DE102018201320A1 - Method for tempering a component - Google Patents

Abstract

The invention relates to a method for tempering a component, wherein this component between a first system and a second system is convertible. According to one aspect, the method comprises the steps of determining a temperature drift of a temperature of the component (131) to be expected after transferring the component (131) from the first system (110) to the second system (120), and modifying one in the first System (110) existing temperature and / or one in the second system (120) existing temperature such that the actual after passing the component (131) from the first system (110) in the second system (120) adjusting temperature drift over the expected temperature drift is reduced.

Description

BACKGROUND OF THE INVENTION

Field of the invention

The invention relates to a method for tempering a component, wherein this component between a first system and a second system is convertible. The invention can be advantageously implemented in particular in applications in which a temperature-sensitive component is regulated to a reference temperature which is as constant as possible or the problem of temperature drifts when transferring the component into different systems or compartments is to be avoided or at least reduced.

State of the art

Microlithography is used to fabricate microstructured devices such as integrated circuits or LCDs. The microlithography process is carried out in a so-called projection exposure apparatus which has an illumination device and a projection objective. The image of a mask (= reticle) illuminated by means of the illumination device is hereby projected onto a substrate (eg a silicon wafer) coated with a photosensitive layer (photoresist) and arranged in the image plane of the projection objective in order to apply the mask structure to the photosensitive coating of the Transfer substrate.

In EUV projected projection lenses, i. at wavelengths of e.g. about 13 nm or about 7 nm, mirrors are used as optical components for the imaging process, due to the lack of availability of suitable translucent refractive materials.

A practice in the use of alternating components, e.g. In such measuring method occurring problem is that there is a high sensitivity of the measurement results in terms of temperature changes, to achieve the required measurement accuracy is to require a temperature to a few millikelvin. The realization of such an exact tempering again represents a demanding challenge in practice. One reason for this is that usually a change component used for a current measuring operation is taken from a separate magazine accommodating a plurality of different change components and into the actual measuring system or a measuring system accommodating housing is transferred, with a corresponding thermal adaptation of the systems concerned (magazine on the one hand and measuring system on the other hand) by the both sides existing and possibly also temporal variations subject to thermal loads difficult.

In addition, even after the transfer of the respective change component into the measuring system, its approximation to a respective target temperature typically takes place over a period of several hours due to the relevant time constant, with the result that a comparatively long period of time is required until a sufficiently high temperature stability is achieved the relevant exchange component is reached.

However, insufficient temperature stability of the alternating component has undesirable changes in optical properties, e.g. thermally induced refractive index variations as well as mechanical drift effects in the measurement setup and thus ultimately a defectiveness of the measurement result.

Impairments in the temperature stability of the AC component and the attendant problems described above can in practice further result from the fact that the AC component is typically exposed to thermal loads during its transfer into the measurement system (i.e., on the way there). Such thermal loads can only be assumed as examples of motors used for transfer (which can be arranged, for example, on a gripper arm used to handle the changeover component), but also on other components in the vicinity of the respective transport path. The change in the thermal state of the alternating component caused by the respective thermal loads may include heating and / or cooling, whereby these effects may also occur differently over the entire volume of the alternating component depending on the relative position of the thermal loads.

The prior art is merely an example EP 1 531 364 B1 directed.

SUMMARY OF THE INVENTION

Against the above background, it is an object of the present invention to provide a method for controlling the temperature of a component, wherein when transferring the component between a first system and a second system, temperature drifts are reduced and the associated problems described above are at least largely avoided.

This object is solved by the features of the independent claims.

• - Ermitteln eines nach Überführen der Komponente von dem ersten System in das zweite System zu erwartenden Temperaturdrifts einer Temperatur der Komponente; und
• - Modifizieren einer in dem ersten System vorhandenen Temperatur und/oder einer in dem zweiten System vorhandenen Temperatur derart, dass der sich nach Überführen der Komponente von dem ersten System in das zweite System tatsächlich einstellende Temperaturdrift gegenüber dem zu erwartenden Temperaturdrift reduziert wird.

According to one aspect, a method according to the invention for controlling the temperature of a component, which component can be transferred between a first system and a second system, comprises the following steps:

• Determining a temperature drift of a temperature of the component to be expected after transfer of the component from the first system to the second system; and
• Modifying a temperature present in the first system and / or a temperature present in the second system in such a way that the temperature drift actually occurring after the component has been transferred from the first system to the second system is reduced compared to the expected temperature drift.

The invention is based in particular on the concept, for controlling a temperature controllable between a first and a second system component not both systems under specification of identical temperature setpoints (ie, for example, the cooling systems associated with these systems to supply cooling water of the same temperature), but first determine the temperature drift expected after transferring the component from the first system to the second system and, based thereon, modify the temperature in at least one of the two systems.

Both with regard to the determination of the expected temperature drift and the subsequent modification of the temperature present in the first system and / or the second system, different strategies are possible according to the invention as described in more detail below.

In one embodiment, temperature measurements may be taken using a sensor attached to the component before and / or after the component is transferred from the first system to the second system. Alternatively or additionally, it is also possible to measure a temperature currently present in the first system and / or a temperature currently present in the second system. Furthermore, (optionally also in combination with the aforementioned embodiments) a predictive model for predicting a temporal evolution of the temperature of the component after transferring the component from the first system to the second system can be set up.

As regards the step of modifying a temperature present in the first system and / or a temperature present in the second system, this step may be modified by modifying the setpoint of a corresponding temperature control, alternatively or additionally by modifying the operation of at least one in the first System and / or in the second system existing component (with a corresponding change of the relevant thermal load).

• - Ermitteln einer auf dem Weg von dem ersten System zum zweiten System zu erwartenden Änderung des thermischen Zustandes der Komponente; und
• - Temperieren der Komponente vor dem Überführen in das zweite System derart, dass diese zu erwartende Änderung wenigstens teilweise kompensiert wird.

According to one embodiment, the method further comprises the steps:

• Determining a change in the thermal state of the component to be expected on the way from the first system to the second system; and
• - Temperieren the component before transferring to the second system such that this expected change is at least partially compensated.

• - Ermitteln einer auf dem Weg von dem ersten System zum zweiten System zu erwartenden Änderung des thermischen Zustandes der Komponente; und
• - Temperieren der Komponente vor dem Überführen zum zweiten System derart, dass diese zu erwartende Änderung wenigstens teilweise kompensiert wird.

The invention further relates to a method for tempering a component, wherein this component is convertible between a first system and a second system, the method comprising the following steps:

• Determining a change in the thermal state of the component to be expected on the way from the first system to the second system; and
• - Temperieren the component before transferring to the second system such that this expected change is at least partially compensated.

According to one embodiment, before the temperature control, the component is transferred into a region separated from at least one further component located in the first system.

According to one embodiment, the determination of a change in the thermal state of the component to be expected on the way from the first system to the second system is carried out by simulation and / or measurement of the influence of thermal loads which the component is on its way from the first system to the second system is exposed.

In embodiments of the invention, the component has an optical component, in particular an optical component which is adapted to a specimen geometry. The wording "adaptation to a specimen geometry" is to be understood in particular as meaning that, for example, in a compensation optics when changing the specimen or for measuring a specimen with a different geometry or topography, the relevant (optical alternating) component is also changed. For example, it may be in the optical Change component to act around a calibration, with a change between calibration mirrors of different radii of curvature and diameter depending on the test specimen to be measured.

However, the invention is not limited to this, but in principle can also be implemented advantageously in other applications in which a temperature-sensitive component is regulated to a constant reference temperature or the problem of temperature drifts when transferring the component into different systems or compartments should be avoided or at least reduced ,

Further embodiments of the invention are described in the description and the dependent claims.

The invention will be explained in more detail with reference to embodiments shown in the accompanying drawings.

list of figures

• 1-5 schematische Darstellungen zur Erläuterung beispielhafter Ausführungsformen der vorliegenden Erfindung; und
• 6 eine schematische Darstellung einer für den Betrieb im EUV ausgelegten Projektionsbelichtungsanlage.

Show it:

• 1-5 schematic representations for explaining exemplary embodiments of the present invention; and
• 6 a schematic representation of a designed for operation in the EUV projection exposure system.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

6 shows first a schematic representation of an exemplary projected for operation in the EUV projection exposure system.

According to 6 has a lighting device in a designed for EUV projection exposure system 10 a field facet mirror 3 and a pupil facet mirror 4 on. On the field facet mirror 3 becomes the light of a light source unit, which is a plasma light source 1 and a collector mirror 2 includes, steered. In the light path after the pupil facet mirror 4 are a first telescope mirror 5 and a second telescope mirror 6 arranged. In the light path below is a deflection mirror 7 arranged, which reflects the radiation impinging on an object field in the object plane of a six mirror 21 - 26 comprehensive projection lens steers. At the location of the object field is a reflective structure-bearing mask 31 on a mask table 30 arranged, which is imaged by means of the projection lens in an image plane in which a substrate coated with a photosensitive layer (photoresist) 41 on a wafer table 40 located.

The mirror tested in the context of the invention can be, for example, any mirror of the projection exposure apparatus 10 for example the mirrors 21 or 22 the projection lens or the mirror 7 the lighting device, act.

1 shows a merely schematic representation to illustrate a possible scenario in which the inventive method can be realized.

In this embodiment, it is a component to be tempered according to the invention 131 a matched to the specimen geometry optical component change. According to 1 is this component with a plurality of other components (of which, for the sake of simplicity, only two components 132 and 133 drawn in) in a magazine 110 arranged. With " 120 "Is a (in a corresponding housing 121 accommodated) measuring arrangement for testing a mirror, in particular a mirror of a microlithographic projection exposure apparatus. With " 140 "Are merely indicated heat loads in both the first system 110 forming magazine as well as in the second system 120 designating measuring arrangement. As indicated by the double arrow in 1 in each case one of the components is indicated for use for the interferometric measurement 131 . 132 . 133 , ... in the measuring arrangement or the second system 120 transferred.

In order to minimize temperature drift effects and concomitant impairment of the measurement accuracy in the interferometric measurement, different embodiments are described below. These embodiments have in common that not both systems 110 . 120 be controlled from the outset only to the same temperature setpoint, but rather first after transferring the respective component of the first system 110 in the second system 120 expected temperature drift determined and then one in the first system 110 existing temperature and / or one in the second system 120 existing temperature is modified depending on this expected temperature drift.

According to a first (in the flow chart of 2 described) embodiment can directly on the relevant component 131 (or. 132 . 133 , ...) a temperature sensor be mounted, via which with appropriate temperature measurements before or after transfer of the component from the first system 110 in the second system 120 (Steps S21 and S22 ) a corresponding temperature offset value is obtained. This temperature offset value can in turn be used as the basis for the modification of the first system 110 or the second system 120 existing temperature can be used (step S23 ). What the last-mentioned modification of the temperature in the first system 110 and / or the second system 120 This modification may include modifying the setpoint of a corresponding temperature control and / or modifying the operation of at least one component present in the system (ie, changing a corresponding thermal load).

According to another (in the flow chart of 3 described) embodiment, the determination of the after transfer of the component 131 (or. 132 . 133 , ...) from the first system 110 in the second system 120 expected temperature drifts of the relevant component 131 also using in the respective system 110 or. 120 existing stationary temperature sensors (in 1 With " 150 "Denoted"), so that in each case in the first system 110 currently available temperature and in the second system 120 currently available temperature can be measured (steps S31 and S32 ). Based on these measurements, which in further embodiments also in combination with temperature measurements using a sensor attached to the respective component according to 2 can be performed again, as described above, a modification of the in the first system 110 and / or in the second system 120 existing temperature.

In a further embodiment (which, in turn, in combination with one or both of the above with reference to 2 and 3 described embodiments) is carried out according to the invention (as in the flowchart of 4 described) establishing a predictive model for predicting a temporal evolution of the temperature of the component in question 131 (or. 132 . 133 , ...) after transferring from the first system 110 in the second system 120 (Step S41 In turn, this predictive model forms the basis for the modification of the first system as described above 110 and / or in the second system 120 existing temperature (step S42 ) is used.

The predictive model can be set up based on experimental data (eg regarding the temporal behavior of the measuring arrangement or of the housing accommodating the latter as a function of the measurements carried out with the measuring arrangement) and / or based on theoretical analyzes. If necessary, measurement signals of further sensors, for example with regard to the temperature in the environment or in the clean room and / or the temperature of the housing wall or of the housing receiving the measuring arrangement, can also be taken into account when setting up the model. Furthermore, in the design of the model, the fact that different positions of the components in the first system or magazine due to the different proximity to the existing thermal loads to different offset values after transferring the component from the first system 110 in the second system 120 being able to lead. In this way, for example, a modification of the temperature in the first system which subsequently takes place in the method according to the invention can always be carried out in such a way that a temperature drift is reduced or minimized for the component to be transferred next to the second system.

In a further embodiment, the embodiments or steps described above can also be combined as follows:

In a first stage, first analogous to 2 with appropriate temperature measurements using one directly on the component in question 131 (or. 132 . 133 , ...) mounted temperature sensor before or after transfer of the component 131 from the first system 110 in the second system 120 (Steps S21 and S22 ) a corresponding temperature offset value can be determined, whereupon a (first) modification of that in the first system 110 or the second system 120 existing temperature (step S23 ) is made.

Subsequently, the temperature of the relevant, in the second system 120 transferred component 131 using the on this component 131 attached temperature sensor continues to be measured or monitored and as a basis for a continuous adjustment of the in the first system 120 existing temperature can be used. In this case, if appropriate, on a comparatively short time scale occurring temperature changes, which take place in the first and / or second system and according to 3 (Steps S31 and S32 ) can be taken into account.

Finally, on the basis of the data obtained in the above steps - and possibly further data on the measuring activities of the measuring arrangement - a predictive model can be set up, with this model the further temporal evolution of the temperature of a current or future used in the measuring arrangement (alternating ) Component and again as a basis for modifying that in the first system 110 and / or in the second system 120 existing temperature can be.

In another, referring to below 5 described and realized both in combination with and independently of the embodiments described above embodiment, thermal loads can be considered according to the invention, which the component 131 during the transfer to the second system 120 (ie on the way there) is exposed. This may only be by way of example heat loads, which from one to one for the transfer of the component 131 go out of the gripper arm located motor. Furthermore, it may also be any other thermal loads that the component 131 on the way to the second system 120 temporarily suspended.

According to 5 takes place in a first step S51 First, the determination of a component during the transfer 131 from the first system 110 to the second system 120 expected thermal change. This determination can - with appropriate knowledge of the relevant heat loads - done by means of a simulation or in an advance measurement or calibration.

In the case of determination via measurement or calibration, instead of the component 131 first a calibration component of the first system 110 to the second system 120 be transferred, with appropriate (eg on the calibration itself or a corresponding version) provided temperature sensors spatially resolved, the heating or cooling can be measured.

According to 5 takes place in an optional further step S52 a transfer of the still in the first system 110 located component 131 in another area, which to avoid unwanted thermal influence or disturbance of the other components 132 . 133 , ... in the first system of these components 132 . 133 , ... is further away, whereby this other area either also in the first system 110 or outside of it.

Subsequently, in the step S53 a tempering of the component 131 to compensate for in step S51 determined during the transfer to the second system 120 expected thermal change. For this purpose, by way of example only one or more heating or cooling elements can be used (eg heating or cooling plates, Peltier elements etc.), which, for example, into the surrounding area of the component 131 retracted or already exist there. Optionally, said heating or cooling elements can also be spatially resolved (ie via the surface or the volume of the component 131 varying) a warming or cooling of the component 131 can be made. Also optionally, one or more heat shields may be in the area between the component 131 and the other components 132 . 133 , ... in the first system 110 to further minimize thermal interference or disturbance of these other components 132 . 133 , ... are retracted.

In case of a step S53 desired, localized temperature control of the component 131 (with which eg one on the way to the second system 120 expected localized heating or cooling of the component 131 Account should be taken) is preferably the temperature in step S53 only immediately before the start of the transfer to the second system 120 to otherwise possibly by heat conduction taking place in the meantime temperature compensation within the component 131 to avoid.

Finally, in the step S54 the transfer of the component 131 in the second system 120 , If appropriate, previously in the step S53 completed tempering of the component 131 reaches the component 131 to complete this transfer process, ie at the time of filing the component 131 in the second system 120 , just the desired temperature there, ie during the transfer on the way between the first system 110 and the second system 120 on the component 131 acting thermal loads cancel with that for the purpose of compensation in the step S53 Temperierung just on each other.

While the invention has been described in terms of specific embodiments, numerous variations and alternative embodiments, e.g. by combination and / or exchange of features of individual embodiments. Accordingly, it will be understood by those skilled in the art that such variations and alternative embodiments are intended to be embraced by the present invention, and the scope of the invention is to be limited only in terms of the appended claims and their equivalents.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1531364 B1 [0008]

Claims (14)

A method of controlling a component, which component is convertible between a first system and a second system, the method comprising the steps of: a) determining a temperature drift of a temperature of the component (131) to be expected after transfer of the component (131) from the first system (110) to the second system (120); b) modifying a temperature present in the first system (110) and / or a temperature present in the second system (120) such that, after the component (131) has been transferred from the first system (110) to the second system ( 120) is actually reducing temperature drift compared to the determined in step a) expected temperature drift is reduced. Method according to Claim 1 characterized in that step a) comprises measuring a temperature currently present in the first system (110) and / or measuring a temperature currently present in the second system (120). Method according to Claim 1 or 2 characterized in that step a) comprises performing temperature measurements using a sensor attached to the component before and / or after transferring the component (131) from the first system (110) to the second system (120). Method according to one of Claims 1 to 3 characterized in that step a) comprises establishing a predictive model for predicting a temporal evolution of the temperature of the component (131) after transferring the component (131) from the first system (110) to the second system (120). Method according to one of the preceding claims, characterized in that the step b) comprises modifying the setpoint of a in the first system (110) and / or in the second system (120) existing temperature control. Method according to one of the preceding claims, characterized in that the step b) comprises modifying the operation of at least one component present in the first system (110) and / or in the second system (120). Method according to one of the preceding claims, characterized in that the method further comprises the steps of: - determining a change in the thermal state of the component (131) to be expected on the way from the first system (110) to the second system (120); and - tempering the component (131) prior to transferring it to the second system (120) such that this expected change is at least partially compensated. A method of controlling a component, which component is convertible between a first system and a second system, the method comprising the steps of: Determining a change in the thermal state of the component (131) to be expected on the way from the first system (110) to the second system (120); and • Tempering the component (131) prior to transfer to the second system (120) such that this expected change is at least partially compensated. Method according to Claim 7 or 8th , characterized in that the component (131) before the tempering in one of at least one further in the first system (110) located component (132, 133) separated area is transferred. Method according to one of Claims 7 to 9 characterized in that determining a change in the thermal state of the component (131) to be expected on the way from the first system (110) to the second system (120) is simulated and / or measured by the influence of thermal loads imposed on the component (131) is exposed on the way from the first system (110) to the second system (120). Method according to one of the preceding claims, characterized in that the component (131) is an optical component. Method according to one of the preceding claims, characterized in that the component (131) is adapted to a Prüflingsgeometrie optical alternating component, in particular a calibration with matched to the specimen geometry mirror curvature and / or adapted to the specimen geometry mirror diameter. Method according to Claim 12 , characterized in that the first system (110) is a magazine for supporting a plurality of alternating optical components. Method according to one of the preceding claims, characterized in that the second system (120) is a measuring arrangement for testing a mirror, in particular a mirror of a microlithographic projection exposure apparatus.

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