiment it is provided:

• Mounting the second optical module on the lithography system using coarse spacers,
• Measurement of the actual position of the mounted, second optical module in relation to the measuring device,
• Determination of a correction variable for correcting the actual position of the second optical module with respect to the measuring device and the fine spacers required for it, the fine Spacers allow a more precise positioning than the coarse spacers,
• Dismantling the second optical module from the lithography system, and
• Mount the second optical module using the fine spacers on the lithography system.

Because a rough or prepositioning takes place first, the fine positioning can take place in a smaller tolerance window.

According to a further embodiment, the measuring device is releasably fastened, in particular screwed, to the lithography system, in particular on its sensor frame, in step a), and / or detached again from the lithography system after step d).

According to a further embodiment, the measuring device detects the actual position of the first optical module optically, in particular interferometrically, in step b).

According to a further embodiment, the first and second optical modules each have a mirror and / or these are mounted on an outside of the lithography system and / or its projection objective.

• Montieren des ersten Optikmoduls an der Lithographieanlage,
• Betreiben der Lithographieanlage, insbesondere zur Belichtung von Wafern, und
• Feststellen, dass ein Tausch des ersten Optikmoduls gegen das zweite Optikmodul erforderlich ist.

According to a further embodiment, step a) is preceded by the following steps:

• Mounting the first optical module on the lithography system,
• Operation of the lithography system, in particular for the exposure of wafers, and
• Determine that it is necessary to replace the first optics module with the second optics module.

In the present case, “a” is not necessarily to be understood as restricting to exactly one element. Rather, several elements, such as two, three or more, can also be provided. Any other counting word used here is also not to be understood to mean that there is a restriction to precisely the specified number of elements. Rather, numerical deviations upwards and downwards are possible, unless otherwise stated.

Further possible implementations of the invention also include combinations, not explicitly mentioned, of features or embodiments described above or below with regard to the exemplary embodiments. The person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.

• 1A zeigt eine schematische Ansicht einer Ausführungsform einer EUV-Lithographieanlage;
• 1B zeigt eine schematische Ansicht einer Ausführungsform einer DUV-Lithographieanlage;
• 2 zeigt in einem Vertikalschnitt schematisch und teilweise ein Projektionsobjektiv aus 1A sowie ein Optikmodul gemäß einer Ausführungsform;
• 3 zeigt ein Optikmodul mit seinem Halterahmen und darin gehaltenem Spiegel in perspektivische Ansicht gemäß einer Ausführungsform;
• 4 zeigt einen Prüfturm zur Vermessung eines optischen Elements des Optikmoduls aus 3 gemäß einer Ausführungsform;
• 5 und 6 zeigen jeweils Sätze von Abstandshaltern gemäß einer Ausführungsform; und
• 7 zeigt ein Flussdiagramm gemäß einer Ausführungsform.

Further advantageous configurations and aspects of the invention are the subject matter of the subclaims and of the exemplary embodiments of the invention described below. The invention is explained in more detail below on the basis of preferred embodiments with reference to the attached figures.

• 1A shows a schematic view of an embodiment of an EUV lithography system;
• 1B shows a schematic view of an embodiment of a DUV lithography system;
• 2 shows in a vertical section schematically and partially a projection lens from 1A and an optics module according to an embodiment;
• 3 shows an optical module with its holding frame and mirror held therein in a perspective view according to an embodiment;
• 4th shows a test tower for measuring an optical element of the optical module 3 according to one embodiment;
• 5 and 6th each show sets of spacers according to one embodiment; and
• 7th Figure 3 shows a flow diagram according to an embodiment.

In the figures, elements that are the same or have the same function have been given the same reference symbols, unless otherwise indicated. It should also be noted that the representations in the figures are not necessarily to scale.

1A shows a schematic view of an EUV lithography system 100A , which is a beam shaping and lighting system 102 and a projection system 104 includes. EUV stands for "extreme ultraviolet" (English: extreme ultraviolet, EUV) and describes a wavelength of work light between 0.1 nm and 30 nm. The beam shaping and lighting system 102 and the projection system 104 are each provided in a vacuum housing, not shown, each vacuum housing being evacuated with the aid of an evacuation device, not shown. The vacuum housings are surrounded by a machine room, not shown, in which drive devices are provided for mechanically moving or adjusting optical elements. Furthermore, electrical controls and the like can also be used in this machine room be provided. The EUV lithography system 100A has an EUV light source 106A on. As an EUV light source 106A For example, a plasma source (or a synchrotron) can be provided, which radiation 108A in the EUV range (extreme ultraviolet range), for example in the wavelength range from 5 nm to 20 nm. In the beam shaping and lighting system 102 becomes the EUV radiation 108A bundled and the desired operating wavelength from the EUV radiation 108A filtered out. The one from the EUV light source 106A generated EUV radiation 108A has a relatively low transmissivity through air, which is why the beam guidance spaces in the beam shaping and lighting system 102 and in the projection system 104 are evacuated.

This in 1A beam shaping and lighting system shown 102 has five mirrors 110 , 112 , 114 , 116 , 118 on. After going through the beam shaping and lighting system 102 becomes the EUV radiation 108A on a photo mask (Engl .: reticle) 120 directed. The photo mask 120 is also designed as a reflective optical element and can be used outside of the systems 102 , 104 be arranged. The EUV radiation can continue 108A by means of a mirror 122 on the photo mask 120 be steered. The photo mask 120 has a structure which, by means of the projection system 104 scaled down to a wafer 124 or the like is mapped.

The projection system 104 (also known as a projection lens) has six mirrors M1 until M6 for imaging the photomask 120 on the wafer 124 on. Individual mirrors can do this M1 until M6 of the projection system 104 symmetrical about an optical axis 126 of the projection system 104 be arranged. It should be noted that the number of mirrors M1 until M6 the EUV lithography system 100A is not limited to the number shown. More or fewer mirrors than M1 to M6 can also be provided. Furthermore are the mirrors M1 until M6 usually curved on their front side for beam shaping.

1B shows a schematic view of a DUV lithography system 100B , which is a beam shaping and lighting system 102 and a projection system 104 includes. DUV stands for "deep ultraviolet" (English: deep ultraviolet, DUV) and describes a wavelength of work light between 30 nm and 250 nm.

The DUV lithography system 100B has a DUV light source 106B on. As a DUV light source 106B For example, an ArF excimer laser can be provided, which radiation 108B emitted in the DUV range at 193 nm, for example.

This in 1B beam shaping and lighting system shown 102 directs the DUV radiation 108B on a photo mask 120 . The photo mask 120 is designed as a transmissive optical element and can be used outside of the systems 102 , 104 be arranged. The photo mask 120 has a structure which, by means of the projection system 104 scaled down to a wafer 124 or the like is mapped.

The projection system 104 has multiple lenses 128 and / or mirror 130 for imaging the photomask 120 on the wafer 124 on. You can use individual lenses 128 and / or mirror 130 of the projection system 104 symmetrical about an optical axis 126 of the projection system 104 be arranged. It should be noted that the number of lenses 128 and mirror 130 the DUV lithography system 100B is not limited to the number shown. There can also be more or fewer lenses 128 and / or mirror 130 be provided. Furthermore are the mirrors 130 usually curved on their front side for beam shaping.

An air gap between the last lens 128 and the wafer 124 can through a liquid medium 132 be replaced, which has a refractive index> 1. The liquid medium 132 can be ultrapure water, for example. Such a structure is also referred to as immersion lithography and has an increased photolithographic resolution. The medium 132 can also be referred to as immersion liquid.

2 shows in a vertical section schematically and partially the projection objective 104 the end 1A , in an area that the mirror M5 includes. The mirror M5 is in a holding frame 200 (Engl .: mirror support frame) held with which he an optical module 202 forms. The holding frame 200 attached the mirror M5 on a support frame 204 of the projection lens 104 . On the support frame 204 are also the others, in 2 mirror not shown M1 - M4 and M6 attached.

The mirror M5 In contrast to one or more of the other mirrors, it is intended to be non-actuatable. That is, its optically effective area 206 can after installing the optics module 202 in the projection lens 104 can no longer be adjusted with the aid of actuators such as Lorenz actuators. The installation of the optics module 202 is usually done using screws that attach it to the support frame 204 is screwed. In this case, spacers, in particular washers (shims or spacers), can be placed underneath around a predefined setpoint position of the optical axis 208 of the mirror M5 to reach. The mirror M5 again, in contrast to other mirrors, has an installation situation in which it can be seen from outside the Projection lens 104 is accessible and can therefore be replaced if necessary. Such a case of need arises, for example, when the mirror M5 went blind and / or has gone through a predefined number of exposures or operating hours.

• Bereits vor der Erstmontage des Projektionsobjektivs 104 wird das (alte) Optikmodul 202 vermessen. Dazu wird zunächst die optische Achse 208 des Spiegels M5 vermessen (auch als Passemessung bezeichnet). In 3 ist das Optikmodul 202 mit seinem Halterahmen 200 und darin gehaltenem Spiegel M5 in perspektivische Ansicht gezeigt. Um die optisch wirksame Fläche 206 (Engl.: optical footprint) herum sind Referenzflächen 300 angeordnet. Die Lage der optischen Achse 208 wird in Bezug auf diese Referenzflächen (zwei dieser vorzugsweise sechs Referenzflächen sind beispielhaft mit 300 bezeichnet) gemessen, und zwar in allen sechs Freiheitsgraden (drei translatorische und drei rotatorische Freiheitsgrade). Dies kann beispielsweise in einem in 4 schematisch in Seitenansicht gezeigten Prüfturm 400 optisch, insbesondere mittels eines Interferometers 402, erfolgen.

Will be the old or first optical module 202 against a new or second optics module 202 ' exchanged, as indicated by the double arrow in 2 indicated, must in particular because of the lack of actuation of the mirror M5 ensure that the optical axis 208 ' of the new M5 'when installed, identical or almost identical to the optical axis 208 of the old M5 is positioned and aligned in the previously installed state. This is achieved according to the following exemplary embodiment as follows:

• Even before the first assembly of the projection lens 104 becomes the (old) optics module 202 measured. To do this, first the optical axis 208 of the mirror M5 measure (also known as pass measurement). In 3 is the optics module 202 with its holding frame 200 and mirror held in it M5 shown in perspective view. Around the optically effective area 206 (English: optical footprint) around are reference areas 300 arranged. The position of the optical axis 208 is measured in relation to these reference surfaces (two of these, preferably six, reference surfaces are designated by 300 as an example), specifically in all six degrees of freedom (three translational and three rotational degrees of freedom). For example, this can be done in an in 4th test tower shown schematically in side view 400 optically, in particular by means of an interferometer 402 , take place.

Then the mirror M5 in the holding frame 200 built-in. Also the holding frame 200 has in particular six reference surfaces, two of which are exemplified with the reference number 302 are designated. The next step is the position of the mirror M5 relative to the holding frame 200 measured. For this purpose, a coordinate measuring machine, in particular, can use the reference surfaces 300 and 302 approach one after the other (also referred to as CMM measurement), although other measurement methods are also possible. Thus, the position of the optical axis is now 208 in relation to the reference areas 302 on the holding frame 200 determined.

Ultimately, the procedure used or the measurement method used do not play a major role. It is only important that the position of the optical axis 208 in relation to the holding frame 200 or its reference areas 302 is determined exactly (step S700 in 7th ). The corresponding measurement data - hereinafter collectively as measurement data M5_alt - can be stored in a data memory and made available for later use (explained in more detail below).

Returning to 2 - on the in 7th The exemplary flowchart shown is also referred to below - the optics module is now 202 on the support frame 204 of the projection lens 104 aligned and secured (S702 in 7th ), especially screwed on. Corresponding screws are labeled 210.

The alignment is done in such a way that the optical axis 208 assumes a target position, which was calculated and defined in advance, so that the mirror M5 suitable with the other mirrors of the projection system 104 interacts. The alignment takes place as a function of the previously measured position of the optical axis 208 in relation to the holding frame 200 or its reference areas 302 (please refer 3 ). In addition, the location of the reference surfaces 302 at the holding room 200 relative to reference surfaces 211 (one is in 2 shown as an example) on a sensor frame 216 of the projection lens 104 recorded. The reference areas 302 are at this time of assembling the projection lens 104 still accessible, not later, as explained in more detail below. The sensor frame 216 is the frame, which of the support frame 204 is mechanically decoupled and carries sensors, with the help of which in particular the position of one or more mirrors on the support frame 204 are attached, is recorded. The sensor frame 216 forms the spatial reference system of the projection lens 104 . The sensor frame 216 surrounds the support frame according to the embodiment 204 at least partially.

Thus, the actual position of the optical axis 208 in relation to the sensor frame 216 detected and with the target position of the optical axis 208 be compared. For the purpose of aligning the target and actual position of the optical axis 208 becomes the position of the optics module 202 using spacers 212 corrected, which can in particular be washers. The spacers 212 can be provided with a standard dimension and machined until a target dimension is reached, around the target position of the optical axis 208 to achieve.

Then the lithography system 100A including the projection lens 104 put into operation ( S704 in 7th ), for example at a manufacturer of microchips. After a certain number of exposures and / or hours of operation, the mirror has M5 its EOL (End-of-Life) has been reached and must be exchanged for a new one. For example, the mirror M5 be (partially) blind at this point.

As in 2 Also shown is a measuring device 214 on the sensor frame 216 of the projection lens 104 attached (S706 in 7th ), especially screwed on before the (old) optics module 202 from the support frame 204 is dismantled. Corresponding screws are marked with the reference number 218 designated. The measuring device 214 can be designed as an optical measuring device, in particular an interferometer.

With the help of the measuring device 214 becomes the actual position of the (old) optics module 202 in relation to the same (the measuring device 214 serves as a reference) measured ( S708 in 7th ), in all six degrees of freedom. This includes, in particular, a measurement of the distance between the measuring device 214 and the optics module 202 in the z-direction. This is in 2 denoted by z and means the direction essentially perpendicular to the main extension plane of the optically effective surface 206 of the mirror M5 . Alternatively, the Z direction means the vertical direction, i.e. in or against gravity. The measuring device measures in the horizontal plane 214 the distance in x-direction (in 2 shown) and y-direction (perpendicular to the plane of the paper, in 2 Not shown). As a reference on the optics module 202 can in turn its reference surfaces 302 (please refer 3 ) to serve. The distances determined in this way - hereinafter collectively as measurement data A_alt - are in particular stored in a data memory.

After that, the (old) optics module 202 from the support frame 204 dismantled ( S712 in 7th ), but not the measuring device 214 . This remains exactly in place as it serves as a reference for measuring the (new) optics module 202 ' is used (step S716 below).

Before the (old) optical module 20 is dismantled, parallel to it or afterwards, the position of the optical axis 208 ' of the mirror M5 ' of the (new) optics module 202 ' relative to reference surfaces 302 ' on its holding frame 200 ' measured ( S710 in 7th ). This happens in connection with the initial assembly of the (old) optics module 202 manner described above. So it is first the position of the optical axis 208 ' in relation to reference areas 300 ' and then the position of the reference surfaces 300 in relation to reference areas 302 ' of the holding frame 200 ' measured. These measurement data, too - hereinafter referred to as measurement data M5_new - are in particular stored in a storage device.

In a further step, the (new) optics module 202 ' on the support frame 204 - as part of a rough positioning - aligned and fixed ( S714 in 7th ), especially screwed. As a first approximation, the alignment is carried out using coarse spacers, which can also be referred to as standard spacers. When selecting the coarse spacers, the measurement data A_alt or the measurement data M5_alt and or M5_new must be taken into account.

In the next step ( S716 in 7th ) becomes the actual position of the (new) optics module 202 ' using the measuring device 214 and measured with respect to the same. Here again the distances (as in connection with the old optics module 202 explained) and in the form of measurement data A_new saved.

Below ( S718 in 7th ) becomes a correction variable for correcting the alignment of the optics module 202 ' taking into account the measurement data A_new , A_alt , M5_alt , M5_new determined. This can in particular take place in an automated manner on a computer device such as a microprocessor. Suitable fine spacers are determined by means of the correction variable. The fine spacers allow a more precise alignment of the optics module 202 ' than the coarse spacers too.

The optics module 202 ' will be in a further step ( S720 in 7th ) from the support frame 204 dismantled and then reassembled on this using the fine spacers ( S722 in 7th ). The optical axis is correspondingly correct 208 ' of the (new) optics module 202 ' with the optical axis 208 of the (old) optics module 202 match.

In particular, the step of rough positioning ( S714 ) is optional. Also the explanations regarding the mirror M5 are by no means to be understood as restrictive. Ultimately, the described method can also be applied to any other optical element - including, for example, the exposure system 102 - be applied.

the 5 and 6th illustrate embodiments of each set of Fein spacers 500 , 600 for use in the assembly step described above ( S722 ).

The in 5 The set shown includes a number J , for example 20, different spacers 500 . The first spacer 500 In this sentence, a thickness measure (in particular in the z-direction in the assembled state) in the form of a base thickness BD1 on. The second spacer 500 shows the base thickness as the thickness measure BD1 + a first constant measure H1 , the third the base thickness BD1 + 2 × H1, the fourth the base thickness BD1 + 3 × H1 etc. BD1 is, for example, 7 mm, H1 30 µm.

The in 6th shown set includes a number K different spacers 600 . The thickness dimension for the first spacer is the basic thickness here BD2 . The second spacer has the base thickness as the thickness dimension BD2 + a first constant measure H2 , the third the base thickness BD1 + 2 × H2, the fourth the base thickness BD1 + 3 × H2 etc. The number K is now chosen so that K = H1 / H2. BD2 is for example 2 mm, H2 2 µm. This results in the value 15 for K.

The spacers can thus be advantageous 500 , 600 combine in such a way that every dimension can be provided at intervals of 2 µm over several hundred µm.

The spacers 500 , 600 each have, for example, an unspecified hole for the screws to pass through 212 (please refer 2 ) on.

Although the present invention has been described on the basis of exemplary embodiments, it can be modified in many ways.

List of reference symbols

100A

EUV lithography system

100B

DUV lithography system

102

Beam shaping and lighting system

104

Projection system

106A

EUV light source

106B

DUV light source

108A

EUV radiation

108B

DUV radiation

110

mirrors

112

mirrors

114

mirrors

116

mirrors

118

mirrors

120

Photomask

122

mirrors

124

Wafer

126

optical axis

128

lens

130

mirrors

132

medium

200,200 '

Holding frame

202, 202 '

Optics module

204

Support frame

206, 206 '

optically effective area

208, 208 '

optical axis

210

screw

211

Reference area

212

Spacers

214

Measuring device

216

Sensor frame

218

screw

300, 300 '

Reference area

302, 302 '

Reference area

400

Test tower

402

Interferometer

500,600

Spacers

A_alt

Measurement data

A_new

Measurement data

BD1, BD2

Base thickness

H1, H2

Measure

J, K

number

M1

mirrors

M2

mirrors

M3

mirrors

M4

mirrors

M5, M5 '

mirrors

M5_alt

Measurement data

M5_new

Measurement data

M6

mirrors

S700 - S722

steps

Claims (15)

Method for exchanging a first optical module (202) for a second optical module (202 ') in a lithography system (100A, 100B), comprising the steps: a) attaching (S706) a measuring device (214) to the lithography system (100A, 100B), b) measuring (S708) the actual position of the first optical module (202) with respect to the measuring device (214), c) dismantling (S712) the first optical module (202), and d) mounting (S714, S722) the second optical module (202 ') as a function of the measured actual position of the first optical module (202). Procedure according to Claim 1 , wherein the first and second optical modules (202, 202 ') each have a holding frame (200, 200') and an optical element (M5, M5 ') with an optical axis (208, 208') mounted thereon, wherein in step b ) measure the actual position of the holding frame (200) of the first optics module (202) with respect to the measuring device (214) and in step d) the second optics module (202 ') as a function of the measured actual position of the holding frame (200) of the first optics module (202) is mounted. Procedure according to Claim 2 , further comprising: measuring (710) the position of the optical axis (208 ') with respect to the holding frame (200') in the second optical module (202 ') before step d), providing (S700) of measurement data (M5_alt) regarding the position of the optical Axis (208) with respect to the holding frame (200) in the first optics module (202), and mounting (714) the second optics module (202 ') in step d) as a function of the measured actual position of the holding frame (200) of the first optics module (202 ) with regard to the measuring device (214), the measured position of the optical axis (208 ') in the second optical module (202') and the measurement data (M5_alt). Method according to one of the Claims 1 - 3 , wherein in step d) the position of the second optical module (202 '), in particular the actual position of its holding frame (200'), is measured with respect to the measuring device (214), the mounting of the second optical module (202 ') being a function of the measured actual positions of the first and second optical module (202, 202 ') takes place. Method according to one of the Claims 1 - 4th , wherein in step a) the actual position of the first optical module (202) is determined in six degrees of freedom, and the mounting of the second optical module (202 ') in step d) an alignment of the second optical module (202') in six degrees of freedom as a function of the actual position of the first optical module (202) determined in six degrees of freedom. Method according to one of the Claims 1 - 5 wherein mounting the second optical module (202 ') in step d) comprises aligning the second optical module (202') using spacers (212, 500, 600). Procedure according to Claim 6 wherein the alignment is carried out using the spacers (212, 500, 600) in a direction (z) perpendicular to the main extension of an optically effective surface (206 ') of the second optical module (206). Procedure according to Claim 6 or 7th , wherein in step d) a correction variable for correcting the actual position of the second optical module (202 ') and the spacers (212, 500, 600) required for this are determined (S718). Procedure according to Claim 8 , wherein first and second spacers (212, 500, 600) of different dimensions (H1, H2) are provided and combined with one another in such a way that the corrected actual position is reached. Procedure according to Claim 9 , wherein J first spacers (500) and K second spacers (600) are provided, wherein the J first spacers (500) differ from one another in a first, constant amount H1 and the K second spacers (600) differ in a second, constant Differentiate dimension H2, where K = H1 / H2. Method according to one of the Claims 1 - 10 , wherein step d) comprises: mounting (S714) the second optical module (202 ') with the aid of coarse spacers on the lithography system (100A, 100B), measuring (S716) the actual position of the mounted, second optical module (202') with respect to the measuring device (214), determining (S718) a correction variable for correcting the actual position of the second optical module (202 ') with respect to the measuring device (214) and the fine spacers (212, 500, 600) required for this, the fine spacers (212, 500, 600) allow a more precise positioning than the coarse spacers, dismantling (S720) the second optical module (202 ') from the lithography system (100A, 100B), and mounting (722) the second optical module (202') with the help of the fine spacers (212, 500, 600) on the lithography system (100A, 100B). Method according to one of the Claims 1 - 11 , the measuring device (214) being releasably attached, in particular screwed, to the lithography system (100A, 100B), in particular to its sensor frame (216), and / or being released again from the lithography system (100A, 100B) after step d) . Method according to one of the Claims 1 - 12th wherein the measuring device (214) in step b) records the actual position of the first and / or second optical module (202) optically, in particular interferometrically. Method according to one of the Claims 1 - 13th , wherein the first and second optical modules (202, 202 ') each have a mirror (M5, M5') and / or are mounted on an outside of the lithography system (100A, 100B) and / or its projection objective (104). Method according to one of the Claims 1 - 14th , whereby step a) is preceded by the following steps: Mounting (S702) the first optical module (202) on the lithography system (100A, 100B), operating (S704) the lithography system (100A, 100B), in particular for exposing wafers (124), and determining that an exchange of the first optical module ( 202) against the second optical module (202 ') is required.

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