DE102006014298A1 - Integrated circuit`s structural component manufacturing method, involves performing thermal baking-out process in coating for diffusion of acids into polymer in lacquer such that acids are split up into process-soluble groups - Google Patents

Abstract

The method involves hardening a photosensitive lacquer for forming a lacquer coating on a substrate. The coating is exposed for forming acids based on a photolytic acidifier of the lacquer. A thermal baking-out process is performed in the coating for diffusion of the acids into a polymer in the lacquer such that the acids are split up into process-soluble groups. The coating is processed for forming structural components, where the process is performed with a pressure of less than 1 bar such that gaseous decomposition products are diffused out from the coating. An independent claim is also included for an arrangement for performing a thermal baking-out process, comprising a heating plate.

Description

The The invention relates to a process for the production of structural elements in a photosensitive resist on a substrate in which a high resolution in terms of structure sizes can be achieved can. The invention further relates to a thermal baking process (Post-Exposure-Bake), which immediately after an exposure of the varnish will, as well as the implementation this process on e.g. a hot plate.

The Manufacture of integrated circuits is subject to continuing Strive for ever smaller feature sizes in the circuits to create realized structural elements. This development process takes place simultaneously in different areas of semiconductor manufacturing takes place and in particular concerns the lithographic techniques. So be For example, the projection systems improved, increasingly smaller Exposure wavelengths selected, or sophisticated types of photomasks used. Also in the area the photosensitive resist used in the exposure There has been a significant development in recent years.

Technical Have improvements in one of the lithographic techniques mentioned the consequence that significant requirements also apply to each other Lithography techniques are provided. So have to be at the transition of exposure wavelengths in the DUV range (157 nm, 193 nm) up to the EUV range (10-15 nm) Structure widths of 20-50 nm with respect to the elements formed in the paint can only be realized in addition also developed improved resists and the associated resist processes become.

in the The field of coatings itself was achieved by the development of chemically reinforced coatings (chemical amplified resists, CAR) in the last decade Progress (see review article in Ito, H., "Deep UV resists: evolution and status ", in Solid State Technology, July 1996, pp. 164-170). These paints are based on the principle of acid catalyzed cleavage of protecting groups. This applies at least in the case of the frequently used positive resists, in which exposed areas in the paint due to a subsequent development step are removable.

To the Example is given by the exposure within the cured, solid lacquer layer deposited on a substrate, such as a wafer is a strong sulfonic acid educated. After exposure usually becomes a thermal Bake step, also called Post-Exposure-Bake (PEB), performed. This thermal annealing step serves the improved diffusion of the reactants in the photosensitive paint.

The Sulfonic acid formed in this example diffuses in the paint the usually polymer-bound reactants. It acts there as a catalyst for the protection group split. For example, the protecting groups may be to polymer bound carboxylic acid esters act. The acid catalyzed cleavage results in this case in a polymer-bound carboxylic acid or an alcohol, as well in another, often volatile, cleavage product, here is released.

at the cleavage product may be, for example, lower alcohols or alkenes act. An exemplary alkene is isobutene, resulting from the split a tert-butyl ester protecting group or a t-BOC protecting group results. It should be noted that these protection groups and cleavage products are just examples of which the invention do not restrict should.

A special requirement is the diffusion of acid catalytically fissuring acid, about the sulfonic acid, adjust so that an optimal contrast in the exposure of the paint is achieved. Is namely the diffusion of the acid in the otherwise solid paint too low, so can not be enough Protecting groups are split, so the paint is not the required Having photosensitivity.

is On the other hand, the diffusion too strong, so diffuse by exposure produced sulfonic acids too far into unexposed areas of the paint, so that the desired Blur contrasting structure edges. This effect will also called "image blur".

It Consequently, there is a need to diffusion of an acid catalytically fissuring acid to enable their range is limited, but the split sufficient allowed many protective groups, so that a sufficient photosensitivity of the paint is ensured. The impact of far more diffuse Particles with big ones Reach, on the other hand, is reduced or completely compensated so that no image blur effects arise.

• – Belacken des Substrats mit dem fotoempfindlichen Lack, welcher Basispolymere mit säurespaltbaren Gruppen und einen fotolytischen Säurebildner aufweist,
• – Aushärten des fotoempfindlichen Lacks zur Bildung einer festen Lackschicht auf dem Substrat;
• – Belichten der Lackschicht zur Bildung von Säuren anhand des fotolytischen Säurebildners in belichteten Abschnitten der Lackschicht;
• – Anwenden eines thermischen Heizprozesses auf die Lackschicht zur Diffusion der Säuren hin zu den Basispolymeren, sodass diese im Entwickler lösliche Gruppen aufgespaltet werden;
• – Entwickeln der Lackschicht zum Entfernen der aufgespalteten, Entwickler löslichen Gruppen und zur Bildung der Strukturelemente; wobei: der Heizprozess bei einem Druck von weniger als 1 bar durchgeführt wird, sodass bei Spaltprozessen entstandene gasförmige Spaltprodukte beschleunigt aus der Lackschicht ausdiffundieren.

Therefore, a method is proposed for producing structural elements in a photosensitive resist on a substrate, which comprises:

• Coating the substrate with the photosensitive resist comprising base polymers having acid-cleavable groups and a photolytic acid generator;
• - curing the photosensitive resist to form a solid resist layer on the substrate;
• - exposing the lacquer layer to form acids based on the photolytic acid generator in exposed portions of the lacquer layer;
• Applying a thermal heating process to the lacquer layer to diffuse the acids to the base polymers such that these developer-soluble groups are split;
• Developing the lacquer layer to remove the split, developer-soluble groups and to form the structural elements; wherein: the heating process is carried out at a pressure of less than 1 bar, so that gaseous fission products formed during fission processes accelerate out of the lacquer layer.

Around the pressure of less than 1 bar during the thermal heating process To realize, at least one share before this heating process evacuated an atmosphere surrounding the substrate with the paint layer become.

A special embodiment provides, for example, the thermal Heating process to perform on a hot plate, in an evacuated chamber is arranged. Evacuatable here means that the chamber devices by which the substrate surrounding the substrate in the chamber the atmosphere can be sucked off.

Further, exemplary embodiments provide, the evacuation so far perform, that pressures be achieved by less than 0.1 bar. The withdrawal of cleavage products from the solid lacquer layer is particularly efficient at these scales. Further improvements are achieved when the pressure is reduced to less can be lowered as 0.01 bar.

It It is proposed to carry out a post-exposure thermal Heating process, that is a post-exposure bake step (PEB), under reduced pressure or under quasi vacuum-like To perform conditions. By the thermal annealing step itself, the diffusion the acid catalytically splitting acids as well as the respective Reaction products increased.

By the pressure-reduced atmosphere gets over it also known as "thermodynamic Trap "to be designated Effect exploited. Namely, they will in particular the gaseous fission products formed during the catalytic cracking faster due to the reduced ambient pressure from the solid Paint layer drawn than that provided in the conventional case is. By the faster withdrawal of fission products away from the place the reaction that takes place in each case becomes the overall process of Cleavage reaction significantly accelerated.

by virtue of the accelerated cleavage reaction is therefore possible at the same efficiency of the catalyzed cleavage that for the thermal Raking step required time to shorten in particular.

Becomes but now the time for shortens the post-exposure bake step (this time is called the hold time), so can the acid catalytically-splitting acids at one of the bake temperature dependent Diffusion coefficients no longer reach as wide a range as it is conventionally the case. Consequently, the extent of diffusion due to the proposal according to the invention at the same efficiency in terms of the number of reactions significantly reduced. The image blur effect thereby takes a back seat.

The Method is applicable to any types of substrates, such as Semiconductor wafers, photomasks, or flat panel displays, etc. The method can be used with particular advantage where structural elements to be formed, which have widths of less than 60-70 nm, in particular Widths in the range of 20-50 nm.

When Structural elements in the paint become here after the development process resulting column in the resist (positive resist) or the between the columns stand for permanent webs (negative resist). Typically, once the structural elements formed in the paint following an etching process subjected to them in an underlying layer of the substrate or to transfer into its crystalline base material. Lackmasken but could for others Purposes, about for an implantation can be used. Subsequently, they will stand still Resist parts removed.

The Invention is also not on any particular type of lacquer or lacquer layer limited. It is crucial that the paint bound to base polymers, acid-cleavable Has groups that can be cleaved by liberated acids, which in turn through a photolytic acid generator to be generated. In terms of of the photolytic acid generator This can be applied to any wavelengths of incident light react, the term "light" in particular also Particle beams, such as electrons or ions, or other radiation includes. So there are no restrictions in the choice of the acidifier.

The The invention is not limited to any particular type of varnish. typically, a spin process can be used, but there are other possibilities as well to consider the application.

Further advantageous embodiments of the invention are the dependent claims to entneh men.

The Invention will now be described with reference to an embodiment with the aid of a Drawing closer explained become. Show:

1 in a flow chart, a sequence of steps according to an embodiment of the invention;

2 a schematic representation of a device with heating plates and evacuated chamber for performing a post-exposure bake step according to an embodiment of the invention;

3 and 4 Diagrams with traces for a PEB step where the layer thickness remaining after development is plotted against the applied radiation dose for different holding times and temperatures.

1 shows in a flow chart an exemplary sequence for the inventive method. Before the first step shown in the diagram 10 can in this embodiment, the coating of the 4-inch semiconductor wafer to be processed here as a substrate 116 with an adhesion promoter, such as a novolac layer. By spin coating at a speed of 5000 rpm (rounds per minute), a novolac solution (BLC 001 from Tokyo Ohka) is applied to the substrate surface for 20 s.

On a hot plate (hereinafter also referred to as hotplate) is the substrate for a period of 90 s at 110 ° C dried. Subsequently, will another annealing or annealing step on a hotplate for 90 seconds 235 ° C executed.

In the step 10 now becomes the substrate 116 by spin coating for 20 s at a speed of 2200 rpm with a chemically amplified and photosensitive lacquer 118 (a positive resist, also a Chemically Amplified Resist CAR). In this embodiment, it is the paint AR 1221 JSR.

In the step 20 becomes the paint 118 hardened. He is fed to a hotplate and dried for 90 s at 130 ° C. The lacquer now forms a solid lacquer layer of, for example, 190 nm film thickness (FT, film thickness).

In the following step 30 the substrate or the lacquer layer is exposed in an exposure apparatus with the pattern of a gray wedge mask. The exposure device is in this example a DUV Maskaligner type MJB 3 of Karl Suess GmbH. A 248 nm bandpass filter with polychromatic illumination of HgXe lamp is used. The gray wedge mask comes from the company Ditric Optics and has on transparent substrate (eg quartz) chromium fields of different transparency. It is a test mask demonstrating the effect of the present invention.

The exposure apparatus is, for example, set up so that the pattern on the gray wedge mask is irradiated by radiation from the illumination source and via projection optics onto the surface of the paint layer 118 on the substrate 116 is focused.

Due to the different transparency of the chrome fields areas of different dose in the paint layer 118 educated. The chromatic field transitions range from 0.18% (nearly complete light attenuation) to 100.00% (no attenuation) Alternatively, a sequence of exposures of many substrates, each with different exposure times, could be used to achieve different dose levels on the substrate In the present case, a dose of, for example, 0.5 mJ / cm ^{2 was used} at an exposure time of 10 s, whereby this should be multiplied by the respective transparency.

In a next step 40 The substrate with the exposed lacquer layer on a hotplate 110 provided. It is a thermal annealing step (post-exposure beacon) are performed, which is used to fix the latent image in the paint layer 118 serves.

The hotplate 110 is part of an arrangement 130 for carrying out the thermal heating step. An example of such an arrangement 130 is in schematic representation in 2 shown. The arrangement has a glass hood 120 (Exxikator-lid). The glass hood 120 forms with a pad 112 an evacuable chamber 122 in which the hotplate 110 is arranged. A vacuum pump 126 is with an inlet and outlet opening 124 in the glass hood 120 connected.

By means of the vacuum pump 126 will be in the chamber 122 contained, the substrate 116 with the paint layer 118 surrounding atmosphere through the inlet and outlet 124 and a connected hose 125 abgenoen. It will reach a pressure of less than 0.01 bar within 1 second. The glass hood 120 is due to the external pressure on the pad 112 fixed.

The hotplate 110 is caused by an energy or heat source 114 kept at a temperature of 130 ° C (step 70 ), which was set in advance. The amount of time between placing the substrate 116 on the hotplate 110 and sucking off the atmos Phäre from the meantime closed lid is kept as short as possible. It may be provided a substrate holder (schematically by reference numerals 132 indicated), which coordinates with the aspiration of the atmosphere by the vacuum pump 126 with the lid closed (glass hood 120 ) the substrate 116 on the hotplate 110 lowers, so that the heating process does not start before the generation of the vacuum.

In step 80 eg by removing the hose 125 a sudden ventilation of the chamber 122 performed, the glass hood 120 removed and the substrate 116 removed from the heating plate. The time from aspirating the atmosphere to venting the chamber 122 can according to step 60 be controlled by a control unit which controls a ventilation via, for example, a valve. It is 90 s in the first embodiment.

Next is the substrate 116 exposed for 60 seconds to an aqueous alkaline developer, eg TMA 238 WA from JSR. The chemically converted lacquer areas are thereby removed, so that the desired structural elements arise. Subsequently, the substrate is rinsed with water for 30 seconds, blown dry with compressed air and dried again dried at 90 ° C for 60 s.

In the case of a production mask with structures which are part of a pattern of an integrated circuit to be produced in the substrate instead of a gray wedge mask, the structural elements formed in the lacquer layer can now be further processed, for example by an etching or implantation process, etc. (step 100 ).

The effect of the invention demonstrated on the basis of the gray wedge mask will now be described with reference to FIG 3 be explained. In the diagram is that after the development (step 90 ) remaining layer thickness FT plotted against the irradiated in the paint layer dose applied for differently performed annealing steps or PEB processes. The curve labeled "vacuum 90 s" (left) shows results of a corresponding layer thickness measurement for the above embodiment (temperature 130 ° C. and vacuum for 90 s.) Each of the gray wedge or chrome fields on the mask leads to a measurement point on the x Axis in the diagram because it represents a certain dose according to its transparency.

It is clear from the curve "Vacuum 90 s" in 3 to recognize that freed of paint residues structural elements are obtained from a dose of about 0.130 mJ / cm ² .

There are two further embodiments of the invention performed in 3 shown. In contrast to the first example, the holding time for the PEB step was shortened at the same temperature (130 ° C) and the same mask structure (gray scale), exposure setting and same coating (AR1221): "Vacuum 30 s" or "Vacuum 15 s" , It is expected that the holding time for the PEB step will be shortened 70 a higher dose (about 0.150 or 0.190 mJ / cm ² ) necessary to complete development of the structural element down to the bottom of the lacquer layer 118 to get.

A comparison with the conventional case shows the curve "conventional 90 s" on the right side of the diagram 50 and 80 according to 1 omitted, ie the heating step 70 (PEB) was carried out under normal pressure (1013 mbar) for 90 s. It turns out that an even higher dose (0.210 mJ / cm ² ) is required for the exposure than in the case of just 15 seconds of PEB 70 when applying a vacuum (the term "vacuum" here includes pressures below 0.1 bar).

Around therefore one for a fixed radiation dose thermal annealing step (PEB) can be realized in the case of applying a vacuum according to the invention a considerably shorter one Holding time are set as in the conventional case without vacuum, nevertheless satisfactory results regarding the remaining lacquer layer thickness to obtain.

4 shows further analogous embodiments, wherein a temperature of 125 ° C instead of 130 ° C for the PEB process (step 70 ) has been set. The same resist AR1221 was used. The measured curves for a vacuum PEB process with a holding time of 15 s and for a conventional PEB process without a vacuum at 90 s holding time virtually coincide (the curve designations are analogous to) 3 ).

In the 5 - 7 For example, exemplary modifications of the inventive arrangement for performing a PEB process under reduced pressure or vacuum-like conditions are shown. 5 shows an arrangement 130 in which the cover 120 (here and in other examples not necessary glass) by a second heat source 140 is heated. As a result, the substrate can additionally be heat-irradiated homogeneously from above, and it is further prevented that the cleavage products of the chemical reactions are deposited on the hood and later fall through it by spalling onto a subsequent substrate contaminating it.

The careful removal of the cleavage products is also ensured by a cold trap 150 in the area of the exhaust air line 125 (eg Hose) of the vacuum pump. Gaseous cleavage products then strike the cool walls of the cold trap 150 by sublimation down. The cold trap can be cooled separately by a cooling device or simply cooled by the already cool outdoor air. Such a cold trap is in another context but with similar mode of action in the document DE 10 2004 021 392 A1 described.

Similar to the one in the cover 120 integrated heating mechanism, which provides additional heat radiation 142 generated ( 5 ), the cover also transparent to heat radiation through a further radiation source 160 be irradiated. The generated radiation 162 may include UV optical and / or infrared light and the surface of the substrate 116 or the lacquer layer 118 to irradiate homogeneously, as in 6 is shown.

7 shows a further embodiment of the arrangement according to the invention 130 , For cleaning the chamber 122 of reaction products, a plasma source is integrated into the chamber. A high frequency generator 170 generated by an AC voltage an alternating field with high field strengths, so that in the from a source 174 inflowing oxygen or argon gas a plasma is generated. The fission products deposited on the walls of the chamber are removed either physically or chemically reactive. The removal of the reaction products from the chamber can also be effected again by the vacuum pump.

In the case of in 7 The integrated hot plasma can act as a counter electrode. A substrate should not be placed when cleaning with the help of the plasma source.

Nevertheless, it is also provided according to the invention to excite the reactive gas externally and only then into the chamber 122 initiate.

Returning the mode of action of the pressure reduction applied to the post-exposure beacon can be determined the following effects: at the elevated temperatures during the Post-exposure Bakes can the volatile Fission products evaporate quickly from the paint and are therefore also quickly from their original one Protective group or by the delocalized protecting group acid complex as a transition state removed the acid-catalyzed cleavage reaction. This process is necessary to complete the cleavage reaction of the protecting groups to accelerate.

As far as the photosensitive lacquer 118 is present during the post-exposure bake process as a solid, but the outdiffusion of the cleavage products is difficult. Generally used paints are considered to be diffusion-inhibiting due to this solid character.

The elevated temperature during the post-exposure bake process is thus a prerequisite for the outdiffusion of the cleavage products. Further acceleration is now achieved by additionally creating a relative pressure reduction in the environment of the paint 118 possible. In addition to the purely thermal stimulation of the evaporation from the paint, the cleavage products are thereby literally sucked out of the paint.

A preferred diffusion direction is therefore given in the z direction. If the cleavage products are pulled vertically out of the paint, shows the reaction front also preferred in this direction. Consequently, will the lateral diffusion (image blur) is restricted by the pressure reduction.

Another effect is that of the chamber 122 a heat conductor (eg air) above the substrate 116 or the paint 118 is withdrawn. The heat insulation is thereby improved and the heat distribution is improved, in particular at the edges of the substrate. In addition, the substrate on the hot plate heats up faster, making the process easier to control.

As well as in the 5 - 7 In addition, harmful outgassing products may be present on surfaces of the hotplate 110 can be deposited and thus lead to defects on the substrate surface, be discharged in post-exposure bake process by the vacuum pump.

10-100

process steps

110

heating plate, hotplate

112

underground

114

heating source

116

substratum

118

paint

120

cover, glass dome

122

chamber

124

One- and outlet opening

125

Exhaust duct tube

126

Vakuupumpe

128

Atmosphere, air, evacuated

130

arrangement

132

Substrate holder, Wafer handler

140

heating source

142

thermal radiation

150

cold trap

160

radiation source

162

Thermal radiation, UV, IR

170

RF generator

172

cathode

174

gas source for reactive Gas, Ar, O

Claims (28)

Process for the preparation of structural elements in a photosensitive resist on a substrate, comprising: - coating the substrate ( 116 ) with the photosensitive resist comprising base polymers having acid-cleavable groups and a photolytic acid generator, - curing the photosensitive varnish to form a solid varnish layer ( 118 ) on the substrate ( 116 ); - exposure of the lacquer layer ( 118 ) to form acids from the photolytic acid generator in exposed portions of the lacquer layer; Applying a thermal heating process to the lacquer layer to diffuse the acids to the base polymers such that they are broken down into developer-soluble groups; - developing the paint layer ( 118 ) for removing the split, developer-soluble groups and for forming the structural elements; wherein: the heating process is carried out at a pressure of less than 1 bar, so that in the case of chemical splitting processes gaseous fission products accelerated out of the paint layer ( 118 ) diffuse out. Method according to claim 1, wherein prior to applying a thermal heating process to the lacquer layer ( 118 ) at least a portion of the substrate ( 116 ) with the paint layer ( 118 ) is evacuated to bring about the reduced relative to the normal ambient pressure pressure of less than 1 bar. Method according to claim 2, wherein the evacuation the atmosphere is carried out to a pressure of less than 0.1 bar. Method according to claim 2, wherein the evacuation the atmosphere is carried out to a pressure of less than 0.01 bar. Method according to one of the preceding claims, in the applied heating process is carried out with a holding time, which is more than 1 s and less than 300 s. Method according to claim 5, wherein the holding time more than 10 s and less than 90 s. Method according to one of the preceding claims, in which the exposure of the lacquer layer ( 118 ) is performed with visible optical, ultraviolet, extreme ultraviolet or electrically charged particles. Method according to one of the preceding claims, in which the substrate ( 116 ) is a semiconductor wafer or a photolithographic mask. Method according to one of the preceding claims, in which the heating process is carried out on a hotplate ( 110 ) carried out in an evacuable chamber ( 122 ) is arranged. Method according to claim 8, in which the evacuable chamber ( 122 ) before depositing the substrate ( 116 ) on the heating plate ( 110 ) and carrying out the thermal heating process with chemically inert gas is rinsed to separated fission products of a similar pre-process of the hot plate ( 110 ) to remove. Method according to claim 9 or 10, in which the evacuable chamber has a cover ( 120 ), which is thermally heated to irradiate the substrate with heat. The method of claim 11, wherein the cover ( 120 ) the chamber ( 122 ) is heated to the same temperature as the heating plate during the application of the heating process. Method according to one of claims 9 to 12, wherein the atmosphere from the chamber ( 122 ) via an exhaust duct ( 125 ) is evacuated, in which a cold trap ( 150 ), in which sublimatable particles can precipitate out of the diffused gaseous fission products. Method according to claim 9 or 10, wherein the evacuable chamber ( 122 ) a cover ( 120 ), which is used to irradiate the substrate ( 116 ) is transparent to ultraviolet, optical or infrared light emitted by a radiation source ( 160 ) outside the cover ( 120 ) on the substrate ( 116 ) with the paint layer ( 118 ) is irradiated. Method according to claim 11 or 14, wherein during the heating process heating of the substrate by the heating plate ( 118 ) is omitted, so that the heating process exclusively by the heat radiation by means of the heated cover ( 120 ) or by the irradiation by means of the radiation source ( 160 ) from outside the cover ( 120 ) is applied. Method according to one of claims 9 to 15, wherein in the evacuable chamber ( 122 ) in front Depositing the substrate ( 118 ) on the heating plate ( 110 ) and application of the heating process to the lacquer layer ( 118 ) and / or after applying the heating process and removing the substrate ( 116 ) using a plasma source ( 170 . 172 ) a plasma is ignited to the chamber ( 122 ) to clean. A method according to claim 16, wherein oxygen or argon is injected into the chamber to produce the plasma ( 122 ) is initiated. Method according to one of the preceding claims, in the heating step at a temperature of more than 100 ° C and less is performed as 180 ° C. The method of claim 18, wherein the heating step at a temperature of more than 120 ° C and less than 140 ° C is performed. The method of claim 1, wherein before the coating a bonding agent is applied. The method of claim 1, which prior to curing the Application of a further heating step includes. Arrangement ( 130 ) for carrying out a thermal heating process after performing an exposure of a substrate ( 116 ) coated with a photosensitive layer ( 118 ), comprising: - a heating plate ( 110 ) for receiving the substrate ( 116 ), - a cover ( 120 ), with a background 112 an airtight chamber 122 forms, in which the heating plate is arranged, - a vacuum pump ( 126 ) with an inlet and outlet opening ( 124 ) with the chamber ( 122 ) to evacuate an atmosphere contained therein, so that the pressure in the chamber ( 122 ) relative to the ambient pressure of the arrangement ( 130 ) can be lowered. Arrangement ( 130 ) according to claim 22, wherein the cover ( 120 ) for generating a thermal radiation directed onto the substrate ( 142 ) is heated. Arrangement ( 130 ) according to claim 22 or 23, wherein the heating plate ( 110 ) for transferring heat to an applied substrate ( 116 ) is heated. Arrangement ( 130 ) according to any one of claims 22-23, wherein outside the cover ( 120 ) and the chamber ( 122 ) a radiation source ( 160 ) for generating a heat radiation ( 162 ), wherein the cover ( 120 ) at least in a region between the radiation source ( 160 ) and the heating plate ( 110 ) transparent to the heat radiation ( 142 ). Arrangement ( 130 ) according to any of claims 22-25, wherein the vacuum pump ( 126 ) with an exhaust duct ( 125 ) with the chamber ( 122 ) and in the area of the exhaust air duct ( 125 ) a cold trap ( 150 ) for the sublimation of when performing the thermal heating process from the paint ( 118 ) outgassing fission products is established. Arrangement ( 130 ) according to one of the preceding claims, in which in the chamber ( 122 ) a plasma source ( 170 . 172 ) for carrying out a cleaning of the chamber ( 122 ) is provided. Arrangement according to Claim 27, in which the chamber ( 122 ) a gas source ( 174 ) for supplying a reactive gas, argon or oxygen is connected.